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Sample records for venus express mission

  1. Missions to Venus

    NASA Astrophysics Data System (ADS)

    Titov, D. V.; Baines, K. H.; Basilevsky, A. T.; Chassefiere, E.; Chin, G.; Crisp, D.; Esposito, L. W.; Lebreton, J.-P.; Lellouch, E.; Moroz, V. I.; Nagy, A. F.; Owen, T. C.; Oyama, K.-I.; Russell, C. T.; Taylor, F. W.; Young, R. E.

    2002-10-01

    Venus has always been a fascinating objective for planetary studies. At the beginning of the space era Venus became one of the first targets for spacecraft missions. Our neighbour in the solar system and, in size, the twin sister of Earth, Venus was expected to be very similar to our planet. However, the first phase of Venus spacecraft exploration in 1962-1992 by the family of Soviet Venera and Vega spacecraft and US Mariner, Pioneer Venus, and Magellan missions discovered an entirely different, exotic world hidden behind a curtain of dense clouds. These studies gave us a basic knowledge of the conditions on the planet, but generated many more questions concerning the atmospheric composition, chemistry, structure, dynamics, surface-atmosphere interactions, atmospheric and geological evolution, and the plasma environment. Despite all of this exploration by more than 20 spacecraft, the "morning star" still remains a mysterious world. But for more than a decade Venus has been a "forgotten" planet with no new missions featuring in the plans of the world space agencies. Now we are witnessing the revival of interest in this planet: the Venus Orbiter mission is approved in Japan, Venus Express - a European orbiter mission - has successfully passed the selection procedure in ESA, and several Venus Discovery proposals are knocking at the doors of NASA. The paper presents an exciting story of Venus spacecraft exploration, summarizes open scientific problems, and builds a bridge to the future missions.

  2. Venus winds at cloud level from VIRTIS during the Venus Express mission

    NASA Astrophysics Data System (ADS)

    Hueso, Ricardo; Peralta, Javier; Sánchez-Lavega, Agustín.; Pérez-Hoyos, Santiago; Piccioni, Giuseppe; Drossart, Pierre

    2010-05-01

    The Venus Express (VEX) mission has been in orbit to Venus for almost four years now. The VIRTIS instrument onboard VEX observes Venus in two channels (visible and infrared) obtaining spectra and multi-wavelength images of the planet. Images in the ultraviolet range are used to study the upper cloud at 66 km while images in the infrared (1.74 μm) map the opacity of the lower cloud deck at 48 km. Here we present our latest results on the analysis of the global atmospheric dynamics at these cloud levels using a large selection over the full VIRTIS dataset. We will show the atmospheric zonal superrotation at these levels and the mean meridional motions. The zonal winds are very stable in the lower cloud at mid-latitudes to the tropics while it shows different signatures of variability in the upper cloud where solar tide effects are manifest in the data. While the upper clouds present a net meridional motion consistent with the upper branch of a Hadley cell the lower cloud present almost null global meridional motions at all latitudes but with particular features traveling both northwards and southwards in a turbulent manner depending on the cloud morphology on the observations. A particular important atmospheric feature is the South Polar vortex which might be influencing the structure of the zonal winds in the lower cloud at latitudes from the vortex location up to 55°S. Acknowledgements This work has been funded by the Spanish MICIIN AYA2009-10701 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  3. 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.

  4. 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…

  5. 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.

  6. Questions About Venus after Venus Express

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay

    2016-04-01

    The observations from Venus Express for nearly 13 Venus years or 26 solar days from April 2006 till 27 November 2014. Earlier, Venus has been explored by fly-by spacecraft, orbiters, descending probes, landers and floating balloons. These data have been supplemented by many ground based observations at reflected solar wavelengths, short and long wave infrared, millimeter to radio waves. Venus Express added significantly to the collection that will continue to be examined for understanding the planet's atmosphere and continuing analysis will inform us about new facets of the atmosphere and raise new questions. Inter-comparison of the measurements have been able to provide a 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(s) in the cloud layer, and wind speed and direction near the surface from equator to the pole, interaction between the atmosphere and the solid planet. The answers to these questions are important for a better understanding of Venus, its weather and climate and how the climate has evolved. The questions include: (i) What are the implications of the supercritical state of the two primary constituents of the Venus atmosphere - carbon dioxide and nitrogen in the lower atmosphere? (ii) Is the Venus (lower) atmosphere well mixed? (iii) What determines the observed alternating stable and unstable layers (static stability) in the lower atmosphere? (iv) What causes the contrasts seen in reflected sunlight which are largest at ultraviolet wavelengths and very muted at other visible wavelengths? (v) what causes the morning -afternoon

  7. Future Venus exploration: mission Venera-D

    NASA Astrophysics Data System (ADS)

    Zasova, Ludmila

    Venus was actively studied by Soviet and US missions in 60-90-th years of the last century. The investigations carried out both from the orbit and in situ were highly successful. After a 15-year break in space research of Venus, the ESA Venus Express mission, launched in 2005, successfully continues its work on orbit around Venus, obtaining spectacular results. However, many questions concerning the structure and evolutions of the planet Venus, which are the key questions of comparative planetology and very essential for understanding the possible evolution of the terrestrial climate, cannot be solved by observations only from an orbit. Venera-D includes orbiter, lander, subsatellite, long living station on the surface. Venera-D is focused for both in situ and remote investigations of Venus of surface and atmosphere, as well plasma environment and solar wind interaction. Practically all experiments for Venera-D, will be provided by international teams. A Russia-US Venera-D Joint Science Definition Team has been formed in February 2014 to recommend a possible collaborative and coordinated implementation by considering the common aspects of Venera-D mission as presently defined, as well as the Venus Climate Mission recommended by the US Academies Decadal Survey of Planetary Science and the Venus Flagship mission studied by NASA in 2009. The team will provide its report by March 2015 and will likely lead to a coordinated or joint call for instruements and/or mission elements.

  8. Japan launches mission to Venus

    NASA Astrophysics Data System (ADS)

    Banks, Michael

    2010-06-01

    The Japanese space agency JAXA has launched its first mission to Venus. The Akatsuki craft, which means "dawn" in Japanese, took off last month from the Tanegashima Space Center on the island of Kagoshima, south-west of mainland Japan.

  9. Results from VIRTIS on board Venus Express after the end of the mission operations

    NASA Astrophysics Data System (ADS)

    Piccioni, G.; Drossart, P.; VIRTIS Venus Express team

    After more than 8 years since the orbit insertion, the Venus Express mission is now at its end of mission operations. VIRTIS aboard the Venus Express spacecraft has addressed a significant amount of scientific results from the surface up to the upper atmosphere, in terms of mapping, composition, structure and dynamics. The VIRTIS instrument consists of two channels: VIRTIS-M, an imaging spectrometer with moderate spectral resolution in the range from 0.25 to 5.2 mu m and VIRTIS-H, a high spectral resolution spectrometer in the range from 2 to 5 mu m co-aligned with the field of view of –M \\citep{Piccioni2007a,Drossart2007a}. The resolution of VIRTIS-M is 2 nm from 0.25 to 1 mu m, and 10 nm from 1 to 5.2 mu m. The resolution of VIRTIS-H is about 2 nm. The atmosphere above the clouds has been observed both on day and night sides, in solar reflection and thermal emission in nadir geometry \\citep{Ignatiev2009, Cottini2012, Peralta2012, Peralta2009}. Limb observations provided O2\\citep{Piccioni2009, Garcia2009a, Gerard2013, Migliorini2013a, Gerard2008, Gerard2009}, OH \\citep{Piccioni2008,Gerard2010,Soret2010,Soret2012}, NO \\citep{Garcia2009b}, CO2 \\citep{Drossart2007b,Lopez-Valverde2011} and CO \\citep{Gilli2009,Gilli2015,Gilli2011} emissions, through nightglow and fluorescence observations. Spectroscopy of the 4-5 mu m range gave access to the cloud structure in the 60-95 km altitude levels \\citep{Irwin2008a,Grassi2014, Grassi2008,Grassi2010,Luz2011}. The deeper atmospheric windows, limited by CO2 and H2O bands were accessible only in thermal emission on the night side. The sounded levels at 1.7 and 2.3 mu m were limited respectively to 30-20 km altitude \\citep{Barstow2012,Bezard2009,Marcq2008a,Satoh2009,Tsang2009, Tsang2010,Tsang2008,Wilson2008,Wilson2009}, while at shorter wavelengths (1.18, 1.10, 1.01, 0.9 and 0.85 mu m), the hot surface of Venus was seen through the scattering clouds \\citep{Mueller2009,Helbert2008,Arnold2008a,Smrekar2010,Mueller2012

  10. Mars and Venus - The Express Way : Evolution and Heritage in Flexi Type Missions Concerning Model Philosophy and Environmental Test Design

    NASA Astrophysics Data System (ADS)

    Rustichelli, S.; McCoy, D.; Florino, T.; Pereira, J.; Pendaries, M.

    2004-08-01

    Mars Express is the first example of ESA's "Flexible Missions", a new and more economic way of building space science missions based on maximum use of existing technology that is either 'off-the-shelf' or technology that has already been developed for other programs. The high level of recurrence in the design, the re-use of existing hardware and the implementation of new project management practices made possible to Mars Express to meet the objective of shortening the time from original concept to launch, being built unusually quickly to meet its narrow launch window in June 2003. The objective of being assembled, fully tested and prepared for launch in a record time, 30% faster than other comparable missions and with reduced financial funding, could be achieved only with a thorough re- thinking of the model philosophy and environmental test design. The encouraging results obtained with Mars Express are the basis of the AIV program of the second ESA's Flexible Mission, Venus Express. Highly recurrent of Mars Express, even if with important peculiarities due to the different mission and planetary environment, this Project will benefit of the qualifications achieved on its predecessor, allowing a single module approach where the AIT campaign will start directly on the PFM. This paper presents the innovative concepts implemented in the definition of Mars Express Model Philosophy and Environmental Test campaigns, showing the influence of the adopted solutions on the in-flight performances. An overview of Venus Express Test Campaign is also given, focusing on the effects of the previous experience and the lessons learned as well as the peculiarities of the new mission.

  11. The Role of Different Parameters in the Pressurant Budget of Venus Express and its Dynamic Evolution during the Mission

    NASA Astrophysics Data System (ADS)

    Valencia Bel, F.; Lang, M.

    2004-10-01

    An insufficient amount of pressurant gas in the propulsion system or a working temperature in the pressurant tank outside the qualification limits can cause a decrease in the performance of the thrusters or even the loss of the mission. This paper presents an engineering tool used able to compute the Pressurant budget of a mission and the effects of influencing parameters. The updated tool allows to also compute the temperature, pressure and mass evolution inside the pressurant tank during the various mission phases. The tool has been used to verify the calculations done by Astrium Stevenage for Mars Express and Venus Express [1]. The pressurant gas used for both cases was helium. The tool permits to use other combinations of pressurant gases and propellants for different propellant systems (monopropellant and bipropellant systems).

  12. The European Venus Explorer (EVE) mission proposal

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

    The European Venus Explorer (EVE) is a mission proposed to the European Space Agency (ESA) under the Cosmic Vision Call for Ideas, for launch in 2016-2018. The central goal of this mission is to investigate the evolution of Venus and its climate, in order to understand better the 'life cycle' of Earth-like planets everywhere. After the excellent results being obtained from ESA's Venus Express orbiter, in situ measurements will be required to answer many of the outstanding questions, specially relating to the evolution of the planet, its complex cloud chemistry and the stability of its climate. The baseline EVE mission 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 perform science observations as well as relay data from the balloon and descent probe. The minimum lifetime of the balloon is 7 days, required for one full circle around the planet, much longer than the 48 hour data returned from Russia's VEGA balloons. Earth-based VLBI and Doppler measurements provide tracking information for the orbiter, allowing measurement of the variations in the planet's gravity field, and for the balloon and descent probe to yield wind measurements in the lower atmosphere. The descent probe's fall through the atmosphere is expected to last 60 minutes, followed by a lifetime of 30 minutes on the surface. The Japanese space agency (JAXA) also proposes to include another independent platform, a small water vapour-inflated balloon which would be deployed at 35 km altitude and would communicate directly to Earth. Further details of the EVE mission, including proposals for Education & Outreach schemes, can be viewed at the mission website: http://www.aero.jussieu.fr/EVE/

  13. Investigation of planetary space weather effects at Venus observed by the ASPERA-4 particle analyzer and the magnetometer flying onboard of Venus Express Mission

    NASA Astrophysics Data System (ADS)

    Vech, Daniel; Szego, Karoly; Opitz, Andrea; Fraenz, Markus

    2014-05-01

    In this study we identified several coronal mass-ejections (CME's) interacting with the induced magnetosphere of Venus during 2010 and 2011 using STEREO observations and ENLIL simulations. Our purpose is to analyze the response of the induced magnetosphere and the ionosphere to these extreme conditions based on measurements made by the ASPERA-4 and MAG instruments on Venus Express. The parameters of the interplanetary magnetic field (IMF) during these solar events are also discussed. Previously we investigated the effects of the May 2007 solar eruption on the induced magnetosphere of Venus in a poster publication (EPSC2013-266). During the analyzed solar event large scale rotation of the interplanetary magnetic field was observed and in the polar region, the altitude where planetary ions were present decreased compared to the average cases. Polarity reversal of the induced magnetosphere also took place, similar to the cases discussed by Edberg et. al (2011). Several CME's interacted with Venus in November 2011. One of the largest lifted off on 3rd November and reached Venus on 5th November. The solar wind parameters showed large variations: the velocity peaked over 900 km/s, and the magnitude of the IMF suddenly increased threefold. The magnetic field reached 240 nT inside the induced magnetosphere, which is extremely high compared to normal conditions. The heavy ion density measured by VEX peaked over 1000 1/cm3 providing clear evidence for ionosphere crossing. Due to the orbit parameters it is possible to investigate the magnetic structure in the tail. The other selected solar eruptions caused similar changes including the sudden increase in the solar wind velocity and magnitude of the magnetic field in the magnetic barrier but due to the different orbital parameters other regions of the induced magnetosphere were investigated as well. In conclusion the observed planetary space weather effects include that in the shocked solar wind we observed Increased velocity

  14. The Surface of Venus After VIRTIS on Venus Express: Laboratory Analogs and the Venus Emissivity Mapper

    NASA Astrophysics Data System (ADS)

    Ferrari, S.; Helbert, J.; Maturilli, A.; Dyar, D. M.; Mueller, N.; Elkins-Tanton, L. T.

    2014-05-01

    A combination of laboratory work and remote sensing will be able to determine the large-scale compositional variations of the surface of Venus and will provide valuable input for any landing site selections for future Venus lander missions.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. Magnetotellurics at Venus: What Venus Express and Pioneer Venus Tell Us about the Possibility of Electromagnetic Sounding of the Venus Crust

    NASA Astrophysics Data System (ADS)

    Russell, Christopher T.; Zhang, Tielong L.; Baumjohann, Wolfgang; Luhmann, Janet G.; Villarreal, Michaela; Chi, Peter J.

    2016-04-01

    In late 2014, the Venus Express mission was allowed to drop its periapsis altitude into the Venus atmosphere, sufficiently low to penetrate below the maximum electron density of the ionosphere into the neutral atmosphere below. In this paper, we examine the observations in this region and assess if such observations could be used to sound the interior electrical conductivity of Venus. We conclude that the fluctuating field would only be useful for sounding with landers on the surface. However, it might be possible to sound the core using the draped magnetic field, an essentially static signature.

  2. Life after Venus Express: Science goals for a European Venus radar orbiter

    NASA Astrophysics Data System (ADS)

    Wilson, Colin; Ghail, Richard

    ESA’s Venus Express mission has led to a renaissance of Venus science, following a dearth of Venus missions in the previous 15 years. Venus Express has made many discoveries in atmospheric science, for which its payload was optimised; however it has also provided tantalising hints about the geological activity of the planet. Mesospheric sulphur dioxide abundances vary by 1000% on decadal timescales, in a pattern which suggests episodic volcanic injections [Marcq et al. Nature Geosci 2013; Esposito, Science 1984]; anomalous emissivity near suggest volcanic hotspots implies geologically recent, as-yet-unweathered lava flows [Smrekar et al., Science 2010]; and recent results, if confirmed, show temporal evolution of thermal emission from some regions of the surface may be direct evidence of volcanic activity during the duration of the VEx mission [Shalygin et al., LPSC 2014]. While there are more results to be obtained yet from the Venus Express dataset, further investigation of these phenomena will require a new Venus mission. We therefore propose an orbiter mission focussed on characterising the geological activity of Venus. The key instrument would be a Synthetic Aperture Radar (SAR). Why a radar mission following NASA’s Magellan mission? Radar capabilities are vastly improved in the last 30 years and a modern radar would be capable of spatial resolution approaching two orders of magnitude better than that from Magellan; this enables a wide range of investigations, from detailed study of tectonic, volcanic and Aeolian features, to stratigraphy for better reconstruction of geological epochs. Interferometric SAR could also be used to study the centimetre-scale surface deformations due to current volcanic or tectonic activity. Constraints on interior structure can be obtained not only from improved gravity mapping (from spacecraft tracking) but also by studying the spin state of Venus from high-resolution radar measurements. The radar measurements will be

  3. NASA's Venus Science and Technology Definition Team: A Flagship Mission to Venus

    NASA Astrophysics Data System (ADS)

    Bullock, Mark Alan; Senske, D. A.; Balint, T. S.; Campbell, B. A.; Chassefiere, E.; Colaprete, A.; Cutts, J. A.; Glaze, L.; Gorevan, S.; Grinspoon, D. H.; Hall, J.; Hartford, W.; Hashimoto, G. L.; Head, J. W.; Hunter, G.; Johnson, N.; Kiefer, W. S.; Kolawa, E. A.; Kremic, T.; Kwok, J.; Limaye, S. S.; Mackwell, S. J.; Marov, M. Y.; Ocampo, A.; Schubert, G.; Stofan, E. R.; Svedhem, H.; Titov, D. V.; Treiman, A. H.

    2008-09-01

    The Venus Science and Technology Definition Team (STDT) was formed by NASA to look at science objectives, mission architecture, science investigations, and instrument payload for a Flagship-class mission to Venus. This $3-4B mission, to launch in the 2020-2025 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 be capable of resolving the geologic history of Venus, including the existence and persistence of an ancient ocean. Achieving all these objectives will be necessary to understand the habitability of extrasolar terrestrial planets that should be detected in the next few years. The Venus STDT is comprised of scientists and engineers from the United States, the Russian Federation, France, Germany, the Netherlands, and Japan. The team began work in January 2008, gave an interim report at NASA headquarters in May, and will deliver a final report in December 2008. The Venus STDT will also produce a technology roadmap to identify crucial investments to meet the unique challenges of in situ Venus exploration. We will discuss the mission architecture and payload that have been designed to address the science objectives, and the methods we used. Most of the science objectives in the latest VEXAG white paper can be addressed by a Venus Flagship mission, and equally importantly, NASA can fly a large mission to another Earth-sized planet with the explicit intention of better understanding our own.

  4. 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

  5. Venus Upper Atmosphere - Results from the Venus Express Aerobraking Campaign

    NASA Astrophysics Data System (ADS)

    Svedhem, H.

