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Sample records for venus express mission

  1. The Venus Express mission

    NASA Astrophysics Data System (ADS)

    McCoy, Donald; Siwitza, Thorsten; Gouka, Roy

    2005-11-01

    Venus evokes the ever-attractive image of a goddess from antiquity, and yet our sister planet, although attractive, is far from hospitable. The reasons for such a great difference between Earth and Venus have still to be understood and so, considering that they are very close in terms of astronomical distances, a mystery is invoked. Whether Earth is a unique planet, for which life was destined, or whether both planets were created under similar circumstances and subsequently evolved in different manners, is fundamental to the understanding of our place in the Solar System and, indeed, perhaps the Universe.

  2. VIRTIS for the ESA Venus Express Mission

    NASA Astrophysics Data System (ADS)

    Piccioni, G.; Drossart, P.; Coradini, A.; Arnold, G.

    The VIRTIS experiment for the ESA Rosetta mission was considered perfectly suitable, after some minor modifications, to be one of the instrument core payload for an ESA mission called Venus Express. At the time when this abstract is written, the mission will undergo the final step for possible official approval. VIRTIS consists of two channels: VIRTIS-M, a mapping spectrometer with moderate spectral resolution and VIRTIS-H, an high spectral resolution spectrometer having its field of view within thefield of view of UM. The spectral range of VIRTIS-M is between 0.25um and 5um in two channels with a boundary at 1um and a resolution of 3nm and 30 nm respectively. The spectral range of VIRTIS-H is from 2 to 5um with a resolution of about 3nm. The main scientific objectives of VIRTIS for Venus are: study of the lower atmosphere composition below the clouds and its variations (CO, OCS, SO2, H2O); study of the cloud structure, composition, and scattering properties; cloud tracking in the UV (~70 km, day side) and IR (~50 km, night side); measurements of the temperature field with subsequent determination of the zonal wind in the altitude range 60-100km (night side); lightning search (night side); mesospheric sounding; search for variations related to surface/atmosphere interaction, dynamics, meteorology, and volcanism; temperature mapping of the surface, search for hot spots related to volcanic activity; search for seismic waves from propagation of acoustic waves amplified in the mesosphere. This mission would give us a great opportunity for an extensive observation of Venus after the first attempts of imaging spectrometry performed by NIMS/Galileo and VIMS/Cassini whose flybys gave us the idea of the powerful of this type of investigation.

  3. The legacy of Venus Express: highlights from the first European planetary mission to Venus

    NASA Astrophysics Data System (ADS)

    Drossart, Pierre; Montmessin, Franck

    2015-11-01

    The ESA/Venus Express mission spent more than 8 years in orbit around Venus to extensively study its atmosphere, ionosphere and plasma environment and unveil new aspects of its surface. Extensive reviews of the work of Venus Express are underway, to cover in-depth studies of the new face of Venus revealed by Venus Express and ground-based concurrent observations. This paper intends to give a summarized and wide overview of some of the outstanding results in all the science areas studied by the mission. This paper will first review the main aspects of the mission and its instrumental payload. Then, a selection of results will be reviewed from the outermost layers interacting with the Solar wind, down to the surface of Venus. As Venus Express is already considered by space agencies as a pathfinder for the future of Venus exploration, perspectives for future missions will be given, which will have to study Venus not only from orbital view, but also down to the surface to solve the many remaining mysteries of the sister planet of the Earth.

  4. A compilation of all CO observations performed by SOIR during the Venus Express mission

    NASA Astrophysics Data System (ADS)

    Vandaele, A. C.; Mahieux, A.; Chamberlain, S.; Ristic, B.; Robert, S.; Thomas, I. R.; Trompet, L.; Wilquet, V.; Bertaux, J.-L.

    2015-10-01

    The SOIR instrument on board the ESA Venus Express spacecraft has been operational during the complete duration of the mission, from April 2006 up to November 2014. Spectra are recorded in the IR spectral region (2.2 -4.3 ?m) using the solar occultation geometry and give access to a vast number of ro-vibrational lines and bands of several key species of the atmosphere of Venus. Here we present the complete set of vertical profiles of carbon monoxide (CO) densities and volume mixing ratios (vmr) obtained during the mission. These profiles are spanning the 65-150 km altitude range. We discuss the variability which is observed on short term, but also the long term trend as well as variation of CO with solar local time (LST) and latitude.

  5. Venus Aerobot Multisonde Mission

    NASA Technical Reports Server (NTRS)

    Cutts, James A.; Kerzhanovich, Viktor; Balaram, J. Bob; Campbell, Bruce; Gershaman, Robert; Greeley, Ronald; Hall, Jeffery L.; Cameron, Jonathan; Klaasen, Kenneth; Hansen, David M.

    1999-01-01

    Robotic exploration of Venus presents many challenges because of the thick atmosphere and the high surface temperatures. The Venus Aerobot Multisonde mission concept addresses these challenges by using a robotic balloon or aerobot to deploy a number of short lifetime probes or sondes to acquire images of the surface. A Venus aerobot is not only a good platform for precision deployment of sondes but is very effective at recovering high rate data. This paper describes the Venus Aerobot Multisonde concept and discusses a proposal to NASA's Discovery program using the concept for a Venus Exploration of Volcanoes and Atmosphere (VEVA). The status of the balloon deployment and inflation, balloon envelope, communications, thermal control and sonde deployment technologies are also reviewed.

  6. The Pioneer Venus Missions.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Mountain View, CA. Ames Research Center.

    This document provides detailed information on the atmosphere and weather of Venus. This pamphlet describes the technological hardware including the probes that enter the Venusian atmosphere, the orbiter and the launch vehicle. Information is provided in lay terms on the mission profile, including details of events from launch to mission end. The…

  7. The Challenges and Opportunities for International Cooperative Radio Science; Experience with Mars Express and Venus Express Missions

    NASA Technical Reports Server (NTRS)

    Holmes, Dwight P.; Thompson, Tommy; Simpson, Richard; Tyler, G. Leonard; Dehant, Veronique; Rosenblatt, Pascal; Hausler, Bernd; Patzold, Martin; Goltz, Gene; Kahan, Daniel; Valencia, Jose

    2008-01-01

    Radio Science is an opportunistic discipline in the sense that the communication link between a spacecraft and its supporting ground station can be used to probe the intervening media remotely. Radio science has recently expanded to greater, cooperative use of international assets. Mars Express and Venus Express are two such cooperative missions managed by the European Space Agency with broad international science participation supported by NASA's Deep Space Network (DSN) and ESA's tracking network for deep space missions (ESTRAK). This paper provides an overview of the constraints, opportunities, and lessons learned from international cross support of radio science, and it explores techniques for potentially optimizing the resultant data sets.

  8. The Pioneer Venus Missions

    NASA Technical Reports Server (NTRS)

    Hall, C. F.

    1979-01-01

    Two spacecraft with scientific instruments, a Multiprobe and an Orbiter, were sent to Venus by the USA in 1978 and successfully performed a series of measurements of the Venusian environment, in situ from the probes and remotely from the Orbiter. The paper discusses the scientific objectives of the missions, describes the spacecraft and trajectories, presents the performance of the spacecraft and instruments, and summarizes the scientific findings. The results indicate an excess of primordial argon at Venus; four distinct cloud layers were observed; four widely separated sites in both daylight and night time show almost no differences in atmospheric temperature and pressure below about 50 km altitude; winds up to 200 m/sec were observed at high altitudes; large plateaus were identified on the surface.

  9. Venus Express ready for lift-off

    NASA Astrophysics Data System (ADS)

    2005-10-01

    Venus Express is Europe’s first mission to Venus, a place of many mysteries that scientists are still eager to solve. Principal among those mysteries is why a planet so similar to the Earth in size, mass, and composition has evolved so differently over the course of the last 4.6 billion years. ESA’s ESOC establishment, the Space Operations Centre in Darmstadt, Germany will control the mission and organise a launch event from 06:00 to 12:00. A live televised transmission of the launch will bring images from Baikonur to broadcasters and the general public. ESA senior management and specialists will be on hand at ESOC and at other ESA establishments for explanations and interviews. All live transmissions are carried free-to-air. For broadcasters, complete details of the various satellite feeds (on Eutelsat W2) are listed at http://television.esa.int. For the general public, a launch transmission via Astra 1G has again been organised, with all schedule and transmission details online at http://television.esa.int/photos/Astra.pdf On the occasion of the launch of Venus Express, the Planetary Society has teamed up with ESA to invite youths and adults worldwide to enter a Venus Express Art Contest. The theme of the contest is "Postcards from Venus". Entrants are invited to imagine the surface of Venus from an above-ground perspective. The winner will be invited to follow the Venus Orbit Insertion event at ESA's control centre in Darmstadt, Germany, on 6 April 2006. More on the constest at http://planetary.org/postcards_from_venus/ Media representatives wishing to follow the event at ESA/ESOC, or the retransmission at other ESA establishments, are requested to fill in the attached registration form and fax it back to the place of their choice.

  10. A Venus Flagship Mission: Exploring a World of Contrasts

    NASA Astrophysics Data System (ADS)

    Senske, D.; Bullock, M.; Balint, T.; Benz, A.; Campbell, B.; Chassefiere, E.; Colaprete, A.; Cutts, J.; Glaze, L.; Gorevan, S.; Grinspoon, D.; Hall, J.; Hasimoto, G.; Head, J.; Hunter, G.; Johnson, N.; Kiefer, W.; Kolawa, E.; Kremic, T.; Kwok, J.; Limaye, S.; Mackwell, S.; Marov, M.; Peterson, C.; Schubert, G.; Spilker, T.; Stofan, E.; Svedhem, H.; Titov, D.; Treiman, A.

    2008-12-01

    Results from past missions and the current Venus Express Mission show that Venus is a world of contrasts, providing clear science drivers for renewed exploration of this planet. In early 2008, NASA's Science Mission Directorate formed a Science and Technology Definition Team (STDT) to formulate science goals and objectives, mission architecture and a technology roadmap for a flagship class mission to Venus. This 3- to 4 billon mission, to launch in the post 2020 timeframe, should revolutionize our understanding of how climate works on terrestrial planets, including the close relationship between volcanism, tectonism, the interior, and the atmosphere. It would also more clearly elucidate the geologic history of Venus, including the existence and persistence of an ancient ocean. Achieving these objectives will provide a basis to understand the habitability of extra solar terrestrial planets. To address a broad range of science questions this mission will be composed of flight elements that include an orbiter that is highlighted by an interferometric SAR to provide surface topographic and image information at scales one to two orders of magnitude greater than that achieved by any previous spacecraft to Venus. Two balloons with a projected lifetime of weeks will probe the structure and dynamics of the atmosphere at an altitude of 50 to 70-km. In addition, two descent probes will collect data synergistic to that from the balloon and analyze the geochemistry of surface rocks over a period of hours. The technology road map focuses on key areas of science instruments and enabling engineering to provide greater in situ longevity in the hostile Venus environment.

  11. Mission concepts for Venus surface investigation

    NASA Astrophysics Data System (ADS)

    Hoffman, S. J.; Feingold, H.; Friedlander, A.

    1981-08-01

    Mission concepts for the in situ investigation of the Venus atmosphere and surface in the period following the VOIR mission are discussed. The science issues in Venus exploration and possible means of meeting the scientific objectives are considered, including global mapping, surface composition determination, atmospheric composition determination and surface-atmosphere interactions. Particular attention is then given to the feasibility of buoyant stations for atmospheric observation, balloon-tether combinations for surface observations, and the active thermal control by a reversed Brayton cycle or a vapor compression cycle of a long-lived Venus lander. Of the concepts examined, it is found that only the balloon-tether system would be impractical for the mission outlined for it, while the other two concepts appear feasible.

  12. The clouds of Venus - an overview of Venus Express results

    NASA Astrophysics Data System (ADS)

    Wilson, C. F.; Marcq, E.; Markiewicz, W. J.; Montmessin, F.; Fedorova, A.; Wilquet, V.; Petrova, E. V.; Ignatiev, N. I.; Shalygina, O. S.; Maattanen, A. E.; McGouldrick, K. M.; Hashimoto, G. L.; Imamura, T.; Rossi, L.; Luginin, M.; Oschlisniok, J.; Haus, R.; Parkinson, C. D.; Titov, D. V.; Zasova, L. V.; Limaye, S. S.

    2015-10-01

    Venus is completely enveloped by clouds. The main cloud layers stretch from altitudes of 48 -75 km, with additional tenuous hazes found at altitudes 30 -100 km. Clouds play a crucial role in governing atmospheric circulation, chemistry and climate on all planets, but particularly so on Venus due to the optical thickness of the atmosphere. The European Space Agency's Venus Express (VEx) satellite has carried out a wealth of observations of Venus clouds since its arrival at Venus in April 2006. Many VEx observations are relevant to cloud science -from imagers and spectrometers to solar, stellar and radio occultation -each covering different altitude ranges, spectral ranges and atmospheric constituents

  13. Magnetic observations of Venus ionosphere during Venus Express aerobraking campaign

    NASA Astrophysics Data System (ADS)

    Zhang, Tielong; Baumjohann, Wolfgang; Russell, Christopher; Luhmann, Janet

    2015-04-01

    During the late days of the Venus Express mission, an aerobraking campaign was performed in May - July 2014. The altering of the spacecraft orbit allows the pericenter went to as low as 129.7 km in altitude, which is well below the main peak ionosphere altitude of ~140 km. Magnetic observations during aerobraking campaign shows that the Venus ionosphere exhibits the same magnetic properties as observed by Pioneer Venus Orbiter (PVO) during solar maximum for altitude above 150 km which was the lowest altitude reached by PVO: magnetized ionosphere with large-scale horizontal magnetic field; or unmagnetized ionosphere with numerous small-scale thin structures, so-called flux ropes. However, around or below main peak ionosphere altitude, we find only very low background magnetic field of several nanotesla, without any large magnetic belt or larger spikes of fields, the so-called flux ropes. Apparently the magnetization of the ionosphere or the penetration of the magnetic ropes stops at main peak ionosphere altitude.

  14. Geochemistry of Venus: Progress, Prospects and New Missions

    NASA Astrophysics Data System (ADS)

    Treiman, A. H.

    2009-04-01

    Available geochemical data on Venus' surface materials are limited and of poor precision. Those data were obtained by the Venera and VEGA lander missions, which were engineering and scientific triumphs of their days. However, their chemical analyses of the Venus surface do not permit detailed geochemical interpretations, such as are routine for terrestrial analyses and MER APXS rover analyses from Mars. In particular, the Venera and VEGA analyses of major elements (by XRF) did not return abundances of Na, and their data on Mg and Al are little more than detections at the 2s level. Their analyses for K, U, and Th (by gamma rays) are imprecise, except for one (Venera 8) with extremely high K contents (~4% K2O) and one (Venera 9) with a non-chondritic U/Th abundance ratio. In addition, the Venera and VEGA landers sampled only materials from the Venus lowlands - they did not target sites in any of the highland areas: shield volcanoes, tesserae, nor the unique plateau construct of Ishtar Terra. The Virtis imaging spectrometer on Venus Express has provided new global data of likely geochemical importance - maps of surface emittance at near 1.2 µm - but it remains unclear just what causes its observed variations in emittance. The limitations of the available data on Venus' surface rock compositions and mineralogy highlight the huge opportunities in additional chemical and mineralogical analyses of Venus' surface. In geochemistry, currently available instruments could provide much more precise analyses for major and minor elements, even within the engineering constraints of the Venera / VEGA lander systems. Such precise analyses would be welcome for basalts of Venus' lowland plains, but would be especially desirable for the highland tesserae and for Ishtar Terra. The tesserae may well represent ancient crust that predates the most recent volcanic resurfacing event and so provide a geochemical look into Venus' distant past. Ishtar Terra may be composed (at least in part) of granitic rocks like Earth's continental crust, which required abundant water to form. So, Ishtar Terra could possibly yield evidence on whether Venus once had an ocean, and thus the possibility of life. The mineralogy of Venus' surface materials will reflect not only its rocks, but also their chemical weathering in the hot, dense, corrosive Venus atmosphere. Mineralogical instruments at the Venus surface (like XRD or Raman) could test various theories of surface atmosphere interactions, like carbonate buffering of atmospheric CO2, sulfide/sulfate buffering of SO2, and origin of Venus' low emissivity highlands as iron sulfide or as metallic tellurium frost. The geochemistry of Venus' surface would be learned best in lander missions, which are under consideration from several agencies. Current mission concepts are severely limited durations at Venus' surface before they succumb to its high temperature. However, high-temperature electronics and power systems are under development. Surface-atmosphere interactions, and hence surface mineralogy, can be constrained indirectly by probes of Venus' lower atmosphere (with or without soft landing). And improved radar imagery and altimetry can provide crucial indirect constraints on surface mineralogy and geology via emissivity and geophysical constraints (e.g., whether Ishtar Terra could be a granitic continent).

  15. Venera-D -the future Russian mission to Venus

    NASA Astrophysics Data System (ADS)

    Zasova, Ludmila; Zelenyi, Lev; Korablev, Oleg; Sanko, N. F.; Khartov, Victor V.; Vorontsov, Victor A.; Basilevsky, A. T.; Pichkhadze, Konstantin M.; Elkin, Konstantin S.; Voron, Victor V.

    Venus was actively studied by Soviet and US mission in 60-80-th years of the last century. The investigations carried out both from the orbit and in situ were highly successful. After a 15-years break in space research of Venus, the ESA Venus Express mission, launched in 2005, successfully continues its work on orbit around Venus. In 2010 the launch of the Japanese Climate Orbiter (Planeta-C) mission is planned. However, many questions concerning the structure, and evolu-tions of planet Venus, which are the key questions of comparative planetology, very essential for understanding the evolution of the terrestrial climate, cannot be solved by observations from an orbit. Now in Russia the new investigation phase of Venus begins: the mission Venera-D is included in the Russian Federal Space Program to be launched in 2016. This mission includes the lander, balloons, and the orbiter. The long living balloons are planned to be deployed at different heights, in the clouds and under the clouds. Scientific goals of the mission include: -investigation of structure, chemical composition of the atmosphere, including noble gases abundance and isotopic ratio, structure and chemistry of the clouds; -study of dynamics of the atmosphere, nature of the superrotation, radiative balance, nature of an enormous greenhouse effect; -study of structure, mineralogy and geochemistry of the surface, search for seismic and volcanic activity, the lightening, interaction of the atmosphere and the surface; -investigation of the upper atmosphere, ionosphere, magnetosphere, and the escape rate; -study of the evolution of the atmosphere and the surface of Venus. The complex of experiments on the orbiter includes, among the others, several spectrometers in the spectral range from UV to MW, the mapping spectrometers and the plasma package. On the lander there are instruments to work during the descent, and on the surface: gas-chromatograph, PTW (meteo), nephelometer and the particle sizes spectrometer, optical package, active gamma-spectrometer, TV-complex, which includes panoramic, high resolution and descending cameras.. On the balloon which has to work near the lower boundary of clouds, the devices will be installed to study the lower atmosphere and to get the surface images with high resolution at 1 mkm. Successful realization of the project Venera-D will allow to solve the important scientific problems of comparative planetology. In particular it will help to understand why do Venus and the Earth (sister-planets), similar in many aspects, being formed at similar conditions in the protoplanet nebula, evolve by such a different way.

  16. The final year of Venus Express

    NASA Astrophysics Data System (ADS)

    Svedhem, Håkan

    2015-04-01

    The Venus Express mission ended in December 2014 after having run out of fuel after 8.5 years of continuous operation in orbit around our sister planet. The last year in operation was characterised by a number of dedicated science campaigns and the aerobraking in June-July, and the subsequent special operations in the new 22.5 hour orbit post aerobraking. This talk will summarise the activities and the main results of the last year in operation, including the aerobraking, and discuss the events leading up to the declaration of end of mission following the end of fuel condition.

  17. Systems Analysis for a Venus Aerocapture Mission

    NASA Technical Reports Server (NTRS)

    Lockwood, Mary Kae; Starr, Brett R.; Paulson, John W., Jr.; Kontinos, Dean A.; Chen, Y. K.; Laub, Bernard; Olejniczak, Joseph; Wright, Michael J.; Takashima, Naruhisa; Justus, Carl G.

    2006-01-01

    Previous high level analysis has indicated that significant mass savings may be possible for planetary science missions if aerocapture is employed to place a spacecraft in orbit. In 2001 the In-Space Propulsion program identified aerocapture as one of the top three propulsion technologies for planetary exploration but that higher fidelity analysis was required to verify the favorable results and to determine if any supporting technology gaps exist that would enable or enhance aerocapture missions. A series of three studies has been conducted to assess, from an overall system point of view, the merit of using aerocapture at Titan, Neptune and Venus. These were chosen as representative of a moon with an atmosphere, an outer giant gas planet and an inner planet. The Venus mission, based on desirable science from plans for Solar System Exploration and Principal Investigator proposals, to place a spacecraft in a 300km polar orbit was examined and the details of the study are presented in this paper.

  18. Densities and temperatures in the Venus mesosphere and lower thermosphere retrieved from SOIR on board Venus Express: Carbon dioxide measurements at the Venus terminator

    NASA Astrophysics Data System (ADS)

    Mahieux, A.; Vandaele, A. C.; Robert, S.; Wilquet, V.; Drummond, R.; Montmessin, F.; Bertaux, J. L.

    2012-07-01

    SOIR is a high-resolution spectrometer flying on board the ESA Venus Express mission. It performs solar occultations of the Venus high atmosphere, and so defines unique vertical profiles of many of the Venus key species. In this paper, we focus on the Venus main constituent, carbon dioxide. We explain how the temperature, the total density, and the total pressure are derived from the observed CO2 density vertical profiles. A striking permanent temperature minimum at 125 km is observed. The data set is processed in order to obtain a Venus Atmosphere from SOIR measurements at the Terminator (VAST) compilation for different latitude regions and extending from 70 up to 170 km in altitude. The results are compared to many literature results obtained from ground-based observations, previous missions, and the Venus Express mission. The homopause altitude is also determined.

  19. Venus Monitoring Camera Observations and Results from Venus Express

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay; Krauss, R. J.; Markiewicz, W. J.; Titov, D. V.; Khatuntsev, I.; Patsaeva, M.

    2010-10-01

    The Venus Monitoring Camera (VMC) on ESA's Venus Express mission has been systematically imaging the planet in four filters since June 2006. These images from the 24-hour eccentric, polar orbit show the dynamic behavior of the Venus cloud cover with rapid changes in relative brightness on global, regional and small scales and presence of planetary scale and small scale gravity waves (high Northern latitudes). They have enabled estimates of the large scale circulation of the cloud level flow from multiple, independent efforts for the southern hemisphere which is imaged routinely. The results are generally consistent and appear to show presence of planetary waves and solar thermal tides. The precise vertical level of the measured cloud motions is not known but has been estimated to be between 70 km at low latitudes and 65 km in polar regions with a rise near the mid-latitudes to about 73 km. Temporal or local solar time changes in the cloud top level appear possible but have not been investigated. Thus some of the apparent temporal variability can be due to cloud level changes. The short term average zonal flow is observed to fluctuate between 80 m/s - 100 m/s at low latitudes while its meridional dependence shows either a weak increase with latitude or near constant magnitude to mid-latitudes and decreasing towards the pole, generally consistent with the profile expected for a vortex circulation. The mean meridional flow is poleward at most latitudes, peaking in mid-latitudes. Higher resolution images with shorter time interval tend to show slightly faster motions of clouds and thus the VMC large scale tracking results should be interpreted with caution. Space time composites of the southern hemisphere images consistently show the presence of hemispheric vortex centered at the south pole.

  20. Communications Transceivers for Venus Surface Missions

    NASA Technical Reports Server (NTRS)

    Force, Dale A.

    2004-01-01

    The high temperature of the surface of Venus poses many difficulties. Previous Venus landers have only operated for short durations before succumbing to the heat. NASA Glenn Research Center conducted a study on communications for long duration Venus surface missions. I report the findings in this presentation. Current technology allows production of communications transceivers that can operate on the surface of Venus, at temperatures above 450 C and pressures of over 90 atmospheres. While these transceivers would have to be relatively simple, without much of the advanced signal processing often used in modern transceivers, since current and near future integrated circuits cannot operate at such high temperatures, the transceivers will be able to meet the requirements of proposed Venus Surface mission. The communication bands of interest are High Frequency or Very High Frequency (HFNHF) for communication between Venus surface and airborne probes (including surface to surface and air to air), and Ultra High Frequency (UHF) to Microwave bands for communication to orbiters. For HFNHF, transceivers could use existing vacuum tube technology. The packaging of the vacuum tubes may need modification, but the internal operating structure already operates at high temperatures. Using metal vacuum structures instead of glass, allows operation at high pressure. Wide bandgap transistors and diodes may be able to replace some of the thermionic components. VHF communications would be useful for line-of- sight operations, while HF would be useful for short-wave type communications using the Venusian ionosphere. UHF and microwave communications use magnetically focused thermionic devices, such as traveling wave tubes (TWTs), magnetron (M-type) amplifiers, and klystrons for high power amplifiers, and backward wave oscillators (BWOs) and reflex klystrons for oscillators. Permanent magnets are already in use in industry that can operate at 500 C. These magnets could focus electron beam tubes on the surface of Venus. While microwave windows will need to be designed for the high pressure, diamond windows have already been demonstrated, so high-pressure microwave windows can be designed and built. Thus, all of these devices could be useful for Venus surface missions. Current electronic power conditioners to supply the high voltages used in these microwave devices cannot operate at high temperatures, but earlier electronic power conditioners that used vacuum tubes can be modified to work at high temperature. Evaluating the various devices in this study, the M-type traveling wave tube (where a traveling wave structure is used in a crossed-field device, similar to the Amplitron used on the Apollo missions) stood out for the high power amplifier since it requires a single high voltage, simplifying the power supply design. Since the receiver amplifier is a low power amplifier, the loss of efficiency in linear beam devices without a depressed collector (and thus needing a single high voltage) is not important; a low noise TWT is a possible solution. Before solid-state microwave amplifiers were available, such TWTs were built with a 1-2 dB noise figure. A microwave triode or transistor made from a wide bandgap material may be preferable, if available. Much of the development work needed for Venusian communication devices will need to focus on the packaging of the devices, and their connections, but the technology is available to build transceivers that can operate on the surface of Venus indefinitely.

  1. Venus Atmospheric Maneuverable Platform Science Mission

    NASA Astrophysics Data System (ADS)

    Polidan, Ronald S.; Lee, Gregory; Ross, Floyd; Sokol, Daniel; Bolisay, Linden

    2015-11-01

    Over the past several years, we have explored a possible new approach to Venus upper atmosphere exploration by applying recent Northrop (non-NASA) development programs and have come up with a new class of exploration vehicle: an atmospheric rover. We will discuss a possible suite of instruments and measurements to study the current climate through detailed characterization of cloud level atmosphere and to understand the processes that control climate on Earth-like planets.Our Venus atmospheric rover concept, the Venus Atmospheric Maneuverable Platform (VAMP), is a hypersonic entry vehicle with an ultra-low ballistic coefficient that transitions to a semi-buoyant air vehicle (AV) after entering the Venus atmosphere. Prior to entry, the AV fully deploys to enable lifting entry and eliminates the need for an aeroshell. The mass savings realized by eliminating the aeroshell allows VAMP to accommodate significantly more instruments compared to previous Venus in situ exploration missions. VAMP targets the global Venus atmosphere between 50–65 km altitudes and would be an ideal, stable platform for atmospheric and surface interaction measurements. We will present a straw man concept of VAMP, including its science instrument accommodation capability and platform’s physical characteristics (mass, power, wingspan, etc). We will discuss the various instrument options.VAMP’s subsonic flight regime starts at ~94 km and after <1 hour, the AV will reach its cruise altitude of ~65 km. During this phase of flight, the VAMP sensor suite will acquire a pre-defined set of upper atmosphere measurements. The nominal VAMP lifetime at cruise altitude is several months to a year, providing numerous circumnavigation cycles of Venus at mid-latitude. The stability of the AV and its extended residence time provide the very long integration times required for isotopic mass analysis. VAMP communicates with the orbiter, which provides data relay and possibly additional science measurements complementing the in situ measurements from the AV. We will specifically focus upon key factors impacting the design and performance of VAMP science.

  2. ESA's Venus Express to reach final destination

    NASA Astrophysics Data System (ADS)

    2006-04-01

    First step: catching Venus To begin to explore our Earth’s hot and hazy sister planet, Venus Express must complete a critical first step, the most challenging one following launch. This involves a set of complex operations and manoeuvres that will inject the spacecraft into orbit. The Venus Orbit Insertion (VOI) manoeuvre allows the spacecraft to reduce its speed relative to Venus, so that it can be captured by the planet’s gravitation. The manoeuvre is a critical one which must proceed at precisely the right place and time. The VOI phase officially started on 4 April and will not be completed until 13 April. It is split into three main sub-phases. The first consists in preparing or initialising the spacecraft for the actual capture manoeuvre so as to avoid the risk of the spacecraft going into safe mode, should parameters unrelated to VOI go off-range. The capture manoeuvre itself consists of a main-engine burn lasting about 50 minutes on the morning of 11 April starting at 09:17 (Central European Summer Time). This is the second main VOI sub-phase. The final sub-phase will be restoring all spacecraft functions, notably resuming communications with Earth and uplinking the commands to be executed during the preliminary ‘capture’ orbit. Orbital capture is controlled by an automatic sequence of predefined commands, uploaded to the spacecraft four days prior to VOI. This sequence is the minimum set needed to perform the main-engine burn. All spacecraft operations are controlled and commanded by the ground control team located at ESA’s European Spacecraft Operations Centre (ESOC) in Darmstadt, Germany. Timeeline of major VOI events (some times subject to change) 4 Aprilacecraft transmitter connected to low gain antenna is switched on. During its interplanetary cruise and during the scientific part of the mission to come, Venus Express communicates with Earth by means of its two high gain antennas. However, during the orbit capture phase (11 April), these two antennas become unusable because of the spacecraft’s required orientation at that time. The low gain antenna, carrying a feeble but instantly recognisable signal, will be transmitting throughout all VOI manoeuvres. This will allow ground controllers to monitor the velocity change during the burn, using NASA’s Deep Space Network’s 70-metre antenna near Madrid, Spain. No other means of communication with the Earth is possible during the capture burn. 5 and 9 April, targeting control manoeuvres. Two time slots are available to adjust course if needed. Given the high accuracy of the course correction performed end of March, Venus Express is currently on the right trajectory for a successful capture into orbit and it is therefore unlikely that either of these two extra slots will be required. 10 to 11 April, final preparations for VOI manoeuvre. 24 to 12 hours before VOI, spacecraft controllers will command Venus Express into its final configuration for the burn. Over the final 12 hours, they will monitor its status, ready to deal with any contingencies requiring last-minute trajectory correction or any revising of the main-engine burn duration. 11 April, 08:03 (CEST), ‘slew’ manoeuvre. This manoeuvre lasts about half an hour and rotates Venus Express so that the main engine faces the direction of motion. Thanks to this, the burn will slow down (rather than accelerate) the spacecraft. 11 April, 09:17 (CEST), main-engine burn starts. A few minutes after firing of the spacecraft thrusters to make sure the propellant settles in the feed lines to the main engine, the latter will begin its 50-minute long burn, ending at 10:07. This thrust will reduce the initial velocity of 29 000 kilometres per hour (in relation to Venus) by 15 percent, allowing capture. Venus Express will settle into its preliminary, elongated nine-day orbit. On capture, it will be at about 120 million kilometres from the Earth and, at its nearest point, within 400 km of the surface of Venus. During the burn, at 09:45 (CEST), Venus Express will disappear behind the planet and will not be visi

  3. High latitude gravity waves at the Venus cloud tops as observed by the Venus Monitoring Camera on board Venus Express

    E-print Network

    Spiga, Aymeric

    High latitude gravity waves at the Venus cloud tops as observed by the Venus Monitoring Camera on board Venus Express A. Piccialli a,b, , D.V. Titov a , A. Sanchez-Lavega c,d , J. Peralta e,f , O September 2013 Available online 25 September 2013 Keywords: Venus Atmospheres, dynamics a b s t r a c t High

  4. Venus Express observations of ULF and ELF waves in the Venus ionosphere: Wave properties and sources

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Leinweber, H.; Hart, R. A.; Wei, H. Y.; Strangeway, R. J.; Zhang, T. L.

    2013-11-01

    Electrical activity in a planetary atmosphere enables chemical reactions that are not possible under conditions of local thermodynamic equilibrium. In both the Venus and terrestrial atmospheres, lightning forms nitric oxide. Despite the existence of an inventory of NO at Venus like the Earth’s, and despite observations of the signals expected from lightning at optical, VLF, and ELF frequencies, the existence of Venus lightning still is met with some skepticism. The Venus Express mission was equipped with a fluxgate magnetometer gradiometer system sampling at rates as high as 128 Hz, and making measurements as low as 200 km altitude above the north polar regions of Venus. However, significant noise levels are present on the Venus Express spacecraft. Cleaning techniques have been developed to remove spacecraft interference at DC, ULF, and ELF frequencies, revealing two types of electromagnetic waves, a transverse right-handed guided mode, and a linearly polarized compressional mode. The propagation of both types of signals is sensitive to the magnetic field in ways consistent with propagation from a distant source to the spacecraft. The linearly polarized compressional waves generally are at lower frequencies than the right-handed transverse waves. They appear to be crossing the usually horizontal magnetic field. At higher frequencies above the lower hybrid frequency, waves cannot enter the ionosphere from below when the field is horizontal. The arrival of signals at the spacecraft is controlled by the orientation of the magnetic field. When the field dips into the atmosphere, the higher frequency guided mode above the lower hybrid frequency can enter the ionosphere by propagating along the magnetic field in the whistler mode. These properties are illustrated with examples from five orbits during Venus Express’ first year in orbit. These properties observed are consistent with the linearly polarized compressional waves being produced at the solar wind interface and the transverse guided waves being produced in the atmosphere.

  5. Thermal structure of Venus nightside upper atmosphere measured by stellar occultations with SPICAV/Venus Express

    NASA Astrophysics Data System (ADS)

    Piccialli, A.; Montmessin, F.; Belyaev, D.; Mahieux, A.; Fedorova, A.; Marcq, E.; Bertaux, J.-L.; Tellmann, S.; Vandaele, A. C.; Korablev, O.

    2015-08-01

    The thermal structure of Venus upper atmosphere (90-140 km) was investigated using stellar occultation measurements acquired by the SPICAV experiment on board Venus Express. The SPICAV ultraviolet channel provides CO2 local density and temperature vertical profiles with a vertical resolution of < 7 km of both the southern and the northern hemispheres on the nightside (18:00-06:00 h local time). A permanent layer of warm air is observed at the mesopause in the altitude range 90-100 km. Temperature then decreases with increasing altitude reaching a minimum value around 125 km. Spatial and temporal changes in the thermal structure have been analyzed. Local time variations dominate the structure of Venus atmosphere at these altitudes: temperatures show an increase of ~ 20 K on the morning side compared to the evening side. The homopause altitude was also determined; it varies between 119 and 138 km of altitude, increasing from the evening side to the morning side. SPICAV temperature profiles were compared to several literature results from ground-based observations, previous spacecraft missions and the Venus Express mission.

  6. 2000 Earth days around Venus: imaging with Venus Monitoring Camera on Venus Express

    NASA Astrophysics Data System (ADS)

    Markiewicz, W. J.; Titov, D.; Ignatiev, N.; Petrova, E.; Khatunatsev, I.; Limaye, S.; Shalygina, O.; Patsaeva, M.; Almeida, M.

    2011-10-01

    By the time of this meeting the Venus Express spacecraft (VEX) should have completed more than 2000, 24 hour orbits around Venus. The Venus Monitoring Camera (VMC) on has been observing the upper cloud layer in four filters in visible spectral range. On average VMC takes nearly two hundred images per day. VEX has a highly elliptical orbit allowing for global as well as close up views with resolution down to 200 meter per pixel. We will review some of the highlights of the results obtained from this enormous data set.

  7. A Few Highlights from Venus Monitoring Camera on Venus Express

    NASA Astrophysics Data System (ADS)

    Markiewicz, Wojciech J.; Titov, D.; Keller, H.; Moissl, R.; Limaye, S.; Ignatiev, N.; Jaumann, R.; Michalik, H.; Thomas, N.

    2008-09-01

    Venus is completely covered by a thick cloud layer whose upper part is composed of sulfuric acid and some unknown aerosols(1). The cloud tops are in fast retrograde rotation (super-rotation), but what is driving this super-rotation is unknown(2). Here we report observations of Venus with the Venus Monitoring Camera3 (VMC) on board the Venus Express spacecraft. Taking advantage of the VMC high resolution imaging and the polar orbit we investigate both global and small scale properties of these clouds, their temporal and latitudinal variations, and derive wind velocities. The Southern polar region is highly variable and can change dramatically on time scales as short as one day, perhaps arising from the injection of SO2 into the mesosphere. The convective cells in the vicinity of the sub-solar point are much smaller than previously inferred(4,5,6), which we interpret as indicating that they are confined to the upper cloud layer, contrary to previous conclusions(7,8), but consistent with more recent study(9). We will also report on surface observations with VMC. (1) Esposito, L.W. et al., in Venus, pp. 484-564, 1983, (2) Limaye, S. S., 2007, J. Geophys. Res., 112, 2007, (3) Markiewicz, W.J. et al., Planet. Space Sci., 55, 1701-1711, 2007, (4) Murray, B.C., et al., Science 183, 1307-1315 (1974), (5) Rossow, W.B. et al., J. Geophys. Res. 85, 8107-8128, 1980, (6) Covey, C.C. and G. Schubert, Nature, 290, 17-20, 1981, (7) Baker II, R.D. and G. Schubert, Nature, 355, 710-712, 1992, (8) Belton, M.J.S. et al., J. Atmos. Sci.. 33, 1394-1417, 1976, (9) Baker, R.D., G. Schubert, and P.W. Jones, J. Geophy. Res., 104, Issue E2, p. 3815-3832, 1999.

  8. A Cubesat Mission to Venus: A Low-Cost Approach to the Investigation of Venus Lightning

    NASA Astrophysics Data System (ADS)

    Majid, W.; Duncan, C.; Kuiper, T.; Russell, C. T.; Hart, R. A.; Lightsey, E.

    2013-12-01

    The occurrence of Venus lightning has been detected by atmospheric probes and landers on Venus; by ionospheric satellites; by an orbiting visible spectrometer; at radio frequencies by the Galileo spacecraft while flying by Venus; and by an Earth-based telescope. However, none of these detectors has enabled us to determine the global occurrence rate of lightning in the atmosphere of Venus, nor the altitude at which this lightning is generated. Such measurements are needed in order to determine the processes that generate Venus lightning and to establish the importance of Venus lightning in controlling the chemical composition of the Venus atmosphere. A simple and affordable mission to perform this mapping could be achieved with CubeSat technology. A mother spacecraft with at least three CubeSat partners using RF detection could map the occurrence of lightning globally and determine its altitude of origin, with triangulation of precisely timed RF event arrivals. Such a mission would provide space for complementary investigations and be affordable under the Discovery mission program. We are embarking on a program to develop CubeSat-based instrumentation for such a mission. The initial task is to develop a lightning detector in a CubeSat development kit using a software defined radio (SDR) operating at decameter wavelengths (5-50 MHz). This involves algorithm development as well as selecting or developing radio hardware for a CubeSat. Two units will be tested on the ground in a lightning zone such as New Mexico, where the Long Wavelength Array operates in the same frequency range. When the concept has been proven, flight subsystems such as solar panels, attitude sensing and communication radios will be added to the CubeSats to test performance in low Earth orbit. Experience gained from flight would enable a cluster of sensors to be proposed for a future Venus mission.

  9. Temporal variations in the cloud cover of Venus as detected from Venus Monitoring Camera Images on Venus Express Orbiter

    NASA Astrophysics Data System (ADS)

    Limaye, S. S.; Markiewicz, W. J.; Krauss, R. J.

    2014-12-01

    The Venus Monitoring Camera (VMC) on Venus Express [1] has been collecting images of the planet since orbit insertion in April 2006 through four narrow band pass (50 nm halfwidth) with center wavelengths of 365, 550, 950 and 1050 nm [2]. With varying range to the planet during the spacecraft's elliptical, near polar orbit, VMC obtains views of the day side southern hemisphere ( ~ 72,500 km) and the limb when it is furthest away from the planet, and can see a fraction of the planet's sun-lit limb northern latitudes when the spacecraft is closer to the planet ( >~ 25,000 km). We use these images to look at the temporal behavior of the normalized intensity and unit slant optical depth (location of the bright limb) at four wavelengths during April 2006 - March 2014. We detect correlated changes in the normalized brightness and the altitude of the unit optical depth over this period. Images were normalized using Minnaert function to account for the varying scattering geometry in order to detect changes in the reflectivity of the cloud cover at selected locations in local solar time. The unit optical depth was determined from the location of the planet's bright limb, taken to be where the brightness gradient is maximum along the bright limb azimuth. The changes observed appear to be quasi periodic. References [1] H. Svedhem,D.V. Titov, F.W. Taylor, O. Witasse, The Venus Express mission, Nature 450, 629-632, 2007. [2] Markiewicz, W. J. et al. Venus monitoring camera for Venus Express. Planet. Space Sci. 55, 1701-1711, 2007.

  10. Venus Express set for launch to the cryptic planet

    NASA Astrophysics Data System (ADS)

    2005-10-01

    On Wednesday, 26 October 2005, the sky over the Baikonur Cosmodrome, Kazakhstan, will be illuminated by the blast from a Soyuz-Fregat rocket carrying this precious spacecraft aloft. The celestial motion of the planets in our Solar System has given Venus Express the window to travel to Venus on the best route. In fact, every nineteen months Venus reaches the point where a voyage from Earth is the most fuel-efficient. To take advantage of this opportunity, ESA has opted to launch Venus Express within the next ‘launch window’, opening on 26 October this year and closing about one month later, on 24 November. Again, due to the relative motion of Earth and Venus, plus Earth’s daily rotation, there is only one short period per day when it is possible to launch, lasting only a few seconds. The first launch opportunity is on 26 October at 06:43 Central European Summer Time (CEST) (10:43 in Baikonur). Venus Express will take only 163 days, a little more than five months, to reach Venus. Then, in April 2006, the adventure of exploration will begin with Venus finally welcoming a spacecraft, a fully European one, more than ten years after humankind paid the last visit. The journey starts at launch One of the most reliable launchers in the world, the Soyuz-Fregat rocket, will set Venus Express on course for its target. Soyuz, procured by the European/Russian Starsem company, consists of three main stages with an additional upper stage, Fregat, atop. Venus Express is attached to this upper stage. The injection of Venus Express into the interplanetary trajectory which will bring it to Venus consists of three phases. In the first nine minutes after launch, Soyuz will perform the first phase, that is an almost vertical ascent trajectory, in which it is boosted to about 190 kilometres altitude by its three stages, separating in sequence. In the second phase, the Fregat-Venus Express ‘block’, now free from the Soyuz, is injected into a circular parking orbit around Earth heading east. This injection is done by the first burn of the Fregat engine, due to take place at 06:52 CEST (04:52 GMT). At 08:03 CEST, about one hour and twenty minutes after lift-off and after an almost full circle around Earth, the third phase starts. While flying over Africa, Fregat will ignite for a second time to escape Earth orbit and head into the hyperbolic trajectory that will bring the spacecraft to Venus. After this burn, Fregat will gently release Venus Express, by firing a separation mechanism. With this last step, the launcher will have concluded its task. Plenty of ground activities for a successful trip Once separated from Fregat at 08:21 CEST, Venus Express will be awoken from its dormant status by a series of automatic on-board commands, such as the activation of its propulsion and thermal control systems, the deployment of solar arrays and manoeuvres to ‘orient’ itself in space. From this moment the spacecraft comes under the control of ESA’s European Space Operations Centre (ESOC) for the full duration of the mission. The flight control team co-ordinate and manage a network of ESA ground stations and antennas around the globe, to regularly communicate with the spacecraft. The New Norcia station in Australia and the Kourou station in French Guiana will in turn communicate with Venus Express in the initial phase of the mission. The first opportunity to receive a signal and confirm that the spacecraft is in good health will be the privilege of the New Norcia station about two hours after launch. In this early phase of the mission, once ESOC has taken full control of the satellite, the spacecraft will be fully activated. Operations will also include two burns of the Venus Express thrusters, to correct any possible error in the trajectory after separation from Fregat. On 28 October, the newly inaugurated Cebreros station in Spain, with its 35-metre antenna, will start to take an active part in ground network operations to relay information between ESOC and the spacecraft. During the cruise phase and once the spacecraft has arrived at Venus,

  11. Mapping Venus: Modeling the Magellan Mission.

    ERIC Educational Resources Information Center

    Richardson, Doug

    1997-01-01

    Provides details of an activity designed to help students understand the relationship between astronomy and geology. Applies concepts of space research and map-making technology to the construction of a topographic map of a simulated section of Venus. (DDR)

  12. The 2010 European Venus Explorer (EVE) mission proposal

    NASA Astrophysics Data System (ADS)

    Wilson, Colin Frank; Chassefière, Eric; Hinglais, Emmanuel; Baines, Kevin H.; Balint, Tibor S.; Berthelier, Jean-Jacques; Blamont, Jacques; Durry, Georges; Ferencz, Csaba S.; Grimm, Robert E.; Imamura, Takeshi; Josset, Jean-Luc; Leblanc, François; Lebonnois, Sebastien; Leitner, Johannes J.; Limaye, Sanjay S.; Marty, Bernard; Palomba, Ernesto; Pogrebenko, Sergei V.; Rafkin, Scot C. R.; Talboys, Dean L.; Wieler, Rainer; Zasova, Liudmila V.; Szopa, Cyrill

    2012-04-01

    The European Venus Explorer (EVE) mission described in this paper was proposed in December 2010 to ESA as an `M-class' mission under the Cosmic Vision programme. It consists of a single balloon platform floating in the middle of the main convective cloud layer of Venus at an altitude of 55 km, where temperatures and pressures are benign (˜25°C and ˜0.5 bar). The balloon float lifetime would be at least 10 Earth days, long enough to guarantee at least one full circumnavigation of the planet. This offers an ideal platform for the two main science goals of the mission: study of the current climate through detailed characterization of cloud-level atmosphere, and investigation of the formation and evolution of Venus, through careful measurement of noble gas isotopic abundances. These investigations would provide key data for comparative planetology of terrestrial planets in our solar system and beyond.

  13. Mission Architecture and Technology Options for a Flagship Class Venus In Situ Mission

    NASA Technical Reports Server (NTRS)

    Balint, Tibor S.; Kwok, Johnny H.; Kolawa, Elizabeth A.; Cutts, James A.; Senske, David A.

    2008-01-01

    Venus, as part of the inner triad with Earth and Mars, represents an important exploration target if we want to learn more about solar system formation and evolution. Comparative planetology could also elucidate the differences between the past, present, and future of these three planets, and can help with the characterization of potential habitable zones in our solar system and, by extension, extrasolar systems. A long lived in situ Venus mission concept, called the Venus Mobile Explorer, was prominently featured in NASA's 2006 SSE Roadmap and supported in the community White Paper by the Venus Exploration Analysis Group (VEXAG). Long-lived in situ missions are expected to belong to the largest (Flagship) mission class, which would require both enabling and enhancing technologies beside mission architecture options. Furthermore, extreme environment mitigation technologies for Venus are considered long lead development items and are expected to require technology development through a dedicated program. To better understand programmatic and technology needs and the motivating science behind them, in this fiscal year (FY08) NASA is funding a Venus Flaghip class mission study, based on key science and technology drivers identified by a NASA appointed Venus Science and Technology Definition Team (STDT). These mission drivers are then assembled around a suitable mission architecture to further refine technology and cost elements. In this paper we will discuss the connection between the final mission architecture and the connected technology drivers from this NASA funded study, which - if funded - could enable a future Flagship class Venus mission and potentially drive a proposed Venus technology development program.

  14. A conceptual venus rover mission using advanced radioisotope power system

    NASA Technical Reports Server (NTRS)

    Evans, Michael; Shirley, James H.; Abelson, Robert Dean

    2006-01-01

    The primary goal of this study is to examine the feasibility of using the novel Advanced RPS-driven Stirling thermoacoustic system to enable extended science operations in the extremely hostile surface environment of Venus. The mission concept entails landing a rover onto the Venus surface, conducting science measurements in different areas on the surface, and returning the science data to Earth. The study focused on developing a rover design to satisfy the science goals with the capability to operate for 60 days. This mission life influences several design parameters, including Earth elevation angle and the maximum communications range to Earth.

  15. Coordinated Hubble Space Telescope and Venus Express Observations of Venus' upper cloud deck

    NASA Astrophysics Data System (ADS)

    Jessup, Kandis Lea; Marcq, Emmanuel; Mills, Franklin; Mahieux, Arnaud; Limaye, Sanjay; Wilson, Colin; Allen, Mark; Bertaux, Jean-Loup; Markiewicz, Wojciech; Roman, Tony; Vandaele, Ann-Carine; Wilquet, Valerie; Yung, Yuk

    2015-09-01

    Hubble Space Telescope Imaging Spectrograph (HST/STIS) UV observations of Venus' upper cloud tops were obtained between 20N and 40S latitude on December 28, 2010; January 22, 2011 and January 27, 2011 in coordination with the Venus Express (VEx) mission. The high spectral (0.27 nm) and spatial (40-60 km/pixel) resolution HST/STIS data provide the first direct and simultaneous record of the latitude and local time distribution of Venus' 70-80 km SO and SO2 (SOx) gas density on Venus' morning quadrant. These data were obtained simultaneously with (a) VEx/SOIR occultation and/or ground-based James Clerk Maxwell Telescope sub-mm observations that record respectively, Venus' near-terminator SO2 and dayside SOx vertical profiles between ?75 and 100 km; and (b) 0.36 ?m VEx/VMC images of Venus' cloud-tops. Updating the (Marcq, E. et al. [2011]. Icarus 211, 58-69) radiative transfer model SO2 gas column densities of ?2-10 ?m-atm and ?0.4-1.8 ?m-atm are retrieved from the December 2010 and January 2011 HST observations, respectively on Venus' dayside (i.e., at solar zenith angles (SZA) < 60°); SO gas column densities of 0.1-0.11 ?m-atm, 0.03-0.31 ?m-atm and 0.01-0.13 ?m-atm are also retrieved from the respective December 28, 2010, January 22, 2011 and January 27, 2011 HST observations. A decline in the observed low-latitude 0.24 and 0.36 ?m cloud top brightness paralleled the declining SOx gas densities. On December 28, 2010 SO2 VMR values ?280-290 ppb are retrieved between 74 and 81 km from the HST and SOIR data obtained near Venus' morning terminator (at SZAs equal to 70° and 90°, respectively); these values are 10× higher than the HST-retrieved January 2011 near terminator values. Thus, the cloud top SO2 gas abundance declined at all local times between the three HST observing dates. On all dates the average dayside SO2/SO ratio inferred from HST between 70 and 80 km is higher than that inferred from the sub-mm the JCMT data above 84 km confirming that SOx photolysis is more efficient at higher altitudes. The direct correlation of the SOx gases provides the first clear evidence that SOx photolysis is not the only source for Venus' 70-80 km sulfur reservoir. The cloud top SO2 gas density is dependent in part on the vertical transport of the gas from the lower atmosphere; and the 0.24 ?m cloud top brightness levels are linked to the density of the sub-micron haze. Thus, the new results may suggest a correlation between Venus' cloud-top sub-micron haze density and the vertical transport rate. These new results must be considered in models designed to simulate and explore the relationship between Venus' sulfur chemistry cycle, H2SO4 cloud formation rate and climate evolution. Additionally, we present the first photochemical model that uniquely tracks the transition of the SO2 atmosphere from steady to non-steady state with increasing SZA, as function of altitude within Venus' mesosphere, showing the photochemical and dynamical basis for the factor of ?2 enhancements in the SOx gas densities observed by HST near the terminator above that observed at smaller SZA. These results must also be considered when modeling the long-term evolution of Venus' atmospheric chemistry and dynamics.

  16. Nuclear Electric Propulsion Application: RASC Mission Robotic Exploration of Venus

    NASA Technical Reports Server (NTRS)

    McGuire, Melissa L.; Borowski, Stanley K.; Packard, Thomas W.

    2004-01-01

    The following paper documents the mission and systems analysis portion of a study in which Nuclear Electric Propulsion (NEP) is used as the in-space transportation system to send a series of robotic rovers and atmospheric science airplanes to Venus in the 2020 to 2030 timeframe. As part of the NASA RASC (Revolutionary Aerospace Systems Concepts) program, this mission analysis is meant to identify future technologies and their application to far reaching NASA missions. The NEP systems and mission analysis is based largely on current technology state of the art assumptions. This study looks specifically at the performance of the NEP transfer stage when sending a series of different payload package point design options to Venus orbit.

  17. Venus

    NASA Technical Reports Server (NTRS)

    1995-01-01

    VENUS CLOUD TOPS VIEWED BY HUBBLE. This is a NASA Hubble Space Telescope ultraviolet-light image of the planet Venus, taken on January 24 1995, when Venus was at a distance of 70.6 million miles (113.6 million kilometers) from Earth. Venus is covered with clouds made of sulfuric acid, rather than the water-vapor clouds found on Earth. These clouds permanently shroud Venus' volcanic surface, which has been radar mapped by spacecraft and from Earth-based telescope. At ultraviolet wavelengths cloud patterns become distinctive. In particular, a horizontal 'Y'-shaped cloud feature is visible near the equator. Similar features were seen from Mariner 10, Pioneer Venus, and Galileo spacecrafts. This global feature might indicate atmospheric waves, analogous to high and low pressure cells on Earth. Bright clouds toward Venus' poles appear to follow latitude lines. The polar regions are bright, possibly showing a haze of small particles overlying the main clouds. The dark regions show the location of enhanced sulfur dioxide near the cloud tops. From previous missions, astronomers know that such features travel east to west along with the Venus' prevailing winds, to make a complete circuit around the planet in four days. Because Venus is closer to the Sun than Earth, the planet appears to go through phases, like the Moon. When Venus swings close to Earth the planet's disk appears to grow in size, but changes from a full disk to a crescent. The image was taken with the Wide Field Planetary Camera-2, in PC mode. False color has been used enhance cloud features.

  18. Thermal structure of Venus night-side upper atmosphere from SPICAV/SOIR Venus Express occultations

    NASA Astrophysics Data System (ADS)

    Piccialli, Arianna; Mahieux, Arnaud; Belyaev, Denis; Bertaux, Jean-Loup; Fedorova, Anna; Marcq, Emmanuel; Vandaele, Ann C.; Montmessin, Franck; Korablev, Oleg; Wilquet, Valérie

    Venus upper atmosphere (70-170 km altitude) is one of the most intriguing regions on the planet. It corresponds to a transition region characterized by a complex dynamics and circulation: strong retrograde zonal winds dominate the lower mesosphere while a solar-to-antisolar (SSA) circulation driven by a day-to-night temperature gradient can be observed in the upper mesosphere/lower thermosphere (Schubert et al., 2007). CO_2 density and temperature profiles of Venus upper atmosphere have been measured from both ground-based (Clancy et al., 2012; Rengel et al., 2008; Sonnabend et al., 2012) and spacecraft missions (Taylor et al., 1980; Seiff et al., 1980; Zasova et al., 2007). The thermal structure of Venus upper mesosphere/lower thermosphere shows a significant variability both on day-to-day as well as longer timescales. More recently, a layer of warm air has been detected at altitudes of 90-120 km on the nightside both by SPICAV/SOIR (Bertaux et al., 2007; Mahieux et al., 2012) and by ground-based (Rengel et al., 2008) observations. The SPICAV/SOIR (Spectroscopy for the investigation of the characteristics of the atmosphere of Venus) instrument has been operating on board the ESA orbiting platform Venus Express since 2006. In the stellar occultation mode the ultraviolet channel provides CO_2 local density and temperature vertical profiles with a vertical resolution of < 7 km of both the Southern and the Northern hemispheres on the night side (6 pm to 6 am local time). A permanent warm area appears distinctly at the mesopause at about 90 - 100 km of altitude; the temperature then decreases with increasing altitude reaching a minimum value around 125 km. Spatial and temporal changes in the thermal structure have been analyzed. Local time variations dominate the structure of Venus atmosphere at these altitudes: temperatures show an increase of about 20 K on the morning side compared to the evening side. The homopause altitude is also determined; it varies between 119 and 138 km of altitude, showing no dependence on the latitude or local time. SPICAV/SOIR solar occultation observations sound the Venus atmosphere at the terminator (limit between the day and night sides of the planet). SOIR performs routine observations of the 70 - 170 km region, at latitudes extending from pole to pole. From its measurement of the CO_2 density, temperature can be derived using the hydrostatic equilibrium. Results from both channels (UV and SOIR) of SPICAV will be presented and discussed.

  19. European Venus Explorer: An in-situ mission to Venus using a balloon platform

    NASA Astrophysics Data System (ADS)

    Chassefière, E.; Korablev, O.; Imamura, T.; Baines, K. H.; Wilson, C. F.; Titov, D. V.; Aplin, K. L.; Balint, T.; Blamont, J. E.; Cochrane, C. G.; Ferencz, Cs.; Ferri, F.; Gerasimov, M.; Leitner, J. J.; Lopez-Moreno, J.; Marty, B.; Martynov, M.; Pogrebenko, S. V.; Rodin, A.; Whiteway, J. A.; Zasova, L. V.; the EVE Team

    2009-07-01

    Planetary balloons have a long history already. A small super-pressure balloon was flown in the atmosphere of Venus in the eighties by the Russian-French VEGA mission. For this mission, CNES developed and fully tested a 9 m diameter super-pressure balloon, but finally replaced it by a smaller one due to mass constraints (when it was decided to send Vega to Halley's Comet). Furthermore, several kinds of balloons have been proposed for planetary exploration [Blamont, J., in: Maran, S.P. (Ed.), The Astronomy and Astrophysics Encyclopedia. Cambridge University Press, p. 494, 1991]. A Mars balloon has been studied for the Mars-94 Russian-French mission, which was finally cancelled. Mars and Venus balloons have also been studied and ground tested at JPL, and a low atmosphere Venus balloon is presently under development at JAXA (the Japanese Space Agency). Balloons have been identified as a key element in an ongoing Flagship class mission study at NASA, with an assumed launch date between 2020 and 2025. Recently, it was proposed by a group of scientists, under European leadership, to use a balloon to characterize - by in-situ measurements - the evolution, composition and dynamics of the Venus atmosphere. This balloon is part of a mission called EVE (European Venus Explorer), which has been proposed in response to the ESA AO for the first slice of the Cosmic Vision program by a wide international consortium including Europe, Russia, Japan and USA. The EVE architecture consists of one balloon platform floating at an altitude of 50-60 km, one short lived probe provided by Russia, and an orbiter with a polar orbit to relay data from the balloon and probe, and to perform remote sensing science observations. The balloon type preferred for scientific goals is one, which would oscillate in altitude through the cloud deck. To achieve this flight profile, the balloon envelope would contain a phase change fluid. While this proposal was not selected for the first slice of Cosmic Vision missions, it was ranked first among the remaining concepts within the field of solar system science.

  20. Venus Express Contributions to the Study of Planetary Lightning

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Hart, R. A.; Zhang, T. L.

    2014-04-01

    Jupiter, and Saturn are expected to generate the electrical potential differences in their clouds sufficient to cause a breakdown in the atmosphere,creating a conducting path for the electric potential to discharge. This high-energy phenomenon creates a hot, high-pressure channel that enables chemical reactions not possible under usual local thermodynamic conditions. Thus it is of some interest to determine if lightning occurs in an atmosphere. While Venus is not usually considered one of the wet planets, lightning has been an object of interest since the Venera landers. It was observed with electromagnetic coils on Venera 11, 12, 13, 14 landers [2]. It was observed with a visible spectrometer on the Venera 9 orbits [1]. It was mapped during solar occultations by the electric antenna on the Pioneer Venus Orbiter [4]. These measurements revealed extensive lightning activity with an electromagnetic energy flux similar to that on Earth. However, the observations were limited in number in the atmosphere and to the nightside from orbit. In order to improve the understanding of Venus lightning, the Venus Express magnetometer was given a 128-Hz sampling rate that could cover much of the ELF frequencies at which lightning could be observed in the weak magnetic fields of the Venus ionosphere [5]. This investigation was immediately successful [3], but mastering the cleaning of the broadband data took several years to accomplish. Furthermore, the high polar latitudes of VEX periapsis were not the ideal locations to conduct the more global survey that was desired. Fortunately, after precessing poleward over the first few years the latitude of periapsis has returned to lower latitudes(Figures 1 and 2) and active electrical storms are now being studied. The charged constituent of the Venus atmosphere need not be water. In fact, we believe it is H2SO4 which polarizes much as water does and which freezes and melts at similar temperatures. If it is H2SO4, we would expect the constituent to be sensitive to the rate of Venus volcanism releasing sulfur and sulfur dioxide into the atmosphere. This is one correlation we are anxious to pursue on future missions.

  1. Tracking Clouds on Venus using Venus Express Data

    NASA Astrophysics Data System (ADS)

    Pertzborn, Rosalyn; Limaye, Sanjay; Markiewicz, Wojciech; Jasmin, Tommy; Udgaonkar, Nishant

    2014-05-01

    In the US, a growing emphasis has been placed on the development of inclusive and authentic educational experiences which promote active participation by the K-12 learning community as well as the general public in NASA's earth and space science research activities. In the face of growing national and international budgetary constraints which present major challenges across all scientific research organizations around the world, the need for scientific communities to dramatically improve strategies for effective public engagement experiences, demonstrating the relevance of earth and space science research contributions to the citizenry, have become paramount. This presentation will provide an introduction to the online Venus Express Cloud tracking applet, an overview of feedback from educational users based on classroom/pilot implementation efforts, as well as the concept's potential viability for the promotion of expanded public participation in the analysis of data in future planetary exploration and research activities, nationally and internationally. Acknowledgements: We wish to acknowledge the contributions of Mr. Nishant Udgaonkar, a summer intern with the S.N. Bose Scholars Program, sponsored by the Science and Engineering Board, Department of Science and Technology, Government of India, the Indo-U.S. Science and Technology Forum, and the University of Wisconsin-Madison. We also wish to acknowledge the Space Science and Engineering Center as well as NASA for supporting this project.

  2. MESSENGER and Venus Express Observations of the Solar Wind Interaction with Venus: A Dual Spacecraft Study

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Acuna, M. H.; Anderson, B. J.; Barabash, S.; Benna, M.; Boardsen, S. A.; Fraenz, M.; Gloeckler, G.; Gold, R. E.; Ho, G. C.; Korth, H.; Krimigis, S. M.; McNutt, R. L., Jr.; Raines, J. M.; Sarantos, M.; Solomon, S. C.; Zhang, T.; Zurbuchen, T. H.

    2007-01-01

    At 23:08 UT on 5 June 2007 the MESSENGER spacecraft reached its closest approach altitude (338 krn) during its second flyby of Venus en route to its 201 1 orbit insertion at Mercury. Whereas no measurements were collected during MESSENGER'S first Venus flyby in October 2006, the Magnetometer (MAG) and the Energetic Particle and Plasma Spectrometer (EPPS) operated successfully throughout this second encounter. Venus provides the solar system's best example to date of a solar wind - ionosphere planetary interaction. Pioneer Venus Orbiter measurements have shown that this interaction affects the upper atmosphere and ionosphere down to altitudes of - 150 km. Here we present an initial overview of the MESSENGER observations during the - 4 hrs that the spacecraft spent within 10 planet radii of Venus and, together with Venus Express measurements, examine the influence of solar wind plasma and interplanetary magnetic field conditions on the solar wind interaction at solar minimum.

  3. An Atmospheric Variability Model for Venus Aerobraking Missions

    NASA Technical Reports Server (NTRS)

    Tolson, Robert T.; Prince, Jill L. H.; Konopliv, Alexander A.

    2013-01-01

    Aerobraking has proven to be an enabling technology for planetary missions to Mars and has been proposed to enable low cost missions to Venus. Aerobraking saves a significant amount of propulsion fuel mass by exploiting atmospheric drag to reduce the eccentricity of the initial orbit. The solar arrays have been used as the primary drag surface and only minor modifications have been made in the vehicle design to accommodate the relatively modest aerothermal loads. However, if atmospheric density is highly variable from orbit to orbit, the mission must either accept higher aerothermal risk, a slower pace for aerobraking, or a tighter corridor likely with increased propulsive cost. Hence, knowledge of atmospheric variability is of great interest for the design of aerobraking missions. The first planetary aerobraking was at Venus during the Magellan mission. After the primary Magellan science mission was completed, aerobraking was used to provide a more circular orbit to enhance gravity field recovery. Magellan aerobraking took place between local solar times of 1100 and 1800 hrs, and it was found that the Venusian atmospheric density during the aerobraking phase had less than 10% 1 sigma orbit to orbit variability. On the other hand, at some latitudes and seasons, Martian variability can be as high as 40% 1 sigmaFrom both the MGN and PVO mission it was known that the atmosphere, above aerobraking altitudes, showed greater variability at night, but this variability was never quantified in a systematic manner. This paper proposes a model for atmospheric variability that can be used for aerobraking mission design until more complete data sets become available.

  4. Monday, March 23, 2009 SPECIAL SESSION: VENUS ATMOSPHERE

    E-print Network

    Rathbun, Julie A.

    Monday, March 23, 2009 SPECIAL SESSION: VENUS ATMOSPHERE: VENUS EXPRESS AND FUTURE MISSIONS 2:30 p Y. J. Daniels J. T. M. Barabash S. Zhang T. L. Venus Express: Atmospheric Loss and Electrodynamics [#1408] The solar wind interaction with Venus is eroding the Venus atmosphere in several different ways

  5. Venus Interior Structure Mission (VISM): Establishing a Seismic Network on Venus

    NASA Technical Reports Server (NTRS)

    Stofan, E. R.; Saunders, R. S.; Senske, D.; Nock, K.; Tralli, D.; Lundgren, P.; Smrekar, S.; Banerdt, B.; Kaiser, W.; Dudenhoefer, J.

    1993-01-01

    Magellan radar data show the surface of Venus to contain a wide range of geologic features (large volcanoes, extensive rift valleys, etc.). Although networks of interconnecting zones of deformation are identified, a system of spreading ridges and subduction zones like those that dominate the tectonic style of the Earth do not appear to be present. In addition, the absence of a mantle low-viscosity zone suggests a strong link between mantle dynamics and the surface. As a natural follow-on to the Magellan mission, establishing a network of seismometers on Venus will provide detailed quantitative information on the large scale interior structure of the planet. When analyzed in conjunction with image, gravity, and topography information, these data will aid in constraining mechanisms that drive surface deformation.

  6. IN-SITU AERIAL EXPLORATION OF VENUS BY BALLOON -SCIENCE OBJECTIVES AND MISSION ARCHITECTURE. K.H. Baines1

    E-print Network

    Treiman, Allan H.

    IN-SITU AERIAL EXPLORATION OF VENUS BY BALLOON - SCIENCE OBJECTIVES AND MISSION ARCHITECTURE. K the trailblazing flights of the 1985 twin Soviet VEGA balloons, missions to fly in the skies of Venus have been of the recently-completed Venus Flagship Mission study. Such missions will answer fundamental science issues

  7. MESSENGER and Venus Express Observations of the Solar Wind Interaction with Venus

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Acuna, Mario H.; Anderson, Brian J.; Barabash, Stas; Benna, Mehdi; Boardsen, Scott A.; Fraenz, Markus; Gloeckler, George; Gold, Robert E.; Ho,George C.; Korth, Haje; Krimigis, Stamatios M.; McNutt, Ralph L., Jr.; Raines, Jim M.; Sarantos, Menelaos; Solomon, Sean C.; Zhang, Tielong; Zurbuchen, Thomas H.

    2009-01-01

    At 23:08 UTC on 5 June 2007 the MESSENGER spacecraft reached its closest approach altitude of 338 kin during its final flyby of Venus en route to its 2011 orbit insertion at Mercury. The availability of the simultaneous Venus Express solar wind and interplanetary magnetic field measurements provides a rare opportunity to examine the influence of upstream conditions on this planet's solar wind interaction. We present MESSENGER observations of new features of the Venus - solar wind interaction including hot flow anomalies upstream of the bow shock, a flux rope in the near-tail and a two-point determination of the timescale for magnetic flux transport through this induced magnetosphere. Citation: Stavin, J. A., et al. (2009), MESSENGER and Venus Express observations of the solar wind interaction with Venus,

  8. Morphology of the Venus clouds from the imaging by Venus Monitoring Camera onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Titov, D. V.; Markiewicz, W. J.; Moissl, R.; Ignatiev, N.; Limaye, S.; Khatuntsev, I.; Roatsch, Th.; Almeida, M.

    2008-09-01

    For more than 2 years Venus Monitoring Camera onboard ESA's Venus Express collects images of Venus from global views with resolution of ~50 km to close-up snapshots resolving features of about few hundreds meters. The UV filter is centered at a characteristic wavelength of the unknown UV absorber (365 nm) and allows one to study morphology of the cloud tops that bears the information about dynamical process and distribution of the UV absorber. Low latitudes (< 40 deg) are dominated by relatively dark clouds that have mottled and fragmented appearance clearly indicating convective activity in the sub-solar region. At ~50 degrees latitude this pattern gives way to streaky clouds suggesting that horizontal flow prevails here. Poleward from ~60 degrees the planet is covered by almost featureless bright polar hood sometimes crossed by dark thin (~300 km) spiral or circular structures. This global cloud pattern changes on time scales of few days resulting in so called "brightening events" when the bright haze can extend far into low latitudes. Cloud pattern shows remarkable diurnal variability. Afternoon sector of the planet has strongly developed traces of turbulence in contrast to the atmosphere in the morning. Also the bright hood extends further to low latitudes in the morning than in the evening. We will present latitudinal, diurnal, and temporal variations based on two years of VMC observations. Imaging of streaky clouds in the middle and high latitudes provides a tool to study the wind pattern. We will also present preliminary results on the cloud streaks orientation derived from the VMC images.

  9. The Ninevah Mission: A design summary for an unmanned mission to Venus, volume 1

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The design summary for an unmanned mission to the planet Venus, with code name Ninevah, is presented. The design includes a Hohmann transfer trajectory analysis, propulsion trade study, an overview of the communication and instrumentation systems, power requirements, probe and lander analysis, and a weight and cost analysis.

  10. Temporal variations of UV reflectivity of Venus observed by the Venus Monitoring Camera onboard Venus Express.

    NASA Astrophysics Data System (ADS)

    Lee, Yeon Joo; Imamura, Takeshi; Schroder, Stefan

    The UV channel of the Venus Monitoring Camera (VMC) onboard Venus Express (VEX) detects dark and bright features at the cloud top level all over the globe. This UV contrast is affected by the abundance of an unknown UV absorber, which is located within the upper cloud layer, and the upper haze above the cloud tops (Pollack et al.,1979; Esposito, 1980). The unknown UV absorber is a major sink of solar energy in the Venus middle atmosphere (Crisp, 1986). The upper haze and clouds take part in sulfur photochemical processes in the Venus mesosphere (Mills et al., 2007). At the cloud top altitude the zonal wind speed is highest, resulting in changes in cloud morphology in a few days. Therefore, the features shown in the UV images are diagnostic for atmospheric dynamics and chemistry. By analyzing VMC UV images, we found there is a clear decreasing trend of the global mean albedo by 20-30% over 2000 orbits (=2000 Earth days) of VEX operation. This decrease is driven by changes at high latitudes. This implies that the typical latitudinal albedo distribution, bright polar hood and dark equatorial region, varies over time. The latitudinal difference in albedo changes from a clear brightness gradient from pole to equator to an almost identical brightness in both regions. Interestingly, this temporal variation is similar to that of the SO2 abundance above the cloud tops, observed in the same period (Marcq et al., 2013). This suggests a reduction of SO2 over the equator decreases the amount of upper haze at high latitudes, as less sulfur is supplied by the meridional circulation. We investigate the phase angle dependence of the latitudinal albedo difference, which reveals that the vertical distribution of the UV absorbers and the upper haze varies in time as well. Our results show large scale variations in Venusian atmospheric dynamics near the cloud tops, represented by temporal changes in the amount of upper haze at high latitudes and/or in the vertical distribution of the unknown UV absorber.

  11. Venus Express en route to probe the planet's hidden mysteries

    NASA Astrophysics Data System (ADS)

    2005-11-01

    Venus Express will eventually manoeuvre itself into orbit around Venus in order to perform a detailed study of the structure, chemistry and dynamics of the planet's atmosphere, which is characterised by extremely high temperatures, very high atmospheric pressure, a huge greenhouse effect and as-yet inexplicable "super-rotation" which means that it speeds around the planet in just four days. The European spacecraft will also be the first orbiter to probe the planet's surface while exploiting the "visibility windows" recently discovered in the infrared waveband. The 1240 kg mass spacecraft was developed for ESA by a European industrial team led by EADS Astrium with 25 main contractors spread across 14 countries. It lifted off onboard a Soyuz-Fregat rocket, the launch service being provided by Starsem. The lift-off from the Baikonur Cosmodrome in Kazakstan this morning took place at 09:33 hours local time (04:33 Central European Time). Initial Fregat upper-stage ignition took place 9 minutes into the flight, manoeuvring the spacecraft into a low-earth parking orbit. A second firing, 1 hour 22 minutes later, boosted the spacecraft to pursue its interplanetary trajectory. Contact with Venus Express was established by ESA's European Space Operations Centre (ESOC) at Darmstadt, Germany approximately two hours after lift-off. The spacecraft has correctly oriented itself in relation to the sun and has deployed its solar arrays. All onboard systems are operating perfectly and the orbiter is communicating with the Earth via its low-gain antenna. In three days' time, it will establish communications using its high-gain antenna. Full speed ahead for Venus Venus Express is currently distancing itself from the Earth full speed, heading on its five-month 350 million kilometre journey inside our solar system. After check-outs to ensure that its onboard equipment and instrument payload are in proper working order, the spacecraft will be mothballed, with contact with the Earth being reduced to once daily. If needed, trajectory correction manoeuvres can go ahead at the half-way stage in January. When making its closest approach, Venus Express will face far tougher conditions than those encountered by Mars Express on nearing the Red Planet. For while Venus's size is indeed similar to that of the Earth, its mass is 7.6 times that of Mars, with gravitational attraction to match. To resist this greater gravitational pull, the spacecraft will have to ignite its main engine for 53 minutes in order to achieve 1.3 km/second deceleration and place itself into a highly elliptical orbit around the planet. Most of its 570 kg of propellant will be used for this manoeuvre. A second engine firing will be necessary in order to reach final operational orbit: a polar elliptical orbit with 12-hour crossings. This will enable the probe to make approaches to within 250 km of the planet's surface and withdraw to distances of up to 66 000 km, so as to carry out close-up observations and also get an overall perspective. Exploring other planets to better understand planet Earth "The launch of Venus Express is a further illustration of Europe's determination to study the various bodies in our solar system", stressed Professor David Southwood, the Director of ESA's science programmes. "We started in 2003 with the launch of Mars Express to the Red Planet and Smart-1 to the Moon and both these missions have amply exceeded our expectations. Venus Express marks a further step forward, with a view to eventually rounding off our initial overview of our immediate planetary neighbours with the BepiColombo mission to Mercury to be launched in 2013." "With Venus Express, we fully intend to demonstrate yet again that studying the planets is of vital importance for life here on Earth", said Jean Jacques Dordain, ESA Director General. "To understand climate change on Earth and all the contributing factors, we cannot make do with solely observing our own planet. We need to decipher the mechanics of the planetary atmosphere in

  12. Cloud level winds from the Venus Express Monitoring Camera imaging

    NASA Astrophysics Data System (ADS)

    Khatuntsev, I. V.; Patsaeva, M. V.; Titov, D. V.; Ignatiev, N. I.; Turin, A. V.; Limaye, S. S.; Markiewicz, W. J.; Almeida, M.; Roatsch, Th.; Moissl, R.

    2013-09-01

    Six years of continuous monitoring of Venus by European Space Agency’s Venus Express orbiter provides an opportunity to study dynamics of the atmosphere our neighbor planet. Venus Monitoring Camera (VMC) on-board the orbiter has acquired the longest and the most complete so far set of ultra violet images of Venus. These images enable a study the cloud level circulation by tracking motion of the cloud features. The highly elliptical polar orbit of Venus Express provides optimal conditions for observations of the Southern hemisphere at varying spatial resolution. Out of the 2300 orbits of Venus Express over which the images used in the study cover about 10 Venus years. Out of these, we tracked cloud features in images obtained in 127 orbits by a manual cloud tracking technique and by a digital correlation method in 576 orbits. Total number of wind vectors derived in this work is 45,600 for the manual tracking and 391,600 for the digital method. This allowed us to determine the mean circulation, its long-term and diurnal trends, orbit-to-orbit variations and periodicities. We also present the first results of tracking features in the VMC near-IR images. In low latitudes the mean zonal wind at cloud tops (67 ± 2 km following: Rossow, W.B., Del Genio, A.T., Eichler, T. [1990]. J. Atmos. Sci. 47, 2053-2084) is about 90 m/s with a maximum of about 100 m/s at 40-50°S. Poleward of 50°S the average zonal wind speed decreases with latitude. The corresponding atmospheric rotation period at cloud tops has a maximum of about 5 days at equator, decreases to approximately 3 days in middle latitudes and stays almost constant poleward from 50°S. The mean poleward meridional wind slowly increases from zero value at the equator to about 10 m/s at 50°S and then decreases to zero at the pole. The error of an individual measurement is 7.5-30 m/s. Wind speeds of 70-80 m/s were derived from near-IR images at low latitudes. The VMC observations indicate a long term trend for the zonal wind speed at low latitudes to increase from 85 m/s in the beginning of the mission to 110 m/s by the middle of 2012. VMC UV observations also showed significant short term variations of the mean flow. The velocity difference between consecutive orbits in the region of mid-latitude jet could reach 30 m/s that likely indicates vacillation of the mean flow between jet-like regime and quasi-solid body rotation at mid-latitudes. Fourier analysis revealed periodicities in the zonal circulation at low latitudes. Within the equatorial region, up to 35°S, the zonal wind show an oscillation with a period of 4.1-5 days (4.83 days on average) that is close to the super-rotation period at the equator. The wave amplitude is 4-17 m/s and decreases with latitude, a feature of the Kelvin wave. The VMC observations showed a clear diurnal signature. A minimum in the zonal speed was found close to the noon (11-14 h) and maxima in the morning (8-9 h) and in the evening (16-17 h). The meridional component peaks in the early afternoon (13-15 h) at around 50°S latitude. The minimum of the meridional component is located at low latitudes in the morning (8-11 h). The horizontal divergence of the mean cloud motions associated with the diurnal pattern suggests upwelling motions in the morning at low latitudes and downwelling flow in the afternoon in the cold collar region.

  13. A Statistical Study of Lightning Occurrence Rates from Venus Express Observations

    NASA Astrophysics Data System (ADS)

    Hart, R. A.; Russell, C. T.; Zhang, T.

    2014-12-01

    Venus Express has now recorded ELF emissions (up to 64 Hz) in the low-altitude Venus ionosphere since mid-2006. These signals are most prevalent when the ionosphere magnetic field dips into the atmosphere, enabling the electromagnetic signal to enter the ionosphere. The signals can extend over the full bandwidth of the instrument, up to 64 Hz. The waves are nearly circularly polarized and are right-hand polarized, as expected for whistler-mode propagation generated by lightning. When isolated bursts of signal occur, dispersion is seen in which the high-frequency waves arrive first. This is the expected signature generated by impulsive electric discharges. These observations suggest that the rate of lightning occurrence on Venus is not unlike the terrestrial rate where atmosphere chemistry is affected measurably by these discharges. When Venus Express was inserted into its 24-hour elliptical polar orbit, periapsis was near 80 degrees and later precessed up to 88 degrees. Now in the orbit, Venus Express has precessed over the pole and has reached lower latitudes than on arrival. The spacecraft is in the final stages of its 8 year mission and reaching the lowest latitudes yet. In this study we present statistics of lightning-associated ELF signals from recent observations spanning more than 3 Venus years.

  14. European Venus Explorer (EVE): an in-situ mission to Venus

    NASA Astrophysics Data System (ADS)

    Chassefière, E.; Korablev, O.; Imamura, T.; Baines, K. H.; Wilson, C. F.; Titov, D. V.; Aplin, K. L.; Balint, T.; Blamont, J. E.; Cochrane, C. G.; Ferencz, Cs.; Ferri, F.; Gerasimov, M.; Leitner, J. J.; Lopez-Moreno, J.; Marty, B.; Martynov, M.; Pogrebenko, S. V.; Rodin, A.; Whiteway, J. A.; Zasova, L. V.; Michaud, J.; Bertrand, R.; Charbonnier, J.-M.; Carbonne, D.; Raizonville, P.

    2009-03-01

    The European Venus Explorer (EVE) mission was proposed to the European Space Agency in 2007, as an M-class mission under the Cosmic Vision Programme. Although it has not been chosen in the 2007 selection round for programmatic reasons, the EVE mission may serve as a useful reference point for future missions, so it is described here. It consists of one balloon platform floating at an altitude of 50-60 km, one descent probe provided by Russia, and an orbiter with a polar orbit which will relay data from the balloon and descent probe, and perform science observations. The balloon type preferred for scientific goals is one which oscillates in altitude through the cloud deck. To achieve this flight profile, the balloon envelope contains a phase change fluid, which results in a flight profile which oscillates in height. The nominal balloon lifetime is 7 days—enough for one full circumnavigation of the planet. The descent probe’s fall through the atmosphere takes 60 min, followed by 30 min of operation on the surface. The key measurement objectives of EVE are: (1) in situ measurement from the balloon of noble gas abundances and stable isotope ratios, to study the record of the evolution of Venus; (2) in situ balloon-borne measurement of cloud particle and gas composition, and their spatial variation, to understand the complex cloud-level chemistry; (3) in situ measurements of environmental parameters and winds (from tracking of the balloon) for one rotation around the planet, to understand atmospheric dynamics and radiative balance in this crucial region. The portfolio of key measurements is complemented by the Russian descent probe, which enables the investigation of the deep atmosphere and surface.

  15. European Venus Explorer : an in-situ mission to Venus using a balloon platform

    NASA Astrophysics Data System (ADS)

    Chassefiere, Eric

    The European Venus Explorer (EVE) mission was proposed to the European Space Agency in 2007, as an M-class mission under the Cosmic Vision Programme. Although it has not been chosen in the 2007 selection round for programmatic reasons, the EVE mission may serve as a useful reference point for future missions, so it is described here. It consists of one balloon platform floating at an altitude of 50-60 km, one descent probe provided by Russia, and an orbiter with a polar orbit which will relay data from the balloon and descent probe, and perform science observations. The balloon type preferred for scientific goals is one which oscillates in altitude through the cloud deck. To achieve this flight profile , the balloon envelope contains a phase change fluid, which results in a flight profile which oscillates in height. The nominal balloon lifetime is 7 days - enough for one full circumnavigation of the planet. The descent probe's fall through the atmosphere takes 60 minutes, followed by 30 minutes of operation on the surface. The key measurement objectives of EVE are: (i) in situ measurement from the balloon of noble gas abundances and stable isotope ratios , to study the record of the evolution of Venus; (ii) in situ balloon-borne measurement of cloud particle and gas composition, and their spatial variation, to understand the complex cloud-level chemistry; (iii) in situ measurements of environmental parameters and winds (from tracking of the balloon) for one rotation around the planet, to understand atmospheric dynamics and radiative balance in this crucial region. The portfolio of key measurements is complemented by the Russian descent probe, which enables the investigation of the deep atmosphere and surface.

  16. Aerocapture Performance Analysis of A Venus Exploration Mission

    NASA Technical Reports Server (NTRS)

    Starr, Brett R.; Westhelle, Carlos H.

    2005-01-01

    A performance analysis of a Discovery Class Venus Exploration Mission in which aerocapture is used to capture a spacecraft into a 300km polar orbit for a two year science mission has been conducted to quantify its performance. A preliminary performance assessment determined that a high heritage 70 sphere-cone rigid aeroshell with a 0.25 lift to drag ratio has adequate control authority to provide an entry flight path angle corridor large enough for the mission s aerocapture maneuver. A 114 kilograms per square meter ballistic coefficient reference vehicle was developed from the science requirements and the preliminary assessment s heating indicators and deceleration loads. Performance analyses were conducted for the reference vehicle and for sensitivity studies on vehicle ballistic coefficient and maximum bank rate. The performance analyses used a high fidelity flight simulation within a Monte Carlo executive to define the aerocapture heating environment and deceleration loads and to determine mission success statistics. The simulation utilized the Program to Optimize Simulated Trajectories (POST) that was modified to include Venus specific atmospheric and planet models, aerodynamic characteristics, and interplanetary trajectory models. In addition to Venus specific models, an autonomous guidance system, HYPAS, and a pseudo flight controller were incorporated in the simulation. The Monte Carlo analyses incorporated a reference set of approach trajectory delivery errors, aerodynamic uncertainties, and atmospheric density variations. The reference performance analysis determined the reference vehicle achieves 100% successful capture and has a 99.87% probability of attaining the science orbit with a 90 meters per second delta V budget for post aerocapture orbital adjustments. A ballistic coefficient trade study conducted with reference uncertainties determined that the 0.25 L/D vehicle can achieve 100% successful capture with a ballistic coefficient of 228 kilograms per square meter and that the increased ballistic coefficient increases post aerocapture V budget to 134 meters per second for a 99.87% probability of attaining the science orbit. A trade study on vehicle bank rate determined that the 0.25 L/D vehicle can achieve 100% successful capture when the maximum bank rate is decreased from 30 deg/s to 20 deg/s. The decreased bank rate increases post aerocapture delta V budget to 102 meters per second for a 99.87% probability of attaining the science orbit.

  17. Ionospheric Modulation of Venus Express Lightning Detection Rates

    NASA Astrophysics Data System (ADS)

    Hart, Richard A.; Russell, Christopher T.; Zhang, Tielong

    2015-11-01

    Venus Express completed its nearly 9 year campaign at Earth’s sister planet in late 2014. During this period the onboard fluxgate magnetometer collected data up to 64 Hz in frequency while near periapsis. This is the expected frequency range for lightning-generated whistler-mode waves at Venus, between the local electron and ion gyrofrequencies. These waves are right-hand circularly polarized and are guided by the local magnetic field. When the Venusian ionopause is low enough in altitude to reside in the collisional region, the interplanetary magnetic field can get carried down with the ions and magnetize the lower ionosphere. As the field travels towards the terminator it gains a radial component, enabling whistlers to reach higher altitudes and be detected by the spacecraft. The mission covered almost an entire solar cycle and frequently observed a magnetized ionosphere during the solar minimum phase when the ionosphere was weak due to reduced incident EUV. Detection was most common at 250 km altitude where the waves travel more slowly due to reduced ionospheric density. In response they increase in amplitude in order to conserve magnetic energy flux. Here, we examine the changes in the ionospheric properties associated with the evolution of the solar cycle and the rate of detection of these lightning-generated signals.

  18. Climate change on Venus and future spacecraft mission priorities

    NASA Astrophysics Data System (ADS)

    Bullock, M.; Grinspoon, D.

    Weathering of surface minerals in the sulfur-rich lower atmosphere of Venus may well have played a significant role in the recent evolution of the planet's climate. SO 2 in the atmosphere is interesting because it is the primary precursor of Venus' bright H 2SO 4 /H 2O clouds, it is a greenhouse gas, it is most likely outgassed by volcanoes [Prinn, 1985], it probably reacts with the surface, and it is apparently much higher in abundance that would be expected from thermochemical equilibrium with the surface [Fegley and Treiman, 1992] (although interpretations of Vega 1 and 2 UV spectrometer data challenge the latter, see Bertaux et al., [1996]). Changes in the atmospheric abundance of SO 2 would be accompanied by alterations in the optical properties of the clouds and in the greenhouse effect, thereby affecting surface temperatures [Bullock and Grinspoon, 2001]. Fegley and Prinn , [1989] demonstrated e perimentally that the reaction CaCO3 +x SO 2 ==> CaSO 4 + CO proceeds rapidly under Venus-like conditions, and concluded that SO 2 and hence the H 2 SO 4 /H 2O clouds would disappear in 1.9 My unless SO 2 in the atmosphere were continually replenished by volcanic outgassing. Using a coupled chemical kinetic reaction-diffusion and climate model, [ Bullock and Grinspoon, 2001] calculated that volcanism must supply SO 2 to the atmosphere on approximately 30 My timescales in order to maintain clouds with their current optical properties. Clues to the nature of the recent Venus climate may be obtained by elucidating the sensitivity of cloud properties to changes in a mospheric SO 2 andt H 2O and by investigations into the styles and depths of chemical weathering at the surface. Future robotic spacecraft missions have the pot ential to provide significant insights into recent climate change on Venus and on the role that sulfur may have played. Among the most important and scientifically valuable investigations are: 1. High spectral, spatial, and temporal resolution near-IR i aging spectrometrym from Venus orbit in order to retrieve accurate SO 2, H 2O and CO abundances and variability beneath the clouds. Coupling gas abundance and variability to cloud morphology , cloud optical properties, and to atmospheric dynamics would enable a far better understanding of how clouds and climate respond to changing atmospheric chemistry. 2. Visible to near-IR high resolution images of the surface from 15-20 km in order to complement the global synthetic aperture radar imagery of the Magellan mission (e.g. [M o r o z, 2002]). Remaining scientific issues about Venus' geologic history, which is vigorously debated, may well be resolved by obtaining near-visual wavelength datasets of selected areas on Venus. These can be used to calibrate the global radar dataset in terms of surface properties and geomorphology. 3. Elemental and mineralogical analyses of the surface and subsurface, in order to establish both fundamental mineralogy and weathering products as a function of depth. Visual images of the surface by the Venera landers clearly show broken slabs a few cm in thickness [S u r k o v et al., 1984]. This provides hints as to the nature and extent of weathering of the surface. A detailed mineralogy of the top 10 cm of the surface would provide highly valuable information on the nature and rates of surface-atmosphere interactions and their possible role in alterations of atmospheric chemistry and climate. Although Venus is a difficult planet to study because of its shroud of sulfuric acid clouds and its otherwise harsh environment, it is the only planet that shares the similarity with Earth of having a climate that is actively modified by its geology . As the study of Earth's climate becomes of greater and greater significance to society, so too does the necessity of thinking of planetary climate 'outside the box'. The continued exploration of Venus is one of the most promising avenues to accomplish this. Bertaux, J.L., et al., J. Geophys. Res. , 101 , 12,709-12,745, 1996. Bullock, M.A., and D.H. Grinspoon, Icarus, 150 , 19-37, 2001. Fegley,

  19. First Results from Venus Express Aerobraking Campaign

    NASA Astrophysics Data System (ADS)

    Svedhem, Håkan

    After a very successful mission orbiting Venus for more than 8 years, slowly the fuel is running out and the spacecraft will inevitably end up in the hot and acid atmosphere of the planet. Before this will happen we are taking the opportunity to dip down to around 130 km in a controlled manner in order to make detailed in situ investigations of this for remote sensing instruments difficult to access region. The spacecraft will use an aerobraking technique which maximizes the atmospheric drag by placing the solar panels perpendicular to the flight direction and will benefit from the inherent dynamically stable configuration this will provide. The on board accelerometers will give a direct measurement of the deceleration which in turn is directly proportional to the local atmospheric density. This will provide an excellent way to study both the total density profile and small scale density variations in the region of the pericentre. At the time of this campaign the pericentre will be located near the terminator at about 75 degrees Northern latitude. Aerobraking is a very efficient method of reducing the pericentre velocity and thereby reducing the apocentre altitude and the orbital period. Using this technique missions otherwise not feasible due to mass and fuel constraints can be enabled. This will be the first time an ESA spacecraft will be used for aerobraking and therefore it is run on an experimental basis as only limited resources are available. The so called “walk-in” phase will start at 190 km altitude on 17 May and the campaign ends on 11 July. Depending on the atmospheric densities encountered the orbital period may be reduced with up to 30 minutes. This presentation will report on the initial findings from this aerobraking campaign.

  20. The EvolVe mission concept - unveiling the evolution of Venus

    NASA Astrophysics Data System (ADS)

    Koronczay, D.; Bailey, R.; Bertone, S.; Credendino, S.; Kleinschneider, A. M.; Lanzky, M.; ?osiak, A.; Marcenat, C.; Martin, P.; Muñoz Elorza, I.; Neidhart, T.; Rexer, M.; Wirnsberger, H.

    2015-10-01

    Venus and Earth are similar in size, bulk composition and distance from the Sun; both are located within the habitable zone. Nevertheless, their surface conditions reveal that they are two very different worlds; Venus, unlike Earth, cannot support life on its surface.The aim of this mission is to determine how and why Venus evolved so differently by exploring its past and present geologic activity. The concept was designed by young scientists and engineers during Alpbach Summer School 2014.

  1. Mariner Venus-Mercury 1973 project. Volume 2: Extended mission-Mercury 2 and 3 encounters

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The Mariner Venus/Mercury 1973 mission operations Extended Mission is described. The activities are summarized from shortly after Mercury I through the end of mission. The operational activities are reported by Mission Operations Systems functions providing a brief summary from each discipline. Based on these experiences recommendations for future projects are made.

  2. VERITAS: A mission to study the highest priority Decadal Survey questions for Venus

    NASA Astrophysics Data System (ADS)

    Smrekar, S. E.; Elkins-Tanton, L. T.; Hensley, S.; Campbell, B. A.; Gilmore, M. S.; Phillips, R. J.; Zebker, H. A.

    2014-12-01

    The Venus Emissivity, Radio Science, InSAR, Topography And Spectroscopy (VERITAS) Mission, a proposed NASA Discovery mission, seeks to produce high-resolution altimetry and synthetic aperture radar (SAR) imaging, thermal emissivity, and an improved gravity field. VERITAS addresses the highest priority Decadal survey questions: 1) Did Venus host ancient aqueous environments? 2) Can understanding the roles of physics, chemistry, geology, and dynamics in driving planetary atmospheres lead to a better understanding of climate change on Earth? 3) How have chemical and physical processes operated, interacted, and evolved? Using an interferometric mapping radar, a near infrared spectrometer, and radio science experiment, VERITAS will examine 1) the similarity of tessera plateau formation to continents on Earth, 2) the current forces driving tectonics and volcanism, and, perhaps most importantly, 3) inform our understanding of how stagnant lid planets evolve. Data from VIRTIS on Venus Express show that the highly deformed tessera plateaus, possible remnants of a prior regime on Venus, may be more felsic in composition than the surrounding plains, supporting the hypothesis they are similar to Earth's continents. However this interpretation is equivocal due to uncertainty in the available altimetry. VERITAS is designed to collect data with sufficient resolution to answer this question definitively, and also aid in the assessment of tesserae as a touchdown point for a future lander. Similarly, the enormous rift zones and mountain belts are manifestations of global scale tectonics within the last billion years on Venus, but present data are not adequate to determine the driving forces or whether they are presently active. VERITAS will provide such data through fine-resolution topographic maps and, if possible, measurements of any current-day crustal deformation. Finally, current data are highly suggestive of recent and active volcanism. VERITAS observations can tell us if current volcanism is limited to mantle plume heads or is more widespread. The geologic setting of present day volcanism or tectonism also holds lessons for predicting activity on Earth-sized planets elsewhere in the galaxy. Together these investigations allow us to assess just how similar or dissimilar the evolution of Venus and Earth has been.

  3. Interplanetary mission design handbook. Volume 1, part 1: Earth to Venus ballistic mission opportunities, 1991-2005

    NASA Technical Reports Server (NTRS)

    Sergeyevsky, A. B.; Yin, N. H.

    1983-01-01

    Graphical data necessary for the preliminary design of ballistic missions to Venus is presented. Contours of launch energy requirements, as well as many other launch and arrival parameters, are presented in launch data/arrival date space for all launch opportunities from 1991 through 2005. An extensive text is included which explains mission design methods, from launch window development to Venus probe and orbiter arrival design, utilizing the graphical data in this volume as well as numerous equations relating various parameters.

  4. Water vapor near Venus cloud tops from VIRTIS-H/Venus express observations 2006-2011

    NASA Astrophysics Data System (ADS)

    Cottini, V.; Ignatiev, N. I.; Piccioni, G.; Drossart, P.

    2015-08-01

    This work aims to give a summary of the water vapor at the cloud top of Venus atmosphere using the complete set of observations made using high spectral resolution channel (-H) of Visible and Infrared Thermal Imaging Spectrometer (VIRTIS), on board the ESA Venus Express orbiter, to measure the cloud top altitude and the water vapor abundance near this level. An initial analysis of these measurements by Cottini et al. (2012) was limited to data in 140 orbits in the period 2007-2008. These observations were limited to the Northern hemisphere due to observational geometry in this early part of the mission. In the present paper, the analysis is extended to a larger dataset covering the years 2006-2011, significantly improving the latitudinal coverage. Altitude of the cloud tops, corresponding to unit optical depth at a wavelength of 2.5 ?m, is equal to 69±1 km at low latitudes, and decreases toward the pole to 62-64 km. The water vapor abundance is equal to 3±1 ppm in low latitudes and it increases reaching a maximum of 5±2 ppm at 70-80° of latitude in both hemispheres, with a sharp drop in the polar regions. This can be explained by the specific dynamics of the atmosphere of Venus affecting the distribution of water vapor such as the transfer of water vapor in the Hadley cell and the dynamic in the polar vortex. The average height of the cloud tops and the H2O near this level are symmetric with respect to the equator. As a function of local solar time, the water vapor shows no particular dependence, and the cloud tops exhibit just a weak maximum around noon. Over 5 years of observations the average values of the cloud top altitude and the water vapor were quite stable in low and middle latitudes, while in high latitudes both quantities in 2009-2011 years are systematically higher than in 2006-2008. Short period variations increasing with latitude are observed, from approximately less than ±1 km for cloud tops and ±1 ppm for water vapor in low latitudes to, respectively, ±2 km and ±2 ppm in high latitudes. As a rule there is no correlation between variations of the cloud top altitude, the water vapor content, and the UV brightness. However, numerous examples can be found when UV dark features, with a characteristic size of a few degrees of latitude (several hundred kilometers), coincide with regions of higher cloud tops.

  5. The Scientific Exploration of Venus

    NASA Astrophysics Data System (ADS)

    Taylor, Fredric W.

    2014-12-01

    Part I. Views of Venus, from the Beginning to the Present Day: 1. The dawn of Venus exploration; 2. Mariner and Venera; 3. Pioneer Venus and Vega: orbiters, balloons and multi-probes; 4. Images of the surface; 5. The forgotten world; 6. Earth-based astronomy delivers a breakthrough; 7. Can't stop now; 8. Europe and Japan join in: Venus Express and Akatsuki; Part II. The Motivation to Continue the Quest: 9. Origin and evolution: the solid planet; 10. Atmosphere and ocean; 11. A volcanic world; 12. The mysterious clouds; 13. Superwinds and polar vortices; 14. The climate on Venus, past, present and future; 15. Could there be life on Venus?; Part III. Plans and Visions for the Future: 16. Solar system exploration; 17. Coming soon to a planet near you: planned Venus missions; 18. Towards the horizon: advanced technology; 19. Beyond the horizon: human expeditions; Epilogue; Appendix A. Chronology of space missions to Venus; Appendix B. Data about Venus.

  6. Collapse of Venus' polar thermosphere density as detected by Venus Express.

    NASA Astrophysics Data System (ADS)

    Rosenblatt, P.; Bruinsma, S.; Müller-Wodarg, I. C. F.; Svedhem, H.; Häusler, B.

    2011-10-01

    The Venus Express (VEX) spacecraft offers the opportunity to probe in-situ the density of the polar atmosphere of Venus at altitude range between 165- 185 km. Two methods have been used to derive the density at dedicated campaigns of the Venus Express Atmospheric Drag Experiment (VExADE). The first method uses the tracking data of the spacecraft to precisely compute the drag acceleration of its motion when passing through the thermosphere at the periapsis pass of its orbit [1]. The second method uses the inertial wheels on board the spacecraft to measure the torque generated by the atmospheric drag during the periapsis pass [2]. Both methods provide reliable and similar estimates of the density at the periapsis pass. The estimated density from the first three campaigns is about 2-3 times lower than the one predicted from available empirical models. It suggests either polar collapse of the thermospheric structure or colder thermospheric temperatures than predicted by the models.

  7. Vital problems of Venus geology - Outlook for their resolution by Magellan and post-Magellan missions

    NASA Astrophysics Data System (ADS)

    Bazilevskii, Aleksandr T.

    1990-12-01

    Five areas of study considered to be vital for progress in Venus geology are detailed, and their relevance to Magellan and post-Magellan missions is discussed. These issues include the study of the general style of endogenetic activity of Venus; the major geochemical types of crust material on Venus; the character and intensity of exogenic processes; and the structure of Venus' interior and its seismicity. It is established that the first two areas of inquiry will enjoy decisive advances from Magellan data. It is suggested that, while the third and fourth areas of study will benefit from data obtained through the Magellan mission, the establishment of a program of post-Magellan missions would provide additional vital information.

  8. Long-term variations of the UV contrast on Venus observed by the Venus Monitoring Camera on board Venus Express

    NASA Astrophysics Data System (ADS)

    Lee, Y. J.; Imamura, T.; Schröder, S. E.; Marcq, E.

    2015-06-01

    We analyze the Venus ultraviolet (UV) reflectivity as observed by the Venus Monitoring Camera on board Venus Express over 2000 orbits in the years 2006-2011. We compare several laws for the photometric correction of global images of Venus, and find that the combined law of Lambert and Lommel-Seeliger is most suitable for our study. Our analysis of the corrected images reveals strong fluctuations in the reflectivity contrast between low and high latitude regions of up to 40%, that follow variations of the SO2 abundance above the cloud top. Additionally, the phase angle dependence of the contrast gradually change from weak to strong, which may be related with the vertical distribution of the unknown UV absorber and the overlaying upper haze layer. We suggest that these variations result from a combination of two processes. One is the meridional transport of SO2, which forms sulfuric acid aerosol particles at high latitudes. The other is the presence of vertical winds near the cloud top level, which control the vertical mixing of the unknown UV absorber and the upper haze.

  9. An orbital radar mapper of Venus in the 1980's - Mission design and analysis

    NASA Technical Reports Server (NTRS)

    Asnin, S. K.

    1973-01-01

    A reasonable approach to the examination of Venus topography, obscured for photographic imaging, is available in the application of airborne radar mapping systems to an orbiter mission about the planet. Extrapolating the improving capabilities of earth-based radar study of Venus into the 1980's suggests that only a non-uniform, poorly resolved surface profile will be possible relative to the potential for 100% coverage at 100 meter resolution with an orbital radar. The intent of this paper is to define mission opportunities favorable for a Venus orbital mapper during the 1980's, to examine orbit design problem associated with mapping radar systems, to establish what flexibility exists for an adaptive mapping strategy, to contribute to the sizing of particular spacecraft systems, to suggest a reference mission design and demonstrate mission feasibility.

  10. Retrieval of Venus' clouds parameters with polarization using SPICAV-IR onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Rossi, Loïc; Marcq, Emmanuel; Montmessin, Franck; Fedorova, Anna; Stam, Daphne; Bertaux, Jean-Loup; Korablev, Oleg

    2015-04-01

    Understanding the structure and dynamics of Venus' clouds is essential as they have a strong impact on the radiative balance and atmospheric chemistry of the planet. Polarimetry has greatly contributed to our knwoledge about the properties of the cloud layers located between 48 and ~ 70 km. Hansen and Hovenier (1974), using ground-based observations, found the cloud particles to be ~ 1?m spherical droplets, with a refractive index corresponding to a concentrated sulfuric acid-water solution. Later, Kawabata et al. (1980), using polarimetric data from OCPP onboard Pioneer Venus retrieved the properties of the haze: effective radius of ~ 0.25?m, refractive indices consistent with a sulfuric acid-water solution, variance of the particle size distribution. We introduce here new measurements obtained with the SPICAV-IR spectrometer onboard ESA's Venus Express. Observing Venus in the visible and IR from 650 nm to 1625 nm with a good spatial and temporal converage, SPICAV's sensitivity to the degree of linear polarization gives us an opportunity to put better constraints on haze and cloud particles at Venus cloud top, as well as their spatial and temporal variability. These observations reveal a particular feature called glory, observed by SPICAV-IR and VMC (Markiewicz et al. 2014). Using a radiative transfer code taking into account polarization (de Haan et al. 1987, de Rooij et al. 1984, Stam et al. 1999), we model the cloud layers and the glory allowing us to retrieve the real part of the refractive index, the effective radius and variance of the particle size distribution from the main cloud layer. Our results confirm that the particles are spherical, with a narrow size distribution and with refractive indices that are compatible with H2SO4-H2O solutions (Rossi et al. 2014). Using the large latitudinal coverage of the data, we can also retrieve the variation of the overlying haze layer optical thickness. We find that ?h is increasing with increasing latitude, in agreement with previous measurements from Braak et al. (2002) and Knibbe et al. (1997). References Hansen, J. E. and Hovenier, J. W., 1974, Interpretation of the polarization of Venus., Journal of Atmospheric Sciences, 31. Kawabata et al., 1980, Cloud and haze properties from Pioneer Venus Polarimetry, J. Geophys. Res., 85. Markiewicz, W.J. et al., 2014, Glory on venus cloud tops and the unknown UV absorber, Icarus, 234. de Haan, J. F. et al, 1987, The adding method for multiple scattering calculations of polarized light, Astron. Astrophys., 183. de Rooij, W. A. and van der Stap, C. C. A. H., 1984, Expansion of Mie scattering matrices in generalized spherical functions, Astron. Astrophys., 131 Stam, D. M. et al., 1999, Degree of linear polarization of light emerging from the cloudless atmosphere in the oxygen A band, J. Geophys. Res., 104. Rossi, L. et al., 2014, Preliminary study of Venus cloud layers with polarimetric data from SPICAV/VEx, Planet. Space Sci., In Press. Braak, C. J. et al., 2002, Spatial and temporal variations of Venus haze properties obtained from Pioneer Venus Orbiter polarimetry, J. Geophys. Res. (Planets), 107. Knibbe, W. J. J. et al., 1997,A biwavelength analysis of Pioneer Venus polarization observations, J. Geophys. Res., 102.

  11. PC-403: Pioneer Venus multiprobe spacecraft mission operational characteristics document, volume 2

    NASA Technical Reports Server (NTRS)

    Barker, F. C.

    1978-01-01

    The data handling subsystem, command subsystem, communications subsystem, power subsystem, and mission operations of the Pioneer Venus multiprobe are presented. The multiprobe spacecraft performance in normal operating modes that correspond to the performance of specific functions at the time of specific events in the mission is described.

  12. Lunar and Planetary Science XXXV: Venus

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Venus" included the following reports:Preliminary Study of Laser-induced Breakdown Spectroscopy (LIBS) for a Venus Mission; Venus Surface Investigation Using VIRTIS Onboard the ESA/Venus Express Mission; Use of Magellan Images for Venus Landing Safety Assessment; Volatile Element Geochemistry in the Lower Atmosphere of Venus; Resurfacing Styles and Rates on Venus: Assessment of 18 Venusian Quadrangles; Stereo Imaging of Impact Craters in the Beta-Atla-Themis (BAT) Region, Venus; Depths of Extended Crater-related Deposits on Venus ; Potential Pyroclastic Deposit in the Nemesis Tessera (V14) Quadrangle of Venus; Relationship Between Coronae, Regional Plains and Rift Zones on Venus, Preliminary Results; Coronae of Parga Chasma, Venus; The Evolution of Four Volcano/Corona Hybrids on Venus; Calderas on Venus and Earth: Comparison and Models of Formation; Venus Festoon Deposits: Analysis of Characteristics and Modes of Emplacement; Topographic and Structural Analysis of Devana Chasma, Venus: A Propagating Rift System; Anomalous Radial Structures at Irnini Mons, Venus: A Parametric Study of Stresses on a Pressurized Hole; Analysis of Gravity and Topography Signals in Atalanta-Vinmara and Lavinia Planitiae Canali are Lava, Not River, Channels; and Formation of Venusian Channels in a Shield Paint Substrate.

  13. Hydrogen halides measurements in the Venus mesosphere retrieved from SOIR on board Venus express

    NASA Astrophysics Data System (ADS)

    Mahieux, A.; Wilquet, V.; Vandaele, A. C.; Robert, S.; Drummond, R.; Chamberlain, S.; Grau Ribes, A.; Bertaux, J. L.

    2015-08-01

    The SOIR instrument on board Venus Express regularly sounds the Venus mesosphere using the solar occultation technique. Densities and volume mixing ratios of HCl and HF are measured in the 70-115 km and 75-110 km altitude region respectively, at the Venus terminator. All latitudes from pole to pole are covered. In this work, we study the latitude and long-term variations of the volume mixing ratio (VMR) of HCl, and the long-term time trend of HF, from June 2006 to February 2013. This period of time corresponds to approximately eleven Venusian years. Large variations in the VMR profiles are observed, mostly on the short-term. Both hydrogen halides present unforeseen positive exponential gradients of their VMR with pressure, which shows time and latitude variations. Long-term trends on the whole period of the HCl VMR are also observed at certain pressure levels in the equatorial and polar regions. HF also presents a time dependence of its VMR at certain pressure levels. Results are compared to previous HCl and HF VMR observations. The ability of SOIR to target both H35Cl and H37Cl isotopologues has also been investigated. Numerous concomitant density profiles lead to the determination of the 37Cl/35Cl isotopic ratio on Venus, found to be equal to 0.34±0.13, which is compatible with the value found on Earth.

  14. Venus

    NASA Astrophysics Data System (ADS)

    Fegley, B., Jr.

    Venus is Earth's nearest planetary neighbor and has fascinated mankind since the dawn of history. Venus' clouds reflect most of the sunlight shining on the planet and make it the brightest object in the sky after the Sun and Moon. Venus is visible with the naked eye as an evening star until a few hours after sunset or as a morning star shortly before sunrise. Many ancient civilizations observed and worshipped Venus, which had a different name in each society, for example, Ishtar to the Babylonians, Aphrodite to the Greeks, Tai'pei to the Chinese, and Venus to the Romans. Venus has continued to play an important role in myth, literature, and science throughout history.

  15. Venus Express Publications Supported by NASA Last update: 06-16-2015

    E-print Network

    Rathbun, Julie A.

    1 Venus Express Publications Supported by NASA Last update: 06-16-2015 Compiled by Kevin H. Baines Venus Express funding 2006 Baines, K. H. Atreya, S., Carlson, R. W., Crisp, D., Drossart, P., Formisano, V., Limaye, S. S., Markiewicz, W. J., and Piccioni, G. (2006). To the depths of Venus: Exploring

  16. Venus

    ERIC Educational Resources Information Center

    Martin, Paula; Stofan, Ellen

    2004-01-01

    On 8 June 2004 Venus will pass in front of the Sun as seen from the Earth. Many people will watch the small dark dot cross the solar disk, but will they stop to think about Venus as a real place? In this article we discuss what we know about Venus, what it looks like from orbit, what you might see if you were on the surface and future plans for…

  17. An orbital radar mapper of venus in the 1980's: Mission design and analysis

    NASA Technical Reports Server (NTRS)

    Asnin, S. K.

    1973-01-01

    The examination of Venus topography, obscured for photographic imaging, is reported in the application of airborne radar mapping systems to an orbiter mission about the planet. Extrapolating the improving capabilities of earth-based radar study of Venus into the 1980's is reported which suggests that only a non-uniform, poorly resolved surface profile will be possible relative to the potential for 100% coverage at 100 meter resolution with an orbital radar. The intent of this paper is: to define mission opportunities favorable for a Venus orbital mapper during the 1980's, to examine orbit design problems associated with mapping radar systems, to establish with flexibility exists for an adaptive mapping strategy, to contribute to the sizing of particular spacecraft systems, and to suggest a reference mission design and demonstrate feasibility.

  18. Pioneer Venus: Report of a study by the Science Steering Group, June 1972. [concerning 1976, 77, 78 and 80 missions

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The 1976/77 multiple probe mission of the Pioneer Venus spacecraft is discussed, along with the 1978 and 1980 missions. Various questions about Venus are answered; velocities and temperatures expected in the atmosphere, atmospheric chemistry, magnetic measurements, and model atmospheres are included.

  19. Optical properties of the Venus upper clouds from the data obtained by Venus Monitoring Camera on-board the Venus Express

    NASA Astrophysics Data System (ADS)

    Shalygina, O. S.; Petrova, E. V.; Markiewicz, W. J.; Ignatiev, N. I.; Shalygin, E. V.

    2015-08-01

    During more than 6 years of the Venus Express (VEx) mission, the Venus Monitoring Camera (VMC) took around 300 000 images in four channels covering almost all the latitudes, including night and day sides. Here we give an overview of the VMC data and summarize results of retrievals of the optical properties of the Venus upper clouds. The in-flight characterization and calibration of VMC are also described. We model the phase dependence of brightness (phase range ? = 0 - 140 °) retrieved from the dayside images obtained in NIR1 VMC channel at various latitudes (30°N-60°S) and local solar times (6-18 h). The radiative transfer calculations were performed for the plane-parallel atmospheric layers, and the Mie theory was used for the calculations of the single scattering phase functions of the cloud aerosols. The size distribution of cloud particles and their refractive index were estimated for each of the regions observed. These retrievals show some temporal and spatial variations. In general, the particles at low latitudes are somewhat larger than in the regions closer to the southern pole (Reff = 1.2 - 1.4 ?mversus 0.9 - 1.05 ?m). At latitudes 40°S-60°S the refractive index is usually smaller than in the other regions (mr = 1.44 - 1.45versus 1.45-1.47 with sporadic spikes of up to 1.49). The retrievals robustly show presence of particles with a radius of about Reff = 0.9 ?m in the clouds and/or the haze above them in these mid-latitudes. Small submicron (Reff = 0.23 ?m) particles are detected mostly in the morning.

  20. Navigation Support at JPL for the JAXA Akatsuki (PLANET-C) Venus Orbiter Mission

    NASA Technical Reports Server (NTRS)

    Ryne, Mark S.; Mottinger, Neil A.; Broschart, Stephen B.; You, Tung-Han; Higa, Earl; Helfrich, Cliff; Berry, David

    2011-01-01

    This paper details the orbit determination activities undertaken at JPL in support of the Japanese Aerospace Exploration Agency's (JAXA) Akatsuki (a.k.a. Plan-et-C and/or Venus Climate Orbiter) mission. The JPL navigation team's role was to provide independent navigation support as a point of comparison with the JAXA generated orbit determination solutions. Topics covered include a mis-sion and spacecraft overview, dynamic forces modeling, cruise and approach or-bit determination results, and the international teaming arrangement. Significant discussion is dedicated to the events surrounding recovery from the unsuccessful Venus orbit insertion maneuver.

  1. Venus Exploration Themes August 2014

    E-print Network

    Rathbun, Julie A.

    Venus Exploration Themes August 2014 #12;ii Venus Exploration Themes Prepared in order to preserve extracts from the March 2012 Venus Exploration Goals and Objectives and the October 2009 Venus Exploration................................................................................................................... 1 1. FIFTY YEARS OF VENUS MISSIONS

  2. Venus Express observations of atmospheric oxygen escape during the passage of several coronal mass ejections

    E-print Network

    California at Berkeley, University of

    Venus Express observations of atmospheric oxygen escape during the passage of several coronal mass of Venus atmospheric constituents, especially oxygen, by direct antisunward acceleration of planetary ions may have played a key role in Venus' atmosphere evolution, but the significance of their effects

  3. On the magnetic configuration near Venus: EOF modeling and statistical analyses based on Venus Express measurements

    NASA Astrophysics Data System (ADS)

    He, M.; Vogt, J.; Zhang, T.; Rong, Z.

    2015-10-01

    More than 2000 orbits of Venus Express magnetic field measurementsare used for Orthogonal Function (EOF) analysis to study and model the magnetic environment over the Venus northern polar cap. The modeling results extract the dominant coherent variations, separate the known physical phenomenaon different EOFs and identify the most important driving factors. EOF1 represents the magnetic draping configuration of IMF Bz component whereas EOF2 is controlled by IMF By component and presents the draping and piling-up of IMF By. Besides, our analysis illustrates an asymmetric response of magnetic By component to IMF between the ±E hemispheres,constricted over the terminator (about 90-93° Solar Zeniths Angle) below 300km altitude. The magnetic By component increases as the increase of the parallel IMF component in the +E hemisphere but antiparallel IMF component the -E. To detail the asymmetry, we define a new coordinate system referring to the Sun-Venus-VEX plane which is more robust in comparison with the SVE or VSO coordinate system, and develop a new data averaging method which balances the significance and resolution of data representation.Our result suggests the asymmetry is neither resulting from a large plane of current nor a line of current.

  4. Rotational temperatures of Venus upper atmosphere as measured by SOIR on board Venus Express

    NASA Astrophysics Data System (ADS)

    Mahieux, A.; Vandaele, A. C.; Robert, S.; Wilquet, V.; Drummond, R.; López Valverde, M. A.; López Puertas, M.; Funke, B.; Bertaux, J. L.

    2015-08-01

    SOIR is a powerful infrared spectrometer flying on board the Venus Express spacecraft since mid-2006. It sounds the Venus atmosphere above the cloud layer using the solar occultation technique. In the recorded spectra, absorption structures from many species are observed, among them carbon dioxide, the main constituent of the Venus atmosphere. Previously, temperature vertical profiles were derived from the carbon dioxide density retrieved from the SOIR spectra by assuming hydrostatic equilibrium. These profiles show a permanent cold layer at 125 km with temperatures of ~100 K, surrounded by two warmer layers at 90 and 140 km, reaching temperatures of ~200 K and 250-300 K, respectively. In this work, temperature profiles are derived from the SOIR spectra using another technique based on the ro-vibrational structure of carbon dioxide observed in the spectra. The error budget is extensively investigated. Temperature profiles obtained by both techniques are comparable within their respective uncertainties and they confirm the vertical structure previously determined from SOIR spectra.

  5. Venus mesospheric sulfur dioxide measurement retrieved from SOIR on board Venus Express

    NASA Astrophysics Data System (ADS)

    Mahieux, A.; Vandaele, A. C.; Robert, S.; Wilquet, V.; Drummond, R.; Chamberlain, S.; Belyaev, D.; Bertaux, J. L.

    2015-08-01

    SOIR on board Venus Express sounds the Venus upper atmosphere using the solar occultation technique. It detects the signature from many Venus atmosphere species, including those of SO2 and CO2. SO2 has a weak absorption structure at 4 ?m, from which number density profiles are regularly inferred. SO2 volume mixing ratios (VMR) are calculated from the total number density that are also derived from the SOIR measurements. This work is an update of the previous work by Belyaev et al. (2012), considering the SO2 profiles on a broader altitude range, from 65 to 85 km. Positive detection VMR profiles are presented. In 68% of the occultation spectral datasets, SO2 is detected. The SO2 VMR profiles show a large variability up to two orders of magnitude, on a short term time scales. We present mean VMR profiles for various bins of latitudes, and study the latitudinal variations; the mean latitude variations are much smaller than the short term temporal variations. A permanent minimum showing a weak latitudinal structure is observed. Long term temporal trends are also considered and discussed. The trend observed by Marcq et al. (2013) is not observed in this dataset. Our results are compared to literature data and generally show a good agreement.

  6. The Water Vapor Abundance Near the Surface of Venus from Venus Express / VIRTIS Observations

    NASA Astrophysics Data System (ADS)

    Bezard, Bruno; Tsang, C. C. C.; Carlson, R. W.; Piccioni, G.; Marcq, E.; Drossart, P.; VIRTIS/Venus Express Team

    2008-09-01

    We present an analysis of Venus Express/VIRTIS observations of the 1.18-?m window on Venus' night side. We used the infrared M-channel of the VIRTIS instrument, an imaging spectrometer for the range 1-5 ?m with a resolution of about 17 nm. The 1.18-?m window probes down to the surface and allows us to map and monitor the water abundance in the lowest scale height of the atmosphere. Besides CO2 and H2O molecular bands, an additional "continuum" source of absorption exists in the window, likely due to CO2 collision-induced bands and extreme far wings of strong CO2 bands. From the variation of the emission with surface elevation, we determined this absorption to be 1.1 ± 0.2 × 10-9 cm-1 amagat-2. From the best fit of the 1.18-micron window in various areas of Venus' southern hemisphere, we derived a H2O mole fraction of 32 ± 7 ppm in the altitude range 0-15 km. This result agrees with previous ground-based and Galileo/NIMS determinations (Taylor et al. 1997, in Venus II, pp. 325-351) but has significantly lower error bars. The derived mole fraction is similar to that inferred at higher altitudes from the 2.3- and 1.74-?m windows, suggesting a constant-with-height water profile from the surface up to 40 km. We also searched for spatial variations of the H2O near-surface abundance using various VIRTIS-M observational sequences and did not detect any latitudinal variations to within 1.5% (i.e. ± 0.5 ppm) in the range 60°S - 20°N.

  7. Solar zenith angle-dependent asymmetries in Venusian bow shock location revealed by Venus Express

    NASA Astrophysics Data System (ADS)

    Chai, Lihui; Wan, Weixing; Fraenz, Markus; Zhang, Tielong; Dubinin, Eduard; Wei, Yong; Li, Yi; Rong, Zhaojin; Zhong, Jun; Han, Xiuhong; Futaana, Yoshifumi

    2015-06-01

    It has been long known that the Venusian bow shock (BS) location is asymmetric from the observations of the long-lived Pioneer Venus Orbiter mission. The Venus Express (VEX) mission crossed BS near perpendicularly not only in the terminator region but also in the near-subsolar and tail regions. Taking the advantage of VEX orbit geometry, we examined a large data set of BS crossings observed during the long-lasting solar minimum between solar cycles 23 and 24 and found that the Venusian BS asymmetries exhibit dependence of solar zenith angle. In the terminator and tail regions, both the magnetic pole-equator and north-south asymmetries are observed in Venusian BS location, which is similar to the Pioneer Venus Orbiter (PVO) observation near terminator. However, in the near-subsolar region, only the magnetic north-south is observed; i.e., the BS shape is indented inward over magnetic south pole and bulged outward over magnetic north pole. The absence of the magnetic pole-equator asymmetry in the near-subsolar region suggests that the magnetic pole-equator asymmetry is mainly caused by the asymmetric wave propagation rather than the ion pickup process. The evident magnetic north-south asymmetry in solar minimum, which is not observed by PVO, suggests that even during the low long-lasting solar minimum, the ion pickup process is very important in Venusian space environment.

  8. A Wind-powered Rover for a Low-Cost Venus Mission

    NASA Technical Reports Server (NTRS)

    Benigno, Gina; Hoza, Kathleen; Motiwala, Samira; Landis, Geoffrey A.; Colozza, Anthony J.

    2013-01-01

    Venus, with a surface temperature of 450 C and an atmospheric pressure 90 times higher than that of the Earth, is a difficult target for exploration. However, high-temperature electronics and power systems now being developed make it possible that future missions may be able to operate in the Venus environment. Powering such a rover within the scope of a Discovery class mission will be difficult, but harnessing Venus' surface winds provides a possible way to keep a powered rover small and light. This project scopes out the feasibility of a wind-powered rover for Venus surface missions. Two rover concepts, a land-sailing rover and a wind-turbine-powered rover, were considered. The turbine-powered rover design is selected as being a low-risk and low-cost strategy. Turbine detailed analysis and design shows that the turbine can meet mission requirements across the desired range of wind speeds by utilizing three constant voltage generators at fixed gear ratios.

  9. Investigating Climate on Venus with Future Missions (Invited)

    NASA Astrophysics Data System (ADS)

    Grinspoon, D. H.

    2013-12-01

    Venus presents unique opportunities to study climate on a nearby, active planet that is both surprisingly like Earth and startlingly different. Venus is remarkably like Earth in terms of bulk properties such as size, mass and density. And yet its modern climate has evolved to a state which is dramatically divergent from that of Earth. Thus Venus presents a fascinating experimental laboratory for studying and modeling climate processes on an Earth-sized world with a strong atmospheric greenhouse and for exploring the role of heliocentric distance and other initial conditions in determining the outcome of climate evolution on an Earth-like planet. Previous spacecraft investigations of Venus, combined with ground based observations, have confirmed the existence of a dynamic, changeable atmosphere with a deep troposphere extending to an altitude of 65 km, a highly variable globally encompassing cloud deck extending from 48 to 70 km altitude, and a complex pattern of global circulation dominated by superrotating winds which circle the globe at a rate up to 60 times faster than the retrograde rotation of the solid planet, with the peak wind velocities at an altitude of 60 km. Other large scale features of the global circulation include Hadley cells in which air rises at low latitudes and travels poleward at high altitudes; and large, complex vortices at both poles where sinking air from the Hadley circulation intersects with the superrotation. Attempts to model this global circulation using modified terrestrial General Circulation Models (GCMs) have been only partially successful. Such tests have the promise of not only increasing our understanding of the Venus atmosphere and its response to solar radiation, but improving our general knowledge of climate and global circulation on Earth-sized terrestrial planets, including Earth itself. They also serve as a 'reality check' on the current generation of terrestrial GCMs and their ability to accurately model climate and circulation on radically altered versions of Earth's climate. In the framework of comparative planetology, climate models and GCMs in particular have taken on a vital role in understanding and predicting the role of anthropogenic forcing in Earth's climate, and separating human from natural influences. The potential role of new spacecraft observations of Venus in improving our ability to accurately model climate on moderately to severely perturbed variations of Earth's current climate is thus extremely valuable. Several efforts to model climate on Venus using terrestrial GCMs have reproduced the gross properties of the Venusian global circulation. These efforts have also revealed that various components of terrestrial GCMs are 'hard coded' with empirically-derived assumptions that are at best only accurate for the current terrestrial climate. Many of these assumptions are hidden within complex 'black boxes' of code that are not always obvious to the modelers using the code. Thus pushing the codes near to, or beyond, the breaking point by applying them toward the problem of Venus helps to improve the veracity and reliability of these models for terrestrial applications. At this point our ability to greatly improve upon these efforts is hampered by the amount and quality of available data on the Venus atmosphere. In order to understand which model, and which assumptions are correct, improved spacecraft observations from several platforms are required.

  10. Venus

    NASA Astrophysics Data System (ADS)

    Fegley, B., Jr.

    2003-12-01

    Venus is Earth's nearest planetary neighbor, and has fascinated mankind since the dawn of history. Venus' clouds reflect most of the sunlight shining on the planet and make it the brightest object in the sky after the Sun and Moon. Venus is visible with the naked eye as an evening star until a few hours after sunset, or as a morning star shortly before sunrise. Many ancient civilizations observed and worshipped Venus, which had a different name in each society, e.g., Ishtar to the Babylonians, Aphrodite to the Greeks, Tai'pei to the Chinese, and Venus to the Romans (Hunt and Moore, 1982). Venus has continued to play an important role in myth, literature, and science throughout history. In the early seventeenth century, Galileo's observations of the phases of Venus showed that the geocentric (Ptolemaic) model of the solar system was wrong and that the heliocentric (Copernican) model was correct. About a century later, Edmund Halley proposed that the distance from the Earth to the Sun (which was then unknown and is defined as one astronomical unit, AU) could be measured by observing transits of Venus across the Sun. These transits occur in pairs separated by eight years at intervals of 105.5 yr and 121.5 yr in an overall cycle of 243 yr, e.g., June 6, 1761, June 3, 1769; December 9, 1874, December 6, 1882, June 8, 2004, June 6, 2012, December 11, 2117, and December 8, 2125. The first attempted measurements of the astronomical unit during the 1761 transit were unsuccessful. However, several observers reported a halo around Venus as it entered and exited the Sun's disk. Thomas Bergman in Uppsala and Mikhail Lomonosov in St. Petersburg, independently speculated that the halo was due to an atmosphere on Venus. Eight years later observations of the 1769 solar transit (including those made by Captain Cook's expedition to Tahiti) gave a value of 1 AU=153 million kilometers, ~2.3% larger than the actual size (149.6 million kilometers) of the astronomical unit (Woolf, 1959; Maor, 2000).

  11. Long-term variations of carbon monoxide and trace species in the Venus troposphere from Venus Express/VIRTIS between 2006-2009

    NASA Astrophysics Data System (ADS)

    Tsang, Constantine; McGouldrick, Kevin

    2015-11-01

    The understanding of spatial and temporal variations in tropospheric abundances of trace gases such as carbon monoxide is key to understanding the deep atmosphere of Venus. These gases are entrained in the global circulation, as well as being key ingredients to creating the sulfuric acid clouds. Long-term temporal variations of these species across Venus’s disc would be provide key insights into the large-scale circulation and cloud forming processes in the troposphere.The Venus Express spacecraft orbited Venus from April 2006 to December 2014. The VIRTIS instrument is a near-infrared imaging spectrometer that covers 0.3 to 5.0 µm. Nightside thermal emissions at 2.32 µm is sensitive to CO at 35 km. We present long term abundances of CO and other trace abundances as observed by VIRTIS from April 2006 through October 2008, when the MIR channel ceased operations. We compare the methods of Tsang et al. (2009) and Barstow et al. (2012) of deriving CO from band ratios. We will also provide long-term variations of cloud particle sizes. This work is done in conjunction with a study of long-term variations of 1.73 µm thermal emission brightnesses, a proxy of cloud optical depth in the lower atmosphere, with the same data (McGouldrick and Tsang 2015). This work is supported by NASA’s Planetary Mission Data Analysis Program, grant number NNX14AP94G.

  12. Assessing the long-term variability of Venus winds at cloud level from VIRTIS-Venus Express

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Peralta, J.; Sánchez-Lavega, A.

    2012-02-01

    The Venus Express (VEX) mission has been in orbit to Venus for more than 4 years now. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument onboard VEX observes Venus in two channels (visible and infrared) obtaining spectra and multi-wavelength images of the planet that can be used to sample the atmosphere at different altitudes. Day-side images in the ultraviolet range (380 nm) are used to study the dynamics of the upper cloud at 66-72 km while night-side images in the near infrared (1.74 ?m) map the opacity of the lower cloud deck at 44-48 km. Here we present a long-term analysis of the global atmospheric dynamics at these levels using a large selection of orbits from the VIRTIS-M dataset covering 860 Earth days that extends our previous work (Sánchez-Lavega, A. et al. [2008]. Geophys. Res. Lett. 35, L13204) and allows studying the variability of the global circulation at the two altitude levels. The atmospheric superrotation is evident with equatorial to mid-latitudes westward velocities of 100 and 60 m s -1 in the upper and lower cloud layers. These zonal velocities are almost constant in latitude from the equator to 50°S. From 50°S to 90°S the zonal winds at both cloud layers decrease steadily to zero at the pole. Individual cloud tracked winds have errors of 3-10 m s -1 with a mean of 5 m s -1 and the standard deviations for a given latitude of our zonal and meridional winds are 9 m s -1. The zonal winds in the upper cloud change with the local time in a way that can be interpreted in terms of a solar tide. The zonal winds in the lower cloud are stable at mid-latitudes to the tropics and present variability at subpolar latitudes apparently linked to the activity of the South polar vortex. While the upper cloud presents a net meridional motion consistent with the upper branch of a Hadley cell with peak velocity v = 10 m s -1 at 50°S, the lower cloud meridional motions are less organized with some cloud features moving with intense northwards and southwards motions up to v = ±15 m s -1 but, on average, with almost null global meridional motions at all latitudes. We also examine the long-term behavior of the winds at these two vertical layers by comparing our extended wind tracked data with results from previous missions.

  13. Venus Exploration opportunities within NASA's Solar System Exploration roadmap

    NASA Technical Reports Server (NTRS)

    Balint, Tibor; Thompson, Thomas; Cutts, James; Robinson, James

    2006-01-01

    Science goals to understand the origin, history and environment of Venus have been driving international space exploration missions for over 40 years. Past missions include the Magellan and Pioneer-Venus missions by the US; the Venera program by the USSR; and the Vega missions through international cooperation. Furthermore, the US National Research Council (NRC), in the 2003 Solar System Exploration (SSE) Decadal Survey, identified Venus as a high priority target, thus demonstrating a continuing interest in Earth's sister planet. In response to the NRC recommendation, the 2005 NASA SSE Roadmap included a number of potential Venus missions arching through all mission classes from small Discovery, to medium New Frontiers and to large Flagship class missions. While missions in all of these classes could be designed as orbiters with remote sensing capabilities, the desire for scientific advancements beyond our current knowledge - including what we expect to learn from the ongoing ESA Venus Express mission - point to in-situ exploration of Venus.

  14. Venus, Mars, and the ices on Mercury and the moon: astrobiological implications and proposed mission designs.

    PubMed

    Schulze-Makuch, Dirk; Dohm, James M; Fairén, Alberto G; Baker, Victor R; Fink, Wolfgang; Strom, Robert G

    2005-12-01

    Venus and Mars likely had liquid water bodies on their surface early in the Solar System history. The surfaces of Venus and Mars are presently not a suitable habitat for life, but reservoirs of liquid water remain in the atmosphere of Venus and the subsurface of Mars, and with it also the possibility of microbial life. Microbial organisms may have adapted to live in these ecological niches by the evolutionary force of directional selection. Missions to our neighboring planets should therefore be planned to explore these potentially life-containing refuges and return samples for analysis. Sample return missions should also include ice samples from Mercury and the Moon, which may contain information about the biogenic material that catalyzed the early evolution of life on Earth (or elsewhere). To obtain such information, science-driven exploration is necessary through varying degrees of mission operation autonomy. A hierarchical mission design is envisioned that includes spaceborne (orbital), atmosphere (airborne), surface (mobile such as rover and stationary such as lander or sensor), and subsurface (e.g., ground-penetrating radar, drilling, etc.) agents working in concert to allow for sufficient mission safety and redundancy, to perform extensive and challenging reconnaissance, and to lead to a thorough search for evidence of life and habitability. PMID:16379531

  15. Preliminary study of laser-induced breakdown spectroscopy (LIBS) for a Venus mission

    SciTech Connect

    Arp, Z. A.; Cremers, D. A.; Wiens, R. C.

    2004-01-01

    Laser-Induced Breakdown Spectroscopy (LIBS) has been proposed as a candidate analysis system for missions to Mars, asteroids, and recently Venus. This technique has several distinct advantages over other techniques which have been used on past missions (X-Ray fluorescence on Viking 1 and 2, 1976; APXS on Pathfiider, 1997; MER, 2004). Two of the more important advantages LIBS has over other techniques for a mission to Venus is rapid elemental analysis of both high and low Z value elements and stand-off analysis at distances of many meters. Rapid elemental analysis and stand-off analysis are very important to missions to Venus due to the harsh environment at the planet surface. From the Venera missions it is known that on the Venusian surface the pressures are approximately 9.1 MPa (90 atm) and the temperature is near 735 K. For these reasons, the Soviet Venera surface probes had operational lifetimes of less than 2 hours. Currently Venus is the target of one of four missions specifically mentioned for consideration for NASA's New Frontier Program with a launch date of 2010 or earlier. In light of this, it is beneficial to evaluate different analysis methods such as LIBS, which offer to greatly increase the scientific return from such a mission. Currently we have begun to evaluate LIBS detection in an environment with pressures and compositions which are similar to those found on Venus. Although the temperature of Venus ({approx} 735 K) has not been taken into account in these experiments, due to the high temperature of the plasma ({approx}8000 K) signifcant perturbations of excitation characteristics sufficient to affect LIBS analytical capability would not be expected. Previous work, however, has shown that the pressure of the surrounding atmosphere can have a strong effect on the detection of elements in soil. These studies have mainly concentrated on pressures at or below earth ambient pressure, but one study has shown successful results at elevated pressures (3.0 MPa). Here we show results from a LIBS study at 9.1 MPa (90 atm) which demonstrates the feasibility of using this technique for elemental analysis at high pressure.

  16. Mitigating Extreme Environments for In-Situ Jupiter and Venus Missions

    NASA Technical Reports Server (NTRS)

    Balint, Tibor S.; Kolawa, Elizabeth A.; Cutts, James A.

    2006-01-01

    In response to the recommendations by the National Research Council (NRC), NASA's Solar System Exploration (SSE) Roadmap identified the in situ exploration of Venus and Jupiter as high priority science objectives. For Jupiter, deep entry probes are recommended, which would descend to approx.250 km - measured from the 1 bar pressure depth. At this level the pressure would correspond to approx.100 bar and the temperature would reach approx.500(deg)C. Similarly, at the surface of Venus the temperature and pressure conditions are approx.460(deg)C and approx.90 bar. Lifetime of the Jupiter probes during descent can be measured in hours, while in{situ operations at and near the surface of Venus are envisioned over weeks or months. In this paper we discuss technologies, which share commonalities in mitigating these extreme conditions over proposed mission lifetimes, specially focusing on pressure and temperature environments.

  17. Experiencing Venus: Clues to the Origin, Evolution, and Chemistry of Terrestrial Planets

    E-print Network

    Atreya, Sushil

    171 Experiencing Venus: Clues to the Origin, Evolution, and Chemistry of Terrestrial Planets via In of knowledge of (1) the origin and evolution of Venus and (2) the photochemical and thermochemical processes orbital observations by ESA's Venus Express and Japan's Venus Climate Orbiter missions. We review the need

  18. Analysis of Venus Express optical extinction due to aerosols in the upper haze of Venus

    NASA Astrophysics Data System (ADS)

    Parkinson, Christopher; Bougher, Stephen; Mahieux, Arnaud; Tellmann, Silvia; Pätzold, Martin; Vandaele, Ann C.; Wilquet, Valérie; Schulte, Rick; Yung, Yuk; Gao, Peter; Bardeen, Charles

    Observations by the SPICAV/SOIR instruments aboard Venus Express (VEx) have revealed that the Upper Haze of Venus is populated by two particle modes, as reported by Wilquet et al. (J. Geophys. Res., 114, E00B42, 2009; Icarus 217, 2012). Gao et al. (In press, Icarus, 2013) posit that the large mode is made up of cloud particles that have diffused upwards from the cloud deck below, while the smaller mode is generated by the in situ nucleation of meteoric dust. They tested this hypothesis by using version 3.0 of the Community Aerosol and Radiation Model for Atmospheres, first developed by Turco et al. (J. Atmos. Sci., 36, 699-717, 1979) and upgraded to version 3.0 by Bardeen et al. (The CARMA 3.0 microphysics package in CESM, Whole Atmosphere Working Group Meeting, 2011). Using the meteoric dust production profile of Kalashnikova et al. (Geophys. Res. Lett., 27, 3293-3296, 2000), the sulfur/sulfate condensation nuclei production profile of Imamura and Hashimoto (J. Atmos. Sci., 58, 3597-3612, 2001), and sulfuric acid vapor production profile of Zhang et al. (Icarus, 217, 714-739, 2012), they numerically simulate a column of the Venus atmosphere from 40 to 100 km above the surface. Their aerosol number density results agree well with Pioneer Venus Orbiter (PVO) data from Knollenberg and Hunten (J. Geophys. Res., 85, 8039-8058, 1980), while their gas distribution results match that of Kolodner and Steffes below 55 km (Icarus, 132, 151-169, 1998). The resulting size distribution of cloud particles shows two distinct modes, qualitatively matching the observations of PVO. They also observe a third mode in their results with a size of a few microns at 48 km altitude, which appears to support the existence of the controversial third mode in the PVO data. This mode disappears if coagulation is not included in the simulation. The Upper Haze size distribution shows two lognormal-like distributions overlapping each other, possibly indicating the presence of the two distinct modes. In this work, we significantly extend the analysis to include new SOIR (PSS, 2014 Submitted) and VeRa VEx temperature profiles (which are quite different from the PVO profiles) and discuss our new results in context of the recent VEx observations (Wilquet et al., Icarus 217, 2012) with an inter comparison with the PVO data. We will also discuss similarities and differences arising from the PVO and VEx epochs where they exist.

  19. Structure and variability of the Venus ionosphere inferred from photoelectron measurements by Venus Express

    NASA Astrophysics Data System (ADS)

    Molaverdikhani, K.; Brain, D. A.; Futaana, Y.

    2012-12-01

    The ionosphere of an unmagnetized planet lies at the boundary between the collisional atmosphere and the passing solar wind. Atmospheric particles escaping from the planet either originate in or pass through the ionosphere. The extent and variability of the ionosphere is of interest for both plasma escape, and the dynamics of the neutral upper atmosphere. Photoelectrons are excellent tracers of ionospheric plasma. Produced via photoionization of atmospheric neutral particles by solar EUV and X-ray radiation, photoelectrons remain tightly bound to magnetic field lines passing through their location of origin. Spacecraft measurements of ionospheric photoelectrons therefore allow us to infer which regions of space around a planet are magnetically connected to the ionosphere. At Venus, the dominant neutral species at high altitudes (i.e. above 300km) are atomic oxygen and carbon dioxide. Using the Electron Spectrometer (ELS) on the Analyser of Space Plasmas and Energetic Atoms (ASPERA-4) instrument package on Venus Express (VEX), previous case studies have reported the presence of ionospheric photoelectrons near Venus produced by solar HeII 30.4 nm photons. We aim to accomplish a comprehensive statistical survey of ionospheric photoelectrons, revealing the variability and extent of the ionosphere for different external conditions. We have developed and tested an automatic algorithm to detect the presence of photoelectrons in ASPERA-4 ELS measurements. The algorithm (filter) identifies ionospheric photoelectron distributions as a localized peak between 20 to 30 eV in electron energy spectrum. We have applied the filter to determine the distribution of photoelectron percentage of occurrence (photoelectron likelihood). The observations reveal increasing dayside ionospheric altitudes as solar zenith angle increases, followed by a sudden decrease at the terminator. Ionospheric photoelectrons are evident outside of the eclipse boundary on the night side tail of the planet to high altitudes. Increases in ionospheric altitude are correlated with increases in solar ionizing flux (i.e. EUV and soft x-ray). We present the characteristics of the measured photoelectron energy distributions, such as integrated flux, peak flux, width, and the measured energy of the peak, and we show how they vary temporally and spatially at Venus.

  20. The relationship between mesoscale circulation and cloud morphology at the upper cloud level of Venus from VMC/Venus Express

    NASA Astrophysics Data System (ADS)

    Patsaeva, M. V.; Khatuntsev, I. V.; Patsaev, D. V.; Titov, D. V.; Ignatiev, N. I.; Markiewicz, W. J.; Rodin, A. V.

    2015-08-01

    The Venus Monitoring Camera (VMC) acquired a set of ultraviolet (UV) images during the Venus Express mission unprecedented in its duration from May 2006 to September 2013. Here we present the results of digital tracking of the cloud features in the upper cloud layer at latitudes 25-75°S using images from 257 orbits with the best spatial coverage. The method relies on analysis of correlations between pairs of UV images separated in time. The bulk of data processed allows us to clarify the reasons why the mid-latitude jet is not always present in latitudinal wind profiles. Comparing VMC images with wind velocity fields we found a relationship between cloud morphology at middle latitudes and the circulation. The vector field in middle latitudes depends on the presence of a contrast global streak in the cloud morphology tilted with respect to latitude circles. The angle of the flow deflection (the angle between the wind velocity and latitudinal circles) and the difference of the zonal velocity on the opposite sides of the streak are in direct relationship to the angle between the streak and latitude circles. During such orbits the jet bulge does not appear in the latitudinal profile of the zonal wind component. Otherwise a zonal flow with small changes of the meridional velocity dominates in middle latitudes and manifests itself as a jet bulge. The relationship between the cloud cover morphology and circulation peculiarities can be attributed to the motion of global cloud features, like the Y-feature. We prepared plots of zonal and meridional velocities averaged with respect to the entire observation period. The average zonal velocity has a diurnal maximum at 15:00 local solar time and at 40°S. The meridional velocity reaches its maximum between 13:00 and 16:00 and at 50°S. The velocities obtained by the digital method are in good agreement with results of the visual method in the middle latitudes published earlier by Khatuntsev et al. (2013).

  1. Atomic oxygen distributions in the Venus thermosphere: Comparisons between Venus Express observations and global model simulations

    NASA Astrophysics Data System (ADS)

    Brecht, A. S.; Bougher, S. W.; Gérard, J.-C.; Soret, L.

    2012-02-01

    Nightglow emissions provide insight into the global thermospheric circulation, specifically in the transition region (˜70-120 km). The O 2 IR nightglow statistical map created from Venus Express (VEx) Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) observations has been used to deduce a three-dimensional atomic oxygen density map. In this study, the National Center of Atmospheric Research (NCAR) Venus Thermospheric General Circulation Model (VTGCM) is utilized to provide a self-consistent global view of the atomic oxygen density distribution. More specifically, the VTGCM reproduces a 2D nightside atomic oxygen density map and vertical profiles across the nightside, which are compared to the VEx atomic oxygen density map. Both the simulated map and vertical profiles are in close agreement with VEx observations within a ˜30° contour of the anti-solar point. The quality of agreement decreases past ˜30°. This discrepancy implies the employment of Rayleigh friction within the VTGCM may be an over-simplification for representing wave drag effects on the local time variation of global winds. Nevertheless, the simulated atomic oxygen vertical profiles are comparable with the VEx profiles above 90 km, which is consistent with similar O 2 ( 1?) IR nightglow intensities. The VTGCM simulations demonstrate the importance of low altitude trace species as a loss for atomic oxygen below 95 km. The agreement between simulations and observations provides confidence in the validity of the simulated mean global thermospheric circulation pattern in the lower thermosphere.

  2. Venus cloud morphology: monitoring by the VMC/ Venus Express camera continued

    NASA Astrophysics Data System (ADS)

    Titov, Dmitrij V.; Markiewicz, Wojciech J.; Ignatiev, Nikolay I.

    2013-04-01

    Venus Monitoring Camera (VMC) onboard the ESA Venus Express spacecraft continues investigations of the cloud morphology in ultraviolet, visible, and near-IR spectral bands with spatial resolution from 50 km at apocentre to a few hundred of meters at pericentre. The imaging shows strong spatial and latitudinal variations of the cloud pattern and significant temporal changes on all scales. The camera discovered new cloud features like bright "lace clouds" and cloud columns at the low latitudes, dark polar oval and narrow circular and spiral "grooves" in the polar regions, different types of waves at the high latitudes. The VMC observations revealed detailed structure of the sub-solar region and the afternoon convective wake, the bow-shape features and convective cells, the mid-latitude transition region and the "polar cap". Besides the cloud morphology the VMC observations have important implications for the problems of the unknown UV absorber, microphysical processes, dynamics and radiative energy balance at the cloud tops. We will present an overview of the recent VMC observations and compare them to the earlier results.

  3. Integration of Radioisotope Heat Source with Stirling Engine and Cooler for Venus Internal-Structure Mission

    SciTech Connect

    Schock, Alfred

    1993-10-01

    The primary mission goal is to perform long-term seismic measurements on Venus, to study its largely unknown internal structure. The principal problem is that most payload components cannot long survive Venus's harsh environment, 90 bars at 500 degrees C. To meet the mission life goal, such components must be protected by a refrigerated payload bay. JPL Investigators have proposed a mission concept employing a lander with a spherical payload bay cooled to 25 degrees C by a Stirling cooler powered by a radioisotope-heated Sitrling engine. To support JPL's mission study, NASA/Lewis and MTI have proposed a conceptual design for a hydraulically coupled Stirling engine and cooler, and Fairchild Space - with support of the Department of Energy - has proposed a design and integration scheme for a suitable radioisotope heat source. The key integration problem is to devise a simple, light-weight, and reliable scheme for forcing the radioisotope decay heat to flow through the Stirling engine during operation on Venus, but to reject that heat to the external environment when the Stirling engine and cooler are not operating (e.g., during the cruise phase, when the landers are surrounded by heat shields needed for protection during subsequent entry into the Venusian atmosphere.) A design and integration scheme for achieving these goals, together with results of detailed thermal analyses, are described in this paper. There are 7 copies in the file.

  4. A study of an orbital radar mapping mission to Venus. Volume 2: Configuration comparisons and systems evaluation

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Configuration comparisons and systems evaluation for the orbital radar mapping mission of the planet Venus are discussed. Designs are recommended which best satisfy the science objectives of the Venus radar mapping concept. Attention is given to the interaction and integration of those specific mission-systems recommendations with one another, and the final proposed designs are presented. The feasibility, cost, and scheduling of these configurations are evaluated against assumptions of reasonable state-of-the-art growth and space funding expectations.

  5. Europe Scores New Planetary Success: Venus Express Enters Orbit around the Hothouse Planet

    NASA Astrophysics Data System (ADS)

    2006-04-01

    During the next four weeks, the Venus Express probe will perform a series of manoeuvres to reach the scheduled operational orbit for its scientific mission. It will move from its current highly elongated 9-day orbit to a 24-hour polar orbit, culminating at 66,000 km. From this vantage point, the orbiter will conduct an in-depth observation of the structure, chemistry and dynamics of the atmosphere of Venus for at least two Venusian days (486 Earth days). Enigmatic atmosphere From previous missions to Venus as well as observations directly from Earth, we already know that our neighbouring planet is shrouded in a thick atmosphere where extremes of temperature and pressure conditions are common. This atmosphere creates a greenhouse effect of tremendous proportions as it spins around the planet in four days in an unexplained “super-rotation” phenomenon. The mission of Venus Express will be to carry out a detailed characterisation of this atmosphere, using state-of-the-art sensors in order to answer the questions and solve the mysteries left behind by the first wave of explorers. It will also be the first Venus orbiter to conduct optical observations of the surface through “visibility windows” discovered in the infrared spectrum.V The commissioning of the onboard scientific instruments will begin shortly and the first raw data are expected within days. The overall science payload is planned to be fully operational within two months. Europe explores the Solar System With this latest success, ESA is adding another celestial body to its range of solar system studies. ESA also operates Mars Express around Mars, SMART-1 around the Moon and is NASA’s partner on the Cassini orbiter around Saturn. In addition, ESA is also operating the Rosetta probe en route to comet 67P/Churyumov-Gerasimenko. It should reach its target and become the first spacecraft ever to enter orbit around a comet nucleus by 2014. Meanwhile, ESA also plans to complete the survey of our celestial neighbours with the launch of the BepiColombo mission to Mercury in 2013. “With the arrival of Venus Express, ESA is the only space agency to have science operations under way around four planets: Venus, the Moon, Mars and Saturn” underlines Professor David Southwood, the Director of ESA’s science programmes. “We are really proud to deliver such a capability to the international science community.” “To better understand our own planet, we need to explore other worlds in particular those with an atmosphere,” said Jean-Jacques Dordain, ESA Director General. “We’ve been on Titan and we already are around Mars. By observing Venus and its complex atmospheric system, we will be able to better understand the mechanisms that steers the evolution of a large planetary atmosphere and the change of climates. In the end, it will help us to get better models of what is actually going on in our own atmosphere, for the benefit of all Earth citizens.” State-of-the-art science package Venus Express was developed for ESA by a European industrial team led by EADS Astrium incorporating 25 main contractors from 14 European countries. Its design is derived from that of its highly successful predecessor, Mars Express, and its payload accommodates seven instruments including upgraded versions of three instruments developed for Mars Express and two for Rosetta. The PFS spectrometer will determine the temperature and composition profile of the atmosphere at very high resolution. It will also monitor the surface temperature and search for hot spots from possible volcanic activity. The UV/infrared SpicaV/SOIR spectrometer and the VeRa radioscience experiment will probe the atmosphere by observing the occultation of distant starts or the fading of radio signals on the planetary limb. SpicaV/SOIR will be particularly looking for traces of water molecules, molecular oxygen and sulphur compounds, which are suspected to exist in the atmosphere of Venus. The Virtis spectrometer will map the different layers of the atmosphere and provide imagery of the cloud systems at multipl

  6. The dayside ionospheres of Mars and Venus: Comparing a one-dimensional photochemical model with MaRS (Mars Express)

    E-print Network

    Withers, Paul

    The dayside ionospheres of Mars and Venus: Comparing a one-dimensional photochemical model with MaRS (Mars Express) and VeRa (Venus Express) observations Kerstin Peter a, , Martin Pätzold a , Gregorio Keywords: Mars Venus Ionosphere a b s t r a c t The electron density distributions of the lower ionospheres

  7. Small-scale temperature fluctuations seen by the VeRa Radio Science Experiment on Venus Express

    E-print Network

    Spiga, Aymeric

    Small-scale temperature fluctuations seen by the VeRa Radio Science Experiment on Venus Express S August 2012 Accepted 9 August 2012 Available online 30 August 2012 Keywords: Venus Atmospheres, Dynamics Occultations Radio observations a b s t r a c t The Venus Express Radio Science Experiment VeRa retrieves

  8. Reassessing the possibility of life on venus: proposal for an astrobiology mission.

    PubMed

    Schulze-Makuch, Dirk; Irwin, Louis N

    2002-01-01

    With their similar size, chemical composition, and distance from the Sun, Venus and Earth may have shared a similar early history. Though surface conditions on Venus are now too extreme for life as we know it, it likely had abundant water and favorable conditions for life when the Sun was fainter early in the Solar System. Given the persistence of life under stabilizing selection in static environments, it is possible that life could exist in restricted environmental niches, where it may have retreated after conditions on the surface became untenable. High-pressure subsurface habitats with water in the supercritical liquid state could be a potential refugium, as could be the zone of dense cloud cover where thermoacidophilic life might have retreated. Technology based on the Stardust Mission to collect comet particles could readily be adapted for a pass through the appropriate cloud layer for sample collection and return to Earth. PMID:12469368

  9. Analysis of Trajectory Parameters for Probe and Round-Trip Missions to Venus

    NASA Technical Reports Server (NTRS)

    Dugan, James F., Jr.; Simsic, Carl R.