    2015-12-01

    During the last year of operations Venus Express was conducting an experimental aerobraking campaign. The objectives were twofold; firstly, to exercise for the first time the techniques of orbit modification by aerobraking with a European spacecraft, in order to prepare for future scientific ESA missions, and secondly, to collect information on atmospheric density by direct measurements in an environment difficult to sample with other means. Several of the scientific instruments on board Venus Express measured gas abundances of various gasses, including CO2, up to an altitude of 130km, but no reliable measurements could be made of total density and no remote measurements could be done above this altitude. The on board accelerometers gave direct measurements of the deceleration which in turn is directly proportional to the local atmospheric density. This provided an excellent way to study both the total density profile throughout the orbital arc in the atmosphere and small scale density variations in the region of the pericentre. The spacecraft behaved perfectly well throughout the whole campaign and provided a wealth of data both on the atmosphere and on the response of the spacecraft to the harsh environment with strong heat loads and some dynamic stress. At the time of the campaign the pericentre was located near the terminator at about 75 degrees Northern latitude. The so called "walk-in" phase started at an altitude of 190 km on 17 May 2014 and the campaign ended on 11 July, after having reached a lowest altitude of 129.2 km. Subsequently, a series of orbit control manoeuvres lifted up the pericentre to 460 km altitude and the science activities were resumed after a thorough check-out of the spacecraft. We have detected a highly variable atmosphere, both on a day to day basis and within the individual pericentre passes. The duration of each pass was approximately 100 s and the maximum dynamic pressure achieved was more than 0.75 N/m2. The orbital period was

  6. 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.

  7. Visual aid titled 'The Magellan Mission to Venus'

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Visual aid titled 'The Magellan Mission to Venus' describes data that will be collected and science objectives. Images and brightness temperatures will be obtained for 70-90% of the surface, with a radar resolution of 360 meters or better. The global gravity field model will be refined by combining Magellan and Pioneer-Venus doppler data. Altimetry data will be used to measure the topography of 70-90% of the surface with a vertical accuracy of 120-360 meters. Science objectives include: to improve the knowledge of the geological history of Venus by analysis of the surface morphology and electrical properties and the processes that control them; and to improve the knowledge of the geophysics of Venus, principally its density distribution and dynamics. Magellan, named for the 16th century Portuguese explorer, will be deployed from the payload bay (PLB) of Atlantis, Orbiter Vehicle (OV) 104, during mission STS-30.

  8. 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)

  9. Venus O + pickup ions: Collected PVO results and expectations for Venus Express

    NASA Astrophysics Data System (ADS)

    Luhmann, J. G.; Ledvina, S. A.; Lyon, J. G.; Russell, C. T.

    2006-11-01

    Observations of oxygen pickup ions by the plasma analyzer on the Pioneer Venus Orbiter (PVO) Mission arguably launched broad interest in solar wind erosion of unmagnetized planet atmospheres, and its potential evolutionary effects. Oxygen pickup ions may play key roles in the removal of the oxygen excess left behind from the photodissociation of water vapor by enabling direct escape, additional sputtering of oxygen when they impact the exobase, and escape as energetic neutrals produced in charge exchange reactions with the ambient exospheric oxygen and hydrogen. Although the PVO observations were compromised by an ˜8 keV energy limit for O + detection, a lack of ion composition capability, and the limited sampling and data rate of the plasma analyzer which was designed for solar wind monitoring, these measurements provide our best information about the extended O + exosphere and wake at Venus. Here we show the full picture of the spatial distribution and energies of the O + ion observations collected by the plasma analyzer during PVO's ˜5000 orbit tour. A model of O + test particles launched in the circum-Venus fields described by an MHD simulation of the solar wind interaction is used to help interpret the PVO observations and to anticipate the expanded view of Venus O + escape that will be provided by the ASPERA-4 experiment on Venus Express.

  10. 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.

  11. 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.

  12. 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.

  13. High altitude Venus' upper haze from SOIR onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Takagi, Seiko; Mahieux, Arnaud; Wilquet, Valérie; Robert, Séverine; Drummond, Rachel; Carine Vandaele, Ann; Iwagami, Naomoto

    2015-04-01

    The Venus cloud consists of a main cloud deck at 47 - 70 km, with thinner hazes above and below. The upper haze on Venus lies above the main cloud surrounding the planet, ranging from the top of the cloud (70 km) up to as high as 90 km. The Solar Occultation in the InfraRed (SOIR) onboard Venus Express is designed to measure the atmospheric transmission at high altitudes (65 - 165 km) in the infrared (IR, 2.2 - 4.3 µm) with high spectral resolution by solar occultation. We investigated haze optical properties of Venus at above 90 km by analyzing SOIR spectral data. Vertical and latitudinal profiles of haze extinction, optical thickness, and mixing ratio were retrieved. These profiles exhibit the following characteristics. It shows that haze is present at altitude above 90 km although it has been recognized that the top of haze layer is 90 km. Extinctions vary order of magnitude every occultation. Extinctions are appeared to be independent of wavelength. This makes it clear that haze particles are sufficiently-small in size in comparison with observation wavelength. We find that haze extinction and optical thickness at low latitude are two times thicker than those at high latitude. One of the notable results is that mixing ratio of haze increases at above 90 km at both high and low latitudes. It's the first time that haze is speculated to be produced at high altitude. In this paper, haze transport and increase processes will be discussed to explain the results from SOIR observation.

  14. Venus Express set for launch to the cryptic planet

    NASA Astrophysics Data System (ADS)

    2005-10-01

    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

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

    NASA Astrophysics Data System (ADS)

    2005-11-01

    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

  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. 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 μm 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 μm-atm and ∼0.4-1.8 μm-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 μm-atm, 0.03-0.31 μm-atm and 0.01-0.13 μm-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 μm 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

  18. Study of the nightside Venus upper haze from VIRTIS-M / Venus Express limb observations

    NASA Astrophysics Data System (ADS)

    Gorinov, D.; Ignatiev, N.; Zasova, L.; Piccioni, G.; Drossart, P.

    2014-04-01

    This work studies the structure of the aerosol in the upper haze of Venus (75-95 km). According to several nightside limb observations made by VIRTIS (IR imaging spectrometer on-board the Venus Express spacecraft) a haze of particles can sometimes be seen on the planet's limb. These observations are also confirmed by the similar results, gained by SPICAV/SOIR, another experiment on the same mission, operating however in a different geometry. By using the model ARS [2], which simulates the radiative transfer in the venusian atmosphere, we were able to create the intensity profiles and to try to fit them (forward modeling) into the experimental data. As a result of these calculations, a lot of particle parameters were found out, including their size distribution, altitude distribution and number density.

  19. A Conceptual Venus Rover Mission Using Advanced Radioisotope Power Systems

    NASA Astrophysics Data System (ADS)

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

    2006-01-01

    This concept study demonstrates that a long lived Venus rover mission could be enabled by a novel application of advanced RPS technology. General Purpose Heat Source (GPHS) modules would be employed to drive an advanced thermoacoustic Stirling engine, pulse tube cooler and linear alternator that provides electric power and cooling for the rover. The Thermoacoustic Stirling Heat Engine (TASHE) is a system for converting high-temperature heat into acoustic power which then drives linear alternators and a pulse tube cooler to provide both electric power and coolin6g for the rover. A small design team examined this mission concept focusing on the feasibility of using the TASHE system in this hostile environment. A rover design is described that would provide a mobile platform for science measurements on the Venus surface for 60 days, with the potential of operating well beyond that. A suite of science instruments is described that collects 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 at under 50 °C.

  20. ESA to present the latest Venus Express results to the media

    NASA Astrophysics Data System (ADS)

    2007-11-01

    The launch of Venus Express back in November 2005 represented a major milestone in the exploration of Venus — a planet unvisited by any dedicated spacecraft since the early 1990s. One of the fundamental questions being addressed by the Venus Express mission is why a world so similar to Earth in mass and size has evolved so differently, to become the noxious and inhospitable planet it is today. Since it started its scientific observations in July 2006, Venus Express has been making the most detailed study of the planet’s thick and complex atmosphere to date. The latest findings not only highlight the features that make Venus unique in the solar system but also provide fresh clues as to how the planet is — despite everything — a more Earth-like planetary neighbour than one could have imagined. The results will appear in a special section of the 29 November issue of the journal Nature containing nine individual papers devoted to Venus Express science activities. Media organisations interested in attending the press conference are invited to register via the form attached below. Media that cannot attend will have the opportunity to follow the press conference via the following phone line: +33 1 58 99 57 42 (listening-mode only).The results presented at the press conference are embargoed until 28 November 19:00 CET. For more information ESA Media Relations Office Tel: +33 1 5369 7299 Fax: +33 1 5369 7690 Media event programme ‘Venus: a more Earth-like planetary neighbour’ Latest results from Venus Express 28 November 2007, 15:00, room 137 ESA Headquarters, 8-10 rue Mario-Nikis, Paris 15:00 Introduction, by Håkan Svedhem, ESA Venus Express Project Scientist 15:07 Venus: What we knew before, by Fred Taylor, Venus Express Interdisciplinary Scientist 15:15 Temperatures in the atmosphere of Venus, by Jean-Loup Bertaux, SPICAV Principal Investigator 15:25 The dynamic atmosphere of Venus, by Giuseppe Piccioni, VIRTIS Principal Investigator 15:40 Venus

  1. 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.

  2. Image processing and products for the Magellan mission to Venus

    NASA Technical Reports Server (NTRS)

    Clark, Jerry; Alexander, Doug; Andres, Paul; Lewicki, Scott; Mcauley, Myche

    1992-01-01

    The Magellan mission to Venus is providing planetary scientists with massive amounts of new data about the surface geology of Venus. Digital image processing is an integral part of the ground data system that provides data products to the investigators. The mosaicking of synthetic aperture radar (SAR) image data from the spacecraft is being performed at JPL's Multimission Image Processing Laboratory (MIPL). MIPL hosts and supports the Image Data Processing Subsystem (IDPS), which was developed in a VAXcluster environment of hardware and software that includes optical disk jukeboxes and the TAE-VICAR (Transportable Applications Executive-Video Image Communication and Retrieval) system. The IDPS is being used by processing analysts of the Image Data Processing Team to produce the Magellan image data products. Various aspects of the image processing procedure are discussed.

  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. 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

  5. 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.

  6. 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.

  7. 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.

  8. International Planetary Science Interoperability: The Venus Express Interface Prototype

    NASA Astrophysics Data System (ADS)

    Sanford Bussard, Stephen; Chanover, N.; Huber, L.; Trejo, I.; Hughes, J. S.; Kelly, S.; Guinness, E.; Heather, D.; Salgado, J.; Osuna, P.

    2009-09-01

    NASA's Planetary Data System (PDS) and ESA's Planetary Science Archive (PSA) have successfully demonstrated interoperability between planetary science data archives with the Venus Express (VEX) Interface prototype. Because VEX is an ESA mission, there is no memorandum of understanding to archive the data in the PDS. However, using a common communications protocol and common data standards, VEX mission science data ingested into the PSA can be accessed from a user interface at the Atmospheres Node of the PDS, making the science data accessible globally through two established planetary science data portals. The PSA makes scientific and engineering data from ESA's planetary missions accessible to the worldwide scientific community. The PSA consists of online services incorporating search, preview, download, notification and delivery basket functionality. Mission data included in the archive aside from VEX include data from the Giotto, Mars Express, Smart-1, Huygens, and Rosetta spacecraft and several ground-based cometary observations. All data are compatible to the Planetary Data System data standard. The PDS archives and distributes scientific data from NASA planetary missions, astronomical observations, and laboratory measurements. The PDS is sponsored by NASA's Science Mission Directorate. Its purpose is to ensure the long-term usability of NASA data and to stimulate advanced research. The architecture of the VEX prototype interface leverages components from both the PSA and PDS information system infrastructures, a user interface developed at the New Mexico State University, and the International Planetary Data Alliance (IPDA) Planetary Data Access Protocol (PDAP). The VEX Interoperability Project was a key project of the IPDA, whose objective is to ensure world-wide access to planetary data regardless of which agency collects and archives the data. A follow-on IPDA project will adapt the VEX Interoperability protocol for access in JAXA to the Venus Climate

  9. Investigation of air temperature on the nightside of Venus derived from VIRTIS-H on board Venus-Express

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Grassi, D.; Montabone, L.; Lebonnois, S.; Drossart, P.; Piccioni, G.

    2012-02-01

    We present the spatial distribution of air temperature on Venus' night side, as observed by the high spectral resolution channel of VIRTIS (Visible and Infrared Thermal Imaging Spectrometer), or VIRTIS-H, on board the ESA mission Venus Express. The present work extends the investigation of the average thermal fields in the northern hemisphere of Venus, by including the VIRTIS-H data. We show results in the pressure range of 100-4 mbar, which corresponds to the altitude range of 65-80 km. With these new retrievals, we are able to compare the thermal structure of the Venus' mesosphere in both hemispheres. The major thermal features reported in previous investigations, i.e. the cold collar at about 65-70°S latitude, 100 mbar pressure level, and the asymmetry between the evening and morning sides, are confirmed here. By comparing the temperatures retrieved by the VIRTIS spectrometer in the North and South we find that similarities exist between the two hemispheres. Solar thermal tides are clearly visible in the average temperature fields. To interpret the thermal tide signals (otherwise impossible without day site observations), we apply model simulations using the Venus global circulation model Venus GCM (Lebonnois, S., Hourdin, F., Forget, F., Eymet, V., Fournier, R. [2010b]. International Venus Conference, Aussois, 20-26 June 2010) of the Laboratoire de Météorologie Dynamique (LMD). We suggest that the signal detected at about 60-70° latitude and pressure of 100 mbar is a diurnal component, while those located at equatorial latitudes are semi-diurnal. Other tide-related features are clearly identified in the upper levels of the atmosphere.

  10. Power Conversion with a Stirling Cycle for Venus Surface Mission

    NASA Technical Reports Server (NTRS)

    Mellott, Ken

    2004-01-01

    The light-filtering characteristic of the dense, mostly-CO2 atmosphere of Venus, combined with the high atmospheric cloud cover, relegates the surface mission use of photovoltaic power systems and beckons for the independence and reliability of a nuclear-powered energy source. A multi-faceted Venus mission study was completed at NASA GRC in December of 2003 that resulted in the preliminary design of a helium- charged, kinematic Stirling converter, which is powered by nuclear, General Purpose Heat Source (GPHS) modules. The kinematic, Stirling power converter is configured to drive an electronics and sensor cooler in addition to a generator for electrical power. This paper briefly describes the design process and also describes and summarizes key features of the Stirling power converter preliminary design concept. With an estimated total efficiency of 23.4%, the power converter drives the electronics and sensor cooler, and also produces 100 watts of electricity. The converter rejects waste heat at a hot sink temperature of 500 C.

  11. 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,

  12. 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

  13. 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

  14. Atmospheric temperature in the Venus mesosphere, investigated by VIRTIS/Venus Express

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Grassi, D.; Piccioni, G.; Lebonnois, S.; Montabone, L.; Drossart, P.

    2012-04-01

    Atmospheric temperature, retrieved using remote sensing data acquired with the VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) instrument on board the European Venus Express mission, is presented for the night side of Venus both in the northern and southern hemispheres of the planet. The explored pressure range covers from 100 to 4 mbar, corresponding approximately to the altitude range from 65 to 80 km. Differences between the dusk and dawn sides are observed in the temperature values, the dawn being the coldest quadrant in the pressure range 100 to 12 mbar. The most important observed feature is the cold-collar region around 60-70°, which is 15 to 20 K colder than the temperature at the pole at 100 mbar (about 65 km), also showing a significant thermal inversion. A peculiar pattern of maxima and minima in temperature is observed at 100 and 12 mbar. The application of a global circulation model (Lebonnois et al., 2010) to our data allows to interpret the observed features as indication of diurnal and/or semidiurnal thermal tides (Migliorini et al., 2011).

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

    NASA Astrophysics Data System (ADS)

    2005-11-01

    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

  16. 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.

  17. 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

  18. 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.

  19. Progress towards a post-Venus Express Clouds & Haze reference model for Venus

    NASA Astrophysics Data System (ADS)

    Marcq, Emmanuel; Belyaev, Denis; Wilson, Colin; Wilquet, Valérie; Luginin, Mikhail

    2016-07-01

    With the end of Venus Express in 2014, the focus of the scientific community has gradually moved from the study of Venus Express mono-instrumental data sets to cross-instrumental studies involving pure modelization as well. This is especially true for the clouds and hazes that surround most of the planet between 48 and 70 km. They play a major role at the crossroads of various atmospheric processes among which the radiative budget as well as the dynamical and chemical coupling between the lower and upper atmosphere. In order to support such efforts, ISSI has supported from 2013 to 2015 a "Clouds & Hazes of Venus" scientific team involving Venus Express and ground-based observers as well as microphysical modelers. Together, they compared their results in order to achieve a more unified and consistent view of Venus' clouds and hazes, taking into account its spatial and temporal variability more in detail than previously available VIRA-1 and 2 cloud models. We will review the individual data sets and models that have been used, and then present our strategy towards a unified cloud model. We will first make available some observable parameters to the wider community through a web-based repository. Our future steps will involve more advanced techniques (data assimilation) in order to achieve our objective of a unified Venus clouds & haze model that encompasses its various variabilities as well as possible.

  20. 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.

  1. 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.

  2. Venus Express Measurement of ULF and ELF Signals in the Venus Ionosphere: Evidence for Extensive Electrical Activity in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Hart, R.; Russell, C. T.; Leinweber, H.; Zhang, T.

    2013-05-01

    Even though the surface of Venus is currently very dry, the atmosphere has extensive cloud cover. These clouds contain sulfuric acid particles that have properties sufficiently similar to water-ice that they would be expected to become charged, as in terrestrial clouds. Also the nitric oxide content of the Venus atmosphere, which is formed by lightning on Earth is similar to the terrestrial values. Thus it is not surprising that numerous manifestations of lightning on Venus have been reported. In this paper we use the Venus Express magnetic measurements to extend our understanding of Venus lightning. The gradiometer magnetometer configuration installed on Venus Express allows the cleaning of the data up to 6 KHz. We exploit these data in the second year of operation to add statistics to our existing data base. We show how ULF and ELF signals appear to reach the spacecraft via different paths but could have the same physical cause: electrical discharges in the Venus ionosphere.