    1960-01-01

    For one-way transfers between Earth and Venus, charts are obtained that show velocity, time, and angle parameters as functions of the eccentricity and semilatus rectum of the Sun-focused vehicle conic. From these curves, others are obtained that are useful in planning one-way and round-trip missions to Venus. The analysis is characterized by circular coplanar planetary orbits, successive two-body approximations, impulsive velocity changes, and circular parking orbits at 1.1 planet radii. For round trips the mission time considered ranges from 65 to 788 days, while wait time spent in the parking orbit at Venus ranges from 0 to 467 days. Individual velocity increments, one-way travel times, and departure dates are presented for round trips requiring the minimum total velocity increment. For both single-pass and orbiting Venusian probes, the time span available for launch becomes appreciable with only a small increase in velocity-increment capability above the minimum requirement. Velocity-increment increases are much more effective in reducing travel time for single-pass probes than they are for orbiting probes. Round trips composed of a direct route along an ellipse tangent to Earth's orbit and an aphelion route result in the minimum total velocity increment for wait times less than 100 days and mission times ranging from 145 to 612 days. Minimum-total-velocity-increment trips may be taken along perihelion-perihelion routes for wait times ranging from 300 to 467 days. These wait times occur during missions lasting from 640 to 759 days.

  10. The variable upper atmosphere of Venus, as determined by data from drag and torque measurements by Venus Express

    NASA Astrophysics Data System (ADS)

    Svedhem, Håkan; Müller-Wodarg, Ingo; Rosenblatt, Pascal

    2013-04-01

    Until recently the only information on the structure of the polar upper atmosphere of Venus available has been based on the reference atmosphere models such as the VTS3 or VIRA models. These models extrapolate the values from low latitudes to high latitudes by using equivalent solar zenith angles. New measurements by Venus Express show that such extrapolations not always give correct results and that there is a permanent overestimate of the density at high latitudes. These new results have been reached by using two different but related techniques, both using an atmospheric drag effect on the spacecraft. By reducing the pericentre altitude the total mass density in the altitude range 150-200km can be measured in situ by monitoring the orbital decay caused by the drag on the spacecraft by the atmosphere via direct tracking of the Doppler signal on the telecommunication link. Such measurements have been performed with Venus Express several times during the last years as part of the Venus Express Atmospheric Drag Experiment (VExADE). The results indicate a large variability within only a few days and have led to questions if these variations are real or within the uncertainty of the measurements. A completely different and independent measurement is given by monitoring the torque asserted by the atmosphere on the spacecraft. This is done by monitoring the momentum accumulated in the reaction wheels during the pericenter pass and at the same time considering all other perturbing forces. This requires the spacecraft to fly in an asymmetric attitude with respect to the center of gravity, center of drag and the velocity vector. This technique has proven very sensitive, in particular if the geometric asymmetry is large, and offers an additional method of measuring atmospheric densities in-situ that previously had not been explored with the Venus Express spacecraft. Similar measurements have been done in the past by Magellan at Venus and by Cassini at Titan. Between 2009 and 2012 several campaigns, with altitudes going as low as 165 km, were held. The highest density measured was 7.7 10-12kg/m3 which is significantly less than earlier models predict. The results largely confirm the density measurements by the VExADE drag measurements and add to the confidence in the results from these measurements. By using these drag and torque results and assuming a hydrostatic diffusive equilibrium atmosphere a new model has been constructed. The model is fitted to the Venus Express remote sensing measurements in the upper mesosphere (VeRa radio occultation data) and lower thermosphere (SpicaV/SOIR data) to give a continuous transition across the different regions.

  11. RAVEN - High-resolution Mapping of Venus within a Discovery Mission Budget

    NASA Astrophysics Data System (ADS)

    Sharpton, V. L.; Herrick, R. R.; Rogers, F.; Waterman, S.

    2009-12-01

    It has been more than 15 years since the Magellan mission mapped Venus with S-band synthetic aperture radar (SAR) images at ~100-m resolution. Advances in radar technology are such that current Earth-orbiting SAR instruments are capable of providing images at meter-scale resolution. RAVEN (RAdar at VENus) is a mission concept that utilizes the instrument developed for the RADARSAT Constellation Mission (RCM) to map Venus in an economical, highly capable, and reliable way. RCM relies on a C-band SAR that can be tuned to generate images at a wide variety of resolutions and swath widths, ranging from ScanSAR mode (broad swaths at 30-m resolution) to strip-map mode (resolutions as fine as 3 m), as well as a spotlight mode that can image patches at 1-m resolution. In particular, the high-resolution modes allow the landing sites of previous missions to be pinpointed and characterized. Repeat-pass interferometric SAR (InSAR) and stereo radargrammetry provide options for constraining topography to better than 100-m horizontal and 10-m vertical resolution. InSAR also provides the potential for detecting surface deformation at centimeter precision. Performing InSAR requires precise knowledge and control of the orbital geometry, and for this reason a 600-km circular polar orbit is favored. This configuration causes the equatorial nadir point to move ~9 km per orbit. Considering both ascending and descending passes, the spacecraft will pass over every point on the planet in half a Venus day (~4 Earth months). The ability to transmit data back to Earth via the Deep Space Network is the primary limiting factor on the volume of data that can be collected. Our current estimates indicate that within an imaging cycle of one Venus day we can image 20-30 percent of the planet at 20-30-m resolution and several percent at 3-5 m resolution. These figures compare favorably to the coverage provided by recent imaging systems orbiting Mars. Our strategy calls for the first cycle of coverage to be devoted to imaging large geographic areas (e.g., Thetis Regio) at 20-30-m resolution with interleaved observation of pre-selected targets at high resolution. The second cycle will include additional imaging, but the focus will be repeat-pass coverage to obtain topography for a significant fraction of the first-cycle targets. A focus of the third cycle will be InSAR-based deformation studies of selected areas. All components of the spacecraft are expected to remain operational well beyond the nominal mission time, so global mapping at 10 m or better resolution during an extended mission is conceivable. RAVEN will allow us to determine both the broad framework of the planet’s geologic history (e.g, uniformitarian versus catastrophic evolution) and the nature of current geologic activity. It will substantially advance our understanding of Venus and reveal details, issues, and further questions that will benefit future site-specific missions such as probes and landers. Current RAVEN science team members are Buck Sharpton (PI), Rudi Gens, Rebecca Ghent, Martha Gilmore, Robert Grimm, Robert Herrick, Catherine Johnson, Patrick McGovern, Franz Meyer, Peter Mouginis-Mark, Jeff Plaut, David Sandwell, Mark Simons, and Sean Solomon.

  12. Interplanetary Coronal Mass Ejections observed by MESSENGER and Venus Express

    E-print Network

    Good, S W

    2015-01-01

    Interplanetary coronal mass ejections (ICMEs) observed by the MESSENGER (MES) and Venus Express (VEX) spacecraft have been catalogued and analysed. The ICMEs were identified by a relatively smooth rotation of the magnetic field direction consistent with a flux rope structure, coinciding with a relatively enhanced magnetic field strength. A total of 35 ICMEs were found in the surveyed MES data (primarily from March 2007 to April 2012), and 84 ICMEs in the surveyed VEX data (from May 2006 to December 2013). The ICME flux rope configurations have been determined. Ropes with northward leading edges were about four times more common than ropes with southward leading edges, in agreement with a previously established solar cycle dependence. Ropes with low inclinations to the solar equatorial plane were about four times more common than ropes with high inclinations, possibly an observational effect. Left and right-handed ropes were observed in almost equal numbers. In addition, data from MES, VEX, STEREO-A, STEREO-B ...

  13. Exploring Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2008-01-01

    With a temperature higher than the inside of your oven and atmospheric pressure equal to that a kilometer under the ocean, the surface of Venus is one of the most hostile environments in the solar system, and Venus exploration presents a challenge to technology. This lecture presents mission trade-offs and discusses a proposed mission concept for rover and aircraft based exploration of the surface and atmosphere of Venus. Several approaches to the technology, electronics, mechanical parts, and power systems, are discussed.

  14. PC-402 Pioneer Venus orbiter spacecraft mission operational characteristics document

    NASA Technical Reports Server (NTRS)

    Barker, F. C.; Butterworth, L. W.; Daniel, R. E.; Drean, R. J.; Filetti, K. A.; Fisher, J. N.; Nowak, L. A.; Porzucki, J.; Salvatore, J. O.; Tadler, G. A.

    1978-01-01

    The operational characteristics of the Orbiter spacecraft and its subsystems are described. In extensive detail. Description of the nominal phases, system interfaces, and the capabilities and limitations of system level performance are included along with functional and operational descriptions at the subsystem and unit level the subtleties of nominal operation as well as detailed capabilities and limitations beyond nominal performance are discussed. A command and telemetry logic flow diagram for each subsystem is included. Each diagram encountered along each command signal path into, and each telemetry signal path out of the subsystem. Normal operating modes that correspond to the performance of specific functions at the time of specific events in the mission are also discussed. Principal backup means of performing the normal Orbiter operating modes are included.

  15. Tropospheric carbon monoxide concentrations and variability on Venus from Venus Express/VIRTIS-M observations

    NASA Astrophysics Data System (ADS)

    Tsang, Constantine C. C.; Irwin, Patrick G. J.; Wilson, Colin F.; Taylor, Fredric W.; Lee, Chris; de Kok, Remco; Drossart, Pierre; Piccioni, Giuseppe; Bezard, Bruno; Calcutt, Simon

    2008-10-01

    We present nightside observations of tropospheric carbon monoxide in the southern hemisphere near the 35 km height level, the first from Venus Express/Visible and Infrared Thermal Imaging Spectrometer (VIRTIS)-M-IR. VIRTIS-M data from 2.18 to 2.50 ?m, with a spectral resolution of 10 nm, were used in the analysis. Spectra were binned, with widths ranging from 5 to 30 spatial pixels, to increase the signal-to-noise ratio, while at the same time reducing the total number of retrievals required for complete spatial coverage. We calculate the mean abundance for carbon monoxide at the equator to be 23 +/- 2 ppm. The CO concentration increases toward the poles, peaking at a latitude of approximately 60°S, with a mean value of 32 +/- 2 ppm. This 40% equator-to-pole increase is consistent with the values found by Collard et al. (1993) from Galileo/NIMS observations. Observations suggest an overturning in this CO gradient past 60°S, declining to abundances seen in the midlatitudes. Zonal variability in this peak value has also been measured, varying on the order of 10% (~3 ppm) at different longitudes on a latitude circle. The zonal variability of the CO abundance has possible implications for the lifetime of CO and its dynamics in the troposphere. This work has definitively established a distribution of tropospheric CO, which is consistent with a Hadley cell circulation, and placed limits on the latitudinal extent of the cell.

  16. A search for optical evidence for lightning on Venus with VIRTIS on Venus Express

    NASA Astrophysics Data System (ADS)

    Abildgaard, Sofie; Cardesin, Alejandro; Garcia Múnoz, Antonio; Piccioni, Giuseppe

    2015-04-01

    Lightning is known to occur on the atmospheres of Earth, Jupiter, Saturn, Uranus and Neptune, but although the occurrence of lightning in the Venusian atmosphere has been published several times in the past years, always on the basis of detected electromagnetic pulses, the subject is still controversial. It is generally agreed that an optical observation of the phenomenon would settle the issue. In this work we analyse the data collection of hyper-spectral images produced by the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) on Venus Express, that has been observing the Venusian atmosphere continuously since 2006. A dedicated search algorithm for transient events was developed and a detailed analysis of the archive was performed in all wavelengths. The first preliminary analysis have been performed and we have proven that transient events can easily be identified in the data. Work is ongoing for optimizing search parameters and performing a statistical analysis. In this contribution, we will present a summary of the data analysis process and some of the preliminary conclusion in the lightning detection/nondetection.

  17. Six years of Venus winds at the upper cloud level from UV, visible and near infrared observations from VIRTIS on Venus Express

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Peralta, J.; Garate-Lopez, I.; Bandos, T. V.; Sánchez-Lavega, A.

    2015-08-01

    The Venus Express mission has provided a long-term monitoring of Venus atmosphere including the morphology and motions of its upper clouds. Several works have focused on the dynamics of the upper cloud visible on the day-side in ultraviolet images sensitive to the 65-70 km altitude and in the lower cloud level (50 km height) observable in the night-side of the planet in the 1.74 ?m spectral window. Here we use VIRTIS-M spectral images in nearby wavelengths to study the upper cloud layer in three channels: ultraviolet (360-400 nm), visible (570-680 nm) and near infrared (900-955 nm) extending in time the previous analysis of VIRTIS-M data. The ultraviolet images show relatively well contrasted cloud features at the cloud top. Cloud features in the visible and near infrared images lie a few kilometers below the upper cloud top, have very low contrast and are distinct to the features observed in the ultraviolet. Wind measurements were obtained on 118 orbits covering the Southern hemisphere over a six-year period and using a semi-automatic cloud correlation algorithm. Results for the upper cloud from VIRTIS-M ultraviolet data confirm previous analysis based on images obtained by the Venus Monitoring Camera (Khatuntsev et al. (2013)). At the cloud top the mean zonal and meridional winds vary with local time accelerating towards the local afternoon. The upper branch of the Hadley cell circulation reaches maximum velocities at 45° latitude and local times of 14-16 h. The mean zonal winds in the ultraviolet cloud layer accelerated in the course of the 2006-2012 period at least 15 m s-1. The near infrared and visible images show a more constant circulation without significant time variability or longitudinal variations. The meridional circulation is absent or slightly reversed in near infrared and visible images indicating that, either the Hadley-cell circulation in Venus atmosphere is shallow, or the returning branch of the meridional circulation extends to levels below the cloud level sensed in near infrared images. At subpolar to polar latitudes the three wavelength ranges show similar features and motions which is a signature of small vertical wind shear and may be affected by vertical convergence of both layers. At the clod top level observed in UV images there are signatures of a long-term acceleration of the zonal winds at afternoon hours when comparing zonal winds from the first years of Venus Express observations (2006-2008) to later dates (2009-2012) with a mean acceleration of zonal winds of 17±6 m s-1 between both time periods.

  18. Advanced Stirling Duplex Materials Assessment for Potential Venus Mission Heater Head Application

    NASA Technical Reports Server (NTRS)

    Ritzert, Frank; Nathal, Michael V.; Salem, Jonathan; Jacobson, Nathan; Nesbitt, James

    2011-01-01

    This report will address materials selection for components in a proposed Venus lander system. The lander would use active refrigeration to allow Space Science instrumentation to survive the extreme environment that exists on the surface of Venus. The refrigeration system would be powered by a Stirling engine-based system and is termed the Advanced Stirling Duplex (ASD) concept. Stirling engine power conversion in its simplest definition converts heat from radioactive decay into electricity. Detailed design decisions will require iterations between component geometries, materials selection, system output, and tolerable risk. This study reviews potential component requirements against known materials performance. A lower risk, evolutionary advance in heater head materials could be offered by nickel-base superalloy single crystals, with expected capability of approximately 1100C. However, the high temperature requirements of the Venus mission may force the selection of ceramics or refractory metals, which are more developmental in nature and may not have a well-developed database or a mature supporting technology base such as fabrication and joining methods.

  19. Venus cloud bobber mission: A long term survey of the Venusian surface

    NASA Technical Reports Server (NTRS)

    Wai, James; Derengowski, Cheryl; Lautzenhiser, Russ; Emerson, Matt; Choi, Yongho

    1994-01-01

    We have examined the Venus Balloon concept in order to further develop the ideas and concepts behind it, and to creatively apply them to the design of the major Venus Balloon components. This report presents our models of the vertical path taken by the Venus Balloon and the entry into Venusian atmosphere. It also details our designs of the balloon, gondola, heat exchanger, power generator, and entry module. A vehicle is designed for a ballistic entry into the Venusian atmosphere, and an atmospheric model is created. The model is then used to set conditions. The shape and material of the vehicle are optimized, and the dimensions of the vehicle are then determined. Equipment is chosen and detailed that will be needed to collect and transmit information and control the mission. A gondola is designed that will enable this sensitive electronic equipment to survive in an atmosphere of very high temperature and pressure. This shape and the material of the shell are optimized, and the size is minimized. Insulation and supporting structures are designed to protect the payload equipment and to minimize mass. A method of cooling the gondola at upper altitudes was established. Power needs of the gondola equipment are determined. Power generation options are discussed and two separate thermoelectric generation models are outlined.

  20. A recommended entry reconstruction process for the Pioneer Venus multi-probe mission

    NASA Technical Reports Server (NTRS)

    Findlay, J. T.; Kelly, G. M.

    1978-01-01

    A method for determining the entry trajectories for the Pioneer Venus multi-probe mission is presented that utilizes earth based Doppler and onboard accelerometry as observables to provide updates for the spacecraft state and atmospheric parameters. The evolution of this method, based on error analyses and actual simulation results, is discussed. A derivative of the Viking radio science orbit determination software is recommended for the reconstruction. Telemetry data pre-processing requirements were defined. A cubic spline derivative routine is recommended to extract accelerations from the accumulated velocity decrements.

  1. Dayside temperatures in the Venus upper atmosphere from Venus Express/VIRTIS nadir measurements at 4.3 ?m

    NASA Astrophysics Data System (ADS)

    Peralta, J.; López-Valverde, M. A.; Gilli, G.; Piccialli, A.

    2016-01-01

    In this work, we analysed nadir observations of atmospheric infrared emissions carried out by VIRTIS, a high-resolution spectrometer on board the European spacecraft Venus Express. We focused on the ro-vibrational band of CO2 at 4.3 ?m on the dayside, whose fluorescence originates in the Venus upper mesosphere and above. This is the first time that a systematic sounding of these non-local thermodynamic equilibrium (NLTE) emissions has been carried out in Venus using this geometry. As many as 143,218 spectra have been analysed on the dayside during the period 14/05/2006 to 14/09/2009. We designed an inversion method to obtain the atmospheric temperature from these non-thermal observations, including a NLTE line-by-line forward model and a pre-computed set of spectra for a set of thermal structures and illumination conditions. Our measurements sound a broad region of the upper mesosphere and lower thermosphere of Venus ranging from 10-2-10-5 mb (which in the Venus International Reference Atmosphere, VIRA, is approximately 100-150 km during the daytime) and show a maximum around 195 ± 10 K in the subsolar region, decreasing with latitude and local time towards the terminator. This is in qualitative agreement with predictions by a Venus Thermospheric General Circulation Model (VTGCM) after a proper averaging of altitudes for meaningful comparisons, although our temperatures are colder than the model by about 25 K throughout. We estimate a thermal gradient of about 35 K between the subsolar and antisolar points when comparing our data with nightside temperatures measured at similar altitudes by SPICAV, another instrument on Venus Express (VEx). Our data show a stable temperature structure through five years of measurements, but we also found episodes of strong heating/cooling to occur in the subsolar region of less than two days. The table with numerical data and averaged temperatures displayed in Fig. 7A provided as a CSV data file is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/585/A53

  2. Characterizing the V1 layer in the Venus ionosphere using VeRa observations from Venus Express

    NASA Astrophysics Data System (ADS)

    Girazian, Z.; Withers, P.; Fallows, K.; Tarrh, A.; Paetzold, M.; Tellmann, S.; Haesler, B.

    2013-12-01

    The Venus Radio Science Experiment (VeRa) on the Venus Express spacecraft sounds the Venus atmosphere during Earth occultations to obtain vertical profiles of electron density in the ionosphere. The resultant profiles reveal the vertical structure of the Venus ionosphere from the topside down to below the lower layers (< 115 km). On the dayside, the dominant plasma layer is the V2 layer at ~142 km, which is produced primarily by photoionization of CO2. Embedded on the bottomside of the V2 layer is the less prominent, and much less studied, V1 layer at ~127 km. The V1 layer is also produced by photoionization of CO2, but secondary ionization due to energetic photoelectrons is much more important. Here we investigate properties of the V1 layer using VeRa profiles from 2006 to 2012 during which the Sun went from the deep solar minimum of Solar Cycle 23 to the rising solar activity levels of Solar Cycle 24. We investigate how the peak electron density and peak altitude of the V1 layer depend on solar zenith angle. We also characterize the shapes of the V1 layer and show how they are related to the solar activity level. Solar spectra from the Solar EUV Experiment (SEE) on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) spacecraft are used to characterize the shapes of the V1 layer with solar activity.

  3. Retrieval of the cyclostrophic wind in the Venus mesosphere from the VIRTIS/Venus Express temperature sounding.

    NASA Astrophysics Data System (ADS)

    Piccialli, Arianna; Titov, Dmitri; Grassi, Davide; Khatuntsev, Igor; Drossart, Pierre; Piccioni, Giuseppe; Migliorini, Alessandra

    Venus mesosphere is characterized by an extremely complex dynamics: a retrograde super rotation flow near the cloud top completes a full rotation of the planets in only four earth days and in the upper thermosphere a solar - antisolar circulation reaches speeds of 100 m/s. Earlier studies have shown that the strong zonal winds at cloud top are the result of local balance of pressure gradient and centripetal force which is called cyclostrophic balance. The thermal wind equation that describes this balance relates the vertical wind gradient to the latitudinal temperature gradient on isobaric levels. The temperature structure of Venus mesosphere has been observed with a good spatial and temporal coverage in the last two years from VIRTIS (Visual and Infrared Thermal Imaging Spectrometer) on board the Venus Express spacecraft. Here we present preliminary retrievals of the cyclostrophic wind derived from VIRTIS temperature sounding. The main features of the wind are 1) the midlatitude jet with a maximum speed of 80 - 90 ± 10 m/s which occurs around 50° S latitude at 70 km altitude; 2) the fast decrease of the wind speed from 60° S toward the pole; 3) the decrease of the wind speed with increasing height above the jet. The dependence of zonal wind on local time has been analysed, our preliminary results show that parameters of the mid-latitude jet only weekly depend on local solar time. Comparison with cloud - tracked wind derived from the Venus Monitoring Camera (VMC) show a general good agreement.

  4. Quantification of middle and lower cloud variability and mesoscale dynamics from Venus Express/VIRTIS observations at 1.74 ?m

    NASA Astrophysics Data System (ADS)

    McGouldrick, Kevin; Momary, Thomas W.; Baines, Kevin H.; Grinspoon, David H.

    2012-02-01

    We present an analysis of VIRTIS-M-IR observations of 1.74 ?m emission from the nightside of Venus. The 1.74 ?m window in the near infrared spectrum of Venus is an ideal proxy for investigating the evolution of middle and lower cloud deck opacity of Venus because it exhibits good signal to noise due to its brightness, good contrast between bright and dark regions, and few additional sources of extinction beside the clouds themselves. We have analyzed the data from the first 407 orbits (equivalent to 407 Earth days) of the Venus Express mission to determine the magnitude of variability in the 1.74 ?m radiance. We have also performed an analysis of the evolution of individual features over a span of roughly 5-6 h on two successive orbits of Venus Express. We find that the overall 1.74 ?m brightness of Venus has been increasing through the first 407 days of the mission, indicating a gradual diminishing of the cloud coverage and/or thickness, and that the lower latitudes exhibited more variability and more brightening than higher latitudes. We find that individual features evolve with a time scale of about 30 h, consistent with our previous analysis. Analysis of the evolution and motion of the clouds can be used to estimate the mesoscale dynamics within the clouds of Venus. We find that advection alone cannot explain the observed evolution of the features. The measured vorticity and divergence in the vicinity of the features are consistent with evolution under the influence of significant vertical motions likely driven by a radiative dynamical feedback. We measure a zonal wind speed of around 65 m/s, and a meridional wind speed around 2.5 m/s by tracking the motion of the central region of the features. But we also find that the measured wind speeds depend strongly on the points chosen for the wind speed analysis.

  5. Preliminary observations by Venus Express/VIRTIS of the distribution of carbon monoxide in the lower atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Tsang, C. C. C.; Taylor, F. W.; Irwin, P. G. J.; Drossart, P.; Piccioni, G.; Wilson, C. F.; Virtis/Venus Express

    The minor constituent carbon monoxide (CO) is an important tracer of the dynamics and chemistry of the Venusian atmosphere. Galileo/NIMS observations in 1990 found a poleward increase of CO in the height range around 40 km in the northern hemisphere (Collard et. al., PSS, 1993), which was confirmed by subsequent high-resolution ground-based spectral observations (Marq et al., Icarus, 2005). Taylor (Adv. Space Res., 1995) presented an interpretation of the NIMS observations of CO in terms of an atmospheric circulation containing hemispherical Hadley cells that extend from the surface up to the mesosphere. Here we present some new observations by the VIRTIS instrument on Venus Express of the variability of CO below the clouds on Venus. They show that the equator-to-pole gradient is also present in the southern hemisphere, and that it peaks near 60 degrees. A search for longitudinal variations of CO will be shown.

  6. Update of the Venus density and temperature profiles at high altitude measured by SOIR on board Venus Express

    NASA Astrophysics Data System (ADS)

    Mahieux, A.; Vandaele, A. C.; Bougher, S. W.; Drummond, R.; Robert, S.; Wilquet, V.; Chamberlain, S.; Piccialli, A.; Montmessin, F.; Tellmann, S.; Pätzold, M.; Häusler, B.; Bertaux, J. L.

    2015-08-01

    The SOIR instrument on board Venus Express regularly sounds the Venus atmosphere using the solar occultation technique. The density and temperature profiles are inferred from SOIR spectra recorded in the infrared. The method has been described in a previous publication (Mahieux et al., 2012. J. Geophys. Res. 117. doi:10.1029/2012JE004058.). This paper is devoted to the update of the VAST (Venus Atmosphere from SOIR measurements at the Terminator) compilation that was initiated in the above cited work, which gives the mean CO2 number density and temperature profiles for different latitude bins. The method has been improved and has been applied to more data. The new compilation which is given on the same latitudinal grid now distinguishes between the two sides of the terminator. The compilation also confirms the main thermal layering characteristics that were identified in the earlier version: the succession of a warm layer (230±30 K, 1-? standard deviation) at a pressure level of 3.2×10-7 mbar (~140 km), a very cold layer (125±32 K) at 2.5×10-5 mbar (~123 km), a warm layer (204±17 K) at 0.01 mbar (~102 km) and finally a colder layer at 0.4 mbar (171±34 K, ~87 km). The layering of all the temperature profiles is explained by radiative rather than dynamical processes. The temporal temperature variation is larger than the mean latitudinal temperature variation. VAST is compared with temperature profiles obtained from other Venus Express instruments, VeRa and SPICAV-UV, and ground based measurements.

  7. Morphology of the cloud tops as observed by the Venus Express Monitoring Camera

    NASA Astrophysics Data System (ADS)

    Titov, Dmitrij V.; Markiewicz, Wojciech J.; Ignatiev, Nikolay I.; Song, Li; Limaye, Sanjay S.; Sanchez-Lavega, Agustin; Hesemann, Jonas; Almeida, Miguel; Roatsch, Thomas; Matz, Klaus-Dieter; Scholten, Frank; Crisp, David; Esposito, Larry W.; Hviid, Stubbe F.; Jaumann, Ralf; Keller, Horst U.; Moissl, Richard

    2012-02-01

    Since the discovery of ultraviolet markings on Venus, their observations have been a powerful tool to study the morphology, motions and dynamical state at the cloud top level. Here we present the results of investigation of the cloud top morphology performed by the Venus Monitoring Camera (VMC) during more than 3 years of the Venus Express mission. The camera acquires images in four narrow-band filters centered at 365, 513, 965 and 1010 nm with spatial resolution from 50 km at apocentre to a few hundred of meters at pericentre. The VMC experiment provides a significant improvement in the Venus imaging as compared to the capabilities of the earlier missions. The camera discovered new cloud features like bright "lace clouds" and cloud columns at the low latitudes, dark polar oval and narrow circular and spiral "grooves" in the polar regions, different types of waves at the high latitudes. The VMC observations revealed detailed structure of the sub-solar region and the afternoon convective wake, the bow-shape features and convective cells, the mid-latitude transition region and the "polar cap". The polar orbit of the satellite enables for the first time nadir viewing of the Southern polar regions and an opportunity to zoom in on the planet. The experiment returned numerous images of the Venus limb and documented global and local brightening events. VMC provided almost continuous monitoring of the planet with high temporal resolution that allowed one to follow changes in the cloud morphology at various scales. We present the in-flight performance of the instrument and focus in particular on the data from the ultraviolet channel, centered at the characteristic wavelength of the unknown UV absorber that yields the highest contrasts on the cloud top. Low latitudes are dominated by relatively dark clouds that have mottled and fragmented appearance clearly indicating convective activity in the sub-solar region. At ˜50° latitude this pattern gives way to streaky clouds suggesting that horizontal, almost laminar, flow prevails here. Poleward from about 60°S the planet is covered by almost featureless bright polar hood sometimes crossed by dark narrow (˜300 km) spiral or circular structures. This global cloud pattern can change on time scales of a few days resulting in global and local "brightening events" when the bright haze can extend far into low latitudes and/or increase its brightness by 30%. Close-up snapshots reveal plenty of morphological details like convective cells, cloud streaks, cumulus-like columns, wave trains. Different kinds of small scale waves are frequently observed at the cloud top. The wave activity is mainly observed in the 65-80° latitude band and is in particular concentrated in the region of Ishtar Terra that suggests their possible orographic origin. The VMC observations have important implications for the problems of the unknown UV absorber, microphysical processes, dynamics and radiative energy balance at the cloud tops. They are only briefly discussed in the paper, but each of them will be the subject of a dedicated study.

  8. The electrical performance of Ag Zn batteries for the Venus multi-probe mission

    NASA Technical Reports Server (NTRS)

    Palandati, C.

    1975-01-01

    An evaluation of 5 Ah and 21 Ah Silver-Zinc batteries was made to determine their suitability to meet the energy storage requirements of the bus vehicle, 3 small probes and large probe for the Venus multi-probe mission. The evaluation included a 4 Ah battery for the small probe, a 21 Ah battery for the large probe, one battery of each size for the bus vehicle power, a periodic cycling test on each size battery and a wet stand test of charged and discharged cells of both cell designs. The study on the probe batteries and bus vehicle batteries included both electrical and thermal simulation for the entire mission. The effects on silver migration and zinc penetration of the cellophane separators caused by the various test parameters were determined by visual and X-ray fluorescence analysis. The 5 Ah batteries supported the power requirements for the bus vehicle and small probe. The 21 Ah large probe battery supplied the required mission power. Both probe batteries delivered in excess of 132 percent of rated capacity at the completion of the mission simulation.

  9. Tracking of Mars Express and Venus Express spacecraft with VLBI radio telescopes

    NASA Astrophysics Data System (ADS)

    Molera Calvés, G.; Pogrebenko, S. V.; Wagner, J.; Cimò, G.; Gurvits, L.; Duev, D.

    2010-12-01

    The ESA Mars Express and Venus Express spacecraft (S/C) have been observed for the last two years with the European VLBI radio telescopes of Metsähovi (FI), Wettzell (GE), Yebes (SP), Medicina, Matera, Noto (IT), Puschino (RU) and Onsala (SW). The campaign is in the framework of the assessment study and preparation of the European VLBI Network to the upcoming ESA and other deep space missions. It also offers new opportunities for applications of radio astronomy techniques to planetary science, geophysics and geodesy. Observations are carried out either in single- or multi-dish modes when S/C is locked to the ESA’s ESTRACK ground stations (Cebreros or New Nortia) observing the two way link. Data are recorded locally at the stations using standard VLBI equipment and transferred to the Metsähovi for processing. Further on, the data are transferred from Metsähovi to Joint Institute for VLBI in Europe for further post-analysis. High dynamic range of the S/C signal detections allowed us to determine the apparent topocentric frequency of the S/C carrier line and accompanying ranging tones down to milli-Hz spectral accuracy and to extract the phase of the S/C signal carrier line. With multi-station observations, the respective phases can be calibrated on the per-baseline basis using VLBI phase referencing technique and observations of background quasars close to S/C in their celestial position using far-field VLBI delay model for quasars and near-field model for S/C. The post-analysis of the S/C tracking data enables us to study several parameters of the S/C signals. Of these, the phase fluctuations of the signal can be used for characterization of the interplanetary plasma density fluctuations along the signal propagation line at different spatial and temporal scales and different solar elongations. These fluctuations are well represented by a near-Kolmogorov spectrum. Multi-station observations can distinguish the contributions of propagation effects in the plasma along the up- and down-link paths as seen from different VLBI stations through different Fresnel channels. We also demonstrated high accuracy S/C Doppler tracking with 3 EVN stations (Metsähovi, Wettzell and Yebes) during the MEX-Phobos flyby, which occurred on 2010 march 03. These multi-station observing sessions could help to better determine the Phobos gravity field and together with phase referencing provide additional geometrical constrains on the orbiter/Phobos trajectories. VEX S/C signal detection with four VLBI antennae (23/08/2010).

  10. Mission Sizing and Trade Studies for Low Ballistic Coefficient Entry Systems to Venus

    NASA Technical Reports Server (NTRS)

    Dutta, Soumyo; Smith, Brandon; Prabhu, Dinesh; Venkatapathy, Ethiraj

    2012-01-01

    The U.S and the U.S.S.R. have sent seventeen successful atmospheric entry missions to Venus. Past missions to Venus have utilized rigid aeroshell systems for entry. This rigid aeroshell paradigm sets performance limitations since the size of the entry vehicle is constrained by the fairing diameter of the launch vehicle. This has limited ballistic coefficients (beta) to well above 100 kg/m2 for the entry vehicles. In order to maximize the science payload and minimize the Thermal Protection System (TPS) mass, these missions have entered at very steep entry flight path angles (gamma). Due to Venus thick atmosphere and the steep-gamma, high- conditions, these entry vehicles have been exposed to very high heat flux, very high pressures and extreme decelerations (upwards of 100 g's). Deployable aeroshells avoid the launch vehicle fairing diameter constraint by expanding to a larger diameter after the launch. Due to the potentially larger wetted area, deployable aeroshells achieve lower ballistic coefficients (well below 100 kg/m2), and if they are flown at shallower flight path angles, the entry vehicle can access trajectories with far lower decelerations (50-60 g's), peak heat fluxes (400 W/cm2) and peak pressures. The structural and TPS mass of the shallow-gamma, low-beta deployables are lower than their steep-gamma, high-beta rigid aeroshell counterparts at larger diameters, contributing to lower areal densities and potentially higher payload mass fractions. For example, at large diameters, deployables may attain aeroshell areal densities of 10 kg/m2 as opposed to 50 kg/m2 for rigid aeroshells. However, the low-beta, shallow-gamma paradigm also raises issues, such as the possibility of skip-out during entry. The shallow-gamma could also increase the landing footprint of the vehicle. Furthermore, the deployable entry systems may be flexible, so there could be fluid-structure interaction, especially in the high altitude, low-density regimes. The need for precision in guidance, navigation and control during entry also has to be better understood. This paper investigates some of the challenges facing the design of a shallow-gamma, low-beta entry system.

  11. Future dedicated Venus-SGG flight mission: Accuracy assessment and performance analysis

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Hsu, Houtse; Zhong, Min; Yun, Meijuan

    2016-01-01

    This study concentrates principally on the systematic requirements analysis for the future dedicated Venus-SGG (spacecraft gravity gradiometry) flight mission in China in respect of the matching measurement accuracies of the spacecraft-based scientific instruments and the orbital parameters of the spacecraft. Firstly, we created and proved the single and combined analytical error models of the cumulative Venusian geoid height influenced by the gravity gradient error of the spacecraft-borne atom-interferometer gravity gradiometer (AIGG) and the orbital position error and orbital velocity error tracked by the deep space network (DSN) on the Earth station. Secondly, the ultra-high-precision spacecraft-borne AIGG is propitious to making a significant contribution to globally mapping the Venusian gravitational field and modeling the geoid with unprecedented accuracy and spatial resolution through weighing the advantages and disadvantages among the electrostatically suspended gravity gradiometer, the superconducting gravity gradiometer and the AIGG. Finally, the future dedicated Venus-SGG spacecraft had better adopt the optimal matching accuracy indices consisting of 3 × 10-13/s2 in gravity gradient, 10 m in orbital position and 8 × 10-4 m/s in orbital velocity and the preferred orbital parameters comprising an orbital altitude of 300 ± 50 km, an observation time of 60 months and a sampling interval of 1 s.

  12. Atmospheric Entry Studies for Venus Missions: 45 Sphere-Cone Rigid Aeroshells and Ballistic Entries

    NASA Technical Reports Server (NTRS)

    Prabhu, Dinesh K.; Spilker, Thomas R.; Allen, Gary A., Jr.; Hwang, Helen H.; Cappuccio, Gelsomina; Moses, Robert W.

    2013-01-01

    The present study considers direct ballistic entries into the atmosphere of Venus using a 45deg sphere-cone rigid aeroshell, a legacy shape that has been used successfully in the past in the Pioneer Venus Multiprobe Mission. For a number of entry mass and heatshield diameter combinations (i.e., various ballistic coefficients) and entry velocities, the trajectory space in terms of entry flight path angles between skip out and -30deg is explored with a 3DoF trajectory code, TRAJ. From these trajectories, the viable entry flight path angle space is determined through the use of mechanical and thermal performance limits on the thermal protection material and science payload; the thermal protection material of choice is entry-grade carbon phenolic, for which a material thermal response model is available. For mechanical performance, a 200 g limit is placed on the peak deceleration load experienced by the science instruments, and 10 bar is assumed as the pressure limit for entry-grade carbon-phenolic material. For thermal performance, inflection points in the total heat load distribution are used as cut off criteria. Analysis of the results shows the existence of a range of critical ballistic coefficients beyond which the steepest possible entries are determined by the pressure limit of the material rather than the deceleration load limit.

  13. Horizontal Distribution of CO, OCS and H2O Below the Clouds of Venus From Venus Express/VIRTIS Observations

    NASA Astrophysics Data System (ADS)

    Bezard, Bruno; Marcq, E.; Tsang, C. C.; Taylor, F. W.; Drossart, P.; Piccioni, G.; Encrenaz, T.; Vex/VIRTIS Team

    2006-09-01

    Nightside spectroscopy in the 2.3-?m window allows us to probe the composition of the lower atmosphere of Venus in the altitude range 28-42 km. Besides CO2, signatures from CO, OCS, H2O, HDO, HF and SO2 can be detected (e.g. Bézard et al. 1990, Nature 345, 508-511; Taylor et al. 1997, in Venus II, pp. 325-351, Univ. Arizona Press, Tucson). We report here on the first observations of this window on Venus' night side obtained with the VIRTIS instrument aboard Venus Express. It was observed at a resolving power (R) of about 2000 with the H-channel, a high-resolution spectrometer covering the range 1.9-5 ?m, and at R 250 with the infrared M-channel, an imaging spectrometer for the range 1-5 ?m. We present maps of CO in the southern hemisphere obtained with the M-channel and latitudinal variations of CO, OCS and H2O derived from a set of VIRTIS-H scans. CO clearly increases from equator to 60°S with a slight decrease polewards. Longitudinal structure is also present. The inferred gradient is consistent with the ground-based observations of Marcq et al. (2005, Icarus 179, 375-386; 2006, Planet. Space Sci., in press) below 40° latitude and mirrors the enhancement seen at high northern latitudes in the Galileo data (Collard et al. 1993, Planet. Space Sci. 41, 487-494). CO appears as a tracer of the atmospheric dynamics, giving evidence for upwelling in the equatorial region and subsidence at high latitudes.

  14. Future Exploration of Venus: Opportunities and Challenges

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay; Svedhem, Håkan; Nakamura, Masato; Zasova, Ludila; Kiran Kumar, A. S.; Bullock, Mark; Wilson, Colin

    2012-07-01

    The successful fly-by of Venus by Mariner 2 began a half century of planetary exploration. During the last three decades Venus has been explored by orbiters, probes and balloons and even opportunistic fly-bys of VeGA, Galileo, Cassini and MESSENGER spacecraft, and currently ESA's Venus Express orbiter is returning data from its 24-hour highly eccentric polar orbit and JAXA's Akatsuki spacecraft awaits orbit insertion around Venus in 2015 or 2016. Recently the Planetary Science Decadal Survey (2013-2022) conducted by the US National Academies recommended a flagship mission to Venus. The current and future budget scenarios for NASA indicate that such a mission can be realized through international partnerships and collaborations. It is useful therefore to examine the scientific observations of Venus that have not yet been obtained and explore the current technological capabilities that have been developed and can be useful for Venus missions. These include long lived balloons, more efficient electric power generation, Unmanned Aerial Vehicles (UAV), surface seismometry stations and others. NASA's Venus Exploration Analysis Group (VEXAG) provides a forum for the international Venus community to consider international collaborations and scientists are invited to participate in the discussions.

  15. Investigation of winds in Venus mesosphere by digital method using UV images from VMC aboard Venus Express.

    NASA Astrophysics Data System (ADS)

    Patsaeva, Marina; Khatuntsev, Igor; Ignatiev, Nikolai

    2013-04-01

    Investigation of winds at the top cloud layer is important for understanding the global circulation of the Venus atmosphere. The Venus Monitoring Camera (VMC) aboard Venus Express has acquired a huge number of UV (365 nm) images. UV images of top cloud layer are customary to obtain the wind velocity due to their high contrast. Visual estimation of wind velocities is a labor intensive procedure. Authors have developed a digital method to estimate velocities of shifts of cloud details. The method is based on analysis of correlations between two UV images acquired at different moments. The method takes into account the change of a correlation function due to latitudinal peculiarities of cloud morphology and eliminates image regions which are far from the sub-spacecraft point. The digital method provides with good vector coverage of the Venus day side (9-16 local time) from the equator to high latitudes. The best agreement between the digital and visual methods is observed at low latitudes (below 35S). The discrepancy at higher latitudes is related to complicated cloud morphology, namely domination of streaks, which increases errors in the zonal wind speed. The method is productive for long-scale circulation at the top cloud layer. Sizes of regions for correlation were chosen empirically as a trade-off of sensitivity against noise immunity and varies from 10x7.5 ° to 20x10 ° depending on grid step. 580 orbits covering ten Venus years have been processed by using the digital method. The database of shift vectors counts about 400000 records. The mean wind speed at low latitudes is about 100 m/s. Wind vector fields were obtained for every orbit. The zonal wind speed in the equatorial region exhibits short-period (about 4.8 days) and long-period variations (long-term trend). Vector field averaged by all orbits show deviations of the main stream up to 5 degrees poleward in the early afternoon (12.5-14.5h) at 45-55S. The mean absolute value of the wind speed increases from 59.38 m/s at 10-12h to 76.46 m/s at 12.5-14.5h at the same latitude interval.

  16. A dynamic upper atmosphere of Venus as revealed by VIRTIS on Venus Express.

    PubMed

    Drossart, P; Piccioni, G; Gérard, J C; Lopez-Valverde, M A; Sanchez-Lavega, A; Zasova, L; Hueso, R; Taylor, F W; Bézard, B; Adriani, A; Angrilli, F; Arnold, G; Baines, K H; Bellucci, G; Benkhoff, J; Bibring, J P; Blanco, A; Blecka, M I; Carlson, R W; Coradini, A; Di Lellis, A; Encrenaz, T; Erard, S; Fonti, S; Formisano, V; Fouchet, T; Garcia, R; Haus, R; Helbert, J; Ignatiev, N I; Irwin, P; Langevin, Y; Lebonnois, S; Luz, D; Marinangeli, L; Orofino, V; Rodin, A V; Roos-Serote, M C; Saggin, B; Stam, D M; Titov, D; Visconti, G; Zambelli, M; Tsang, C; Ammannito, Eleonora; Barbis, Alessandra; Berlin, Rainer; Bettanini, Carlo; Boccaccini, Angelo; Bonnello, Guillaume; Bouyé, Marc; Capaccioni, Fabrizio; Cardesin, Alejandro; Carraro, Francesco; Cherubini, Giovanni; Cosi, Massimo; Dami, Michele; De Nino, Maurizio; Del Vento, Davide; Di Giampietro, Marco; Donati, Alessandro; Dupuis, Olivier; Espinasse, Sylvie; Fabbri, Anna; Fave, Agnès; Veltroni, Iacopo Ficai; Filacchione, Gianrico; Garceran, Katia; Ghomchi, Yamina; Giustizi, Maurizio; Gondet, Brigitte; Hello, Yann; Henry, Florence; Hofer, Stefan; Huntzinger, Gerard; Kachlicki, Juergen; Knoll, René; Kouach, Driss; Mazzoni, Alessandro; Melchiorri, Riccardo; Mondello, Giuseppe; Monti, Francesco; Neumann, Christian; Nuccilli, Fabrizio; Parisot, Jérôme; Pasqui, Claudio; Perferi, Stefano; Peter, Gisbert; Piacentino, Alain; Pompei, Carlo; Réess, Jean-Michel; Rivet, Jean-Pierre; Romano, Antonio; Russ, Natalie; Santoni, Massimo; Scarpelli, Adelmo; Sémery, Alain; Soufflot, Alain; Stefanovitch, Douchane; Suetta, Enrico; Tarchi, Fabio; Tonetti, Nazzareno; Tosi, Federico; Ulmer, Bernd

    2007-11-29

    The upper atmosphere of a planet is a transition region in which energy is transferred between the deeper atmosphere and outer space. Molecular emissions from the upper atmosphere (90-120 km altitude) of Venus can be used to investigate the energetics and to trace the circulation of this hitherto little-studied region. Previous spacecraft and ground-based observations of infrared emission from CO2, O2 and NO have established that photochemical and dynamic activity controls the structure of the upper atmosphere of Venus. These data, however, have left unresolved the precise altitude of the emission owing to a lack of data and of an adequate observing geometry. Here we report measurements of day-side CO2 non-local thermodynamic equilibrium emission at 4.3 microm, extending from 90 to 120 km altitude, and of night-side O2 emission extending from 95 to 100 km. The CO2 emission peak occurs at approximately 115 km and varies with solar zenith angle over a range of approximately 10 km. This confirms previous modelling, and permits the beginning of a systematic study of the variability of the emission. The O2 peak emission happens at 96 km +/- 1 km, which is consistent with three-body recombination of oxygen atoms transported from the day side by a global thermospheric sub-solar to anti-solar circulation, as previously predicted. PMID:18046396

  17. Pluto Express: Mission to Pluto

    NASA Technical Reports Server (NTRS)

    Giuliano, J. A.

    1996-01-01

    Pluto is the smallest, outermost and last-discovered planet in the Solar System and the only one that has never been visited by a spacecraft from Earth. Pluto and its relatively large satellite Charon are the destinations of a proposed spacecraft mission for the next decade, being developed for NASA by scientists and engineers at NASA's Jet Propulsion Laboratory.

  18. A study of an orbital radar mapping mission to Venus. Volume 3: Parametric studies and subsystem comparisons

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Parametric studies and subsystem comparisons for the orbital radar mapping mission to planet Venus are presented. Launch vehicle requirements and primary orbiter propulsion system requirements are evaluated. The systems parametric analysis indicated that orbit size and orientation interrelated with almost all of the principal spacecraft systems and influenced significantly the definition of orbit insertion propulsion requirements, weight in orbit capability, radar system design, and mapping strategy.

  19. Radial Evolution of a Magnetic Cloud: MESSENGER, STEREO, and Venus Express Observations

    NASA Astrophysics Data System (ADS)

    Good, S. W.; Forsyth, R. J.; Raines, J. M.; Gershman, D. J.; Slavin, J. A.; Zurbuchen, T. H.

    2015-07-01

    The Solar Orbiter and Solar Probe Plus missions will provide observations of magnetic clouds closer to the Sun than ever before, and it will be good preparation for these missions to make full use of the most recent in situ data sets from the inner heliosphere—namely, those provided by MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and Venus Express—for magnetic cloud studies. We present observations of the same magnetic cloud made by MESSENGER at Mercury and later by Solar TErrestrial RElations Observatory-B (STEREO-B), while the spacecraft were radially aligned in 2011 November. Few such radial observations of magnetic clouds have been previously reported. Estimates of the solar wind speed at MESSENGER are also presented, calculated through the application of a previously established technique. The cloud's flux rope has been analyzed using force-free fitting; the rope diameter increased from 0.18 to 0.41 AU (corresponding to an {r}{{H}}0.94 dependence on heliocentric distance, rH), and the axial magnetic field strength dropped from 46.0 to 8.7 nT (an {r}{{H}}-1.84 dependence) between the spacecraft, clear indications of an expanding structure. The axial magnetic flux was ˜0.50 nT AU2 at both spacecraft, suggesting that the rope underwent no significant erosion through magnetic reconnection between MESSENGER and STEREO-B. Further, we estimate the change in the cloud's angular width by assuming helicity conservation. It has also been found that the rope axis rotated by 30° between the spacecraft to lie close to the solar equatorial plane at STEREO-B. Such a rotation, if it is a common feature of coronal mass ejection propagation, would have important implications for space weather forecasting.

  20. United StatesNASA Support of the Venus Express Mission

    E-print Network

    Rathbun, Julie A.

    Program Support Sub-Task Manager Jet Propulsion Laboratory Concurred by: James A. Cutts Planetary Science Program Support Task Manager Jet Propulsion Laboratory Acknowledgments Key inputs to this document were Administration. JPL D-94392 June 25, 2015 Jet Propulsion Laboratory California Institute of Technology Pasadena

  1. Sulfur Dioxide variability in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Vandaele, Ann C.; Esposito, Larry W.; Lefevre, Franck; Mills, Franklin; Limaye, Sanjay; Mahieux, Arnaud; Belyaev, Denis; Encrenaz, Therese; Marcq, Emmanuel; Korablev, Oleg; Parkinson, Christopher; Wilson, Colin; Wilquet, Valérie; Chamberlain, Sarah; Jessup, Kandis Lea; Stolzenbach, Aurelien

    The recent observations of SO _{2} by SOIR and SPICAV-UV on board Venus Express and ground-based observations of SO _{2} and SO have provoked much reaction in the scientific community. SO _{2} is strongly related to the formation of the clouds and haze on Venus, which are composed of sulfuric acid combined to water complexes. Presence and variations of SO _{2} could be the proof of a possible volcanism on Venus. The most intriguing are discrepancies among different observations, and the suspected long-term variations of the SO _{2} abundance observed on the scales of several years, in particular during Pioneer Venus Orbiter and Venus Express missions. Similar trends are also observed in the super-rotation period and circulation patterns, which suggest that these aspects may be more strongly coupled than expected. An ISSI international team has been built in view of considering different aspects of sulfur chemistry on Venus. This includes comparison and validation of observations, from past missions, from Venus Express, from the Earth, and from Hubble Space Telescope, modeling of photochemistry and of other processes in which the sulfur family is involved. We will consider not only SO _{2}, but also SO and other constituents involved in its cycle. Reference density and vmr fields will be constructed from the detailed analysis and comparison of data. These will be included into the next generation of the VIRA references atmosphere.

  2. Analysis of Solar Cell Efficiency for Venus Atmosphere and Surface Missions

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Haag, Emily

    2013-01-01

    A simplified model of solar power in the Venus environment is developed, in which the solar intensity, solar spectrum, and temperature as a function of altitude is applied to a model of photovoltaic performance, incorporating the temperature and intensity dependence of the open-circuit voltage and the temperature dependence of the bandgap and spectral response of the cell. We use this model to estimate the performance of solar cells for both the surface of Venus and for atmospheric probes at altitudes from the surface up to 60 km. The model shows that photovoltaic cells will produce power even at the surface of Venus.

  3. Distribution of sulphuric acid aerosols in the clouds and upper haze of Venus using Venus Express VAST and VeRa temperature profiles

    NASA Astrophysics Data System (ADS)

    Parkinson, Christopher D.; Gao, Peter; Schulte, Rick; Bougher, Stephen W.; Yung, Yuk L.; Bardeen, Charles G.; Wilquet, Valérie; Vandaele, Ann Carine; Mahieux, Arnaud; Tellmann, Silvia; Pätzold, Martin

    2015-08-01

    Observations from Pioneer Venus and from SPICAV/SOIR aboard Venus Express (VEx) have shown the upper haze (UH) of Venus to be highly spatially and temporally variable, and populated by multiple particle size modes. Previous models of this system (e.g., Gao et al., 2014. Icarus 231, 83-98), using a typical temperature profile representative of the atmosphere (viz., equatorial VIRA profile), did not investigate the effect of temperature on the UH particle distributions. We show that the inclusion of latitude-dependent temperature profiles for both the morning and evening terminators of Venus helps to explain how the atmospheric aerosol distributions vary spatially. In this work we use temperature profiles obtained by two instruments onboard VEx, VeRa and SPICAV/SOIR, to represent the latitudinal temperature dependence. We find that there are no significant differences between results for the morning and evening terminators at any latitude and that the cloud base moves downwards as the latitude increases due to decreasing temperatures. The UH is not affected much by varying the temperature profiles; however, the haze does show some periodic differences, and is slightly thicker at the poles than at the equator. We also find that the sulphuric acid "rain" seen in previous models may be restricted to the equatorial regions of Venus, such that the particle size distribution is relatively stable at higher latitudes and at the poles.

  4. MESSENGER and Venus Express Observations of the Near-tail of Venus: Magnetic Flux Transport, Current Sheet Structure, and Flux Rope Formation

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Boardsen, S. A.; Sarantos, M.; Acuna, M. H.; Anderson, B. J.; Barabash, S.; Benna, M.; Fraenz, M.; Gloeckler, G.; Gold, R. E.; Ho, G. C.; Korth, H.; Krimigis, S. M.; McNutt, R. L., Jr.; Raines, J. M.; Solomon, S. C.; Zhang, T.-L.; Zurbuchen, T. H.

    2008-01-01

    At 23:08 UT on 5 June 2007 the MESSENGER spacecraft reached its closest approach altitude (338 km) during its second flyby of Venus en route to its 2011 orbit insertion at Mercury. Whereas no measurements were collected during MESSENGER'S first Venus flyby in October 2006, the Magnetometer (MAG) and the Energetic Particle and Plasma Spectrometer (EPPS) operated successfully throughout this second encounter. Venus provides the solar system's best example to date of a solar wind - ionosphere planetary interaction. We present MESSENGER observations of the near-tail of Venus with emphasis on determining the time scales for magnetic flux transport, the structure of the cross-tail current sheet at very low altitudes (approx. 300 to 1000 km), and the nature and origin of a magnetic flux rope observed in the current sheet. The availability of the simultaneous Venus Express upstream measurements provides a unique opportunity to examine the influence of solar wind plasma and interplanetary magnetic field conditions on this planet's solar wind interaction at solar minimum.

  5. Geographic distribution of zonal wind and UV albedo at cloud top level from VMC camera on Venus Express: Influence of Venus topography through stationary gravity waves vertical propagation

    NASA Astrophysics Data System (ADS)

    Bertaux, J.-L.; Khatunstsev, I. V.; Hauchecorne, A.; Markiewicz, W.; Marcq, E.; Lebonnois, S.; Patsaeva, M. V.; Turin, A. V.

    2015-10-01

    Based on the analysis of UV images (at 365 nm) of Venus cloud top collected with VMC camera on board Venus Express[4,5], it is found that the zonal wind speed south of the equator (from 5°S to 15°s) shows a conspicuous variation with geographic longitude of Venus, correlated with underlying relief of Aphrodite Terra. We interpret this pattern as the result of stationary gravity waves produced at ground level by the up lift of air when the horizontal wind encounters a mountain slope. The cloud albedo map at 365 nm varies also in longitude and latitude, perhaps the result of increased vertical mixing associated to wave breaking, and decreased abundance of the UV absorber which makes the contrast in images.

  6. Time-series analysis of temperature profiles from VIRTIS Venus Express data

    NASA Astrophysics Data System (ADS)

    Grassi, D.; Migliorini, A.; Politi, R.; Montabone, L.; Piccioni, G.; Drossart, P.

    2012-04-01

    Nighttime infrared observations of the VIRTIS instrument on board Venus Express have already demonstrated their potential in the study of air temperature fields of the Venusian mesosphere. The entire available dataset acquired by the VIRTIS-M IR channel was processed at moderate spatial resolution (i.e. averaging pixels in 8x8 boxes) to derive an unprecedented dataset of air temperature profiles in the pressure range 100-0.1 mbar, covering mostly the latitudes south of 45S. We presented in Grassi et al. (2010, doi:10.1029/2009JE003553) an analysis of the mean properties of temperature profiles, once binned in the latitude/local time/pressure space. Here we discuss the preliminary findings of time-series analysis of data from individual bins. Despite the sparsity of most series, Lomb-Scargle periodogram can be effectively applied in the regions south of 70S, where better coverage is made possible by specific properties of Venus Express orbit. Here the algorithm is able to extract a clear signature related to a period of about 115-120 Earth days, i.e. one Venus solar day, particularly strong at the level around 10 mbar. Further analysis of average temperature fields in the latitude - longitude space demonstrated, for different local times during night, that air temperatures east of Lada Terra (most specifically in a region centered around 130°E and about 60° wide) are about 10K warmer than in other longitudes at 75S.

  7. Densities inferred from ESA's Venus Express aerobraking campaign at 130 km altitude

    NASA Astrophysics Data System (ADS)

    Bruinsma, Sean; Marty, Jean-Charles; Svedhem, Håkan; Williams, Adam; Mueller-Wodarg, Ingo

    2015-04-01

    In June-July 2014, ESA performed a planned aerobraking campaign with Venus Express to measure neutral densities above 130 km in Venus' atmosphere by means of the engineering accelerometers. To that purpose, the orbit perigee was lowered to approximately 130 km in order to enhance the atmospheric drag effect to the highest tolerable levels for the spacecraft; the accelerometer resolution and precision were not sufficient at higher altitudes. This campaign was requested as part of the Venus Express Atmospheric Drag Experiment (VExADE). A total of 18 orbits (i.e. days) were processed using the attitude quaternions to correctly orient the spacecraft bus and solar arrays in inertial space, which is necessary to accurately compute the exposed surface in the ram direction. The accelerometer data provide good measurements approximately from 130-140 km altitude; the length of the profiles is about 85 seconds, and they are on the early morning side (LST=4.5) at high northern latitude (70°N-82°N). The densities are a factor 2-3 larger than Hedin's VTS-3 thermosphere model, which is consistent with earlier results obtained via classical precise orbit determination at higher altitudes. Wavelike structures with amplitudes of 20% and more are detected, with wavelengths of about 100-500 km. We cannot entirely rule out that these waves are caused by the spacecraft or due to some unknown instrumental effect, but we estimate this probability to be very low.

  8. A suggested trajectory for a Venus-sun, earth-sun Lagrange points mission, Vela

    NASA Technical Reports Server (NTRS)

    Bender, D. F.

    1979-01-01

    The possibility is suggested of investigating the existence of small, as-yet undiscovered, asteroids orbiting in the solar system near the earth-sun or Venus-sun stable Lagrange points by means of a spacecraft which traverses these regions. The type of trajectory suggested lies in the ecliptic plane and has a period of 5/6 years and a perihelion at the Venus orbital distance. The regions in which stable orbits associated with the earth and with Venus may lie are estimated to be a thin and tadpole-shaped area extending from 35 deg to 100 deg from the planet. Crossings of the regions by the trajectory are described, and the requirements for detecting the presence of 1 km sized asteroids are presented and shown to be attainable.

  9. Constraints on Magmatic Diversity on Venus from Terrestrial Analog Crystallization Experiments with Data Implications for Future Missions

    NASA Astrophysics Data System (ADS)

    Filiberto, J.

    2013-12-01

    Igneous diversity,common on the Earth, is possible on Venus based on: the Venera and Vega analyses of rocks on the surface of Venus [1,2], orbital analyses of surface features [3], and thermochemical modeling of Venera and Vega basalts [4]. From these results, Venus and Earth have similar bulk chemistry and diversity of igneous rocks. However, the data from the Venera and Vega landers have large error bars compared with terrestrial geochemical analyses and do not provide mineralogy of the target rock, thereby making direct conclusions from this data challenging [e.g., 1, 2]. In order to make predictions about the types of magmas that could be on Venus, I will rely on crystallization experiments on terrestrial tholeiitic compositions. By comparing experimental results on terrestrial mafic basalts and natural terrestrial suites with the data from Venera and Vega, I constrain the types of igneous rocks that could be present on Venus, as well as the quality of data needed from future missions to distinguish the different suites. Extensive crystallization experiments have been conducted on terrestrial olivine tholeiites at varying pressures, temperatures, and water contents in order to understand the residual liquids produced by igneous differentiation [e.g., 5-10]. If similar processes of magma ponding and differentiation have occurred on Venus, then compositions similar to terrestrial igneous suites would be expected. The potential residual liquids produced by differentiation of a Venus tholeiite, based on experiments on analog compositions, range from rhyolites to phonolites, depending on pressure of crystallization and bulk water content. These experimental results are consistent with the interpretation of the Venera 13 analysis as a silica-undersaturated alkali basalt which suggests deep partial melting of a carbonated source region [11], while the identification of Venera 14 and Vega 2 as tholeiites suggests relatively shallow melting of a lherzolitic or peridotite source region. References: [1]. Kargel, J.S. et al. (1993) Icarus. 103(2): p. 253-275. [2] Treiman, A.H. (2007) in Exploring Venus as a Terrestrial Planet, Geophysical Monograph Series. p. 250. [3] Hashimoto, G.L., et al. (2008) JGR Planets. 113(E00B24): p. doi:10.1029/2008JE003134. [4] Shellnutt, J.G. (2013) JGR Planets. 118: p. 1350-1364, doi:10.1002/jgre.20094. [5] Spulber, S.D. and M.J. Rutherford (1983) Journal of Petrology. 24(1): p. 1-25. [6] Whitaker, M., et al. (2008) Bulletin of Volcanology. 70(3): p. 417-434. [7] Whitaker, M.L., et al. (2007) Journal of Petrology. 48(2): p. 365-393. [8] Nekvasil, H., et al. (2004) Journal of Petrology. 45(4): p. 693-721. [9] Green, D.H. (1970) Physics of the Earth and Planetary Interiors. 3: p. 221-235. [10] Filiberto, J. and Nekvasil H. (2003) GSA Abstracts with Programs. 35(6): p. 632. [11] Dasgupta, R., Hirschmann, M., and Smith, N. (2007) Journal of Petrology 48, 2093-2124.

  10. The inversion layer at the tropopause of the Venus atmosphere: new insights from the Radio Science Experiment (VeRa) onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Herrmann, M.; Oschlisniok, J.; Remus, S.; Tellmann, S.; Häusler, B.; Pätzold, M.

    2015-10-01

    The inversion layer at the tropopause of the Venus atmosphere is a very common and prominent feature in the vertical temperature profile at higher latitudes. The inversion layer is of particular interest because it separates the stratified troposphere from the highly variable mesosphere. The altitude range of the inversion layer is therefore a likely location for the formation of gravity waves [1]. The Radio Science Experiment (VeRa) onboard Venus Express [2,3] is capable to sound the Venus atmosphere from 100 km downward to 40 km [4,5] and delivered more than 800 vertical profiles of temperature, pressure and neutral number density at almost all local times and latitudes. The tropopause is typically located at 60 km altitude. Spatial changes of the refractive index over a short altitude range lead to multi-path effects which cannot be fully retrieved with common closed-loop recording methods. The development of a new data processing tool based on VeRa open loop data sets provided the necessary frequency resolution to fully resolve multipath effects occurring along a short range of 2 km at the tropopause location. The inversion layer presents itself up to 15K colder than commonly thought. The new results shall help to find a consistent picture of the Venus' thermal atmosphere structure and therefore help to improve atmospheric models.

  11. PC-403: Pioneer Venus multiprobe spacecraft mission operational characteristics document, volume 3

    NASA Technical Reports Server (NTRS)

    Barker, F. C.

    1978-01-01

    The Pioneer Venus spacecraft primary and backup operational modes and operational limitations for maneuvers, roll references transfer, attitude determination, spacecraft power discipline and spacecraft thermal discipline, are described. The functions and operations of the large and small probes, as well detailed performance in the normal operating modes and backup modes are presented.

  12. Radio science investigations by VeRa onboard the Venus Express spacecraft

    NASA Astrophysics Data System (ADS)

    Häusler, B.; Pätzold, M.; Tyler, G. L.; Simpson, R. A.; Bird, M. K.; Dehant, V.; Barriot, J.-P.; Eidel, W.; Mattei, R.; Remus, S.; Selle, J.; Tellmann, S.; Imamura, T.

    2006-11-01

    The Venus Express Radio Science Experiment (VeRa) uses radio signals at wavelengths of 3.6 and 13 cm ("X"- and "S"-band, respectively) to investigate the Venus surface, neutral atmosphere, ionosphere, and gravity field, as well as the interplanetary medium. An ultrastable oscillator (USO) provides a high quality onboard reference frequency source; instrumentation on Earth is used to record amplitude, phase, propagation time, and polarization of the received signals. Simultaneous, coherent measurements at the two wavelengths allow separation of dispersive media effects from classical Doppler shift. VeRa science objectives include the following: Determination of neutral atmospheric structure from the cloud deck (approximately 40 km altitude) to 100 km altitude from vertical profiles of neutral mass density, temperature, and pressure as a function of local time and season. Within the atmospheric structure, search for, and if detected, study of the vertical structure of localized buoyancy waves, and the presence and properties of planetary waves. Study of the H 2SO 4 vapor absorbing layer in the atmosphere by variations in signal intensity and application of this information to tracing atmospheric motions. Scintillation effects caused by radio wave diffraction within the atmosphere can also provide information on small-scale atmospheric turbulence. Investigation of ionospheric structure from approximately 80 km to the ionopause (<600 km), allowing study of the interaction between solar wind plasma and the Venus atmosphere. Observation of forward-scattered surface echoes obliquely reflected from selected high-elevation targets with anomalous radar properties (such as Maxwell Montes). More generally, such bistatic radar measurements provide information on the roughness and density of the surface material on scales of centimeters to meters. Detection of gravity anomalies, thereby providing insight into the properties of the Venus crust and lithosphere. Measurement of the Doppler shift, propagation time, and frequency fluctuations along the interplanetary ray path, especially during periods of superior conjunction, thus enabling investigation of dynamical processes in the solar corona.

  13. Preparation of In-Situ Data from the VEGA Balloon Mission at Venus for Archival on the PDS

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph; Crisp, David

    In 1985, the pioneering Soviet VEGA mission deployed two helium balloons into the atmosphere of Venus - the first, and so far only, planetary balloon mission. The balloons were tracked by an international network of radio telescopes, with a slow trickle of in-situ pressure, temperature, optical and wind measurements transmitted directly to Earth over 46 hours until battery depletion. While the key results of the mission were published at the time, the data have not been generally available in numerical form. Here we report an effort to archive the data on the NASA Planetary Data System (PDS). In fact the very low telemetry rate dictated by the direct-to-Earth communication and minimal energy budget on-board demanded heavy data compression/selection, and the reconstruction of the history of altitude and meteorological measurements had to address ambiguities in the lossy compression scheme. These challenges entailed a significant effort as part of the postdoctoral work of D. Crisp, and have not been documented fully in the literature. Here we summarize the mission and the telemetry data, together with the approach used to reconstruct/interpolate the archival dataset. This documentation and numerical files are being prepared for submission to the PDS Atmospheres Node, where it will be available to all.

  14. Retrieval and study of near-infrared surface emissivity maps of Themis Regio on Venus with VIRTIS-M (Venus Express)

    NASA Astrophysics Data System (ADS)

    Arnold, G.; Kappel, D.; Haus, R.; Tellez Pedroza, L.; Ivanov, M.

    2015-10-01

    Surface emissivity maps of Themis Regio on Venus have been derived from night side radiance spectra acquired by VIRTIS-M-R aboard Venus Express to explore the region's geology. The emissivity retrieval bases on a new approach combining a full radiative transfer model to simulate the spectra and a multi-spectrum retrieval algorithm to retrieve parameters that are common to a set of spectra. Assuming geologic activity to be negligible during the observations, the emissivity maps at 1.02 ?m, 1.10 ?m,and 1.18 ?m were retrieved as parameter vector that is common to many spectral image cubes covering Themis Regio. This approach provides the so far most precise semi-quantitative emissivity data at Themis Regio in the near IR range. Resulting emissivity maps display clear spatial variations relative to a referance value. We discuss the relevance of these variations to geologic structures and surficial properties.

  15. International Collaboration for Venus Exploration

    NASA Astrophysics Data System (ADS)

    Cutts, James; Limaye, Sanjay; Zasova, Ludmila; Wilson, Colin; Ocampo, Adriana; Glaze, Lori; Svedhem, H.; Nakamura, Masato; Widemann, Thomas

    The Venus Exploration Analysis Group (VEXAG) was established by NASA in July 2005 to identify scientific priorities and strategy for exploration of Venus. From the outset, VEXAG has been open to the international community participation and has followed the progress of the ESA Venus Express Mission and the JAXA Akasuki mission as well exploring potential broad international partnerships for Venus exploration through coordinated science and missions. This paper discussed three mechanisms through which these collaborations are being explored in which VEXAG members participate One pathway for international collaboration has been through COSPAR. The International Venus Exploration Working Group (IVEWG) was formed during the 2012 COSPAR general assembly in Mysore, India. Another potentially significant outcome has been the IVEWG’s efforts to foster a formal dialog between IKI and NASA/PSD on the proposed Venera D mission resulting in a meeting in June 2013 to be followed by a discussion at the 4MS3 conference in October 2013. This has now resulted in an agreement between NASA/PSD and IKI to form a joint Science Definition Team for Venera D. A second pathway has been through an international focus on comparative climatology. Scientists from the established space faring nations participated in a first international conference on Comparative Climatology for Terrestrial Planet (CCTP) in Boulder Colorado in June 2012 sponsored by several international scientific organizations. A second conference is planned for 2015. The Planetary Robotics Exploration Coordinating Group (PRECG) of International Academy of Astronautics (IAA) the IAA has been focusing on exploring affordable contributions to the robotic exploration by non-space-faring nations wishing to get involved in planetary exploration. PRECG has sponsored a two year study of Comparative Climatology for which Venus is the focal point and focused on engaging nations without deep space exploration capabilities. A third area of interchange has been the International Planetary Probe Workshop (IPPW) , now in its eleventh year, which brings together scientists, technologists and mission designers interested in the exploration of planets with atmospheres and particularly in the challenges of entry, descent and landing and sustained flight on other planets. IPPW has been an opportunity for developing the collaborations at a grass roots level. With both NASA and ESA favoring competitive rather than strategic approaches for selecting planetary missions (except for Moon and Mars), future collaboration on Venus exploration will involve flexible partnerships. However, international standards for proximity communication frequencies and protocols will be vital to international collaboration.

  16. The thermospheres of Titan and Venus: What can we learn from their comparison?

    NASA Astrophysics Data System (ADS)

    Mueller-Wodarg, I. C.; Yelle, R. V.

    2006-12-01

    The upper atmospheres Titan and Venus currently are and have for decades been subject of considerable interest. While the exploration of Venus began several decades ago and culminated in the Pioneer Venus and, most recently, the Venus Express missions, the exploration of Titan is in comparison still in its infancy. With the Cassini/Huygens mission returning a wealth of remote sensing and in-situ data from Titan, we now learn more about its atmosphere and find many unexpected features. How much can we learn about the new findings of Titan by comparing it to Venus? The fundamental questions that will be addressed in this talk are what processes drive the dynamics and energetics of both bodies' thermospheres, and how their global structures of neutral densities and temperatures compare. We will present recent Titan observations by Cassini/INMS and relate them to Pioneer Venus observations in an attempt to better understand Saturn's moon.

  17. Large scale atmospheric waves in the Venus mesosphere as seen by the VeRa Radio Science instrument on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, Silvia; Häusler, Bernd; Hinson, David P.; Tyler, G. Leonard; Andert, Thomas P.; Bird, Michael K.; Imamura, Takeshi; Pätzold, Martin; Remus, Stefan

    2015-04-01

    Atmospheric waves on all spatial scales play a crucial role in the redistribution of energy, momentum, and atmospheric constituent in planetary atmosphere and are thought to be involved in the development and maintenance of the atmospheric superrotation on Venus. The Venus Express Radio-Science Experiment VeRa sounded the Venus neutral atmosphere and ionosphere in Earth occultation geometry using the spacecraft radio subsystem at two coherent frequencies. Radial profiles of neutral number density, covering the altitude range 40-90 km, are then converted to vertical profiles of temperature and pressure, assuming hydrostatic equilibrium. The extensive VeRa data set enables us to study global scale atmospheric wave phenomena like thermal tides in the mesosphere and troposphere. A pronounced local time dependency of the temperature is found in the mesosphere at different altitude levels. Wave-2 structures dominate the low latitude range in the upper mesosphere while the higher latitudes show a strong wave-1 structure at the top of the cloud layer. The investigation of these wave structures provides valuable information about the energy transport in the atmosphere.

  18. Venus geology and tectonics - Hotspot and crustal spreading models and questions for the Magellan mission

    NASA Technical Reports Server (NTRS)

    Head, James W.; Crumpler, L. S.

    1990-01-01

    Spacecraft and ground-based observations of Venus have revealed a geologically young and active surface - with volcanoes, rift zones, orogenic belts and evidence for hotspots and crustal spreading - yet the processes responsible for these features cannot be identified from the available data. The Magellan spacecraft will acquire an unprecedented global data set which will provide a comprehensive and well resolved view of the planet. This will permit global geological mapping, an assessment of the style and relative importance of geological processes, and will help in the understanding of links between the surface geology and mantle dynamics of this earth-like planet.

  19. Return to Venus of AKATSUKI, the Japanese Venus Orbiter

    NASA Astrophysics Data System (ADS)

    Nakamura, M.; Iwagami, N.; Satoh, T.; Taguchi, M.; Watanabe, S.; Takahashi, Y.; Imamura, T.; Suzuki, M.; Ueno, M.; Yamazaki, A.; Fukuhara, T.; Yamada, M.; Ishii, N.; Ogohara, K.

    2011-12-01

    Japanese Venus Climate Orbiter 'AKATSUKI' (PLANET-C) was proposed in 2001 with strong support by international Venus science community and approved as an ISAS mission soon after the proposal. AKATSUKI and ESA's Venus Express complement each other in Venus climate study. Various coordinated observations using the two spacecraft have been planned. Also participating scientists from US have been selected. Its science target is to understand the climate of Venus. The mission life we expected was more than 2 Earth years in Venus orbit. AKATSUKI was successfully launched at 06:58:22JST on May 21, by H-IIA F17. After the separation from H-IIA, the telemetry from AKATSUKI was normally detected by DSN Goldstone station (10:00JST) and the solar cell paddles' expansion was confirmed. AKATSUKI was put into the 3-axis stabilized mode in the initial operation from Uchinoura station and the critical operation was finished at 20:00JST on the same day. The malfunction, which happened during the Venus Orbit Insertion (VOI) on7 Dec, 2010 is as follows. We set all commands on Dec. 5. Attitude control for Venus orbit insertion (VOI) was automatically done on Dec. 6. Orbital maneuver engine (OME) was fired 08:49 JST on Dec. 7. 1min. after firing the spacecraft went into the occultation region and we had no telemetry, but we expected to continuous firing for 12min. Recording on the spacecraft told us later that, unfortunately the firing continued just 152sec. and stopped. The reason of the malfunction of the OME was the blocking of check valve of the gas pressure line to push the fuel to the engine. We failed to make the spacecraft the Venus orbiter, and it is rotating the sun with the orbital period of 203 days. As the Venus orbit the sun with the period of 225 days, AKATSUKI has a chance to meet Venus again in 5 or 6 years depending on the orbit correction plan. Let us summarize the present situation of AKATSUKI. Most of the fuel still remains. But the condition of the propulsion system is unclear. ISAS is examining various scenarios of second Venus orbit insertion depending on the conditions of the check valve and the OME. Thermal condition during the extended cruise phase is severe. The solar flux (W/m2) to which the spacecraft is exposed from May 21, 2010 (Launch date) to the end of 2016. We expected about 2600W/m2 in the Venus orbit, but it is exposed to more than 3600W/m2 at perihelion (0.6AU from the sun). The temperatures of the instruments exposed to space gradually increased as the spacecraft approaching the perihelion. We tried to minimize the number of instruments whose temperatures exceed the allowed upper limits by letting a certain side of the spacecraft face to the sun. After passing the perihelion every instruments have been working normally. The degradation of the reflectivity of the outer film (MLI) during the extended cruise may influence the temperature tendency. Laboratory tests to evaluate the degradation are ongoing. We operate the test maneuver of the OME in September and hopefully the orbit maneuver in November, which leads the spacecraft close to Venus in 2015. We will report the result in the presentation.

  20. Requirements on Atmospheric Entry of Small Probes for Several Planets: Venus, Saturn, Neptune and Uranus in Preparation for the Future ESA Cosmic Vision Missions

    NASA Astrophysics Data System (ADS)

    Tomuta, D.; Rebuffat, D.; Larranaga, J.; Erd, C.; Bavdaz, M.; Falkner, P.

    2011-02-01

    In preparation for the ESA Cosmic Vision new call for medium class missions, a set of entry probes for inner and outer planets have been preliminary investigated by ESA using its Concurrent Design Facility. These Entry Probe missions are hypothetically assumed for launching time 2020-2035. A preliminary design of the probes arrived at a mass of about 300kg. In the following, the study is focused on the entry conditions for each of the planets Venus, Saturn, Neptune and Uranus with the aim to define the conditions for the Entry and Descent System (EDS) and its required technologies. For Venus case, two scenarios where considered: one where the entry probe is released during a typical gravity assist by a large interplanetary mission and another scenario featuring a stand alone mission targeted to Venus. During the entry in Venus atmosphere (mainly composed of CO2 (96.5%) and N2 (3.5%)), the probes are subjected to maximum heat fluxes of 60MW/m2, which is highly demanding in both scenarios. For the outer planet missions, only flyby scenarios with a targeted release of the probe were considered. The entry probes for the outer planets are subjected to heat fluxes above 100MW/m2, which is even more challenging the Thermal Protection Systems (TPS) and therefore requiring the use of special high temperature protection technology to prevent the destruction during the entry. ESA efforts for future missions are directed towards the development of an European Light Ablative Material (ELAM), though used in PEP study only for the Back Cover of the Entry Module. The TPS as well as both radiative and convective heat fluxes need simulations and verification by means of ground facility experiments. Based on the lessons learned from previous mission studies (mission to a near-Earth objects c.f. Marco Polo, Deimos Sample return), an Atmospheric Mars Sample Return is now under study. For sample return missions on return to Earth, a passive re-entry capsule delivering the sample(s) would need to withstand heat fluxes of around 15MW/m2. A MSR mission is currently investigated in cooperation with NASA to be launched in the mid 2020's and could take advantage of the TPS technology developments, such as ELAM. We present an overview of the assumptions and results of the Entry Probe mission studies and related technology developments.

  1. Geographic distribution of zonal wind and UV albedo at cloud top level from VMC camera on Venus Express: Influence of Venus topography through stationary gravity waves vertical propagation.

    NASA Astrophysics Data System (ADS)

    Bertaux, Jean-Loup; Khatunstsev, Igor; Hauchecorne, Alain; Markiewicz, Wojciech; Marcq, Emmanuel; Lebonnois, Sébastien; Patsaeva, Marina; Turin, Alexander

    2015-04-01

    UV images (at 365 nm) of Venus cloud top collected with VMC camera on board Venus Express allowed to derive a large number of wind measurements at altitude 67±2 km from tracking of cloud features in the period 2006-2012. Both manual (45,600) and digital (391,600) individual wind measurements over 127 orbits were analyzed showing various patterns with latitude and local time. A new longitude-latitude geographic map of the zonal wind shows a conspicuous region of strongly decreased zonal wind, a remarkable feature that was unknown up to now. While the average zonal wind near equator (from 5°S to 15°s) is -100.9 m/s in the longitude range 200-330°, it reaches -83.4 m/s in the range 60-100°, a difference of 17.5 m/s. When compared to the altimetry map of Venus, it is found that the zonal wind pattern is well correlated with the underlying relief in the region of Aphrodite Terra, with a downstream shift of about 30° (˜3,200 km). We interpret this pattern as the result of stationary gravity waves produced at ground level by the up lift of air when the horizontal wind encounters a mountain slope. These waves can propagate up to cloud top level, break there and transfer their momentum to the zonal flow. A similar phenomenon is known to operate on Earth with an influence on mesospheric winds. The LMD-GCM for Venus was run with or without topography, with and without a parameterization of gravity waves and does not display such an observed change of velocity near equator. The cloud albedo map at 365 nm varies also in longitude and latitude. We speculate that it might be the result of increased vertical mixing associated to wave breaking, and decreased abundance of the UV absorber which makes the contrast in images. The impact of these new findings on current super rotation theories remains to be assessed. This work was triggered by the presence of a conspicuous peak at 117 days in a time series of wind measurements. This is the length of the solar day as seen at the ground of Venus. Since VMC measurements are done preferably in a local time window centred on the sub-solar point, any parameter having a geographic longitude dependence will show a peak at 117 days.

  2. Mariner-Venus 1967

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Detailed information on the spacecraft performance, mission operations, and tracking and data acquisition is presented for the Mariner Venus 1967 and Mariner Venus 1967 extension projects. Scientific and engineering results and conclusions are discussed, and include the scientific mission, encounter with Venus, observations near Earth, and cruise phase of the mission. Flight path analysis, spacecraft subsystems, and mission-related hardware and computer program development are covered. The scientific experiments carried by Mariner 5 were ultraviolet photometer, solar plasma probe, helium magnetometer, trapped radiation detector, S-band radio occultation, dual-frequency radio propagation, and celestial mechanics. The engineering experience gained by converting a space Mariner Mars 1964 spacecraft into one flown to Venus is also described.

  3. Basic facts about Venus

    NASA Technical Reports Server (NTRS)

    Colin, L.

    1983-01-01

    Because of the disturbing influence of the earth's atmosphere on terrestrial and airborne telescopy, radiometry, thermal mapping, spectroscopy, polarimetry and radar astronomy of Venus, major improvements in the body of theory concerning that planet, began with the Mariner 2 planetary exploration program in 1962. The effect of spacecraft exploration culminated with the influx of data yielded by the Pioneer Venus and Venera 11 and 12 missions of 1978. Attention is presently given to the quantitative enhancement of widely accepted, basic facts about Venus that has resulted from the analysis of space probe data, together with an overview of the major features of past and planned planetary missions.

  4. Revealing the face of Venus: Magellan

    NASA Technical Reports Server (NTRS)

    1993-01-01

    An overview of the Magellan spacecraft and mission is presented. Topics covered include: a description of the Magellan spacecraft; Venus geology; Venus gravity; synthetic aperture radar; and radar sensing.

  5. The case for a deep-atmospheric in situ mission to address the highest priority Decadal Survey questions for Venus (Invited)

    NASA Astrophysics Data System (ADS)

    Atreya, S. K.; Garvin, J. B.; Glaze, L. S.; Campbell, B. A.; Fisher, M. E.; Flores, A.; Gilmore, M. S.; Johnson, N.; Kiefer, W. S.; Lorenz, R. D.; Mahaffy, P. R.; Ravine, M. A.; Webster, C. R.; Zolotov, M. Y.

    2013-12-01

    Current understanding of Venus lags behind that for Mars, with a major disparity of information concerning noble and trace gases and the small scale surface processes needed for comparative studies of terrestrial planet evolution. Despite global surface mapping by Magellan, discoveries by Venera landers, and ongoing atmospheric observations by the Venus Express (VEx) orbiter, significant questions about Venus remain unanswered. To place Venus into its proper context with respect to Mars and Earth, it is necessary to obtain new measurements that address top issues identified in the National Research Council (NRC) Solar System Decadal Survey: (1) evolution of the atmosphere, history of climate, and evidence of past hydrologic cycles; (2) history of volatiles and sedimentary cycles; and (3) planetary surface evolution. To answer these questions, new measurements are needed. First and foremost, in situ noble gas measurements are needed to constrain solar system formation and Venus evolution. In particular, the isotopic ratios of Xe and Kr can provide unique insights into planetary accretion. Isotopic measurements of nitrogen (15N/14N) will place important constraints on atmospheric loss processes. Current knowledge of this ratio has a substantial uncertainty of ×20%. VEx observations of hydrogen isotopes indicate the D/H ratio above the clouds is substantially greater than measured by Pioneer Venus, and varies with height. High precision measurements of the vertical distribution of the D/H isotopic ratio below the cloud layers will provide constraints on models of the climate history of water on Venus. The majority of atmospheric mass is located below the clouds. Current data suggest intense interaction among atmospheric gases down to the surface. The haze within the cloud region of unknown composition plays a central role in the radiative balance. Photochemically-derived species (H2SO4, OCS, CO, Sn) are subjected to thermochemical reactions below the clouds, especially within 30 km of the surface. Competing temperature-pressure dependent reactions and atmospheric circulation may cause vertical and latitudinal gradients of chemically-active trace gases (e.g., SO2, H2S, OCS, CO). Measurements of the chemical composition of the near-surface atmosphere can be used to evaluate the stability of primary and secondary minerals and can help to understand chemistry of atmosphere-surface interactions. However, concentrations of many trace species have never been measured below ~30 km, and multiple in situ measurements are required to evaluate chemical processes and cycles of volatiles, which can only be accomplished with deep entry probes. Current lack of understanding about Venus not only limits our understanding of evolutionary pathways Earth could experience, but also suggests that we are ill-equipped to understand the evolution of star systems with similar-sized planets.

  6. Introduction to the special issue on Venus exploration

    NASA Astrophysics Data System (ADS)

    Svedhem, H.; Wilson, C.; Piccioni, G.

    2015-08-01

    Venus Express ended its mission in December 2014 after an extraordinary successful eight and a half years at Venus. The first years of the mission concentrated on the original objectives of the mission, namely to study the dynamics, structure and chemistry of the atmosphere, to investigate the plasma environment and its interaction with the solar wind, and to study certain topics of the surface and the surface atmosphere interaction. The latter part of the mission was focussing on dedicated campaigns for the study of specific topics, often in coordination with ground based observations. The highly elliptical polar orbit permitted a study of all latitudes, particularly of the polar regions. The optimised payload and orbit of the mission, together with the systematic and long-term observations of the atmosphere has enabled a wealth of data to be analysed. It has already resulted in many exciting new findings and a significantly improved understanding of Venus, even if only a part of the data has been analysed so far. In the last year of the mission a two month long aerobraking campaign was performed, resulting in a valuable data set on the structure of the atmosphere down to below 130 km - a region difficult to sample with remote techniques, before the fuel ran out at the end of November 2014. This campaign also provided a lot of engineering and operational experience, useful for future missions that may use aerobraking techniques at Venus or other planets.

  7. Visualization of RelB expression and activation at the single-cell level during dendritic cell maturation in Relb-Venus knock-in mice.

    PubMed

    Seki, Takao; Yamamoto, Mami; Taguchi, Yuu; Miyauchi, Maki; Akiyama, Nobuko; Yamaguchi, Noritaka; Gohda, Jin; Akiyama, Taishin; Inoue, Jun-Ichiro

    2015-12-01

    RelB is activated by the non-canonical NF-?B pathway, which is crucial for immunity by establishing lymphoid organogenesis and B-cell and dendritic cell (DC) maturation. To elucidate the mechanism of the RelB-mediated immune cell maturation, a precise understanding of the relationship between cell maturation and RelB expression and activation at the single-cell level is required. Therefore, we generated knock-in mice expressing a fusion protein between RelB and fluorescent protein (RelB-Venus) from the Relb locus. The Relb(Venus) (/) (Venus) mice developed without any abnormalities observed in the Relb(-/-) mice, allowing us to monitor RelB-Venus expression and nuclear localization as RelB expression and activation. Relb(Venus) (/) (Venus) DC analyses revealed that DCs consist of RelB(-), RelB(low) and RelB(high) populations. The RelB(high) population, which included mature DCs with projections, displayed RelB nuclear localization, whereas RelB in the RelB(low) population was in the cytoplasm. Although both the RelB(low) and RelB(-) populations barely showed projections, MHC II and co-stimulatory molecule expression were higher in the RelB(low) than in the RelB(-) splenic conventional DCs. Taken together, our results identify the RelB(low) population as a possible novel intermediate maturation stage of cDCs and the Relb(Venus) (/) (Venus) mice as a useful tool to analyse the dynamic regulation of the non-canonical NF-?B pathway. PMID:26115685

  8. Venus Express: highlights of a four-year survey of our planet-neighbour

    NASA Astrophysics Data System (ADS)

    Titov, Dmitri; Svedhem, Håkan; Barabash, S.; Bertaux, J.-L.; Drossart, P.; Haeusler, B.; Korablev, O. I.; Markiewicz, W. J.; Paetzold, M.; Piccioni, G.; Taylor, F. W.; Vandaele, A.-C.; Zhang, T.

    Since April 2006 Venus Express has been performing a global survey of the remarkably dense, cloudy, and dynamic atmosphere of our near neighbour. A consistent picture of the climate on Venus is emerging on the basis of the new data, which enables us to provide an overview of the global temperature structure, the composition and its variations, the cloud morphology at various levels, the atmospheric dynamics and general circulation, and near-infrared emissions from trace species such as oxygen in the mesosphere. Vertical profiles of atmospheric tempera-ture in the mesosphere and upper troposphere show strong variability correlated with changes in the cloud top structure and many fine details indicating dynamical processes. Temperature sounding also shows that the cloud deck at 50-60 km is convectively unstable, in agreement with the analysis of UV images. Imaging also reveals strong latitudinal variations and significant temporal changes in the global cloud top morphology, which will inevitably modulate the solar energy deposited in the atmosphere. The cloud top altitude varies from ˜72 km in the low and middle latitudes to ˜64 km in the polar region, marking vast polar depressions that form as a result of the Hadley-type meridional circulation. Stellar and solar occultation measurements have revealed an extended upper haze of submicron particles and provided information on its optical properties. Solar occultation observations and deep atmosphere spectroscopy in several spectral transparency windows have quantified the distribution of the major trace gases H2O, SO2, CO, COS and their variations above and below the clouds, and so provided important input and validation for models of chemical cycles and dynamical transport. Cloud motion monitoring has characterised the mean state of the atmospheric circulation as well as its vari-ability. Low and middle latitudes show an almost constant zonal wind speed of 100+/-20 m/s at the cloud tops and vertical wind sheer of 2-3 m/s/km. Towards the pole, the wind speed drops quickly and the vertical shear vanishes. The meridional poleward wind ranges from 0 to about 15 m/s and there is some indication that it may change its direction at high latitudes. Comparison of the thermal wind field derived from temperature sounding to the cloud tracked winds confirms the approximate validity of cyclostrophic balance, at least in the latitude range from 30 S to 70S. Non-LTE infrared emissions in the lines of O2, NO, CO2, OH originating near the mesopause at 95-105 km altitude were detected and mapped. The data show that the peak intensity occurs close to the anti-solar point, which is consistent with current models of the thermospheric circulation.

  9. Power system comparison for the Pluto Express mission

    SciTech Connect

    Harty, R.B.

    1995-12-31

    This paper presents a comparison of three advanced radioisotope power systems, along with a down sized RTG for the Pluto Express mission. These three advanced radioisotope power systems were the Radioisotope Alkali Metal Thermal--to-Electric Converter (RAMTEC), Radioisotope Stirling, and Radioisotope Thermophotovoltaic (RTPV). For the Pluto Express mission, the power requirement at the end of the 10-y mission is 74 We. It was found that all three advanced power systems could meet the required end of mission power with two General Purpose Heat Source (GPHS) modules. The RTG required six modules to meet the power requirement. Only the RAMTEC and RTPV met the mass goal of 9.5 kg. The AMTEC has a radiator area more than a factor of 10 lower than the Stirling and RTPV power systems, which simplifies spacecraft integration.

  10. MESSENGER's Venus Flyby: Early Results

    NASA Astrophysics Data System (ADS)

    Solomon, Sean C.; MESSENGER Science Team

    2007-10-01

    The MESSENGER spacecraft flew by Venus on 5 June 2007 for a gravity assist to its subsequent encounters with Mercury. Closest approach was at 338 km altitude over 12°S, 165°E, near the boundary between the lowlands plains of Rusalka Planitia and the rifted uplands of Aphrodite Terra. All of the MESSENGER instruments operated during the flyby. The camera system imaged the night side in near-infrared bands and obtained color and higher-resolution monochrome mosaics of both the approaching and departing hemispheres. The ultraviolet and visible spectrometer obtained profiles of atmospheric species on the day and night sides as well as observations of the exospheric tail on departure. The visible and infrared spectrograph made observations of the planet near closest approach to gather compositional information on the upper atmosphere and clouds, and the laser altimeter carried out passive radiometry at 1064 nm and attempted to range to one or more cloud decks for several minutes near closest approach. That the European Space Agency's Venus Express mission was operating at the time of the flyby permitted the simultaneous observation of the planet from two independent spacecraft, a situation of particular value for characterization of the particle and field environment at Venus. MESSENGER's energetic particle and plasma spectrometer observed charged particle acceleration at the Venus bow shock and elsewhere, and the magnetometer provided measurements of the upstream interplanetary magnetic field (IMF), bow shock signatures, and pick-up ion waves as a reference for energetic particle and plasma observations by both spacecraft. The encounter also enabled two-point measurements of IMF penetration into the Venus ionosphere, primary plasma boundaries, and the near-tail region.

  11. Statistical Survey of Whistler Mode Signals in the Venus Ionosphere: A Proxy Study of Venus Lightning

    NASA Astrophysics Data System (ADS)

    Hart, R. A.; Russell, C. T.; Zhang, T. L.

    2015-10-01

    Venus Express has now completed its more than 8.5 year tenure in orbit around Venus. Throughout the mission it was in a 24 hour elliptical polar orbit with periapsis at ~80° latitude at orbital insertion in 2006. It then precessed near the pole in 2009 and ultimately finished its mission with periapsis at ~72° latitude (Figure 1). For the first few years the altitude of periapsis reached ~250 km above the surface, but later it commonly descended to ~165 km. In mid-2014 the spacecraft performed an aerobraking maneuver in which it descended further into the atmosphere down to ~130 km at its lowest point.Extremely low frequency(ELF) waves generated by lightning were most commonly detected when the spacecraft was near 250 km altitude. Here we present statistics of these lightning-induced ELF waves observed over the entire mission.

  12. A Retrospective Look at the Collected Results on the Large Scale Ionospheric Magnetic Fields at Venus

    NASA Astrophysics Data System (ADS)

    Luhmann, J. G.; Ma, Y.-J.; Villarreal, M.; Russell, C. T.; Zhang, T.-L.; Alvarez, K.

    2015-10-01

    We revisit the collected large scale ionospheric magnetic field results obtained by the Pioneer Venus Orbiter (PVO) and Venus Express (VEX) missions to ask how much we really understand about that field's global structure. To assist in this assessment we make use of several previously described MHD simulations of the solar wind interaction that reproduce its other observed features. These comparisons help to support our conceptual pictures in some cases, and to raise questions in others.

  13. Vesper - Venus Chemistry and Dynamics Orbiter - A NASA Discovery Mission Proposal: Submillimeter Investigation of Atmospheric Chemistry and Dynamics

    NASA Technical Reports Server (NTRS)

    Chin, Gordon

    2011-01-01

    Vesper conducts a focused investigation of the chemistry and dynamics of the middle atmosphere of our sister planet- from the base of the global cloud cover to the lower thermosphere. The middle atmosphere controls the stability of the Venus climate system. Vesper determines what processes maintain the atmospheric chemical stability, cause observed variability of chemical composition, control the escape of water, and drive the extreme super-rotation. The Vesper science investigation provides a unique perspective on the Earth environment due to the similarities in the middle atmosphere processes of both Venus and the Earth. Understanding key distinctions and similarities between Venus and Earth will increase our knowledge of how terrestrial planets evolve along different paths from nearly identical initial conditions.

  14. Express mission to Mars ESA/STARSEM-S.CORVAJA2003

    E-print Network

    _Express/ www.dlr.de/pf/en/desktopdefault.aspx/ www.esa.int www.nineplanets.org/mars.html www.uk2planets and the Exploration of the Red Planet Hyperion, 2005 Michael Hanlon The Real Mars Constable and Robinson 2004 Joseph M's first mission to Mars. Its role is to survey the planet from the topmost layer of the atmosphere down

  15. Seasons on Venus - cloud cover signatures

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay; Markiewicz, Wojciech; Krauss, Robert

    2015-04-01

    With the smallest obliquity and orbital eccentricity of any planet around the Sun, Venus is not generally expected to show any seasonal variations in its atmosphere. Careful analysis of the global images obtained by the Venus Monitoring Camera (VMC) on board European Space Agency's Venus Express orbiter from 12 June 2006 orbit 24) till 15 September 2014 (orbit 3043) reveal short term variations and a detectable periodic variation in the normalized intensity (reflectance) as well as in unit optical depth at a fixed local time at low latitudes as well as at high latitudes. VMC ultraviolet images were brightness normalized using Minnaert Law and the brightness at the sub-solar meridian at different latitudes in the southern hemisphere. The unit optical dept was inferred by precision location of the limb location in images acquired during the apoapsis portion of the orbit at range greater than ~ 30,000 km from Venus center. The temporal changes of the unit optical depth was monitored at fixed solar zenith angles and latitude. The seasonal signature is more pronounced at high latitudes compared to low latitudes. The data suggest that the variations in insolation due to heliocentric range and the small obliquity are responsible for the periodic changes in the Venus cloud cover. Concurrent changes in the cloud changes are also observed at other three wavelengths (550, 950 and 1050 nm) at which VMC obtained images, but the number of images at these wavelengths is much smaller. A secular decrease in the image brightness is observed over the life of the Venus Express mission, most likely due to the degradation of the some of the optical/sensor elements.

  16. The CO2 continuum absorption in the 1.10- and 1.18-?m windows on Venus from Maxwell Montes transits by SPICAV IR onboard Venus express

    NASA Astrophysics Data System (ADS)

    Fedorova, Anna; Bézard, Bruno; Bertaux, Jean-Loup; Korablev, Oleg; Wilson, Colin

    2015-08-01

    One of the difficulties in modeling Venus' nightside atmospheric windows is the need to apply CO2 continuum opacity due to collision-induced CO2 bands and/or extreme far wings of strong allowed CO2 bands. Characterizing the CO2 continuum absorption at near-IR wavelengths as well as searching for a possible vertical gradient of minor species near the surface require observations over different surface elevations. The largest change in altitude occurs during a passage above Maxwell Montes at high northern latitudes. In 2011, 2012 and 2013 the SPICAV instrument aboard the Venus Express satellite performed three sets of observations over Maxwell Montes with variation of surface altitude from -2 to 9 km in the 1.10, 1.18 and 1.28-?m windows. The retrieved CO2 continuum absorption for the 1.10- and 1.18-?m windows varies from 0.29 to 0.66×10-9 cm-1 amagat-2 and from 0.30 to 0.78×10-9 cm-1 amagat-2, respectively, depending on the assumed input parameters. The retrieval is sensitive to possible variations of the surface emissivity. Our values fall between the results of Bézard et al., (2009, 2011) based on VIRTIS-M observations and laboratory measurements by Snels et al. (2014). We can also conclude that the continuum absorption at 1.28 ?m can be constrained below 2.0×10-9 cm-1 amagat-2. Based on the 1.18 ?m window the constant H2O mixing ratio varying from 25.7+1.4-1.2 ppm to 29.4+1.6-1.4 ppm has been retrieved assuming the surface emissivity of 0.95 and 0.6, respectively. No firm conclusion from SPICAV data about the vertical gradient of water vapor content at 10-20 km altitude could be drawn because of low signal-to-noise ratio and uncertainties in the surface emissivity.

  17. Characterizing Volcanic Eruptions on Venus: Some Realistic (?) Scenarios

    NASA Technical Reports Server (NTRS)

    Stofan, E. R.; Glaze, L. S.; Grinspoon, D. H.

    2011-01-01

    When Pioneer Venus arrived at Venus in 1978, it detected anomalously high concentrations of SO2 at the top of the troposphere, which subsequently declined over the next five years. This decline in SO2 was linked to some sort of dynamic process, possibly a volcanic eruption. Observations of SO2 variability have persisted since Pioneer Venus. More recently, scientists from the Venus Express mission announced that the SPICAV (Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus) instrument had measured varying amounts of SO2 in the upper atmosphere; VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) measured no similar variations in the lower atmosphere (ESA, 4 April, 2008). In addition, Fegley and Prinn stated that venusian volcanoes must replenish SO2 to the atmosphere, or it would react with calcite and disappear within 1.9 my. Fegley and Tremain suggested an eruption rate on the order of approx 1 cubic km/year to maintain atmospheric SO2; Bullock and Grinspoon posit that volcanism must have occurred within the last 20-50 my to maintain the sulfuric acid/water clouds on Venus. The abundance of volcanic deposits on Venus and the likely thermal history of the planet suggest that it is still geologically active, although at rates lower than Earth. Current estimates of resurfacing rates range from approx 0.01 cubic km/yr to approx 2 cubic km/yr. Demonstrating definitively that Venus is still volcanically active, and at what rate, would help to constrain models of evolution of the surface and interior, and help to focus future exploration of Venus.

  18. Orbital Express mission operations planning and resource management using ASPEN

    NASA Astrophysics Data System (ADS)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel

    2008-04-01

    As satellite equipment and mission operations become more costly, the drive to keep working equipment running with less labor-power rises. Demonstrating the feasibility of autonomous satellite servicing was the main goal behind the Orbital Express (OE) mission. Like a tow-truck delivering gas to a car on the road, the "servicing" satellite of OE had to find the "client" from several kilometers away, connect directly to the client, and transfer fluid (or a battery) autonomously, while on earth-orbit. The mission met 100% of its success criteria, and proved that autonomous satellite servicing is now a reality for space operations. Planning the satellite mission operations for OE required the ability to create a plan which could be executed autonomously over variable conditions. As the constraints for execution could change weekly, daily, and even hourly, the tools used create the mission execution plans needed to be flexible and adaptable to many different kinds of changes. At the same time, the hard constraints of the plans needed to be maintained and satisfied. The Automated Scheduling and Planning Environment (ASPEN) tool, developed at the Jet Propulsion Laboratory, was used to create the schedule of events in each daily plan for the two satellites of the OE mission. This paper presents an introduction to the ASPEN tool, an overview of the constraints of the OE domain, the variable conditions that were presented within the mission, and the solution to operations that ASPEN provided. ASPEN has been used in several other domains, including research rovers, Deep Space Network scheduling research, and in flight operations for the NASA's Earth Observing One mission's EO1 satellite. Related work is discussed, as are the future of ASPEN and the future of autonomous satellite servicing.

  19. Venus cartography

    NASA Technical Reports Server (NTRS)

    Batson, R. M.; Kirk, R. L.; Edwards, Kathleen; Morgan, H. F.

    1994-01-01

    The entire surface of the planet Venus is being mapped at global and regional scales (1:50 million through 1:1.5 million) with synthetic aperture radar (SAR), radar altimeter, and radiometer measurements of physical properties from the Magellan spacecraft. The mapping includes SAR image mosaics, shaded relief maps, and topographic contour overlays made from altimetry data and by radargrammetric methods. Methods used include new techniques of radar image processing that became operational as a result of the Magellan mission. Special cartographic support products prepared by the USGS include: synthetic stereograms, color thematic maps of physical properties, digital shaded relief maps from opposite-look SAR, and topographic maps by radargrammetry. The area being mapped (at a resolution of 75 m/pixel) is roughly equivalent to that of Earth, including seafloors. The mapping is designed to support geologic and geophysical investigations.

  20. Magellan: The unveiling of Venus

    NASA Technical Reports Server (NTRS)

    1989-01-01

    In the late 1970s and early 1980s, the United States and the Soviet Union sent the Pioneer Venus and Venera spacecraft, respectively, to study Venus more closely and to image its surface with radar. These missions have answered many questions about Venus, but many more questions remain unanswered about the extent to which Venus' surface was shaped by volcanoes, plate tectonics, impact craters, and water and wind erosion. To help answer these remaining questions a new radar imaging spacecraft Magellan will be launched from the Space Shuttle. Magellan will spend eight months mapping most of the planet at a resolution nearly ten times better than any previous views of the surface. The mission of Magellan, the radar equipment, orbiting of Venus, planetary imaging, and surface exploration are discussed.

  1. Automated and Adaptive Mission Planning for Orbital Express

    NASA Technical Reports Server (NTRS)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel; Koblick, Darin

    2008-01-01

    The Orbital Express space mission was a Defense Advanced Research Projects Agency (DARPA) lead demonstration of on-orbit satellite servicing scenarios, autonomous rendezvous, fluid transfers of hydrazine propellant, and robotic arm transfers of Orbital Replacement Unit (ORU) components. Boeing's Autonomous Space Transport Robotic Operations (ASTRO) vehicle provided the servicing to the Ball Aerospace's Next Generation Serviceable Satellite (NextSat) client. For communication opportunities, operations used the high-bandwidth ground-based Air Force Satellite Control Network (AFSCN) along with the relatively low-bandwidth GEO-Synchronous space-borne Tracking and Data Relay Satellite System (TDRSS) network. Mission operations were conducted out of the RDT&E Support Complex (RSC) at the Kirtland Air Force Base in New Mexico. All mission objectives were met successfully: The first of several autonomous rendezvous was demonstrated on May 5, 2007; autonomous free-flyer capture was demonstrated on June 22, 2007; the fluid and ORU transfers throughout the mission were successful. Planning operations for the mission were conducted by a team of personnel including Flight Directors, who were responsible for verifying the steps and contacts within the procedures, the Rendezvous Planners who would compute the locations and visibilities of the spacecraft, the Scenario Resource Planners (SRPs), who were concerned with assignment of communications windows, monitoring of resources, and sending commands to the ASTRO spacecraft, and the Mission planners who would interface with the real-time operations environment, process planning products and coordinate activities with the SRP. The SRP position was staffed by JPL personnel who used the Automated Scheduling and Planning ENvironment (ASPEN) to model and enforce mission and satellite constraints. The lifecycle of a plan began three weeks outside its execution on-board. During the planning timeframe, many aspects could change the plan, causing the need for re-planning. These variable factors, ranging from shifting contact times to ground-station closures and required maintenance times, are discussed along with the flexibility of the ASPEN tool to accommodate changes to procedures and the daily or long-range plan, which contributed to the success of the mission. This paper will present an introduction to ASPEN, a more in-depth discussion on its use on the Orbital Express mission, and other relative work. A description of ground operations after the SRP deliveries were made is included, and we briefly discuss lessons learned from the planning perspective and future work.

  2. Ionospheric inversion of the Venus Express radio occultation data observed by Shanghai 25 m and New Norcia 35 m antennas

    NASA Astrophysics Data System (ADS)

    Zhang, Su-Jun; Jian, Nian-Chuan; Li, Jin-Ling; Ping, Jin-Song; Chen, Cong-Yan; Zhang, Ke-Fei

    2015-09-01

    Electron density profiles of Venus' ionosphere are inverted from the Venus Express (VEX) one-way open-loop radio occultation experiments carried out by the Shanghai 25 m antenna from November 2011 to January 2012 at solar maximum conditions and by the New Norcia 35 m antenna from August 2006 to June 2008 at solar intermediate conditions. The electron density profile (from 110 km to 400 km), retrieved from the X-band egress observation at the Shanghai station, shows a single peak near 147 km with a peak density of about 2 × 104 cm?3 at a solar zenith angle of 94°. As a comparison, the VEX radio science (VeRa) observations at the New Norcia station were also examined, including S- and X-band and dual-frequency data in the ingress mode. The results show that the electron density profiles retrieved from the S-band data are more analogous to the dual-frequency data in terms of the profile shape, compared with the X-band data. Generally, the S-band results slightly underestimate the magnitude of the peak density, while the X-band results overestimate it. The discrepancy in the X-band profile is probably due to the relatively larger unmodeled orbital errors. It is also expected that the ionopause height is sensitive to the solar wind dynamical pressure in high and intermediate solar activities, usually in the range of 200–1000 km on the dayside and much higher on the nightside. Structural variations (“bulges” and fluctuations) can be found in the electron density profiles during intermediate solar activity, which may be caused by the interaction of the solar wind with the ionosphere. Considerable ionizations can be observed in Venus' nightside ionosphere, which are unexpected for the Martian nightside ionosphere in most cases.

  3. Orbital Express Mission Operations Planning and Resource Management using ASPEN

    NASA Technical Reports Server (NTRS)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel

    2008-01-01

    As satellite equipment and mission operations become more costly, the drive to keep working equipment running with less man-power rises.Demonstrating the feasibility of autonomous satellite servicing was the main goal behind the Orbital Express (OE) mission. Planning the satellite mission operations for OE required the ability to create a plan which could be executed autonomously over variable conditions. The Automated-Scheduling and Planning Environment (ASPEN)tool, developed at the Jet Propulsion Laboratory, was used to create the schedule of events in each daily plan for the two satellites of the OE mission. This paper presents an introduction to the ASPEN tool, the constraints of the OE domain, the variable conditions that were presented within the mission, and the solution to operations that ASPEN provided. ASPEN has been used in several other domains, including research rovers, Deep Space Network scheduling research, and in flight operations for the ASE project's EO1 satellite. Related work is discussed, as are the future of ASPEN and the future of autonomous satellite servicing.

  4. AMTEC radioisotope power system for the Pluto Express mission

    SciTech Connect

    Ivanenok, J.F. III; Sievers, R.K.

    1995-12-31

    The Alkali Metal Thermal to Electric Converter (AMTEC) technology has made substantial advances in the last 3 years through design improvements and technical innovations. In 1993 programs began to produce an AMTEC cell specifically for the NASA Pluto Express Mission. A set of efficiency goals was established for this series of cells to be developed. According to this plan, cell {number_sign}8 would be 17% efficient but was actually 18% efficient. Achieving this goal, as well as design advances that allow the cell to be compact, has resulted in pushing the cell from an unexciting 2 W/kg and 2% efficiency to very attractive 40 W/kg and 18% measured efficiency. This paper will describe the design and predict the performance of a radioisotope powered AMTEC system for the Pluto Express mission.

  5. Chemical Weathering Kinetics of Basalt on Venus

    NASA Technical Reports Server (NTRS)

    Fegley, Bruce, Jr.

    1997-01-01

    The purpose of this project was to experimentally measure the kinetics for chemical weathering reactions involving basalt on Venus. The thermochemical reactions being studied are important for the CO2 atmosphere-lithosphere cycle on Venus and for the atmosphere-surface reactions controlling the oxidation state of the surface of Venus. These reactions include the formation of carbonate and scapolite minerals, and the oxidation of Fe-bearing minerals. These experiments and calculations are important for interpreting results from the Pioneer Venus, Magellan, Galileo flyby, Venera, and Vega missions to Venus, for interpreting results from Earth-based telescopic observations, and for the design of new Discovery class (e.g., VESAT) and New Millennium missions to Venus such as geochemical landers making in situ elemental and mineralogical analyses, and orbiters, probes and balloons making spectroscopic observations of the sub-cloud atmosphere of Venus.

  6. The Lavoisier mission : A system of descent probe and balloon flotilla for geochemical investigation of the deep atmosphere and surface of Venus

    NASA Astrophysics Data System (ADS)

    Chassefière, E.; Berthelier, J. J.; Bertaux, J.-L.; Quèmerais, E.; Pommereau, J.-P.; Rannou, P.; Raulin, F.; Coll, P.; Coscia, D.; Jambon, A.; Sarda, P.; Sabroux, J. C.; Vitter, G.; Le Pichon, A.; Landeau, B.; Lognonné, P.; Cohen, Y.; Vergniole, S.; Hulot, G.; Mandéa, M.; Pineau, J.-F.; Bézard, B.; Keller, H. U.; Titov, D.; Breuer, D.; Szego, K.; Ferencz, Cs.; Roos-Serote, M.; Korablev, O.; Linkin, V.; Rodrigo, R.; Taylor, F. W.; Harri, A.-M.

    Lavoisier mission is a joint effort of eight European countries and a technological challenge aimed at investigating the lower atmosphere and the surface of Venus. The mission consists of a descent probe and three balloons to be deployed below the cloud deck. Its main scientific objectives may be summarized as following : (i) composition of the deep atmosphere : noble gas (elemental/isotopic), molecular species (elemental/ isotopic), oxygen fugacity; vertical/horizontal/temporal variability; (ii) infrared spectroscopy and radiometry (molecular composition, radiative transfer); (iii) dynamics of the atmosphere : p, T, acceleration measurements, balloon localization through VLBI, meteorological events signed by acoustic waves, atmospheric mixing as imprinted on radioactive tracers; (iv) surface morphology and mineralogy through near infrared imaging on dayside, surface temperature through NIR imaging on nightside. Additional tentative objectives are search for (a) atmospheric electrical activity (optically, radioelectrically, acoustically), (b) crustal outgassing and/or volcanic activity : acoustic activity, horizontal/vertical distribution of radioactive tracers, (c) seismic activity : acoustic waves transmitted from crust to atmosphere, and (d) remanent and/or intrinsic magnetic field. Lavoisier was proposed to ESA in response to the F2/F3 mission Announcement of Opportunity at the beginning of 2000, but it was not selected for the assessment study. A wide international partnership was created for this occasion, including Finland (FMI), France (IPSL, MAGIE, Université Orsay, IPSN, INPG, CEA, IPGP, Obs. Paris-Meudon), Germany (MPAe, Univ. Muenster), Hungary (KFKI, Univ. Eotvos), Portugal (OAL), Russia (IKI), Spain (IAA), United Kingdom (Univ. Oxford).

  7. Some questions about the Venus atmosphere from past measurements

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay

    2015-11-01

    The many missions undertaken in the past half a century to explore Venus with fly-by spacecraft, orbiters, descending probes, landers and floating balloons, have provided us with a wealth of data. These data have been supplemented by many ground based observations at reflected solar wavelengths, short and long wave infrared to radio waves. Inter-comparison of the results from such measurements provide a good general idea of the global atmosphere. However, re-visiting these observations also raises some questions about the atmosphere that have not received much attention lately but deserve to be explored and considered for future measurements.These questions are about the precise atmospheric composition in the deep atmosphere, the atmospheric state in the lower atmosphere, the static stability of the lower atmosphere, the clouds and hazes, the nature of the ultraviolet absorber and wind speed and direction near the surface from equator to the pole. The answers to these questions are important for a better understanding of Venus, its weather and climate. The measurements required to answer these questions require careful and sustained observations within the atmosphere and from surface based stations. Some of these measurements should and can be made by large missions such as Venera-D (Russia), Venus Climate Mission (Visions and Voyages – Planetary Science Decadal Survey 2013-2022 or the Venus Flagship Design Reference Mission (NASA) which have been studied in recent years, but some have not been addressed in such studies. For example, the fact that the two primary constituents of the Venus atmosphere – Carbon Dioxide and Nitrogen are supercritical has not been considered so far. It is only recently that properties of binary supercritical fluids are being studied theoretically and laboratory validation is needed.With the end of monitoring of Venus by Venus Express orbiter in November 2014 after nearly a decade of observations and the imminent insertion of JAXA’s Akatsuki spacecraft into orbit around Venus, it is a good moment to consider the unanswered or unexplored questions about Venus.

  8. Ionospheric inversion of the Venus Express radio occultation data observed by Shanghai 25 m and New Norcia 35 m antennas

    E-print Network

    Zhang, Su-jun; Li, Jin-ling; Ping, Jin-song; Chen, Cong-yan; Zhang, Ke-fei

    2015-01-01

    Electron density profiles of the Venus' ionosphere are inverted from the Venus Express (VEX) one-way open-loop radio occultation experiments carried out by Shanghai 25 m antenna from November 2011 to January 2012 at solar maximum conditions and by New Norcia 35 m antenna from August 2006 to June 2008 at solar intermediate conditions. The electron density profile (from 110 km to 400 km) retrieved from the X-band egress observation at Shanghai station, shows a single peak near 147 km with a peak density of about $2 \\times 10^4 \\rm{cm}^{-3}$ at a solar zenith angle of 94$^{\\circ}$. As a comparison, the VEX radio science (VeRa) observations at New Norcia station were also examined, including S-, X-band and dual-frequency data in the ingress mode. The results show that the electron density profiles retrieved from the S-band data are more analogous to the dual-frequency data in the profile shape, compared with the X-band data. Generally, the S-band results slightly underestimate the magnitude of the peak density, w...

  9. Venus within ESA probe reach

    NASA Astrophysics Data System (ADS)

    2006-03-01

    Venus Express mission controllers at the ESA Space Operations Centre (ESOC) in Darmstadt, Germany are making intensive preparations for orbit insertion. This comprises a series of telecommands, engine burns and manoeuvres designed to slow the spacecraft down from a velocity of 29000 km per hour relative to Venus, just before the first burn, to an entry velocity some 15% slower, allowing the probe to be captured into orbit around the planet. The spacecraft will have to ignite its main engine for 50 minutes in order to achieve deceleration and place itself into a highly elliptical orbit around the planet. Most of its 570 kg of onboard propellant will be used for this manoeuvre. The spacecraft’s solar arrays will be positioned so as to reduce the possibility of excessive mechanical load during engine ignition. Over the subsequent days, a series of additional burns will be done to lower the orbit apocentre and to control the pericentre. The aim is to end up in a 24-hour orbit around Venus early in May. The Venus orbit injection operations can be followed live at ESA establishments, with ESOC acting as focal point of interest (see attached programme). In all establishments, ESA specialists will be on hand for interviews. ESA TV will cover this event live from ESOC in Darmstadt. The live transmission will be carried free-to-air. For broadcasters, complete details of the various satellite feeds are listed at http://television.esa.int. The event will be covered on the web at venus.esa.int. The website will feature regular updates, including video coverage of the press conference and podcast from the control room at ESA’s Operations Centre. Media representatives wishing to follow the event at one of the ESA establishments listed below are requested to fill in the attached registration form and fax it back to the place of their choice. For further information, please contact: ESA Media Relations Division Tel : +33(0)1.53.69.7155 Fax: +33(0)1.53.69.7690 Venus Express Orbit Insertion - Tuesday 11 April 2006 ESA/ESOC, Robert Bosch Strasse, 5 - Darmstadt (Germany) PROGRAMME 07:30 - Doors open 08:45 - Start of local event, welcome addresses 09:10 - ESA TV live from Mission Control Room (MCR) starts 09:17 - Engine burn sequence starts 09:45 - Occultation of spacecraft by Venus starts 09:55 - Occultation ends 10:07 - Main engine burn ends 10:20 - Address by Jean-Jacques Dordain, ESA’s Director General, and other officials Break and buffet Interview opportunities 11:30-12:15 - Press Conference Jean-Jacques Dordain, Director General, ESA Prof. David Southwood, Director of Science, ESA Gaele Winters, Director of Operations and Infrastructure, ESA Manfred Warhaut, Flight Operations Director, ESA Håkan Svedhem, Venus Express Project Scientist, ESA Don McCoy, Venus Express Project Manager, ESA 13:15 - End of event at ESOC ACCREDITATION REQUEST FORM Venus Express Orbit Insertion - ESA/ESOC Darmstadt - 11 April 2006 First name:___________________ Surname:_____________________ Media:______________________________________________________ Address: ___________________________________________________ ____________________________________________________________ Tel:_______________________ Fax: ___________________________ Mobile :___________________ E-mail: ________________________ I will be attending the Venus Express Orbit Insertion event at the following site: [ ] Germany Location: ESA/ESOC Address: Robert Bosch Strasse 5, Darmstadt, Germany Opening hours: 07:30 - 13:00 Contact: Jocelyne Landeau-Constantin, Tel: +49.6151.902.696 - Fax: +49.6151.902.961 [ ] France Location: ESA HQ Address: 8/10, rue Mario Nikis - Paris 15, France Opening hours: 08:00 - 13:00 Contact: Anne-Marie Remondin - Tel: +33(0)1.53.69.7155 - fax: +33(0)1.53.69.7690 [ ] The Netherlands Location: Newton Room, ESA/ESTEC Address: Keplerlaan 1, Noordwijk, The Netherlands Opening hours: 08:30 - 12:30 Contact: Michel van Baal, tel. + 31 71 565 3006, fax + 31 71 565 5728 [ ] Italy Location: ESA/ESRIN Address: Via Galileo Galilei, Frascati (Rome), Italy Opening hours: 07:00 - 14:

  10. Hesperos: A Post-Alpbach Mission Result

    NASA Astrophysics Data System (ADS)

    Koopmans, R.-J.; Bia?ek, A.; Donohoe, A.; Fernández Jiménez, M.; Frasl, B.; Gurciullo, A.; Kleinschneider, A.; ?osiak, A.; Mannel, T.; Muñoz Elorza, I.; Nilsson, D.; Oliveira, M.; Sørensen-Clark, P. M.; Timoney, R.; van Zelst, I.

    2015-10-01

    Despite similarities between Venus and Earth relatively little is known about its internal structure and processes. For this reason a geophysical mission to Venus is proposed. Its aim is to investigate the existence of tectonic activity, Venus internal structure and composition. The mission consists of an orbiter and balloon that will investigate Venus for a total of five years.

  11. Moon Express: Lander Capabilities and Initial Payload and Mission

    NASA Astrophysics Data System (ADS)

    Spudis, P.; Richards, R.; Burns, J. O.

    2013-12-01

    Moon Express Inc. is developing a common lander design to support the commercial delivery of a wide variety of possible payloads to the lunar surface. Significant recent progress has been made on lander design and configuration and a straw man mission concept has been designed to return significant new scientific and resource utilization data from the first mission. The Moon Express lander is derived from designs tested at NASA Ames Research Center over the past decade. The MX-1 version is designed to deliver 26 kg of payload to the lunar surface, with no global restrictions on landing site. The MX-2 lander can carry a payload of 400 kg and can deliver an upper stage (designed for missions that require Earth-return, such as sample retrieval) or a robotic rover. The Moon Express lander is powered by a specially designed engine capable of being operated in either monoprop or biprop mode. The concept for the first mission is a visit to a regional pyroclastic deposit on the lunar near side. We have focused on the Rima Bode dark mantle deposits (east of crater Copernicus, around 13 N, 4 W). These deposits are mature, having been exposed to solar wind for at least 3 Ga, and have high Ti content, suggesting high concentrations of implanted hydrogen. Smooth areas near the vent suggest that the ash beds are several tens of meters thick. The projected payload includes an imaging system to document the geological setting of the landing area, an APX instrument to provide major element composition of the regolith and a neutron spectrometer to measure the bulk hydrogen composition of the regolith at the landing site. Additionally, inclusion of a next generation laser retroreflector would markedly improve measurements of lunar librations and thus, constrain the dimensions of both the liquid and solid inner cores of the Moon, as well as provide tests of General Relativity. Conops are simple, with measurements of the surface composition commencing immediately upon landing. APX chemical analysis and neutron measurements would be completed within an hour or so. If any propellant remains after landing and a 'hop' to another site was undertaken, we can repeat these analyses at the second site, adding confidence that we have obtained representative measurements. Thus, the scientific goals of the first Moon Express mission are satisfied early and easily in the mission profile. This mission scenario provides significant scientific accomplishment for very little investment in payload and operations. Although minimally configured, the payload has been chosen to provide the most critical ground truth parameters for mapping hydrogen concentrations across the entire lunar surface. As hydrogen is a key element to the development of the Moon, understanding its occurrences in both non-polar and polar environments is critical. This mission achieves significant new scientific accomplishment as well as taking the first steps towards lunar presence and permanence.

  12. The structure of Venus' middle atmosphere and ionosphere.

    PubMed

    Pätzold, M; Häusler, B; Bird, M K; Tellmann, S; Mattei, R; Asmar, S W; Dehant, V; Eidel, W; Imamura, T; Simpson, R A; Tyler, G L

    2007-11-29

    The atmosphere and ionosphere of Venus have been studied in the past by spacecraft with remote sensing or in situ techniques. These early missions, however, have left us with questions about, for example, the atmospheric structure in the transition region from the upper troposphere to the lower mesosphere (50-90 km) and the remarkably variable structure of the ionosphere. Observations become increasingly difficult within and below the global cloud deck (<50 km altitude), where strong absorption greatly limits the available investigative spectrum to a few infrared windows and the radio range. Here we report radio-sounding results from the first Venus Express Radio Science (VeRa) occultation season. We determine the fine structure in temperatures at upper cloud-deck altitudes, detect a distinct day-night temperature difference in the southern middle atmosphere, and track day-to-day changes in Venus' ionosphere. PMID:18046400

  13. Six-year operation of the Venus Monitoring Camera (Venus Express): spatial and temporal variations of the properties of particles in upper clouds of Venus from the phase dependence of the near-IR brightness

    NASA Astrophysics Data System (ADS)

    Shalygina, O. S.; Petrova, E. V.; Markiewicz, W. J.

    2015-10-01

    Since May, 2006, the Venus Monitoring Camera (VMC) [1] has been imaging Venus in four narrow spectral channels centered at the wavelengths of 0.365 ?m (UV), 0.513 ?m (VIS), 0.965 ?m (NIR1), and 1.010 ?m (NIR2). It took around 300 000 images in four channels covering almost all the latitudes, including night and day sides. We analyze the whole set of the VMC data processed to October, 2012, i.e. the data from orbits 60 - 2 352 obtained in the phase angle range

  14. Venus Monthly Bibliography Compiled by Minh N. Le

    E-print Network

    Rathbun, Julie A.

    Venus Monthly Bibliography For: VEXAG Compiled by Minh N. Le June 1-July 1, 2015 Ando, H., T Waves in the Venus Atmosphere Obtained from Venus Express Radio Occultation Data: Evidence absorption spectra measured under simulated Venus conditions, Icarus, 254, 24-33, doi: http://dx.doi.org/10

  15. Dependence of longitudinal distribution of zonal wind and UV albedo at cloud top level on Venus topography from VMC camera onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Patsaeva, M.; Khatuntsev, I.; Bertaux, J.-L.; Turin, A.

    2015-10-01

    A set of UV images obtained by the Venus Monitoring Camera (VMC) [3] was processed by manual and digital methods [2]. Analysis of longitude-latitude distribution of the zonal wind for 49,700 (139 orbit) visual and 457,850 (722 orbit) digital individual wind measurements allowed us to find an influence of Venus topography on change of the average zonal wind in latitude range from 5°S to 15°S from -100.9 m/s in the longitude range 200-300° to -83.4 m/s in the range 60-100° [1]. Investigation of other latitude ranges by using a correlation method demonstrates that correlation shift depends on height of the obstacle streamlined by a flow. Dependence was found for both the average zonal stream and UV albedo averaged for the entire period of observations.

  16. Venus Atmosphere and Surface Explorer

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.; Hall, Jeff; Schofield, Tim

    2014-11-01

    ContextVenus is Earth’s twin planet, but it is an evil twin! To understand how Venus went wrong, to understand the terrestrial planets in our Solar System, those around other stars, and the future of the Earth… we must understand Venus history, evolution and current processes. This requires entering the Venus atmosphere and examining its surface. Future missions will land on Venus, but they need better characterization of its atmosphere and of possible landing sites. VASE can build on discoveries from previous missions, on technical advances in the last decades and on improved balloon technology. The hybrid mission links together a single vertical profile with two weeks of temporal and longitudinal data on a global scale. We can investigate the linked surface and atmosphere processes. We will measure the noble gases which retain indicators of Venus formation; clouds, winds, and chemistry that drive the current Venus processes; and take descent images that extend the Magellan RADAR results to sub-1m resolution, providing ground truth for Magellan’s global mapping and to characterize possible future landing sites.Science Objectives VASE will measure the complete inventory of atmospheric noble gas and light stable isotopes to constrain theories of planetary formation and evolution. It will take nested surface images on descent. It will provide the first complete atmospheric structure profile from clouds to surface of temperature, pressure and wind. VASE will measure with critical accuracy the trace and reactive gas composition profile from clouds to surface. VASE will map the surface emissivity along the surface below two balloon circumnavigations of Venus.Mission VASE is a hybrid Venus mission consisting of a large balloon and a small probe. It reaches Venus after a 4 month trip from Earth. The probe deploys from the entry vehicle and falls to surface in 1.5 hours. The balloon mission lasts 2 weeks, flying in the clouds at 55 km and circumnavigating Venus twice. The balloon communicates directly to Earth and serves as the telecom relay for the probe.

  17. Photochemical Control of the Distribution of Water and Sulphuric Acid Aerosols in the Clouds and Upper Haze of Venus with Comparison to Venus Express SOIR Observations

    NASA Astrophysics Data System (ADS)

    Parkinson, C. D.; Gao, P.; Yung, Y. L.; Bougher, S. W.; Bardeen, C.

    2014-12-01

    Observations of the middle and lower cloud layers of Venus has established the water vapour mixing ratio there as ~ 30-35 ppm (Ignatiev et al. 1997), while more recent data suggests that the water vapor mixing ratio of the upper haze of Venus is ~ 1 ppm (Bertaux et al. 2007). The transition region between these two regimes, the upper cloud, is an active site of photochemistry and production of sulfuric acid, which occurs through the formation of SO3 from the oxidation of SO2, and subsequent reactions between SO3 and water. These reactions have been shown by Parkinson et al. (2014a, submitted) as capable of causing an order of magnitude decrease of the water vapor mixing ratio in the upper cloud and upper haze if the SO2 mixing ratio at the upper cloud base were increased by only ~20%, as the resulting high SO3 concentrations rapidly react with any available water to form sulfuric acid. The opposite is true when water is in high abundance. This is likely to have profound effects on the sulfuric acid clouds and hazes themselves, as 1) the depletion of either species will decrease the production rate of sulfuric acid and 2) the saturation vapor pressure of the cloud droplets increases with decreasing water fraction, and thus a "drying" of the clouds may result in decreased cloud thickness. In this work we will use the Venus microphysical cloud models of Gao et al. (2014) and Parkinson et al. (2014b, submitted) to simulate the sulfuric acid clouds and hazes of Venus from 40 to 100 km altitude and evaluate how their structure and particle sizes depend on the background water vapor profile and sulfuric acid production rate as determined by Parkinson et al. (2014a, submitted). We also show how they respond to transient episodes of increased/decreased SO2/H2O mixing ratios and discuss the plausibility of possible causes, such as volcanic activity.

  18. MESSENGER's Venus Flyby: An Overview of Early Results

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.; Ho, G. C.; Izenberg, N. R.; Lawrence, D. J.; McClintock, W. E.; Neumann, G. A.; Prockter, L. M.; Raines, J. M.; Rhodes, E. A.; Robinson, M. S.; Slavin, J. A.; Smith, D. E.; Starr, R. D.; Zuber, M. T.; MESSENGER Science Team

    2007-12-01

    The MESSENGER spacecraft flew by Venus on 5 June 2007 for a gravity assist to its subsequent encounters with Mercury. Closest approach was at 338 km altitude over 12°S, 165°E, near the boundary between the lowland plains of Rusalka Planitia and the rifted uplands of Aphrodite Terra. All of the MESSENGER instruments operated during the flyby. The camera system imaged the night side in near-infrared bands and obtained color and higher-resolution monochrome mosaics of both the approaching and departing hemispheres. The ultraviolet and visible spectrometer obtained profiles of atmospheric species on the day and night sides as well as observations of the exospheric tail on departure. The visible and infrared spectrograph made observations of the Venus dayside near closest approach to gather compositional information on the upper atmosphere and clouds, and the laser altimeter carried out passive radiometry at 1064 nm and attempted to range to one or more cloud decks for several minutes near closest approach. The gamma-ray and neutron spectrometers observed gamma-rays and neutrons from the Venus atmosphere, providing information for planning the upcoming Mercury flybys and for calibration from a source of known composition. That the European Space Agency's Venus Express mission was operating at the time of the flyby permitted the simultaneous observation of the planet from two independent spacecraft, a situation of particular value for characterization of the particle and field environment at Venus. MESSENGER's energetic particle and plasma spectrometer observed charged particle acceleration at the Venus bow shock and elsewhere, and the magnetometer provided measurements of the upstream interplanetary magnetic field (IMF), bow shock signatures, and pick-up ion waves as a reference for energetic particle and plasma observations by both spacecraft. The encounter also enabled two-point measurements of IMF penetration into the Venus ionosphere, primary plasma boundaries, and the near-tail region.

  19. Orbital Express Mission Operations Planning and Resource Management using ASPEN

    NASA Technical Reports Server (NTRS)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Danny

    2008-01-01

    The Orbital Express satellite servicing demonstrator program is a DARPA program aimed at developing "a safe and cost-effective approach to autonomously service satellites in orbit". The system consists of: a) the Autonomous Space Transport Robotic Operations (ASTRO) vehicle, under development by Boeing Integrated Defense Systems, and b) a prototype modular next-generation serviceable satellite, NEXTSat, being developed by Ball Aerospace. Flexibility of ASPEN: a) Accommodate changes to procedures; b) Accommodate changes to daily losses and gains; c) Responsive re-planning; and d) Critical to success of mission planning Auto-Generation of activity models: a) Created plans quickly; b) Repetition/Re-use of models each day; and c) Guarantees the AML syntax. One SRP per day vs. Tactical team

  20. Extreme Environments Technologies for Probes to Venus and Jupiter

    NASA Technical Reports Server (NTRS)

    Balint, Tibor S.; Kolawa, Elizabeth A.; Peterson, Craig E.; Cutts, James A.; Belz, Andrea P.

    2007-01-01

    This viewgraph presentation reviews the technologies that are used to mitigate extreme environments for probes at Venus and Jupiter. The contents include: 1) Extreme environments at Venus and Jupiter; 2) In-situ missions to Venus and Jupiter (past/present/future); and 3) Approaches to mitigate conditions of extreme environments for probes with systems architectures and technologies.

  1. Robotic Technology for Exploration of Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2003-01-01

    Venus, the "greenhouse planet", is a scientifically fascinating place. A huge number of important scientific questions remain to be answered. Venus is sometimes called Earth's "sister planet" due to the fact that it is closest to the Earth in distance and similar to Earth in size. Despite its similarity to Earth, however, the climate of Venus is vastly different from Earth's. Understanding the atmosphere, climate, geology, and history of Venus could shed considerable light on our understanding of our own home planet. The surface of Venus is a hostile environment, with an atmosperic pressure of over 90 bar of carbon dioxide, temperature of 450 C, and shrouded in sulphuric-acid clouds. Venus has been explored by a number of missions from Earth, including the Russian Venera missions which landed probes on the surface, the American Pioneer missions which flew both orbiters and atmospheric probes to Venus, the Russian "Vega" mission, which floated balloons in the atmosphere of Venus, and most recently the American Magellan mission which mapped the surface by radar imaging. While these missions have answered basic questions about Venus, telling us the surface temperature and pressure, the elevations and topography of the continents, and the composition of the atmosphere and clouds, scientific mysteries still abound. Venus is of considerable interest to terrestrial atmospheric science, since of all the planets in the solar system, it is the closest analogue to the Earth in terms of atmosphere. Yet Venus' atmosphere is an example of "runaway greenhouse effect." Understanding the history and the dynamics of Venus' atmosphere could tell us considerable insight about the workings of the atmosphere of the Earth. It also has some interest to astrobiology-- could life have existed on Venus in an earlier, pre-greenhouse-effect phase? Could life still be possible in the temperate middle-atmosphere of Venus? The geology of Venus also has interest in the study of Earth. surface robot will require new technologies; specifically, it will require electronics, scientific instruments, power supplies, and mechanical linkages designed to operate at a temperature above 450 C-hot enough to melt the solder on a standard electronic circuit board. This will require devices made from advanced semiconductor materials, such as silicon carbide, or even new approaches, such as micro-vacuum tube electronics. Such materials are now being developed in the laboratory.

  2. Venus Transit 2004

    NASA Astrophysics Data System (ADS)

    Mayo, L. A.; Odenwald, S. F.

    2002-09-01

    December 6th, 1882 was the last transit of the planet Venus across the disk of the sun. It was heralded as an event of immense interest and importance to the astronomical community as well as the public at large. There have been only six such occurrences since Galileo first trained his telescope on the heavens in 1609 and on Venus in 1610 where he concluded that Venus had phases like the moon and appeared to get larger and smaller over time. Many historians consider this the final nail in the coffin of the Ptolemaic, Earth centered solar system. In addition, each transit has provided unique opportunities for discovery such as measurement and refinement of the astronomical unit, calculation of longitudes on the earth, and detection of Venus' atmosphere. The NASA Sun Earth Connection Education Forum in partnership with the Solar System Exploration Forum, DPS, and a number of NASA space missions is developing plans for an international education program centered around the June 8, 2004 Venus transit. The transit will be visible in its entirety from Europe and partially from the East Coast of the United States. We will use a series of robotic observatories including the Telescopes In Education network distributed in latitude to provide observations of the transit that will allow middle and high school students to calculate the A.U. through application of parallax. We will also use Venus transit as a probe of episodes in American history (e.g. 1769: revolutionary era, 1882: post civil war era, and 2004: modern era). Museums and planetariums in the US and Europe will offer real time viewing of the transit and conduct educational programs through professional development seminars, public lectures, and planetarium shows. We are interested in soliciting advice from the research community to coordinate professional research interests with this program.

  3. Venus Technology Plan Venus Technology Plan

    E-print Network

    Rathbun, Julie A.

    Venus Technology Plan May 2014 #12; ii Venus Technology Plan At the Venus Exploration and strategies for Venus exploration. To achieve this goal, three major tasks were defined: (1) update the document prioritizing Goals, Objectives and Investigations for Venus Exploration: (GOI), (2) develop

  4. The geological mapping project of the Mars Express mission

    NASA Astrophysics Data System (ADS)

    Ori, G. G.; di Iorio, A.

    2003-04-01

    The ESA mission Mars Express will send three instruments with geological mapping capability: HRSC, OMEGA, and MARSIS. The HRSC is a camera that will provide medium to high-resolution images (about 10m/pixel to 2m/pixel) in colour and stereo. OMEGA will provide maps of the surface mineralogy. MARSIS is a subsurface penetrating radar that will bring back data at depth in excess of 2000 metres. The data of Mars Express will provide a good opportunity to match different geological data sets including the subsurface geology. ESA through a peer-reviewed open competition has selected a project dealing with the geological mapping of the Mars Express data and their distribution in electronic formats. The aim of the project is to perform the geological mapping of the surface and subsurface data from HRSC, OMEGA, and MARSIS. The mapping operations will be coordinated by a scientific panel that will take care of the distribution among the scientific community of the tasks, the standardization of the geological nomenclature and of the interpretation of the data sets, and the evaluation and validation of the final products. The distribution of the tasks to the mapping teams will be done through a peer-reviewed process by the scientific panel. In order to have in Europe a community ready for such a kind of large-scale planetary project, a continuing educational programme is under way. This programme is financed by the Commission of the European Union, the European Space Agency, and the Italian Space Agency. Short Courses, summer schools, and workshop have been organized in 2001 and 2002 and more will be held in the next two years. The response to this activity has been positive and the interested community has grown up to cover a large number of scientists from State members of the European Union and other European Countries. The current activity of the project deals with two tasks. The first one is to provide the proper electronic configurations and formats (hardware and software) for the analysis of data and distribution of the final product; the second is the analysis of the data set in order to identify the proper procedure for the analysis. The most complex data set to deal with is the one from the MARSIS radar. These data are totally new and the procedure must be set from scratch. The data analysis will start after the public release of the data and will pursue until the completion of the mapping, later than the end of the extended mission.

  5. Future exploration of Venus (post-Pioneer Venus 1978)

    NASA Technical Reports Server (NTRS)

    Colin, L.; Evans, L. C.; Greeley, R.; Quaide, W. L.; Schaupp, R. W.; Seiff, A.; Young, R. E.

    1976-01-01

    A comprehensive study was performed to determine the major scientific unknowns about the planet Venus to be expected in the post-Pioneer Venus 1978 time frame. Based on those results the desirability of future orbiters, atmospheric entry probes, balloons, and landers as vehicles to address the remaining scientific questions were studied. The recommended mission scenario includes a high resolution surface mapping radar orbiter mission for the 1981 launch opportunity, a multiple-lander mission for 1985 and either an atmospheric entry probe or balloon mission in 1988. All the proposed missions can be performed using proposed space shuttle upper stage boosters. Significant amounts of long-lead time supporting research and technology developments are required to be initiated in the near future to permit the recommended launch dates.

  6. Context images for Venus Express radio occultations: a search for a dynamical-convective origin of cloud-top UV contrasts

    NASA Astrophysics Data System (ADS)

    Wilson, C.; Roos-Serote, M.; Tellmann, S.; Häusler, B.

    2015-10-01

    In this paper, we present a comparative analysis between data from the Venus Express Radio Science experiment (VeRa) and the Venus Monitoring Camera (VMC) UV channel. We compare the temperature structure derived from VeRa measurements with VMC-UV brightness at that same location, in search for any correlation. In the data analysed to date - which were all obtained at high Southern latitudes - we find no strong correlations, implying that we can find no evidence for a dynamical-convective origin of the UV contrasts at these latitudes. We suggest that the contrasts are formed at lower latitudes, a hypothesis which will be examined by looking at lower-latitude observations.

  7. Venus Phasing.

    ERIC Educational Resources Information Center

    Riddle, Bob

    1997-01-01

    Presents a science activity designed to introduce students to the geocentric and heliocentric models of the universe. Helps students discover why phase changes on Venus knocked Earth out of the center of the universe. (DKM)

  8. Exploring Venus.

    ERIC Educational Resources Information Center

    The Universe in the Classroom, 1985

    1985-01-01

    Presents basic information on the planet Venus answering questions on location, size, temperature, clouds, water, and daylight. A weather forecast for a typical day and revelations from radar experiments are also included. (DH)

  9. Electromagnetic waves observed on a flight over a Venus electrical storm

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Leinweber, H.; Zhang, T. L.; Daniels, J. T. M.; Strangeway, R. J.; Wei, H.

    2013-01-01

    The occurrence of electrical discharges in planetary atmospheres produces high temperatures and pressures enabling chemical reactions that are not possible under local thermodynamic equilibrium conditions. On Earth, electrical discharges in clouds produce nitric oxide. Similar abundances of nitric oxide exist in the Venus atmosphere, but the existence of extensive electrical activity in its substantive cloud system is not as firmly established. To determine the strength and occurrence rate of lightning, the Venus Express mission included dual magnetometers sampling at 128 Hz to detect the electromagnetic signals produced by lightning. We report herein evidence of the apparent overflight of electrical storms by the Venus Express spacecraft. These observations reveal two types of signals reaching the spacecraft: one in the ELF band that exhibits dispersion and travels along the magnetic field, and one in the ULF band that appears to travel vertically across the magnetic field from below.

  10. A balloon-borne stratospheric telescope for Venus observations

    NASA Astrophysics Data System (ADS)

    Young, Eliot F.; Bullock, Mark A.; Kraut, Alan; Orr, Graham; Swartzlander, Kevin; Wimer, Tony; Wong, Elton; Little, Patrick; Nakaya, Yusuke; Mellon, Russell; Germann, Lawrence

    2008-07-01

    A terrestrial stratospheric telescope is ideally suited for making infrared observations of Venus' night hemisphere during inferior conjunctions. The near-space environment at 35 km altitude has low daytime sky backgrounds and lack of atmospheric turbulence, both of which are necessary for observing Venus' night side at the diffraction limit when Venus is close to the Sun. In addition, the duration of the observing campaign will be around 3 weeks, a time period that is achievable by current long duration flights. The most important advantage, however, will be the ability of a balloonborne telescope to clearly image Venus' night side continuously throughout a 12-hr period (more for certain launch site latitudes), a capability that cannot be matched from the ground or from the Venus Express spacecraft currently in orbit around Venus. Future missions, such as the Japanese Venus Climate Orbiter will also not be able to achieve this level of synoptic coverage. This capability will provide a detailed, continuous look at evolving cloud distributions in Venus' middle and lower cloud decks through atmospheric windows at 1.74 and 2.3 ?m, which in turn will provide observational constraints on models of Venus' circulation. The science requirements propagate to several aspects of the telescope: a 1.4-m aperture to provide a diffraction limit of 0.3" at 1.74 ?m (to improve upon non-AO ground-based resolution by a factor of 2); a plate scale of 0.1" per pixel, which in turn requires an f/15 telescope for 13 ?m pixels; pointing and stability at the 0.05" level; stray light baffling; a field of view of 2 arc minutes; ability to acquire images at 1.26, 1.74 and 2.3 ?m and ability to operate aloft for three weeks at a time. The specific implementations of these requirements are outlined in this paper. Briefly, a 1.4-m Gregorian telescope is proposed, with stray light baffling at the intermediate focus. A three-stage pointing system is described, consisting of a coarse azimuthal rotator, a moderate pointing system based on a star tracker and ALT/AZ gimbals, and a fine pointing system based on analog photodiodes and a fine steering mirror. The science detectors are not discussed here, except to specify the requirement for moderate resolution (R > 1000) spectroscopy.

  11. Scientists Identify Exploration Goals for Venus

    NASA Astrophysics Data System (ADS)

    Kumar, Mohi

    2014-04-01

    Since the turn of the millennium, a large proportion of NASA's planetary science missions—including spacecraft and payloads on four orbiting missions and three rovers—has targeted Mars in preparation for future human missions to the red planet. Less studied, however, is Venus.

  12. Optimizing Aerobot Exploration of Venus

    NASA Astrophysics Data System (ADS)

    Ford, Kevin S.

    1997-03-01

    Venus Flyer Robot (VFR) is an aerobot; an autonomous balloon probe designed for remote exploration of Earth's sister planet in 2003. VFR's simple navigation and control system permits travel to virtually any location on Venus, but it can survive for only a limited duration in the harsh Venusian environment. To help address this limitation, we develop: (1) a global circulation model that captures the most important characteristics of the Venusian atmosphere; (2) a simple aerobot model that captures thermal restrictions faced by VFR at Venus; and (3) one exact and two heuristic algorithms that, using abstractions (1) and (2), construct routes making the best use of VFR's limited lifetime. We demonstrate this modeling by planning several small example missions and a prototypical mission that explores numerous interesting sites recently documented in the plane tary geology literature.

  13. The Magellan Venus explorer's guide

    NASA Technical Reports Server (NTRS)

    Young, Carolynn (editor)

    1990-01-01

    The Magellan radar-mapping mission to the planet Venus is described. Scientific highlights include the history of U.S. and Soviet missions, as well as ground-based radar observations, that have provided the current knowledge about the surface of Venus. Descriptions of the major Venusian surface features include controversial theories about the origin of some of the features. The organization of the Magellan science investigators into discipline-related task groups for data-analysis purposes is presented. The design of the Magellan spacecraft and the ability of its radar sensor to conduct radar imaging, altimetry, and radiometry measurements are discussed. Other topics report on the May 1989 launch, the interplanetary cruise, the Venus orbit-insertion maneuver, and the in-orbit mapping strategy. The objectives of a possible extended mission emphasize the gravity experiment and explain why high-resolution gravity data cannot be acquired during the primary mission. A focus on the people of Magellan reveals how they fly the spacecraft and prepare for major mission events. Special items of interest associated with the Magellan mission are contained in windows interspersed throughout the text. Finally, short summaries describe the major objectives and schedules for several exciting space missions planned to take us into the 21st century.

  14. Meeting Venus

    NASA Astrophysics Data System (ADS)

    Sterken, Christiaan; Aspaas, Per Pippin

    2013-06-01

    On 2-3 June 2012, the University of Tromsoe hosted a conference about the cultural and scientific history of the transits of Venus. The conference took place in Tromsoe for two very specific reasons. First and foremost, the last transit of Venus of this century lent itself to be observed on the disc of the Midnight Sun in this part of Europe during the night of 5 to 6 June 2012. Second, several Venus transit expeditions in this region were central in the global enterprise of measuring the scale of the solar system in the eighteenth century. The site of the conference was the Nordnorsk Vitensenter (Science Centre of Northern Norway), which is located at the campus of the University of Tromsoe. After the conference, participants were invited to either stay in Tromsoe until the midnight of 5-6 June, or take part in a Venus transit voyage in Finnmark, during which the historical sites Vardoe, Hammerfest, and the North Cape were to be visited. The post-conference program culminated with the participants observing the transit of Venus in or near Tromsoe, Vardoe and even from a plane near Alta. These Proceedings contain a selection of the lectures delivered on 2-3 June 2012, and also a narrative description of the transit viewing from Tromsoe, Vardoe and Alta. The title of the book, Meeting Venus, refers the title of a play by the Hungarian film director, screenwriter and opera director Istvan Szabo (1938-). The autobiographical movie Meeting Venus (1991) directed by him is based on his experience directing Tannhauser at the Paris Opera in 1984. The movie brings the story of an imaginary international opera company that encounters a never ending series of difficulties and pitfalls that symbolise the challenges of any multicultural and international endeavour. As is evident from the many papers presented in this book, Meeting Venus not only contains the epic tales of the transits of the seventeenth, eighteenth and nineteenth centuries, it also covers the conference participants' encounter with "Venus on the Sun" in historical archives as well as face-to-face at several locations in the Troms and Finnmark counties.

  15. Robotic Exploration of the Surface and Atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2004-01-01

    Venus, the "greenhouse planet", is a scientifically fascinating place. In many ways it can be considered "Earth's evil twin." A huge number of important scientific questions remain to be answered: 1) Before the runaway greenhouse effect, was early Venus temperate? 2) Did Venus once have an ocean? 3) What causes the geological resurfacing of the planet? 4) Is Venus still geologically active? 5) What is the "snow" on Venus mountaintops? 6) Can we learn about Earth's climate from Venus? 7) Is the atmosphere of Venus suitable for life? To address these and other scientific questions, a robotic mission to study the surface and atmosphere of Venus has been designed. The mission includes both surface robots, designed with an operational lifetime of 90 days on the surface of Venus, and also solar-powered airplanes to probe the middle atmosphere. At 450 Celsius, and with 90 atmospheres of pressure of carbon-dioxide atmosphere, the surface of Venus is a hostile place for operation of a probe. This paper will present the mission design, discuss the technology options for materials, power systems, electronics, and instruments, and present a short summary of the mission.

  16. A SemiAutomated Sky Survey for Slow Moving Objects Suitable for a Pluto Express Mission Encounter

    E-print Network

    Richmond, Michael W.

    A Semi­Automated Sky Survey for Slow Moving Objects Suitable for a Pluto Express Mission Encounter along the path of NASA's planned Pluto Express mission. Tests have been made to quantify our survey of the Pluto Express mission, and analysis resulted in the detection of two KBO candidates. The second data set

  17. Venus Monthly Bibliography Compiled by Minh N. Le

    E-print Network

    Rathbun, Julie A.

    Venus Monthly Bibliography For: VEXAG Compiled by Minh N. Le July 2015 Chai, L., et al. (2015), Solar zenith angle-dependent asymmetries in Venusian bow shock location revealed by Venus Express. S. Fu, and Y. S. Ge (2015), Evolution of Kelvin-Helmholtz instability at Venus in the presence

  18. Venus, Earth, Xenon

    NASA Astrophysics Data System (ADS)

    Zahnle, K. J.

    2013-12-01

    Xenon has been regarded as an important goal of many proposed missions to Venus. This talk is intended to explain why. Despite its being the heaviest gas found in natural planetary atmospheres, there is more evidence that Xe escaped from Earth than for any element apart from helium: (i) Atmospheric Xe is very strongly mass fractionated (at about 4% per amu) from any known solar system source. This suggests fractionating escape that preferentially left the heavy Xe isotopes behind. (ii) Xe is underabundant compared to Kr, a lighter noble gas that is not strongly mass fractionated in air. (iii) Radiogenic Xe is strongly depleted by factors of several to ~100 compared to the quantities expected from radioactive decay of primordial solar system materials. In these respects Xe on Mars is similar to Xe on Earth, but with one key difference: Xe on Mars is readily explained by a simple process like hydrodynamic escape that acts on an initially solar or meteoritic Xe. This is not so for Earth. Earth's Xe cannot be derived by an uncontrived mass fractionating process acting on any known type of Solar System Xe. Earth is a stranger, made from different stuff than any known meteorite or Mars or even the Sun. Who else is in Earth's family? Comets? We know nothing. Father Zeus? Data from Jupiter are good enough to show that jovian Xe is not strongly mass-fractionated but not good enough to determine whether Jupiter resembles the Earth or the Sun. Sister Venus? Noble gas data from Venus are incomplete, with Kr uncertain and Xe unmeasured. Krypton was measured by several instruments on several spacecraft. The reported Kr abundances are discrepant and were once highly controversial. These discrepancies appear to have been not so much resolved as forgotten. Xenon was not detected on Venus. Upper limits were reported for the two most abundant xenon isotopes 129Xe and 132Xe. From the limited data it is not possible to tell whether Venus's affinities lie with the solar wind, or with the chondrites, with Earth, or with none of the above. Modern spacecraft mass spectrometers are at least 100-fold more sensitive to noble gases. Sending such an instrument to Venus may be the last best hope for decrypting what Earth's noble gases have been trying to tell us.