  3. Dynamics of Venus' Southern hemisphere and South Polar Vortex from VIRTIS data obtained during the Venus Expres Mission

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    The VIRTIS instrument onboard Venus Express observes Venus in two channels (visible and infrared) obtaining spectra and multi-wavelength images of the planet. The images have been used to trace the motions of the atmosphere at different layers of clouds [1-3]. We review the VIRTIS cloud image data and wind results obtained by different groups [1-3] and we present new results concerning the morphology and evolution of the South Polar Vortex at the upper and lower cloud levels with data covering the first 900 days of the mission. We present wind measurements of the South hemisphere obtained by cloud tracking individual cloud features and higher-resolution wind results of the polar region covering the evolution of the South polar vortex. The later were obtained by an image correlation algorithm run under human supervision to validate the data. We present day-side data of the upper clouds obtained at 380 and 980 nm sensitive to altitudes of 66-70 km, night-side data in the near infrared at 1.74 microns of the lower cloud (45-50 km) and day and night-side data obtained in the thermal infrared (wavelengths of 3.8 and 5.1 microns) which covers the dynamical evolution of Venus South Polar vortex at the cloud tops (66-70 km). We explore the different dynamics associated to the varying morphology of the vortex, its dynamical structure at different altitudes, the variability of the global wind data of the southern hemisphere and the interrelation of the polar vortex dynamics with the wind dynamics at subpolar and mid-latitudes. Acknowledgements: Work funded by Spanish MICIIN AYA2009-10701 with FEDER support and Grupos Gobierno Vasco IT-464-07. References [1] A. Sánchez-Lavega et al., Geophys. Res. Lett. 35, L13204, (2008). [2] D. Luz et al., Science, 332, 577-580 (2011). [3] R. Hueso, et al., Icarus doi:10.1016/j.icarus.2011.04.020 (2011)

  4. Results of the Venus Express Aerobraking Campaign

    NASA Astrophysics Data System (ADS)

    Svedhem, Hakan; Müller-Wodarg, Ingo

    2014-11-01

    After a very successful mission orbiting Venus for more than 8 years, slowly the fuel is running out and the spacecraft will inevitably one day end up in the hot and acid atmosphere of the planet. Being near the end of the mission and in a position to accept some risk to the spacecraft we decided to take the opportunity to dip down deep into the atmosphere, 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 on board accelerometers gave direct measurements of the deceleration which in turn is directly proportional to the local atmospheric density. This provided an excellent way to study both the total density profile throughout the orbital arc in the atmosphere and small scale density variations in the region of the pericentre. The spacecraft behaved perfectly well throughout the whole campaign and provided a wealth of data both on the atmosphere and on the response of the spacecraft to the harsh environment with strong heat loads and some dynamic stress. At the time of the campaign the pericentre was 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.The so called "walk-in" phase started at an altitude of 190 km on 17 May and the campaign ended on 11 July, after having reached a lowest altitude of 129.2 km. Subsequently, a series of orbit control manoeuvres lifted up the pericentre to 460 km altitude and the science activities were resumed after a thorough check-out of the spacecraft. We have detected a highly variable atmosphere, both on a day to day basis and within the individual pericentre passes. The duration of each pass was approximately 100 s and the maximum dynamic pressure achieved was more than 0.75 N/m2, probably a record for a spacecraft that continued its operation afterwards. The

  5. Sulfuric acid vapor in the atmosphere of Venus as observed by the Venus Express Radio Science experiment VeRa

    NASA Astrophysics Data System (ADS)

    Oschlisniok, Janusz; Pätzold, Martin; Häusler, Bernd; Tellmann, Silvia; Bird, Mike; Andert, Tom

    2016-04-01

    The cloud deck within Venus' atmosphere, which covers the entire planet between approx. 50 and 70 km altitude, consists mostly of liquid and gaseous sulfuric acid. The gaseous part increases strongly just below the main clouds and builds an approx. 15 km thick haze layer of H2SO4. This region is responsible for a strong absorption of radio waves as seen in VeRa radio science observations. The amount of the absorption, which is used to derive the abundance of gaseous sulfuric acid, depends on the signal frequency. VeRa probed the atmosphere of Venus between 2006 and 2015 with radio signals at 13 cm (S-band) and 3.6 cm (X-band) wavelengths. We present H2SO4 profiles derived from S-band and X-band absorption during the first occultation season in 2006. The comparison of the H2SO4 profiles derived from both frequency bands provides a reliable picture of the H2SO4 abundance. Distinct differences in the S- and X-band profiles may give a clue to increased SO2 abundances. The derived VeRa results shall be compared with results provided by other experiments onboard Venus Express as well as with previous missions.

  6. First results from VIRTIS on Venus Express 2.Radiative transfer and atmospheric modelling

    NASA Astrophysics Data System (ADS)

    Drossart, P.; Piccioni, G.; Coradini, A.; Arnold, G.; Sémery, A.; Peter, G.; Cosi, M.; Pasqui, C.; Bézard, B.; Marinangeli, L.; Virtis Team

    The VIRTIS observations of Venus will provide information on various levels into the atmosphere The atmosphere above the cloud will be observed by Venus Express both on day and night side in solar reflection and thermal emission with different type of radiative transfer models adapted to the different atmospheric domains Limb observations are expected to give access to mesospheric CO 2 and CO emissions through fluorescence observations non-LTE modelling of CO 2 and CO bands will constrain the physical parameters of these layers Spectroscopy of the 4-5 micron range with VIRTIS-M and --H channels will give access to thermal structure retrieval and cloud structure at the 60-90 km altitude levels Finally the deeper atmospheric windows limited by CO 2 and H 2 O bands are accessible only in thermal emission on the night side The sounded levels at 2 3 1 7 mu m are limited respectively to 30-20 km altitude when at shorter wavelength 1 18 1 10 1 01 0 9 and 0 85 mu m the hot surface of Venus is seen through the scattering clouds Atmospheric modelling is therefore the key to decrypt the mysteries of Venus by ultimately removing atmospheric contributions to search for possible variations of surface emissivity Results on the different types of atmospheric contributions observed by VIRTIS will be shown if the Venus Express mission permits

  7. 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.

  8. 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…

  9. A study of an orbital radar mapping mission to Venus. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A preliminary design of a Venus radar mapping orbiter mission and spacecraft was developed. The important technological problems were identified and evaluated. The study was primarily concerned with trading off alternate ways of implementing the mission and examining the most attractive concepts in order to assess technology requirements. Compatible groupings of mission and spacecraft parameters were analyzed by examining the interaction of their functioning elements and assessing their overall cost effectiveness in performing the mission.

  10. Requirements and capabilities for planetary missions. Venus orbiter imaging radar 1983, volume 3

    NASA Technical Reports Server (NTRS)

    Kindt, D. H.; Ball, G. G.; Bird, T. H.

    1976-01-01

    Two spacecraft will be launched in mid-1983 and inserted into a circular polar orbit around Venus about 6 months later. Elliptical orbits are also under consideration. The objective of the mission is imagery of the planet, at about the 200-m resolution level, with continuous altimetry and topographical studies. Science investigations will determine surface characteristics of the planet, study the surface/atmosphere interactions, and determine Venus' mass distribution. A plausible vehicle is based on a Mariner Jupiter/Saturn derivative; others being considered include a Lunar Polar Orbiter derivative and a Pioneer Venus Orbiter derivative.

  11. Ballistic mode Mercury orbiter mission opportunity handbook extension. [interplanetary trajectories for Venus swingbys to Mercury

    NASA Technical Reports Server (NTRS)

    Hollenbeck, G. R.; Lewis, P. S.; Rockenbach, P. C.

    1974-01-01

    Interplanetary trajectory characteristics are presented, for Venus swingbys to Mercury, where multiple revolutions about the Sun are permitted. Additional consideration is given to the use of multiple Venus swingbys and/or to midcourse, near perilhelion, propulsive maneuvers to improve the performance of the mission as measured in terms of payload in Mercury orbit. Missions in 1980, 1983, 1985 and 1988 were analyzed with navigation results also developed. An exploratory investigation established the availability of low energy mission opportunities in 1991, 1994, 1996 and 1999.

  12. 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.

  13. VIRTIS on Venus Express: retrieval of real surface emissivity on global scales

    NASA Astrophysics Data System (ADS)

    Arnold, Gabriele E.; Kappel, David; Haus, Rainer; Telléz Pedroza, Laura; Piccioni, Giuseppe; Drossart, Pierre

    2015-09-01

    The extraction of surface emissivity data provides the data base for surface composition analyses and enables to evaluate Venus' geology. The Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) aboard ESA's Venus Express mission measured, inter alia, the nightside thermal emission of Venus in the near infrared atmospheric windows between 1.0 and 1.2 μm. These data can be used to determine information about surface properties on global scales. This requires a sophisticated approach to understand and consider the effects and interferences of different atmospheric and surface parameters influencing the retrieved values. In the present work, results of a new technique for retrieval of the 1.0 - 1.2 μm - surface emissivity are summarized. It includes a Multi-Window Retrieval Technique, a Multi-Spectrum Retrieval technique (MSR), and a detailed reliability analysis. The MWT bases on a detailed radiative transfer model making simultaneous use of information from different atmospheric windows of an individual spectrum. MSR regularizes the retrieval by incorporating available a priori mean values, standard deviations as well as spatial-temporal correlations of parameters to be retrieved. The capability of this method is shown for a selected surface target area. Implications for geologic investigations are discussed. Based on these results, the work draws conclusions for future Venus surface composition analyses on global scales using spectral remote sensing techniques. In that context, requirements for observational scenarios and instrumental performances are investigated, and recommendations are derived to optimize spectral measurements for Venus' surface studies.

  14. Measurements of minor species below the clouds of Venus using VIRTIS/Venus Express.

    NASA Astrophysics Data System (ADS)

    Marcq, Emmanuel; Drossart, Pierre; Bézard, Bruno; Piccioni, Giuseppe; Henry, Florence; Reess, Jean-Michel

    2016-07-01

    VIRTIS spectral imager was part of Venus Express (2006-2014) payload. On the night side, it was able to analyse the thermal radiation near 2.3 μm originating from the deep atmosphere of Venus and leaking through its optically thick cloud layers [Tsang et al., 2008; Marcq et al., 2008] measuring various minor species in the 30-40 km altitude range: CO, OCS, H_2O, HDO, SO_2, HF. Most of VIRTIS data acquired since 2008 have not been processed until now. Yet a more complete analysis of this data set would be very interesting, especially in the context of two recent discoveries brought by other Venus Express instruments (SPICAV and VMC): the confirmation of the large spatial and temporal variabiliy of SO_2 above Venus's clouds top [Marcq et al., 2013], indicative of a dynamical coupling between the lower atmosphere reservoir and the lower mesosphere; the unexpected correlation between the low latitude topography and several observable parameters at cloud top level [Fedorova et al., 2015; Bertaux et al., submitted]: zonal wind speed, UV albedo, H_2O abundance. We will present here preliminary results about these new composition measurements with an emphasis put on the search for various correlations (latitude/longitude, local solar time, date, etc.)

  15. 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 ~ 1μm 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 ~ 0.25μm, 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 τh is increasing with increasing latitude, in

  16. The search for active volcanism on Venus with Venus Express/VIRTIS data

    NASA Astrophysics Data System (ADS)

    Tsang, C. C. C.; Virtis Team

    The composition of the lower atmosphere of Venus is of primary importance in understanding the past and indeed current evolution of climatology on this most enigmatic of planets In discovering the near infrared windows centered at 2 3 1 7 and 1 18 microns Allen and Crawford 1 in 1983 paved the way for the lower 40km of the atmosphere to be probed remotely from space This has led Venus Express to carry imaging spectrometers such as VIRTIS to make full use of this phenomenon Some fundamental questions concerning the exact makeup of the atmosphere will be answered by analyzing VIRTIS data Data collected from past observations indicate the possibility of current volcanic activity on the surface of Venus The monitoring of SO 2 at the cloud tops indicate a steady drop in concentration suggesting a possible source of SO 2 is due to volcanism 2 whilst deep atmospheric values below the clouds suggest a uniform mixing ratio 3 The analysis VIRTIS data at 2 48 micron window will no doubt shed light on this matter Analysis of the micro-window complex at 1 18 microns shows that we can image the surface of the planet in the infrared whilst negating most of the effects of the atmosphere 4 We can monitor the surface brightness temperatures to look for hot spots indicative of volcanic plumes another key goal of Venus Express and VIRTIS We have developed a radiative transfer model to analyse Venus Express VIRTIS data in the near infrared windows The retrieval model uses the correlated-k distribution method which incorporates the use

  17. O+ pickup ions outside of Venus' bow shock: Venus Express observations

    NASA Astrophysics Data System (ADS)

    Wei, Yong; Fraenz, Markus; Dubinin, Eduard; Zhang, Tielong; Jarvinen, Riku; Wan, Weixing; Kallio, Esa; Collinson, Glyn; Barabash, Stars; Norbert, Krupp; Woch, Joachim; Lundin, Rickard; delva, Magda

    2013-04-01

    Pickup ions are ions of planetary origin that become assimilated into the solar wind flow through their interaction with the solar wind magnetic and electric field. The speed of pickup ions varies between zero and twice the underlying plasma flow component perpendicular to magnetic field vector. For the unmagnetized planet Venus and Mars, oxygen (O+) pickup ions are known to be important because they can modify the global configuration of planetary plasma environment and significantly contribute to the atmospheric O+ loss [1]. Since the kinetic energy of an O+ pickup ion can reach 64 times that of a co-moving proton, an instrument must be able to measure O+ ions with energy of at least tens of keV to investigate the O+ pickup ion distribution from planetary ionosphere to solar wind. The in-situ observations and simulations at Mars have shown that the energy of O+ pickup ions can be 55-72 keV outside of the bow shock [2]. For Venus case, the plasma analyzer (OPA) onboard Pioneer Venus Orbiter (PVO), which was designed for solar wind monitoring, has an 8 keV energy limit for O+ detection and the limited sampling and data rate [3]. Therefore, OPA can only measure the O+ pickup ions in the sheath flow or inside the induced magnetosphere where the speed of ambient plasma flow is significantly lower than that of the unshocked solar wind outside of the bow shock. In addition, Galileo also did not capture O+ outside bowshock during its 1-hour Venus flyby though its plasma instrument had ability to cover the energy band of O+ pickup ions [4]. The Ion Mass Analyzer (IMA), included in the Analyzer of Space Plasma and Energetic Atoms (ASPERA-4) package on board Venus Express (VEX), determines the composition, energy, and angular distribution of ions in the energy range ~10 eV/q to 30 keV/q. Note that an O+ ion moving at the typical solar wind speed 400 km/s has kinetic energy 13.4 keV. Therefore, IMA has ability to measure the O+ pickup ions outside of Venus' bow shock. We

  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. 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.

  20. First Results of Venus Express Spacecraft Observations with Wettzell

    NASA Technical Reports Server (NTRS)

    Calves, Guifre Molera; Wagner, Jan; Neidhardt, Alexander; Kronschnabl, Gerhard; Ayucar, Miguel Perez; Cimo, Giuseppe; Pogrebenko, Sergei

    2010-01-01

    The ESA Venus Express spacecraft was observed at X-band with the Wettzell radio telescope in October-December 2009 in the framework of an assessment study of the possible contribution of the European VLBI Network to the upcoming ESA deep space missions. A major goal of these observations was to develop and test the scheduling, data capture, transfer, processing, and analysis pipeline. Recorded data were transferred from Wettzell to Metsahovi for processing, and the processed data were sent from Mets ahovi to JIVE for analysis. A turnover time of 24 hours from observations to analysis results was achieved. The high dynamic range of the detections allowed us to achieve a milliHz level of spectral resolution accuracy and to extract the phase of the spacecraft signal carrier line. Several physical parameters can be determined from these observational results with more observational data collected. Among other important results, the measured phase fluctuations of the carrier line at different time scales can be used to determine the influence of the solar wind plasma density fluctuations on the accuracy of the astrometric VLBI observations.

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

    NASA Astrophysics Data System (ADS)

    Parkinson, C. D.; Bougher, S. W.; Schulte, R.; Gao, P.; Yung, Y. L.; Vandaele, A.; Wilquet, V.; Mahieux, A.; Tellmann, S.

    2013-12-01

    Observations by the SPICAV/SOIR instruments aboard the Venus Express (VEx) spacecraft have revealed that the upper haze (UH) of Venus, between 70 and 90 km, is variable on the order of days to weeks and that it is populated by two particle modes. Gao et al. (submitted, Icarus, 2013) posit that one mode is made up of cloud particles that have diffused upwards from the main sulfuric acid cloud deck below, while the other mode is generated in situ by nucleation of sulfuric acid droplets on meteoric dust. They also propose that the observed variability in the UH is caused in part by vertical transient winds. They test this hypothesis by simulating a column of the Venus atmosphere from 40 to 100 km above the surface using a model based upon the Community Aerosol and Radiation Model for Atmospheres (CARMA). In this work, we significantly extend the analysis using the new more detailed SOIR/VeRa VEx temperature profiles which better constrain the observed strong CO2 15-micron cooling emission and 4.3-μm near-IR heating in Venus' atmosphere (and consistent with Venus Thermospheric General Circulation Model (VTGCM) simulations of Brecht et al. (2011)). We discuss our new results in context of the recent VEx observations (Wilquet et al., Icarus 217, 2012) with an intercomparison with the PVO data. We will also discuss similarities and differences arising from the PVO and VEx epochs where they exist. Additionally we report on our efforts self-consistently applying the VTGCM to constrain the degree to which effects due to vertical transient wind simulations can establish variability timescales and number density profiles that match VEx observations.

  2. O+ pickup ions outside of Venus' bow shock: Venus Express observation

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Fraenz, M.; Dubinin, E.; Zhang, T. L.; Wan, W.; Barabash, S.; Woch, J.; Lundin, R.

    2012-09-01

    Pickup ions are ions of planetary origin that become assimilated into the solar wind flow through their interaction with the solar wind magnetic and electric field. The speed of pickup ions varies between zero and twice the underlying plasma flow component perpendicular to magnetic field vector. For the unmagnetized planet Venus and Mars, oxygen (O+) pickup ions are known to be important because they can modify the global configuration of planetary plasma environment and significantly contribute to the atmospheric O+ loss [1]. Since the kinetic energy of an O+ pickup ion can reach 64 times that of a co-moving proton, an instrument must be able to measure O+ ions with energy of at least tens of keV to investigate the O+ pickup ion distribution from planetary ionosphere to solar wind. The in-situ observations and simulations at Mars have shown that the energy of O+ pickup ions can be 55-72 keV outside of the bow shock [2]. For Venus case, the plasma analyzer (OPA) onboard Pioneer Venus Orbiter (PVO), which was designed for solar wind monitoring, has an 8 keV energy limit for O+ detection and the limited sampling and data rate [3]. Therefore, OPA can only measure the O+ pickup ions in the sheath flow or inside the induced magnetosphere where the speed of ambient plasma flow is significantly lower than that of the unshocked solar wind outside of the bow shock. The Ion Mass Analyzer (IMA), included in the Analyzer of Space Plasma and Energetic Atoms (ASPERA-4) package on board Venus Express (VEX), determines the composition, energy, and angular distribution of ions in the energy range ~10 eV/q to 30 keV/q. Note that an O+ ion moving at the typical solar wind speed 400 km/s has kinetic energy 13.4 keV. Therefore, IMA has ability to measure the O+ pickup ions outside of Venus' bow shock. We have examined the IMA data during the solar minimum period 2006-2010, and identified about ten cases with clear signature of O+ pickup ion. With these observations, we will determine

  3. 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

  4. Venus Express observations of magnetic field fluctuations in the magnetosheath

    NASA Astrophysics Data System (ADS)

    Du, J.; Wang, C.; Zhang, T. L.; Volwerk, M.; Delva, M.; Baumjohann, W.

    2008-12-01

    Magnetic field fluctuations within a planetary magnetosheath play an important role in the solar wind interaction with the planet, since they can reconfigure the plasma flow and the magnetic field and transfer energy from the bow shock to the lower boundary. Many studies have been presented on the fluctuations in the terrestrial magnetosheath; however, hardly any studies have so far been carried out for Venusian magnetosheath fluctuations, except for Luhmann et al. [1983] and Vörös et al. [2008] who performed some case studies on the magnetosheath fluctuations at Venus. It was shown that the fluctuations are probably convected from the vicinity of the quasi-parallel bow shock along the streamlines. Based on the Venus Express observations in 2006 and 2007, we investigate the spatial distributions of magnetic field fluctuations in the Venus magnetosheath statistically.

  5. 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

  6. 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 α = 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 μmversus 0.9 - 1.05 μm). 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 μm in the clouds and/or the haze above them in these mid-latitudes. Small submicron (Reff = 0.23 μm) particles are detected mostly in the morning.

  7. Assessment of Guided Aerocapture and Entry for Venus In Situ Missions Using Mechanically Deployed Aerodynamic Decelerator

    NASA Astrophysics Data System (ADS)

    Saikia, S. J.; Saranathan, H.; Longuski, J. M.; Grant, M. J.

    2014-05-01

    The option of a a guided mechanically deployed aerodynamic decelerator (ADEPT) for in situ missions to Venus is evaluated to reduce both the peak deceleration loads to under 10g and and peak heat fluxes to less than 120 W/cm2.

  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. The polar atmosphere of Venus: Radio occultation measurements with Venus Express and Magellan

    NASA Astrophysics Data System (ADS)

    Hinson, D. P.; Tellmann, S.; Paetzold, M.; Haeusler, B.; Bird, M. K.; Tyler, G. L.

    2012-12-01

    The ESA Venus Express (VEx) spacecraft has been conducting radio occultation experiments since 2006. The results reported to date are based on data recorded by 35-m antennas of the ESA Tracking Station Network (e.g., Tellmann et al., J. Geophys. Res., 114, E00B36, 2009). We have recently begun to derive complementary new results through analysis of high-quality "open-loop" data recorded by a 70-m antenna of the NASA Deep Space Network. This experiment sounded the polar atmosphere in both hemispheres at latitudes greater than 75 degrees. As in previous occultation measurements in this region, there is a deep convective layer at altitudes below about 60 km. The convective layer is capped by an abrupt transition to stable stratification, and the overlying free air is modulated by vertically propagating gravity waves. These new results will be compared with Magellan radio occultation measurements acquired at comparable latitudes in the early 1990s and with the VEx results reported by Tellmann et al. (2009). Our analysis also illustrates some of the challenges that can arise in radio occultation measurements at Venus. For example, the sharp temperature minimum at the tropopause creates a thin layer that eludes radio occultation sounding owing to its peculiar refractive properties. This research is funded in part by NASA Grant NNX10AE22G of the Venus Express Participating Scientist Program.

  10. Infrared spectrometry of Venus: IR Fourier spectrometer on Venera 15 as a precursor of PFS for Venus express

    NASA Astrophysics Data System (ADS)

    Zasova, L. V.; Moroz, V. I.; Formisano, V.; Ignatiev, N. I.; Khatuntsev, I. V.

    2004-01-01

    Thermal infrared spectrometry in the range 6-40 μm with spectral resolution of 4.5-6.5 cm -1 was realized onboard of Venera 15 for the middle atmosphere of Venus investigations. The 3-D temperature and zonal wind fields ( h, ϕ, LT) in the range 55-100 km and the 3-D aerosol field ( h, ϕ, LT) in the range 55-70 km were retrieved and analyzed. The solar related waves at isobaric levels, generated by the absorbed solar energy, were investigated. In the thermal IR spectral range the, ν1, ν2 and ν3 SO 2 and the H 2O rotational (40 μm) and vibro-rotational (6.3 μm) absorption bands are observed and used for minor compounds retrieval. An advantage of the thermal infrared spectrometry method is that both the temperature and aerosol profiles, which need for retrieval of the vertical profiles of minor compounds, are evaluated from the same spectrum. The Fourier spectrometer on Venera-15 may be considered as a precursor of the Planetary Fourier Spectrometer (PI Prof. V. Formisano), which is included in the payload of the planned Venus Express mission. It has a spectral range 0.9-45 μm, separated into two channels: a short wavelength channel (SWC) in the range 0.9-5 μm and a long wavelength channel (LWC) from 6 to 45 μm, and spectral resolution of 1-2 cm -1. In the history of planetary Fourier spectrometry the PFS is a unique instrument, which possesses a short wavelength channel. A functioning of this instrument on the polar orbit with a good spatial and local time coverage will advance our knowledge in the fundamental problems of the Venus atmosphere.

  11. Concept study for a Venus Lander Mission to Analyze Atmospheric and Surface Composition

    NASA Astrophysics Data System (ADS)

    Kumar, K.; Banks, M. E.; Benecchi, S. D.; Bradley, B. K.; Budney, C. J.; Clark, G. B.; Corbin, B. A.; James, P. B.; O'Brien, R. C.; Rivera-Valentin, E. G.; Saltman, A.; Schmerr, N. C.; Seubert, C. R.; Siles, J. V.; Stickle, A. M.; Stockton, A. M.; Taylor, C.; Zanetti, M.; JPL Team X

    2011-12-01

    We present a concept-level study of a New Frontiers class, Venus lander mission that was developed during Session 1 of NASA's 2011 Planetary Science Summer School, hosted by Team X at JPL. Venus is often termed Earth's sister planet, yet they have evolved in strikingly different ways. Venus' surface and atmosphere dynamics, and their complex interaction are poorly constrained. A lander mission to Venus would enable us to address a multitude of outstanding questions regarding the geological evolution of the Venusian atmosphere and crust. Our proposed mission concept, VenUs Lander for Composition ANalysis (VULCAN), is a two-component mission, consisting of a lander and a carrier spacecraft functioning as relay to transmit data to Earth. The total mission duration is 150 days, with primary science obtained during a 1-hour descent through the atmosphere and a 2-hour residence on the Venusian surface. In the atmosphere, the lander will provide new data on atmospheric evolution by measuring dominant and trace gas abundances, light stable isotopes, and noble gas isotopes with a neutral mass spectrometer. It will make important meteorological observations of mid-lower atmospheric dynamics with pressure and temperature sensors and obtain unprecedented, detailed imagery of surface geomorphology and properties with a descent Near-IR/VIS camera. A nepholometer will provide new constraints on the sizes of suspended particulate matter within the lower atmosphere. On the surface, the lander will quantitatively investigate the chemical and mineralogical evolution of the Venusian crust with a LIBS-Raman spectrometer. Planetary differentiation processes recorded in heavy elements will be evaluated using a gamma-ray spectrometer. The lander will also provide the first stereo images for evaluating the geomorphologic/volcanic evolution of the Venusian surface, as well as panoramic views of the sample site using multiple filters, and detailed images of unconsolidated material and rock

  12. The Rationale for a New High-resolution Imaging Radar Mission to Venus

    NASA Astrophysics Data System (ADS)

    Herrick, R. R.; Sharpton, V. L.; Gens, R.; Ghent, R. R.; Gilmore, M. S.; Grimm, R. E.; Johnson, C. L.; McGovern, P. J.; Meyer, F.; Mouginis-Mark, P. J.; Plaut, J. J.; Sandwell, D. T.; Simons, M.; Solomon, S. C.

    2009-12-01

    Magellan, NASA’s last geoscience mission to Venus, provided synthetic aperture radar (SAR) images at ~100-m resolution, topography at ~10-km resolution, and the gravity field at ~300-km resolution. Although that mission provided a major advance in our understanding of the planet, basic questions about the geologic history of Venus remain unresolved. For example, hypotheses on the planet’s surface evolution range from uniformitarian to catastrophic, and assessments of current geologic activity range from earth-comparable levels of volcanic and tectonic activity to a surface shaped only by occasional impact and eolian processes. It is now feasible to send a mission to Venus that could provide SAR imaging at 1-5-m resolution; topography with tens-of-meters spatial resolution by utilizing interferometric SAR (InSAR) and stereo radargrammetry; and surface deformation at centimeter-scale vertical resolution through InSAR. Such a mission would substantially further our understanding of Venus by means of: (1) assessing the fundamental framework of the planet's geologic history (e.g., catastrophic change, slow evolution, uniformitarian) by imaging key stratigraphic contacts; (2) expanding the global framework of geomorphic unit types and relative stratigraphy with reconnaissance surveys of large geographic provinces; (3) directly detecting volcanic and tectonic activity through imaging of flows and fault-related activities (e.g., landslides) that occur between imaging passes; (4) monitoring present-day volcanic and tectonic activity with repeat-pass InSAR deformation studies; (5) constraining the nature of Venusian geologic volcanic and tectonic processes, and their relationship to mantle convective processes; (6) understanding the role of eolian processes in modifying the surface and the use of eolian features as stratigraphic markers (e.g., parabolic features) through detailed examination; (7) constraining Venusian impact processes, particularly the role of the

  13. Spectral inventory of the SOIR spectra onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Robert, Séverine; Mahieux, Arnaud; Wilquet, Valérie; Drummond, Rachel; Carine Vandaele, Ann

    2013-04-01

    The set of spectra recorded by the SOIR instrument on board Venus Express have been carefully studied from a spectroscopic point of view. The SOIR instrument combines an echelle spectrometer and an Acousto-Optical Tunable Filter for order selection. It performs solar occultation measurements in the IR region (2.2 - 4.4 μm) at a resolution of 0.10 - 0.24 cm-1 [1]. The wavelength range probed by SOIR allows a detailed chemical inventory of the Venus atmosphere above the cloud layer (65 to 180 km) with emphasis on the vertical distribution of gases (CO2, CO, H2O, HCl, HF, ...). The sensitivity of the SOIR instrument and the high concentration of CO2 on Venus, coupled with the long absorption paths sounded during solar occultations, enable us to detect weak absorption bands of rare CO2 isotopologues [2, 3]. The spectra are analysed using ASIMAT, an in-house Matlab algorithm [4]. It is based on the Optimal Estimation Method [5] with the aim to deduce physical characteristics (densities, temperature) of the Venus atmosphere from the spectra recorded using SOIR. The spectra were fitted using HITRAN 2008 [6]. A tool of automatic assignment was developed and applied to each spectrum leading to the creation of the wavenumber list of each line visible in the SOIR spectra. The tools used to calibrate the spectra, to characterize the residuals and to produce the line list will be described extensively for a selected number of orbits. References 1. Nevejans, D., et al., Compact high-resolution space-borne echelle grating spectrometer with AOTF based on order sorting for the infrared domain from 2.2 to 4.3 micrometer. Applied Optics, 2006. 45(21): p. 5191-5206. 2. Wilquet, V., et al., Line parameters for the 01111-00001 band of 12C16O18O from SOIR measurements of the Venus atmosphere. J. Quant. Spectrosc. Radiat. Transfer, 2008. 109: p. 895-905. 3. Robert, S., et al., Assignment and rotational analysis of new absorption bands of carbon dioxide isotopologues in Venus spectra. J

  14. In-Situ Exploration of Venus: Major Science Objectives, Investigations, and Mission Platform Options

    NASA Astrophysics Data System (ADS)

    Baines, K. H.; Limaye, S. S.; Hall, J. L.; Atreya, S. K.; Bullock, M. A.; Crisp, D.; Grinspoon, D. H.; Mahaffy, P. R.; Russell, C. T.; Webster, C. R.; Zahnle, K. J.

    2013-12-01

    In-situ missions to Venus have been recommended by both the 2011 and 2003 Decadal Studies of the NRC and have been proposed numerous times to NASA's Discovery and New Frontiers programs as well as to ESA's Cosmic Vision program. Such missions would revolutionize our understanding of Venus, as they address key questions of Venus's origin, evolution, and current state via high precision measurements of (1) noble gases and their isotopes, and (2) reactive trace gases and aerosol associated with Venus's active photo- and thermo-chemistry and sulfur cycle, including components potentially responsible for the poorly-understood uv-absorbing haze layer. Fundamental questions, as promoted in recent VEXAG documents, include: (1) Did Venus, Mars, and Earth have a common origin? (2) What roles did comets from the outer Solar System play in delivering volatiles to Venus? (3) Did Venus once have and lose a global ocean? (4) How much has Venus outgassed, and what is the current rate of outgassing, particularly of sulfur, the major driver of Venus clouds? and (5) Through the deposition of energy within them, what role do these clouds play in (a) driving the cloud-level thermal structure and (b) generating and maintaining the super-rotating zonal windfield that covers the globe? Fundamental answers could be uniquely provided through in-situ sampling via mass spectrometry of the noble gases and their isotopes - in particular of the 8 stable Xe isotopes, the bulk abundances of Kr, and the 3 isotopes of Ne. Measurements of the relative abundances of the light isotopes of N, O, H, S and O, by, for example, tunable laser spectrometry, would provide additional insights into Venus's origin, surface outgassing and planetary escape. Such measurements could be performed by probes, landers, or balloons. On descent through the uv-absorbing layer and the surrounding H2SO4 cloud, each of these platforms could explore both the absorber and sulfur-cycle-associated reactive species and aerosols

  15. Future Exploration of Venus

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay

    Venus has been the target of exploration for half a century, before the successful Mariner 2 fly-by in December 1962. The decade after that was marked by growing sophistication in the instruments and spacecraft. During the second decade of Venus exploration (1972 - 1981) the instruments and spacecraft had advanced to make the first detailed survey of the planet and image the surface. During the third decade Venus was explored with more advanced instruments such as synthetic aperture radar and by balloons - the only balloons in another atmosphere ever flown till present. Then came a long pause until 2005 when ESA launched Venus Express, which is still orbiting the planet and returning data. The nearly two-dozen missions flown to Venus have painted a puzzling picture of Venus - we still do not have answers to some key questions. The foremost is why did Venus evolve so differently from Earth? International space agencies and scientists have been considering various approaches to exploring Venus through small and large missions. The Venus Exploration Analysis Group (NASA) has developed a Venus Exploration Roadmap and a comprehensive list of goals, objectives and investigations (www.lpi.usra.edu/vexag), but an international coordinated, comprehensive plan to explore Venus is needed. To fill this void, the COSPAR International Venus Exploration Working Group (IVEWG) has been active in fostering dialog and discussions among the space faring agencies. One small step in the future exploration of Venus is the formation of a joint Science Definition Team (SDT) (NASA and Roscosmos/IKI) for Russia’s Venera-D mission in early 2014. The team is expected to submit a report to respective agencies in early 2015. Towards identifying key surface regions and atmospheric regions of Venus, a workshop is being held in May 2014 by VEXAG to seek community input. It is likely that calls for proposals for missions will also be announced under the M class by ESA and under the Discovery

  16. The latest results on the energetic neutral atoms and plasma of Venus from the ASPERA-4 instrument of Venus Express

    NASA Astrophysics Data System (ADS)

    Barabash, S.; Sauvaud, J.-A.; Aspera-4

    The Venus Express mission carries the instrument ASPERA-4 Analyzer of Space Plasmas and Energetic Atom to perform for the first time comprehensive plasma measurements at Venus ASPERA-4 is a replica of the instrument ASPERA-3 for the Mars Express mission orbiting Mars for about 2 years The general scientific objective of the ASPERA-4 experiment is to study the solar wind - atmosphere interaction and characterize the plasma atmospheric escape through energetic neutral atom ENA imaging and in-situ ion and electron measurements The ASPERA-4 instrument comprises four sensors two ENA sensors and an electron and ion spectrometer The Neutral Particle Imager NPI provides measurements of the integral ENA flux in the energy range 0 1 - 60 keV with no mass and energy resolution but comparatively high angular resolution 4 6 deg x 11 5 deg The Neutral Particle Detector NPD provides measurements of the ENA flux in the energy range 0 1 - 10 keV resolving velocity and mass H and O with a coarse angular resolution The Electron Spectrometer ELS is a standard top-hat electrostatic analyzer in a very compact design with the high 8 energy resolution to perform photoelectron spectroscopy These three sensors are located on a scanning platform to cover ideally the full sphere Ion Mass Analyzer IMA provides ion measurements in the energy range 0 01 - 30 keV q for the main ion components 1 2 4 16 amu q and the group of molecular ions 20 - 80 amu q The instantaneous field of view is 4 6 deg x 360 deg Electrostatic sweeping performs the elevation 90 deg

  17. 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.

  18. 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.

  19. 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 μm, 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.

  20. Venus

    NASA Astrophysics Data System (ADS)

    Lanzerotti, Louis J.

    It was a scant few decades ago that Venus was commonly thought to be a companion planet to the earth, probably capable of supporting life in a rainy, carboniferous, swampy environment. While numerous speculations of the possible existence of various life forms were rife, the obscuration of the planet's surface by its cloud layers prevented more “detailed” interpretations of Venus such as those Lowell and others were able to make for Mars, where surface markings were easily distinguishable by telescope.Venus is now known to have as diverse a set of characteristics and to be as unique in its own right as any of the nine known planets in the solar system. Although scientists search for underlying principles by which to describe and ultimately to understand nature, it is abundantly clear now that each of the solar system planets, including Venus, has a significant number of unique characteristics which distinguish one from the other. Some of these characteristics may be only incidental to planetary evolution, but we are not absolutely confident as yet which are central to fundamental understanding and which can be ignored (is the unique existence of life on earth central or only incidental to this planet's evolution?).

  1. 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-μm window on Venus' night side. We used the infrared M-channel of the VIRTIS instrument, an imaging spectrometer for the range 1-5 μm with a resolution of about 17 nm. The 1.18-μm 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-μm 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.

  2. 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

  3. 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

  4. Low Altitude Large Scale Magnetic Fields in the Venus Ionosphere: Complementary Observations from the Pioneer Venus Orbiter and Venus Express

    NASA Astrophysics Data System (ADS)

    Villarreal, M. N.; Russell, C. T.; Luhmann, J. G.; Strangeway, R. J.; Zhang, T.

    2013-12-01

    The ionosphere of Venus has two end member states: magnetized and unmagnetized. When the solar wind dynamic pressure is low and the EUV flux high, the magnetic barrier forms at high altitudes where the plasma is collisionless. In this case the dayside ionosphere shows average weak fields punctuated by small-scale flux ropes and the nightside shows large scale nearly vertical fields associated with depletions or holes in the ionospheric density. When the dynamic pressure is high and the EUV flux is low, the magnetic field barrier is formed at lower altitudes where the ionosphere is collisional. Here the magnetic field enters the ionosphere to be carried downward by the subsolar circulation of the ionosphere. A strong magnetic belt builds up at low altitudes that wraps the planet and wraps around into the night ionosphere, shutting off the trans-terminator source of the nightside ionosphere to create the ';disappearing ionosphere' state with large scale horizontal nightside fields. Venus Express has observed this belt in the polar ionosphere and because of the characteristic spatial pattern of the field along the path of the satellite this belt was initially interpreted as giant flux ropes. These structures are better described as thin magnetic layers and not flux ropes. We re-analyze the VEX data from this perspective to better illustrate the properties of the observed polar field layers and their relationship to the draped magnetosheath fields.

  5. Venus In Situ Explorer Mission design using a mechanically deployed aerodynamic decelerator

    NASA Astrophysics Data System (ADS)

    Smith, B.; Venkatapathy, E.; Wercinski, P.; Yount, B.; Prabhu, D.; Gage, P.; Glaze, L.; Baker, C.