  19. Search for ongoing volcanic activity on Venus

    NASA Astrophysics Data System (ADS)

    Shalygin, E. V.; Markiewicz, W. J.; Basilevsky, A. T.; Titov, D. V.; Ignatiev, N. I.; Head, J. W.

    2015-10-01

    We report results of systematical analysis of the whole data-set obtained by the Venus Monitoring Camera(VMC)on-board the Venus Express (VEx) spacecraft at the night side of the planet. In this data set we searched for transient bright events which exhibit behaviour of a hot spot on the surface.

  20. Mariner Venus-Mercury 1973 Project. Volume 1: Venus and Mercury 1 Encounters

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The primary mission report includes the Venus encounter and the first Mercury encounter. Plans and activities undertaken to successfully achieve the mission objectives are described. Operational activities are identified by mission operation system functions, providing a brief summary of each discipline. Spacecraft performance is summarized by subsystems.

  1. The Venus environment

    SciTech Connect

    Not Available

    1982-08-01

    Attention is given to noble gases in planetary atmospheres, the photochemistry of the stratosphere of Venus, the chemistry of metastable species in the Venusian ionosphere, the Venus ionosphere at grazing incidence of solar radiation, disappearing ionospheres on the nightside of Venus, and the observed composition of the ionosphere of Venus. Other investigations considered are concerned with the predicted electrical conductivity between 0 and 80 km in the Venusian atmosphere, sulfuric acid vapor and other cloud-related gases in the Venus atmosphere, the composition and vertical structure of the lower cloud deck on Venus, amorphous sulfur as the ultraviolet absorber on Venus, and polarization studies of the Venus UV contrasts. A description is provided of topics related to temporal variability of ultraviolet cloud features in the Venus stratosphere, zonal mean circulation at the cloud level on Venus, the influence of thermospheric winds on exospheric hydrogen on Venus, and an analysis of Venus gravity data.

  2. Observations of quasi-perpendicular propagating electromagnetic waves near the ionopause current sheet of Venus

    E-print Network

    California at Berkeley, University of

    sheet of Venus H. Y. Wei,1 C. T. Russell,1 J. T. M. Daniels,1 T. L. Zhang,2 R. J. Strangeway,1 and J. G. [1] Due to the lack of an intrinsic magnetic field at Venus, the Venus ionosphere acts of the solar wind magnetic fields into the ionosphere. The Venus Express magnetometer occasionally observes

  3. First laboratory high-temperature emissivity measurements of Venus analog measurements in the near-infrared atmospheric windows

    NASA Astrophysics Data System (ADS)

    Helbert, J.; Maturilli, A.; Ferrari, S.; Dyar, M. D.; Smrekar, S. E.

    2014-12-01

    The permanent cloud cover of Venus prohibits observation of the surface with traditional imaging techniques over most of the visible spectral range. Venus' CO2 atmosphere is transparent exclusively in small spectral windows near 1 ?m. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) team on the European Space Agency Venus-Express mission have recently used these windows successfully to map the southern hemisphere from orbit. VIRTIS is showing variations in surface brightness, which can be interpreted as variations in surface emissivity. Deriving surface composition from these variations is a challenging task. Comparison with laboratory analogue spectra are complicated by the fact that Venus has an average surface temperature of 730K. Mineral crystal structures and their resultant spectral signatures are notably affected by temperature, therefore any interpretations based on room temperature laboratory spectra database can be misleading. In order to support the interpretation of near-infrared data from Venus we have started an extensive measurement campaign at the Planetary Emissivity Laboratory (PEL, Institute of Planetary Research of the German Aerospace Center, Berlin). The PEL facility, which is unique in the world, allows emission measurements covering the 1 to 2 ?m wavelength range at sample temperatures of up to 770K. Conciliating the expected emissivity variation between felsic and mafic minerals with Venera and VEGA geochemical data we have started with a set of five analog samples. This set includes basalt, gneiss, granodiorite, anorthosite and hematite, thus covering the range of mineralogies. Preliminary results show significant spectral contrast, thus allowing different samples to be distinguished with only 5 spectral points and validating the use of thermal emissivity for investigating composition. This unique new dataset from PEL not only allows interpretation of the Venus Express VIRTIS data but also provide a baseline for considering new instrument designs for future Venus missions.

  4. Hot Flow Anomalies at Venus

    NASA Technical Reports Server (NTRS)

    Collinson, G. A.; Sibeck, David Gary; Boardsen, Scott A.; Moore, Tom; Barabash, S.; Masters, A.; Shane, N.; Slavin, J.A.; Coates, A.J.; Zhang, T. L.; Sarantos, M.

    2012-01-01

    We present a multi-instrument study of a hot flow anomaly (HFA) observed by the Venus Express spacecraft in the Venusian foreshock, on 22 March 2008, incorporating both Venus Express Magnetometer and Analyzer of Space Plasmas and Energetic Atoms (ASPERA) plasma observations. Centered on an interplanetary magnetic field discontinuity with inward convective motional electric fields on both sides, with a decreased core field strength, ion observations consistent with a flow deflection, and bounded by compressive heated edges, the properties of this event are consistent with those of HFAs observed at other planets within the solar system.

  5. Pioneer Venus orbiter electron temperature probe

    NASA Technical Reports Server (NTRS)

    Brace, Larry H.

    1994-01-01

    This document lists the scientific accomplishments of the Orbiter Electron Temperature Probe (OETP) group. The OETP instrument was fabricated in 1976, integrated into the PVO spacecraft in 1977, and placed in orbit about Venus in December 1978. The instrument operated flawlessly for nearly 14 years until PVO was lost as it entered the Venusian atmosphere in October 1992. The OETP group worked closely with other PVO investigators to examine the Venus ionosphere and its interactions with the solar wind. After the mission was completed we continued to work with the scientist selected for the Venus Data Analysis Program (VDAP), and this is currently leading to additional publications.

  6. Venus reconsidered.

    PubMed

    Kaula, W M

    1995-12-01

    The Magellan imagery shows that Venus has a crater abundance equivalent to a surface age of 300 million to 500 million years and a crater distribution close to random. Hence, the tectonics of Venus must be quiescent compared to those of Earth in the last few 100 million years. The main debate is whether the decline in tectonic activity on Venus is closer to monotonic or episodic, with enhanced tectonism and volcanism yet to come. The former hypothesis implies that most radioactive heat sources have been differentiated upward; the latter, that they have remained at depth. The low level of activity in the last few 100 million years inferred from imagery favors the monotonic hypothesis; some chemical evidence, particularly the low abundance of radiogenic argon, favors the episodic. A problem for both hypotheses is the rapid decline of thermal and tectonic activity some 300 million to 500 million years ago. The nature of the convective instabilities that caused the decline, and their propagation, are unclear. PMID:7491490

  7. Venus mapping

    NASA Technical Reports Server (NTRS)

    Batson, R. M.; Morgan, H. F.; Sucharski, Robert

    1991-01-01

    Semicontrolled image mosaics of Venus, based on Magellan data, are being compiled at 1:50,000,000, 1:10,000,000, 1:5,000,000, and 1:1,000,000 scales to support the Magellan Radar Investigator (RADIG) team. The mosaics are semicontrolled in the sense that data gaps were not filled and significant cosmetic inconsistencies exist. Contours are based on preliminary radar altimetry data that is subjected to revision and improvement. Final maps to support geologic mapping and other scientific investigations, to be compiled as the dataset becomes complete, will be sponsored by the Planetary Geology and Geophysics Program and/or the Venus Data Analysis Program. All maps, both semicontrolled and final, will be published as I-maps by the United States Geological Survey. All of the mapping is based on existing knowledge of the spacecraft orbit; photogrammetric triangulation, a traditional basis for geodetic control on planets where framing cameras were used, is not feasible with the radar images of Venus, although an eventual shift of coordinate system to a revised spin-axis location is anticipated. This is expected to be small enough that it will affect only large-scale maps.

  8. Exploration at the Edge of the Solar System: The Pluto-Kuiper Express Mission (Invited)

    NASA Astrophysics Data System (ADS)

    Terrile, R. J.

    1999-09-01

    The Pluto-Kuiper Express mission is one component of the Outer Planets/Solar Probe Project which is part of the exploration strategy laid out in the Solar System Exploration Roadmap. The first three missions of this project are the Europa Orbiter, Pluto-Kuiper Express and the Solar Probe. All require challenging new technologies and the ability to operate in deep space and at Jupiter. Use of common management and design approaches, avionics, and mission software is planned to reduce the costs of the three missions. The Pluto-Kuiper Express mission is planned to launch in 2004 and is designed to provide the first reconnaissance of the Solar System's most distant planet, Pluto, and it, moon Charon. A gravity assist from Jupiter will allow an 8-year flight time to Pluto and the possibility of encountering one or more Edgeworth-Kuiper Belt objects after the Pluto encounter. The primary science objectives for the mission include characterizing the global geology and geomorphology of Pluto and Charon, mapping their surface composition and characterizing Pluto's neutral atmosphere and its escape rate. This mission is currently soliciting scientific investigations through a NASA Announcement of Opportunity.

  9. The impact of a slow interplanetary coronal mass ejection on Venus

    NASA Astrophysics Data System (ADS)

    Collinson, Glyn A.; Grebowsky, Joseph; Sibeck, David G.; Jian, Lan K.; Boardsen, Scott; Espley, Jared; Hartle, Dick; Zhang, Tielong L.; Barabash, Stas; Futaana, Yoshifumi; Kollmann, Peter

    2015-05-01

    We present Venus Express observations of the impact of a slow interplanetary coronal mass ejection (ICME), which struck Venus on 23 December 2006, creating unusual quasi steady state upstream conditions for the 2 h close to periapsis: an enhanced (˜ nT) interplanetary magnetic field (IMF), radially aligned with the Sun-Venus line; and a dense (˜ cm-3) solar wind. Contrary to our current understanding and expectations, the ionosphere became partially demagnetized. We also find evidence for shocked sheathlike solar wind protons and electrons in the wake of Venus, and powerful (? nT2/Hz) foreshock whistler mode waves radiating from the bow shock at an unexpectedly low frequency (0.6 Hz). Given the abnormally high density of escaping heavy ions at the magnetopause boundary (295 cm-3, one of the highest of the whole mission) and the enhanced density of escaping heavy ions in the wake, we find that even weak ICMEs with no driving shocks can increase atmospheric loss rates at Venus and suggests that the Bx component of the IMF may be a factor in atmospheric escape rates.

  10. Hypothetical flora and fauna of Venus

    NASA Astrophysics Data System (ADS)

    Ksanfomality, L. V.

    2014-12-01

    Hypothetical habitability of some of extrasolar planets is a fundamental question of science. Some of exoplanets possess physical conditions close to those of Venus. Therefore, the planet Venus, with its dense and hot (735 K) oxygen-free atmosphere of CO2, having a high pressure of 9.2 MPa at the surface, can be a natural laboratory for this kind of studies. The only existing data on the planet's surface are still the results obtained by the Soviet VENERA landers in the 1970s and 1980s. The TV experiments of Venera-9 and 10 (October, 1975) and Venera-13 and 14 (March, 1982) delivered 41 panoramas of Venus surface (or their fragments). There have not been any similar missions to Venus in the subsequent 39 and 32 years. In the absence of new landing missions to Venus, the VENERA panoramas have been re-processed. The results of these missions are studied anew. A dozen of relatively large objects, from a decimeter to half a meter in size, with an unusual morphology have been found which moved very slowly or changed slightly their shape. Their emergence by chance could hardly be explained by noise. Certain unusual findings that have similar structure were found in different areas of the planet. This paper presents the last results obtained of a search for hypothetical flora and fauna of Venus.

  11. Interplanetary mission planning

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A long range plan for solar system exploration is presented. The subjects discussed are: (1) science payload for first Jupiter orbiters, (2) Mercury orbiter mission study, (3) preliminary analysis of Uranus/Neptune entry probes for Grand Tour Missions, (4) comet rendezvous mission study, (5) a survey of interstellar missions, (6) a survey of candidate missions to explore rings of Saturn, and (7) preliminary analysis of Venus orbit radar missions.

  12. Study and Implementation of the End-to-End Data Pipeline for the Virtis Imaging Spectrometer Onbaord Venus Express: "From Science Operations Planning to Data Archiving and Higher Lever Processing"

    NASA Astrophysics Data System (ADS)

    Cardesín Moinelo, Alejandro

    2010-04-01

    This PhD Thesis describes the activities performed during the Research Program undertaken for two years at the Istituto Nazionale di AstroFisica in Rome, Italy, as active member of the VIRTIS Technical and Scientific Team, and one additional year at the European Space Astronomy Center in Madrid, Spain, as member of the Mars Express Science Ground Segment. This document will show a study of all sections of the Science Ground Segment of the Venus Express mission, from the planning of the scientific operations, to the generation, calibration and archiving of the science data, including the production of valuable high level products. We will present and discuss here the end-to-end diagram of the ground segment from the technical and scientific point of view, in order to describe the overall flow of information: from the original scientific requests of the principal investigator and interdisciplinary teams, up to the spacecraft, and down again for the analysis of the measurements and interpretation of the scientific results. These scientific results drive to new and more elaborated scientific requests, which are used as feedback to the planning cycle, closing the circle. Special attention is given here to describe the implementation and development of the data pipeline for the VIRTIS instrument onboard Venus Express. During the research program, both the raw data generation pipeline and the data calibration pipeline were developed and automated in order to produce the final raw and calibrated data products from the input telemetry of the instrument. The final raw and calibrated products presented in this work are currently being used by the VIRTIS Science team for data analysis and are distributed to the whole scientific community via the Planetary Science Archive. More than 20,000 raw data files and 10,000 calibrated products have already been generated after almost 4 years of mission. In the final part of the Thesis, we will also present some high level data processing methods developed for the Mapping channel of the VIRTIS instrument. These methods have been implemented for the generation of high level global maps of measured radiance over the whole planet, which can then be used for the understanding of the global dynamics and morphology of the Venusian atmosphere. This method is currently being used to compare different emissions probing at different altitudes from the low cloud layers up to the upper mesosphere, by using the averaged projected values of radiance observed by the instrument, such as the near infrared windows at 1.7 ?m and 2.3?m, the thermal region at 3.8?m and 5?m plus the analysis of particular emissions in the night and day side of the planet. This research has been undertaken under guidance and supervision of Giuseppe Piccioni, VIRTIS co-Principal Investigator, with support of the entire VIRTIS technical and scientific team, in particular of the Archiving team in Paris (LESIA-Meudon). The work has also been done in close collaboration with the Science and Mission Operations Centres in Madrid and Darmstadt (European Space Agency), the EGSE software developer (Techno Systems), the manufacturer of the VIRTIS instrument (Galileo Avionica) and the developer of the VIRTIS onboard software (DLR Berlin). The outcome of the technical and scientific work presented in this thesis is currently being used by the VIRTIS team to continue the investigations on the Venusian atmosphere and plan new scientific observations to improve the overall knowledge of the solar system. At the end of this document we show some of the many technical and scientific contributions, which have already been published in several international journals and conferences, and some articles of the European Space Agency used for public outreach.

  13. The Plains of Venus

    NASA Astrophysics Data System (ADS)

    Sharpton, V. L.

    2013-12-01

    Volcanic plains units of various types comprise at least 80% of the surface of Venus. Though devoid of topographic splendor and, therefore often overlooked, these plains units house a spectacular array of volcanic, tectonic, and impact features. Here I propose that the plains hold the keys to understanding the resurfacing history of Venus and resolving the global stratigraphy debate. The quasi-random distribution of impact craters and the small number that have been conspicuously modified from the outside by plains-forming volcanism have led some to propose that Venus was catastrophically resurfaced around 725×375 Ma with little volcanism since. Challenges, however, hinge on interpretations of certain morphological characteristics of impact craters: For instance, Venusian impact craters exhibit either radar dark (smooth) floor deposits or bright, blocky floors. Bright floor craters (BFC) are typically 100-400 m deeper than dark floor craters (DFC). Furthermore, all 58 impact craters with ephemeral bright ejecta rays and/or distal parabolic ejecta patterns have bright floor deposits. This suggests that BFCs are younger, on average, than DFCs. These observations suggest that DFCs could be partially filled with lava during plains emplacement and, therefore, are not strictly younger than the plains units as widely held. Because the DFC group comprises ~80% of the total crater population on Venus the recalculated emplacement age of the plains would be ~145 Ma if DFCs are indeed volcanically modified during plains formation. Improved image and topographic data are required to measure stratigraphic and morphometric relationships and resolve this issue. Plains units are also home to an abundant and diverse set of volcanic features including steep-sided domes, shield fields, isolated volcanoes, collapse features and lava channels, some of which extend for 1000s of kilometers. The inferred viscosity range of plains-forming lavas, therefore, is immense, ranging from the extremely fluid flows (i.e., channel formers), to viscous, possibly felsic lavas of steep-sided domes. Wrinkle ridges deform many plains units and this has been taken to indicate that these ridges essentially form an early stratigraphic marker that limits subsequent volcanism to a minimum. However, subtle backscatter variations within many ridged plains units suggest (but do not prove) that some plains volcanism continued well after local ridge deformation ended. Furthermore, many of volcanic sources show little, if any, indications of tectonic modification and detailed analyses have concluded that resurfacing rates could be similar to those on Earth. Improving constraints on the rates and styles of volcanism within the plains could lend valuable insights into the evolution of Venus's internal heat budget and the transition from thin-lid to thick-lid tectonic regimes. Improved spatial and radiometric resolution of radar images would greatly improve abilities to construct the complex local stratigraphy of ridged plains. Constraining the resurfacing history of Venus is central to understanding how Earth-sized planets evolve and whether or not their evolutionary pathways lead to habitability. This goal can only be adequately addressed if broad coverage is added to the implementation strategies of any future mapping missions to Venus.

  14. Variability of the Venus condensational clouds from analysis of VIRTIS-M-IR observations of the near-infrared spectral windows

    NASA Astrophysics Data System (ADS)

    McGouldrick, Kevin; Tsang, Constantine C. C.

    2015-11-01

    The Medium Resolution, Infrared wavelength channel of the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS-M-IR) on the Venus Express spacecraft observed the atmosphere and surface of Venus for 921 orbits following orbit insertion in April 2006 until the failure of the cooling unit in October 2008. The clouds of Venus were long thought to be a uniform sort of perpetual stratocumulus, but near infrared observations by fly-by spacecraft such as Galileo (Near Infrared Mapping Spectrometer) and Cassini (Visible and Infrared Mapping Spectrometer), as well as ground-based observations, indicated a great deal of temporal and spatial inhomogeneity. The nearly three-year lifetime of the VIRTIS-M-IR instrument on Venus Express presents an unprecedented opportunity to quantify these spatial and temporal variations of the Venus clouds. Here, we present the results of an initial quantification of the overall tendencies of the Venus clouds, as measured by variations in the near infrared spectral windows located between wavelengths of 1.0 µm and 2.6 µm. In a companion submission, we also investigate the variations of carbon monoxide and other trace species quantifiable in these data (Tsang and McGouldrick 2015). This work is supported by the Planetary Mission Data Analysis Program, Grant Number NNX14AP94G.

  15. Solar Powered Flight on Venus

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony; Landis, Geoff (Technical Monitor)

    2004-01-01

    Solar powered flight within the Venus environment from the surface to the upper atmosphere was evaluated. The objective was to see if a station-keeping mission was possible within this environment based on a solar power generating system. Due to the slow rotation rate of Venus it would be possible to remain within the day light side of the planet for extended periods of time. However the high wind speeds and thick cloud cover make a station-keeping solar powered mission challenging. The environment of Venus was modeled as a function of altitude from the surface. This modeling included density, temperature, solar attenuation and wind speed. Using this environmental model flight with both airships and aircraft was considered to evaluate whether a station-keeping mission is feasible. The solar power system and flight characteristics of both types of vehicles was modeled and power balance was set up to determine if the power available from the solar array was sufficient to provide enough thrust to maintain station over a fixed ground location.

  16. High Temperature, Wireless Seismometer Sensor for Venus

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Meredith, Roger D.; Beheim, Glenn M.; Hunter Gary W.; Kiefer, Walter S.

    2012-01-01

    Space agency mission plans state the need to measure the seismic activity on Venus. Because of the high temperature on Venus (462? C average surface temperature) and the difficulty in placing and wiring multiple sensors using robots, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents the description and proof of concept measurements of a high temperature, wireless seismometer sensor for Venus. A variation in inductance of a coil caused by the movement of an aluminum probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 700 Hz in the transmitted signal from the oscillator/sensor system at 426? C. This result indicates that the concept may be used on Venus.

  17. High Altitude Venus Operations Concept Trajectory Design, Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Lugo, Rafael A.; Ozoroski, Thomas A.; Van Norman, John W.; Arney, Dale C.; Dec, John A.; Jones, Christopher A.; Zumwalt, Carlie H.

    2015-01-01

    A trajectory design and analysis that describes aerocapture, entry, descent, and inflation of manned and unmanned High Altitude Venus Operation Concept (HAVOC) lighter-than-air missions is presented. Mission motivation, concept of operations, and notional entry vehicle designs are presented. The initial trajectory design space is analyzed and discussed before investigating specific trajectories that are deemed representative of a feasible Venus mission. Under the project assumptions, while the high-mass crewed mission will require further research into aerodynamic decelerator technology, it was determined that the unmanned robotic mission is feasible using current technology.

  18. Hinode Views the 2012 Venus Transit - Duration: 4 seconds.

    NASA Video Gallery

    On June 5, 2012, Hinode captured these stunning views of the transit of Venus -- the last instance of this rare phenomenon until 2117. Hinode is a joint JAXA/NASA mission to study the connections o...

  19. Hinode Views the Transit of Venus - Duration: 48 seconds.

    NASA Video Gallery

    On June 5, 2012, Hinode captured this stunning view of the transit of Venus -- the last instance of this rare phenomenon until 2117. Hinode is a joint JAXA/NASA mission to study the connections of ...

  20. Planetary geometry handbook: Venus positional data, 1988 - 2020, volume 2

    NASA Technical Reports Server (NTRS)

    Sergeyevsky, A. B.; Snyder, G. C.; Paulson, B. L.; Cunniff, R. A.

    1983-01-01

    Graphical data necessary for the analysis of planetary exploration missions to Venus are presented. Positional and geometric information spanning the time period from 1988 through 2020 is provided. The data and the usage are explained.

  1. Hinode Views the 2012 Venus Transit - Duration: 8 seconds.

    NASA Video Gallery

    On June 5, 2012, Hinode captured these stunning views of the transit of Venus -- the last instance of this rare phenomenon until 2117. Hinode is a joint JAXA/NASA mission to study the connections o...

  2. THE ANALYZER OF SPACE PLASMAS AND ENERGETIC ATOMS (ASPERA-3) FOR THE MARS EXPRESS MISSION

    E-print Network

    California at Berkeley, University of

    THE ANALYZER OF SPACE PLASMAS AND ENERGETIC ATOMS (ASPERA-3) FOR THE MARS EXPRESS MISSION S interaction and to characterize the plasma and neutral gas environment within the space near Mars through. The Neutral Particle Imager (NPI) provides measurements of the integral ENA flux (0.1­60 keV) with no mass

  3. A sporadic layer in the Venus lower ionosphere of meteoric origin M. Patzold,1

    E-print Network

    Mendillo, Michael

    A sporadic layer in the Venus lower ionosphere of meteoric origin M. Pa¨tzold,1 S. Tellmann,1 B. Ha October 2008; accepted 29 October 2008; published 12 March 2009. [1] The Venus Express Radio Science (VeRa) experiment aboard Venus Express has detected, by means of radio occultation, distinct, low-lying layers

  4. VENUS CLOUD TOPS VIEWED BY HUBBLE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This is a NASA Hubble Space Telescope ultraviolet-light image of the planet Venus, taken on January 24 1995, when Venus was at a distance of 70.6 million miles (113.6 million kilometers) from Earth. Venus is covered with clouds made of sulfuric acid, rather than the water-vapor clouds found on Earth. These clouds permanently shroud Venus' volcanic surface, which has been radar mapped by spacecraft and from Earth-based telescope. At ultraviolet wavelengths cloud patterns become distinctive. In particular, a horizontal 'Y'-shaped cloud feature is visible near the equator. Similar features were seen from Mariner 10, Pioneer Venus, and Galileo spacecrafts. This global feature might indicate atmospheric waves, analogous to high and low pressure cells on Earth. Bright clouds toward Venus' poles appear to follow latitude lines. The polar regions are bright, possibly showing a haze of small particles overlying the main clouds. The dark regions show the location of enhanced sulfur dioxide near the cloud tops. From previous missions, astronomers know that such features travel east to west along with the Venus' prevailing winds, to make a complete circuit around the planet in four days. Because Venus is closer to the Sun than Earth, the planet appears to go through phases, like the Moon. When Venus swings close to Earth the planet's disk appears to grow in size, but changes from a full disk to a crescent. The image was taken with the Wide Field Planetary Camera-2, in PC mode. False color has been used enhance cloud features. Credit: L. Esposito (University of Colorado, Boulder), and NASA

  5. Zephyr: A Landsailing Rover for Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Oleson, Steven R.; Grantier, David

    2014-01-01

    With an average temperature of 450C and a corrosive atmosphere at a pressure of 90 bars, the surface of Venus is the most hostile environment of any planetary surface in the solar system. Exploring the surface of Venus would be an exciting goal, since Venus is a planet with significant scientific mysteries, and interesting geology and geophysics. Technology to operate at the environmental conditions of Venus is under development. A rover on the surface of Venus with capability comparable to the rovers that have been sent to Mars would push the limits of technology in high-temperature electronics, robotics, and robust systems. Such a rover would require the ability to traverse the landscape on extremely low power levels. We have analyzed an innovative concept for a planetary rover: a sail-propelled rover to explore the surface of Venus. Such a rover can be implemented with only two moving parts; the sail, and the steering. Although the surface wind speeds are low (under 1 m/s), at Venus atmospheric density even low wind speeds develop significant force. Under funding by the NASA Innovative Advanced Concepts office, a conceptual design for such a rover has been done. Total landed mass of the system is 265 kg, somewhat less than that of the MER rovers, with a 12 square meter rigid sail. The rover folds into a 3.6 meter aeroshell for entry into the Venus atmosphere and subsequent parachute landing on the surface. Conceptual designs for a set of hightemperature scientific instruments and a UHF communication system were done. The mission design lifetime is 50 days, allowing operation during the sunlit portion of one Venus day. Although some technology development is needed to bring the high-temperature electronics to operational readiness, the study showed that such a mobility approach is feasible, and no major difficulties are seen.

  6. X-Band Microwave Radiometry as a Tool for Understanding the Deep Atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Steffes, P. G.; Devaraj, K.; Butler, B. J.

    2013-12-01

    Understanding the composition, structure, and spatial variability of the deep Venus atmosphere, including the boundary layer, is a key future direction identified in the Decadal Review. While only Mariner 2 carried a microwave radiometer for the expressed purpose of evaluating the Venus atmosphere, subsequent missions to Venus and other planets have used radar receivers in a "passive mode" to map the microwave emission from both surfaces and atmospheres. Additionally, successful mapping of microwave emissions from the atmospheres of Venus and the outer planets using earth-based antenna arrays have given unique insights into the composition and variability of such atmospheres. In the past two decades, multiple observations of Venus have been made at X band (3.6 cm) using the Jansky Very Large Array (VLA), and maps have been created of the 3.6 cm emission from Venus. Since the emission morphology is related both to surface features and to the deep atmospheric absorption from CO2 and SO2 (see, e.g., Butler et al., Icarus 154, 2001), emission measurements can be used to give unique information regarding the deep atmosphere, once surface effects are removed. Since surface emissivities measured at the 12.6 cm wavelength by the Magellan mission can be extrapolated to 3.6 cm (see, e.g., Tryka and Muhleman, JGR(Planets) 197, 1992), the residual effects due to deep atmospheric variability can potentially be detected, as they were for higher altitudes at shorter wavelengths (1.3 cm and 2.0 cm, Jenkins et.al., Icarus 158, 2002). As results from this study show, the limited resolution and sensitivity of earth-based measurements make detection of moderate atmospheric variability somewhat difficult. However, the higher sensitivity and resolution provided by an orbiting X-Band radiometer can provide important insights into the variability and structure of the Venus boundary layer. As shown in the figure, the vertical resolution of X-Band radiometry compares well with IR sounding of the deep atmosphere of Venus.

  7. High Temperature Mechanisms for Venus Exploration

    NASA Astrophysics Data System (ADS)

    Ji, Jerri; Narine, Roop; Kumar, Nishant; Singh, Sase; Gorevan, Steven

    Future Venus missions, including New Frontiers Venus In-Situ Explorer and three Flagship Missions - Venus Geophysical Network, Venus Mobile Explorer and Venus Surface Sample Return all focus on searching for evidence of past climate change both on the surface and in the atmospheric composition as well as in the interior dynamics of the planet. In order to achieve these goals and objectives, many key technologies need to be developed for the Venus extreme environment. These key technologies include sample acquisition systems and other high-temperature mechanisms and mobility systems capable of extended operation when directly exposed to the Venus surface or lower atmosphere environment. Honeybee Robotics has developed two types of high temperature motors, the materials and components in both motors were selected based on the requirement to survive temperatures above a minimum of 460° C, at earth atmosphere. The prototype Switched Reluctance Motor (SRM) has been operated non-continuously for over 20 hours at Venus-like conditions (460° C temperature, mostly CO2 gas environment) and it remains functional. A drilling system, actuated by two SRMs was tested in Venus-like conditions, 460° C temperature and mostly CO2 gas environment, for more than 15 hours. The drill successfully completed three tests by drilling into chalk up to 6 inches deep in each test. A first generation Brushless DC (BLDC) Motor and high temperature resolver were also tested and the feasibility of the designs was demonstrated by the extended operation of both devices under Venus-like condition. Further development of the BLDC motor and resolver continues and these devices will, ultimately, be integrated into the development of a high temperature sample acquisition scoop and high temperature joint (awarded SBIR Phase II in October, 2007). Both the SR and BLDC motors will undergo extensive testing at Venus temperature and pressure (TRL6) and are expected to be mission ready before the next New Frontiers AO release. Scalable high temperature motor, resolver and bearing developments allow for creation of long lasting sample acquisition systems, booms, robot arms and even mobility systems that operate outside of an environment-controlled landed platform on the surface of Venus. The SR and BLDC motors are no longer expected to limit the life of Venus surface operations. With the accompanying high temperature bearing and other mechanisms development, surface operations will be limited only by available power. Therefore, the motor and resolver's capability to survive for hours (and potentially longer) in the environment is a major benefit to future Venus science missions and they also allow time for communication ground loops to optimize sample target selection and the possibility for acquiring multiple samples from the surface. The extreme temperature motors, resolver and other high temperature mechanisms therefore revolutionize the exploration of Venus.

  8. Venus Aerobot Surface Science Imaging System (VASSIS)

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    1999-01-01

    The VASSIS task was to design and develop an imaging system and container for operation above the surface of Venus in preparation for a Discovery-class mission involving a Venus aerobot balloon. The technical goals of the effort were to: a) evaluate the possible nadir-viewed surface image quality as a function of wavelength and altitude in the Venus lower atmosphere, b) design a pressure vessel to contain the imager and supporting electronics that will meet the environmental requirements of the VASSIS mission, c) design and build a prototype imaging system including an Active-Pixel Sensor camera head and VASSIS-like optics that will meet the science requirements. The VASSIS science team developed a set of science requirements for the imaging system upon which the development work of this task was based.

  9. Student directions First, let's compare the spectra of Venus and Earth. The spectrum of Venus was taken from

    E-print Network

    Mojzsis, Stephen J.

    for the mass of Mars' atmosphere using `me.' b. Write an expression for the amount of Carbon Dioxide in Mars% of the total mass of Venus' atmosphere is Carbon Dioxide, but only 0.04% of the total mass of Earth's atmosphere using `me' for the mass of Earth's atmosphere. b. Write an expression for the mass of Venus

  10. Systems design study of the Pioneer Venus spacecraft. Volume 3. Specifications

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Pioneer Venus spacecraft performance requirements are presented. The specifications include: (1) Design criteria and performance requirements for the Pioneer Venus spacecraft systems and subsystems for a 1978 multiprobe mission and a 1978 orbiter mission, spacecraft system interface, and scientific instrument integration.

  11. Carbon monoxide short term variability observed on Venus with SOIR/VEX

    NASA Astrophysics Data System (ADS)

    Vandaele, A. C.; Mahieux, A.; Robert, S.; Drummond, R.; Wilquet, V.; Bertaux, J. L.

    2015-08-01

    The SOIR instrument on board the ESA Venus Express mission has been operational since the insertion of the satellite around Venus in 2006. Since then, it has delivered high quality spectra of the atmosphere of Venus. Spectra are recorded in the IR spectral region (2.2-4.3 ?m) using the solar occultation geometry and give access to a vast number of ro-vibrational lines and bands of several key species of the atmosphere of Venus. Here we present the retrieval strategy applied to obtain high quality vertical profiles of carbon monoxide (CO) densities and volume mixing ratios (vmr), spanning the 65-150 km altitude range. We discuss the methodology used to derive the profiles and the validation process implemented to ensure the quality and reproducibility of the results. Influence of ancillary data, such as temperature, is discussed. High variability of CO densities and vmr is observed in relatively short term periods. Correlation between CO and CO2 densities, as well as between CO and temperature above 110 km, corroborates that the major process at those altitudes is the photodissociation of CO2 into CO.

  12. Mesospheric vertical thermal structure and winds on Venus from HHSMT CO spectral-line observations

    E-print Network

    Rengel, M; Jarchow, C

    2008-01-01

    We report vertical thermal structure and wind velocities in the Venusian mesosphere retrieved from carbon monoxide (12CO J=2-1 and 13CO J=2-1) spectral line observations obtained with the Heinrich Hertz Submillimeter Telescope (HHSMT). We observed the mesosphere of Venus from two days after the second Messenger flyby of Venus (on June 5 2007 at 23:10 UTC) during five days. Day-to-day and day-to-night temperature variations and short-term fluctuations of the mesospheric zonal flow were evident in our data. The extensive layer of warm air detected recently by SPICAV at 90 - to 100 km altitude is also detected in the temperature profiles reported here. These data were part of a coordinated ground-based Venus observational campaign in support of the ESA Venus Express mission. Furthermore, this study attempts to cross-calibrate space- and ground-based observations, to constrain radiative transfer and retrieval algorithms for planetary atmospheres, and to contribute to a more thorough understanding of the global pa...

  13. Mesospheric vertical thermal structure and winds on Venus from HHSMT CO spectral-line observations

    E-print Network

    M. Rengel; P. Hartogh; C. Jarchow

    2008-09-16

    We report vertical thermal structure and wind velocities in the Venusian mesosphere retrieved from carbon monoxide (12CO J=2-1 and 13CO J=2-1) spectral line observations obtained with the Heinrich Hertz Submillimeter Telescope (HHSMT). We observed the mesosphere of Venus from two days after the second Messenger flyby of Venus (on June 5 2007 at 23:10 UTC) during five days. Day-to-day and day-to-night temperature variations and short-term fluctuations of the mesospheric zonal flow were evident in our data. The extensive layer of warm air detected recently by SPICAV at 90 - to 100 km altitude is also detected in the temperature profiles reported here. These data were part of a coordinated ground-based Venus observational campaign in support of the ESA Venus Express mission. Furthermore, this study attempts to cross-calibrate space- and ground-based observations, to constrain radiative transfer and retrieval algorithms for planetary atmospheres, and to contribute to a more thorough understanding of the global patterns of circulation of the Venusian atmosphere.

  14. Interplanetary coronal mass ejection influence on high energy pick-up ions at Venus

    E-print Network

    California at Berkeley, University of

    Interplanetary coronal mass ejection influence on high energy pick-up ions at Venus T.R. McEnulty a Available online 10 August 2010 Keywords: Venus Ion escape Space weather ICME a b s t r a c t We have used the ion mass analyzer (IMA) and magnetometer (MAG) on Venus Express (VEX) to study escaping O+ during

  15. Planetary and Space Science 56 (2008) 802806 Ionospheric photoelectrons at Venus: Initial observations by

    E-print Network

    California at Berkeley, University of

    2008-01-01

    Planetary and Space Science 56 (2008) 802­806 Ionospheric photoelectrons at Venus: Initial in the Venus atmosphere by solar helium 30.4 nm photons. The detection was by the Analyzer of Space Plasma and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) on the Venus Express (VEx) European Space Agency (ESA

  16. Roadmap for Venus Exploration Roadmap for Venus Exploration

    E-print Network

    Rathbun, Julie A.

    Roadmap for Venus Exploration May 2014 #12;ii Roadmap for Venus Exploration At the VEXAG meeting in November 2013, it was resolved to update the scientific priorities and strategies for Venus exploration. To achieve this goal

  17. System design of the Pioneer Venus spacecraft. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Dorfman, S. D.

    1973-01-01

    The NASA Ames Research Center Pioneer Venus Project objective is to conduct scientific investigations of the planet Venus using spin stabilized spacecraft. The defined approach to accomplish this goal is to implement a multiprobe spacecraft mission and an orbiter spacecraft mission. Candidate launch vehicles for the Pioneer Venus missions were the Thor/Delta and Atlas/Centaur. The multiprobe spacecraft consists of a probe bus, one large probe, and three small probes. The probes are designed to survive to the surface of Venus, and to make in situ measurements of the Venusian atmosphere; the probe bus enters the atmosphere and makes scientific measurements until it burns out. The orbiter mission uses a spacecraft designed to orbit Venus for 225 days with an orbit period of about 24 hours (h). The probe bus and orbiter designs are to use a common spacecraft bus.

  18. Stirling Cooler Designed for Venus Exploration

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Mellott, Kenneth D.

    2004-01-01

    Venus having an average surface temperature of 460 degrees Celsius (about 860 degrees Fahrenheit) and an atmosphere 150 times denser than the Earth's atmosphere, designing a robot to merely survive on the surface to do planetary exploration is an extremely difficult task. This temperature is hundreds of degrees higher than the maximum operating temperature of currently existing microcontrollers, electronic devices, and circuit boards. To meet the challenge of Venus exploration, researchers at the NASA Glenn Research Center studied methods to keep a pressurized electronics package cooled, so that the operating temperature within the electronics enclosure would be cool enough for electronics to run, to allow a mission to operate on the surface of Venus for extended periods.

  19. Venus in Violet and Near Infrared Light

    NASA Technical Reports Server (NTRS)

    1990-01-01

    These images of the Venus clouds were taken by Galileo's Solid State Imaging System February 13,1990, at a range of about 1 million miles. The smallest detail visible is about 20 miles. The two right images show Venus in violet light, the top one at a time six hours later than the bottom one. They show the state of the clouds near the top of Venus's cloud deck. A right to left motion of the cloud features is evident and is consistent with westward winds of about 230 mph. The two left images show Venus in near infrared light, at the same times as the two right images. Sunlight penetrates through the clouds more deeply at the near infrared wavelengths, allowing a view near the bottom of the cloud deck. The westward motion of the clouds is slower (about 150 mph) at the lower altitude. The clouds are composed of sulfuric acid droplets and occupy a range of altitudes from 30 to 45 miles. The images have been spatially filtered to bring out small scale details and de-emphasize global shading. The filtering has introduced artifacts (wiggly lines running north/south) that are faintly visible in the infrared image. The Galileo Project is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory; its mission is to study Jupiter and its satellites and magnetosphere after multiple gravity assist flybys at Venus and Earth.

  20. Venus: Geochemical conclusions from the Magellan data

    NASA Technical Reports Server (NTRS)

    Wood, J. A.

    1992-01-01

    Though the Magellan mission was not designed to collect geochemical or petrological information, it has done so nonetheless. Since the time of the Pioneer Venus mission it has been known that high-altitude (greater than 2.5-5 km) mountainous areas on Venus exhibit anomalously low radiothermal emissivity (e less than 0.6). Magellan has greatly refined and extended these observations. The low emissivity requires surface material in the uplands to have a mineralogical composition that gives it a high bulk dielectric constant, greater than 20. The dielectric constant of dry terrestrial volcanic rocks seldom exceeds 7. The high-dielectric character of high-altitude surface material cannot be a primary property of the local volcanic rock, because there is no reason why rock having the required special mineralogy would erupt only at high altitudes. Therefore it is a secondary property; the primary Venus rock has reacted with the atmosphere to form a mineralogically different surface layer, and the secondary minerals formed are controlled by the ambient temperature, which decreases with altitude on Venus. A further investigation of venusian mineralogy is presented.

  1. Variability and local distribution of oxygen airglow on Venus

    NASA Astrophysics Data System (ADS)

    Migliorini, Alessandra; Zasova, Ludmila; Piccioni, Giuseppe; Drossart, Pierre; Cardesín Moinelo, Alejandro

    Venus-Express mission is orbiting Venus since June 2006, and VIRTIS, the spectro-imager on board the spacecraft is providing a large valuable dataset of oxygen airglow. In this work, we analyze the oxygen airglow in limb and nadir geometry, covering the period from June 2006 to December 2007. The study is aimed to point out horizontal and vertical local distribution of the oxygen emission and related variations during the considered observing period. As commonly already known, the airglow emission varies rapidly from day to day and in a long term average, it depicts an almost ideal picture of the global circulation from sub-solar to anti-solar point, with a maximum in emission at midnight. However, the oxygen airglow at short time scale seems to be strongly driven by local temporary dynamics within the same day, whose effects are observed on local variations of intensity and vertical peak height. Airglow intensity can vary of a factor from 2 to 10, by moving towards higher latitudes; peak emission is observed in average at about 98 km height, although sometimes it can be set at a different altitude with a more complex structure, for the same reason. Finally, the high spatial resolution of the VIRTIS instrument allows us to identify very fine structures in nadir geometry and provides a unique view in limb geometry, able to give a direct measurement of the airglow vertical profile. The oxygen airglow study significantly contributes to build up a more global picture of the dynamics in the upper atmosphere of Venus.

  2. Venus on the Verge

    NASA Astrophysics Data System (ADS)

    Zahnle, K. J.; Abe, Y.; Abe-Ouchi, A.; Sleep, N. H.

    2012-06-01

    Venus’s descent into hellish heat must have been caused by its proximity to the Sun. The story of how Venus lost its water becomes: too much sunlight caused a runaway greenhouse effect, any water evaporated, and the hydrogen escaped into space.

  3. HIGH-RESOLUTION SATELLITE IMAGING OF THE 2004 TRANSIT OF VENUS AND ASYMMETRIES IN THE CYTHEREAN ATMOSPHERE

    SciTech Connect

    Pasachoff, Jay M.; Schneider, Glenn; Widemann, Thomas

    2011-04-15

    This paper presents the only space-borne optical-imaging observations of the 2004 June 8 transit of Venus, the first such transit visible from Earth since AD 1882. The high-resolution, high-cadence satellite images we arranged from NASA's Transition Region and Coronal Explorer (TRACE) reveal the onset of visibility of Venus's atmosphere and give further information about the black-drop effect, whose causes we previously demonstrated from TRACE observations of a transit of Mercury. The atmosphere is gradually revealed before second contact and after third contact, resulting from the changing depth of atmospheric layers refracting the photospheric surface into the observer's direction. We use Venus Express observations to relate the atmospheric arcs seen during the transit to the atmospheric structure of Venus. Finally, we relate the transit images to current and future exoplanet observations, providing a sort of ground truth showing an analog in our solar system to effects observable only with light curves in other solar systems with the Kepler and CoRoT missions and ground-based exoplanet-transit observations.

  4. Mesospheric circulation at the cloud top level of Venus according to Venus Monitoring Camera images

    NASA Astrophysics Data System (ADS)

    Khatuntsev, Igor; Patsaeva, Marina; Ignatiev, Nikolay; Titov, Dmitri; Markiewicz, Wojciech; Turin, Alexander

    We present results of wind speed measurements at the cloud top level of Venus derived from manual cloud tracking in the UV (365 nm) and IR (965 nm) channels of the Venus Monitoring Camera Experiment (VMC) [1] on board the Venus Express mission. Cloud details have a maximal contrast in the UV range. More then 90 orbits have been processed. 30000 manual vectors were obtained. The period of the observations covers more than 4 venusian year. Zonal wind speed demonstrates the local solar time dependence. Possible diurnal and semidiurnal components are observed [2]. According to averaged latitude profile of winds at level of the upper clouds: -The zonal speed is slightly increasing by absolute values from 90 on the equator to 105 m/s at latitudes —47 degrees; -The period of zonal rotation has the maximum at the equator (5 earth days). It has the minimum (3 days) at altitudes —50 degrees. After minimum periods are slightly increasing toward the South pole; -The meridional speed has a value 0 on the equator, and then it is linear increasing up to 10 m/s (by absolute value) at 50 degrees latitude. "-" denotes movement from the equator to the pole. -From 50 to 80 degrees the meridional speed is again decreasing by absolute value up to 0. IR (965+10 nm) day side images can be used for wind tracking. The obtained speed of the zonal wind in the low and middle latitudes are systematically less than the wind speed derived from the UV images. The average zonal speed obtained from IR day side images in the low and average latitudes is about 65-70 m/s. The given fact can be interpreted as observation of deeper layers of mesosphere in the IR range in comparison with UV. References [1] Markiewicz W. J. et al. (2007) Planet. Space Set V55(12). P.1701-1711. [2] Moissl R., et al. (2008) J. Geophys. Res. 2008. doi:10.1029/2008JE003117. V.113.

  5. Atmospheric winds on the cloud top level of Venus according to Venus Monitoring Camera images

    NASA Astrophysics Data System (ADS)

    Khatuntsev, Igor; Ignatiev, Nikolai; Patsaeva, Marina; Titov, Dmitri; Markiewicz, Wojciech

    2010-05-01

    We present results of wind speed measurements at the cloud top level of Venus derived from manual and automated cloud tracking in the UV (365 nm) and IR (965 nm) channels of the Venus Monitoring Camera Experiment (VMC) [1] on board the Venus Express mission. Cloud details have a maximal contrast in the UV range. More then 80 orbits have been processed. More then 27500 manual vectors were obtained. The period of the observations covers more than 4 venusian year. Zonal wind speed demonstrates the local solar time dependence. Possible diurnal and semidiurnal components are observed [2]. According to averaged latitude profile of winds at level of the upper clouds: - The zonal speed is slightly increasing by absolute values from 90 on the equator to 105 m/s at latitudes —47 degrees; - The period of zonal rotation has the maximum at the equator (˜5 earth days). It has the minimum (˜3 days) at altitudes —50 degrees. After minimum periods are slightly increasing toward the South pole; - The meridional speed has a value ˜0 on the equator, and then it is linear increasing up to ˜ 10 m/s (by absolute value) at 50 degrees latitude. "-" denotes movement from the equator to the pole. From 50 to 80 degrees the meridional speed is again decreasing by absolute value up to 0. IR (965+10 nm) day side images can be used for wind tracking. The obtained speed of the zonal wind in the low and middle latitudes are systematically less than the wind speed derived from the UV images. The average zonal speed obtained from IR day side images in the low and average latitudes is about 65-70 m/s. The given fact can be interpreted as observation of deeper layers of mesosphere in the IR range in comparison with UV. References [1] Markiewicz W. J. et al. (2007) Planet. Space Set V55(12). P.1701-1711. [2] Moissl R., et al. (2008) J. Geophys. Res. 2008. doi:10.1029/2008JE003117. V.113.

  6. Venus Ionosphere and Solar Wind Interaction

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Luhmann, Janet G.; Ma, Yingjuan; Zhang, Tielong; Villarreal, M.

    Venus Express, which was inserted into orbit in mid-2006, has added significantly to the knowledge gained from Pioneer Venus from 1978 to 1992. This observational database interpreted in terms of modern multi-fluid codes and hybrid simulations has deepened our understanding of Earth’s very different twin sister planet. Furthermore, the very different orbits of VEX and PVO has allowed the more complete mapping of the volume of space around the planet. Now the bow shock has been probed over its full surface, the ionosphere mapped everywhere, and the tail studied from the ionosphere to 12 Venus radii. Some unexpected discoveries have been made. The exospheric hydrogen at Venus, unlike that at Mars, does not produce ion-cyclotron waves, perhaps because the stronger gravity of Venus produces a smaller geocorona. The solar wind interaction drapes the magnetic field around the planet, and a strong layer of magnetic field builds up at low altitudes. While the layer does not appear to penetrate into the dayside atmosphere (perhaps diffusing only slowly through the low atmosphere), it does appear to dip into the atmosphere at night. Surprisingly, over the poles, this layer is most strongly seen when the IMF BY component has a positive Y-component in Venus-Solar-Orbital coordinates. Multi-fluid simulations show that this result is consistent with the pressure of significant ion densities of ions with quite different mass which causes magnetic polarity control of the ion flow over the terminators. Reconnection is found in the tail close to the planet, and the structure of the outer tail found by PVO is confirmed to exist in the inner tail by VEX. When combined, the VEX and PVO Data provide a very comprehensive picture of the physics of the solar wind interaction with the ionosphere of Venus.

  7. On Target for Venus Set Oriented Computation of Energy Efficient Low Thrust Trajectories

    E-print Network

    and their stable and unstable manifolds ­ which are not present in two body problems ­ as candidate regions body problem as the underlying mathematical model. These techniques exploit the structure and geometry for a mission to Venus. Keywords: set oriented numerics, dynamical system, earth venus transfer, three body

  8. Improved Knowlegde of Venus Atmospheric Structure

    NASA Astrophysics Data System (ADS)

    Limaye, S. S.; Bougher, S.; Chamberlain, S.; Clancy, R. T.; Gilli, G.; Grassi, D.; Haus, R.; Herrmann, M.; Imamura, T.; Kohler, E.; Krause, P.; Lebonnois, S.; Mahieux, A.; Sandor, A.; Sornig, M.; Svedhem, H.; Tellmann, S.; Vandaele, A. C.; Widemann, T.; Wilson, C.; Mueller-Wodarg, I.; Zasova, L.

    2015-10-01

    Experiments onboard the European Space Agency's Venus Express orbiter has extended our knowledge about the vertical temperature and density structure above the clouds. The observations have been obtained by different techniques at different local times and latitudes and with different vertical and horizontal resolutions and coverage.

  9. Active volcanism on Venus in the Ganiki Chasma rift zone

    NASA Astrophysics Data System (ADS)

    Shalygin, E. V.; Markiewicz, W. J.; Basilevsky, A. T.; Titov, D. V.; Ignatiev, N. I.; Head, J. W.

    2015-06-01

    Venus is known to have been volcanically resurfaced in the last third of solar system history and to have undergone a significant decrease in volcanic activity a few hundred million years ago. However, fundamental questions remain: Is Venus still volcanically active today, and if so, where and in what geological and geodynamic environment? Here we show evidence from the Venus Express Venus Monitoring Camera for transient bright spots that are consistent with the extrusion of lava flows that locally cause significantly elevated surface temperatures. The very strong spatial correlation of the transient bright spots with the extremely young Ganiki Chasma, their similarity to locations of rift-associated volcanism on Earth, provide strong evidence for their volcanic origin and suggests that Venus is currently geodynamically active.

  10. System design of the Pioneer Venus spacecraft. Volume 2: Science

    NASA Technical Reports Server (NTRS)

    Acheson, L. K.

    1973-01-01

    The objectives of the low-cost Pioneer Venus space probe program are discussed. The space mission and science requirements are analyzed. The subjects considered are as follows: (1) the multiprobe mission, (2) the orbiter mission, (3) science payload accomodations, and (4) orbiter spacecraft experimental interface specifications. Tables of data are provided to show the science allocations for large and small probes. Illustrations of the systems and components of various probe configurations are included.

  11. The High Resolution Stereo Camera (HRSC) Experiment On The European Mars Express Mission

    NASA Astrophysics Data System (ADS)

    Neukum, G.; Hoffmann, H.; HRSC Science Experiment Team

    Imaging Mars is one of the main goals of the European Mars Express mission and will be performed by the German High Resolution Stereo Camera (HRSC). The HRSC ex- periment is a pushbroom scanning instrument with 9 CCD line detectors mounted in parallel on the focal plane. Its unique feature is the ability to obtain nearly simul- taneously imaging data of a specific site at high resolution, with along-track triple stereo, with four colours, and at five different phase angles, thus avoiding any time- dependent variations of the observation conditions. An additional Super-Resolution Channel (HRSC-SRC), a framing device, will yield nested-in images in the meter- range thus serving as the sharpening eye for detailed photogeologic studies. The spa- tial resolution from the nominal periapsis altitude of 250 km will be 10 m/pixel and 2.3 m/pixel for the HRSC-SRC. The manufacture of the flight hardware has been ac- complished. Before delivery of the flight model to ESA in January 2002, tests of the instrument were performed demonstrating its imaging capabilities and performances. During the nominal operational lifetime of the mission of 1 Martian year, it will be possible to cover at least 50% of the Martian surface at a spatial resolution of better than 15 m/pixel. More than 70% of the Martian surface can be observed at a spatial resolution of better than 30 m/pixel, while more than 1% of the surface will be im- aged at about 2.5 m/pixel. HRSC on Mars Express will be able to close the existing gap between medium to low-resolution coverage on the one hand and the very high resolution images of Mars Global Surveyor as well as the in-situ observations and measurements by landers on the other hand. The HRSC on Mars Express will make a major contribution to the study of Martian geosciences with special emphasis on the evolution of the Martian surface in general, the evolution of volcanism, and the role of water throughout the Martian history. The instrument will obtain images containing morphologic and topographic information at high spatial and vertical resolution al- lowing the improvement of the Martian cartographic base down to scales of 1:50,000. In order to optimize the science return, a thorough selection of primary target sites is actually performed by the international Co-Investigator team comprising 40 scien- tists from 10 countries. This experiment will also address atmospheric phenomena and atmosphere-surface interactions and will provide urgently needed support for ongoing and future lander missions as well as for exobiological studies.

  12. Salt tectonics on Venus

    SciTech Connect

    Wood, C.A.; Amsbury, D.

    1986-05-01

    The discovery of a surprisingly high deuterium/hydrogen ratio on Venus immediately led to the speculation that Venus may have once had a volume of surface water comparable to that of the terrestrial oceans. The authors propose that the evaporation of this putative ocean may have yielded residual salt deposits that formed various terrain features depicted in Venera 15 and 16 radar images. By analogy with models for the total evaporation of the terrestrial oceans, evaporite deposits on Venus should be at least tens to hundreds of meters thick. From photogeologic evidence and in-situ chemical analyses, it appears that the salt plains were later buried by lava flows. On Earth, salt diapirism leads to the formation of salt domes, anticlines, and elongated salt intrusions - features having dimensions of roughly 1 to 100 km. Due to the rapid erosion of salt by water, surface evaporite landforms are only common in dry regions such as the Zagros Mountains of Iran, where salt plugs and glaciers exist. Venus is far drier than Iran; extruded salt should be preserved, although the high surface temperature (470/sup 0/C) would probably stimulate rapid salt flow. Venus possesses a variety of circular landforms, tens to hundreds of kilometers wide, which could be either megasalt domes or salt intrusions colonizing impact craters. Additionally, arcurate bands seen in the Maxwell area of Venus could be salt intrusions formed in a region of tectonic stress. These large structures may not be salt features; nonetheless, salt features should exist on Venus.

  13. Venus Gravity Handbook

    NASA Technical Reports Server (NTRS)

    Konopliv, Alexander S.; Sjogren, William L.

    1996-01-01

    This report documents the Venus gravity methods and results to date (model MGNP90LSAAP). It is called a handbook in that it contains many useful plots (such as geometry and orbit behavior) that are useful in evaluating the tracking data. We discuss the models that are used in processing the Doppler data and the estimation method for determining the gravity field. With Pioneer Venus Orbiter and Magellan tracking data, the Venus gravity field was determined complete to degree and order 90 with the use of the JPL Cray T3D Supercomputer. The gravity field shows unprecedented high correlation with topography and resolution of features to the 2OOkm resolution. In the procedure for solving the gravity field, other information is gained as well, and, for example, we discuss results for the Venus ephemeris, Love number, pole orientation of Venus, and atmospheric densities. Of significance is the Love number solution which indicates a liquid core for Venus. The ephemeris of Venus is determined to an accuracy of 0.02 mm/s (tens of meters in position), and the rotation period to 243.0194 +/- 0.0002 days.

  14. Pioneer Venus Data Analysis

    NASA Technical Reports Server (NTRS)

    Jones, Douglas E.

    1996-01-01

    Analysis and interpretation of data from the Orbiter Retarding Potential Analyzer (ORPA) onboard the Pioneer Venus Orbiter is reported. By comparing ORPA data to proton data from the Orbiter Plasma Analyzer (OPA), it was found that the ORPA suprathermal electron densities taken outside the Venusian ionopause represent solar wind electron densities, thus allowing the high resolution study of Venus bow shocks using both magnetic field and solar wind electron data. A preliminary analysis of 366 bow shock penetrations was completed using the solar wind electron data as determined from ORPA suprathermal electron densities and temperatures, resulting in an estimate of the extent to which mass loading pickup of O+ (UV ionized O atoms flowing out of the Venus atmosphere) upstream of the Venus obstacle occurred. The pickup of O+ averaged 9.95%, ranging from 0.78% to 23.63%. Detailed results are reported in two attached theses: (1) Comparison of ORPA Suprathermal Electron and OPA Solar Wind Proton Data from the Pioneer Venus Orbiter and (2) Pioneer Venus Orbiter Retarding Potential Analyzer Observations of the Electron Component of the Solar Wind, and of the Venus Bow Shock and Magnetosheath.

  15. Sensor Amplifier for the Venus Ground Ambient

    NASA Technical Reports Server (NTRS)

    DelCastillo, Linda Y.; Johnson, Travis W.; Hatake, Toshiro; Mojarradi, Mohammad M.; Kolawa, Elizabeth A.

    2006-01-01

    Previous Venus Landers employed high temperature pressure vessels, with thermally protected electronics, to achieve successful missions, with a maximum surface lifetime of 127 minutes. Extending the operating range of electronic systems to the temperatures (480 C) and pressures (90 bar) of the Venus ground ambient would significantly increase the science return of future missions. Toward that end, the current work describes the innovative design of a sensor preamplifier, capable of working in the Venus ground ambient and designed using commercial components (thermionic vacuum tubes, wide band gap transistors, thick film resistors, advanced high temperature capacitors, and monometallic interfaces) To identify commercial components and electronic packaging materials that are capable of operation within the specified environment, a series of active devices, passive components, and packaging materials were screened for operability at 500C, assuming a 10x increase in the mission lifetime. In addition. component degradation as a function of time at 500(deg)C was evaluated. Based on the results of these preliminary evaluations, two amplifiers were developed.

  16. Explosive propulsion applications. [to future unmanned missions

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Varsi, G.; Back, L. H.

    1974-01-01

    The feasibility and application of an explosive propulsion concept capable of supporting future unmanned missions in the post-1980 era were examined and recommendations made for advanced technology development tasks. The Venus large lander mission was selected as the first in which the explosive propulsion concept can find application. A conceptual design was generated and its performance, weight, costs, and interaction effects determined. Comparisons were made with conventional propulsion alternatives. The feasibility of the explosive propulsion system was verified for planetology experiments within the dense atmosphere of Venus as well as the outer planets. Additionally, it was determined that the Venus large lander mission could be augmented ballistically with a significant delivery margin.

  17. Planetary and Space Science 56 (2008) 807811 First observation of energetic neutral atoms in the Venus environment

    E-print Network

    California at Berkeley, University of

    2008-01-01

    in the Venus environment A. Gallia,Ã, P. Wurza , P. Bochslera , S. Barabashb , A. Grigorievb , Y. Futaanab , M The ASPERA-4 instrument on board the Venus Express spacecraft offers for the first time the possibility to directly measure the emission of energetic neutral atoms (ENAs) in the vicinity of Venus. When

  18. The Venus ground-based image Active Archive: a database of amateur observations of Venus in ultraviolet and infrared light

    E-print Network

    Barentsen, Geert

    2013-01-01

    The Venus ground-based image Active Archive is an online database designed to collect ground-based images of Venus in such a way that they are optimally useful for science. The Archive was built to support ESA's Venus Amateur Observing Project, which utilises the capabilities of advanced amateur astronomers to collect filtered images of Venus in ultraviolet, visible and near-infrared light. These images complement the observations of the Venus Express spacecraft, which cannot continuously monitor the northern hemisphere of the planet due to its elliptical orbit with apocentre above the south pole. We present the first set of observations available in the Archive and assess the usability of the dataset for scientific purposes.

  19. Transits of Venus and Mercury as muses

    NASA Astrophysics Data System (ADS)

    Tobin, William

    2013-11-01

    Transits of Venus and Mercury have inspired artistic creation of all kinds. After having been the first to witness a Venusian transit, in 1639, Jeremiah Horrocks expressed his feelings in poetry. Production has subsequently widened to include songs, short stories, novels, novellas, sermons, theatre, film, engravings, paintings, photography, medals, sculpture, stained glass, cartoons, stamps, music, opera, flower arrangements, and food and drink. Transit creations are reviewed, with emphasis on the English- and French-speaking worlds. It is found that transits of Mercury inspire much less creation than those of Venus, despite being much more frequent, and arguably of no less astronomical significance. It is suggested that this is primarily due to the mythological associations of Venus with sex and love, which are more powerful and gripping than Mercury's mythological role as a messenger and protector of traders and thieves. The lesson for those presenting the night sky to the public is that sex sells.

  20. Temporal and Spatial Variations of Venus Cloud Properties

    NASA Astrophysics Data System (ADS)

    Hovenier, J. W.; Braak, C. J.; Knibbe, W. J. J.; de Haan, J. F.; Travis, L. D.

    1997-07-01

    Polarization observations made by the Pioneer Venus Orbiter early in its mission could not be explained solely by the micron sized particles deduced by Hansen and Hovenier [1974] from groundbased polarimetry. In addition to these particles, Kawabata et al. [1980] needed to assume the presence of smaller particles. These submicron sized particles are located above and within the main cloud deck. Using Pioneer Venus polarimetry data covering the entire mission, we analyzed the disk-averaged polarization to study temporal variations of the amount of submicron sized particles. We show that this amount decreased during the 1980's, while anomalous behavior occurred in 1983. The method used for this analysis is based on Newton-Raphson iteration and multiple scattering calculations. These calculations were performed using the adding/doubling method. We also present a method to conduct a similar analysis on a pixel-wise basis, in order to explore spatial variations of Venus' cloud properties. In this analysis, we pay attention to the relation between Venus' ultraviolet brightness variations and the amount og submicron sized particles. Preliminary results of this analysis are shown. References: Hansen, J. E., and J. W. Hovenier, "Interpretation of the polarization of Venus", J. Atmos. Sci. 31, 1137-1160, 1974 Kawabata, K., D. L. Coffeen, J. E. Hansen, W. A. Lane, M. Sato, and L. D. Travis, "Cloud and haze properties from Pioneer Venus polarimetry", J. Geophys. Res. 85, 8129-8140, 1980

  1. Geologic Map of the Meskhent Tessera Quadrangle (V-3), Venus

    USGS Publications Warehouse

    Ivanov, Mikhail A.; Head, James W., III

    2008-01-01

    The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphere on October 12, 1994. Magellan Mission objectives included (1) improving the knowledge of the geological processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving the knowledge of the geophysics of Venus by analysis of Venusian gravity. The Meskhent Tessera quadrangle is in the northern hemisphere of Venus and extends from lat 50 degrees to 75 degrees N. and from long 60 degrees to 120 degrees E. In regional context, the Meskhent Tessera quadrangle is surrounded by extensive tessera regions to the west (Fortuna and Laima Tesserae) and to the south (Tellus Tessera) and by a large basinlike lowland (Atalanta Planitia) on the east. The northern third of the quadrangle covers the easternmost portion of the large topographic province of Ishtar Terra (northwestern map area) and the more localized upland of Tethus Regio (northeastern map area).

  2. The thermal balance of the lower atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Tomasko, M. G.

    1981-01-01

    The temperature near the surface of Venus (now established at 730 K) is remarkably high in view of Venus's cloud cover which causes the planet to absorb even less sunlight than does Earth. Early attempts to understand the thermal balance that leads to this unusual state were hindered by the lack of basic information regarding the composition, temperature-pressure structure, cloud properties, and wind field of the lower atmosphere. A series of successful space missions have measured many of the above quantities that control the transfer of heat in Venus's lower atmosphere. The relevant observational data are summarized and the attempts to understand the thermal balance of Venus's atmosphere below the cloud tops are reviewed. The data indicate that sufficient sunlight penetrates to deep atmospheric levels and is trapped by the large thermal opacity of the atmosphere to essentially account for the high temperatures observed.

  3. Solar Flight on Mars and Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; LaMarre, Christopher; Colozza, Anthony

    2002-01-01

    Solar powered aircraft are of interest for exploring both Mars and Venus. The thin atmosphere of Mars presents a difficult environment for flying. It is clear that a new approach is needed. By making a totally solar airplane, we can eliminate many of the heavy components, and make an airplane that can fly without fuel. Using high efficiency solar cells, we can succeed with an airplane design that can fly for up to 6 hours in near-equatorial regions of Mars (4 hours of level flight, plus two hours of slow descent), and potentially fly for many days in the polar regions. By designing an airplane for a single day flight. In particular, this change means that we no longer have to cope with the weight of the energy storage system that made previous solar powered airplanes for Mars impractical). The new airplane concept is designed to fly only under the optimal conditions: near equatorial flight, at the subsolar point, near noon. We baseline an 8 kg airplane, with 2 kg margin. Science instruments will be selected with the primary criterion of low mass. Solar-powered aircraft are also quite interesting for the exploration of Venus. Venus provides several advantages for flying a solar-powered aircraft. At the top of the cloud level, the solar intensity is comparable to or greater than terrestrial solar intensities. The atmospheric pressure makes flight much easier than on planets such as Mars. The atmospheric pressure on Venus is presented. From an altitude of approximately 45 km (pressure = 2 bar), to approximately 60 km (pressure = 0.2 bar), terrestrial airplane experience can be easily applied to a Venus airplane design. At these flight altitudes, the temperature varies from 80 C at 45 km, decreasing to -35 C at 60 km. Also, the slow rotation of Venus allows an airplane to be designed for flight within continuous sunlight, eliminating the need for energy storage for nighttime flight. These factors make Venus a prime choice for a long-duration solar-powered aircraft. Fleets of solar-powered aircraft could provide an architecture for efficient and low-cost comprehensive coverage for a variety of scientific missions. Exploratory planetary mapping and atmospheric sampling can lead to a greater understanding of the greenhouse effect not only on Venus but on Earth as well.

  4. Solar Airplane Concept Developed for Venus Exploration

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2004-01-01

    An airplane is the ideal vehicle for gathering atmospheric data over a wide range of locations and altitudes, while having the freedom to maneuver to regions of scientific interest. Solar energy is available in abundance on Venus. Venus has an exoatmospheric solar flux of 2600 W/m2, compared with Earth's 1370 W/m2. The solar intensity is 20 to 50 percent of the exoatmospheric intensity at the bottom of the cloud layer, and it increases to nearly 95 percent of the exoatmospheric intensity at 65 km. At these altitudes, the temperature of the atmosphere is moderate, in the range of 0 to 100 degrees Celsius, depending on the altitude. A Venus exploration aircraft, sized to fit in a small aeroshell for a "Discovery" class scientific mission, has been designed and analyzed at the NASA Glenn Research Center. For an exploratory aircraft to remain continually illuminated by sunlight, it would have to be capable of sustained flight at or above the wind speed, about 95 m/sec at the cloud-top level. The analysis concluded that, at typical flight altitudes above the cloud layer (65 to 75 km above the surface), a small aircraft powered by solar energy could fly continuously in the atmosphere of Venus. At this altitude, the atmospheric pressure is similar to pressure at terrestrial flight altitudes.

  5. 10. The surface and interior of venus

    USGS Publications Warehouse

    Masursky, H.; Kaula, W.M.; McGill, G.E.; Pettengill, G.H.; Phillips, R.J.; Russell, C.T.; Schubert, G.; Shapiro, I.I.

    1977-01-01

    Present ideas about the surface and interior of Venus are based on data obtained from (1) Earth-based radio and radar: temperature, rotation, shape, and topography; (2) fly-by and orbiting spacecraft: gravity and magnetic fields; and (3) landers: winds, local structure, gamma radiation. Surface features, including large basins, crater-like depressions, and a linear valley, have been recognized from recent ground-based radar images. Pictures of the surface acquired by the USSR's Venera 9 and 10 show abundant boulders and apparent wind erosion. On the Pioneer Venus 1978 Orbiter mission, the radar mapper experiment will determine surface heights, dielectric constant values and small-scale slope values along the sub-orbital track between 50??S and 75??N. This experiment will also estimate the global shape and provide coarse radar images (40-80 km identification resolution) of part of the surface. Gravity data will be obtained by radio tracking. Maps combining radar altimetry with spacecraft and ground-based images will be made. A fluxgate magnetometer will measure the magnetic fields around Venus. The radar and gravity data will provide clues to the level of crustal differentiation and tectonic activity. The magnetometer will determine the field variations accurately. Data from the combined experiments may constrain the dynamo mechanism; if so, a deeper understanding of both Venus and Earth will be gained. ?? 1977 D. Reidel Publishing Company.

  6. Astrobiology and Venus exploration

    NASA Astrophysics Data System (ADS)

    Grinspoon, David H.; Bullock, Mark A.

    For hundreds of years prior to the space age, Venus was considered among the most likely homes for extraterrestrial life. Since planetary exploration began, Venus has not been considered a promising target for Astrobiological exploration. However, Venus should be central to such an exploration program for several reasons. At present Venus is the only other Earth-sized terrestrial planet that we know of, and certainly the only one we will have the opportunity to explore in the foreseeable future. Understanding the divergence of Earth and Venus is central to understanding the limits of habitability in the inner regions of habitable zones around solar-type stars. Thus Venus presents us with a unique opportunity for putting the bulk properties, evolution and ongoing geochemical processes of Earth in a wider context. Many geological and meteorological processes otherwise active only on Earth at present are currently active on Venus. Active volcanism most likely affects the climate and chemical equilibrium state of the atmosphere and surface, and maintains the global cloud cover. Further, if we think beyond the specifics of a particular chemical system required to build complexity and heredity, we can ask what general properties a planet must possess in order to be considered a possible candidate for life. The answers might include an atmosphere with signs of flagrant chemical disequilibrium and active, internally driven cycling of volatile elements between the surface, atmosphere and interior. At present, the two planets we know of which possess these characteristics are Earth and Venus. Venus almost surely once had warm, habitable oceans. The evaporation of these oceans, and subsequent escape of hydrogen, most likely resulted in an oxygenated atmosphere. The duration of this phase is poorly understood, but during this time the terrestrial planets were not isolated. Rather, due to frequent impact transport, they represented a continuous environment for early microbial life. Life, once established in the early oceans of Venus, may have migrated to the clouds which, on present day Venus, may represent a habitable niche. Though highly acidic, this aqueous environment enjoys moderate temperatures, surroundings far from chemical equilibrium, and potentially useful radiation fluxes. Observations of unusual chemistry in the clouds, and particle populations that are not well characterized, suggest that this environment must be explored much more fully before biology can be ruled out. A sulfur-based metabolism for cloud-based life on Venus has recently been proposed (Schulze-Makuch et al., 2004). While speculative, these arguments, along with the discovery of terrestrial extremophile organisms that point toward the plausibility of survival in the Venusian clouds, establish the credibility of astrobiological exploration of Venus. Arguments for the possible existence of life on Mars or Europa are, by convention and repetition, seen as more mainstream than arguments for life elsewhere, but their logical status is similar to plausibility arguments for life on Venus. With the launch of COROT in 2006 and Kepler in 2008 the demographics of Earth-sized planets in our galaxy should finally become known. Future plans for a Terrestrial Planet Finder or Darwin-type space-based spectrograph should provide the capability of studying the atmospheric composition and other properties of terrestrial planets. One of the prime rationales for building such instruments is the possibility of identifying habitable planets or providing more generalized observational constraints on the habitable zones of stellar systems. Given the prevalence of CO2 dominated atmospheres in our own solar system, it is quite likely that a large fraction of these will be Venus-like in composition and evolutionary history. We will be observing these planets at random times in their evolution. In analogy with our own solar system, it is just as likely that we will find representatives of early Venus and early Earth type planets from the first 2 billion years of their evolution as i

  7. The Atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Hansen, J. E. (editor)

    1975-01-01

    Topics considered at the conference included the dynamics, structure, chemistry, and evolution of the Venus atmosphere, as well as cloud physics and motion. Infrared, ultraviolet, and radio occultation methods of analysis are discussed, and atmospheric models are described.

  8. Plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1981-01-01

    The high surface temperature of Venus implies a permanently buoyant lithosphere and a thick basaltic crust. Terrestrial-style tectonics with deep subduction and crustal recycling is not possible. Overthickened basaltic crust partially melts instead of converting to eclogite. Because mantle magmas do not have convenient access to the surface the Ar-40 abundance in the atmosphere should be low. Venus may provide an analog to Archean tectonics on the earth.

  9. Pioneer Venus data analysis for the retarding potential analyzer

    NASA Technical Reports Server (NTRS)

    Knudsen, William C.

    1993-01-01

    This report describes the data analysis and archiving activities, analysis results, and instrument performance of the orbiter retarding potential analyzer (ORPA) flown on the Pioneer Venus Orbiter spacecraft during the period, Aug. 1, 1988 to Sept. 30, 1993. During this period, the periapsis altitude of the Orbiter spacecraft descended slowly from 1900 km altitude, at which altitude the spacecraft was outside the Venus ionosphere, to approximately 130 km altitude in Oct. 1992 at which time communication with the spacecraft ceased as a result of entry of the spacecraft into the Venus atmosphere. The quantity of ORPA data returned during this reporting period was greatly reduced over that recovered in the previous years of the mission because of the reduced power capability of the spacecraft, loss of half of the onboard data storage, and partial failure of the ORPA. Despite the reduction in available data, especially ionospheric data, important scientific discoveries resulted from this extended period of the Pioneer Venus mission. The most significant discovery was that of a strong solar cycle change in the size of the dayside ionosphere and the resulting shutoff of flow of dayside ions into the nightside hemisphere. The large, topside O+ F2 ionospheric layer observed during the first three years of the Pioneer Venus mission, a period of solar cycle maximum activity, is absent during the solar cycle minimum activity period.

  10. An analysis of AMTEC, multi-cell ground-demo for the Pluto/Express mission

    SciTech Connect

    Tournier, J.M.; El-Genk, M.S.

    1998-07-01

    Results of recent tests of an 8-cell, AMTEC ground-demo are analyzed and the performance of individual cells compared. The ground-demo produced a peak electric power of 27 W{sub e} at an output voltage of 16 V, when tested at hot and cold side temperatures of 1123 K and 553 K. The electric power output and terminal voltage of the individual cells, however, differed by as much as 25%, from 2.94 to 3.76 W{sub e}, and 1.73 to 2.21 V, respectively. These variations were attributed to differences in: (a) contact resistance between electrode / BASE / current collector; (b) current (or electrons) leakage between anode and cathode electrodes through the metal-ceramic braze joint between BASE tubes and support plate; and (c) the charge-exchange polarization losses. Model's predictions compared very well with measured voltage and electric power output of individual cells and of the ground-demo. At the operating conditions for the Pluto/Express spacecraft (T{sub hot} {approximately} 1200 K, T{sub cd} {approximately} 573 K), the best performing ground-demo cell would have delivered 5 W{sub e} at an output voltage of 3 V. These values, however, are still significantly lower than those needed to meet the Pluto/Express mission power requirements (8.2 W{sub e} at 3.5 V, per cell).

  11. Life on Venus

    NASA Astrophysics Data System (ADS)

    Cockell, Charles S.

    1999-12-01

    A fundamental question in exobiology remains the degree to which habitats on Venus, past and present, were, or are suitable for life. This has relevance for assessing the exobiological potential of extrasolar Venus-like greenhouse planets. In this paper the parameters of the Venusian surface and atmosphere are considered and the biochemical adaptations required to survive them are explored in the light of new information on microbial adaptations to extreme environments. Neither the pressure (9.5 MPa) nor the high carbon dioxide concentrations (97%) represent a critical constraint to the evolution of life on the surface or in the atmosphere. The most significant constraints to life on the surface are the lack of liquid water and the temperature (464°C). In the lower and middle cloud layers of Venus, temperatures drop and water availability increases, generating a more biologically favorable environment. However, acidity and the problem of osmoregulation in hygroscopic sulfuric acid clouds become extreme and probably life-limiting. If it is assumed that these constraints can be overcome, considerations on the survival of acidophilic sulfate-reducing chemoautotrophs suspended as aerosols in such an environment show that Venus does come close to possessing a habitable niche. Conditions on the surface and in the atmosphere may have been greatly ameliorated on early Venus and may also be ameliorated on extrasolar planets with early Venus-like characteristics where temperatures are less extreme and liquid water is available.

  12. 3. ALTOVITI VENUS STATUE IN THE TEMPLE OF VENUS AS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. ALTOVITI VENUS STATUE IN THE TEMPLE OF VENUS AS SEEN FROM LIVING ROOM DOORS, SOUTHEAST FACADE OF KYKUIT HOUSE, ON AXIS WITH LINDEN ALLEE - Kykuit, 200 Lake Road, Pocantico Hills, Westchester County, NY

  13. O+ ion flow below the magnetic barrier at Venus post terminator

    NASA Astrophysics Data System (ADS)

    Szego, K.; Bebesi, Z.; Dobe, Z.; Fränz, M.; Fedorov, A.; Barabash, S.; Coates, A. J.; Zhang, T. L.

    2009-01-01

    Venus forms an obstacle in the streaming solar wind; inside the obstacle boundary (that is below the magnetic barrier) the ions of planetary origin dominate the plasma. The objective of this study is to investigate the properties of the O+ ions inside the obstacle boundary of Venus in the wake; we are especially interested in the characterization of the different plasma regions the O+ ions occupy. The study is based on the data collected by the ASPERA 4 plasma analyzer flying onboard of the Venus Express mission in a region never explored before experimentally. The obstacle boundary was approximately identified from the dropout of magnetospheric electrons and the sharp decrease of the proton speed; the entry point correlated well with the location of the magnetic barrier derived by eyes from magnetometer data. The most characteristic structures seen during the various flybys were (1) the tailward continuation of the mantle was evident; (2) in the mantle near Venus the O+ ion flow was significantly intense in low-energy counts; (3) the inbound and outbound crossings of the tailward boundary were sharp, characterized by less intense but higher-energy O+ beams; (4) the crossing of the central tail region (current sheet) was marked by the change of the sign of Bx and by an intense low-energy O+ ion flux; (5) it is remarkable that the O+ ion outflow was not confined to the central tail region; the intensity elsewhere was highly variable, resulting in a ray-like outflow pattern in most of the cases.

  14. The evolution of Venus: Present state of knowledge and future exploration

    NASA Astrophysics Data System (ADS)

    Chassefière, Eric; Wieler, Rainer; Marty, Bernard; Leblanc, François

    2012-04-01

    A detailed characterization of the formation and evolution of Venus is a key link to the study of terrestrial planets, and to their divergent evolutions. While Earth and to a lesser extent Mars (thanks to the analysis of SNC meteorites) are extensively studied in a comparative planetology context, the history of the most Earth-like planet of the Solar System, Venus, is still poorly understood. For how long has Venus been in its current extreme climate state? When and how did it diverge from a (possible) early Earth-like state? Has Venus been a potentially habitable planet at some time of its early history? Did a "cool early Venus" stage occur between the end of accretion and the late heavy bombardment, like suspected for Earth? What are the implications of the Venus/Earth comparison for the nature and evolution of habitable terrestrial planets throughout the universe? A major observational missing link in our understanding of Venus' climate evolution is the elementary and isotopic pattern of noble gases and of stable isotopes in Venus' atmosphere, still poorly known. The concentrations of heavy noble gases (Kr, Xe) and their isotopes are mostly unknown, and our knowledge of light noble gases and stable isotopes is incomplete and inaccurate. In this paper, we summarize our present understanding of Venus' early evolution, including the crucial question of knowing if water ever condensed at the surface of the planet. Then, we assess the potential contribution of a precise measurement of noble gases, their isotopes and stable isotopes to improve of our understanding of Venus evolution, and list the main questions that noble gases and isotope measurements would help to answer. Finally, we show how future exploration of Venus could allow to gain a glimpse into the early evolution of Venus through a small in-situ mission based on a single balloon probe, called EVE (European Venus Explorer), proposed in the frame of the ESA Cosmic Vision program.

  15. Venus Mobile Explorer with RPS for Active Cooling: A Feasibility Study

    NASA Technical Reports Server (NTRS)

    Leifer, Stephanie D.; Green, Jacklyn R.; Balint, Tibor S.; Manvi, Ram

    2009-01-01

    We present our findings from a study to evaluate the feasibility of a radioisotope power system (RPS) combined with active cooling to enable a long-duration Venus surface mission. On-board power with active cooling technology featured prominently in both the National Research Council's Decadal Survey and in the 2006 NASA Solar System Exploration Roadmap as mission-enabling for the exploration of Venus. Power and cooling system options were reviewed and the most promising concepts modeled to develop an assessment tool for Venus mission planners considering a variety of future potential missions to Venus, including a Venus Mobile Explorer (either a balloon or rover concept), a long-lived Venus static lander, or a Venus Geophysical Network. The concepts modeled were based on the integration of General Purpose Heat Source (GPHS) modules with different types of Stirling cycle heat engines for power and cooling. Unlike prior investigations which reported on single point design concepts, this assessment tool allows the user to generate either a point design or parametric curves of approximate power and cooling system mass, power level, and number of GPHS modules needed for a "black box" payload housed in a spherical pressure vessel.

  16. Vena, Veda, Venus Subhash Kak

    E-print Network

    Koppelman, David M.

    Vena, Veda, Venus Subhash Kak Louisiana State University Baton Rouge, LA 70803-5901, USA Brahmavidy suggested that Vedic Vena is Venus but this identification has been disputed. In this article we provide of the planets in the third millennium B.C.E. Key Words: Venus, Ancient astronomy, Vena 1 Introduction The name

  17. Astrobiology and Venus Exploration

    NASA Astrophysics Data System (ADS)

    Grinspoon, D. H.; Bullock, M. A.

    2005-12-01

    Venus has not traditionally been considered a promising target for Astrobiological exploration. We propose that Venus should be central to such an exploration program for several reasons. 1) Putting Earth life in context: Venus is the only other Earth-sized terrestrial planet that we know of, and certainly the only one we will have the opportunity to explore in the foreseeable future. Many geological and meteorological processes otherwise active only on Earth at present are currently active on Venus. For example, active volcanism is most likely responsible for maintaining the global cloud cover (Bullock and Grinspoon, 2001). Understanding the divergence of Earth and Venus is central to understanding the limits of habitability in the inner regions of habitable zones around solar-type stars. Thus Venus presents us with a unique opportunity for putting the bulk properties, evolution and ongoing geochemical processes of Earth in a wider context. 2) The possibility of extant life: Venus almost surely once had warm oceans. The evaporation of these oceans, and subsequent escape of hydrogen, most likely resulted in an oxygenated atmosphere. The duration of this phase is poorly understood, but during this time the terrestrial planets were not isolated. Rather, due to frequent impact transport, they represented a continuous environment for early microbial life. Life, once established in the early oceans of Venus, may have migrated to the clouds which, on present day Venus, may represent a habitable niche. Though highly acidic, this aqueous environment enjoys moderate temperatures, surroundings far from chemical equilibrium, and potentially useful radiation fluxes. Observations of unusual chemistry in the clouds, and particle populations that are not well characterized, suggest that this environment must be explored much more fully before biology can be ruled out. A sulfur-based metabolism for cloud-based life on Venus has recently been proposed (Schulze-Makuch et al., 2004). While speculative, these arguments, along with the discovery of terrestrial extremophile organisms that might survive in the Venusian clouds, establish the credibility of astrobiological exploration of Venus. Arguments for the possible existence of life on Mars or Europa are, by convention and repetition, seen as more mainstream than arguments for life elsewhere, but their logical status is no different from the plausibility arguments for life on Venus. 3) Rare planetary properties of astrobiological interest: All of our ideas about extraterrestrial biochemistry are, of necessity, extrapolations from the single example of life which we have been able to study. Our planetary exploration, with an increasing focus on Astrobiology, is designed to 'follow the water'. This is a reasonable strategy but it is based, at best, on an educated guess about life's universals. If we think beyond the specifics of a particular chemical system required to build complexity and heredity, we can ask what general properties a planet must possess in order to be considered a possible candidate for life. The answers might include an atmosphere with signs of flagrant chemical disequilibrium and active, internally driven cycling of volatile elements between the surface, atmosphere and interior. At present, the two planets we know of which possess these characteristics are Earth and Venus. Bullock, M.A. and D.H. Grinspoon (2001) Icarus, 150, 19-37 Schulze-Makuch, D.H. Grinspoon., O. Abbas, L.N. Irwin and M. Bullock. (2004) . Astrobiology, 4, 11-18.

  18. Aeolian processes on Venus

    NASA Technical Reports Server (NTRS)

    Greeley, R.

    1984-01-01

    Many of the questions regarding aeolian processes on Venus and the subsequent implications for surface history involve understanding the physics of particle motion in the venusian environment. The surface environment of Venus is simulated as closely as practicable using the Venus Wind Tunnel and to determine threshold wind speeds, particle flux, particle velocities, and the characteristics of various aeolian bedforms. Despite the relatively low wind speeds on Venus, the flux of windblown material on Venus is potentially high. A high fraction of material is transported as surface creep by rolling, estimates yield rates up to 100 kg per cm lane width per year depending upon the availability of material and wind frequency, suggesting that the formation of lowland plains by aeolian processes and the burial of various landforms such as impact craters could occur on short geological time-scales. Wind tunnel simulations demonstrate that aeolian processes may be very effective in modifying the surface through erosion and deposited and may have an important influence on the composition of the atmosphere.

  19. Super-alloy, AMTEC cells for the pluto/express mission

    NASA Astrophysics Data System (ADS)

    El-Genk, Mohamed S.; Tournier, Jean-Michel; James, Ralph; Mayberry, Clay

    1999-01-01

    A number of design changes for improving the performance of super-alloy AMTEC cells, and options of integrating them to General Purpose Heat Source (GPHS) modules in the configuration proposed by Advanced Modular Power Systems were investigated, for satisfying the electric power requirements for the Pluto/Express mission. A power system consisting of 6 fresh-fuel GPHS modules and 48, 7-tube super-alloy cells connected electrically in 4 parallel strings would weight 28.75 kg and provide 174 We at EOM, at an efficiency of 13.2%. The cells' BASE brazes and evaporator temperatures would be below 1059 K and 971 K, respectively. A power system consisting of 5 fresh-fuel GPHS modules and 4 parallel strings of 8, 9-tube cells each would deliver 156 We at EOM and weight only 24.53 kg. In this system, the AMTEC cells would also operate at low BASE brazes and evaporator temperatures (1071 K and 995 K, respectively).

  20. Geologic map of the Mead quadrangle (V-21), Venus

    USGS Publications Warehouse

    Campbell, Bruce A.; Clark, David A.

    2006-01-01

    The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphere on October 12, 1994. Magellan Mission objectives included (1) improving the knowledge of the geological processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving the knowledge of the geophysics of Venus by analysis of Venusian gravity. The Mead quadrangle (V-21) of Venus is bounded by lat 0 deg and 25 deg N., long 30 deg and 60 deg E. This quadrangle is one of 62 covering Venus at 1:5,000,000 scale. Named for the largest crater on Venus, the quadrangle is dominated by effusive volcanic deposits associated with five major coronae in eastern Eistla Regio (Didilia, Pavlova, Calakomana, Isong, and Ninmah), corona-like tectonic features, and Disani Corona. The southern extremity of Bell Regio, marked by lava flows from Nyx Mons, north of the map area, forms the north-central part of the quadrangle. The shield volcanoes Kali, Dzalarhons, and Ptesanwi Montes lie south and southwest of the large corona-related flow field. Lava flows from sources east of Mead crater flood low-lying areas along the east edge of the quadrangle.

  1. ON THE FREQUENCY OF POTENTIAL VENUS ANALOGS FROM KEPLER DATA

    SciTech Connect

    Kane, Stephen R.; Kopparapu, Ravi Kumar; Domagal-Goldman, Shawn D.

    2014-10-10

    The field of exoplanetary science has seen a dramatic improvement in sensitivity to terrestrial planets over recent years. Such discoveries have been a key feature of results from the Kepler mission which utilizes the transit method to determine the size of the planet. These discoveries have resulted in a corresponding interest in the topic of the Habitable Zone and the search for potential Earth analogs. Within the solar system, there is a clear dichotomy between Venus and Earth in terms of atmospheric evolution, likely the result of the large difference (approximately a factor of two) in incident flux from the Sun. Since Venus is 95% of the Earth's radius in size, it is impossible to distinguish between these two planets based only on size. In this Letter we discuss planetary insolation in the context of atmospheric erosion and runaway greenhouse limits for planets similar to Venus. We define a ''Venus Zone'' in which the planet is more likely to be a Venus analog rather than an Earth analog. We identify 43 potential Venus analogs with an occurrence rate (?{sub ?}) of 0.32{sub ?0.07}{sup +0.05} and 0.45{sub ?0.09}{sup +0.06} for M dwarfs and GK dwarfs, respectively.

  2. Perspectives of the bistatic radar and occultation studying of the Venus atmosphere and surface

    NASA Astrophysics Data System (ADS)

    Pavelyev, Alexander; Gubenko, Vladimir; Matyugov, Stanislav; Yakovlev, Oleg

    2013-04-01

    Studying the physical properties of Venus surface and subsurface structures is an important direction in the space research. The first aim of this contribution is to present some results of reanalysis of the bistatic radar and occultation experiments provided using Venera-9, 10 and 15, 16 satellites. Comparison is made with Magellan and Venus Express bistatic radar missions. Bistatic radio images of the Venus surface is compared with monostatic radio images obtained by the Soviet and USA orbiters. The second aim consists in introducing new methods for investigation of the layered structure of the Venus atmosphere and measuring parameters of Venus surface and subsurface structures using the bistatic radar technology. The first bistatic radar measurements with spatial resolution ~ 10-20 km have been carried out during autumn of 1975 year in the five Venus equatorial regions using the Venera-9 and 10 satellites. Small roughness and, in general, plain character of relief in the investigated regions have been revealed. In 1983, the satellites Venera 15 and 16 have carried out new bistatic radar experiments with spatial resolution in the interval 5 - 10 km. New information on the large-scale topography and roughness of small-scale relief has been obtained in Northern polar areas of the planet. Some features have been detected. 1. The significant variations of the reflectivity ~ 2-4 times were found in the first region. The second area of reflectivity magnitude was far below (by three - four times) the previously measured values in the equatorial regions of Venus. These significant reflectivity variations may be related to changes in the conductivity of the ground. 2. Extremely small values roughness with rms of slopes ~ 0.20 were recorded in the northern area. 3. Both the bending angle and the reflection coefficient were determined in the experiment from the measured frequency difference between the direct and the reflected signals as a function of time, using the orbital data. New methods developed by analysis of the experimental data obtained using high-stability radio fields of the Earth's navigational satellites are introduced. For investigations of the layered structures of the Venus atmosphere a new eikonal acceleration/intensity technique is proposed. This technique allows: (1) one frequency high-precision measuring the total absorption of radio waves in the atmosphere; (2) estimating vertical gradients of the refractivity, and determining the height, slope, and horizontal displacement of the atmospheric and ionospheric layers; (3) a criterion is introduced for identification of the internal waves in the Venus atmosphere. To obtain the information on the planetary subsurface structure up to depth 1 km it is necessary to use radio waves in the Low Frequency (LF), Medium Frequency (MF), or High Frequency (HF) bands with wavelength from 1 m up 300 m. The depth of radio sounding is proportional to the wavelength, the intensity of the radio-emission source, and depends on the conductivity of the ground. The bistatic subsurface remote sensing of the planet can be achieved using powerful Earth based transmitters, and/or sporadic radio emission of the Sun and other space radio sources. The work was partly supported by Program 22 of Presidium of Russian Academy of Sciences.

  3. Probabilistic constraints from existing and future radar imaging on volcanic activity on Venus

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2015-11-01

    We explore the quantitative limits that may be placed on Venus' present-day volcanic activity by radar imaging of surface landforms. The apparent nondetection of new lava flows in the areas observed twice by Magellan suggests that there is a ~60% chance that the eruption rate is ~1 km3/yr or less, using the eruption history and area/volume flow geometry of terrestrial volcanoes (Etna, Mauna Loa and Merapi) as a guide. However, if the detection probability of an individual flow is low (e.g. ~10%) due to poor resolution or quality and unmodeled viewing geometry effects, the constraint (<10 km3/yr) is not useful. Imaging at Magellan resolution or better of only ~10% of the surface area of Venus on a new mission (30 years after Magellan) would yield better than 99% chance of detecting a new lava flow, even if the volcanic activity is at the low end of predictions (~0.01 km3/yr) and is expressed through a single volcano with a stochastic eruption history. Closer re-examination of Magellan data may be worthwhile, both to search for new features, and to establish formal (location-dependent) limits on activity against which data from future missions can be tested. While Magellan-future and future-future comparisons should offer much lower detection thresholds for erupted volumes, a probabilistic approach will be required to properly understand the implications.

  4. Mars Express - ESA sets ambitious goals for the first European mission to Mars

    NASA Astrophysics Data System (ADS)

    2003-05-01

    Mars has always fascinated human beings. No other planet has been visited so many times by spacecraft. And still, it has not been easy to unveil its secrets. Martian mysteries seem to have increased in quantity and complexity with every mission. When the first spacecraft were sent - the Mariner series in 1960s - the public was expecting an Earth ‘twin’, a green, inhabited planet full of oceans. Mariner shattered this dream by showing a barren surface. This was followed by the Viking probes which searched for life unsuccessfully in 1976. Mars appeared dry, cold and uninhabited: the Earth’s opposite. Now, two decades later, modern spacecraft have changed that view, but they have also returned more questions. Current data show that Mars was probably much warmer in the past. Scientists now think that Mars had oceans, so it could have been a suitable place for life in the past. “We do not know what happened to the planet in the past. Which process turned Mars into the dry, cold world we see today?” says Agustin Chicarro, ESA’s Mars Express project scientist. “With Mars Express, we will find out. Above all, we aim to obtain a complete global view of the planet - its history, its geology, how it has evolved. Real planetology!” Mars Express will reach the Red Planet by the end of December 2003, after a trip of just over six months. Six days before injection into its final orbit, Mars Express will eject the lander, Beagle 2, named after the ship on which Charles Darwin found inspiration to formulate his theory of evolution. The Mars Express orbiter will observe the planet and its atmosphere from a near-polar orbit, and will remain in operation for at least a whole Martian year (687 Earth days). Beagle 2 will land in an equatorial region that was probably flooded in the past, and where traces of life may have been preserved. The Mars Express orbiter carries seven advanced experiments, in addition to the Beagle 2 lander. The orbiter’s instruments have been built by group of scientific institutes from all over Europe, plus Russia, the United States, Japan and China. These instruments are a subsurface sounding radar; a high-resolution camera, several surface and atmospheric spectrometers, a plasma analyzer and a radio science experiment. The high-resolution camera will image the entire planet in full colour, in 3D, at a resolution of up to 2 metres in selected areas. One of the spectrometers will map the mineral composition of the surface with great accuracy. The missing water Data from some of the instruments will be key to finding out what happened with the water which was apparently so abundant in the past. For instance, the radar altimeter will search for subsurface water and ice, down to a depth of a few kilometres. Scientists expect to find a layer of ice or permafrost, and to measure its thickness. Other observations with the spectrometers will determine the amount of water remaining in the atmosphere. They will also tell whether there is a still a full ‘water cycle’ on Mars, for example how water is deposited in the poles and how it evaporates, depending on the seasons. "These data will determine how much water there is left. We have clear evidence for the presence of water in the past, we have seen dry river beds and sedimentary layers, and there is also evidence for water on present-day Mars. But we do not know how much water there is. Mars Express will tell us,” says Chicarro. The search for life The instruments on board Beagle 2 will investigate the geology and the climate of the landing site. But, above all, it will look for signs of life. Contrary to the Viking missions, Mars Express will search for evidence for both present and past life. Scientists are now more aware that a few biological experiments are not enough to search for life - they will combine many different types of tests to help discard contradictory results. To ‘sniff’ out direct evidence of past or present biological activity, Beagle 2’s ‘nose’ is a gas analysis package. This will determine whether carbonate mineral

  5. Wireless Seismometer for Venus

    NASA Technical Reports Server (NTRS)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Clougherty, Brian; Meredith, Roger D.; Beheim, Glenn M.; Kiefer, Walter S.; Hunter, Gary W.

    2014-01-01

    Measuring the seismic activity of Venus is critical to understanding its composition and interior dynamics. Because Venus has an average surface temperature of 462 C and the challenge of providing cooling to multiple seismometers, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents progress towards a seismometer sensor with wireless capabilities for Venus applications. A variation in inductance of a coil caused by a 1 cm movement of a ferrite probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 80 MHz in the transmitted signal from the oscillator sensor system at 420 C, which correlates to a 10 kHz mm sensitivity when the ferrite probe is located at the optimum location in the coil.

  6. Exploring Venus by Solar Airplane

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2001-01-01

    A solar-powered airplane is proposed to explore the atmospheric environment of Venus. Venus has several advantages for a solar airplane. At the top of the cloud level, the solar intensity is comparable to or greater than terrestrial solar intensities. The Earthlike atmospheric pressure means that the power required for flight is lower for Venus than that of Mars, and the slow rotation of Venus allows an airplane to be designed for continuous sunlight, with no energy storage needed for night-time flight. These factors mean that Venus is perhaps the easiest planet in the solar system for flight of a long-duration solar airplane.

  7. Planetary Radio Interferometry and Doppler Experiment (PRIDE) for studying the thermosphere of Venus

    NASA Astrophysics Data System (ADS)

    Bocanegra Bahamón, T. M.; Cimò, G.; Duev, D. A.; Gurvits, L. I.; Marty, J. C.; Molera Calvés, G.; Pogrebenko, S. V.; Rosenblatt, P.

    2013-09-01

    Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a generic experimental setup of on-board and Earth-based radio devices and facilities, which serves as an enhancement of the science return of planetary missions. The main goal of this technique is to provide precise estimates of the spacecraft state vectors, by performing precise Doppler tracking of the spacecraft carrier signal, at one or more Earth-based radio telescopes, and VLBI-style correlation of these signals in phase referencing mode [1]. By allowing an accurate examination of the changes in phase and amplitude of the radio signal propagating from the spacecraft to the multiple stations on Earth, the PRIDE technique can be used for several fields of research, among them: atmospheric and ionospheric structure of planets and their satellites, planetary gravity fields, planets' shapes, masses and ephemerides, solar plasma and different aspects of the theory of general relativity. The PRIDE-team is participating in the so-called Venus Express Atmospheric Drag Experiment (VEx-ADE) campaigns by tracking ESA's Venus Express with multiple radio telescopes on Earth. During each campaign, VEX's orbit pericenter is lowered into an altitude range of approximately 165 to 175 km in order to probe Venus upper atmosphere above its north pole. The first VExADE campaigns were carried out between 2009-2010 using Doppler tracking data acquired by the VEX radio science experiment (VeRa), which provided the first in situ measurements of the density of Venus' polar thermosphere at solar minimum conditions [2]. The last campaign was conducted in December 2012, in which the PRIDE-team participated by tracking VEX with several radio telescopes from the European VLBI Network (EVN) during pericenter passage. A Doppler frequency drop of ?40 mHz was detected as VEX reached the lowest altitudes at around 170 km. The tracking data for each pericenter pass is fitted for precise orbit determination, from which drag acceleration estimates and the corresponding atmospheric mass density estimates are derived. The results of this campaign will give the opportunity to trace the density of the polar thermosphere along the increasing phase of the solar cycle, and to provide a wider data set of density estimates which will eventually contribute to the construction of a new empirical model of Venus' polar thermosphere.

  8. Ice caps on venus?

    PubMed

    Libby, W F

    1968-03-01

    The data on Venus obtained by Mariner V and Venera 4 are interpreted as evidence of giant polar ice caps holding the water that must have come out of the volcanoes with the observed carbon dioxide, on the assumption that Earth and Venus are of similar composition and volcanic history. The measurements by Venera 4 of the equatorial surface temperature indicate that the microwave readings were high, so that the polar ice caps may be allowed to exist in the face of the 10-centimeter readings of polar temperature. Life seems to be distinctly possible at the edges of the ice sheets. PMID:17775046

  9. Topographic comparisons of uplift features on Venus and Earth: Implications for Venus tectonics

    E-print Network

    Jurdy, Donna M.

    Topographic comparisons of uplift features on Venus and Earth: Implications for Venus tectonics: Available online 12 September 2011 Keywords: Venus, Surface Earth Tectonics a b s t r a c t Venus and Earth for shaping Venus' surface. Correlations tend to improve with faster spreading rates; Venus' correlations rank

  10. Morphology and dynamics of the upper cloud layer of Venus.

    PubMed

    Markiewicz, W J; Titov, D V; Limaye, S S; Keller, H U; Ignatiev, N; Jaumann, R; Thomas, N; Michalik, H; Moissl, R; Russo, P

    2007-11-29

    Venus is completely covered by a thick cloud layer, of which the upper part is composed of sulphuric acid and some unknown aerosols. The cloud tops are in fast retrograde rotation (super-rotation), but the factors responsible for this super-rotation are unknown. Here we report observations of Venus with the Venus Monitoring Camera on board the Venus Express spacecraft. We investigate both global and small-scale properties of the clouds, their temporal and latitudinal variations, and derive wind velocities. The southern polar region is highly variable and can change dramatically on timescales as short as one day, perhaps arising from the injection of SO2 into the mesosphere. The convective cells in the vicinity of the subsolar point are much smaller than previously inferred, which we interpret as indicating that they are confined to the upper cloud layer, contrary to previous conclusions, but consistent with more recent study. PMID:18046394

  11. Possible Signs of Fauna and Flora on Venus

    NASA Astrophysics Data System (ADS)

    Ksanfomality, Leonid V.; Selivanov, Arnold S.; Gektin, Yuryi M.

    2015-08-01

    Habitability of planets is a fundamental question of science. Some of exoplanets possess physical conditions close to those of Venus. The planet Venus, despite its dense and hot (735 K) oxygen-free atmosphere of CO2, having a high pressure of 9.2 MPa at the surface, can be a natural laboratory for this kind of studies. The only existing data on the planet’s surface are still the results obtained by the Soviet VENERA landers.The TV experiments of Venera-9 and 10 (October, 1975) and Venera-13 and 14 (March, 1982) delivered 41 panoramas of Venus surface (or their fragments). The experiments were of extreme technical complexity. There have not been any similar missions to Venus in the subsequent 40 and 33 years. In the absence of new landing missions to Venus, the VENERA panoramas have been re-processed by modern means. The results of these missions are studied anew. A dozen of relatively large objects, from a decimeter to half a meter in size, with an unusual morphology have been found which moved very slowly or changed slightly their shape. Certain unusual findings that have a structure similar to the Earth’ fauna and flora were found in different areas of the planet. There are more then 30 papers on the topic published in 2012-2014 (e.g., “Acta Astronautica”, 2014, V. 105, pp. 521-533). Due to the availability of up to eight duplicates of the images obtained and their low level of masking noise, the VENERA archive panoramas permit identifying and exploring some types of hypothetical life forms of Venus. Analysis of treated once again VENERA panoramic images revealed objects that might indicate the presence of about 12 hypothetical forms of Venusian flora and fauna. Among them is ‘amisada’ that stands out with its unusual lizard shape against the stone plates surrounding it.

  12. Storms On Venus: Lightning-induced Chemistry And Predicted Products

    NASA Astrophysics Data System (ADS)

    Delitsky, M. L.; Baines, K. H.

    2012-10-01

    Observations by many spacecraft that have visited Venus over the last 40 years appear to confirm the presence of lightning storms in the Venus atmosphere. Recent observations by Venus Express indicate that lightning frequency and power is similar to that on Earth. While storms are occurring, energy deposition by lightning into Venus atmospheric constituents will immediately dissociate molecules into atoms, ions and plasma from the high temperatures in the lightning column (>30,000 K) and the associated shock waves and heating, after which these atom and ion fragments will recombine during cooldown to form new sets of molecules. Lightning will re-sort the atoms of C,O,S,N,H to create highly energetic new products. Spark and discharge experiments in the literature suggest that lightning effects on the main atmospheric molecules CO2, N2, SO2, H2SO4 and H2O will yield new molecules such as mixed carbon oxides (CnOm), mixed sulfur oxides (SnOm), oxygen (O2), elemental sulfur (Sn), nitrogen oxides (NO, N2O, NO2, NO3), sulfuric acid clusters (HnSmOx-.aHnSmOx e.g. HSO4-.mH2SO4), polysulfur oxides, carbon soot, and also halogen oxides from HCl or HF and other exotic species. Many of these molecular species may be detectable by instruments onboard Venus Express. We explore the diversity of new products likely created in the storm clouds on Venus.

  13. Sampling the Cloudtop Region on Venus

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay; Ashish, Kumar; Alam, Mofeez; Landis, Geoffrey; Widemann, Thomas; Kremic, Tibor

    2014-05-01

    The details of the cloud structure on Venus continue to be elusive. One of the main questions is the nature and identity of the ultraviolet absorber(s). Remote sensing observations from Venus Express have provided much more information about the ubiquitous cloud cover on Venus from both reflected and emitted radiation from Venus Monitoring Camera (VMC) and Visible InfraRed Imaging Spectrometer (VIRTIS) observations. Previously, only the Pioneer Venus Large Probe has measured the size distribution of the cloud particles, and other probes have measured the bulk optical properties of the cloud cover. However, the direct sampling of the clouds has been possible only below about 62 km, whereas the recent Venus Express observations indicate that the cloud tops extend from about 75 km in equatorial region to about 67 km in polar regions. To sample the cloud top region of Venus, other platforms are required. An unmanned aerial vehicle (UAV) has been proposed previously (Landis et al., 2002). Another that is being looked into, is a semi-buoyant aerial vehicle that can be powered using solar cells and equipped with instruments to not only sample the cloud particles, but also to make key atmospheric measurements - e.g. atmospheric composition including isotopic abundances of noble and other gases, winds and turbulence, deposition of solar and infrared radiation, electrical activity. The conceptual design of such a vehicle can carry a much more massive payload than any other platform, and can be controlled to sample different altitudes and day and night hemispheres. Thus, detailed observations of the surface using a miniature Synthetic Aperture Radar are possible. Data relay to Earth will need an orbiter, preferably in a low inclination orbit, depending on the latitude region selected for emphasis. Since the vehicle has a large surface area, thermal loads on entry are low, enabling deployment without the use of an aeroshell. Flight characteristics of such a vehicle have been studied (Alam et al., 2014; Kumar et al., 2014) Acknowledgements Mr. Ashish Kumar and Mr. Mofeez Alam were supported by the Indo US Forum for Science and Technology (IUSSTF) as S.N. Bose Scholars at the University of Wisconsin, Madison as Summer interns. We are grateful for the guidance support provided by Dr. Kristen Griffin and Dr. Daniel Sokol, Northrop Grumman Aerospace Corporation. References Alam, M., K. Ashish, and S.S. Limaye. Aerodynamic Analysis of BlimPlane- a Conceptual Hybrid UAV for Venus Exploration. Accepted for publication, 2014 IEEE Aerospace Conference, Big Sky, Montana, 1-8 March 2014. Ashish, K., M. Alam, and S.S. Limaye, Flight Analysis of a Venus Atmospheric Mobile Platform. Accepted for publication, 2014 IEEE Aerospace Conference, Big Sky, Montana, 1-8 March 2014. Landis, G.A., A. Colozza, C.M. LaMarre, Atmospheric flight on Venus. NASA/TM—2002-211467, AIAA-2001-0819, June 2002

  14. Venus - Lessons for earth

    NASA Technical Reports Server (NTRS)

    Hunten, D. M.

    1992-01-01

    The old idea that Venus might possess surface conditions to those of an overcast earth has been thoroughly refuted by space-age measurements. Instead, the two planets may have started out similar, but diverged because of the greater solar flux at Venus. This cannot be proved, but is consistent with everything known. A runaway greenhouse effect could have evaporated an 'ocean'. The hydrogen would escape, and most of the oxygen would be incorporated into the crust. Without liquid water, CO2 would remain in the atmosphere. Chlorine atoms would catalyze the recombination of any free oxygen back to CO2. The same theories apply to the future of the earth, and to the explanation of the polar ozone holes; the analogies are striking. There is no likelihood that the earth will actually come to resemble Venus, but Venus serves both as a warning that major environmental effects can flow from seemingly small causes, and as a testbed for the predictive models of the earth.

  15. Tectonic connections to interior processes on Venus

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1992-01-01

    The ultimate goal of geophysical/geological exploration of Venus is to relate the present tectonic (and volcanic) state of the lithosphere to interior processes, particularly mantle convection, operating both now and in the past. The Magellan mission has provided a spectacular view of the surface, and upcoming gravity measurements, particularly if the Magellan orbit is circularized, will provide significant constraints on the state of the interior. This extended abstract focuses on several controversial issues regarding venusian tectonics and its relationship to geodynamic mechanisms in the planet's interior. The origin of highlands, coronae diapir structures, and trenches and subduction are discussed.

  16. Venus transit 2004: An international education program

    NASA Astrophysics Data System (ADS)

    Mayo, L.; Odenwald, S.

    2003-04-01

    December 6th, 1882 was the last transit of the planet Venus across the disk of the sun. It was heralded as an event of immense interest and importance to the astronomical community as well as the public at large. There have been only six such occurrences since Galileo first trained his telescope on the heavens in 1609 and on Venus in 1610 where he concluded that Venus had phases like the moon and appeared to get larger and smaller over time. Many historians consider this the final nail in the coffin of the Ptolemaic, Earth centered solar system. In addition, each transit has provided unique opportunities for discovery such as measurement and refinement of the detection of Venus' atmosphere, calculation of longitudes, and calculation of the astronomical unit (and therefore the scale of the solar system). The NASA Sun Earth Connection Education Forum (SECEF) in partnership with the Solar System Exploration (SSE) and Structure and Evolution of the Universe (SEU) Forums, AAS Division for Planetary Sciences (DPS), and a number of NASA space missions and science centers are developing plans for an international education program centered around the June 8, 2004 Venus transit. The transit will be visible in its entirety from Europe and partially from the East Coast of the United States. We will use a series of robotic observatories including the Telescopes In Education (TIE) network distributed in latitude to provide observations of the transit that will allow middle and high school students to calculate the A.U. through application of parallax. We will compare the terrestrial planets in terms of the evolutionary processes that define their magnetic fields, their widely differing interactions with the solar wind, and the implications this has for life on Earth and elsewhere in the universe. We will also use Venus transit as a probe of episodes in American history (e.g. 1769: revolutionary era, 1882: post civil war era, and 2004: modern era). Museums and planetariums in the US and Europe will offer real time viewing of the transit and conduct educational programs through professional development seminars, public lectures, and planetarium shows. We are interested in soliciting advice from the research community to coordinate professional research interests with this program.

  17. Water vapor and the cloud top variations in the Venus' mesosphere from the SPICAV observations

    NASA Astrophysics Data System (ADS)

    Fedorova, Anna; Marcq, Emmanuel; Montmessin, Franck; Korablev, Oleg; Luginin, Mikhail; Bertaux, Jean-Loup

    SPICAV VIS-IR is an AOTF (acousto-optical tunable filter) spectrometer working in the spectral range of 0.65-1.7 µm onboard the Venus Express mission. It provides measurements of the H2O abundance above Venus’ clouds based on the 1.38-µm band and the cloud top altitude based on the CO2 bands in the range of 1.4-1.6 ?m. The new calibrations of the instrument in 2010-2012 allowed updating of results reported earlier. The cloud top altitude has been routinely retrieved for all dataset from 2006 to 2014 taking into account multiple-scattering in the cloudy atmosphere. The ?=1 level at 1.48 ?m varies from 69 to 73 km at lower latitudes and from 64 to 68 km at high latitudes near the Poles. The long-term and year-to-year variations were studied. The H2O mixing ratio from the 1.38 ?m band varies from 4 to 12 ppm. The variations are higher than H2O mixing ratio variations at altitudes of 68-70 km observed by VIRTIS-H/Venus Express [Cottini et al., 2012] from 2.56 ?m. The 1.38 ?m H2O band is sensitivity to altitudes of 55-70 km and a vertical gradient of water within the upper clouds can be responsible for the water behavior. The spot pointing observations for wide variations of viewing angle in the near-IR spectral range are useful to determine the vertical gradient of water within the clouds. Long-term variations of water vapor in upper clouds were not found for period from 2007 to 2014 at all range of latitudes.

  18. Second Venus spacecraft set for launch

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The launch phase of the Pioneer Venus Multiprobe spacecraft and cruise phases of both the Pioneer Venus Orbiter and the Multiprobe spacecraft are covered. Material pertinent to the Venus encounter is included.

  19. Pioneer Mars 1979 mission options

    NASA Technical Reports Server (NTRS)

    Friedlander, A. L.; Hartmann, W. K.; Niehoff, J. C.

    1974-01-01

    A preliminary investigation of lower cost Mars missions which perform useful exploration objectives after the Viking/75 mission was conducted. As a study guideline, it was assumed that significant cost savings would be realized by utilizing Pioneer hardware currently being developed for a pair of 1978 Venus missions. This in turn led to the additional constraint of a 1979 launch with the Atlas/Centaur launch vehicle which has been designated for the Pioneer Venus missions. Two concepts, using an orbiter bus platform, were identified which have both good science potential and mission simplicity indicative of lower cost. These are: (1) an aeronomy/geology orbiter, and (2) a remote sensing orbiter with a number of deployable surface penetrometers.

  20. The Venus nitric oxide night airglow: Model calculations based on the Venus thermospheric general circulation model

    SciTech Connect

    Bougher, S.W. ); Gerard, J.C. ); Stewart, A.I.F.; Fesen, C.G. )

    1990-05-01

    Pioneer Venus (PV) orbiter ultraviolet spectrometer (OUVS) images of the nightside airglow in the (0, 1) {delta} band of nitric oxide showed a maximum whose average location was at 0200 local solar time just south of the equator. The average airglow brightness calculated over a portion of the nightside for 35 early orbits during the Pioneer Venus mission was a factor of 4 lower than this maximum. Recent recalibration of the PV OUVS instrument and reanalysis of the data yield new values for this statistical maximum (1.9 {plus minus} 0.6 kR) and the nightside average (400-460 {plus minus} 120 R) nightglow. This emission is produced by radiative recombination of N and O atoms transported from their source on the dayside to the nightside by the Venus thermospheric circulation. The Venus Thermospheric General Circulation Model (VTGCM) has been extended to incorporate odd nitrogen chemistry in order to examine the dynamical and chemical processes required to give rise to this emission. Its predictions of dayside N atom densities are also compared with empirical models based on Pioneer Venus measurements. Calculations are presented corresponding to OUVS data taken during solar maximum. The average production of nitrogen atoms on the dayside is about 9.0 {times} 10{sup 9} atoms cm{sup {minus}2} s{sup {minus}1}. Approximately 30% of this dayside source is required for transport to the nightside to yield the observed dark-disk nightglow features. The statistical location and intensity of the bright spot are well reproduced, as well as the altitude of the airglow layer. The importance of the large-scale transport and eddy diffusion on the global N({sup 4}S) distribution is also evaluated.

  1. The Oldest Rocks on Venus: the Importance of Tessera Terrain for Venus Exploration (Invited)

    NASA Astrophysics Data System (ADS)

    Gilmore, M. S.; Glaze, L. S.

    2013-12-01

    Venus tessera terrain is a major, yet unsampled, tectonic unit on Venus characterized by multiple sets of intersecting compressional and extensional structures. Tessera terrain is temporally, morphologically, and perhaps also compositionally unique on Venus. Stratigraphic studies of tessera terrain establish that they consistently appear locally, and perhaps even globally, as the oldest material on a planet with an average surface crater retention age of ~500 million years. Thus, the tesserae provide the best chance to access rocks that are derived from the first 80% of the history of the planet, an era obscured by the emplacement of voluminous (presumably basaltic) plains. Analysis of Magellan imagery, topography and gravity data show that tessera terrain is characterized by higher strain rates and a thinner lithosphere than at present and thus records an extinct geodynamical era on Venus. Yet very little is understood about the number, morphology and stratigraphy of geologic units within tessera terrain, nor mass wasting processes operating on the surface. Improved radar imagery at the 5-25 m scale, and optical images below the clouds (<1 km) and at the surface will help assess the geologic processes operating in the pre-plains era. Such data products are also essential for judicious landing site selection, since tessera meter-scale roughness will limit landing site safety and sample access. Improved topography data are required to quantify the deformation recorded by ubiquitous tesserae structures that are finer than Magellan resolution. Tessera terrain is unsampled, but recent analyses of radiance from the surface at 1 micron using instruments on Venus Express and Galileo are consistent with felsic compositions for tesserae. Silicic compositions likely require both water and a plate recycling mechanism (e.g., subduction) for formation. The high D/H ratio of the Venus atmosphere is consistent with the loss of a significant inventory of water over the history of the planet. Felsic tesserae may herald from an ancient water-rich Venus, perhaps with an ocean and potentially habitable. Further assessment of tessera composition requires more comprehensive 1 micron radiance measurements from orbital, near-surface and surface platforms and in-situ measurement of mineralogy and chemistry. Radiance data need tobe supported by improved laboratory measurements of the emissivity of relevant rocks and weathering products in a Venus environment. Venus weathering experiments also support the interpretation of in situ analyses at the surface of Venus and may constrain sampling strategy. If confirmed, felsic tesserae would be critical targets for sample return due to their potential to include ancient rocks and/or minerals formed in the presence of water (e.g., zircons). In sum, the tesserae are the oldest materials exposed on the Venus surface and are the best candidates for containing ancient rocks and for comprising evolved compositions. They uniquely and critically constrain the geochemistry, geodynamics and history of water on Venus through time.

  2. Aerobraking at Venus: A science and technology enabler

    NASA Astrophysics Data System (ADS)

    Hibbard, Kenneth; Glaze, Lori; Prince, Jill

    2012-04-01

    Venus remains one of the great unexplored planets in our solar system, with key questions remaining on the evolution of its atmosphere and climate, its volatile cycles, and the thermal and magmatic evolution of its surface. One potential approach toward answering these questions is to fly a reconnaissance mission that uses a multi-mode radar in a near-circular, low-altitude orbit of ?400 km and 60-70° inclination. This type of mission profile results in a total mission delta-V of ?4.4 km/s. Aerobraking could provide a significant portion, potentially up to half, of this energy transfer, thereby permitting more mass to be allocated to the spacecraft and science payload or facilitating the use of smaller, cheaper launch vehicles.Aerobraking at Venus also provides additional science benefits through the measurement of upper atmospheric density (recovered from accelerometer data) and temperature values, especially near the terminator where temperature changes are abrupt and constant pressure levels drop dramatically in altitude from day to night.Scientifically rich, Venus is also an ideal location for implementing aerobraking techniques. Its thick lower atmosphere and slow planet rotation result in relatively more predictable atmospheric densities than Mars. The upper atmosphere (aerobraking altitudes) of Venus has a density variation of 8% compared to Mars' 30% variability. In general, most aerobraking missions try to minimize the duration of the aerobraking phase to keep costs down. These short phases have limited margin to account for contingencies. It is the stable and predictive nature of Venus' atmosphere that provides safer aerobraking opportunities.The nature of aerobraking at Venus provides ideal opportunities to demonstrate aerobraking enhancements and techniques yet to be used at Mars, such as flying a temperature corridor (versus a heat-rate corridor) and using a thermal-response surface algorithm and autonomous aerobraking, shifting many daily ground activities to onboard the spacecraft. A defined aerobraking temperature corridor, based on spacecraft component maximum temperatures, can be employed on a spacecraft specifically designed for aerobraking, and will predict subsequent aerobraking orbits and prescribe apoapsis propulsive maneuvers to maintain the spacecraft within its specified temperature limits. A spacecraft specifically designed for aerobraking in the Venus environment can provide a cost-effective platform for achieving these expanded science and technology goals.This paper discusses the scientific merits of a low-altitude, near-circular orbit at Venus, highlights the differences in aerobraking at Venus versus Mars, and presents design data using a flight system specifically designed for an aerobraking mission at Venus. Using aerobraking to achieve a low altitude orbit at Venus may pave the way for various technology demonstrations, such as autonomous aerobraking techniques and/or new science measurements like a multi-mode, synthetic aperture radar capable of altimetry and radiometry with performance that is significantly more capable than Magellan.

  3. Mariner Venus Mercury, 1973. [close flyby investigation of mercury after Venus-flyby, and observation of Kohoutek comet

    NASA Technical Reports Server (NTRS)

    Wilson, J. H.

    1973-01-01

    The Mariner Venus Mercury 1973 unmanned mission is discussed, which is designed to conduct a close flyby investigation of the planet Mercury after using the gravity-turn technique in a Venus flyby. Its scientific purposes include photographic, thermal, and spectral surveys, radio occulation, and charged particle/magnetic measurements at each planet, observation of solar-system fields and particles from 1.0 a.u. down to 0.4 a.u., and comparative planetary surveys between the Earth, the Moon, Venus, and Mercury. It is also intended to observe Kohoutek's comet. The trajectory permits establishment of a solar orbit in phase with Mercury's, permitting repeated encounters with that planet.

  4. Venus: The First Habitable World of Our Solar System?

    NASA Technical Reports Server (NTRS)

    Way, Michael Joseph; Del Genio, Anthony; Kiang, Nancy; Sohl, Linda; Clune, Tom; Aleinov, Igor; Kelley, Maxwell

    2015-01-01

    A great deal of effort in the search for life off-Earth in the past 20+ years has focused on Mars via a plethora of space and ground based missions. While there is good evidence that surface liquid water existed on Mars in substantial quantities, it is not clear how long such water existed. Most studies point to this water existing billions of years ago. However,those familiar with the Faint Young Sun hypothesis for Earth will quickly realize that this problem is even more pronounced for Mars. In this context recent simulations have been completed with the GISS 3-D GCM (1) of paleo Venus (approx. 3 billion years ago) when the sun was approx. 25 less luminous than today. A combination of a less luminous Sun and a slow rotation rate reveal that Venus could have had conditions on its surface amenable to surface liquid water. Previous work has also provided bounds on how much water Venus could have had using measured DH ratios. It is possible that less assumptions have to be made to make Venus an early habitable world than have to be made for Mars, even thoughVenus is a much tougher world on which to confirm this hypothesis.

  5. The Venus Zone: Seeking the Twin of Earth's Twin

    NASA Astrophysics Data System (ADS)

    Kane, Stephen R.; Kopparapu, Ravi Kumar; Domagal-Goldman, Shawn

    2015-01-01

    The field of exoplanetary science has seen a dramatic improvement in sensitivity to terrestrial planets over recent years. Such discoveries have been a key feature of results from the Kepler mission which utilizes the transit method to determine the size of the planet. These discoveries have resulted in a corresponding interest in the topic of the Habitable Zone (HZ) and the search for potential Earth analogs. Within the Solar System, there is a clear dichotomy between Venus and Earth in terms of atmospheric evolution, likely the result of the large difference in incident flux from the Sun. Since Venus is 95% of the Earth's radius in size, it is impossible to distinguish between these two planets based only on size. In this talk I will discuss planetary insolation in the context of atmospheric erosion and runaway greenhouse limits for planets similar to Venus. Using the ``Venus Zone'' (VZ), I will present identified potential Venus analogs from Kepler data and subsequent occurance rates of such planets.

  6. Report of the Terrestrial Bodies Science Working Group. Volume 3: Venus

    NASA Technical Reports Server (NTRS)

    Kaula, W. M.; Malin, M. C.; Masursky, H.; Pettengill, G.; Prinn, R.; Young, R. E.

    1977-01-01

    The science objectives of Pioneer Venus and future investigations of the planet are discussed. Concepts and payloads for proposed missions and the supporting research and technology required to obtain the desired measurements from space and Earth-based observations are examined, as well as mission priorities and schedules.

  7. Magellan unveils Venus

    SciTech Connect

    Lerner, E.J.

    1991-07-01

    Images obtained after an eight month Venusian year, during which the radar mapper Magellan surveyed nearly all of Venus, are described. It is observed that, instead of rigid plates moving as on earth, Venus appears covered with plumes of hot upwellings that dome out over hundreds or thousands of kilometers, feeding a continuous volcanic resurfacing of the planet. Although the Venusian surface is changing relatively rapidly by vulcanism and tectonic processes, the Magellan images make it clear that erosion is very slow. It is seen that some of the lava flows are highly fluid, etching narrow channels for hundreds of kilometers through the crust. Magellan also revealed some peculiarly Venusian formations, the tesserated areas where ridges and faults crosshatch the region into large blocks.

  8. (abstract) Venus Gravity Field

    NASA Technical Reports Server (NTRS)

    Konopliv, A. S.; Sjogren, W. L.

    1995-01-01

    A global gravity field model of Venus to degree and order 75 (5772 spherical harmonic coefficients) has been estimated from Doppler radio tracking of the orbiting spacecraft Pioneer Venus Orbiter (1979-1992) and Magellan (1990-1994). After the successful aerobraking of Magellan, a near circular polar orbit was attained and relatively uniform gravity field resolution (approximately 200 km) was obtained with formal uncertainties of a few milligals. Detailed gravity for several highland features are displayed as gravity contours overlaying colored topography. The positive correlation of typography with gravity is very high being unlike that of the Earth, Moon, and Mars. The amplitudes are Earth-like, but have significantly different gravity-topography ratios for different features. Global gravity, geoid, and isostatic anomaly maps as well as the admittance function are displayed.

  9. A Unique Approach for Studying Venus’s Atmosphere: Technology Development for the Venus Atmospheric Maneuverable Platform (VAMP)

    NASA Astrophysics Data System (ADS)

    Samuele, Rocco; Lee, Greg; Sokol, Daniel; Polidan, Ron; Griffin, Kristen; Bolisay, Linden; Michi, Yuki; Barnes, Nathan

    2014-11-01

    We are investigating a novel, reduced-risk approach to long-duration upper atmosphere exploration of Venus. The Venus Atmospheric Maneuverable Platform (VAMP) concept is a semi-buoyant plane with a science payload that can perform in situ measurements of Venus’s atmosphere. VAMP is also capable of revisiting scientifically interesting locations. Designed with a low ballistic coefficient, VAMP deploys in space and enters Venus’s atmosphere without an aeroshell. Once in the atmosphere, it can engage in a variety of science campaigns while varying its altitude between 50 and 68 km as it circumnavigates Venus. During daytime, VAMP will be able to make continuous science measurements at a range of latitudes, longitudes, and altitudes, while at night the vehicle will descend to a fully-buoyant, lower-power state, capable of performing modest science measurements at the float altitude. Near the end of VAMP’s mission life, the vehicle may attempt an end-of-life trajectory into higher latitudes or descend to lower altitudes. This presentation focuses on the technology roadmap that will allow the vehicle to accomplish these science measurements. The roadmap is driven by high priority science measurements and the technology needed to implement VAMP’s main mission phases: deployment, entry into Venus’s atmosphere, and the transition to flight and science flight performance. The roadmap includes materials tests, planform aerodynamic characterization, various subscale and full-scale packaging and deployment tests, and a full-scale suborbital flight and is being produced with extensive science community interaction to define the science measurements that would be uniquely possible with this new science platform.

  10. Long-Lived Venus Lander Conceptual Design: How To Keep It Cool

    NASA Technical Reports Server (NTRS)

    Dyson, Ridger W.; Schmitz, Paul C.; Penswick, L. Barry; Bruder, Geoffrey A.

    2009-01-01

    Surprisingly little is known about Venus, our neighboring sister planet in the solar system, due to the challenges of operating in its extremely hot, corrosive, and dense environment. For example, after over two dozen missions to the planet, the longest-lived lander was the Soviet Venera 13, and it only survived two hours on the surface. Several conceptual Venus mission studies have been formulated in the past two decades proposing lander architectures that potentially extend lander lifetime. Most recently, the Venus Science and Technology Definition Team (STDT) was commissioned by NASA to study a Venus Flagship Mission potentially launching in the 2020- 2025 time-frame; the reference lander of this study is designed to survive for only a few hours more than Venera 13 launched back in 1981! Since Cytherean mission planners lack a viable approach to a long-lived surface architecture, specific scientific objectives outlined in the National Science Foundation Decadal Survey and Venus Exploration Advisory Group final report cannot be completed. These include: mapping the mineralogy and composition of the surface on a planetary scale determining the age of various rock samples on Venus, searching for evidence of changes in interior dynamics (seismometry) and its impact on climate and many other key observations that benefit with time scales of at least a full Venus day (Le. daylight/night cycle). This report reviews those studies and recommends a hybrid lander architecture that can survive for at least one Venus day (243 Earth days) by incorporating selective Stirling multi-stage active cooling and hybrid thermoacoustic power.

  11. Three ages of Venus

    NASA Technical Reports Server (NTRS)

    Wood, Charles A.; Coombs, Cassandra R.

    1989-01-01

    A central question for any planet is the age of its surface. Based on comparative planetological arguments, Venus should be as young and active as the Earth (Wood and Francis). The detection of probable impact craters in the Venera radar images provides a tool for estimating the age of the surface of Venus. Assuming somewhat different crater production rates, Bazilevskiy et al. derived an age of 1 + or - 0.5 billion years, and Schaber et al. and Wood and Francis estimated an age of 200 to 400 million years. The known impact craters are not randomly distributed, however, thus some area must be older and others younger than this average age. Ages were derived for major geologic units on Venus using the Soviet catalog of impact craters (Bazilevskiy et al.), and the most accessible geologic unit map (Bazilevskiy). The crater counts are presented for (diameters greater than 20 km), areas, and crater densities for the 7 terrain units and coronae. The procedure for examining the distribution of craters is superior to the purely statistical approaches of Bazilevskiy et al. and Plaut and Arvidson because the bins are larger (average size 16 x 10(6) sq km) and geologically significant. Crater densities define three distinct groups: relatively heavily cratered (Lakshmi, mountain belts), moderately cratered (smooth and rolling plains, ridge belts, and tesserae), and essentially uncratered (coronae and domed uplands). Following Schaber et al., Grieve's terrestrial cratering rate of 5.4 + or - 2.7 craters greater than 20 km/10(9) yrs/10(6) sq km was used to calculate ages for the geologic units on Venus. To improve statistics, the data was aggregated into the three crater density groups, deriving the ages. For convenience, the three similar age groups are given informal time stratigraphic unit names, from youngest to oldest: Ulfrunian, Sednaian, Lakshmian.

  12. Making the Venus Concept Watch 1.0

    NASA Astrophysics Data System (ADS)

    Balint, Tibor S.; Melchiorri, Julian P.

    2014-08-01

    Over the past year we have celebrated the 50th anniversary of planetary exploration, which started with the Venus flyby of Mariner-2; and the 35th anniversary of the Pioneer-Venus multi-probe mission where one large and three small probes descended to the surface of Venus, encountering extreme environmental conditions. At the surface of Venus the temperature is about 460 °C, and the pressure is 92 bar, with a highly corrosive super-critical CO2 atmosphere. At a Venusian altitude of 50 km the pressure and temperature conditions are near Earth-like, but the clouds carry sulfuric acid droplets. Deep probe missions to Jupiter and Saturn, targeting the 100 bar pressure depth encounter similar pressure and temperature conditions as the Pioneer-Venus probes did. Mitigating these environments is highly challenging and requires special considerations for designs and materials. While assessing such space mission concepts, we have found that there is an overlap between the extreme environments in planetary atmospheres and the environments experienced by deep-sea explorers back on Earth. Consequently, the mitigation approaches could be also similar between planetary probes and diver watches. For example, both need to tolerate about 100 bar of pressure-although high temperatures are not factors on Earth. Mitigating these environments, the potential materials are: titanium for the probe and the watch housing; sapphire for the window and glass; resin impregnated woven carbon fiber for the aeroshell's thermal protection system and for the face of the watch; and nylon ribbon for the parachute and for the watch band. Planetary probes also utilize precision watches; thus there is yet another crosscutting functionality with diver watches. Our team, from the Innovation Design Engineering Program of the Royal College of Art, has designed and built a concept watch to commemorate these historical events, while highlighting advances in manufacturing processes over the past three to five decades, relevant to both future planetary mission designs and can be used to produce deep diver watches. In this paper we describe our design considerations; give a brief overview of the extreme environments these components would experience on both Venus and Earth; the manufacturing techniques and materials we used to build the Venus Watch; and its outreach potential to bring a distant concept of planetary exploration closer to Earth. We will also address lessons learned from this project and new ideas forward, for the next generation of this concept design.

  13. Venus - Dead or alive?

    NASA Technical Reports Server (NTRS)

    Taylor, Harry A., Jr.; Cloutier, Paul A.

    1986-01-01

    In situ nightside electric field observations from the Pioneer Venus Orbiter have been interpreted as evidence of extensive lightning in the lower atmosphere of Venus. The scenario, including proposed evidence of clustering of lightning over surface highland regions, has encouraged the acceptance of currently active volcanic output as part of several investigations of the dynamics and chemistry of the atmosphere and the geology of the planet. However, the correlation between the 100-hertz electric field events attributed to lightning and nightside ionization troughs resulting from the interaction of the solar wind with the ionosphere indicates that the noise results from locally generated plasma instabilities and not from any behavior of the lower atmosphere. Furthemore, analysis of the spatial distribution of the noise shows that it is not clustered over highland topography, but rather occurs at random throughout the latitude and longitude regions sampled by the orbiter during the first 5 years of operation, from 1978 to 1984. Thus the electric field observations do not identify lightning and do not provide a basis for inferring the presence of currently active volcanic output. In the absence of known evidence to the contrary, it appears that Venus is no longer active.

  14. Venus - Adivar Crater

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Many of the impact craters of Venus revealed by Magellan have characteristics unlike craters on any other planetary body. This 30-kilometer (18.6-mile) diameter crater, named Adivar crater for the Turkish educator and author Halide Adivar (1883-1964), is located just north of the western Aphrodite highland (9 degrees north latitude, 76 degrees east longitude). Surrounding the crater rim is ejected material which appears bright in the radar image due to the presence of rough fractured rock. A much broader area has also been affected by the impact, particularly to the west of the crater. Radar-bright materials, including a jet-like streak just west of the crater, extend for over 500 kilometers (310 miles) across the surrounding plains. A darker streak, in a horseshoe or paraboloidal shape, surrounds the bright area. Radar-dark (i.e., smooth) paraboloidal streaks were observed around craters in earlier Magellan images, but this is a rare bright crater streak. These unusual streaks, seen only on Venus, are believed to result from the interaction of crater materials (the meteoroid, ejecta, or both) and high-speed winds in the upper atmosphere. The precise mechanism that produces the streaks is poorly understood, but it is clear that the dense atmosphere of Venus plays an important role in the cratering process.

  15. Evaluation of Long Duration Flight on Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Colozza, Anthony J.

    2006-01-01

    An analysis was performed to evaluate the potential of utilizing either an airship or aircraft as a flight platform for long duration flight within the atmosphere of Venus. In order to achieve long-duration flight, the power system for the vehicle had to be capable of operating for extended periods of time. To accomplish these, two types of power systems were considered, a solar energy-based power system utilizing a photovoltaic array as the main power source and a radioisotope heat source power system utilizing a Stirling engine as the heat conversion device. Both types of vehicles and power systems were analyzed to determine their flight altitude range. This analysis was performed for a station-keeping mission where the vehicle had to maintain a flight over a location on the ground. This requires the vehicle to be capable of flying faster than the wind speed at a particular altitude. An analysis was also performed to evaluate the altitude range and maximum duration for a vehicle that was not required to maintain station over a specified location. The results of the analysis show that each type of flight vehicle and power system was capable of flight within certain portions of Venus s atmosphere. The aircraft, both solar and radioisotope power proved to be the most versatile and provided the greatest range of coverage both for station-keeping and non-station-keeping missions.

  16. Technology development for long-lived Venus landers.

    NASA Astrophysics Data System (ADS)

    Ekonomov, 1.; Korablev, O.; Zasova, L.

    2007-08-01

    Simultaneously with many successful lander missions on Venus in 1972-1985 Soviet Union began develop long-lived lander on surface of Venus. The basic problem were extreme conditions on a surface: P=10MPa, T=500 C . Then operations have been stopped and have renewed in 2006 already in new Russia. Mission "VENERA (VENUS) - D" is included into the Federal space program of Russia on 2006 - 2015 with launch in 2016. To this date Russia alone can't create a reliable electronics for 500 C, but we have got examples GaN electronics for 350 C. Cooling technology with boiling water is offered for interior devices of lander at pressure 10 MPa and temperature 310 C. As the power source of an electronics we use high-temperature galvanic cells on the base of Li4Si [LiCl, KCl, LiF] FeS2 which are released in Russia as reserve power sources. They are capable to work directly on a surface of Venus without any thermal protection. At lander two kinds of vacuum technology can be used: 1) in multilayer (MLI ) thermal blanket for lander, 2) in electro-vacuum devices, for example transmitter . For creation and maintenance of vacuum at temperature 400-500 C: chemical gas absorbers ( getter materials ) are used, they actively absorb both carbon dioxide and nitrogen .

  17. Russian mission Venera-D - new conception

    NASA Astrophysics Data System (ADS)

    Zasova, L. V.; Zelenyi, L. M.; Korablev, O. I.; Khartov, V. V.; Pichkhadze, K. M.; Vorontsov, V. A.; Marov, M. Y.; Elkin, K. S.; Sanko, N. F.; Voron, V. V.; Basilevsky, A. T.; Gavrik, A. L.; Khavroshkin, O. B.; Tuchin, A. N.; Skalsky, A.

    2011-10-01

    The mission Venera-D is included in the Russian Federal Space Program (2006-2015), being in phase A now. The aim of the mission is investigation of the surface, atmosphere and plasma environment of Venus to understand the formation and evolution of the planet and its atmosphere.

  18. Venus clouds: structure and composition.

    PubMed

    Young, A T

    1974-02-01

    The clouds of Venus consist of a fine sulfuric acid aerosol similar to that found in the earth's stratosphere. The acid aerosol on Venus appears to be uniformly mixed with the gas, at least in the visible layers, and possibly down to the cloud base. PMID:17781929

  19. Pioneer Venus radar mapper experiment

    USGS Publications Warehouse

    Pettengill, G.H.; Ford, P.G.; Brown, W.E.; Kaula, W.M.; Keller, C.H.; Masursky, H.; McGill, G.E.

    1979-01-01

    Altimetry and radar scattering data for Venus, obtained from 10 of the first 13 orbits of the Pioneer Venus orbiter, have disclosed what appears to be a rift valley having vertical relief of up to 7 kilometers, as well as a neighboring, gently rolling plain. Planetary oblateness appears unlikely to exceed 112500 and may be substantially smaller. Copyright ?? 1979 AAAS.

  20. The thermal conditions of Venus

    NASA Technical Reports Server (NTRS)

    Zharkov, Vladimir N.; Solomatov, V. S.

    1991-01-01

    Models of Venus' thermal evolution are examined. The following subject areas are covered: (1) modified approximation of parameterized convection; (2) description of the model; (3) numerical results and asymptotic solution of the MAPC equations; (4) magnetism and the thermal regime of the cores of Earth and Venus; and (5) the thermal regime of the Venusian crust.

  1. Descenso al Infierno de Venus Manuel Alfonseca

    E-print Network

    Alfonseca, Manuel

    Descenso al Infierno de Venus Manuel Alfonseca #12;Manuel Alfonseca 2 #12;Descenso al infierno de Venus 3 Descenso al infierno de Venus Manuel Alfonseca RESERVADOS TODOS LOS DERECHOS. Salvo usos ........................................131 #12;Descenso al infierno de Venus 5 Tres días antes de la partida teve MacDunn no se sorprendió al

  2. The Night Sky Venus Dazzles after Sunset

    E-print Network

    Luttermoser, Donald G.

    The Night Sky Venus Dazzles after Sunset At dusk the planet Venus is dazzling bright, low in the southwest sky in October. Venus will set 1¾ hours after the sun at the beginning of the month , Venus will have a close conjunction to the red supergiant star Antares, where Antares

  3. Venus 2012 transit: spectroscopy and high resolution

    E-print Network

    Widemann, Thomas

    Venus 2012 transit: spectroscopy and high resolution observations proposals by Cyril Bazin, Serge the structuration of Venus upper atmosphere ? 2012 Venus transit : Better understanding these upper layers the Venus thick atmosphere >>> -tentative spectroscopic exp-t prepared at the 1m diam. Solar Tel

  4. Non-Cooled Power System for Venus Lander

    NASA Technical Reports Server (NTRS)

    Salazar, Denise; Landis, Geoffrey A.; Colozza, Anthony J.

    2014-01-01

    The Planetary Science Decadal Survey of 2013-2022 stated that the exploration of Venus is of significant interest. Studying the seismic activity of the planet is of particular importance because the findings can be compared to the seismic activity of Earth. Further, the geological and atmospheric properties of Venus will shed light into the past and future of Earth. This paper presents a radioisotope power system (RPS) design for a small low-power Venus lander. The feasibility of the new power system is then compared to that of primary batteries. A requirement for the power source system is to avoid moving parts in order to not interfere with the primary objective of the mission - to collect data about the seismic activity of Venus using a seismometer. The target mission duration of the lander is 117 days, a significant leap from Venera 13, the longest-lived lander on the surface of Venus, which survived for 2 hours. One major assumption for this mission design is that the power source system will not provide cooling to the other components of the lander. This assumption is based on high-temperature electronics technology that will enable the electronics and components of the lander to operate at Venus surface temperature. For the proposed RPS, a customized General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHSRTG) is designed and analyzed. The GPHS-RTG is chosen primarily because it has no moving parts and it is capable of operating for long duration missions on the order of years. This power system is modeled as a spherical structure for a fundamental thermal analysis. The total mass and electrical output of the system are calculated to be 24 kilograms and 26 Watts, respectively. An alternative design for a battery-based power system uses Sodium Sulfur batteries. To deliver a similar electrical output for 117 days, the battery mass is calculated to be 234 kilograms. Reducing mission duration or power required will reduce the required battery mass. Finally, the advantages and disadvantages of both power systems with regard to science return, risk, and cost are briefly compared. The design of the radioisotope power system is considerably riskier because it is novel and would require additional years of further refinement, manufacturing, safety analysis, and testing that the primary batteries do not need. However, the lifetime of the radioisotope power system makes its science return more promising.

  5. Venus atmosphere and extreme surface topography

    NASA Astrophysics Data System (ADS)

    Zasova, L.; Khatuntsev, I.; Patsaeva, M.; Ignatiev, N.; Rodin, A.; Turin, A.; Markiewicz, W.; Piccioni, G.

    2015-10-01

    The temperature fields at several levels in the Venus mesosphere(60-95 km)as well as the altitude of the upper boundary of clouds retrieved from Venera-15 (FS-V15) [1], and the zonal wind fields and albedo of the upper clouds, measured by VMC Venus Express [2], and altitude of the upper boundary of clouds VIRTIS-M VEX [3] data are compared with the topographic map, obtained by Magellan [4] . The results show that the isotherms and the altitude isolines of the upper clouds boundary reproduce the extended surface features Ishtar and Atalanta Planitia. In turn, the shapes of wind isovelocities and albedo at the upper boundary of clouds (VMC) closely follow the details of relief of Terra Aphrodite as well the isolines of altitude of the cloud tops (VIRTIS). In all cases the isolines are shifted with respect to topography by about 30° in the direction of superrotation. Non-hydrostatic general circulation model of the Venus atmosphere[5] demonstrates that the major topographic features such as Maxwell Montes and Terra Aphrodite provide a prominent impact on the atmospheric dynamics at levels as high as 90-95 km.

  6. Changes in apoptotic microRNA and mRNA expression profiling in Caenorhabditis elegans during the Shenzhou-8 mission

    PubMed Central

    Gao, Ying; Li, Shuai; Xu, Dan; Wang, Junjun; Sun, Yeqing

    2015-01-01

    Radiation and microgravity exposure have been proven to induce abnormal apoptosis in microRNA (miRNA) and mRNA expression, but whether space conditions, including radiation and microgravity, activate miRNAs to regulate the apoptosis is undetermined. For that purpose, we investigated miRNome and mRNA expression in the ced-1 Caenorhabditis elegans mutant vs the wild-type, both of which underwent spaceflight, spaceflight 1g-centrifuge control and ground control conditions during the Shenzhou-8 mission. Results showed that no morphological changes in the worms were detected, but differential miRNA expression increased from 43 (ground control condition) to 57 and 91 in spaceflight and spaceflight control conditions, respectively. Microgravity altered miRNA expression profiling by decreasing the number and significance of differentially expressed miRNA compared with 1 g incubation during spaceflight. Alterations in the miRNAs were involved in alterations in apoptosis, neurogenesis larval development, ATP metabolism and GTPase-mediated signal transduction. Among these, 17 altered miRNAs potentially involved in apoptosis were screened and showed obviously different expression signatures between space conditions. By integrated analysis of miRNA and mRNA, miR-797 and miR-81 may be involved in apoptosis by targeting the genes ced-10 and both drp-1 and hsp-1, respectively. Compared with ground condition, space conditions regulated apoptosis though a different manner on transcription, by altering expression of seven core apoptotic genes in spaceflight condition, and eight in spaceflight control condition. Results indicate that, miRNA of Caenorhabditis elegans probably regulates apoptotic gene expression in response to space environmental stress, and shows different behavior under microgravity condition compared with 1 g condition in the presence of space radiation. PMID:26286471

  7. Changes in apoptotic microRNA and mRNA expression profiling in Caenorhabditis elegans during the Shenzhou-8 mission.

    PubMed

    Gao, Ying; Li, Shuai; Xu, Dan; Wang, Junjun; Sun, Yeqing

    2015-11-01

    Radiation and microgravity exposure have been proven to induce abnormal apoptosis in microRNA (miRNA) and mRNA expression, but whether space conditions, including radiation and microgravity, activate miRNAs to regulate the apoptosis is undetermined. For that purpose, we investigated miRNome and mRNA expression in the ced-1 Caenorhabditis elegans mutant vs the wild-type, both of which underwent spaceflight, spaceflight 1g-centrifuge control and ground control conditions during the Shenzhou-8 mission. Results showed that no morphological changes in the worms were detected, but differential miRNA expression increased from 43 (ground control condition) to 57 and 91 in spaceflight and spaceflight control conditions, respectively. Microgravity altered miRNA expression profiling by decreasing the number and significance of differentially expressed miRNA compared with 1 g incubation during spaceflight. Alterations in the miRNAs were involved in alterations in apoptosis, neurogenesis larval development, ATP metabolism and GTPase-mediated signal transduction. Among these, 17 altered miRNAs potentially involved in apoptosis were screened and showed obviously different expression signatures between space conditions. By integrated analysis of miRNA and mRNA, miR-797 and miR-81 may be involved in apoptosis by targeting the genes ced-10 and both drp-1 and hsp-1, respectively. Compared with ground condition, space conditions regulated apoptosis though a different manner on transcription, by altering expression of seven core apoptotic genes in spaceflight condition, and eight in spaceflight control condition. Results indicate that, miRNA of Caenorhabditis elegans probably regulates apoptotic gene expression in response to space environmental stress, and shows different behavior under microgravity condition compared with 1 g condition in the presence of space radiation. PMID:26286471

  8. VENUS-2 Experimental Benchmark Analysis

    SciTech Connect

    Pavlovichev, A.M.

    2001-09-28

    The VENUS critical facility is a zero power reactor located at SCK-CEN, Mol, Belgium, which for the VENUS-2 experiment utilized a mixed-oxide core with near-weapons-grade plutonium. In addition to the VENUS-2 Core, additional computational variants based on each type of fuel cycle VENUS-2 core (3.3 wt. % UO{sub 2}, 4.0 wt. % UO{sub 2}, and 2.0/2.7 wt.% MOX) were also calculated. The VENUS-2 critical configuration and cell variants have been calculated with MCU-REA, which is a continuous energy Monte Carlo code system developed at Russian Research Center ''Kurchatov Institute'' and is used extensively in the Fissile Materials Disposition Program. The calculations resulted in a k{sub eff} of 0.99652 {+-} 0.00025 and relative pin powers within 2% for UO{sub 2} pins and 3% for MOX pins of the experimental values.

  9. Properties of particles in the upper clouds of Venus in the UV-dark and -bright regions as retrieved from the UV and near-IR VMC/VEx images

    NASA Astrophysics Data System (ADS)

    Petrova, E. V.; Shalygina, O. S.; Markiewicz, W. J.

    2015-10-01

    The nature of ultraviolet contrasts observed on the upper cloud deck of Venus is still not known. To constrain better the properties of particles that may cause the UV contrasts, the phase dependences of brightness of the Venus clouds measured by the UV (0.365 ?m) and near-IR (0.965 ?m) channels of the Venus Monitoring Camera (VMC of the Venus Express mission) in the UV-dark and -bright regions are jointly analyzed. It was found that:(1) Variations in the composition of submicron particles in the clouds play a key role in the UV contrasts at low latitudes near the local noon. (2) In the pairs of UV-dark and -bright regions, the sizes of the 1-?m mode of cloud particles are the same. (3) The radius of particles in the upper clouds at mid latitudes decreases with latitude: from 1.05-1.2 ?m at ?36?S to 0.8-0.9 ?m at ?62?S. (4) An additional amount of nonabsorbing 0.9-?m particles at the cloud top produces the UV-bright bands at ?50?S.

  10. Hansen, V.L., and Young, D.A., 2007, Venus's evolution: A synthesis, in Cloos, M., Carlson, W.D., Gilbert, M.C., Liou, J.G., and Sorensen, S.S., eds., Convergent Margin Terranes and Associated Regions: A Tribute to W.G. Ernst: Geological Society of Americ

    E-print Network

    Hansen, Vicki

    255 Hansen, V.L., and Young, D.A., 2007, Venus's evolution: A synthesis, in Cloos, M., Carlson, W. Geological Society of America Special Paper 419 2007 Venus's evolution: A synthesis V.L. Hansen Department (National Aeronautics and Space Administration) Magellan mission to Venus was the preservation of ~970

  11. Plasma vortices, lateral forcing, and the superrotating Venus atmosphere

    NASA Astrophysics Data System (ADS)

    Lundin, R.; Barabash, S.; Futaana, S.; Holmstrom, M.; Perez-de-Tejada, H.; Sauvaud, J.-A.

    2012-04-01

    New observations from Venus Express (VEX) show the existence of a large-scale vortex-like ion flow pattern in the Venus plasma tail. The flow pattern is characterized by besides a dominating antisunward flow, also a lateral flow component of solar wind (H+) and ionospheric (O+) ions. The lateral flow component is directed opposite to the Venus orbital motion. A test of the energy and momentum balance between solar wind H+ and ionospheric O+ indicates that the energy and momentum delivered to O+ is proportional to the loss of energy and momentum by solar wind H+. The combined antisunward and lateral H+ and O+ flow wraps over the planetary atmosphere, from the terminator into the nightside. The net lateral flow near Venus is in the direction of the Venus atmospheric superrotation. Further down in the Venus plasma tail the flow display a circular motion around the central tail axis. The general agreement in direction between the nightside ion flow over the Northern hemisphere, and the retrograde motion of the Venus atmosphere, implies a cause-effect relation between the ionospheric O+ flow and the atmospheric neutral flow. This underlying connection is further strengthened by the fact the the O+ flow velocity in the 200-300 km altitude range follows the same power law curve as that fitted to the atmospheric zonal wind velocity profile [1]. The combined ion + neutral wind profile therefore implies momentum balance between the ionospheric and atmospheric retrograde flow. The fact that the O+ flow is driven by solar wind forcing leaves us with the question: Is the superrotating upper atmosphere at Venus a consequence of solar wind forcing? Is the ion flow capable of accelerating, and maintaining, a superrotating upper atmosphere at Venus? Combining ion data [2] with a fluid dynamic model of the energy and momentum transfer of ions to neutrals we find that this is certainly possible. The ionospheric O+ energy and momentum observed is sufficient to accelerate, and maintain superrotating velocites, after a few million years - minute compared to evolutionary time scales of a planet. [1] Schubert G., C. Covey, A. Del Genio, L.S. Elson et al., J. Geophys. Res., 85, 8007-8025, 1980 [2] Lundin, R.; Barabash, S.; Futaana, Y.; Sauvaud, J.-A.; Fedorov, A.; Perez-de-Tejada, H., Ion flow and momentum transfer in the Venus plasma environment, Icarus, 215, 751-758, 2011

  12. Stagnation Point Radiative Heating Relations for Venus Entry

    NASA Technical Reports Server (NTRS)

    Tauber, Michael E.; Palmer, Grant E.; Prabhu, Dinesh K.