    The Venus In Situ Explorer (VISE) Mission addresses the highest priority science questions within the Venus community outlined in the National Research Council's Decadal Survey. The heritage Venus atmospheric entry system architecture, a 45° sphere-cone rigid aeroshell with a carbon phenolic thermal protection system, may no longer be the preferred entry system architecture compared to other viable alternatives being explored at NASA. A mechanically-deployed aerodynamic decelerator, known as the Adaptive Deployable Entry and Placement Technology (ADEPT), is an entry system alternative that can provide key operational benefits and risk reduction compared to a rigid aeroshell. This paper describes a mission feasibility study performed with the objectives of identifying potential adverse interactions with other mission elements and establishing requirements on decelerator performance. Feasibility is assessed through a launch-to-landing mission design study where the Venus Intrepid Tessera Lander (VITaL), a VISE science payload designed to inform the Decadal Survey results, is repackaged from a rigid aeroshell into the ADEPT decelerator. It is shown that ADEPT reduces the deceleration load on VITaL by an order of magnitude relative to a rigid aeroshell. The more benign entry environment opens up the VISE mission design environment for increased science return, reduced risk, and reduced cost. The ADEPT-VITAL mission concept of operations is presented and details of the entry vehicle structures and mechanisms are given. Finally, entry aerothermal analysis is presented that defines the operational requirements for a revolutionary structural-TPS material employed by ADEPT: three-dimensionally woven carbon cloth. Ongoing work to mitigate key risks identified in this feasibility study is presented.

  6. 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.

  7. First Results from VIRTIS on Venus Express1. From Surface to Cloud Level

    NASA Astrophysics Data System (ADS)

    Piccioni, Giuseppe; Drossart, P.; VIRTIS/Venus Express Team

    2006-09-01

    VIRTIS is the imaging spectrometer of the ESA/Venus Express mission, in orbit around Venus since 2006, April 11th. It consists in two channels : VIRTIS-M, an imaging spectrometer with 0.25 mrad instantaneous field of view, working from 0.3 to 1 μm at 2nm spectral sampling (VIRTIS-M-vis) and from 1 to 5.2 μm at 10 nm resolution (VIRTIS-M-ir) and VIRTIS-H, a high resolution spectrometer working from 1.9 to 5.0 μm on an aperture of 0.58 x 1.74 mrad at 2000 resolving power. The main scientific objectives for the lower part of the atmosphere are the following:

    • Surface characteristics
    • Composition of the lower atmosphere, and spatial or temporal variations (night side)
    • Cloud structure (composition, scattering properties, and dynamics)
    • Thermal structure
    An important new result from VIRTIS is the first detailed study of the South polar vortex. This feature exhibits unique characteristics of essential importance for the understanding of the global dynamics of Venus. The rotation of the vortex is observed by VIRTIS at different altitudes for different wavelengths. The vortex has a complex structure, exhibiting high thermal contrasts and filamentary clouds forming an inverse "S” shape. The 1.7 μm and 2.3 μm spectral images, observed in the night side within these deep atmospheric windows, are the first observations of the deep structure of the vortex. Future observations during the Venus Express mission will allow us to continue the vortex observation to study its long term variations.

  8. Mars Express and Venus Express Data Retention In-Flight Performance

    NASA Astrophysics Data System (ADS)

    Lebrédonchel, J.; Rombeck, F.-J.

    2007-08-01

    Venus, Mars and Earth, three out of the four inner or 'rocky' planets of the Solar System, have a lot in common: a solid surface you could walk on, a comparable surface composition, an atmosphere and a weather system. European Space Agency (ESA) Mars Express (MEx) and Venus Express (VEx) pioneer scientific missions aim at exploring these two neighbours of the Earth, in order to enrich our knowledge of our planet and of the Solar System. Both projects are based on the same spacecraft bus, and in particular on 'sister' Solid State Mass Memory (SSMM) units, in charge of the acquisition, storage and retrieval of all on board data, relevant both to the platform and to the instruments. This paper recalls the common SSMM design and the inner fault tolerant memory array module architecture based on Computer Off The Shelf (COTS) Samsung 64 Mbit Synchronous Dynamic Random Access Memory (SDRAM) chips, and presents the comparative in-flight data retention performance for both MEx and Vex units, since their respective June 2003 and November 2005 launches. Both units have shown to successfully withstand the radiative deep space environment, including during the outstanding October 2003 solar flare, and no uncorrectable data corruption was ever reported. Beyond this stable retention performance over time, the memory scrubbing correctable error accounting feedback allows evaluating the deep space Single Event Upset (SEU) rates, to be compared with the theoretical SSMM radiation assessment as well as with other previous missions in-flight qualitative reference performance records, and finally enables to derive a couple of recommendations from the lessons' learnt.

  9. Manned Mars lander launch-to-rendezvous analysis for a 1981 Venus-swingby mission

    NASA Technical Reports Server (NTRS)

    Faust, N. L.; Murtagh, T. B.

    1971-01-01

    A description is given of the return of a manned Mars lander by a launch from the surface of Mars to some intermediate orbit, with subsequent maneuvers to rendezvous with a primary spacecraft (called the orbiter) in a Mars parking orbit. The type of Mars mission used to demonstrate the analytical technique includes a Venus swingby on the Mars-to-Earth portion of the trajectory in order to reduce the total mission velocity requirement. The total velocity requirement for the mission considered (if inplane launches are assumed) is approximately 17,500 ft/sec.

  10. 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.

  11. 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.

  12. 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.

  13. Mars exploration, Venus swingby and conjunction class mission modes, time period 2000 to 2045

    NASA Technical Reports Server (NTRS)

    Young, A. C.; Mulqueen, J. A.; Skinner, J. E.

    1984-01-01

    Trajectory and mission requirement data are presented for Earth-Mars opposition class and conjunction class round trip stopover mission opportunities available during the time period year 2000 to year 2045. The opposition class mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg. The gravitational field of Venus was used to reduce the propulsion requirement associated with the opposition class mission. Representative space vehicle systems are sized to compare the initial mass required in low Earth orbit of one mission opportunity with another mission opportunity. The interplanetary space vehicle is made up of the spacecraft and the space vehicle acceleration system. The space vehicle acceleration system consists of three propulsion stages. The first propulsion stage performs the Earth escape maneuver; the second stage brakes the spacecraft and Earth braking stage into the Mars elliptical orbit and effects the escape maneuver from the Mars elliptical orbit. The third propulsion stage brakes the mission module into an elliptical orbit at Earth return. The interplanetary space vehicle was assumed to be assembled in and depart from the space station circular orbit.

  14. Understanding of the Venus upper atmosphere dynamics with O2(a1Δ) Venus Express observations

    NASA Astrophysics Data System (ADS)

    Soret, L.; Gérard, J.-C.; Piccioni, G.; Drossart, P.

    2012-04-01

    The O2(a1Δ) nightglow emission at 1.27 μm may be used as a tracer of the dynamics prevailing in the Venusian upper mesosphere. This emission has thus been observed with ground-based telescopes and from space with instruments such as VIRTIS on board Venus Express. Observations have shown that the emission maximum is statistically located close to the antisolar point at ~96 km. As originally suggested by Connes et al. (1979), such an emission results from the production of oxygen atoms on the Venus dayside by photodissociation and electron impact dissociation of CO2 and CO, which are then transported to the nightside by the subsolar to antisolar general circulation, where they recombine to create excited O2(a1Δ) molecules. Their radiative deexcitation produces the O2(a1Δ) nightglow with a maximum near the antisolar point. However, VIRTIS observations indicate that the O2(a1Δ) nightglow emission is highly variable, both in intensity and location. Actually, when considering individual observations, the patch of bright emission is rarely located at the antisolar point and the brighter area around this point is the result of statics accumulation. Also, when considering several individual observations acquired in a short period of time, it is possible to follow an individual emission patch and to deduce its displacement and its brightness variation due to activation or deactivation. In this study, we analyze several sequences of VIRTIS observations in order to understand the Venus upper mesosphere dynamics. We show that the intensity can vary by several megaRayleighs in a couple of hours with effective lifetimes on the order of several hours. The horizontal motion of the spots leads to the conclusion that winds in the 95-100 km region are in the range of 25 to 150 m s-1, in good agreement with the study by Hueso et al. (2008).

  15. 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

  16. Comparison of Thermal Structure Results from Venus Express and Ground Based Observations since Vira

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay

    2016-07-01

    An international team was formed in 2013 through the International Space Studies Institute (Bern, Switzerland) to compare recent results of the Venus atmospheric thermal structure from spacecraft and ground based observations made since the Venus International Reference Atmosphere (VIRA) was developed (Kliore et al., 1985, Keating et al., 1985). Five experiments on European Space Agency's Venus Express orbiter mission have yielded results on the atmospheric structure during is operational life (April 2006 - November 2014). Three of these were from occultation methods: at near infrared wavelengths from solar occultations, (SOIR, 70 - 170 km), at ultraviolet wavelengths from stellar occultations (SPICAV, 90-140 km), and occultation of the VEx-Earth radio signal (VeRa, 40-90 km). In-situ drag measurements from three different techniques (accelerometry, torque, and radio tracking, 130 - 200 km) were also obtained using the spacecraft itself while passive infrared remote sensing was used by the VIRTIS experiment (70 - 120 km). The only new data in the -40-70 km altitude range are from radio occultation, as no new profiles of the deep atmosphere have been obtained since the VeGa 2 lander measurements in 1985 (not included in VIRA). Some selected ground based results available to the team were also considered by team in the inter comparisons. The temperature structure in the lower thermosphere from disk resolved ground based observations (except for one ground based investigation), is generally consistent with the Venus Express results. These experiments sampled at different periods, at different locations and at different local times and have different vertical and horizontal resolution and coverage. The data were therefore binned in latitude and local time bins and compared, ignoring temporal variations over the life time of the Venus Express mission and assumed north-south symmetry. Alternating warm and cooler layers are present in the 120-160 altitude range in results

  17. VERITAS: A Mission Concept for the High Resolution Topographic Mapping and Imaging of Venus

    NASA Astrophysics Data System (ADS)

    Hensley, S.; Smrekar, S. E.; Pollard, B.

    2012-12-01

    Magellan, a NASA mission to Venus in the early 1990's, mapped nearly the entire surface of Venus with an S-band (12 cm) synthetic aperture radar and microwave radiometer and made radar altimeter measurements of the topography. These measurements revolutionized our understanding of the geomorphology, geology and geophysical processes that have shaped the evolution of the surface of Venus. The Magellan spacecraft had an elliptical orbit with an apoapsis of approximately 8000 km and a periapsis of 257 km and an orbital inclination of 86°. In this way the radar was able to collect long strips of data approximately 10000 km in length running north to south with altitudes varying from 3000 km to 257 km. During the remainder of the orbit the collected data was down linked to earth. The SAR mode operated in burst mode fashion whereby it transmitted a small string of pulses up to a couple of hundred pulses in length followed by a quiescent period when the radar ceased transmission and allowed interleaved operation of the altimeter and radiometer modes. This mode of operation allowed for a significant reduction in downlinked SAR imaging data at the expense of azimuth (i.e. along-track) resolution. However, the lack of finer resolution imagery and topography of the surface than that obtained by the Magellan mission has hampered the definitive answer to key questions concerning the processes and evolution of the surface of Venus. The Venus Emissivity, Radio Science, InSAR Topography And Spectroscopy (VERITAS) Mission is a proposed mission to Venus designed to obtain high resolution imagery and topography of the surface using an X-band radar configured as a single pass radar interferometer coupled with a multispectral NIR emissivity mapping capability. VERITAS would map surface topography with a spatial resolution of 250 m and 5 m vertical accuracy and generate radar imagery with 30 m spatial resolution. These capabilities represent an order of magnitude or better improvement

  18. 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 ( 1Δ) 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.

  19. Venus Express bistatic radar: High-elevation anomalous reflectivity

    NASA Astrophysics Data System (ADS)

    Simpson, Richard A.; Tyler, G. Leonard; Häusler, Bernd; Mattei, Riccardo; Pätzold, Martin

    2009-06-01

    Magellan (MGN) bistatic radar observations in 1994 confirmed earlier Pioneer Venus reports of unusual Venus surface reflectivity and emissivity at elevations above 6054 km radius. They also revealed that the anomalous values of surface dielectric constant $\\varepsilon$ near Cleopatra Patera included a large imaginary component ($\\varepsilon$ ≈ -i 100) at 13 cm wavelength, consistent with a semiconducting surface material. The MGN observations were conducted using a linearly polarized wave, canted at 45° with respect to the plane of incidence and radiated by the MGN synthetic aperture radar antenna toward the specularly reflecting region of the mean planetary surface. In 2006 similar experiments were conducted using 13 cm circularly polarized transmissions from Venus Express (VEX). The VEX signal-to-noise ratio (SNR) was lower than that of MGN, but elevated ∣$\\varepsilon$∣ has been inferred broadly over Maxwell Montes. A quasi-specular echo was detected near Cleopatra but with insufficient SNR to address the question of conductivity. An early failure of the VEX 13 cm radio system precludes further measurements with VEX.

  20. Using SFOC to fly the Magellan Venus mapping mission

    NASA Technical Reports Server (NTRS)

    Bucher, Allen W.; Leonard, Robert E., Jr.; Short, Owen G.

    1993-01-01

    Traditionally, spacecraft flight operations at the Jet Propulsion Laboratory (JPL) have been performed by teams of spacecraft experts utilizing ground software designed specifically for the current mission. The Jet Propulsion Laboratory set out to reduce the cost of spacecraft mission operations by designing ground data processing software that could be used by multiple spacecraft missions, either sequentially or concurrently. The Space Flight Operations Center (SFOC) System was developed to provide the ground data system capabilities needed to monitor several spacecraft simultaneously and provide enough flexibility to meet the specific needs of individual projects. The Magellan Spacecraft Team utilizes the SFOC hardware and software designed for engineering telemetry analysis, both real-time and non-real-time. The flexibility of the SFOC System has allowed the spacecraft team to integrate their own tools with SFOC tools to perform the tasks required to operate a spacecraft mission. This paper describes how the Magellan Spacecraft Team is utilizing the SFOC System in conjunction with their own software tools to perform the required tasks of spacecraft event monitoring as well as engineering data analysis and trending.

  1. Interplanetary Coronal Mass Ejections Observed by MESSENGER and Venus Express

    NASA Astrophysics Data System (ADS)

    Good, S. W.; Forsyth, R. J.

    2016-01-01

    Interplanetary coronal mass ejections (ICMEs) observed by the MESSENGER and Venus Express 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 MESSENGER data (primarily from March 2007 to April 2012), and 84 ICMEs in the surveyed Venus Express 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 MESSENGER, Venus Express, STEREO-A, STEREO-B and ACE were examined for multipoint signatures of the catalogued ICMEs. For spacecraft separations below 15° in heliocentric longitude, the second spacecraft observed the ICME flux rope in 82 % of cases; this percentage dropped to 49 % for separations between 15 and 30°, to 18 % for separations between 30 and 45°, and to 12 % for separations between 45 and 60°. As the spacecraft separation increased, it became increasingly likely that only the sheath and not the flux rope of the ICME was observed, in agreement with the notion that ICME flux ropes are smaller in longitudinal extent than the shocks or discontinuities that they often drive. Furthermore, this study has identified 23 ICMEs observed by pairs of spacecraft close to radial alignment. A detailed analysis of these events could lead to a better understanding of how ICMEs evolve during propagation.

  2. The OH Venus nightglow spectrum: Intensity and vibrational composition from VIRTIS—Venus Express observations

    NASA Astrophysics Data System (ADS)

    Soret, Lauriane; Gérard, Jean-Claude; Piccioni, Giuseppe; Drossart, Pierre

    2012-12-01

    Limb spectra of the OH nightglow emission corresponding to the Δv=1 and Δv=2 sequences have been collected with the VIRTIS infrared imaging spectrograph on board Venus Express between April 2006 and October 2008. A detailed statistical analysis shows that the peak intensity and altitude of the two vibrational sequences are significantly correlated, with a mean intensity ratio of the two sequences of 0.38±0.37. The altitude of the maximum of the Δv=2 emission is located ∼1 km lower than Δv=1. A spectral analysis shows that the Δv=1 sequence is composed at 44.6% by the (1-0) band, 9.3% by the (3-2) band and 7.1% by the (4-3) band. The Δv=2 emission is best fitted if solely including the (2-0) band. A non-LTE model of OH vibrational population by the O3+H reaction including radiative and collisional relaxation has been used to compare the expected spectral distribution, the altitude of the emission peak and the emission rate under different assumptions on the quenching processes to those observed with VIRTIS. The adopted carbon dioxide, atomic oxygen and ozone densities are based on recent Venus Express remote sensing measurements. We find that the “Sudden Death” quenching scheme by CO2 produces inadequate spectral distribution between the various bands and insufficient airglow brightness. Instead, the observed spectral distribution and the total emission intensity are reasonably well reproduced with the Single Quantum jump model, an O density profile peaking at 103.5 km with a maximum value of 1.9×1011 cm-3, a O3 density profile peaking at 5.8×106 cm-3 at 96.5 km and a H density profile close to 108 cm-3 between 90 and 120 km, in agreement with several photochemical models.

  3. 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

  4. 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.

  5. 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.

  6. Nuclear Polar VALOR: An ASRG-Enabled Venus Balloon Mission Concept

    NASA Astrophysics Data System (ADS)

    Balint, T. S.; Baines, K. H.

    2008-12-01

    In situ exploration of Venus is expected to answer high priority science questions about the planet's origin, evolution, chemistry, and dynamics as identified in the NRC Decadal Survey and in the VEXAG White Paper. Furthermore, exploration of the polar regions of Venus is key to understanding its climate and global circulation, as well as providing insight into the circulation, chemistry, and climatological processes on Earth. In this paper we discuss our proposed Nuclear Polar VALOR mission, which would target one of the polar regions of Venus, while building on design heritage from the Discovery class VALOR concept, proposed in 2004 and 2006. Riding the strong zonal winds at 55 km altitude and drifting poleward from mid-latitude this balloon-borne aerial science station (aerostat) would circumnavigate the planet multiple times over its one- month operation, extensively investigating polar dynamics, meteorology, and chemistry. Rising and descending over 1 km altitude in planetary waves - similar to the two VEGA balloons in 1985 - onboard instrumentation would accurately and constantly sample and measure other meteorological and chemical parameters, such as atmospheric temperature and pressure, cloud particle sizes and their local column abundances, the vertical wind component, and the chemical composition of cloud-forming trace gases. As well, when viewed with terrestrial radio telescopes on the Earth-facing side of Venus, both zonal and meridional winds would be measured to high accuracy (better than 10 cm/sec averaged over an hour). Due to three factors: the lack of sunlight near the poles; severe limitations on the floating mass-fraction available for a power source; and the science requirements for intensive and continuous measurements of the balloon's environment and movement, a long-duration polar balloon mission would require a long-lived internal power source in a relatively lightweight package. For our concept we assumed an Advanced Stirling Radioisotope

  7. 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.

  8. A Search for Viable Venus and Jupiter Sample Return Mission Trajectories for the Next Decade

    NASA Technical Reports Server (NTRS)

    Leong, Jason N.; Papadopoulos, Periklis

    2005-01-01

    Planetary exploration using unmanned spacecraft capable of returning geologic or atmospheric samples have been discussed as a means of gathering scientific data for several years. Both NASA and ESA performed initial studies for Sample Return Missions (SRMs) in the late 1990 s, but most suggested a launch before the year 2010. The GENESIS and STARDUST spacecraft are the only current examples of the SRM concept with the Mars SRM expected around 2015. A feasibility study looking at SRM trajectories to Venus and Jupiter, for a spacecraft departing the Earth between the years 2011 through 2020 was conducted for a university project. The objective of the study was to evaluate SRMs to planets other than Mars, which has already gained significant attention in the scientific community. This paper is a synopsis of the study s mission trajectory concept and the conclusions to the viability of such a mission with today s technology.