    2012-01-01

    Improved analytic expressions for calculating the stagnation point radiative heating during entry into the atmosphere of Venus have been developed. These analytic expressions can be incorporated into entry trajectory simulation codes. Together with analytical expressions for convective heating at the stagnation point, the time-integrated total heat load at the stagnation point is used in determining the thickness of protective material required, and hence the mass of the fore body heatshield of uniform thickness.

  13. Using the transit of Venus to probe the upper planetary atmosphere.

    PubMed

    Reale, Fabio; Gambino, Angelo F; Micela, Giuseppina; Maggio, Antonio; Widemann, Thomas; Piccioni, Giuseppe

    2015-01-01

    During a planetary transit, atoms with high atomic number absorb short-wavelength radiation in the upper atmosphere, and the planet should appear larger during a primary transit observed in high-energy bands than in the optical band. Here we measure the radius of Venus with subpixel accuracy during the transit in 2012 observed in the optical, ultraviolet and soft X-rays with Hinode and Solar Dynamics Observatory missions. We find that, while Venus's optical radius is about 80?km larger than the solid body radius (the top of clouds and haze), the radius increases further by >70?km in the extreme ultraviolet and soft X-rays. This measures the altitude of the densest ion layers of Venus's ionosphere (CO2 and CO), useful for planning missions in situ, and a benchmark case for detecting transits of exoplanets in high-energy bands with future missions, such as the ESA Athena. PMID:26102562

  14. Using the transit of Venus to probe the upper planetary atmosphere

    PubMed Central

    Reale, Fabio; Gambino, Angelo F.; Micela, Giuseppina; Maggio, Antonio; Widemann, Thomas; Piccioni, Giuseppe

    2015-01-01

    During a planetary transit, atoms with high atomic number absorb short-wavelength radiation in the upper atmosphere, and the planet should appear larger during a primary transit observed in high-energy bands than in the optical band. Here we measure the radius of Venus with subpixel accuracy during the transit in 2012 observed in the optical, ultraviolet and soft X-rays with Hinode and Solar Dynamics Observatory missions. We find that, while Venus's optical radius is about 80?km larger than the solid body radius (the top of clouds and haze), the radius increases further by >70?km in the extreme ultraviolet and soft X-rays. This measures the altitude of the densest ion layers of Venus's ionosphere (CO2 and CO), useful for planning missions in situ, and a benchmark case for detecting transits of exoplanets in high-energy bands with future missions, such as the ESA Athena. PMID:26102562

  15. Using the transit of Venus to probe the upper planetary atmosphere

    NASA Astrophysics Data System (ADS)

    Reale, Fabio; Gambino, Angelo F.; Micela, Giuseppina; Maggio, Antonio; Widemann, Thomas; Piccioni, Giuseppe

    2015-06-01

    During a planetary transit, atoms with high atomic number absorb short-wavelength radiation in the upper atmosphere, and the planet should appear larger during a primary transit observed in high-energy bands than in the optical band. Here we measure the radius of Venus with subpixel accuracy during the transit in 2012 observed in the optical, ultraviolet and soft X-rays with Hinode and Solar Dynamics Observatory missions. We find that, while Venus's optical radius is about 80 km larger than the solid body radius (the top of clouds and haze), the radius increases further by >70 km in the extreme ultraviolet and soft X-rays. This measures the altitude of the densest ion layers of Venus's ionosphere (CO2 and CO), useful for planning missions in situ, and a benchmark case for detecting transits of exoplanets in high-energy bands with future missions, such as the ESA Athena.

  16. Tectonic resurfacing of Venus

    NASA Technical Reports Server (NTRS)

    Malin, Michael C.; Grimm, Robert E.; Herrick, Robert R.

    1993-01-01

    Impact crater distributions and morphologies have traditionally played an important role in unraveling the geologic histories of terrestrial objects, and Venus has proved no exception. The key observations are: mean crater retention age about 500 Ma; apparently random spatial distribution; modest proportion (17 percent) of modified craters; and preferential association of modified craters with areas of low crater density. The simplest interpretation of these data alone is that Venus experienced global resurfacing (assumed to be largely volcanic) prior to 500 Ma, after which time resurfacing rates decreased dramatically. This scenario does not totally exclude present geological activity: some resurfacing and crater obliteration is occurring on part of the planet, but at rates much smaller than on Earth. An alternative endmember model holds that resurfacing is also spatially randomly distributed. Resurfacing of about 1 sq km/yr eliminates craters such that a typical portion of the surface has an age of 500 Ma, but actual ages range from zero to about 1000 Ma. Monte Carlo simulation indicates that the typical resurfacing 'patch' cannot exceed about 500 km in diameter without producing a crater distribution more heterogeneous than observed. Volcanic or tectonic processes within these patches must be locally intense to be able to obliterate craters completely and leave few modified. In this abstract, we describe how global geologic mapping may be used to test resurfacing hypotheses. We present preliminary evidence that the dominant mode of resurfacing on Venus is tectonism, not volcanism, and that this process must be ongoing today. Lastly, we outline a conceptual model in which to understand the relationship between global tectonics and crater distribution and preservation.

  17. Geologic Map of the Mylitta Fluctus Quadrangle (V-61), Venus

    USGS Publications Warehouse

    Ivanov, Mikhail A.; Head, James W., III

    2006-01-01

    INTRODUCTION The Magellan Mission The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphere on October 12, 1994. Magellan Mission objectives included: (1) improving knowledge of the geological processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology, and (2) improving the knowledge of the geophysics of Venus by analysis of Venusian gravity. The Magellan spacecraft carried a 12.6-cm radar system to map the surface of Venus. The transmitter and receiver systems were used to collect three data sets: (1) synthetic aperture radar (SAR) images of the surface, (2) passive microwave thermal emission observations, and (3) measurements of the backscattered power at small angles of incidence, which were processed to yield altimetric data. Radar imaging, altimetric, and radiometric mapping of the Venusian surface was done in mission cycles 1, 2, and 3 from September 1990 until September 1992. Ninety-eight percent of the surface was mapped with radar resolution on the order of 120 meters. The SAR observations were projected to a 75-m nominal horizontal resolution, and these full-resolution data compose the image base used in geologic mapping. The primary polarization mode was horizontal-transmit, horizontal-receive (HH), but additional data for selected areas were collected for the vertical polarization sense. Incidence angles varied between about 20? and 45?. High resolution Doppler tracking of the spacecraft took place from September 1992 through October 1994 (mission cycles 4, 5, 6). Approximately 950 orbits of high-resolution gravity observations were obtained between September 1992 and May 1993 while Magellan was in an elliptical orbit with a periapsis near 175 km and an apoapsis near 8,000 km. An additional 1,500 orbits were obtained following orbit-circularization in mid-1993. These data exist as a 75? by 75? harmonic field.

  18. Pioneer Venus gas chromatography of the lower atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Oyama, V. I.; Carle, G. C.; Woeller, F.; Pollack, J. B.; Reynolds, R. T.; Craig, R. A.

    1980-01-01

    A gas chromatograph mounted in the Pioneer Venus sounder probe measured the chemical composition of the atmosphere of Venus at three altitudes. Ne, N2, O2, Ar, CO, H2O, SO2, and CO2 were measured, and upper limits set for H2, COS, H2S, CH4, Kr, N2O, C2H4, C2H6, and C3H8. Simulation studies have provided indirect evidence for sulfuric acid-like droplets and support the possibility of water vapor at altitudes of 42 and 24 km. The paper discusses the implications of these results for the origin, evolution, and present state of Venus' atmosphere.

  19. Venus Monthly Bibliography Compiled by Minh N. Le

    E-print Network

    Rathbun, Julie A.

    propagation within the Venusian lithosphere, Journal of Geophysical Research-Planets, 120(7), 1279-1297, doi, Journal of Geophysical Research-Space Physics, 120(7), 5593-5602, doi: http://dx.doi.org/10.1002/2015ja inversion of the Venus Express radio occultation data observed by Shanghai 25 m and New Norcia 35 m antennas

  20. Little or no solar wind enters Venus' atmosphere at solar minimum.

    PubMed

    Zhang, T L; Delva, M; Baumjohann, W; Auster, H-U; Carr, C; Russell, C T; Barabash, S; Balikhin, M; Kudela, K; Berghofer, G; Biernat, H K; Lammer, H; Lichtenegger, H; Magnes, W; Nakamura, R; Schwingenschuh, K; Volwerk, M; Vörös, Z; Zambelli, W; Fornacon, K-H; Glassmeier, K-H; Richter, I; Balogh, A; Schwarzl, H; Pope, S A; Shi, J K; Wang, C; Motschmann, U; Lebreton, J-P

    2007-11-29

    Venus has no significant internal magnetic field, which allows the solar wind to interact directly with its atmosphere. A field is induced in this interaction, which partially shields the atmosphere, but we have no knowledge of how effective that shield is at solar minimum. (Our current knowledge of the solar wind interaction with Venus is derived from measurements at solar maximum.) The bow shock is close to the planet, meaning that it is possible that some solar wind could be absorbed by the atmosphere and contribute to the evolution of the atmosphere. Here we report magnetic field measurements from the Venus Express spacecraft in the plasma environment surrounding Venus. The bow shock under low solar activity conditions seems to be in the position that would be expected from a complete deflection by a magnetized ionosphere. Therefore little solar wind enters the Venus ionosphere even at solar minimum. PMID:18046399

  1. Pioneer Venus Unified Abstract Data Library and Quick Look Data Delivery System

    NASA Technical Reports Server (NTRS)

    Ferandin, J. A.; Weeks, C. L.; Pak, R. D.

    1980-01-01

    Development of the Pioneer Venus (PV) Unified Abstract Data System (UADS) and Quick Look Data System (QLDS) was prompted by the need to provide PV investigators rapid and easy access to PV mission data. The UADS is intended to maximize the scientific benefits of the mission by facilitating the exchange of reduced scientific data. QLDS provides a method by which sampled daily mission data is rapidly transmitted to principal investigators providing them a quick look at that orbit's data.

  2. Potential Vorticity of the South Polar Vortex of Venus

    NASA Astrophysics Data System (ADS)

    Garate-Lopez, I.; Hueso, R.; Sánchez-Lavega, A.

    2015-10-01

    The atmospheric vortex at the southern pole of Venus is highly variable in morphology and unpredictable in its dynamical behavior. Using infrared images from the VIRTIS-M instrument onboard Venus Express we have built maps of Ertel's potential vorticity at the lower and upper clouds (altitudes~4 1-45km and ~55-62km above the surface). For this purpose, we have combined the wind field at both clouds'levels and the three-dimensional thermal structure that we previously measured [1, 2].

  3. Short Large-Amplitude Magnetic Structures (SLAMS) at Venus

    NASA Technical Reports Server (NTRS)

    Collinson, G. A.; Wilson, L. B.; Sibeck, D. G.; Shane, N.; Zhang, T. L.; Moore, T. E.; Coates, A. J.; Barabash, S.

    2012-01-01

    We present the first observation of magnetic fluctuations consistent with Short Large-Amplitude Magnetic Structures (SLAMS) in the foreshock of the planet Venus. Three monolithic magnetic field spikes were observed by the Venus Express on the 11th of April 2009. The structures were approx.1.5->11s in duration, had magnetic compression ratios between approx.3->6, and exhibited elliptical polarization. These characteristics are consistent with the SLAMS observed at Earth, Jupiter, and Comet Giacobini-Zinner, and thus we hypothesize that it is possible SLAMS may be found at any celestial body with a foreshock.

  4. Tectonics and evolution of Venus

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.; Kaula, W. M.; Mcgill, G. E.; Malin, M. C.

    1981-01-01

    Earlier data synthesized with data recently obtained by the Pioneer Venus Orbiter are analyzed with regard to general tectonics, interior, and long-term evolution of Venus. Comprehensive topographic maps, global properties of Venus, and variations in its gravity field are investigated, and bulk properties of Venus, earth, Mars, the sun, and chondritic meteorites relevant to planetary internal structure and evolution are studied. Although Venus was found to differ less than 30% from earth in comparing all important bulk properties, it appears to have evolved differently. It is noted that a slow rotation rate, the absence of a satellite, the virtual absence of a magnetic field, the dearth of water in the atmosphere, the abundance of primordial argon, and the high surface temperature, are properties in which Venus differs most from the earth. Further results showing the positive correlation of gravity and topography at all wavelengths and the apparent absence of any feature like an ocean indicate that Venus is a one-plate planet and its evolution apparently resembles that of Mars more than that of the earth.

  5. Naming the newly found landforms on Venus

    NASA Technical Reports Server (NTRS)

    Batson, R. M.; Russell, J. F.

    1991-01-01

    The mapping of Venus is unique in the history of cartigraphy; never has so much territory been discovered and mapped in so short a period of time. Therefore, in the interest of international scientific communication, there is a unique urgency to the development of a system of names for surface features on Venus. The process began with the naming of features seen on radar images taken from Earth and continued through mapping expeditions of the U.S. and U.S.S.R. However, the Magellan Mission resolves features twenty-five times smaller than those mapped previously, and its radar data will cover an area nearly equivalent to that of the continents and the sea-floors of the Earth combined. The International Astronomical Union (IAU) was charged with the formal endorsement of names of features on the planets. Proposed names are collected, approved, and applied through the IAU Working Group for Planetary System Nomenclature (WGPSN) and its task groups, prior to IAU approval by the IAU General Assembly. Names approved by the WGPSN and its task groups, prior to final approval may be used on published maps and articles, provided that their provisional nature is stipulated. The IAU has established themes for the names to be used on each of the planets; names of historical and mythological women are used on Venus. Names of political entities and those identified with active religions are not acceptable, and a person must have been deceased for three years or more to be considered. Any interested person may propose a name for consideration by the IAU.

  6. Chemical reactions between Venus' surface and atmosphere - An update. (Invited)

    NASA Astrophysics Data System (ADS)

    Treiman, A. H.

    2013-12-01

    The surface of Venus, at ~740K, is hot enough to allow relatively rapid chemical reactions between it and the atmosphere, i.e. weathering. Venus chemical weathering has been explored in detail [1], to the limits of available data. New data from Venus Express (VEx) and new ideas from exoplanets have sparked a modest renewal of interest in Venus weathering. Venus' surface cannot be observed in visible light, but there are several NIR ';windows' through its atmosphere that allow surface imaging. The VIRTIS spectrometer on VEx viewed the surface through one window [2]; emissivity variations among lava flows on Imdr and Themis Regios have been explained as varying degrees of weathering, and thus age [3]. The VMC camera on VEx also provides images through a NIR window, which suggest variable degrees of weathering on some basaltic plains [4]. Indirect evidence for weathering may come from varying SO2 abundance at Venus' cloud tops; repeated rapid increases and gradual declines may represent volcanic eruptions followed by weathering to form sulfate minerals [5]. Continued geochemical modeling relevant to Venus weathering is motivated by expolanet studies [6]. Models have been extended to hypothetical exo-Venuses of different temperatures and surface compositions [7]. The idea that Venus' atmosphere composition can be buffered by reaction with its surface was explored in detail, and the derived constraint extended to other types of planets [8]. Several laboratories are investigating Venus weathering, motivated in part by the hope that they can provide real constraints on timescales of Venus volcanism [3]. Aveline et al. [9] are extending early studies [10] by reacting rocks and minerals with concentrated SO2 (to accelerate reaction rates to allow detectability of products). Kohler et al. [11] are investigating the stability of metals and chalcogenides as possible causes of the low-emissivity surfaces at high elevations. Berger and Aigouy [12] studied rock alteration on a hypothetical early Venus with a water-rich atmosphere. Martin et al. [13] investigated the fate of weathered rock when heated (by igneous or impact events). Our understanding of Venus' geological history is stymied by a lack of data - spacecraft observations of and/or at its surface. VMC on VEx may continue to provide new data on surface emissivity, but their interpretation is inherently ambiguous. Laboratory experiments seem the most promising approach - attempting to quantify rates of weathering and thus volcanism [3], and (with luck) framing significant problems that can be directly answered by spacecraft observations. [1] Fegley B.Jr. et al. (1997) In Venus II. U. Ariz. Press. p. 591. [2] Helbert J. et al. (2008) GRL 35, L11201. [3] Smrekar S.E et al. (2010) Science 328, 605-608. [4] Basilevsky A.T. et al. (2012) Icarus 217, 434-450. [5] Marcq E. et al. (2013) Nature Geoscience 6, 25-28. [6] Kane S.R. et al. (2013) Astrophysical J. 770, L20. [7] Schaefer L. & Fegley B.Jr. (2011) Astrophysical J. 729, 6. [8] Treiman A.H. & Bullock M.A. (2012) Icarus 217, 534-541. [9] Aveline D.C. et al. (2011) Lunar Planet. Sci. Conf. 42, Abstr. #2165. [10] Fegley B.Jr. & Prinn R.G. (1989) Nature 337, 55-58. [11] Kohler E. et al. (2012) Lunar Planet. Sci. Conf. 43, Abstr. #2749. [12] Berger G. & Aigouy T. (2011) Lunar Planet. Sci. Conf. 42, Abstr. #1660. [13] Martin A.M. et al. (2012) Earth Planet. Sci. Lett. 331-332, 291-304.

  7. Venus-Earth-Mars: comparative climatology and the search for life in the solar system.

    PubMed

    Launius, Roger D

    2012-01-01

    Both Venus and Mars have captured the human imagination during the twentieth century as possible abodes of life. Venus had long enchanted humans-all the more so after astronomers realized it was shrouded in a mysterious cloak of clouds permanently hiding the surface from view. It was also the closest planet to Earth, with nearly the same size and surface gravity. These attributes brought myriad speculations about the nature of Venus, its climate, and the possibility of life existing there in some form. Mars also harbored interest as a place where life had or might still exist. Seasonal changes on Mars were interpreted as due to the possible spread and retreat of ice caps and lichen-like vegetation. A core element of this belief rested with the climatology of these two planets, as observed by astronomers, but these ideas were significantly altered, if not dashed during the space age. Missions to Venus and Mars revealed strikingly different worlds. The high temperatures and pressures found on Venus supported a "runaway greenhouse theory," and Mars harbored an apparently lifeless landscape similar to the surface of the Moon. While hopes for Venus as an abode of life ended, the search for evidence of past life on Mars, possibly microbial, remains a central theme in space exploration. This survey explores the evolution of thinking about the climates of Venus and Mars as life-support systems, in comparison to Earth. PMID:25371106

  8. Venus-Earth-Mars: Comparative Climatology and the Search for Life in the Solar System

    PubMed Central

    Launius, Roger D.

    2012-01-01

    Both Venus and Mars have captured the human imagination during the twentieth century as possible abodes of life. Venus had long enchanted humans—all the more so after astronomers realized it was shrouded in a mysterious cloak of clouds permanently hiding the surface from view. It was also the closest planet to Earth, with nearly the same size and surface gravity. These attributes brought myriad speculations about the nature of Venus, its climate, and the possibility of life existing there in some form. Mars also harbored interest as a place where life had or might still exist. Seasonal changes on Mars were interpreted as due to the possible spread and retreat of ice caps and lichen-like vegetation. A core element of this belief rested with the climatology of these two planets, as observed by astronomers, but these ideas were significantly altered, if not dashed during the space age. Missions to Venus and Mars revealed strikingly different worlds. The high temperatures and pressures found on Venus supported a “runaway greenhouse theory,” and Mars harbored an apparently lifeless landscape similar to the surface of the Moon. While hopes for Venus as an abode of life ended, the search for evidence of past life on Mars, possibly microbial, remains a central theme in space exploration. This survey explores the evolution of thinking about the climates of Venus and Mars as life-support systems, in comparison to Earth. PMID:25371106

  9. Venus-Earth-Mars: Comparative Climatology and the Search for Life in the Solar System

    NASA Astrophysics Data System (ADS)

    Launius, Roger D.

    2012-09-01

    Both Venus and Mars have captured the human imagination during the twentieth century as possible abodes of life. Venus had long enchanted humans - all the more so after astronomers realized it was shrouded in a mysterious cloak of clouds permanently hiding the surface from view. It was also the closest planet to Earth, with nearly the same size and surface gravity. These attributes brought myriad speculations about the nature of Venus, its climate, and the possibility of life existing there in some form. Mars also harbored interest as a place where life had or might still exist. Seasonal changes on Mars were interpreted as due to the possible spread and retreat of ice caps and lichen-like vegetation. A core element of this belief rested with the climatology of these two planets, as observed by astronomers, but these ideas were significantly altered, if not dashed during the space age. Missions to Venus and Mars revealed strikingly different worlds. The high temperatures and pressures found on Venus supported a "runaway greenhouse theory," and Mars harbored an apparently lifeless landscape similar to the surface of the Moon. While hopes for Venus as an abode of life ended, the search for evidence of past life on Mars, possibly microbial, remains a central theme in space exploration. This survey explores the evolution of thinking about the climates of Venus and Mars as life-support systems, in comparison to Earth.

  10. Venus Exploration Goals, Objectives, Investigations, and Priorities: 2007

    E-print Network

    Atreya, Sushil

    Venus Exploration Goals, Objectives, Investigations, and Priorities: 2007 A Report of the Venus input for planning and prioritizing Venus exploration for the next few decades. VEXAG is chartered scientists and engineers, regularly evaluates Venus exploration goals, objectives, investigations

  11. Hinode SOT Plate Scale Reinvestigated by G-Band Images on the 2012 Transit of Venus

    NASA Astrophysics Data System (ADS)

    Kanao, M.; Shimizu, T.; Imamura, T.; Nakamura, M.

    2015-05-01

    The Hinode Solar Optical Telescope (SOT) successfully observed the transit of Venus with an unprecedented high spatial resolution on 5 - 6 June 2012, providing images of the aureole refracted by the atmosphere of Venus and the dark Venus disk against the bright solar surface. The transit of Venus provided a unique opportunity for calibrating the plate scale of SOT images. With the examination of the radius of the dark Venus disk, we determined the plate scale of G-band 430.5 nm images with high accuracy: 0.05369±0.00005 arcsec pixel-1. The radius was defined at the intensity level of the 0.5 transmittance and compared with the angular radius of Venus including the thickness of the atmosphere determined with the measurements of SPICAV onboard Venus Express. Thanks to the high spatial resolution, SOT images show that the dark Venus can be well represented by an ellipse. We observed 7.6 km difference in altitude between the equator and the polar regions.

  12. Recent hotspot volcanism on Venus from VIRTIS emissivity data.

    PubMed

    Smrekar, Suzanne E; Stofan, Ellen R; Mueller, Nils; Treiman, Allan; Elkins-Tanton, Linda; Helbert, Joern; Piccioni, Giuseppe; Drossart, Pierre

    2010-04-30

    The questions of whether Venus is geologically active and how the planet has resurfaced over the past billion years have major implications for interior dynamics and climate change. Nine "hotspots"--areas analogous to Hawaii, with volcanism, broad topographic rises, and large positive gravity anomalies suggesting mantle plumes at depth--have been identified as possibly active. This study used variations in the thermal emissivity of the surface observed by the Visible and Infrared Thermal Imaging Spectrometer on the European Space Agency's Venus Express spacecraft to identify compositional differences in lava flows at three hotspots. The anomalies are interpreted as a lack of surface weathering. We estimate the flows to be younger than 2.5 million years and probably much younger, about 250,000 years or less, indicating that Venus is actively resurfacing. PMID:20378775

  13. Venus nighttime hydrogen bulge

    NASA Technical Reports Server (NTRS)

    Brinton, H. C.; Taylor, H. A., Jr.; Niemann, H. B.; Mayr, H. G.; Nagy, A. F.; Cravens, T. E.; Strobel, D. F.

    1980-01-01

    The concentration of atomic hydrogen in the Venus thermosphere near 165 km altitude and approximately 18 deg north latitude has been derived from Pioneer Venus in situ measurements of H(+), O(+), O and CO2 concentrations, under the assumption of chemical equilibrium. Altitude profiles of derived H concentration suggest that chemical equilibrium prevails to an altitude of at least 200 km on the dayside and to 165 km on the nightside. Measurements below these limits were made by the ion and neutral mass spectrometers on the orbiter spacecraft between December 1978 and July 1979, while periapsis traversed a complete diurnal cycle. The hydrogen concentration is found to rise sharply at both terminators from a dayside value of approximately 50,000/cu cm, and to exhibit an asymmetric nightside distribution with a peak density in the predawn sector approximately 400 times greater than the dayside value. Analysis suggests that wind-induced diffusion, combined with exospheric return flow, can account for the observed hydrogen behavior. The large day-night temperature contrast enhances advective transport, which produces the large H concentration diurnal variation; the shift of the H concentration nighttime maximum toward dawn is caused by atmospheric superrotation.

  14. Progress report on VENUS

    SciTech Connect

    Leitner, Matthaeus A.; Leitner, Daniela; Abbott, Steve R.; Taylor, Clyde E.; Lyneis, Claude

    2002-09-03

    The construction of VENUS, a next generation superconducting Electron Cyclotron Resonance ion source designed to operate at 28 GHz, is complete. The cryostat including the superconducting magnet assembly was delivered in September 2001. During acceptance tests, the superconducting magnets produced an axial magnetic field strength of 4T at injection, 3T at extraction, and a radial field strength of 2T at the plasma chamber wall without any quenches. These fields are sufficient for optimum operation at 28 GHz. The cryogenic system for VENUS has been designed to operate at 4.2 K with two cryocoolers each providing up to 45 W of cooling at 50 K and 1.5 W at 4 K in a closed loop mode without further helium transfers. However, during the acceptance tests an excessive heat leak of about 3W was measured. In addition, the liquid helium heat exchanger did not work properly and had to be redesigned. The cryogenic system modifications will be described. In addition, an update on the installation of the ion source and its beam line components will be given.

  15. Venus Data Analysis Program: Directory of Research Projects (1993-1994)

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This directory provides information about the scientific investigations funded by the NASA Venus Data Analysis Program (VDAP) during fiscal year 1993. The VDAP Directory consists of summary sheets from the proposals that were selected by NASA for funding in FY 93. Each summary sheet indicates the title, principal investigator, institution of the investigation, and information related to the objectives of the research activities proposed for FY 93. The objective of the VDAP Program is to advance our understanding of the nature and evolution of Venus. VDAP supports scientific investigation using data obtained from the Magellan, Pioneer Venus, and other Venus missions, as well as earth-based observations that contribute to understanding the physical and evolutionary properties of Venus. The program intends to enhance the scientific return from these missions by broadening the participation in the analysis of Venus data. Categories of research funded by VDAP are atmosphere, ionosphere, geology, geophysics, and mapping. The directory is intended to provide the science community with an overview of the research projects supported by this program. Research activities identified in this directory were selected for funding in FY 93 on the basis of scientific peer review conducted by the VDAP Review Panel.

  16. Storms on Venus: Lightning-induced chemistry and predicted products

    NASA Astrophysics Data System (ADS)

    Delitsky, M. L.; Baines, K. H.

    2015-08-01

    Observations by many spacecraft that have visited Venus over the last 40 years appear to confirm the presence of lightning storms in the Venus atmosphere. Recent observations by Venus Express indicate that lightning frequency and power is similar to that on Earth. While storms are occurring, energy deposition by lightning into Venus atmospheric constituents will immediately dissociate molecules into atoms, ions and plasma from the high temperatures in the lightning column (>30,000 K) and the associated shock waves and heating, after which these atom and ion fragments of C,O,S,N,H-containing molecules will recombine during cooldown to form new sets of molecules. Spark and discharge experiments in the literature suggest that lightning effects on the main atmospheric molecules CO2, N2, SO2, H2SO4 and H2O will yield carbon oxides and suboxides (COm, CnOm), sulfur oxides (SnO, SnOm), oxygen (O2), elemental sulfur (Sn), nitrogen oxides (NO, N2O, NO2), sulfuric acid clusters (HnSmOx-.aHnSmOx e.g. HSO4-.mH2SO4), polysulfur oxides, carbon soot and other exotic species. While the amounts generated in lightning storms would be much less than that derived from photochemistry, during storms these species can build up in a small area and so their local concentrations may increase significantly. For a storm of 100×100 km, the increase could be ~5 orders of magnitude if they remain in the storm region for a period before becoming well-mixed. Some of these molecular species may be detectable by instruments onboard Venus Express while they are concentrated in the storm regions. We explore the diversity of new products likely created in lightning storms on Venus.

  17. The International VEGA "Venus-Halley" (1984-1986) Experiment: Description and Scientific Objectives

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Venus-Halley (Vega) project will provide a unique opportunity to combine a mission over Venus with a transfer flight to Halley's comet. This project is based on three research goals: (1) to study the surface of Venus; (2) to study the air circulation on Venus and its meteorological parameters; and (3) to study Halley's comet. The objective of the study of Halley's comet is to: determine the physical characteristics of its nucleus; define the structure and dynamics of the coma around the nucleus; define the gas composition near the nucleus; investigate the dust particle distribution as a function of mass at various distances from the nucleus; and investigate the solar wind interaction with the atmosphere and ionosphere of the comet.

  18. The Pioneer Venus Orbiter: 11 years of data. A laboratory for atmospheres seminar talk

    NASA Technical Reports Server (NTRS)

    Kasprzak, W. T.

    1990-01-01

    The Pioneer Venus Orbiter has been in operation since orbit insertion on December 4, 1978. For the past 11 years, it has been acquiring data in the salient features of the planet, its atmosphere, ionosphere, and interaction with the solar wind. A few of the results of this mission are summarized and their contribution to our general understanding of the planet Venus is discussed. Although Earth and Venus are often called twin planets, they are only superficially similar. Possessing no obvious evidence of plate tectonics, lacking water and an intrinsic magnetic field, and having a hot, dense carbon dioxide atmosphere with sulfuric acid clouds makes Venus a unique object of study by the Orbiter's instruments.

  19. The stability of oxyamphiboles: Existence of Ferric-bearing minerals under the reducing conditions on the surface of Venus

    NASA Technical Reports Server (NTRS)

    Straub, Darcy W.; Burns, Roger G.

    1993-01-01

    An enigma of Venusian mineralogy is the suggestion that Fe(3+)-bearing minerals exist under the reducing conditions of the Venusian atmosphere. Analysis of the spectrophotometric data from the Venera 13 and 14 missions, combined with the laboratory reflectance spectral measurements of oxidized basalts at elevated temperatures, led to the suggestion that metastable hematite might exist on Venus. Heating experiments at 475 C when f(sub O2) approximately 10(exp -24) demonstrated that the hematite to magnetite conversion is rapid indicating metastable hematite is not present on Venus. In addition to hematite, several other ferric oxide and silicate minerals have been proposed to occur on Venus, including laihunite or ferrifayalite, Fe(3+)-bearing tephroite, oxyamphiboles, and oxybiotites. Heating experiments performed on these Fe(3+)-bearing minerals under temperature-f(sub O2) conditions existing on Venus suggest that only oxyamphiboles and oxybiotites may be stable on the surface of Venus.

  20. The abundance of sulfur dioxide below the clouds of Venus

    NASA Technical Reports Server (NTRS)

    Bezard, Bruno; De Bergh, Catherine; Fegley, Bruce; Maillard, Jean-Pierre; Crisp, David; Owen, Tobias; Pollack, James B.; Grinspoon, David

    1993-01-01

    We present a new method for determining the abundance of sulfur dioxide below the clouds of Venus. Absorption by the 3nu3 band of SO2 near 2.45 microns has been detected in high-resolution spectra of the night side of Venus recorded at the Canada-France Hawaii telescope in 1989 and 1991. The inferred SO2 abundance is 130 +/- 40 ppm at all observed locations and pertains to the 35-45 km region. These values are comparable to those measured by the Pioneer Venus and Venera 11/12 entry probes in 1978. This stability stands in contrast to the apparent massive decrease in SO2 observed at the cloud tops since these space missions. These results are consistent with laboratory and modeling studies of the SO2 destruction rates in the lower atmosphere of Venus. The new spectroscopic technique presented here allows a remote monitoring of the SO2 abundance below the clouds, a likely tracer of Venusian volcanism.

  1. Geologic Map of the Helen Planitia Quadrangle (V-52), Venus

    USGS Publications Warehouse

    Lopez, Ivan; Hansen, Vicki L.

    2008-01-01

    The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphere on October 12, 1994. Magellan Mission objectives included (1) improving the knowledge of the geological processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving the knowledge of the geophysics of Venus by analysis of Venusian gravity. The Helen Planitia quadrangle (V-52), located in the southern hemisphere of Venus between lat 25 deg S. and 50 deg S. and between long 240 deg E. and 270 deg E., covers approximately 8,000,000 km2. Regionally, the map area is located at the southern limit of an area of enhanced tectonomagmatic activity and extensional deformation, marked by a triangle that has highland apexes at Beta, Atla, and Themis Regiones (BAT anomaly) and is connected by the large extensional belts of Devana, Hecate, and Parga Chasmata. The BAT anomaly covers approximately 20 percent of the Venusian surface.

  2. Descent into theDescent into theDescent into theDescent into the Hell of VenusHell of VenusHell of VenusHell of Venus

    E-print Network

    Alfonseca, Manuel

    Descent into theDescent into theDescent into theDescent into the Hell of VenusHell of VenusHell of VenusHell of Venus Manuel AlfonsecaManuel AlfonsecaManuel AlfonsecaManuel Alfonseca #12;Manuel Alfonseca 2 #12;Descent into the Hell of Venus 3 DESCENT INTO THE HELL OF VENUS Manuel Alfonseca All Rights

  3. Clouds and aerosols on Venus: an overview

    NASA Astrophysics Data System (ADS)

    Titov, D. V.; Ignatiev, N. I.; McGouldrick, K.; Wilquet, V.; Wilson, C. F.

    2014-04-01

    The past decade demonstrated significant progress in understanding of the Venus cloud system. This paper gives a summary of new observations and modelling efforts that will form the basis for a relevant chapter in the Venus III book. Venus Express observations reveal significant latitudinal variations and temporal changes in the global cloud top morphology [1]. The cloud top altitude varies from ~72 km in the low and middle latitudes to ~64 km in the polar region, correlated with decrease of the aerosol scale height from 4 ± 1.6 km to 1.7 ± 2.4 km marking a vast polar depression [2, 3]. UV imaging shows the middle latitudes and polar regions in unprecedented detail. The eye of the Southern polar vortex was found to be a strongly variable feature with complex morphology and dynamics [4]. Solar and stellar occultations give access to a vertical profiling of the light absorption by the aerosols in the upper haze. The aerosol loading in the mesosphere of Venus investigated by SPICAV experiment onboard Venus Express between 2006 and 2010 was highly variable on both short and long time scales. The extinction at a given altitude can vary with a factor of 10 for occultations separated by a few Earth days. The extinction at a given altitude is also significantly lower towards the poles (by a factor 10 at least) compared to the values around the equator, while there is apparently no correlation between the extinction and the latitude in the region comprised between ±40° around the equator [5]. Based on Mie theory and on the observed spectral dependence of light extinction in spectra recorded simultaneously in the UV (SPICAV-UV), in the near IR (SPICAV-IR), and in the short-and midwavelength IR (SPICAV-SOIR), the size distribution of aerosols in the upper haze of Venus was retrieved, assuming H2SO4/water composition of the droplets [6]. The optical model includes H2SO4 concentrations from 60 to 85%. A number of results are strikingly new: (1) an increase of the H2SO4 concentration with a decreasing altitude (from 70-75% at about 90 km to 85% at 70 km of altitude) and (2) Many SOIR/SPICAV data cannot be fitted when using size distributions found in the literature, with an effective radius below 0.3 ?m and a variance of about 2. The scale height of the upper haze is found to be 6.9 ± 5.1 km. The lower & middle cloud layers - those at 48 - 60 km altitudes - are difficult to observe, as they are hidden by upper clouds. Nevertheless, both nightside near-IR sounding and radio occultation has provided valuable insight into cloud processes in this region. Near IR sounding reveals the morphology of the lower/middle clouds 'backlit' by thermally emitted photons from the lower atmosphere. The morphology of these clouds changes on timescales of order of 24 hours [7]. The vertically integrated cloud optical depth is twice as great in the polar collar (at 75 degrees latitude) compared to low latitudes. Spectral band ratio analysis, if interpreted strictly in terms of Mode 1 / 2 / 2' / 3 particles of H2SO4:H2O mixtures, the acidity of the cloud particles is found to be higher near the polar collar and in regions of optically thick cloud [8]. Particles in the centre of the polar vortex exhibit anomalously high band ratios so are significantly larger and/or of different composition than those at low latitudes [9]. Radio occultation from Venus Express confirms that the atmosphere is in convective equilibrium from 50-60 km [10]. Sulphuric acid vapour profiles calculated from the absorption of the radio signals show an atmosphere saturated with sulphuric acid in the cloud layer [11]. Both of these results are consistent with the understanding of convective condensational cloud at altitudes of 50-60 km. Microphysical simulations of the aerosol populations in the atmosphere of Venus have received a boost from the recent exploration of particle properties carried out by various teams using Venus Express over the last decade or so. Numerous groups are applying separate models to the coupled problems of the Venus clouds. Quasi-periodic variabilit

  4. Earth, Venus and Planetary Diversity

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.

    2015-05-01

    To what extent are planets diverse in internal structure and behavior even when their outward characteristics (e.g., mass and radius) are similar? I will argue that diversity is expected and that Earth and Venus differences illustrate this.

  5. Laying bare Venus' dark secrets

    SciTech Connect

    Allen, D.A.

    1987-10-01

    Ground-based IR observations of the dark side of Venus obtained in 1983 and 1985 with the Anglo-Australian Telescope are studied. An IR spectrum of Venus' dark side is analyzed. It is observed that the Venus atmosphere is composed of CO and radiation escapes only at 1.74 microns and 2.2 to 2.4 microns. The possible origin of the radiation, either due to absorbed sunlight or escaping thermal radiation, was investigated. These two hypotheses were eliminated, and it is proposed that the clouds of Venus are transparent and the radiation originates from the same stratum as the brighter portions but is weakened by the passage through the upper layer. The significance of the observed dark side markings is discussed.

  6. The study of Venus continues

    NASA Technical Reports Server (NTRS)

    Barsukov, V. L.

    1983-01-01

    The landing of the Soviet interplanetary station Venera-13 in March, 1982, is described. One of the tasks of the station was to study the composition and structure of cloud layers on Venus. It was established that the cloud layer consists largely of sulfuric acid. Data obtained from other Venera stations are also presented. It is concluded that fundamental similarities can be found in the geological development of the Earth and Venus.

  7. The June 6 2012 transit of Venus: Imaging and spectroscopic analysis of the upper atmosphere emission

    NASA Astrophysics Data System (ADS)

    Bazin, C.; Zhi, X.; Valls-Gabaud, D.; Koutchmy, S.; Rocher, P.; Zin, Z. Y.; Fu, Y.; Yang, L.; Liu, G. Q.; Liu, Z.; Ji, K.; Goodarzi, H.

    2014-12-01

    In the context of transiting exoplanets, the last June 6, 2012 Venus transit was a unique opportunity to address important questions regarding its atmosphere. The transit of Venus is indeed a particular case of an Earth-like planet transit, and the inference one can make about the upper layers of its atmosphere can be applied to other exoplanets. To this aim, we designed a small spectrograph that we placed at the focus of the New Vacuum Solar Telescope of Yunnan Observatory in China (45 m focus and 1 m of aperture), coupled to a 4K×2K 14 bit CCD detector, to measure low-resolution optical spectra of the refracted, scattered and transmitted solar radiation in the upper layers of the planet. It covered the 385-780 nm range when Venus was over the disc, and 540-680 nm (including the O_2 terrestrial bands) during the 18 minutes-long egress. The H? and He I D3 lines were recorded repeatedly. The atmospheric Lomonossov arc of Venus was simultaneously imaged using H? and TiO filters, allowing us to check the slit position on the images of Venus and to locate the spectroscopic features on its disc. The spectra show the signature of the Northern Pole horn part; a second part was evidenced on the spectra taken near but outside the limb. We studied the O_2, H_2O and H? line profiles searching for signatures arising from Venus and we compared the observed spectra with synthetic models. The spectroscopic dataset can now be used by a large community for discussing the properties of the upper atmosphere of Venus and the future detection of Venus-like exoplanets. Finally, the study is completed using a unique very high resolution deconvolved image of the arc and Venus silhouetted at the limb of the Sun, from the SOT of the Hinode space mission.

  8. Transits Of Venus: 1639, 1761, 1769, 1874, 1882, 2004, And 2012

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.

    2012-01-01

    Transits of Venus are exceedingly rare predictable astronomical events, with only six having been observed since Jeremiah Horrox corrected Johannes Kepler's Rudolphine Tables and observed the transit of 1639. Edmond Halley's 1716 method of finding the size and scale of the Solar System and thus of the Universe led to hundreds of 18th-century and 19th-century transit-of-Venus expeditions for each event. I discuss the history and importance of the transit observations, and how spacecraft observations of the 1999 transit of Mercury, repeated at the 2003 and 2006 transits, led to the solution of the black-drop effect problem that had prevented Halley's method from reaching its desired accuracy and thus solution of the noble problem of astronomy to find the size and scale of the solar system. Other spacecraft observations of the 2004 transit of Venus have led to an analysis of how Venus's atmosphere becomes visible for about 25 minutes before second contact and after third contact, and links with prior historical claims, mostly invalid, to have discovered Venus's atmosphere at transits. Total-solar-irradiance spacecraft observations at the 2004 Venus transit link to exoplanet discoveries with NASA's aptly named Kepler Mission and ESA's CoRoT. I further link previous transit observations to planned observations for the June 5/6, 2012, Venus transit and the May 9, 2016, Mercury transit, together providing a historical basis for 22nd-century astronomers preparing to observe the December 10, 2117, Venus transit. My observations at the 2004 and 2012 transits of Venus were and will be supported in large part by grants from the Committee for Research and Exploration of the National Geographic Society. My solar observations were supported in part by NASA grant NNG04GK44G for work with the TRACE spacecraft and NASA Marshall grant NNX10AK47A and planetary work supported in part by NNX08AO50G from NASA Planetary Astronomy.

  9. A Venus Rover Capable of Long Life Surface Operations

    NASA Astrophysics Data System (ADS)

    Evans, M.; Shirley, J. H.; Abelson, R. D.

    2005-12-01

    Access to the surface of Venus would allow planetary scientists to address a number of currently open questions. Among these are the elemental and mineralogical composition of the surface; the interaction of the surface with the atmosphere; the atmospheric composition, especially isotope ratios of key species; the nature of the planetary volcanism (present activity, emissions to the atmosphere, and composition); planetary seismicity; the local surface meteorology (winds and pressure variability); and the surface geology and morphology at particular locations on the surface. A long lived Venus rover mission could be enabled by utilizing a novel Stirling engine system for both cooling and electric power. Previous missions to the Venus surface, including the Pioneer Venus and Venera missions, survived for only a few hours. The rover concept described in the present study is designed for a surface lifetime of 60 days, with the potential of operating well beyond that. A Thermo-Acoustic Stirling Heat Engine (TASHE) would convert the high-temperature (~1200 °C) heat from General Purpose Heat Source (GPHS) modules into acoustic power which then drives a linear alternator and a pulse tube cooler to provide electric power and remove the large environmental heat load. The "cold" side of the engine would be furnished by the ambient atmosphere at 460 °C. This short study focused on the feasibility of using the TASHE system in this hostile environment to power a ~650 kg rover that would provide a mobile platform for science measurements. The instrument suite would collect data on atmospheric and surface composition, surface stratigraphy, and subsurface structure. An Earth-Venus-Venus trajectory would be used to deliver the rover to a low entry angle allowing an inflated ballute to provide a low deceleration and low heat descent to the surface. All rover systems would be housed in a pressure vessel in vacuum with the internal temperature maintained by the TASHE below 50 °C. No externally deployed or articulated components would be used and penetrations through the pressure vessel are minimized. Science data would be returned direct to Earth using S-Band to minimize atmospheric attenuation.

  10. Crustal deformation: Earth vs Venus

    NASA Technical Reports Server (NTRS)

    Turcotte, D. L.

    1989-01-01

    It is timely to consider the possible tectonic regimes on Venus both in terms of what is known about Venus and in terms of deformation mechanisms operative on the earth. Plate tectonic phenomena dominate tectonics on the earth. Horizontal displacements are associated with the creation of new crust at ridges and destruction of crust at trenches. The presence of plate tectonics on Venus is debated, but there is certainly no evidence for the trenches associated with subduction on the earth. An essential question is what kind of tectonics can be expected if there is no plate tectonics on Venus. Mars and the Moon are reference examples. Volcanic constructs appear to play a dominant role on Mars but their role on Venus is not clear. On single plate planets and satellites, tectonic structures are often associated with thermal stresses. Cooling of a planet leads to thermal contraction and surface compressive features. Delamination has been propsed for Venus by several authors. Delamination is associated with the subduction of the mantle lithosphere and possibly the lower crust but not the upper crust. The surface manifestations of delamination are unclear. There is some evidence that delamination is occurring beneath the Transverse Ranges in California. Delamination will certainly lead to lithospheric thinning and is likely to lead to uplift and crustal thinning.

  11. Spatial and temporal variations of Venus haze properties obtained from Pioneer Venus Orbiter polarimetry

    E-print Network

    Spatial and temporal variations of Venus haze properties obtained from Pioneer Venus Orbiter. [1] The spatial and temporal variations of the polarization of light scattered by Venus, as observed by the Pioneer Venus Orbiter between 1978 and 1990, is analyzed in terms of spatial and temporal variations

  12. Hot-spot tectonics of Eistla Regio, Venus: Results from Magellan images and Pioneer Venus gravity

    NASA Technical Reports Server (NTRS)

    Grimm, Robert E.; Phillips, Roger J.

    1991-01-01

    Eistla Regio (ER) is a broad, low, discontinuous topographic rise striking roughly EW at low northern latitudes of Venus. Some 2000 x 7000 km in dimensions, it is the third largest rise in planform on Venus after Aphrodite Terra and Beta Phoebe Regiones. These rises are the key physiographic elements in a hot spot model of global tectonics including transient plume behavior. Since ER is the first such rise viewed by Magellan and the latitude is very favorable for Pioneer Venus gravity studies, some of the predictions of a time dependent hot spot model are tested. Western ER is defined as the rise including Gula and Sif Mons and central ER as that including Sappho Patera. Superior conjunction prevented Magellan from returning data on eastern ER (Pavlova) during the first mapping cycle. It is concluded that the western and central portions of ER, while part of the same broad topographic rise and tectonic framework, have distinctly different surface ages and gravity signatures. The western rise, including Gula and Sif Mons, is the expression of deep seated uplift with volcanism limited to the individual large shields. The eastern portion has been widely resurfaced more recently by thermal anomalies in the mantle.

  13. Imaging of Mercury and Venus from a flyby

    USGS Publications Warehouse

    Murray, B.C.; Belton, M.J.S.; Edward, Danielson G.; Davies, M.E.; Kuiper, G.P.; O'Leary, B. T.; Suomi, V.E.; Trask, N.J.

    1971-01-01

    This paper describes the results of study of an imaging experiment planned for the 1973 Mariner Venus/Mercury flyby mission. Scientific objectives, mission constraints, analysis of alternative systems, and the rationale for final choice are presented. Severe financial constraints ruled out the best technical alternative for flyby imaging, a film/readout system, or even significant re-design of previous Mariner vidicon camera/tape recorder systems. The final selection was a vidicon camera quite similar to that used for Mariner Mars 1971, but with the capability of real time transmission during the Venus and Mercury flybys. Real time data return became possible through dramatic increase in the communications bandwidth at only modest sacrifice in the quality of the returned pictures. Two identical long focal length cameras (1500 mm) were selected and it will be possible to return several thousand pictures from both planets at resolutions ranging from equivalent to Earthbased to tenths of a kilometer at encounter. Systematic high resolution ultraviolet photography of Venus is planned after encounter in an attempt to understand the nature of the mysterious ultraviolet markings and their apparent 4- to 5-day rotation period. Full disk coverage in mosaics will produce pictures of both planets similar in quality to Earthbased telescopic pictures of the Moon. The increase of resolution, more than three orders of magnitude, will yield an exciting first look at two planets whose closeup appearance is unknown. ?? 1971.

  14. The effect of dys-1 mutation on miRNA expression profile in Caenorhabditis elegans during Shenzhou-8 mission

    NASA Astrophysics Data System (ADS)

    Xu, Dan; Sun, Yeqing; Gao, Ying; Xing, Yanfang

    microRNAs (miRNAs) is reported to be sensitive to radiation exposure and altered gravity, involved in a variety of biological processes through negative regulation of gene expression. Dystrophin-like dys-1 gene is expressed and required in muscle tissue, which plays a vital role in mechanical transduction when gravity varies. In the present study, we investigated the effect of dys-1 mutation on miRNA expression profile in Caenorhabditis elegans (C. elegans) under space radiation associated with microgravity (R+M) and radiation alone (R) environment during Shenzhou-8 mission. We performed miRNA microarray analysis in dys-1 mutant and wide-type (WT) of dauer larvae and found that 27 miRNAs changed in abundance after spaceflight. Compared with WT, there was different miRNA expression pattern in different treatments in dys-1 mutant. Cel-miR-796 and miR-124 were reversely expressed under R+M and R environment in WT and dys-1 mutant, respectively, indicating they might be affected by microgravity. Mutation of dys-1 remarkably reduced the number of altered miRNAs under space environment, resulting in the decrease of genes in biological categories of “body morphogenesis”, “behavior”, “cell adhesion” and so on. Particularly, we found that those genes controlling regulation of locomotion in WT were lost in dys-1 mutant, while genes in positive regulation of developmental process only existed in dys-1 mutant. miR-796 was predicted to target genes ace-1 and dyc-1 that are functionally linked to dys-1. Integration analysis of miRNA and mRNA expression profile revealed that miR-56 and miR-124 were involved in behavior and locomotion by regulating different target genes under space environment, among which nep-11, deb-1, C07H4.1 and F11H8.2 might be associated with neuromuscular system. Our findings suggest that dys-1 could cause alteration of miRNAs and target genes, involved in regulating the response of C. elegans to space microgravity in neuromuscular system. This research will provide new insight for better understanding of the mechanism in microgravity-induced muscular dystrophy.

  15. Changes in miRNA expression profile of space-flown Caenorhabditis elegans during Shenzhou-8 mission.

    PubMed

    Xu, Dan; Gao, Ying; Huang, Lei; Sun, Yeqing

    2014-04-01

    Recent advances in the field of molecular biology have demonstrated that small non-coding microRNAs (miRNAs) have a broad effect on gene expression networks and play a key role in biological responses to environmental stressors. However, little is known about how space radiation exposure and altered gravity affect miRNA expression. The "International Space Biological Experiments" project was carried out in November 2011 by an international collaboration between China and Germany during the Shenzhou-8 (SZ-8) mission. To study the effects of spaceflight on Caenorhabditis elegans (C. elegans), we explored the expression profile miRNA changes in space-flown C. elegans. Dauer C. elegans larvae were taken by SZ-8 spacecraft and experienced the 16.5-day shuttle spaceflight. We performed miRNA microarray analysis, and the results showed that 23 miRNAs were altered in a complex space environment and different expression patterns were observed in the space synthetic and radiation environments. Most putative target genes of the altered miRNAs in the space synthetic environment were predicted to be involved in developmental processes instead of in the regulation of transcription, and the enrichment of these genes was due to space radiation. Furthermore, integration analysis of the miRNA and mRNA expression profiles confirmed that twelve genes were differently regulated by seven miRNAs. These genes may be involved in embryonic development, reproduction, transcription factor activity, oviposition in a space synthetic environment, positive regulation of growth and body morphogenesis in a space radiation environment. Specifically, we found that cel-miR-52, -55, and -56 of the miR-51 family were sensitive to space environmental stressors and could regulate biological behavioural responses and neprilysin activity through the different isoforms of T01C4.1 and F18A12.8. These findings suggest that C. elegans responded to spaceflight by altering the expression of miRNAs and some target genes that function in diverse regulatory pathways. PMID:26432588

  16. Critical components of Venus Lower and Upper atmospheres with FirefOx and Venus Neutron Spectrometer (VeNuS)

    NASA Astrophysics Data System (ADS)

    Izenberg, N. R.; Papadakis, S. J.; Monica, A. H.; Deglau, D. M.; Lawrence, D. J.; Peplowski, P. N.

    2015-10-01

    We present two instrument concepts for understanding critical aspects of Venus' upper and lower atmosphere. FirefOx is an oxygen fugacity sensor for the lower atmosphere, and The Venus Nuclear Spectrometer (VeNuS) studies composition and volcanic activity signals in the upper atmosphere.

  17. Clouds and aerosols on Venus: an overview

    NASA Astrophysics Data System (ADS)

    Titov, Dmitri; Ignatiev, Nikolay; McGouldrick, Kevin; Wilquet, Valerie; Wilson, Colin

    2015-04-01

    The past decade demonstrated significant progress in understanding of the Venus cloud system. Venus Express observations revealed significant latitudinal variations and temporal changes in the global cloud top morphology. The cloud top altitude varies from ~72 km in the low and middle latitudes to ~64 km in the polar region, correlated with decrease of the aerosol scale height from 4 ± 1.6 km to 1.7 ± 2.4 km marking a vast polar depression. The UV imaging shows the middle latitudes and polar regions in unprecedented detail. The eye of the Southern polar vortex was found to be a strongly variable feature with complex morphology and dynamics. Solar and stellar occultations give access to a vertical profiling of the light absorption by the aerosols in the upper haze. The aerosol loading in the mesosphere of Venus investigated by SPICAV experiment onboard Venus Express between 2006 and 2010 was highly variable on both short and long time scales. The extinction at a given altitude can vary with a factor of 10 for occultations separated by a few Earth days. The extinction at a given altitude is also significantly lower towards the poles (by a factor 10 at least) compared to the values around the equator, while there is apparently no correlation between the extinction and the latitude in the region comprised between ±40° around the equator. Based on the Mie theory and on the observed spectral dependence of light extinction in spectra recorded simultaneously in the UV (SPICAV-UV), in the near IR (SPICAV-IR), and in the short-and mid-wavelength IR (SPICAV-SOIR), the size distribution of aerosols in the upper haze of Venus was retrieved, assuming H2SO4/water composition of the droplets. The optical model includes H2SO4 concentrations from 60% to 85%. A number of results are strikingly new: (1) an increase of the H2SO4 concentration with a decreasing altitude (from 70-75% at about 90 km to 85% at 70 km of altitude) and (2) Many SOIR/SPICAV data cannot be fitted when using size distributions found in the literature, with an effective radius below 0.3 ?m and a variance of about 2. The scale height of the upper haze is found to be 6.9 ± 5.1 km. The lower and middle cloud layers - those at 48 - 60 km altitudes - are difficult to observe, as they are hidden by upper clouds. Nevertheless, both nightside near-IR sounding and radio occultation has provided valuable insight into cloud processes in this region. Near IR sounding reveals the morphology of the lower/middle clouds 'backlit' by thermally emitted photons from the lower atmosphere. The morphology of these clouds changes on timescales of order of 24 hours. The vertically integrated cloud optical depth is twice as great in the polar collar (at 75 degrees latitude) compared to low latitudes. Spectral band ratio analysis, if interpreted strictly in terms of Mode 1 / 2 / 2' / 3 particles of H2SO4:H2O mixtures, suggests that the acidity of the cloud particles is higher near the polar collar and in regions of optically thick cloud. Particles in the centre of the polar vortex exhibit anomalously high band ratios so are significantly larger and/or of different composition than those at low latitudes. Radio occultation from Venus Express confirms that the atmosphere is in convective equilibrium from 50-60 km. Sulphuric acid vapour profiles calculated from the absorption of the radio signals show an atmosphere saturated with sulphuric acid in the cloud layer. Both of these results are consistent with the understanding of convective condensational cloud at altitudes of 50-60 km. Microphysical simulations of the aerosol populations in the atmosphere of Venus have received a boost from the recent exploration of particle properties carried out by various teams using Venus Express over the last decade or so. Numerous groups are applying separate models to the coupled problems of the Venus clouds. Quasi-periodic variability of aerosol population properties has been found in model simulations by several groups under both forced and unforced conditions. Since the clouds play such a significant

  18. Mars Human Exploration Reference Mission

    NASA Technical Reports Server (NTRS)

    Drake, Bret

    1998-01-01

    This presentation proposes the next steps for human exploration of Mars. The presentation reviews the reasons for human exploration of Mars. Two different trajectories are proposed: (1) for a long stay mission, and (2) for a short term mission, which could also include a swing by Venus. A reference mission scenario is investigated, which includes forward deployment of two cargo missions, followed by a human piloted mission. The power needs of such a mission include nuclear thermal propulsion, and the possible use of Mars in situ resources. The exploration will require electric propulsion, stationary power source, and a mobile power source. The trajectories required for electric propulsion of earth are shown, and the engineering of a Mars Transportation Habitat are reviewed.

  19. Pioneer Venus large probe neutral mass spectrometer

    NASA Technical Reports Server (NTRS)

    Hoffman, J.

    1982-01-01

    The deuterium hydrogen abundance ratio in the Venus atmosphere was measured while the inlets to the Pioneer Venus large probe mass spectrometer were coated with sulfuric acid from Venus' clouds. The ratio is (1.6 + or - 0.2) x 10 to the minus two power. It was found that the 100 fold enrichment of deuterium means that Venus outgassed at least 0.3% of a terrestrial ocean and possibly more.

  20. First observations of VIRTIS at Venus

    NASA Astrophysics Data System (ADS)

    Drossart, P.; Piccioni, G.; Virtis/Venus Express Team

    After the orbit insertion of Venus Express on 2006, April 11, VIRTIS observations have taken place during the Venus Orbit Insertion (VOI), followed by a commissioning phase and the first science orbits. After verification of the instrument performances and calibration phase, first science observations have begun. A description of the observations during the first 43 orbits will be given. VIRTIS is a three channel instrument (ESA-SP in press): VIRTIS-M-vis (imaging spectrometry from 0.3 to 1 micron), VIRTIS-M-IR (imaging spectrometry from 1 to 5 micron) and VIRTIS-H (high spectral resolution channel from 2 to 5 micron), working usually in parallel. A combined observation through the three channels have provided the following results: • The first direct observations of the South Polar Vortex, which mirrors the observations of the North Polar Vortex observed by Pioneer Venus (Taylor et al., JGR, 1980). Observations at different wavelengths in thermal emission show a complex horizontal and vertical structure. • Dynamical measurements of the deep cloud structure from thermal emission (night side), at a global scale from South pole to Equator. • The detection of large fluorescent emission in CO2 at 4.3 micron (day side), with prominent peak at the limb and substantial emission in nadir viewing. • An accurate measurement of the CO latitudinal profile from night side observations, with a maximum at ˜60dg South latitude, confirming with a higher accuracy the pioneer observations made by Galileo / NIMS in 1990 (Collard et al, PSS, 1993). • A measurement of the atmospheric composition at 30 km from night side observations at 2.3 micron. • Observations of CO at 2.3 micron (day side), above the cloud level. • The detection and the mapping of the surface in the infrared windows on the night side at 1-1.18 micron. Future observations will focus on dynamics, structure and composition.

  1. Latest results of the LMD Venus GCM

    NASA Astrophysics Data System (ADS)

    Lebonnois, S.; Marcq, E.; Lott, F.

    2012-12-01

    The LMD Venus General Circulation Model (GCM), under development since 2005, models the circulation in Venus atmosphere (from the surface up to roughly 100 km), in particular the superrotation feature. The temperature structure is computed using a specific radiative transfer module based on net-exchange matrix formulation. Since the publication of the GCM details (Lebonnois et al, JGR 115, 2010, doi:10.1029/2009JE003458), some improvements were done, especially for the boundary layer scheme that affects the exchange of angular momentum between atmosphere and surface. Surprising impact of initial conditions on the steady-state zonal winds is also discussed. Passive tracers, tuned to mimic CO and OCS distributions, have also been added to the model to simulate the latitudinal distributions induced by transport. In this presentation, comparisons between our latest simulations and available observations from Venus Express (winds, temperature fields, CO and OCS distributions) are detailed: zonal and meridional wind distributions in the cloud region and above, thermal tide features in winds and temperature near the cloud-top, CO and OCS latitudinal profiles below the clouds. These comparisons help constrain the meridional circulation and its impact on trace species distributions, the chemical relaxation timescale of the same trace species as well as the thermal tides and their role in the angular momentum budget and in the superrotation mechanism. The impact on the zonal wind field of gravity waves that may be generated near the surface is currently investigated with a new parametrisation. These gravity waves have been suggested as a significant contributor in the angular momentum budget and superrotation mechanism (Hou and Farrell, J. Atmos. Sci. 44, pp.1049-1061, 1987, doi:10.1175/1520-0469(1987)044<1049:SIBCLA>2.0.CO;2). This parametrisation and its first results are presented here.

  2. Earth and Venus transmission spectra during transit

    E-print Network

    Widemann, Thomas

    Earth and Venus transmission spectra during transit 3rd Europlanet workshop ­ 4th PHC/Sakura meeting: Venus as a transiting exoplanet March 5 ­ 7 2012, Paris, France A. García Muñoz (Formerly at) Instituto de Astrofísica de Canarias, La Laguna, Spain Frank P. Mills (Venus work) The Australian National

  3. Goals, Objectives, and Investigations for Venus Exploration

    E-print Network

    Rathbun, Julie A.

    Goals, Objectives, and Investigations for Venus Exploration May 2014 #12; ii Goals, Objectives, and Investigations for Venus Exploration At the VEXAG meeting in November 2012, it was resolved to update the scientific priorities and strategies for Venus exploration. To achieve this goal, three major

  4. LIPs on Venus Vicki L. Hansen

    E-print Network

    Hansen, Vicki

    LIPs on Venus Vicki L. Hansen Department of Geological Sciences, University of Minnesota Duluth, Duluth MN 55812, United States Accepted 22 January 2007 Abstract Venus, a planet similar to Earth in heat processes, including regions large enough to be considered LIPs. Thus Venus provides an excellent

  5. Atmospheric evolution on Venus Bruce Fegley, Jr.

    E-print Network

    for and against both models (Lewis and Prinn, 1984; Yung and DeMore, 1999). Atmospheric evolution on Venus has1 Atmospheric evolution on Venus Bruce Fegley, Jr. Planetary Chemistry Laboratory Department and Ancient Environments Edited by Vivien Gornitz January 2004 #12;2 ATMOSPHERIC EVOLUTION ON VENUS Overview

  6. Investigating the Geophysics of Venus: Result of the post-Alpbach Summer School 2014

    NASA Astrophysics Data System (ADS)

    Koopmans, Robert-Jan; ?osiak, Anna; Bia?ek, Agata; Donohoe, Anthony; Fernández Jiménez, María; Frasl, Barbara; Gurciullo, Antonio; Kleinschneider, Andreas; Mannel, Thurid; Muñoz Elorza, Iñigo; Nilsson, Daniel; Oliveira, Marta; Sørensen-Clark, Paul; Timoney, Ryan; van Zelst, Iris

    2015-04-01

    Venus has been investigated by only five dedicated mission programs since the beginning of space flight. This relatively low level of interest is remarkable when considering that mass and radius of Venus are very similar to Earth's, while at the same time characteristics such as spin rate, atmospheric composition, pressure and temperature, make Venus a very different, inhabitable world. The underlying causes of these differences are not well understood. Apprehending Venus' tectonics and internal structure would not only shed light on the question why those two planets evolved so differently, but also help refining current models of planetary systems formation. In order to answer the question about reasons for differences in evolution of those two planets a group of 15 young scientists and engineers designed a mission to Venus during a follow-up of the Alpbach Summer School 2014. The primary objective of this mission is to learn whether Venus is tectonically active and on what time scale. In order to accomplish this goal the mission will determine the crustal structure of Venus, the current activity and distribution of active volcanoes and the movement of continental plates. The secondary objective is to further constrain the models of Venus' internal structure and composition. To achieve this, the mission will investigate the size, state and composition of the core as well as the state and composition of the mantle. The proposed mission consists of an orbiter in a near-polar circular orbit around Venus and a balloon for in-situ measurements operating during the initial phase of the mission. The balloon carries a nephelometer, a magnetometer, a mass spectrometer and stereo microphones and meteorological package. The orbiter carries a gradiometer for determining the gravity field, a synthetic aperture radar for investigating small changes in surface topography and mapping microwave signals from the surface and an IR and UV spectrometer and IR camera for monitoring heat signatures from volcanoes. By using the previous landers as reference points it will also be possible to accurately determine the spin rate with the radar. The nominal mission duration is planned to be five years starting from the release of the balloon. The balloon will operate for 25 days during which it oscillates vertically in the atmosphere between an altitude of 40 and 60 kilometres in a period of about six hours. At the same time, due to prevailing wind directions on Venus, it will gradually spiral from the equator towards higher latitudes. During the balloon science phase the orbiter will be in an elliptical orbit to maximise the time of visibility of the balloon with the orbiter. After this phase, the orbiter will be brought into a circular orbit at an altitude of 250 kilometres. To save fuel, apoapsis lowering will be achieved by aerobreaking in Venus' atmosphere. In the presentation further details about the mission timeline will be given. Particular engineering problems such as thermal control and data communication and the proposed solutions will be presented.

  7. Exploring the interior structure of Venus with balloons and satellites

    NASA Astrophysics Data System (ADS)

    Mimoun, David; Cutts, Jim; Stevenson, Dave

    2015-04-01

    Although present daily in our sky as the brightest object at dusk and dawn, many characteristics of Venus remains a mystery. Its dense atmosphere hides the surface from orbital viewing, and the extreme conditions experienced at its surface (460°C, almost 100 bar of pressure at the surface) pose a formidable challenge to the sustained survival and operation of planetary landers. Despite their sharply contrasting atmospheres, Venus is not very different from Earth in size, its composition should be very similar, its orbit is very close to be circular and it is only a little closer to the Sun ( 0.7 A.U). So what are the processes that turned the twin sister of our planet into such a different object? And how can we better understand the processes that have shaped the terrestrial planets, and to understand their formation history? With its harsh surface environment, conventional seismology on Venus, requiring seismometers to be deployed at the surface for months or even years seems impractical. In June 2014, the Keck Institute for Space Studies (KISS) at the California Institute of Technology sponsored a one-week workshop with 30 specialists in the key techniques and technologies relevant to investigating Venus's interior structure focusing on alternative approaches to seismology . As the vertical component of surface motion on Venus is very efficiently coupled into the atmosphere as infrasonic waves, especially at low frequency, several alternative approaches to detecting seismic events can be considered. Seismo-acoustic waves propagate upwards producing pressure fluctuations in the middle atmosphere of Venus and the seismic wave energy is ultimately dissipated by local heating, ionospheric perturbation, or airglow. These atmospheric perturbations can therefore be recorded either in-situ (with a barometer network, deployed on balloons floating in the cloud layer near 55 km) or remotely via optical imaging or electromagnetic sounding deployed on a spacecraft. A report, describing the findings of a workshop, sponsored by the Keck Institute of Space Studies (KISS), concludes that seismic investigations can be successfully conducted from all three vantage points - surface, middle atmosphere and space; these three vantage points being complementary in the information they provide. These novel techniques open a new window for the exploration of the interior structure of Venus, and enables a roadmap leading to a dedicated geophysical mission to our sister planet.

  8. Variability of CO, OCS And H2O Below The Clouds of Venus From VIRTIS-HNight-side Spectra

    NASA Astrophysics Data System (ADS)

    Marcq, Emmanuel; Bezard, B.; Drossart, P.; Piccioni, G.; VIRTIS Team

    2007-10-01

    The VIRTIS imaging spectrometer has provided numerous spectra of Venus since the beginning of the Venus Express mission in April 2006. The high resolution of the H-channel (R 2000) enables the investigation of the composition below the clouds using the thermal emission from the night side of the planet, since several absorption of minor components (CO, OCS, H2O, HDO, SO2, HF) are located in the 2.3 µm transparency window of CO2. Using a radiative transfer computer model, we were able to derive constraints on the vertical profiles of CO, OCS and H2O in the 30-40 km altitude range up to areas unreacheable with Earth-based instruments (0° - 60°S). Our findings extend the latitudinal trends already noticed from both space (Collard et al., 1993, using Galileo/NIMS) and Earth (Marcq et al. 2005,2006, using IRTF/SpeX): an increase of CO towards high latitudes (30 ± 10 % between 60°S and 0°), a correlated decrease of OCS in the same region and a constant abundance of 28 ± 4 ppmv at 35 km for H2O. The latitudinal variations of CO are in good agreement with the VIRTIS-M observations from Tsang et al. (private communication). The quantitative interpretation of CO and OCS variations in terms of global-scale vertical circulation is in progress, using circulation models such as Yung et al's (private communication) in 2D and Lebonnois et al.'s (38th DPS meeting, #19.04) in 3D, thus helping in precising the understanding of both dynamics and chemistry in the deep atmopshere of Venus. This work has been funded by the CNES space agency.

  9. Parametric analyses of vapor-anode, multitube AMTEC cells for Pluto/Express mission

    NASA Astrophysics Data System (ADS)

    El-Genk, Mohamed S.; Tournier, Jean-Michel

    1998-01-01

    A detailed AMTEC Performance and Evaluation Analysis Model (APEAM) was used to evaluate the effects of various design changes on the performance of next-generation, Pluto/Express multitube cells. These changes were: using a CREARE condenser; changing the number of BASE tubes and the electrode length; using other electrode materials; using molybdenum (Mo) as the structural material on the hot side of the cell; and using reflective rhodium coatings in the low vapor pressure cavity of the cell. The present analyses utilized a PX-5A type cell, with a Mo circumferential radiation shield, and 7 BASE tubes with 29 mm-long electrodes. Analyses performed for an output load voltage of 3.5 V per cell showed that: (a) A stainless steel (SS) cell with improved electrodes (50% lower contact resistance than TiN, and an increased exchange current, B=200 A.K1/2/Pa.m2) could deliver 7.1 We with an efficiency of 19.5% (b) When Mo was substituted for the SS on the hot side of this cell, the electrical power output increased to 8.8 We and the cell efficiency increased to 20.2% (c) Using rhodium coatings in the Mo/SS cell increased the electrical power output to 9.7 We, and the peak efficiency by 2.3 points, to 22.5%.

  10. Episodic plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Turcotte, Donald

    1992-01-01

    Studies of impact craters on Venus from the Magellan images have placed important constraints on surface volcanism. Some 840 impact craters have been identified with diameters ranging from 2 to 280 km. Correlations of this impact flux with craters on the Moon, Earth, and Mars indicate a mean surface age of 0.5 +/- 0.3 Ga. Another important observation is that 52 percent of the craters are slightly fractured and only 4.5 percent are embayed by lava flows. These observations led researchers to hypothesize that a pervasive resurfacing event occurred about 500 m.y. ago and that relatively little surface volcanism has occurred since. Other researchers have pointed out that a global resurfacing event that ceased about 500 MYBP is consistent with the results given by a recent study. These authors carried out a series of numerical calculations of mantle convection in Venus yielding thermal evolution results. Their model considered crustal recycling and gave rapid planetary cooling. They, in fact, suggested that prior to 500 MYBP plate tectonics was active in Venus and since 500 MYBP the lithosphere has stabilized and only hot-spot volcanism has reached the surface. We propose an alternative hypothesis for the inferred cessation of surface volcanism on Venus. We hypothesize that plate tectonics on Venus is episodic. Periods of rapid plate tectonics result in high rates of subduction that cool the interior resulting in more sluggish mantle convection.

  11. Wave granulation in the Venus' atmosphere

    NASA Astrophysics Data System (ADS)

    Kochemasov, G.

    2007-08-01

    In unique venusian planetary system the solid body rotates very slowly and the detached massive atmosphere very rapidly. However both together orbit Sun and their characteristic orbital frequency -1/ 0.62 year - places them in the regular row of planets assigning them characteristic only for Venus wave produced granulation with a granule size ?R/6 [1& others]. Remind other bodies in the row with their granule sizes inversely proportional to their orbital frequencies: solar photosphere ?R/60, Mercury ?R/16, Venus ?R/6, Earth ?R/4, Mars ?R/2, asteroids ?R/1 (R-a body radius). Three planets have atmospheres with wave granulations having sizes equal to their lithospheric granules. But Venus, unlike Earth and Mars, has the detached atmosphere that can be considered as a separate body with its own orbital frequency around the center of the Venus' system. According to the correlation between an orbital frequency and a wave granule size the venusian wave granule will be ?R/338 (a scale can be Earth: orbital frequency 1/ 1year, granule size ?R/4 or Sun: frequency 1/1month, granule size ?R/60). So, ?R/338 = 57 km. This theoretical size is rather close to that observed by Galileo SC through a violet filter "the filamentary dark features. . . are here revealed to be composed of several dark nodules, like beads on a string, each about 60 miles across" (PIA00072). Actually all Venus' disc seen from a distance ~1.7mln.miles is peppered with these fine features seen on a limit of resolution. So, the Venus' atmosphere has two main frequencies in the solar system with corresponding wave granulations: around Sun 1/225 days (granule ?R/6) and around Venus 1/ 4 days (granule ?R/338). As was done for the Moon, Phobos, Titan and other icy satellites of Saturn [2, 3, 4 & others] one can apply the wave modulation technique also for the atmosphere of Venus. The lower frequency modulates the higher one by dividing and multiplying it thus getting two side frequencies and corresponding them wave granule sizes. (1/338 : 1/6)?R = ?R/56.3 = 342 km. (1/338 x 1/6)?R = ?R/2028 = 9.5 km. The larger granules as well arranged network were seen in the near IR Galileo image PIA00073 (several miles below the visible cloud tops). The smaller granules, hopefully, will be detected by the Venus Express cameras. So, the wave planetology applying wave methods to solid planetary bodies and to surrounding them gaseous envelopes shows their structural unity. This understanding may help to analyze and predict very complex behavior of atmospheric sells at Earth (anticyclones up to 5000 km across or ?R/4), other planets and Titan. Long time ago known the solar supergranules about 30000 km across were never fully understood. The comparative wave planetology placing them together with wave features of planets and satellites throws light on their origin and behavior and thus expands into an area of the solar physics. In this respect it is interesting to note that rather typical for Sun radio emission in 1 meter diapason also was never properly explained. But applying modulation of the solar photosphere frequency 1/ 1month by the Galaxy frequency 1/ 200 000 000 y. one can obtain such short waves [5]. Radio emissions of planets of the solar system also can be related to this modulation by Galaxy rotation [5]. References: [1] Kochemasov G.G. (1992) Comparison of blob tectonics (Venus) and pair tectonics (Earth) // LPS XXIII, Houston, LPI, pt. 2, 703-704; [2] Kochemasov G.G. (2000) Orbiting frequency modulation in Solar system and its imprint in shapes and structures of celestial bodies // Vernadsky-Brown microsymposium 32 on Comparative planetology, Oct. 9-11, 2000, Moscow, Russia, Abstracs, 88-89; [3] Kochemasov G.G. (2000) Titan: frequency modulation of warping waves // Geophys. Res. Abstr., v. 2, (CD-ROM); [4] Kochemasov G.G. (2005) Cassini' lessons: square craters, shoulderto- shoulder even-size aligned and in grids craters having wave interference nature must be taken out of an impact craters statistics to make it real // Vernadsky-Brown

  12. Wave granulation in the Venus' atmosphere

    NASA Astrophysics Data System (ADS)

    Kochemasov, G.

    2007-08-01

    In unique venusian planetary system the solid body rotates very slowly and the detached massive atmosphere very rapidly. However both together orbit Sun and their characteristic orbital frequency -1/ 0.62 year - places them in the regular row of planets assigning them characteristic only for Venus wave produced granulation with a granule size ?R/6 [1& others]. Remind other bodies in the row with their granule sizes inversely proportional to their orbital frequencies: solar photosphere ?R/60, Mercury ?R/16, Venus ?R/6, Earth ?R/4, Mars ?R/2, asteroids ?R/1 (R-a body radius). Three planets have atmospheres with wave granulations having sizes equal to their lithospheric granules. But Venus, unlike Earth and Mars, has the detached atmosphere that can be considered as a separate body with its own orbital frequency around the center of the Venus' system. According to the correlation between an orbital frequency and a wave granule size the venusian wave granule will be ?R/338 (a scale can be Earth: orbital frequency 1/ 1year, granule size ?R/4 or Sun: frequency 1/1month, granule size ?R/60). So, ?R/338 = 57 km. This theoretical size is rather close to that observed by Galileo SC through a violet filter "the filamentary dark features. . . are here revealed to be composed of several dark nodules, like beads on a string, each about 60 miles across" (PIA00072). Actually all Venus' disc seen from a distance ?1.7mln.miles is peppered with these fine features seen on a limit of resolution. So, the Venus' atmosphere has two main frequencies in the solar system with corresponding wave granulations: around Sun 1/225 days (granule ?R/6) and around Venus 1/ 4 days (granule ?R/338). As was done for the Moon, Phobos, Titan and other icy satellites of Saturn [2, 3, 4 & others] one can apply the wave modulation technique also for the atmosphere of Venus. The lower frequency modulates the higher one by dividing and multiplying it thus getting two side frequencies and corresponding them wave granule sizes. (1/338 : 1/6)?R = ?R/56.3 = 342 km. (1/338 x 1/6)?R = ?R/2028 = 9.5 km. The larger granules as well arranged network were seen in the near IR Galileo image PIA00073 (several miles below the visible cloud tops). The smaller granules, hopefully, will be detected by the Venus Express cameras. So, the wave planetology applying wave methods to solid planetary bodies and to surrounding them gaseous envelopes shows their structural unity. This understanding may help to analyze and predict very complex behavior of atmospheric sells at Earth (anticyclones up to 5000 km across or ?R/4), other planets and Titan. Long time ago known the solar supergranules about 30000 km across were never fully understood. The comparative wave planetology placing them together with wave features of planets and satellites throws light on their origin and behavior and thus expands into an area of the solar physics. In this respect it is interesting to note that rather typical for Sun radio emission in 1 meter diapason also was never properly explained. But applying modulation of the solar photosphere frequency 1/ 1month by the Galaxy frequency 1/ 200 000 000 y. one can obtain such short waves [5]. Radio emissions of planets of the solar system also can be related to this modulation by Galaxy rotation [5]. References: [1] Kochemasov G.G. (1992) Comparison of blob tectonics (Venus) and pair tectonics (Earth) // LPS XXIII, Houston, LPI, pt. 2, 703-704; [2] Kochemasov G.G. (2000) Orbiting frequency modulation in Solar system and its imprint in shapes and structures of celestial bodies // Vernadsky-Brown microsymposium 32 on Comparative planetology, Oct. 9-11, 2000, Moscow, Russia, Abstracs, 88-89; [3] Kochemasov G.G. (2000) Titan: frequency modulation of warping waves // Geophys. Res. Abstr., v. 2, (CD-ROM); [4] Kochemasov G.G. (2005) Cassini' lessons: square craters, shoulderto- shoulder even-size aligned and in grids craters having wave interference nature must be taken out of an impact craters statistics to make it real // Vernadsky-Brown

  13. Geologic map of the Carson Quadrangle (V-43), Venus

    USGS Publications Warehouse

    Bender, Kelly C.; Senske, David A.; Greeley, Ronald

    2000-01-01

    The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the venusian atmosphere on October 12, 1994. Magellan had the objectives of (1) improving knowledge of the geologic processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving knowledge of the geophysics of Venus by analysis of venusian gravity. The Magellan spacecraft carried a 12.6-cm radar system to map the surface of Venus. The transmitter and receiver systems were used to collect three datasets: synthetic aperture radar (SAR) images of the surface, passive microwave thermal emission observations, and measurements of the backscattered power at small angles of incidence, which were processed to yield altimetric data. Radar imaging and altimetric and radiometric mapping of the venusian surface were done in mission cycles 1, 2, and 3, from September 1990 until September 1992. Ninety-eight percent of the surface was mapped with radar resolution of approximately 120 meters. The SAR observations were projected to a 75-m nominal horizontal resolution; these full-resolution data compose the image base used in geologic mapping. The primary polarization mode was horizontal-transmit, horizontal-receive (HH), but additional data for selected areas were collected for the vertical polarization sense. Incidence angles varied from about 20° to 45°. High-resolution Doppler tracking of the spacecraft was done from September 1992 through October 1994 (mission cycles 4, 5, 6). High-resolution gravity observations from about 950 orbits were obtained between September 1992 and May 1993, while Magellan was in an elliptical orbit with a periapsis near 175 kilometers and an apoapsis near 8,000 kilometers. Observations from an additional 1,500 orbits were obtained following orbitcircularization in mid-1993. These data exist as a 75° by 75° harmonic field.

  14. Geologic map of the Pandrosos Dorsa Quadrangle (V-5), Venus

    USGS Publications Warehouse

    Rosenberg, Elizabeth; McGill, George E.

    2001-01-01

    Introduction The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphere on October 12, 1994. Magellan had the objectives of (1) improving knowledge of the geologic processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving knowledge of the geophysics of Venus by analysis of Venusian gravity. The Magellan spacecraft carried a 12.6-cm radar system to map the surface of Venus. The transmitter and receiver systems were used to collect three datasets: synthetic aperture radar (SAR) images of the surface, passive microwave thermal emission observations, and measurements of the backscattered power at small angles of incidence, which were processed to yield altimetric data. Radar imaging and altimetric and radiometric mapping of the Venusian surface were done in mission cycles 1, 2, and 3, from September 1990 until September 1992. Ninety-eight percent of the surface was mapped with radar resolution of approximately 120 meters. The SAR observations were projected to a 75-m nominal horizontal resolution; these full-resolution data compose the image base used in geologic mapping. The primary polarization mode was horizontal-transmit, horizontal-receive (HH), but additional data for selected areas were collected for the vertical polarization sense. Incidence angles varied from about 20? to 45?. High-resolution Doppler tracking of the spacecraft was done from September 1992 through October 1994 (mission cycles 4, 5, 6). High-resolution gravity observations from about 950 orbits were obtained between September 1992 and May 1993, while Magellan was in an elliptical orbit with a periapsis near 175 kilometers and an apoapsis near 8,000 kilometers. Observations from an additional 1,500 orbits were obtained following orbitcircularization in mid-1993. These data exist as a 75? by 75? harmonic field.

  15. Geological map of the Kaiwan Fluctus Quadrangle (V-44), Venus

    USGS Publications Warehouse

    Bridges, Nathan T.; McGill, George E.

    2002-01-01

    Introduction The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the Venusian atmosphereon October 12, 1994. Magellan had the objectives of: (1) improving knowledge of the geologic processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving knowledge of the geophysics of Venus by analysis of Venusian gravity. The Magellan spacecraft carried a 12.6-cm radar system to map the surface of Venus. The transmitter and receiver systems were used to collect three datasets: synthetic aperture radar (SAR) images of the surface, passive microwave thermal emission observations, and measurements of the backscattered power at small angles of incidence, which were processed to yield altimetric data. Radar imaging and altimetric and radiometric mapping of the Venusian surface were done in mission cycles 1, 2, and 3, from September 1990 until September of 1992. Ninety-eight percent of the surface was mapped with radar resolution of approximately 120 meters. The SAR observations were projected to a 75-m nominal horizontal resolution; these full-resolution data compose the image base used in geologic mapping. The primary polarization mode was horizontal-transmit, horizontal receive (HH), but additional data for selected areas were collected for the vertical polarization sense. Incidence angles varied from about 20? to 45?. High-resolution Doppler tracking of the spacecraft was done from September 1992 through October 1994 (mission cycles 4, 5, 6). High-resolution gravity observations from about 950 orbits were obtained between September 1992 and May 1993, while Magellan was in an elliptical orbit with a periapsis near 175 kilometers and an apoapsis near 8,000 kilometers. Observations from an additional 1,500 orbits were obtained following orbit-circularization in mid-1993. These data exist as a 75? by 75? harmonic field.

  16. Geologic map of the Bell Regio Quadrangle (V-9), Venus

    USGS Publications Warehouse

    Campbell, Bruce A.; Campbell, Patricia G.

    2002-01-01

    The Magellan spacecraft orbited Venus from August 10, 1990, until it plunged into the venusian atmosphere on October 12, 1994. Magellan had the objectives of (1) improving knowledge of the geologic processes, surface properties, and geologic history of Venus by analysis of surface radar characteristics, topography, and morphology and (2) improving knowledge of the geophysics of Venus by analysis of venusian gravity. The Magellan spacecraft carried a 12.6-cm radar system to map the surface of Venus. The transmitter and receiver systems were used to collect three datasets: synthetic aperture radar (SAR) images of the surface, passive microwave thermal emission observations, and measurements of the backscattered power at small angles of incidence, which were processed to yield altimetric data. Radar imaging and altimetric and radiometric mapping of the venusian surface were done in mission cycles 1, 2, and 3, from September 1990 until September 1992. Ninety-eight percent of the surface was mapped with radar resolution of approximately 120 meters. The SAR observations were projected to a 75-m nominal horizontal resolution; these full-resolution data compose the image base used in geologic mapping. The primary polarization mode was horizontal-transmit, horizontal-receive (HH), but additional data for selected areas were collected for the vertical polarization sense. Incidence angles varied from about 20° to 45°. High-resolution Doppler tracking of the spacecraft was done from September 1992 through October 1994 (mission cycles 4, 5, 6). High-resolution gravity observations from about 950 orbits were obtained between September 1992 and May 1993, while Magellan was in an elliptical orbit with a periapsis near 175 kilometers and an apoapsis near 8,000 kilometers. Observations from an additional 1,500 orbits were obtained following orbitcircularization in mid-1993. These data exist as a 75° by 75° harmonic field.

  17. Gravity waves in the upper atmosphere of Venus revealed by CO2 nonlocal thermodynamic equilibrium emissions

    E-print Network

    Occhipinti, Giovanni "Ninto"

    mission are used to analyze perturbations of CO2 nonlocal thermodynamic equilibrium emissionsGravity waves in the upper atmosphere of Venus revealed by CO2 nonlocal thermodynamic equilibrium revealed by CO2 nonlocal thermodynamic equilibrium emissions, J. Geophys. Res., 114, E00B32, doi:10

  18. Dual Balloon Concept for Lifting Payloads from the Surface of Venus

    NASA Technical Reports Server (NTRS)

    Kerzhanovich, Viktor V.; Yavrouian, A. H.; Hall, J. L.; Cutts, J. A.

    2005-01-01

    Introduction: Two high-rated Venus mission concepts proposed in the National Science Foundation Decadal Survey require a balloon to lift payloads from Venusian surface to high altitudes: Venus Surface Sample Return (VESSR) and Venus In-Situ Explorer (VISE). In case of VESSR the payload is a canister with the surface sample plus a Venus ascent vehicle (VAV), which is a rocket that takes the sample into orbit for rendezvous with an Earth return vehicle. VISE is envisioned as a more limited precursor mission where the surface sample is only taken to high altitudes so that non time-critical analyses can be performed. From the balloon point of view, the only difference between these two missions is that the VESSR payload to be lifted is very much larger than VISE because of the inclusion of the VAV. A key problem is that at the time the decadal survey was published, no high temperature balloon technology existed to implement either mission. Prior technology development efforts had concentrated on a single balloon that could operate across the entire 0-60 km altitude range, tolerating both the sulfuric acid aerosols and the extreme temperatures of -10 to +460 C. However, this problem was unsolved because no combination of sufficiently lightweight balloon material and manufacturing (seaming) technology was ever found to tolerate the high temperatures at the surface.

  19. Hotspots on Venus: Possible recent activity at Themis Regio

    NASA Astrophysics Data System (ADS)

    Stofan, E. R.; Smrekar, S. E.; Helbert, J.; Mueller, N. T.

    2012-12-01

    Themis Regio, Venus is a 2300 x 1700 km topographic rise, with an average height of about 0.5 km. It is one of the ~10 hotspots on Venus, thought to be underlain by a mantle plume (e.g., Stofan and Smrekar, 2005). Thirteen coronae are located on the rise, with an additional six in the surrounding region (Stofan and Brian, 2012). In addition, six volcanoes with diameters > 100 km are found on and near the rise, along with numerous intermediate and smaller volcanoes. The Themis rise lies at the western end of the Parga Chasma rift system. Flows associated with Themis coronae, volcanoes and plains both superpose and are cut by Parga fractures and graben. Recent mapping of Themis Regio reveals a complex history of corona, volcano and rift formation that has overlapped in time and space (Stofan and Brian, 2012). Smrekar and Stofan (1999) found that gravity data for Themis was best fit by a bottom-loading model with an elastic thickness estimate of 22 km, a crustal thickness of 10 km, and an apparent depth of compensation of 80-110 km. The observed range in morphologies of the Themis coronae indicating a range in stages of evolution, along with the delamination signal seen in the gravity data, and the broad topographic swell indicate that Themis is likely to be underlain by an active plume with ongoing surface deformation due to delamination. In addition, the complex sequence of corona formation observed at Themis suggests that a series of small-scale upwellings over time are responsible for corona formation, rather than nearly simultaneously from the break-up of a single large-scale mantle plume (Stofan and Smrekar, 2005). VIRTIS data from the Venus Express mission has provided evidence that relatively recent volcanic activity may have occurred in the region (Smrekar et al., 2010). Fifteen locations on or near the Themis rise have elevated values of emissivity in the VIRTIS data. We investigate all of these regions, and find them to be correlated with areas of volcanic activity, associated with either coronae or volcanoes. While a few of the high emissivity spots are associated with steep-sided domes, most are associated with flows that are likely to be basaltic in origin. The anomalies occur on both topographically elevated terrain as well as on relatively low-lying plains. Based on their morphology and stratigraphic relations with surrounding units, we interpret all of the features to provide evidence of volcanic activity that likely occurred within the last 250,000 years (e.g., Smrekar et al., 2010). References: Smrekar, S.E. and E.R. Stofan, Icarus 139, 100, 1999; Smrekar, S.E. et al., Science 328, 305, 2010; Stofan, E.R. and A.W. Brian, U.S.G.S. SIM- 3165, 2012; Stofan, E.R. and S.E. Smrekar, GSA Spec. Paper 388, 841, 2005.

  20. Clouds of Venus. Input to VIRA.

    NASA Astrophysics Data System (ADS)

    Ignatiev, Nikolay; Zasova, Ludmila

    2012-07-01

    Venus is completely covered by a thick clod deck. Its' total optical depth in the visible is equal to 30+/-10. Original VIRA model based on the measurements from Pioneer Venus descent probes and orbiter described mainly cloud particle sizes, properties and their vertical distribution. Later measurements from Venera-15 and Venus Express permitted more detailed studies of horizontal and vertical variations. Imaging of Venus in the UV range shows variety of cloud features that include mottled and streaky clouds in the low latitudes, bright mid-latitude belt and ``polar cap'' with imbedded oval polar dipole. Despite this non-uniform picture the location of the upper boundary of the clouds, derived from the observation of the absorption bands in the reflected IR spectrum, demonstrates a smooth systematic behavior with the latitudinal trends symmetric with respect to equator. In low and middle latitudes the cloud top is located at 72+/-1 km. It decreases poleward of +/-50 degrees and reaches 63--69 km in polar regions. This depression coincides with the eye of the planetary vortex. The effective average particle size radius is equal to (1.3+/-0.5) micron at latitudes of 0--70, with a peak value some 50% larger in the polar regions. Cloud top can experience fast variations of about metricconverterProductID1 km1 km in tens of hours, while larger long-term variations of several kilometers have been observed only at high latitudes. UV markings correlate with the cloud altimetry, however the difference between adjacent UV dark and bright regions never exceeds few hundred meters. Ultraviolet dark spiral arms, which are often seen at about --70 degress, correspond to higher altitudes or to the regions with strong latitudinal gradient of the cloud top altitude. In contrast to the relatively uniform upper cloud boundary, strong variations of the brightness temperature at specific near infrared wavelengths, especially in low latitudes, are related to variations of the cloud thickness in the middle and low cloud decks consistent with significant convective activity at these levels. The morphology of the holes tends from highly variable orientations of features with aspect ratios of nearly one at low latitudes, to very large aspect ratios and zonally oriented features at higher latitudes.

  1. Venus - Barton Crater

    NASA Technical Reports Server (NTRS)

    1991-01-01

    During orbits 404 through 414 on 19-20 September 1990, Magellan imaged a peak-ring crater that is 50 kilometers in diameter located at latitude 27.4 degrees north and longitude 337.5 degrees east. The name Barton has been proposed by the Magellan Science Team for this crater, after Clara Barton, founder of the Red Cross; however, the name is tentative pending approval by the International Astronomical Union.

    Barton is just at the diameter size that Venus craters appear to begin to possess peak-rings instead of a single central peak or central peak complex like does 75 percent of the craters with diameters between 50 and about 15 kilometers. The floor of the crater is flat and radar-dark, indicating possible infilling by volcanic deposits sometime following the impact event. Barton's central peak ring is discontinuous and appears to have been disrupted or separated during or following the cratering process. The extremely blocky crater deposits (ejecta) surrounding Barton appear to be most extensive on the southwest to southeast (lower left to right) side of the crater.

  2. Response of Venus exospheric temperature measured by neutral mass spectrometer to solar EUV flux measured by Langmuir probe on the Pioneer Venus orbiter

    SciTech Connect

    Mahajan, K.K.; Kasprzak, W.T.; Brace, L.H.; Niemann, H.B.; Hoegy, W.R. )

    1990-02-01

    The photoelectron current from the Pioneer Venus Langmuir probe has provided measurements of the total flux of solar EUV photons at Venus since 1979. The neutral oxygen scale height measured by the orbiter neutral mass spectrometer has permitted the exospheric temperature to be derived furing the same mission. In this paper the EUV observations are used to examine the response of exospheric temperature to changes in solar activity, primarily those related to solar rotation. It is found that the dayside exospheric temperature quite faithfully tracks variations in the EUV flux. Comparison is also made with the Earth-based solar activity index F{sub 10.7} adjusted to the position of Venus. This index varied from 142 to 249 flux units (10{sup {minus}22} W m{sup {minus}2} Hz{sup {minus}1}) during the period of measurements. The exospheric temperature is better correlated with EUV flux than with the 10.7-cm solar radio flux.

  3. Response of Venus exospheric temperature measured by neutral mass spectrometer to solar EUV flux measured by Langmuir probe on the Pioneer Venus orbiter

    NASA Technical Reports Server (NTRS)

    Mahajan, K. K.; Kasprzak, W. T.; Brace, L. H.; Niemann, H. B.; Hoegy, W. R.

    1990-01-01

    The photoelectron current from the Pioneer Venus Langmuir probe has provided measurements of the total flux of solar EUV photons at Venus since 1979. The neutral oxygen scale height measured by the orbiter neutral mass spectrometer has permitted the exospheric temperature to be derived during the same mission. In this paper, the EUV observations are used to examine the response of exospheric temperature to changes in solar activity, primarily those related to solar rotation. It is found that the dayside exospheric temperature quite faithfully tracks variations in the EUV flux. Comparison is also made with the earth-based solar activity index F10.7 adjusted to the position of Venus. This index varied from 142 to 249 flux units during the period of measurements. The exospheric temperature is better correlated with EUV flux than with the 10.7-cm solar radio flux.

  4. A comparison of induced magnetotails of planetary bodies: Venus, Mars, and Titan

    SciTech Connect

    Luhmann, J.G.; Russell, C.T. ); Schwingenschuh, K. ); Yeroshenko, Ye. )

    1991-07-01

    The Pioneer Venus orbiter (PVO), PHOBOS 2, and Voyager 1 spacecraft have together provided observations of three planetary bodies with induced magnetotails: Venus, Mars, and Titan. During the extended mission of PVO, the tail of Venus was probed at an altitude of {approximately} 1.3 planetary radii, which provided a more appropriate basis for comparison with the Mars data (at {approximately} 2.7 planetary radii), and Titan data ({approximately} 2.5 planetary radii downstream), then the previously analyzed Venus tail data obtained near PVO apoapsis ({approximately} 12 planetary radii). A parallel examination of the magnetic properties of these tails at downstream distances within 3 planetary radii reveals the following similarities and differences. In the cases of Venus and Mars, which are always embedded in the supermagnetosonic solar wind flow, the tail lobe fields are smoothly joined to the draped magnetosheath fields at their outer boundaries, but separated in the center by a distinct, and sometimes narrow, current sheet. The tail of Mars has a cross section that is wider, when scaled by the planet radius, than that at Venus (as found by earlier MARS spacecraft experiments), a lobe field strength that is about the same as that at Venus by {approximately}1.5 times. The tail of Titan appears similar to the others except that there is no bow shock and little or no draped magnetosheath field signature since the surrounding magnetospheric plasma flow is submagnetosonic (although super-Alfvenic). The lobe field strengths are about half those at Venus and Mars, while the cross-tail field is almost negligible. The near-Titan tail diameter is close to the body diameter.

  5. WEGENER: Solid Body Dynamics Investigation of Venus. Results from Summer School Alpbach 2014.

    NASA Astrophysics Data System (ADS)

    Bialek, A.; Coyle, S.; Czeluschke, A.; Donaldson Hanna, K.; Donohoe, A.; Hu, H.; Koopmans, R.-J.; Lucchetti, A.; Mannel, T.; Nachon, M.; Nilsson, D.; Shelakhaev, N.; Suer, A.; Timoney, R.

    2015-10-01

    The work presented in this paper was performed by the Orange Team during Summer School Alpbach 2014, which mainly concerns about geophysics of terrestrial planets. A mission is designed to investigate the past and current tectonic and volcanic activity on Venus. During the mission, a simultaneous observations from topographic, magnetic and gravitational measurements will be performed and the combination of the information has the potential to provide an improved understanding of the formation and evolution of the planet.

  6. A survey of hot flow anomalies at Venus

    NASA Astrophysics Data System (ADS)

    Collinson, G. A.; Sibeck, D. G.; Masters, A.; Shane, N.; Zhang, T. L.; Fedorov, A.; Barabash, S.; Coates, A. J.; Moore, T. E.; Slavin, J. A.; Uritsky, V. M.; Boardsen, S.; Sarantos, M.

    2014-02-01

    We present the first survey of hot flow anomalies (HFAs) at the bow shock of Venus, expanding on our recent initial case study. A 3.06 sol (774 Earth day) survey of Venus Express magnetometer, ion spectrometer, and electron spectrometer data was undertaken in order to identify Cytherian HFAs. Seven events were discovered, corresponding to a statistical frequency ?1.2±0.8 per day, approximately the same rate as at the Earth. All seven HFAs were centered on a discontinuity in the solar wind, with inward pointing motional electric fields on at least one side, and exhibited electron and ion perturbations consistent with heating. For one event the calculation of continuous electron moments is possible, revealing that electron temperature increased from ?2×105 K to 8×105 K in the HFA core (comparable to terrestrial and Kronian HFA observations), and density increased from ?1 cm-3 to ~2?2.5 cm-3 in the bounding compression regions. Cytherian HFAs were found to be physically smaller (0.4?1.7 Venus radii (RV)) than their terrestrial or Kronian counterparts, although are much larger when compared to the overall size of the system (?130% of the subsolar bow shock distance), and occur very close (1.5?3.0RV) to the planet. Thus, we hypothesize that HFAs have a much more dominant role in the dynamics of the induced magnetosphere of Venus relative to the magnetospheres of magnetized planets.

  7. A mantle plume model for the Equatorial Highlands of Venus

    NASA Technical Reports Server (NTRS)

    Kiefer, Walter S.; Hager, Bradford H.

    1991-01-01

    The possibility that the Equatorial Highlands are the surface expressions of hot upwelling mantle plumes is considered via a series of mantle plume models developed using a cylindrical axisymmetric finite element code and depth-dependent Newtonian rheology. The results are scaled by assuming whole mantle convection and that Venus and the earth have similar mantle heat flows. The best model fits are for Beta and Atla. The common feature of the allowed viscosity models is that they lack a pronounced low-viscosity zone in the upper mantle. The shape of Venus's long-wavelength admittance spectrum and the slope of its geoid spectrum are also consistent with the lack of a low-viscosity zone. It is argued that the lack of an asthenosphere on Venus is due to the mantle of Venus being drier than the earth's mantle. Mantle plumes may also have contributed to the formation of some smaller highland swells, such as the Bell and Eistla regions and the Hathor/Innini/Ushas region.

  8. Rate of volcanism on Venus

    SciTech Connect

    Fegley, B. Jr.; Prinn, R.G.

    1988-07-01

    The maintenance of the global H/sub 2/SO/sub 4/ clouds on Venus requires volcanism to replenish the atmospheric SO/sub 2/ which is continually being removed from the atmosphere by reaction with calcium minerals on the surface of Venus. The first laboratory measurements of the rate of one such reaction, between SO/sub 2/ and calcite (CaCO/sub 3/) to form anhydrite (CaSO/sub 4/), are reported. If the rate of this reaction is representative of the SO/sub 2/ reaction rate at the Venus surface, then we estimate that all SO/sub 2/ in the Venus atmosphere (and thus the H/sub 2/SO/sub 4/ clouds) will be removed in 1.9 million years unless the lost SO/sub 2/ is replenished by volcanism. The required rate of volcanism ranges from about 0.4 to about 11 cu km of magma erupted per year, depending on the assumed sulfur content of the erupted material. If this material has the same composition as the Venus surface at the Venera 13, 14 and Vega 2 landing sites, then the required rate of volcanism is about 1 cu km per year. This independent geochemically estimated rate can be used to determine if either (or neither) of the two discordant (2 cu km/year vs. 200 to 300 cu km/year) geophysically estimated rates is correct. The geochemically estimated rate also suggests that Venus is less volcanically active than the Earth.

  9. Special issue editorial - Plasma interactions with Solar System Objects: Anticipating Rosetta, Maven and Mars Orbiter Mission

    NASA Astrophysics Data System (ADS)

    Coates, A. J.; Wellbrock, A.; Yamauchi, M.

    2015-12-01

    Within our solar system, the planets, moons, comets and asteroids all have plasma interactions. The interaction depends on the nature of the object, particularly the presence of an atmosphere and a magnetic field. Even the size of the object matters through the finite gyroradius effect and the scale height of cold ions of exospheric origin. It also depends on the upstream conditions, including position within the solar wind or the presence within a planetary magnetosphere. Soon after ESA's Rosetta reached comet Churyumov-Gerasimenko, NASA's Maven and ISRO's Mars Orbiter Mission (MOM) reached Mars, and ESA's Venus Express mission was completed, this issue explores our understanding of plasma interactions with comets, Mars, Venus, and moons in the solar system. We explore the processes which characterise the interactions, such as ion pickup and field draping, and their effects such as plasma escape. Papers are based on data from current and recent space missions, modelling and theory, as we explore our local part of the 'plasma universe'.

  10. Venus - Global surface radio emissivity

    NASA Technical Reports Server (NTRS)

    Ford, P. G.; Pettengill, G. H.

    1983-01-01

    Observations of thermal radio emission from the surface of Venus, made by the Pioneer Venus radar mapper at a wavelength of 17 cm, show variations that are dominated by changes in surface emissivity. The regions of lowest emissivity (0.54 + or - 0.05 for the highland areas of Aphrodite Terra and Theia Mons) correspond closely to regions of high radar reflectivity reported earlier. These results support the inference of inclusions of material with high electrical conductivity in the surface rock of these areas.

  11. A Summary of the Rendezvous, Proximity Operations, Docking, and Undocking (RPODU) Lessons Learned from the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) Demonstration System Mission

    NASA Technical Reports Server (NTRS)

    Dennehy, Cornelius J.; Carpenter, James R.

    2011-01-01

    The Guidance, Navigation, and Control (GN&C) Technical Discipline Team (TDT) sponsored Dr. J. Russell Carpenter, a Navigation and Rendezvous Subject Matter Expert (SME) from NASA's Goddard Space Flight Center (GSFC), to provide support to the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) rendezvous and docking flight test that was conducted in 2007. When that DARPA OE mission was completed, Mr. Neil Dennehy, NASA Technical Fellow for GN&C, requested Dr. Carpenter document his findings (lessons learned) and recommendations for future rendezvous missions resulting from his OE support experience. This report captures lessons specifically from anomalies that occurred during one of OE's unmated operations.

  12. Venus Atmospheric Exploration by Solar Aircraft

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; LaMarre, C.; Colozza, A.

    2002-01-01

    The Venus atmosphere is a favorable environment for flying powered aircraft. The atmospheric pressure makes flight much easier than on planets such as Mars. Above the clouds, solar energy is available in abundance on Venus, and the slow rotation of Venus allows a solar airplane to be designed for flight within continuous sunlight. The atmosphere between 50 km and 75 km on Venus is one of the most dynamic and interesting regions of the planet. The challenge for a Venus aircraft will be the fierce winds and caustic atmosphere. In order to remain on the sunlit side of Venus, an exploration aircraft will have to be capable of sustained flight at or above the wind speed. An aircraft would be a powerful tool for exploration. By learning how Venus can be so similar to Earth, and yet so different, we will learn to better understand the climate and geological history of the Earth.

  13. Venus: Craters, Coronae, and Chasmata Donna M. Jurdy

    E-print Network

    Jurdy, Donna M.

    Venus: Craters, Coronae, and Chasmata Donna M. Jurdy Northwestern University #12;Early View of Venus #12;#12;Venus, as seen by Veneras 9 and 10 #12;Venus as seen by Venera 13 (1-Mar-1982) #12;Pioneer Venus Topography #12;Inner Solar System Hypsographic Comparisons #12;Magellan Deployment #12;Magellan

  14. Roadmap for Venus Exploration (Version 4, 1/29/14)

    E-print Network

    Rathbun, Julie A.

    1 Roadmap for Venus Exploration (Version 4, 1/29/14) Introduction Venus is so similar". Despite these similarities, however, Venus has gone down a very different evolutionary path. Venus today the study of Venus provides unique and important opportunities to understand not only the general processes

  15. Power System for Venus Surface Exploration

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Mellott, Kenneth

    2002-01-01

    A radioisotope power and cooling system is designed to provide electrical power for a probe operating on the surface of Venus. Most foreseeable electronics devices and sensors cannot operate at the 450 C ambient surface temperature of Venus. Because the mission duration is substantially long and the use of thermal mass to maintain an operable temperature range is likely impractical, some type of active refrigeration may be required to keep electronic components at a temperature below ambient. The fundamental cooling parameters are the cold sink temperature, the hot sink temperature, and the amount of heat to be removed. In this instance, it is anticipated that electronics would have a nominal operating temperature of 300 C. Due to the highly thermal convective nature of the high-density (90 bar CO2) atmosphere, the hot sink temperature was assumed to be 50 C, which provided a 500 C temperature of the cooler's heat rejecter to the ambient atmosphere. The majority of the heat load on the cooler is from the high temperature ambient surface environment on Venus, with a small contribution of heat generation from electronics and sensors. Both thermoelectric (RTG) and dynamic power conversion systems were analyzed, based on use of a standard isotope (General-purpose heat source, or GPHS) brick. For the radioisotope Stirling power converter configuration designed, the Sage model predicts a thermodynamic power output capacity of 478.1 watts, which slightly exceeds the required 469.1 watts. The hot sink temperature is 1200 C, and the cold sink temperature is 500 C. The required heat input is 1740 watts. This gives a thermodynamic efficiency of 27.48 %. It is estimated that the mechanical efficiency of the power converter design is on the order of 85 %, based on experimental measurements taken from 500-watt power class, laboratory-tested Stirling engines. The overall efficiency is calculated to be 23.36 %. The mass of the power converter is estimated at approximately 21.6 kg. Additional information is included in the original extended abstract.

  16. Venus Surface Power and Cooling System Design

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Mellott, Kenneth D.

    2004-01-01

    A radioisotope power and cooling system is designed to provide electrical power for the a probe operating on the surface of Venus. Most foreseeable electronics devices and sensors simply cannot operate at the 450 C ambient surface temperature of Venus. Because the mission duration is substantially long and the use of thermal mass to maintain an operable temperature range is likely impractical, some type of active refrigeration may be required to keep certain components at a temperature below ambient. The fundamental cooling requirements are comprised of the cold sink temperature, the hot sink temperature, and the amount of heat to be removed. In this instance, it is anticipated that electronics would have a nominal operating temperature of 300 C. Due to the highly thermal convective nature of the high-density atmosphere, the hot sink temperature was assumed to be 50 C, which provided a 500 C temperature of the cooler's heat rejecter to the ambient atmosphere. The majority of the heat load on the cooler is from the high temperature ambient surface environment on Venus. Assuming 5 cm radial thickness of ceramic blanket insulation, the ambient heat load was estimated at approximately 77 watts. With an estimated quantity of 10 watts of heat generation from electronics and sensors, and to accommodate some level of uncertainty, the total heat load requirement was rounded up to an even 100 watts. For the radioisotope Stirling power converter configuration designed, the Sage model predicts a thermodynamic power output capacity of 478.1 watts, which slightly exceeds the required 469.1 watts. The hot sink temperature is 1200 C, and the cold sink temperature is 500 C. The required heat input is 1740 watts. This gives a thermodynamic efficiency of 27.48 %. The maximum theoretically obtainable efficiency is 47.52 %. It is estimated that the mechanical efficiency of the power converter design is on the order of 85 %, based on experimental measurements taken from 500 watt power class, laboratory-tested Stirling engines at GRC. The overall efficiency is calculated to be 23.36 %. The mass of the power converter is estimated at approximately 21.6 kg.

  17. Extreme Environment Simulation - Current and New Capabilities to Simulate Venus and Other Planetary Bodies

    NASA Technical Reports Server (NTRS)

    Kremic, Tibor; Vento, Dan; Lalli, Nick; Palinski, Timothy

    2014-01-01

    Science, technology, and planetary mission communities have a growing interest in components and systems that are capable of working in extreme (high) temperature and pressure conditions. Terrestrial applications range from scientific research, aerospace, defense, automotive systems, energy storage and power distribution, deep mining and others. As the target environments get increasingly extreme, capabilities to develop and test the sensors and systems designed to operate in such environments will be required. An application of particular importance to the planetary science community is the ability for a robotic lander to survive on the Venus surface where pressures are nearly 100 times that of Earth and temperatures approach 500C. The scientific importance and relevance of Venus missions are stated in the current Planetary Decadal Survey. Further, several missions to Venus were proposed in the most recent Discovery call. Despite this interest, the ability to accurately simulate Venus conditions at a scale that can test and validate instruments and spacecraft systems and accurately simulate the Venus atmosphere has been lacking. This paper discusses and compares the capabilities that are known to exist within and outside the United States to simulate the extreme environmental conditions found in terrestrial or planetary surfaces including the Venus atmosphere and surface. The paper then focuses on discussing the recent additional capability found in the NASA Glenn Extreme Environment Rig (GEER). The GEER, located at the NASA Glenn Research Center in Cleveland, Ohio, is designed to simulate not only the temperature and pressure extremes described, but can also accurately reproduce the atmospheric compositions of bodies in the solar system including those with acidic and hazardous elements. GEER capabilities and characteristics are described along with operational considerations relevant to potential users. The paper presents initial operating results and concludes with a sampling of investigations or tests that have been requested or expected.

  18. Pancakelike domes on Venus

    NASA Technical Reports Server (NTRS)

    Mckenzie, Dan; Ford, Peter G.; Liu, Fang; Pettengill, Gordon H.

    1992-01-01

    The shape of seven large domes on the plains of Venus, with volumes between 100 and 1000 cu km, is compared with that of an axisymmetric gravity current spreading over a rigid horizontal surface. Both the altimetric profiles and the horizontal projection of the line of intersection of domes on the SAR images agree well with the theoretical similarity solution for a newtonian fluid, but not with the shape calculated for a rigid-plastic rheology, nor with that for a static model with a strong skin. As a viscous current spreads, it generates an isotropic strain rate tensor whose magnitude is independent of radius. Such a flow can account for the randomly oriented cracks that are uniformly distributed on the surface of the domes. The stress induced by the flow in the plains material below is obtained, and is probably large enough to produce the short radial cracks in the surface of the plains beyond the domes. The viscosity of the domes can be estimated from their thermal time constants if spreading is possible only when the fluid is hot, and lies between 10(exp 14) and 10(exp 17) Pa s. Laboratory experiments show that such viscosities correspond to temperatures of 610 - 690 C in dry rhyolitic magmas. These temperatures agree with laboratory measurements of the solidus temperature of wet rhyolite. These results show that the development of the domes can be understood using simple fluid dynamical ideas, and that the magmas involved can be produced by wet melting at depths below 10 km, followed by eruption and degassing.

  19. Venus - Ovda Regio

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This image covers much of Ovda Regio, which forms the western part of Aphrodite Terra. It covers an area about 2,250 kilometers (1,386 miles) wide by 1,300 kilometers (800 miles) north to south, and ranges in latitude from 8 degrees north to 12 degrees south and in longitude from 62 degrees east to 90 degrees east. Ovda Regio is a highland region that rises over 4 kilometers (2.5 miles) above the surrounding plain. Magellan images show a complex surface, with several generations of structures. A pervasive fabric of irregular broad domes and ridges and associated curvilinear valleys was flooded by lava, then fractured. The circular feature surrounded by dark lava flows in the western part of the image is a caldera, or large volcanic collapse pit. Late-stage extension created long graben, or fault-bounded valleys, is best seen near the center of the image. The northern boundary of Ovda Regio is a steep, curvilinear mountain belt made up of long, narrow, rounded ridges. These ridges are similar in appearance to folded mountain belts on Earth. Several impact craters, such as the circular features on the western margin of the image, are scattered across the area. The bright area in the southeast part of the image indicates the presence of a radar-reflective mineral such as pyrite. Most of the highland areas on Venus display a similar bright signal. Each pixel of this image covers an area on the surface 675 meters (2,215 feet) across, representing a 9- times reduction in resolution compared to full-scale resolution data.

  20. Neurogenin2-d4Venus and Gadd45g-d4Venus transgenic mice: Visualizing mitotic and migratory behaviors of cells committed to the neuronal lineage in the developing mammalian brain

    PubMed Central

    Kawaue, Takumi; Sagou, Ken; Kiyonari, Hiroshi; Ota, Kumiko; Okamoto, Mayumi; Shinoda, Tomoyasu; Kawaguchi, Ayano; Miyata, Takaki

    2014-01-01

    To achieve highly sensitive and comprehensive assessment of the morphology and dynamics of cells committed to the neuronal lineage in mammalian brain primordia, we generated two transgenic mouse lines expressing a destabilized (d4) Venus controlled by regulatory elements of the Neurogenin2 (Neurog2) or Gadd45g gene. In mid-embryonic neocortical walls, expression of Neurog2-d4Venus mostly overlapped with that of Neurog2 protein, with a slightly (1 h) delayed onset. Although Neurog2-d4Venus and Gadd45g-d4Venus mice exhibited very similar labeling patterns in the ventricular zone (VZ), in Gadd45g-d4Venus mice cells could be visualized in more basal areas containing fully differentiated neurons, where Neurog2-d4Venus fluorescence was absent. Time-lapse monitoring revealed that most d4Venus+ cells in the VZ had processes extending to the apical surface; many of these cells eventually retracted their apical process and migrated basally to the subventricular zone, where neurons, as well as the intermediate neurogenic progenitors that undergo terminal neuron-producing division, could be live-monitored by d4Venus fluorescence. Some d4Venus+ VZ cells instead underwent nuclear migration to the apical surface, where they divided to generate two d4Venus+ daughter cells, suggesting that the symmetric terminal division that gives rise to neuron pairs at the apical surface can be reliably live-monitored. Similar lineage-committed cells were observed in other developing neural regions including retina, spinal cord, and cerebellum, as well as in regions of the peripheral nervous system such as dorsal root ganglia. These mouse lines will be useful for elucidating the cellular and molecular mechanisms underlying development of the mammalian nervous system. PMID:24712911

  1. Venus and Mercury as Planets

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A general evolutionary history of the solar planetary system is given. The previously observed characteristics of Venus and Mercury (i.e. length of day, solar orbit, temperature) are discussed. The role of the Mariner 10 space probe in gathering scientific information on the two planets is briefly described.

  2. Phlogopite Decomposition, Water, and Venus

    NASA Technical Reports Server (NTRS)

    Johnson, N. M.; Fegley, B., Jr.

    2005-01-01

    Venus is a hot and dry planet with a surface temperature of 660 to 740 K and 30 parts per million by volume (ppmv) water vapor in its lower atmosphere. In contrast Earth has an average surface temperature of 288 K and 1-4% water vapor in its troposphere. The hot and dry conditions on Venus led many to speculate that hydrous minerals on the surface of Venus would not be there today even though they might have formed in a potentially wetter past. Thermodynamic calculations predict that many hydrous minerals are unstable under current Venusian conditions. Thermodynamics predicts whether a particular mineral is stable or not, but we need experimental data on the decomposition rate of hydrous minerals to determine if they survive on Venus today. Previously, we determined the decomposition rate of the amphibole tremolite, and found that it could exist for billions of years at current surface conditions. Here, we present our initial results on the decomposition of phlogopite mica, another common hydrous mineral on Earth.

  3. Morphology and dynamics of the Venus upper cloud layer

    NASA Astrophysics Data System (ADS)

    Markiewicz, Wojciech; Titov, Dmitri; Limaye, Sanjay; Moissl, Richard; Ignatiev, Nikolay; Basilevsky, A. T.; Shalygin, E. V.; Kreslavsky, M. A.; Khatuntsev, Igor; Keller, Horst Uwe; Jaumann, Ralf; Thomas, Nicolas; Michalik, Harald

    Venus is completely covered by a thick cloud layer whose upper part is composed of sulfuric acid and some unknown aerosols1. The cloud tops are in fast retrograde rotation (super-rotation), but what is driving this super-rotation is unknown2. Here we report observations of Venus with the Venus Monitoring Camera3 (VMC) on board the Venus Express spacecraft. Taking advantage of the VMC high resolution imaging and the polar orbit we investigate both global and small scale properties of these clouds, their temporal and latitudinal variations, and derive wind velocities. The Southern polar region is highly variable and can change dramatically on time scales as short as one day, perhaps arising from the injection of SO2 into the mesosphere. The convective cells in the vicinity of the sub-solar point are much smaller than previously inferred4,5,6, which we interpret as indicating that they are confined to the upper cloud layer, contrary to previous conclusions7,8, but consistent with more recent study9. (1) Esposito, L.W. et al., in Venus, pp. 484-564, 1983, (2) Limaye, S. S., 2007, J. Geophys. Res., 112, 2007, (3) Markiewicz, W.J. et al., Planet. Space Sci., 55, 1701-1711, 2007, (4) Murray, B.C., et al., Science 183, 1307-1315 (1974), (5) Rossow, W.B. et al., J. Geophys. Res. 85, 8107-8128, 1980, (6) Covey, C.C. and G. Schubert, Nature, 290, 17-20, 1981, (7) Baker II, R.D. and G. Schubert, Nature, 355, 710-712, 1992, (8) Belton, M.J.S. et al., J. Atmos. Sci.. 33, 1394-1417, 1976, (9) Baker, R.D., G. Schubert, and P.W. Jones, J. Geophy. Res., 104, Issue E2, p. 3815-3832, 1999.

  4. Airglow and aurora in the atmospheres of Venus and Mars

    NASA Technical Reports Server (NTRS)

    Fox, J. L.

    1992-01-01

    Measurements and models of the luminosity that originates in the Martian and Venusian atmospheres, including dayglow, nightglow and aurora, are compared. Most of the emission features considered appear in the UV and visible regions of the spectrum and arise from electronic transitions of thermospheric species. Spatially and temporally variable intensities of the oxygen 1304 and 1356 A lines have been observed on the nightside of Venus and have been labeled 'auroral', that is, ascribed to electron precipitation. Only a future aeronomy mission to Mars could unequivocally determine whether such emissions are present on the nightside of Mars.

  5. Abort Options for Potential Mars Missions

    NASA Technical Reports Server (NTRS)

    Tartabini, P. V.; Striepe, S. A.; Powell, R. W.

    1994-01-01

    Mars trajectory design options were examined that would accommodate a premature termination of a nominal manned opposition class mission for opportunities between 2010 and 2025. A successful abort must provide a safe return to Earth in the shortest possible time consistent with mission constraints. In this study, aborts that provided a minimum increase in the initial vehicle mass in low Earth orbit (IMLEO) were identified by locating direct transfer nominal missions and nominal missions including an outbound or inbound Venus swing-by that minimized IMLEO. The ease with which these missions could be aborted while meeting propulsion and time constraints was investigated by examining free return (unpowered) and powered aborts. Further reductions in trip time were made to some aborts by the addition or removal of an inbound Venus swing-by. The results show that, although few free return aborts met the specified constraints, 85% of each nominal mission could be aborted as a powered abort without an increase in propellant. Also, in many cases, the addition or removal of a Venus swing-by increased the number of abort opportunities or decreased the total trip time during an abort.

  6. VENUS: Hypothetical life found at ``a wrong place''

    NASA Astrophysics Data System (ADS)

    Ksanfomality, Leonid

    The position of the hypothetical habitability zone in extrasolar planetary system was considered by many authors. Approximately 1/4 of exoplanets orbit their stars at very low orbits, which leads to high temperatures of their surface (if any), up to 800 K or more. Some of them should have the physical conditions close to those of Venus. Is there any possibility that the life forms can exist at quite different environment than “normal”, Earth-like physical settings? Namely the planet Venus could be the natural laboratory for studies of this type, having the dense, hot (735 K) oxygenless CO2 - atmosphere and high, 9.2 MPa, pressure at the surface. It should be recalled that the only existing data of actual close in TV-observations of Venus’ surface are the results of a series of missions of the Russian VENERA landers which took place the 1970s and 80s, working in the atmosphere and on the surface of Venus. No other results of this kind were obtained since. A re-examination of images of Venusian surface returned from the VENERA landers has been undertaken using a modern processing technique, with a view to detect any possible signs of life under the specific conditions on Venus. This speculative identification rests on two characteristics of these features: (a) their somewhat suggestive morphology and (b) their temporal appearance and behavior (present, than absent on subsequent images of the same area; or changing appearances). The re-exemination has identified previously unreported features that may correspond to hypothetical life forms on Venus’ surface. A new analysis and comparison of the content of the sequence of panoramas of the Venusian surface made in 2013, allowed the author to detect some new interesting objects displayed on the panoramas that hypothetically may be related to fauna and flora of the planet. Some of the objects found were described in a dozen of papers (2012, 2013). There are also found and listed in the report images of objects with special morphology resembling the shape of some terrestrial fauna and flora. References: Ksanfomality L.V. 2013 Doklady Physics. 58 (5), 204 Ksanfomality L.V. 2013 Doklady Physics. 58 (11), 514

  7. Compatibility issues of potential payloads for the USA/9904/B(U)F-85 RTG transportation system (RTGTS) for the ``Pluto Express'' mission

    NASA Astrophysics Data System (ADS)

    Miller, Roger G.; Barklay, Chadwick D.; Howell, Edwin I.; Frazier, Timothy A.

    1997-01-01

    The specific electric power system for the ``Pluto Express'' mission has yet to be specified. However, electric power will be provided by either radioisotopic thermoelectric generators (RTG), radioisotope thermophotovoltaic systems (RTPV), alkali metal thermal to electrical conversion (AMTEC) systems, radioisotope Stirling systems, or a combination of these. The selected radioisotopic power system will also be transported using the USA/9904/B(U)F-85, Radioisotope Thermoelectric Generator (RTG) Transportation System (RTGTS). As a result, all of the potential payloads present uniquely different environmental and physical configuration requirements. This paper presents the major compatibility issues of the potential payloads for the USA/9904/B(U)F-85 RTG Transportation System for the ``Pluto Express'' mission.

  8. Compatibility issues of potential payloads for the USA/9904/B(U)F-85 RTG transportation system (RTGTS) for the 'Pluto Express' mission

    SciTech Connect

    Miller, Roger G.; Barklay, Chadwick D.; Howell, Edwin I.; Frazier, Timothy A.

    1997-01-10

    The specific electric power system for the 'Pluto Express' mission has yet to be specified. However, electric power will be provided by either radioisotopic thermoelectric generators (RTG), radioisotope thermophotovoltaic systems (RTPV), alkali metal thermal to electrical conversion (AMTEC) systems, radioisotope Stirling systems, or a combination of these. The selected radioisotopic power system will also be transported using the USA/9904/B(U)F-85, Radioisotope Thermoelectric Generator (RTG) Transportation System (RTGTS). As a result, all of the potential payloads present uniquely different environmental and physical configuration requirements. This paper presents the major compatibility issues of the potential payloads for the USA/9904/B(U)F-85 RTG Transportation System for the 'Pluto Express' mission.

  9. Venus Express - Status and major results

    NASA Astrophysics Data System (ADS)

    Svedhem, H.; Titov, D.

    2011-10-01

    Studies of the surface in the near infrared have shown several areas of recent geologic activity. These areas correspond well to the suspected 'hot spots' previously identified in the Magellan radar and gravity field maps. Recently the atmospheric density has been probed in situ by reducing the pericentre altitude such that the drag force on the spacecraft has become significant and thus measureable. In this way the altitude range 165-200 km, which is not possible to address with remote measurements, has been characterized. For the first time a new technique has been applied whereby the solar panels are set in an asymmetric position with respect to each other such that a torque is acting on the spacecraft during the atmospheric pass. Since the spacecraft attitude is maintained automatically be the reaction wheels the rotation rate changes of the wheels provide a very sensitive measure of the atmospheric density.

  10. On the origin of Venus' unusual gravity spectrum

    NASA Astrophysics Data System (ADS)

    Rolf, Tobias; Werner, Stephanie; Steinberger, Bernhard

    2015-04-01

    Despite obvious differences in the present state of the terrestrial planets and the Earth's Moon, e.g. in their tectonic mode (plate tectonics, episodic resurfacing, stagnant lid, ...), al these bodies feature a gravity spectrum that is dominated by the spherical harmonic degree 2. The only exception is Venus, which features a degree 3-dominance and a much stronger correlation between geoid and topography at long wavelength than e.g. Earth. Taking this as motivation, we analyze Venus' gravity spectrum in more detail. We use a dynamic model to predict synthetic gravity spectra for a Venus-like planet and compare them to the observed spectrum provided from satellite missions in sufficient detail. It is known that the viscosity structure of a planetary mantle has a strong impact on the spectrum, such that we can in turn use the misfit between observed and predicted spectrum as a constraint for the viscosity profile, which also shapes the structure of mantle flow. First, we test different prescribed viscosity structures inferred from mineral physics. While the match between observed and predicted spectrum is a matter of improvement, these models reproduce Venus' strong geoid-topography correlation. Furthermore, these models support the idea of no, respectively, a small viscosity contrast between upper and lower mantle - in contrast to Earth. Second, we test self-consistently calculated viscosity structures based on an Arrhenius law, which include lateral viscosity variations. These cases lead to a stable degree 3-structure as observed, if convective vigor is sufficiently high. However, comparison of viscosity structures with and without lateral variation indicates that the long-wavelength components of the spectrum are basically insensitive to the lateral variations, which do not improve the fit between observed and predicted spectra. In order to further address this discrepancy, we test models that include a crustal layer and spatial variations in its thickness in the next step.

  11. BOOK REVIEW: June 8, 2004: Venus in Transit

    NASA Astrophysics Data System (ADS)

    Maor, Eli

    2000-09-01

    A transit of Venus is a relatively rare astronomical event in which the silhouette of Venus is seen to move across the face of the Sun. The phenomenon typically lasts several hours, during which Venus is seen as a small dot against the half-degree angular diameter of the solar disc. The last transit of Venus occurred in 1882; the next will be 8 June 2004. Such transits were once of great importance in astronomy. By observing a transit simultaneously from well separated points on the Earth's surface, astronomers were able to measure, with some degree of accuracy, the crucially important separation of the Earth and the Sun. Knowing this enabled them to convert the relative spacings of the planets indicated by Kepler's laws into absolute interplanetary distances expressed in miles or kilometres. Eli Maor's book presents the general reader with a full account of Venusian transits that covers the history of their observation as well as their significance and the reasons for their rarity. The book is a light and enjoyable read that opens well with an imaginative description of observing the 2004 transit from the hills outside Jerusalem. Following an account of Kepler's prediction of a transit of Mercury in 1631 and its observation by Gassendi, the book moves on to describe the transit of Venus in 1639, giving particular emphasis to the prescient work of Jeremiah Horrocks, the extraordinary young English curate and astronomer who died just two years later at the age of 21. The story, however, really takes off with Edmond Halley's realization, in 1677, that transits of Venus might provide the key to determining distances within the solar system. The details of Halley's method are confined to an appendix, but the central chapters of the book detail the increasingly elaborate efforts that astronomers made to observe transits of Venus up to the time of the 1882 transit, when, due to the impact of new photographic methods, interest in transit observations was waning. By that time the distance to the Sun was known to be about 93 000 000 miles and observations of Mars or the asteroids seemed to offer a better prospect of improved accuracy than further observations of Venus. The story is rounded off by a chapter that describes spurious transit observations (such as that of Vulcan, a planet that was supposed to orbit closer to the Sun than Mercury) and a chapter concerning transits of the Earth seen from Mars, Jupiter and the other outer planets. Maor, who is also the author ofe: The Story of a Number, and various other books, writes clearly and well, but Venus in Transit is not uniformly interesting throughout. The early chapters are generally very good, as is the account of Captain James Cook and theEndeavour's voyage to observe the 1761 transit. But after that I felt my interest flagging somewhat, just as the astronomers of the time seemed to find their own interest diminishing. The closing chapters helped to re-engage my interest, but I did feel that the discussion of the 19th century transits was rather perfunctory and that it would have benefited from more space. Still, these are minor criticisms of a book that I am personally very glad to have read. Venus in Transit will obviously appeal most to those with an interest in astronomy, particularly in its historical aspects. But there is also much that physicists can enjoy in the book and I can easily imagine it as a useful though non-essential addition to many school and college libraries. Robert Lambourne

  12. Pioneer Venus 12.5 km Anomaly Workshop Report, volume 1

    NASA Technical Reports Server (NTRS)

    Seiff, A.; Sromovsky, L.; Borucki, W.; Craig, R.; Juergens, D.; Young, R. E.; Ragent, B.

    1995-01-01

    A workshop was convened at Ames Research Center on September 28 and 29, 1993, to address the unexplained electrical anomalies experienced in December 1978 by the four Pioneer Venus probes below a Venus altitude of 12.5 km. These anomalies caused the loss of valuable data in the deep atmosphere, and, if their cause were to remain unexplained, could reoccur on future Venus missions. The workshop participants reviewed the evidence and studied all identified mechanisms that could consistently account for all observed anomalies. Both hardware problems and atmospheric interactions were considered. Based on a workshop recommendation, subsequent testing identified the cause as being an insulation failure of the external harness. All anomalous events are now explained.

  13. Abstracts for the Venus Geoscience Tutorial and Venus Geologic Mapping Workshop

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Abstracts and tutorial are presented from the workshop. Representative titles are: Geology of Southern Guinevere Planitia, Venus, Based on Analyses of Goldstone Radar Data; Tessera Terrain: Characteristics and Models of Origin; Venus Volcanism; Rate Estimates from Laboratory Studies of Sulfur Gas-Solid Reactions; and A Morphologic Study of Venus Ridge Belts.

  14. Abstracts for the venus geoscience tutorial and venus geologic mapping workshop

    SciTech Connect

    Not Available

    1989-01-01

    Abstracts and tutorial are presented from the workshop. Representative titles are: Geology of Southern Guinevere Planitia, Venus, Based on Analyses of Goldstone Radar Data; Tessera Terrain: Characteristics and Models of Origin; Venus Volcanism; Rate Estimates from Laboratory Studies of Sulfur Gas-Solid Reactions; and A Morphologic Study of Venus Ridge Belts.

  15. Upstream proton cyclotron waves at Venus near solar maximum

    NASA Astrophysics Data System (ADS)

    Delva, M.; Bertucci, C.; Volwerk, M.; Lundin, R.; Mazelle, C.; Romanelli, N.

    2015-01-01

    magnetometer data of Venus Express are analyzed for the occurrence of waves at the proton cyclotron frequency in the spacecraft frame in the upstream region of Venus, for conditions of rising solar activity. The data of two Venus years up to the time of highest sunspot number so far (1 Mar 2011 to 31 May 2012) are studied to reveal the properties of the waves and the interplanetary magnetic field (IMF) conditions under which they are observed. In general, waves generated by newborn protons from exospheric hydrogen are observed under quasi- (anti)parallel conditions of the IMF and the solar wind velocity, as is expected from theoretical models. The present study near solar maximum finds significantly more waves than a previous study for solar minimum, with an asymmetry in the wave occurrence, i.e., mainly under antiparallel conditions. The plasma data from the Analyzer of Space Plasmas and Energetic Atoms instrument aboard Venus Express enable analysis of the background solar wind conditions. The prevalence of waves for IMF in direction toward the Sun is related to the stronger southward tilt of the heliospheric current sheet for the rising phase of Solar Cycle 24, i.e., the "bashful ballerina" is responsible for asymmetric background solar wind conditions. The increase of the number of wave occurrences may be explained by a significant increase in the relative density of planetary protons with respect to the solar wind background. An exceptionally low solar wind proton density is observed during the rising phase of Solar Cycle 24. At the same time, higher EUV increases the ionization in the Venus exosphere, resulting in higher supply of energy from a higher number of newborn protons to the wave. We conclude that in addition to quasi- (anti)parallel conditions of the IMF and the solar wind velocity direction, the higher relative density of Venus exospheric protons with respect to the background solar wind proton density is the key parameter for the higher number of observable proton cyclotron waves near solar maximum.

  16. Aeolian abrasion on Venus: Preliminary results from the Venus simulator

    NASA Technical Reports Server (NTRS)

    Marshall, J. R.; Greeley, Ronald; Tucker, D. W.; Pollack, J. B.

    1987-01-01

    The role of atmospheric pressure on aeolian abrasion was examined in the Venus Simulator with a constant temperature of 737 K. Both the rock target and the impactor were fine-grained basalt. The impactor was a 3 mm diameter angular particle chosen to represent a size of material that is entrainable by the dense Venusian atmosphere and potentially abrasive by virtue of its mass. It was projected at the target 10 to the 5 power times at a velocity of 0.7 m/s. The impactor showed a weight loss of approximately 1.2 x 10 to the -9 power gm per impact with the attrition occurring only at the edges. Results from scanning electron microscope analysis, profilometry, and weight measurement are summarized. It is concluded that particles can incur abrasion at Venusian temperatures even with low impact velocities expected for Venus.

  17. International shipment of light weight radioisotopic heater units (LWRHU) using the USA/9516/B(U)F Mound 1 kW shipping package in support of the 'Pluto Express' mission

    SciTech Connect

    Barklay, Chadwick D.; Merten, C. William

    1997-01-10

    Radioisotopes have provided heat that has been used to maintain specific operating environments within remote satellites and spacecraft. For the 'Pluto Express' mission the {sup 238}PuO{sub 2} fueled light weight radioisotopic heater unit (LWRHU) will be used within the spacecraft. Since the current plan for the 'Pluto Express' mission incorporates the use of a Russian launch platform for the spacecraft, the LWRHUs must be transported in an internationally certified shipping container. An internationally certified shipping package that is versatile enough to be reconfigured to transport the LWRHUs that will be required to support the 'Pluto Express' mission is the Mound USA/9516/B(U)F.

  18. A migratory mantle plume on Venus: Implications for Earth?

    USGS Publications Warehouse

    Chapman, M.G.; Kirk, R.L.

    1996-01-01

    A spatially fixed or at least internally rigid hotspot reference frame has been assumed for determining relative plate motions on Earth. Recent 1:5,000,000 scale mapping of Venus, a planet without terrestrial-style plate tectonics and ocean cover, reveals a systematic age and dimensional progression of corona-like arachnoids occurring in an uncinate chain. The nonrandom associations between arachnoids indicate they likely formed from a deep-seated mantle plume in a manner similar to terrestrial hotspot features. However, absence of expected convergent "plate" margin deformation suggests that the arachnoids are the surface expression of a migratory mantle plume beneath a stationary surface. If mantle plumes are not stationary on Venus, what if any are the implications for Earth?

  19. Venus as a more Earth-like planet.

    PubMed

    Svedhem, Håkan; Titov, Dmitry V; Taylor, Fredric W; Witasse, Olivier

    2007-11-29

    Venus is Earth's near twin in mass and radius, and our nearest planetary neighbour, yet conditions there are very different in many respects. Its atmosphere, mostly composed of carbon dioxide, has a surface temperature and pressure far higher than those of Earth. Only traces of water are found, although it is likely that there was much more present in the past, possibly forming Earth-like oceans. Here we discuss how the first year of observations by Venus Express brings into focus the evolutionary paths by which the climates of two similar planets diverged from common beginnings to such extremes. These include a CO2-driven greenhouse effect, erosion of the atmosphere by solar particles and radiation, surface-atmosphere interactions, and atmospheric circulation regimes defined by differing planetary rotation rates. PMID:18046393

  20. Remote sensing of Mars' ionosphere and solar wind interaction - Lessons from Venus

    NASA Astrophysics Data System (ADS)

    Luhmann, J. G.; Kliore, A.; Barnes, A.; Brace, L.

    Although the Phobos spacecraft will make some limited in situ measurements of Mars' upper ionosphere during its transfer orbits, the major part of the mission will be limited to remote sensing by radio occultation and topside sounding methods. To 'calibrate' the former as a means of studying the ionosphere and solar wind interaction, the Pioneer Venus Orbiter radio occultation experiment results are examined in light of what is known from in situ plasma and magnetic field data. This calibration can be used to reassess the data from previous Mars missions and to provide a basis for interpreting data from the upcoming Phobos mission.

  1. Venus transits - A French view

    NASA Astrophysics Data System (ADS)

    Débarbat, Suzanne

    2005-04-01

    After a careful study of Mars observations obtained by Tycho Brahé (1546-1601), Kepler (1571-1630) discovered the now-called Kepler's third law. In 1627 he published his famous Tabulae Rudolphinae, a homage to his protector Rudolph II (1552-1612), tables (Kepler 1609, 1627) from which he predicted Mercury and Venus transits over the Sun. In 1629 Kepler published his Admonitio ad Astronomos Advertisement to Astronomers (Kepler 1630), Avertissement aux Astronomes in French Au sujet de phénomènes rares et étonnants de l'an 1631: l'incursion de Vénus et de Mercure sur le Soleil. This was the beginning of the interest of French astronomers, among many others, in such transits, mostly for Venus, the subject of this paper in which dates are given in the Gregorian calendar.

  2. How the Venus flytrap snaps

    NASA Astrophysics Data System (ADS)

    Forterre, Yoël; Skotheim, Jan M.; Dumais, Jacques; Mahadevan, L.

    2005-01-01

    The rapid closure of the Venus flytrap (Dionaea muscipula) leaf in about 100ms is one of the fastest movements in the plant kingdom. This led Darwin to describe the plant as ``one of the most wonderful in the world''. The trap closure is initiated by the mechanical stimulation of trigger hairs. Previous studies have focused on the biochemical response of the trigger hairs to stimuli and quantified the propagation of action potentials in the leaves. Here we complement these studies by considering the post-stimulation mechanical aspects of Venus flytrap closure. Using high-speed video imaging, non-invasive microscopy techniques and a simple theoretical model, we show that the fast closure of the trap results from a snap-buckling instability, the onset of which is controlled actively by the plant. Our study identifies an ingenious solution to scaling up movements in non-muscular engines and provides a general framework for understanding nastic motion in plants.

  3. Solar wind absorption by Venus

    NASA Technical Reports Server (NTRS)

    Gombosi, T. I.; Cravens, T. E.; Nagy, A. F.; Elphic, R. C.; Russell, C. T.

    1980-01-01

    The portion of solar wind interacting with the dayside ionosphere and atmosphere of Venus was determined based on magnetic field fluctuations in the ionosheath and the interaction with the upper neutral atmosphere above the ionopause. Fluctuations with the ratio of the number of particles intersecting the daytide ionopause to the total number of particles of 0.3 suggest that about 0.3% of solar wind may be absorbed. Most of fast H atoms resulting from the charge exchange interactions with the atmosphere escape; some of the energy deposition processes produce observable signatures (such as a narrow Lyman alpha emission region), but penetrating solar wind particles do not control the physical and/or chemical structure of the daytime Venus ionosphere.

  4. Memristors in the Venus flytrap.

    PubMed

    Volkov, Alexander G; Forde-Tuckett, Victoria; Reedus, Jada; Mitchell, Colee M; Volkova, Maya I; Markin, Vladislav S; Chua, Leon

    2014-01-01

    A memristor is a nonlinear element because its current-voltage characteristic is similar to that of a Lissajous pattern for nonlinear systems. We investigated the possible presence of memristors in the electrical circuitry of the Venus flytrap's upper and lower leaves. The electrostimulation of this plant by bipolar sinusoidal or triangle periodic waves induces electrical responses in the upper and lower leaves of the Venus flytrap with fingerprints of memristors. The analysis was based on cyclic voltammetric characteristics where the memristor, a resistor with memory, should manifest itself. Tetraethylammonium chloride, an inhibitor of voltage gated K(+) channels, or NPPB, a blocker of voltage gated Cl(-) and K(+) channels, transform a memristor to a resistor in plant tissue. Uncouplers carbonylcyanide-3-chlorophenylhydrazone (CCCP) and carbonylcyanide-4-trifluoromethoxy-phenyl hydrazone (FCCP) decrease the amplitude of electrical responses at low and high frequencies of bipolar periodic electrostimulating waves. Our results demonstrate that voltage gated K(+) channels in the Venus flytrap have properties of memristors of type 1 and type 2. The discovery of memristors in plants creates a new direction in the modeling and understanding of electrical phenomena in plants. PMID:25763613

  5. Memristors in the Venus flytrap.

    PubMed

    Volkov, Alexander G; Forde-Tuckett, Victoria; Reedus, Jada; Mitchell, Colee M; Volkova, Maya I; Markin, Vladislav S; Chua, Leon

    2014-05-16

    A memristor is a nonlinear element because its current-voltage characteristic is similar to that of a Lissajous pattern for nonlinear systems. We investigated the possible presence of memristors in the electrical circuitry of the Venus flytrap's upper and lower leaves. The electrostimulation of this plant by bipolar sinusoidal or triangle periodic waves induces electrical responses in the upper and lower leaves of the Venus flytrap with fingerprints of memristors. The analysis was based on cyclic voltammetric characteristics where the memristor, a resistor with memory, should manifest itself. Tetraethylammonium chloride, an inhibitor of voltage gated K(+) channels, or NPPB, a blocker of voltage gated Cl(-) and K(+) channels, transform a memristor to a resistor in plant tissue. Uncouplers carbonylcyanide-3-chlorophenylhydrazone (CCCP) and carbonylcyanide-4-trifluoromethoxy-phenyl hydrazone (FCCP) decrease the amplitude of electrical responses at low and high frequencies of bipolar periodic electrostimulating waves. Our results demonstrate that voltage gated K(+) channels in the Venus flytrap have properties of memristors of type 1 and type 2. The discovery of memristors in plants creates a new direction in the modeling and understanding of electrical phenomena in plants. PMID:24837439

  6. Memristors in the Venus flytrap

    PubMed Central

    Volkov, Alexander G; Forde-Tuckett, Victoria; Reedus, Jada; Mitchell, Colee M; Volkova, Maya I; Markin, Vladislav S.; Chua, Leon

    2014-01-01

    A memristor is a nonlinear element because its current-voltage characteristic is similar to that of a Lissajous pattern for nonlinear systems. We investigated the possible presence of memristors in the electrical circuitry of the Venus flytrap’s upper and lower leaves. The electrostimulation of this plant by bipolar sinusoidal or triangle periodic waves induces electrical responses in the upper and lower leaves of the Venus flytrap with fingerprints of memristors. The analysis was based on cyclic voltammetric characteristics where the memristor, a resistor with memory, should manifest itself. Tetraethylammonium chloride, an inhibitor of voltage gated K+ channels, or NPPB, a blocker of voltage gated Cl- and K+ channels, transform a memristor to a resistor in plant tissue. Uncouplers carbonylcyanide-3-chlorophenylhydrazone (CCCP) and carbonylcyanide-4-trifluoromethoxy-phenyl hydrazone (FCCP) decrease the amplitude of electrical responses at low and high frequencies of bipolar periodic electrostimulating waves. Our results demonstrate that voltage gated K+ channels in the Venus flytrap have properties of memristors of type 1 and type 2. The discovery of memristors in plants creates a new direction in the modeling and understanding of electrical phenomena in plants. PMID:25763613

  7. Deduction of Vertical Temperature Profiles on Mars and Venus from Ground-Based Heterodyne Observations at 10?m

    NASA Astrophysics Data System (ADS)

    Stangier, T.; Sonnabend, G.; Herrmann, M.; Sornig, M.

    2013-09-01

    We report on the retrieval of vertical temperature distributions in the atmosphere of Mars and Venus by analyzing ultra highly resolved CO2 absorption features, acquired by ground-based observations at 10 ?m. Preliminary results from the retrievals will be presented and compared to model predictions from the Mars Climate Database (MCD). In addition results from coordinated measuring campaigns with the Venus Express Radio Science Experiment (VeRa).

  8. Venus Water Vapour Profiles Obtained by SOIR/VEx

    NASA Astrophysics Data System (ADS)

    Chamberlain, Sarah; Wilquet, Valerie; Mahieux, Arnaud; Robert, Severine; Thomas, Ian; Carine Vandaele, Ann; Bertaux, Jean-Loup

    2015-04-01

    We present up-to-date observations of the water vapour profile at the Venus terminator, between altitudes of 70 - 110km. The data were obtained by the Solar Occultation in the InfraRed (SOIR) instrument on board Venus Express (VEx). The SOIR instrument allows observations of trace gas profiles at altitudes within the Venus lower thermosphere and mesosphere. Due to the observational technique, all observations are taken at the Venus terminator, on either or both of the evening and morning side of the planet and covering almost all latitudes. These are key locations for study as the mesosphere/thermosphere altitudes correspond to the transition in dynamical regime from a retrograde zonal flow to sub-solar to antisolar flow (approximately 90 km) and at these altitudes we expect a steeper than normal temperature gradient across the terminator which would drive chemical reactions and dynamical flows. Water vapour in the mesosphere is involved in the cloud formation process and contributes to several chemical cycles. Isotopologue ratio studies also contribute towards understanding the evolution of the Venus climate and atmosphere. Determining the abundance, distribution and variability of water vapour is therefore a key element to understanding the development, maintenance and links between dynamical features, important chemical cycles and the evolution of the Venus atmosphere. Both water vapour isotopologues are targeted simultaneously in the majority of dedicated SOIR water vapour observations. H2O is detected between 70 - 110km and HDO is detected between 70 - 95km altitude. Early SOIR water vapour observations were published in 2007 and 2008. Previous results show a depletion in the volume mixing ratio (VMR) at 85km in both HDO and H2O and an increase in HDO/H2O ratio above the clouds. No noticeable temporal variability was detected. Numerous subsequent H2O and HDO SOIR observations have been obtained between 2007 - 2014 and with recent improvements in instrument calibration, data reduction and a long base line of data, a new analysis has become pertinent.

  9. Novel Architecture for a Long-Life, Lightweight Venus Lander

    SciTech Connect

    Bugby, D.; Seghi, S.; Kroliczek, E.; Pauken, M.

    2009-03-16

    This paper describes a novel concept for an extended lifetime, lightweight Venus lander. Historically, to operate in the 480 deg. C, 90 atm, corrosive, mostly CO{sub 2} Venus surface environment, previous landers have relied on thick Ti spherical outer shells and thick layers of internal insulation. But even the most resilient of these landers operated for only about 2 hours before succumbing to the environment. The goal on this project is to develop an architecture that extends lander lifetime to 20-25 hours and also reduces mass compared to the Pioneer Venus mission architecture. The idea for reducing mass is to: (a) contain the science instruments within a spherical high strength lightweight polymer matrix composite (PMC) tank; (b) surround the PMC tank with an annular shell of high performance insulation pre-pressurized to a level that (after landing) will exceed the external Venus surface pressure; and (c) surround the insulation with a thin Ti outer shell that contains only a net internal pressure, eliminating buckling overdesign mass. The combination of the PMC inner tank and thin Ti outer shell is lighter than a single thick Ti outer shell. The idea for extending lifetime is to add the following three features: (i) an expendable water supply that is placed within the insulation or is contained in an additional vessel within the PMC tank; (ii) a thin spherical evaporator shell placed within the insulation a short radial distance from the outer shell; and (iii) a thin heat-intercepting liquid cooled shield placed inboard of the evaporator shell. These features lower the temperature of the insulation below what it would have been with the insulation alone, reducing the internal heat leak and lengthening lifetime. The use of phase change materials (PCMs) inside the PMC tank is also analyzed as a lifetime-extending design option. The paper describes: (1) analytical modeling to demonstrate reduced mass and extended life; (2) thermal conductivity testing of high performance insulation as a function of temperature and pressure; (3) a bench-top ambient pressure thermal test of the evaporation system; and (4) a higher fidelity test, to be conducted in a high pressure, high temperature inert gas test chamber, of a small-scale Venus lander prototype (made from two hemispherical interconnecting halves) that includes all of the aforesaid features.22 CFR 125.4(b)(13) applicable.

  10. Novel Architecture for a Long-Life, Lightweight Venus Lander

    NASA Astrophysics Data System (ADS)

    Bugby, D.; Seghi, S.; Kroliczek, E.; Pauken, M.

    2009-03-01

    This paper describes a novel concept for an extended lifetime, lightweight Venus lander. Historically, to operate in the 480° C, 90 atm, corrosive, mostly CO2 Venus surface environment, previous landers have relied on thick Ti spherical outer shells and thick layers of internal insulation. But even the most resilient of these landers operated for only about 2 hours before succumbing to the environment. The goal on this project is to develop an architecture that extends lander lifetime to 20-25 hours and also reduces mass compared to the Pioneer Venus mission architecture. The idea for reducing mass is to: (a) contain the science instruments within a spherical high strength lightweight polymer matrix composite (PMC) tank; (b) surround the PMC tank with an annular shell of high performance insulation pre-pressurized to a level that (after landing) will exceed the external Venus surface pressure; and (c) surround the insulation with a thin Ti outer shell that contains only a net internal pressure, eliminating buckling overdesign mass. The combination of the PMC inner tank and thin Ti outer shell is lighter than a single thick Ti outer shell. The idea for extending lifetime is to add the following three features: (i) an expendable water supply that is placed within the insulation or is contained in an additional vessel within the PMC tank; (ii) a thin spherical evaporator shell placed within the insulation a short radial distance from the outer shell; and (iii) a thin heat-intercepting liquid cooled shield placed inboard of the evaporator shell. These features lower the temperature of the insulation below what it would have been with the insulation alone, reducing the internal heat leak and lengthening lifetime. The use of phase change materials (PCMs) inside the PMC tank is also analyzed as a lifetime-extending design option. The paper describes: (1) analytical modeling to demonstrate reduced mass and extended life; (2) thermal conductivity testing of high performance insulation as a function of temperature and pressure; (3) a bench-top ambient pressure thermal test of the evaporation system; and (4) a higher fidelity test, to be conducted in a high pressure, high temperature inert gas test chamber, of a small-scale Venus lander prototype (made from two hemispherical interconnecting halves) that includes all of the aforesaid features. 22 CFR 125.4(b)(13) applicable

  11. The Pioneer Missions

    NASA Technical Reports Server (NTRS)

    Lasher, Larry E.; Hogan, Robert (Technical Monitor)

    1999-01-01

    This article describes the major achievements of the Pioneer Missions and gives information about mission objectives, spacecraft, and launches of the Pioneers. Pioneer was the United States' longest running space program. The Pioneer Missions began forty years ago. Pioneer 1 was launched shortly after Sputnik startled the world in 1957 as Earth's first artificial satellite at the start of the space age. The Pioneer Missions can be broken down into four distinct groups: Pioneer (PN's) 1 through 5, which comprise the first group - the "First Pioneers" - were launched from 1958 through 1960. These Pioneers made the first thrusts into space toward the Moon and into interplanetary orbit. The next group - the "Interplanetary Pioneers" - consists of PN's 6 through 9, with the initial launch being in 1965 (through 1968); this group explored inward and outward from Earth's orbit and travel in a heliocentric orbit around the Sun just as the Earth. The Pioneer group consisting of 10 and 11 - the "Outer Solar System Pioneers" - blazed a trail through the asteroid belt and was the first to explore Jupiter, Saturn and the outer Solar System and is seeking the borders of the heliosphere and will ultimately journey to the distant stars. The final group of Pioneer 12 and 13 the "Planetary Pioneers" - traveled to Earth's mysterious twin, Venus, to study this planet.

  12. Tidal constraints on the interior of Venus

    NASA Astrophysics Data System (ADS)

    Dumoulin, C.; Tobie, G.; Verhoeven, O.; Rosenblatt, P.; Rambaux, N.

    2015-10-01

    As a prospective study for a future exploration of Venus, we propose to systematically investigate the signature of the internal structure in the gravity field and the rotation state of Venus, through the determination of the moment of inertia and the tidal Love number.

  13. Basalt-Atmosphere Interactions on Venus -

    E-