  9. 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.

  10. 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.

  11. 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.

  12. Future of Venus Research and Exploration

    NASA Astrophysics Data System (ADS)

    Glaze, L.; Limaye, S.; Nakamura, M.; Wilson, C.; Zasova, L.

    2014-04-01

    A great deal is known about Venus from the Venera, Pioneer-Venus, Magellan, and Venus Express missions. However, many significant questions remain regarding the origin, evolution and current geologic and atmospheric processes. Much can be learned from theoretical modeling of the planetary interior and atmospheric circulation, as well as from laboratory spectroscopic studies. However, to answer many of the outstanding questions, new space flight missions are needed. Multiple international space agencies are considering Venus as a possible destination for future exploration. Collaborative international participation provides a viable path to further understanding of Earth's sister planet and her role in the formation of our solar system.

  13. First observation of 628 CO 2 isotopologue band at 3.3 μm in the atmosphere of Venus by solar occultation from Venus Express

    NASA Astrophysics Data System (ADS)

    Bertaux, Jean-Loup; Vandaele, Ann Carine; Wilquet, Valérie; Montmessin, F.; Dahoo, R.; Villard, E.; Korablev, O.; Fedorova, A.

    2008-05-01

    The new ESA Venus Express orbiter is the first mission applying the probing technique of solar and stellar occultation to the atmosphere of Venus, with the SPICAV/SOIR instrument. SOIR is a new type of spectrometer used for solar occultations in the range 2.2-4.3 μm. Thanks to a high spectral resolving power R˜15,000-20,000 (unprecedented in planetary space exploration), a new gaseous absorption band was soon detected in the atmospheric transmission spectra around 2982 cm -1, showing a structure resembling an unresolved Q branch and a number of isolated lines with a regular wave number pattern. This absorption could not be matched to any species contained in HITRAN or GEISA databases, but was found very similar to an absorption pattern observed by a US team in the spectrum of solar light reflected by the ground of Mars [Villanueva, G.L., Mumma, M.J., Novak, R.E., Hewagama, T., 2008. Icarus 195 (1), 34-44]. This team then suggested to us that the absorption was due to an uncatalogued transition of the 16O 12C 18O molecule. The possible existence of this band was soon confirmed from theoretical considerations by Perevalov and Tashkun. Some SOIR observations of the atmospheric transmission are presented around 2982 cm -1, and rough calculations of line strengths of the Q branch are produced, based on the isotopic ratio measured earlier in the lower atmosphere of Venus. This discovery emphasizes the role of isotopologues of CO 2 (as well as H 2O and HDO) as important greenhouse gases in the atmosphere of Venus.

  14. 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).

  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 μm, 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. 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 μm 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

  17. 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.

  18. Fluctuations in the Venusian Ionosphere and Their Effect on Venus Express Lightning Detection Rates

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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 near periapsis. This is the expected frequency range for lightning-generated whistler-mode waves at Venus, between the local electron (~100 Hz) and ion gyrofrequencies (~1 Hz). These waves are right-hand circularly polarized and are guided by the local magnetic field. When the Venusian ionopause is low enough 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 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. In addition, the detection rate of whistler-mode signals varied with the solar cycle. 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.

  19. Exploring Venus: the Venus Exploration Analysis Group (VEXAG)

    NASA Astrophysics Data System (ADS)

    Ocampo, A.; Atreya, S.; Thompson, T.; Luhmann, J.; Mackwell, S.; Baines, K.; Cutts, J.; Robinson, J.; Saunders, S.

    In July 2005 NASA s Planetary Division established the Venus Exploration Analysis Group VEXAG http www lpi usra edu vexag in order to engage the scientific community at large in identifying scientific priorities and strategies for the exploration of Venus VEXAG is a community-based forum open to all interested in the exploration of Venus VEXAG was designed to provide scientific input and technology development plans for planning and prioritizing the study of Venus over the next several decades including a Venus surface sample return VEXAG regularly evaluates NASA s Venus exploration goals scientific objectives investigations and critical measurement requirements including the recommendations in the National Research Council Decadal Survey and NASA s Solar System Exploration Strategic Roadmap VEXAG will take into consideration the latest scientific results from ESA s Venus Express mission and the MESSENGER flybys as well as the results anticipated from JAXA s Venus Climate Orbiter together with science community inputs from venues such as the February 13-16 2006 AGU Chapman Conference to identify the scientific priorities and strategies for future NASA Venus exploration VEXAG is composed of two co-chairs Sushil Atreya University of Michigan Ann Arbor and Janet Luhmann University of California Berkeley VEXAG has formed three focus groups in the areas of 1 Planetary Formation and Evolution Surface and Interior Volcanism Geodynamics etc Focus Group Lead Steve Mackwell LPI 2 Atmospheric Evolution Dynamics Meteorology

  20. The first results from the ASPERA-4 instrument of Venus Express

    NASA Astrophysics Data System (ADS)

    Barabash, S.; Sauvaud, J.-A.; Fedorov, A.; Aspera-4

    The Venus Express mission carries the instrument ASPERA-4 Analyzer of Space Plasmas and Energetic Atom to perform for the first time comprehensive plasma measurements at Venus ASPERA-4 is a replica of the instrument ASPERA-3 for the Mars Express mission orbiting Mars for about 2 years The general scientific objective of the ASPERA-4 experiment is to study the solar wind - atmosphere interaction and characterize the plasma atmospheric escape through energetic neutral atom ENA imaging and in-situ ion and electron measurements The ASPERA-4 instrument comprises four sensors two ENA sensors and an electron and ion spectrometer The Neutral Particle Imager NPI provides measurements of the integral ENA flux in the energy range 0 1 - 60 keV with no mass and energy resolution but comparatively high angular resolution 4 6 deg x 11 5 deg The Neutral Particle Detector NPD provides measurements of the ENA flux in the energy range 0 1 - 10 keV resolving velocity and mass H and O with a coarse angular resolution The Electron Spectrometer ELS is a standard top-hat electrostatic analyzer in a very compact design with the high 8 energy resolution to perform photoelectron spectroscopy These three sensors are located on a scanning platform to cover ideally the full sphere Ion Mass Analyzer IMA provides ion measurements in the energy range 0 01 - 30 keV q for the main ion components 1 2 4 16 amu q and the group of molecular ions 20 - 80 amu q The instantaneous field of view is 4 6 deg x 360 deg Electrostatic sweeping performs the elevation 90 deg

  1. 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

  2. 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.

  3. 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.

  4. 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.

  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-σ 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

  8. Geologic interpretation of the near-infrared images of the surface taken by the Venus Monitoring Camera, Venus Express

    NASA Astrophysics Data System (ADS)

    Basilevsky, A. T.; Shalygin, E. V.; Titov, D. V.; Markiewicz, W. J.; Scholten, F.; Roatsch, Th.; Kreslavsky, M. A.; Moroz, L. V.; Ignatiev, N. I.; Fiethe, B.; Osterloh, B.; Michalik, H.

    2012-02-01

    We analyze night-time near-infrared (NIR) thermal emission images of the Venus surface obtained with the 1-μm channel of the Venus Monitoring Camera onboard Venus Express. Comparison with the results of the Magellan radar survey and the model NIR images of the Beta-Phoebe region show that the night-time VMC images provide reliable information on spatial variations of the NIR surface emission. In this paper we consider if tessera terrain has the different NIR emissivity (and thus mineralogic composition) in comparison to the surrounding basaltic plains. This is done through the study of an area SW of Beta Regio where there is a massif of tessera terrain, Chimon-mana Tessera, surrounded by supposedly basaltic plains. Our analysis showed that 1-μm emissivity of tessera surface material is by 15-35% lower than that of relatively fresh supposedly basaltic lavas of plains and volcanic edifices. This is consistent with hypothesis that the tessera material is not basaltic, maybe felsic, that is in agreement with the results of analyses of VEX VIRTIS and Galileo NIMS data. If the felsic nature of venusian tesserae will be confirmed in further studies this may have important implications on geochemical environments in early history of Venus. We have found that the surface materials of plains in the study area are very variegated in their 1-μm emissivity, which probably reflects variability of degree of their chemical weathering. We have also found a possible decrease of the calculated emissivity at the top of Tuulikki Mons volcano which, if real, may be due to different (more felsic?) composition of volcanic products on the volcano summit.

  9. 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-μm 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 μm, and at R 250 with the infrared M-channel, an imaging spectrometer for the range 1-5 μm. 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.

  10. High energy particles at Mars and Venus: Phobos-2, Mars Express and Venus Express observations and their interpretation by hybrid model simulations

    NASA Astrophysics Data System (ADS)

    McKenna-Lawlor, Susan; Kallio, Esa; Fram, Rudy A.; Alho, Markku; Jarvinen, Riku; Dyadechkin, Sergey; Wedlund, Cyril Simon; Zhang, Tielong; Collinson, Glyn A.; Futaana, Yoshifumi

    2013-04-01

    Mars and Venus can both be reached by Solar Energetic Particles (SEPs). Such high energy particles (protons, multiply charged heavy ions, electrons) penetrate the upper atmospheres of Mars and Venus because, in contrast to Earth, these bodies do not have a significant, global, intrinsic magnetic field to exclude them. One especially well documented, complex and prolonged SEP took in place in early 1989 (Solar Cycle 23) when the Phobos-2 spacecraft was orbiting Mars. This spacecraft had a dedicated high energy particle instrument onboard (SLED), which measured particles with energies in the keV range up to a few tens of MeV. There was in addition a magnetometer as well as solar wind plasma detectors onboard which together provided complementary data to support contemporaneous studies of the background SEP environment. Currently, while the Sun is displaying maximum activity (Solar Cycle 24), Mars and Venus are being individually monitored by instrumentation flown onboard the Mars Express (MEX) and Venus Express (VEX) spacecraft. Neither of these spacecraft carry a high energy particle instrument but their Analyzer of Space Plasmas and Energetic Atoms (ASPERA) experiments (ASPERA-3 on MEX and ASPERA-4 on VEX), can be used to study SEPs integrated over E ≥ ~30 MeV which penetrate the instrument hardware and form background counts in the plasma data. In the present work we present SEP events measured at Mars and Venus based on Phobos-2, 1989 data and on, more recent, MEX and VEX (identified from particle background) observations. We further introduce numerical global SEP simulations of the measured events based on 3-D self-consistent hybrid models (HYB-Mars and HYB-Venus). Through comparing the in situ SEP observations with these simulations, new insights are provided into the properties of the measured SEPs as well as into how their individual planetary bow shocks and magnetospheres affect the characteristics of their ambient Martian and Venusian SEP environments.

  11. 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

  12. 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.

  13. 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

  14. Exploring the surface of Venus

    NASA Astrophysics Data System (ADS)

    Helbert, J.; Mueller, N. T.; Smrekar, S. E.; Piccioni, G.; Drossart, P.

    2009-12-01

    The VIRTIS instrument on the ESA mission Venus Express has produced the first in-orbit mapping of the surface of Venus using the atmospheric windows near 1 micron. Based on the data returned by VIRTIS a map of surface brightness variations could be obtained which are indicative of emissivity variations on the surface. The mapping in general indiactes three surface types, characterized by average, increased and decreased emissivity. These surface types show a good correlation with geological units identified by radar mapping. In general high emissivity units are found on very fresh lava flows, while tesserae terrain is typically associated with the low emissivity unit. This completely new dataset, that is highly complementary to the geological mapping based on radar data can provide significant support for the design and planning of future missions to Venus. For the first time there are strong indications for the heterogeneity of the surface composition of Venus. This is not only important for the selection of potential landing sites, but can provide important insights in the evolution of Venus. To support the mapping activity and the instrument development for future Venus missions we have started to obtain high temperature emissivity spectra of analog materials at Venus surface temperatures. This laboratory measurements will provide for the first time realistic near infrared spectral data for the surface of Venus. Obtaining data of samples at 500°C and taking emissivity measurements at 1 micron is a very challenging task. After more than 3 years of preparation the setup at the Planetary Emissivity Laboratory in Berlin is near completion and first test measurements have been obtained successfully.

  15. 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.

  16. A new view of Earth's sister: Insights following nine years of Venus Express observations

    NASA Astrophysics Data System (ADS)

    Titov, Dmitrij; Svedhem, Håkan; Drossart, Pierre; Taylor, Fredric W.; Zhang, Tielong; Barabash, Stas; Paetzold, Martin; Piccioni, Giuseppe; Markiewicz, Wojciech; Vandaele, Ann C.; Wilson, Colin; Bertaux, Jean-Loup

    Since April 2006 ESA’s Venus Express has been performing a global survey of the remarkably dense, cloudy, and dynamic atmosphere of our near neighbour. The mission delivers comprehensive data on the temperature structure, the atmospheric composition, the cloud morphology, the atmospheric dynamics, the solar wind interaction and the escape processes. Vertical profiles of the atmospheric temperature show strong latitudinal trend in the mesosphere and upper troposphere correlated with changes in the cloud top structure and indicate convective instability in the main cloud deck at 50-60 km. Observations reveal significant latitudinal variations and temporal changes in the global cloud top morphology, which 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, correlated with decrease of the aerosol scale height from 4±1.6 km to 1.7±2.4 km, marking vast polar depression. UV imaging shows for the first time 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 dynamics. Solar occultation observations and deep atmosphere spectroscopy in spectral transparency windows mapped the distribution of the major trace gases H _{2}O, SO _{2}, CO, COS and their variations above and below the clouds, revealing key features of the dynamical and chemical processes at work. Tracking motions of cloud features provided the most complete characterization of the mean atmospheric circulation as well as its variability. Low and middle latitudes show an almost constant zonal wind speed at the cloud tops and vertical wind shear of 2-3 m/s/km. The zonal wind speed increased from 84±20 m/s to 110±16 m/s over the course of the mission. Towards the pole, the wind speed drops quickly and the vertical shear vanishes. The meridional poleward wind ranges from 0 at equator to about 15 m/s in

  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. Venus geology

    NASA Technical Reports Server (NTRS)

    Mclaughlin, W. I.

    1991-01-01

    The Magellan mission to Venus is reviewed. The scientific investigations conducted by 243-day cycles encompass mapping with a constant incidence angle for the radar, observing surface changes from one cycle to the next, and targeting young-looking volcanos. The topography of Venus is defined by the upper boundary of the crust and upwelling from lower domains. Tectonic features such as rift zones, linear mountain belts, ridge belts, and tesserae are described. The zones of tesserae are unique to the planet. Volcanism accounts for about 80 percent of the observed surface, the remainder being volcanic deposits which have been reworked by tectonism or impacts. Magellan data reveal about 900 impact craters with flow-like ejecta resulting from the fall of meteoroids. It is concluded that the age of the Venusian surface varies between 0 and 800 million years. Tectonic and volcanic activities dominate the formation of the Venus topography; such processes as weathering and erosion are relatively unimportant on Venus.

  19. Venus geology

    NASA Astrophysics Data System (ADS)

    McLaughlin, W. I.

    1991-05-01

    The Magellan mission to Venus is reviewed. The scientific investigations conducted by 243-day cycles encompass mapping with a constant incidence angle for the radar, observing surface changes from one cycle to the next, and targeting young-looking volcanos. The topography of Venus is defined by the upper boundary of the crust and upwelling from lower domains. Tectonic features such as rift zones, linear mountain belts, ridge belts, and tesserae are described. The zones of tesserae are unique to the planet. Volcanism accounts for about 80 percent of the observed surface, the remainder being volcanic deposits which have been reworked by tectonism or impacts. Magellan data reveal about 900 impact craters with flow-like ejecta resulting from the fall of meteoroids. It is concluded that the age of the Venusian surface varies between 0 and 800 million years. Tectonic and volcanic activities dominate the formation of the Venus topography; such processes as weathering and erosion are relatively unimportant on Venus.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Venus: Not evil, jus t a bit unfortunate

    NASA Astrophysics Data System (ADS)

    Taylor, Fw

    2010-02-01

    The Venus Express mission, currently orbiting Earth's nearest planetary neighbour, has just had its mission extended until the end of 2012 by the European Space Agency (ESA). In December 2010 it will be joined by the Japanese Venus Climate Orbiter, which has similar goals of understanding the atmosphere and climate. In this article Fred Taylor looks at what has been learned so far and what remains mysterious about our nearby twin, with its torrid weather and its global warming issues.

  5. 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.

  6. 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.

  7. Sprites and lightning in Venus: constraints for observations by the Planet-C mission

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Yair, Y.; Goto, Y.; Sentman, D.; Yoshida, J.; Sato, M.; Hoshino, N.

    2007-12-01

    Lightning activity in Venus has been mystery for long period, although many studies based on observations both by spacecrafts and by ground-based telescope have been carried out. This situation may be attributed to the ambiguity of these evidential measurements. In order to conclude this controversial subject, we are developing a new type of lightning detector, LAC (Lightning and Airglow Camera), which will be onboard Planet-C (Venus Climate Orbiter: VCO). PLanet-C will be launched in 2010 by JAXA. To distinguish optical lightning flash from other pulsing noises, high-speed sampling at 50kHz for each pixel, that enables us to investigate the time variation of each lightning flash phenomenon, is adopted. On the other hand, spatial resolution is not first priority. For this purpose we developed new type of APD (avalanche photo diode) array with a format of 8 x 8. Narrow band interference filter at wavelength of 777.4 nm (OI), which is expected lightning color based on laboratory discharge experiment, is chosen for lightning measurement. LAC detects lightning flash with an optical intensity of average of Earth's lightning or less at a distance of 3 Rv. We also present results of theoretical calculations of the expected occurrance heights and emissions of sprites above thunderstorms in the CO2 atmosphere of Venus and the Hydrogen-Helium atmospheres of Jupiter and Saturn. General detection methodology of sprites/lightning in planetary atmospheres by orbiting spacecraft will be discussed.

  8. 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.

  9. 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.

  10. 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.

  11. Dayside temperatures in the Venus upper atmosphere from Venus Express/VIRTIS nadir measurements at 4.3 μm

    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 μm 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

  12. Spacecraft VLBI and Doppler tracking of Venus Express

    NASA Astrophysics Data System (ADS)

    Molera Calves, G.; Cimo, G.; Duev, D. A.; Bocanegra-Bahamón, T.; Pogrebenko, S. V.; Gurvits, L. I.

    2012-09-01

    High-accurate Doppler tracking combined with Very Long Baseline Interferometry (VLBI) phasereferencing techniques are used for determination of the state vectors of planetary and deep space spacecraft missions. Ultra-precise estimates of the position and velocity of spacecraft can address to a wide range of research fields. The group has demonstrated successful detections on planetary flybys, landing of probes, drag acceleration measurements, and characterization of the interplanetary plasma.

  13. Context Images for Venus Express Radio Occultations: a Search for a Dynamical-Convective Origin of Cloud-top UV Contrasts

    NASA Astrophysics Data System (ADS)

    Roos-Serote, M.; Wilson, C. F.; MacDonald, R.; Tellmann, S.; Häusler, B.; Lee, Y. J.; Khatuntsev, I.

    2015-12-01

    It has been known for many decades that Venus shows strong contrasts when observed at UV wavelengths, as opposed to longer wavelengths in the visible and NIR, where Venus looks very homogeneous. This has been explained by the presence of a so-called UV absorber, which chemical identity is still unclear. Two hypothesis concerning the source and distribution of the UV-absorber have been put forward. For one of them the argument is that the absorbing substance is being transported from below the clouds up to the cloud top level by means of convection. This implies that in regions with more convection the absorber would be more abundant at the cloud-tops, thus resulting in lower brightness when observed in the UV. In the other scenario, it is haze-forming material which is brought to the cloud-tops by convection; in this case regions with stronger convection produce higher cloud tops would therefore show brighter in the UV.The premise behind the current analysis is to combine data from the Venus Express Radio Science experiment (VeRa) and from the Venus Monitoring Camera (VMC), to search for any correlation between the temperature structure (Tz and static stability, Sz) as sounded on one specific location and the UV brightness of that same location.Between 25 November and 31 December 2013 a special observing "South Polar Dynamics" campaign was performed with Venus Express. On each orbit one VeRa atmosphere sounding was acquired shortly after the pericentre passage, as well as a series of VMC-UV images capturing the very VeRa sounding location on that orbit before and after the sounding as it moves across the planet pushed by the zonal and meridional winds. Additional data was found from the another 42 orbits from entire mission Venus Express data set. The sounded latitudes varied between 0˚and -83º.The question is whether or not we can identify any statistically significant correlations between the temperature structure at a given location and the relative UV

  14. 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

  15. Solar wind interaction with Venus and impact on its atmosphere

    NASA Astrophysics Data System (ADS)

    Barabash, S.; Futaana, Y.; Wieser, G. S.; Luhmann, J.

    2014-04-01

    We present a review of the solar wind interaction with Venus and how the interaction affects the Venusian atmosphere. The Venus Express observations for more than 8 years (2005-present) and quantitatively new simulation codes substantially advanced physical understanding of the plasma processes in the near-Venus space since the Pioneer Venus Orbiter (PVO) mission (1978-1992). The near-Venus space can be divided into several plasma domains: the magnetotail with the plasmasheet, induced magnetosphere, and magnetosheath. The bow shock separates the undisturbed solar wind from the Venus-affected environment. We review the shapes and positions of the boundaries enveloping the main domains and discuss how they are formed by the current systems and pressure balance. In particular, we discuss the morphology and dynamics of the near-Venus magnetotail that was not accessible by PVO. Using the unique Venus Express measurements we discuss the ion acceleration processes and their links to the ionosphere. The focus is given to the Venus' atmosphere erosion associated with the solar wind interaction, both through the energy (ion acceleration) and momentum (atmospheric sputtering) transfer. We review the measurements of the escape rates, their variability with the upstream solar wind conditions and the solar cycle. We emphasize the measurements duirng extreme solar wind conditions as an analogue with nominal conditions for the young Sun. The modeling efforts in this area are also reviewed as they provide a quantitatively approach to understand the impact of the solar wind interaction on the atmospheric evolution. Finally, we compare Venus with other planets of the terrestrial planet group, the Earth and Mars. The Earth, a twin planet of the similar size, is magnetized. Mars, an unmagnetized planet like Venus, possesses by far weaker gravitation to hold its atmospheric gasses. This comparative magnetosphere approach based on the natural solar system laboratory of experiments gives

  16. 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

  17. New Interface for Accessing Archived European Space Agency Planetary Science Data, Such as the New Venus Express Atmospheric Drag Experiment Data Set

    NASA Astrophysics Data System (ADS)

    Grotheer, E.; Barbarisi, I.; Rios, C.; Macfarlane, A. J.; Docasal, R.; Arviset, C.; Besse, S.; Heather, D.; Gonzalez, J.; De Marchi, G.; Martinez, S.; Lim, T.; Fraga, D.

    2015-12-01

    All Venus Express (VEX) instruments delivered their data products according to the Planetary Data System version 3 (PDS3) standard, and the atmospheric drag experiment (ADE) data was no exception. The European Space Agency's (ESA) Planetary Science Archive (PSA), which can be accessed at www.rssd.esa.int/PSA, is being upgraded to make PDS4 data available from newer missions such as ExoMars and BepiColombo. Thus, the PSA development team has been working to ensure that the legacy PDS3 data will be accessible via the new interface as well. We will preview some of the new methods of accessing legacy VEX data via the new interface, with a focus being placed on the ADE data set. We will show how the ADE data can be accessed using Geographic Information Systems (GIS) and our plans for making this and other data sets compatible with the Virtual European Solar and Planetary Access (VESPA) project for creating a virtual observatory. From February 2010 through March 2014, ESA's Venus Express mission conducted 11 ADE campaigns. During these observation campaigns, VEX's pericenter was in the range of 165 to 190 km, while the spacecraft was near Venus' North pole, and the entire spacecraft was used to make in situ measurements of the atmospheric density. This was done by rotating the solar panels in a manner that somewhat resembles a windmill. Also, VEX 's attitude and orbit control system was tasked with maintaining the spacecraft in a 3-axis stabilized mode during these pericenter passes. The torques that the reaction wheels had to exert to maintain this attitude were then analyzed to yield density readings.

  18. 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

  19. 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.

  20. 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

  1. ESA Venus Entry Probe Study

    NASA Technical Reports Server (NTRS)

    vandenBerg, M. L.; Falkner, P.; Phipps, A.; Underwood, J. C.; Lingard, J. S.; Moorhouse, J.; Kraft, S.; Peacock, A.

    2005-01-01

    The Venus Entry Probe is one of ESA s Technology Reference Studies (TRS). The purpose of the Technology Reference Studies is to provide a focus for the development of strategically important technologies that are of likely relevance for future scientific missions. The aim of the Venus Entry Probe TRS is to study approaches for low cost in-situ exploration of Venus and other planetary bodies with a significant atmosphere. In this paper, the mission objectives and an outline of the mission concept of the Venus Entry Probe TRS are presented.

  2. 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.

  3. Habitats for life in the Venusian Environment? Can the VENUS EXPRESS payload answer?

    NASA Astrophysics Data System (ADS)

    Muller, C.

    2003-04-01

    The Venusian conditions are unique in the solar system. Venus abounds in molecules which could feed a life form except that the usual missing factor, energy, is present in excessive amounts from both active geothermic phenomena and from the nearby solar radiation trapped in a dense carbon dioxide atmosphere. Its surface conditions are hotter than the best practiced in hospital sterilisation; volcanism injects highly toxic gases which in the absence of water can accumulate in the atmosphere. Its upper atmosphere lays bare to solar radiation with only carbon dioxide to act as a confirmed EUV filter, so any consideration of life might seem excessive compared to what was known from life on earth before extremophile bacterias were discovered in dark undersea high temperature sulphur rich volcanic vents. However, some regions of the atmosphere might show conditions similar to the earth surface and could be a habitat of earth like microbial life. A synergy between the different atmospheric instruments of the VENUS-Express payload: SPICAM, VIRTIS and PFS can provide the way to probe the actual environmental conditions of this region and to check its capabilities of preserving an extant life or providing nutrients to a new one.

  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

  6. Initial Venus Express magnetic field observations of the magnetic barrier at solar minimum

    NASA Astrophysics Data System (ADS)

    Zhang, T. L.; Delva, M.; Baumjohann, W.; Volwerk, M.; Russell, C. T.; Barabash, S.; Balikhin, M.; Pope, S.; Glassmeier, K.-H.; Wang, C.; Kudela, K.

    2008-05-01

    Although there is no intrinsic magnetic field at Venus, the convected interplanetary magnetic field piles up to form a magnetic barrier in the dayside inner magnetosheath. In analogy to the Earth's magnetosphere, the magnetic barrier acts as an induced magnetosphere on the dayside and hence as the obstacle to the solar wind. It consists of regions near the planet and its wake for which the magnetic pressure dominates all other pressure contributions. The initial survey performed with the Venus Express magnetic field data indicates a well-defined boundary at the top of the magnetic barrier region. It is clearly identified by a sudden drop in magnetosheath wave activity, and an abrupt and pronounced field draping. It marks the outer boundary of the induced magnetosphere at Venus, and we adopt the name "magnetopause" to address it. The magnitude of the draped field in the inner magnetosheath gradually increases and the magnetopause appears to show no signature in the field strength. This is consistent with PVO observations at solar maximum. A preliminary survey of the 2006 magnetic field data confirms the early PVO radio occultation observations that the ionopause stands at ˜250 km altitude across the entire dayside at solar minimum. The altitude of the magnetopause is much lower than at solar maximum, due to the reduced altitude of the ionopause at large solar zenith angles and the magnetization of the ionosphere. The position of the magnetopause at solar minimum is coincident with the ionopause in the subsolar region. This indicates a sinking of the magnetic barrier into the ionosphere. Nevertheless, it appears that the thickness of the magnetic barrier remains the same at both solar minimum and maximum. We have found that the ionosphere is magnetized ˜95% of the time at solar minimum, compared with 15% at solar maximum. For the 5% when the ionosphere is un-magnetized at solar minimum, the ionopause occurs at a higher location typically only seen during solar

  7. Priorities for Venus Exploration

    NASA Astrophysics Data System (ADS)

    Glaze, L. S.; Beauchamp, P. M.; Chin, G.; Crisp, D.; Grimm, R. E.; Herrick, R. R.; Johnston, S.; Limaye, S. S.; Smrekar, S. E.; Ocampo, A.; Thompson, T. W.

    2013-12-01

    Venus remains one of the most enigmatic bodies in our Solar System. Important questions remain regarding the origin and evolution of the atmosphere, the history of the surface and interior, and how the surface and atmosphere interact. In a broader context, understanding Venus has implications for understanding the evolution of terrestrial planets in our Solar System as well as for interpreting the growing set of observations of extra-solar planets. The Venus Exploration Analysis Group (VEXAG), established in 2005, is chartered by NASA's Planetary Science Division and reports its findings to the NASA Advisory Council. Open to all interested scientists, VEXAG regularly evaluates Venus exploration goals, scientific objectives, investigations and critical measurement requirements, including especially recommendations in the NRC Decadal Survey and the Solar System Exploration Strategic Roadmap. At the last general meeting in November 2012, VEXAG resolved to update the scientific priorities and strategies for Venus exploration. To achieve this goal, three major tasks were defined for 2013, (1) update the document prioritizing Goals, Objectives and Investigations for Venus Exploration, (2) develop a Roadmap for Venus exploration that is consistent with VEXAG priorities as well as Planetary Decadal Survey priorities, and (3) develop a white paper on technologies for Venus missions. Proposed versions of all three documents were presented at the VEXAG general meeting in November 2013. Here, we present the findings and final versions of all three documents for community comment and feedback. A follow-on Workshop on Venus Exploration Targets is also being planned for the early summer of 2014. The workshop will provide a forum for the Venus science community to discuss approaches for addressing high priority investigations. Participants will be encouraged to present their ideas for specific targets on Venus (interior, surface and atmosphere) as well as to present specific data

  8. Progress towards a Venus reference cloud model

    NASA Astrophysics Data System (ADS)

    Wilson, Colin; Ignatiev, Nikolay; Marcq, Emmanuel

    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. We have formed an International Team at the International Space Science Institute to bring together scientists from each of the relevant Venus Express investigation teams as well as from previous missions, as well as those developing computational and analytical models of clouds and hazes. The aims of the project are (1) to create self-consistent reference cloud/haze models which capture not only a mean cloud structure but also its main modes of variability; and (2) to bring together modelers and observers, to reach an understanding of clouds and hazes on Venus which matches all observables and is physically consistent. Our approach is to first to assemble an averaged cloud profile for low latitudes, showing how cloud number abundances and other observables vary as a function of altitude, consistent with all available observations. In a second step, we will expand this work to produce a reference cloud profile which varies with latitude and local solar time, as well as optical thickness of the cloud. We will present our status in progressing towards this goal. We acknowledge the support of the International Space Science Institute of Berne, Switzerland, in hosting our Team’s meetings.

  9. 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.

  10. 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.

  11. Venus - Ushas Mons

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This area of Venus northeast of Ushas Mons measures 40 by 112 kilometers (25 by 70 miles) and shows evidence of possible explosive volcanism. A surface deposit that shows brightly in radar extends and broadens away from the 1 kilometer diameter (0.6 mile diameter) crater in the middle of the image. The deposit is brighter near the crater, fades gradually into the plains and ends about 10 kilometers (6 miles) from the crater. The underlying crisscross pattern becomes more visible away from the crater as the covering deposit thins out. These characteristics are typical of deposits on Earth formed by fallout from volcanic explosion plumes. A similar but darker deposit extends to the right of the crater. The crater on the western edge of the image also shows similar deposits. North is at the top of the image. The Magellan Mission Magellan is a NASA spacecraft mission to map the surface of Venus with imaging radar. The basic scientific instrument is a synthetic aperture radar, or SAR, which can look through the thick clouds perpetually shielding the surface of Venus. Magellan is in orbit around Venus which completes one turn around its axis in 243 Earth days. That period of time, one Venus day, is the length of Magellan's primary mission. During that time Magellan will map about 80 percent of the Venus surface. Subsequent missions of equal duration will provide complete mapping of the planet. Magellan was launched May 4, 1989, aboard the space shuttle Atlantis and went into orbit around Venus August 10, 1990. The spacecraft completes one orbit every three hours and 15 minutes, passing as close to the planet as 294 kilometers (183 miles) and as far away from Venus as 8,472 kilometers (5,265 miles). The smallest objects seen in this image measure approximately 120 meters (400 feet).

  12. Hypothetical habitability of Venus

    NASA Astrophysics Data System (ADS)

    Ksanfomality, Leonid

    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.

  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. 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-κB 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-κB pathway. PMID:26115685

  15. Venusian ion populations and bow shock as seen by the ASPERA-4 ion instrument on Venus Express

    NASA Astrophysics Data System (ADS)

    Grande, M.; Whittaker, I.; Guymer, G.; Barabash, S.

    2008-09-01

    Introduction We examine ion populations at Venus. Previous models use magnetic crossing points to derive the bow shock position. The current work uses data from the ASPERA-4 (Analyser of Space Plasmas and Energetic Atoms) [1] instrument to measure ion populations and derive a bow shock position at Venus. Instrumentation The ASPERA-4 instrument flies onboard Venus Express (VEX) and is comprised of five different detectors (Barabash et al 2006 [1]). A neutral particle detector and analyser, an electron spectrometer and the Ion Mass Analyser (IMA) (ref). This paper uses the IMA instrument for all its data and an explanation of the specifications is required. The instrument is a top hat electrostatic analyser; it runs through voltages to scan look angles and also acceptance energies. In one look direction it scans through 96 different energy values before changing to the next. A full scan of all look directions and energies takes 192 seconds. Data Collection All data is weighed dependant upon its probability of the spacecraft measuring at a particular point and when fitted produces a value of 1.24 RV, somewhat closer distance for the sub solar point than previous authors - see figure 1. We separate the data according to slow or fast solar wind and not the similarities and differences in the results derived. The inbound and outbound bow shock crossings were taken by inspection of 106 orbits between November 2006 and February 2007. Any orbits where the crossing point was not clear or with data missing were ignored. The occupational probability is found from orbital mechanics. By setting up a grid and deriving the amount of time it takes to cross each square the probability as a whole can then be determined. Ion distribution plots Two dimensional maps of the ions are produced and the bow shock model overplotted to verify its accuracy, as shown in figure 3. The test of the bow shock is to place it upon real data and examine the fit. To do this ion distribution plots are

  16. In situ observations of waves in Venus’s polar lower thermosphere with Venus Express aerobraking

    NASA Astrophysics Data System (ADS)

    Müller-Wodarg, Ingo C. F.; Bruinsma, Sean; Marty, Jean-Charles; Svedhem, Håkan

    2016-08-01

    Waves are ubiquitous phenomena found in oceans and atmospheres alike. From the earliest formal studies of waves in the Earth’s atmosphere to more recent studies on other planets, waves have been shown to play a key role in shaping atmospheric bulk structure, dynamics and variability. Yet, waves are difficult to characterize as they ideally require in situ measurements of atmospheric properties that are difficult to obtain away from Earth. Thus, we have incomplete knowledge of atmospheric waves on planets other than our own, and we are thereby limited in our ability to understand and predict planetary atmospheres. Here we report the first ever in situ observations of atmospheric waves in Venus’s thermosphere (130-140 km) at high latitudes (71.5°-79.0°). These measurements were made by the Venus Express Atmospheric Drag Experiment (VExADE) during aerobraking from 24 June to 11 July 2014. As the spacecraft flew through Venus’s atmosphere, deceleration by atmospheric drag was sufficient to obtain from accelerometer readings a total of 18 vertical density profiles. We infer an average temperature of T = 114 +/- 23 K and find horizontal wave-like density perturbations and mean temperatures being modulated at a quasi-5-day period.

  17. 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.

  18. 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.

  19. Hydrogen density in the dayside venusian exosphere derived from Lyman-α observations by SPICAV on Venus Express

    NASA Astrophysics Data System (ADS)

    Chaufray, J.-Y.; Bertaux, J.-L.; Quémerais, E.; Villard, E.; Leblanc, F.

    2012-02-01

    A series of observations of the venusian hydrogen corona made by SPICAV on Venus Express are analyzed to estimate the amount of hydrogen in the exosphere of Venus. These observations were made between November 2006 and July 2007 at altitudes from 1000 km to 8000 km on the dayside. The Lyman-α brightness profiles derived are reproduced by the sum of a cold hydrogen population dominant below ˜2000 km and a hot hydrogen population dominant above ˜4000 km. The temperature (˜300 K) and hydrogen density at 250 km (˜10 5 cm -3) derived for the cold populations, near noon, are in good agreement with previous observations. Strong dawn-dusk exospheric asymmetry is observed from this set of observations, with a larger exobase density on the dawn side than on the dusk side, consistent with asymmetry previously observed in the venusian thermosphere, but with a lower dawn/dusk contrast. The hot hydrogen density derived is very sensitive to the sky background estimate, but is well constrained near 5000 km. The density of the hot population is reproduced by the exospheric model from Hodges (Hodges, R.R. [1999]. J. Geophys. Res. 104, 8463-8471) in which the hot population is produced by neutral-ions interactions in the thermosphere of Venus.

  20. Venus cartography

    NASA Astrophysics Data System (ADS)

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

    1994-10-01

    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 sea-floors. The mapping is designed to support geologic and geophysical investigations.

  1. 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.

  2. Vertical structure of Venus polar thermosphere from in-situ data of the Venus Express Atmospheric Drag Experiment (VExADE)

    NASA Astrophysics Data System (ADS)

    Mueller-Wodarg, Ingo; Svedhem, Håkan; Bruinsma, Sean; Gurvits, Leonid; Cimo, Giuseppe; Molera Calves, Guifre; Bocanegra Bahamon, Tatiana; Rosenblatt, Pascal; Duev, Dmitry; Marty, Jean-Charles; Progebenko, Sergei

    The Venus Express Atmospheric Drag Experiment (VExADE) has enabled first ever in-situ measurements of the density of the near-polar thermosphere of Venus above an altitude of 165 km. The measured values have been compared with existing models such as VTS3, which has been built mainly with the Pioneer Venus Orbiter Mass Spectrometer (PV-ONMS) data taken near 16˚ latitude, but extrapolated globally. The VExADE density values have been derived from the Precise Orbit Determination (POD) of the VEx spacecraft using both navigation and dedicated tracking data around pericenter passes during several VExADE campaigns. The last campaign has also benefited from the Planetary Radio Interferometry and Doppler Experiment (PRIDE) tracking. The combination of POD techniques has provided 46 reliable estimates of the polar thermosphere density. An independent set of density measurements was also taken by inferring the torque of the VEx spacecraft exerted by Venus’ upper atmosphere on the spacecraft during pericenter passes. This method has provided more than 120 density values in remarkably good agreement with the density values provided by the POD method. To date, the VExADE data have probed a range of 160 to 185 km in altitude, 80 to 90 degrees North in latitude and 5 to 20 hours in local time. While sampling in these ranges is insufficient to establish detailed horizontal density structures of the polar thermosphere a set of important properties can be inferred. First, the densities are lower by a factor of around 1.5 than the densities predicted by VTS3. At the same time, we find the density scale heights of VExADE and VTS3 to be consistent. Second, the density values exhibit strong variability, which is not taken into account in the VTS3 model. In order to investigate this dynamical behavior of the polar thermosphere, the ratio between the VExADE and VTS3 density has been analyzed. The latitude, altitude and local time trends are tentatively identified, but the sparse

  3. 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

  4. 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.

  5. Geologic Analysis of the Surface Thermal Emission Images Taken by the VMC Camera, Venus Express

    NASA Astrophysics Data System (ADS)

    Basilevsky, A. T.; Shalygin, E. V.; Titov, D. V.; Markiewicz, W. J.; Scholten, F.; Roatsch, Th.; Fiethe, B.; Osterloh, B.; Michalik, H.; Kreslavsky, M. A.; Moroz, L. V.

    2010-03-01

    Analysis of Venus Monitoring Camera 1-µm images and surface emission modeling showed apparent emissivity at Chimon-mana tessera and shows that Tuulikki volcano is higher than that of the adjacent plains; Maat Mons did not show any signature of ongoing volcanism.

  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. The role of magnetospheric energy sources on Titan and Venus: A comparative evaluation

    NASA Astrophysics Data System (ADS)

    Mueller-Wodarg, I.; Yelle, R.; Cui, J.; Galand, M.

    2010-05-01

    The atmospheres of Venus and Titan on one level share many similarities, but at the same time host interesting differences which motivate a more comprehensive comparison. As a result of highly successful missions like Pioneer Venus and Venus Express, the atmosphere of Venus is the most extensively observed planetary atmosphere apart from the Earth's. The ongoing tour of Cassini-Huygens has led to a vast increase in our knowledge and understanding of Titan's atmosphere, but important information gaps remain. How much can we learn from Venus when attempting to understand the upper atmosphere of Titan? One fundamental question to address is that of the global energy balance in the atmosphere of Titan, and in particular in the upper atmosphere (thermosphere/ionosphere region), which in turns drives the global dynamics and affects the neutral and ion species distribution. One potentially important energy source on Titan derives from magnetosphere-atmosphere coupling by a combination of energetic particle precipitation and the closing of magnetospheric currents in the ionosphere. As a result of weaker solar forcing at Titan, these magnetospheric energy sources may play a comparatively stronger factor in driving the global energy balance and thereby dynamics on Titan than they do on Venus. This paper will evaluate the energy balance on Venus and Titan by assessing the ease at which numerical models driven by solar heating reproduce observed thermosphere densities. We will discuss the relative roles of solar and magnetospheric energy sources on Venus and Titan and outline the wider consequences of their differences.

  8. 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.

  9. Simulations of Wave Features in Venus' Deep Atmosphere Associated with Topography, Using a Venus GCM

    NASA Astrophysics Data System (ADS)

    Parish, H. F.

    2015-12-01

    Venus' cloud-level atmosphere is characterized by the presence of waves with a range of periods and scale sizes. Wave phenomena can have important dynamical effects and may deposit significant momentum and energy into the atmosphere. Fluctuations with scale sizes of a few km to 10's of km have been observed at cloud altitudes in temperatures, winds or UV images from Mariner 10, Pioneer Venus, Venera 9, Magellan and Venus Express, suggesting the presence of gravity waves. Measurements of Venus' cloud level atmosphere have also identified planetary scale waves, with periods of around 4 to 5 days, which have been associated with Rossby or Kelvin waves. Longer term variations have also been observed in wind velocities at cloud heights, with periods of the order of several years. Planetary scale waves or gravity waves at cloud altitudes may be generated by a number of different mechanisms, for example by instabilities such as the Kelvin-Helmholtz instability or convective instability below the upper cloud layer, or they may be generated at lower altitudes and propagate upwards. Recent analyses from Venus Express observations suggest an association of gravity waves at cloud heights with significant topographical features. Although many measurements are available at cloud altitudes, little is known about waves in the poorly measured deep atmosphere. In order to explore the characteristics of waves generated near the surface we perform numerical simulations using the Venus Community Atmosphere Model general circulation model, which includes realistic topography based on measurements from the Magellan mission. We examine the influence of topography in generating waves near the surface associated with topographical features and the vertical development of simulated waves.

  10. 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

  11. On ion escape from Venus

    NASA Astrophysics Data System (ADS)

    Jarvinen, Riku

    2011-04-01

    This doctoral thesis is about the solar wind influence on the atmosphere of the planet Venus. A numerical plasma simulation model was developed for the interaction between Venus and the solar wind to study the erosion of charged particles from the Venus upper atmosphere. The developed model is a hybrid simulation where ions are treated as particles and electrons are modelled as a fluid. The simulation was used to study the solar wind induced ion escape from Venus as observed by the European Space Agency's Venus Express and NASA's Pioneer Venus Orbiter spacecraft. Especially, observations made by the ASPERA-4 particle instrument onboard Venus Express were studied. The thesis consists of an introductory part and four peer-reviewed articles published in scientific journals. In the introduction Venus is presented as one of the terrestrial planets in the Solar System and the main findings of the work are discussed within the wider context of planetary physics. Venus is the closest neighbouring planet to the Earth and the most earthlike planet in its size and mass orbiting the Sun. Whereas the atmosphere of the Earth consists mainly of nitrogen and oxygen, Venus has a hot carbon dioxide atmosphere, which is dominated by the greenhouse effect. Venus has all of its water in the atmosphere, which is only a fraction of the Earth's total water supply. Since planets developed presumably in similar conditions in the young Solar System, why Venus and Earth became so different in many respects? One important feature of Venus is that the planet does not have an intrinsic magnetic field. This makes it possible for the solar wind, a continuous stream of charged particles from the Sun, to flow close to Venus and to pick up ions from the planet's upper atmosphere. The strong intrinsic magnetic field of the Earth dominates the terrestrial magnetosphere and deflects the solar wind flow far away from the atmosphere. The region around Venus where the planet's atmosphere interacts with the

  12. On ion escape from Venus

    NASA Astrophysics Data System (ADS)

    Jarvinen, R.

    2011-04-01

    This doctoral thesis is about the solar wind influence on the atmosphere of the planet Venus. A numerical plasma simulation model was developed for the interaction between Venus and the solar wind to study the erosion of charged particles from the Venus upper atmosphere. The developed model is a hybrid simulation where ions are treated as particles and electrons are modelled as a fluid. The simulation was used to study the solar wind induced ion escape from Venus as observed by the European Space Agency's Venus Express and NASA's Pioneer Venus Orbiter spacecraft. Especially, observations made by the ASPERA-4 particle instrument onboard Venus Express were studied. The thesis consists of an introductory part and four peer-reviewed articles published in scientific journals. In the introduction Venus is presented as one of the terrestrial planets in the Solar System and the main findings of the work are discussed within the wider context of planetary physics.Venus is the closest neighbouring planet to the Earth and the most earthlike planet in its size and mass orbiting the Sun. Whereas the atmosphere of the Earth consists mainly of nitrogen and oxygen, Venus has a hot carbon dioxide atmosphere, which is dominated by the greenhouse effect. Venus has all of its water in the atmosphere, which is only a fraction of the Earth's total water supply. Since planets developed presumably in similar conditions in the young Solar System, why Venus and Earth became so different in many respects?One important feature of Venus is that the planet does not have an intrinsic magnetic field. This makes it possible for the solar wind, a continuous stream of charged particles from the Sun, to flow close to Venus and to pick up ions from the planet's upper atmosphere. The strong intrinsic magnetic field of the Earth dominates the terrestrial magnetosphere and deflects the solar wind flow far away from the atmosphere. The region around Venus where the planet's atmosphere interacts with the

  13. Radar observation of Venus' terrestrial analogues using TecSAR X-band SAR

    NASA Astrophysics Data System (ADS)

    Blumberg, D. G.

    2012-04-01

    Venus is shrouded in a dense CO2 atmosphere that prevents us from viewing the surface in visible light or with optronic sensors. Long wavelengths are required to 'see' through the dense atmosphere. In the early 1990s, the S-band synthetic aperture radar of the Magellan spacecraft acquired images of a variety of surface features on Venus, including morphologies attributed to wind processes. These include sand dunes, wind-sculpted hills (yardangs), and almost 6000 wind streaks. These aeolian landscapes were formed and shaped by near surface atmospheric circulation and local winds. These can serve as local markers, each providing an integrated wind direction. Since the Magellan mission, there were no missions to Venus until the Venus Express Mission of 2005 to examine the upper atmosphere. The future will probably include high-resolution SAR images of Venus. This poster will demonstrate high resolution SAR images in X-band from the TecSAR sensor launched by Israel in 2008. Observations of wind streaks, dunes and impact craters in desert areas will show the wealth of information that is extracted from high-res X-band data. Detailed images of Aurounga impact crater in Chad, Kelso dunes, California and Pisgah lava flow show immense detail of the morphologies associated with these features. These are compared with Magellan images of sites on Venus and SRL data in C and L-bands. The X-band provides extremely high resolution and resembles optical data much more than the longer wavelengths.

  14. 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

  15. [Establishment of goat limbal stem cell strain expressing Venus fluorescent protein and construction of limbal epithelial sheets].

    PubMed

    Yin, Jiqing; Liu, Wenqiang; Liu, Chao; Zhao, Guimin; Zhang, Yihua; Liu, Weishuai; Hua, Jinlian; Dou, Zhongying; Lei, Anmin

    2010-12-01

    The integrity and transparency of cornea plays a key role in vision. Limbal Stem Cells (LSCs) are precursors of cornea, which are responsible for self-renewal and replenishing corneal epithelium. Though it is successful to cell replacement therapy for impairing ocular surface by Limbal Stem Cell Transplantation (LSCT), the mechanism of renew is unclear after LSCT. To real time follow-up the migration and differentiation of corneal transplanted epithelial cells after transplanting, we transfected venus (a fluorescent protein gene) into goat LSCs, selected with G418 and established a stable transfected cell line, named GLSC-V. These cells showed green fluorescence, and which could maintain for at least 3 months. GLSC-V also were positive for anti-P63 and anti-Integrinbeta1 antibody by immunofluorescent staining. We founded neither GLSC-V nor GLSCs expressed keratin3 (k3) and keratinl2 (k12). However, GLSC-V had higher levels in expression of p63, pcna and venus compared with GLSCs. Further, we cultivated the cells on denude amniotic membrane to construct tissue engineered fluorescent corneal epithelial sheets. Histology and HE staining showed that the constructed fluorescent corneal epithelial sheets consisted of 5-6 layers of epithelium. Only the lowest basal cells of fluorescent corneal epithelial sheets expressed P63 analyzed by immunofluorescence, but not superficial epithelial cells. These results showed that our constructed fluorescent corneal epithelial sheets were similar to the normal corneal epithelium in structure and morphology. This demonstrated that they could be transplanted for patents with corneal impair, also may provide a foundation for the study on the mechanisms of corneal epithelial cell regeneration after LSCT. PMID:21387825

  16. 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.

  17. 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

  18. 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.

  19. 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.

  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. 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.

  2. Aeolian processes on Venus

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    1989-01-01

    This review assesses the potential aeolian regime on Venus as derived from spacecraft observations, laboratory simulations, and theoretical considerations. The two requirements for aeolian processes (a supply of small, loose particles and winds of sufficient strength to move them) appear to be met on Venus. Venera 9, 10, 13, and 14 images show particles considered to be sand and silt size on the surface. In addition, dust spurts (grains 5 to 50 microns in diameter) observed via lander images and inferred from the Pioneer-Venus nephalometer experiments suggest that the particles are loose and subject to movement. Although data on near surface winds are limited, measurements of 0.3 to 1.2 m/sec from the Venera lander and Pioneer-Venus probes appear to be well within the range required for sand and dust entrainment. Aeolian activity involves the interaction of the atmosphere, lithosphere, and loose particles. Thus, there is the potential for various physical and chemical weathering processes that can effect not only rates of erosion, but changes in the composition of all three components. The Venus Simulator is an apparatus used to simulate weathering under venusian conditions at full pressure (to 112 bars) and temperature (to 800 K). In one series of tests, the physical modifications of windblown particles and rock targets were assessed and it was shown that particles become abraded even when moved by gentle winds. However, little abrasion occurs on the target faces. Thus, compositional signatures for target rocks may be more indicative of the windblown particles than of the bedrock. From these and other considerations, aeolian modifications of the venusian surface may be expected to occur as weathering, erosion, transportation, and deposition of surficial materials. Depending upon global and local wind regimes, there may be distinctive sources and sinks of windblown materials. Radar imaging, especially as potentially supplied via the Magellan mission, may enable the

  3. 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.

  4. Return to Venus of the Japanese Venus Climate Orbiter AKATSUKI

    NASA Astrophysics Data System (ADS)

    Nakamura, Masato; Kawakatsu, Yasuhiro; Hirose, Chikako; Imamura, Takeshi; Ishii, Nobuaki; Abe, Takumi; Yamazaki, Atsushi; Yamada, Manabu; Ogohara, Kazunori; Uemizu, Kazunori; Fukuhara, Tetsuya; Ohtsuki, Shoko; Satoh, Takehiko; Suzuki, Makoto; Ueno, Munetaka; Nakatsuka, Junichi; Iwagami, Naomoto; Taguchi, Makoto; Watanabe, Shigeto; Takahashi, Yukihiro; Hashimoto, George L.; Yamamoto, Hiroki

    2014-01-01

    Japanese Venus Climate Orbiter/AKATSUKI was proposed in 2001 with strong support by international Venus science community and approved as an ISAS (The Institute of Space and Astronautical Science) mission soon after the proposal. The mission life we expected was more than two Earth years in Venus orbit. AKATSUKI was successfully launched at 06:58:22JST on May 21, 2010, 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' deployment was confirmed. After a successful cruise, the malfunction happened on the propulsion system during the Venus orbit insertion (VOI) on Dec. 7, 2010. The engine shut down before the planned reduction in speed to achieve. The spacecraft did not enter the Venus orbit but entered an orbit around the Sun with a period of 203 days. Most of the fuel still had remained, but the orbital maneuvering engine was found to be broken and unusable. However, we have found an alternate way of achieving orbit by using only the reaction control system (RSC). We had adopted the alternate way for orbital maneuver and three minor maneuvers in Nov. 2011 were successfully done so that AKATSUKI would meet Venus in 2015. We are considering several scenarios for VOI using only RCS.

  5. 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

  6. 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)

  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. Venus Syndrome

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Kharecha, P.; Lacis, A.; Russell, G.; Sato, M.

    2012-06-01

    We use three alternative avenues to investigate climate sensitivity on Earth and the conditions that could lead to extermination of human life on the planet or even a Venus-like runaway greenhouse effect.

  9. Thermal Structure and Radiative Balance of the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Limaye, S. S.

    2014-04-01

    Venus Express, observing since April 2006 has returned a wealth of useful information about the atmospheric temperature and density structure of the planet. New and refined instruments have advanced not only the accuracy but also the altitude range of the inferred structure. With multiple experiments on Venus Express contributing to the inferred vertical structure, there is overlap in some altitude regions, allowing and requiring conciliation of the inferred values in terms of spatial and temporal coverage as well as errors and biases. In addition, there are older spacecraft results as well as recent ground based observations that contribute to the new information about the thermal structure of the atmosphere. Regarding the radiative balance, we have new information about changes in the absorbed solar radiation over the duration of the Venus Express mission, but little new information in terms of the emitted radiation from the planet. A coordinated effort was initiated in late 2013 to assess these new data through an international team hosted by the International Space Studies Institute [1]. This solicited chapter for the Venus III book being developed at present [2] is based on the efforts of this group.

  10. Carbon monoxide observed in Venus' atmosphere with SOIR/VEx

    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.

    2016-07-01

    The SOIR instrument on board the ESA Venus Express mission has been operational during the complete duration of the mission, from April 2006 up to December 2014. Spectra were recorded in the IR spectral region (2.2-4.3 μm) using the solar occultation geometry, giving 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 the short term, but also the long term trend as well as variation of CO with solar local time and latitude. Short term variations can reach one order of magnitude on less than one month periods. SOIR does not observe a marked long term trend, except perhaps at the beginning of the mission where an increase of CO density and vmr has been observed. Evening abundances are systematically higher than morning values at altitudes above 105 km, but the reverse is observed at lower altitudes. Higher abundances are observed at the equator than at the poles for altitude higher than 105 km, but again the reverse is seen at altitudes lower than 90 km. This illustrates the complexity of the 90-100 km region of the Venus' atmosphere where different wind regimes are at play.

  11. The SPICAV-SOIR instrument probing the atmosphere of Venus: an overview

    NASA Astrophysics Data System (ADS)

    Trompet, Loïc; Mahieux, Arnaud; Wilquet, Valérie; Robert, Séverine; Chamberlain, Sarah; Thomas, Ian; Carine Vandaele, Ann; Bertaux, Jean-Loup

    2016-04-01

    The Solar Occultation in the Infrared (SOIR) channel mounted on top of the SPICAV instrument of the ESA's Venus Express mission has observed the atmosphere of Venus during more than eight years. This IR spectrometer (2.2-4.3 μm) with a high spectral resolution (0.12 cm-1) combined an echelle grating with an acousto-optic tunable filter for order selection. SOIR performed more than 1500 solar occultation measurements leading to about two millions spectra. The Royal Belgian Institute for Space Aeronomy (BIRA-IASB) was in charge of SOIR's development and operations as well as its data pipeline. BIRA-IASB carried out several studies on the composition of Venus mesosphere and lower thermosphere: carbon dioxide, carbon monoxide, hydrogen halide (HF, HCl, DF, DCl), sulfur dioxide, water (H2O, HDO) as well as sulphuric acid aerosols in the upper haze of Venus. Density and temperature profiles of the upper atmosphere of Venus (60 km to 170 km) at the terminator have been retrieved from SOIR's spectra using different assumptions, wherein the hydrostatic equilibrium and the local thermodynamical equilibrium in the radiative transfer calculations. These results allow us to produce an Atmospheric model of Venus called Venus Atmosphere from SOIR measurements at the Terminator (VAST). Data obtained by SOIR will also contribute to update the Venus International Reference Atmosphere (VIRA). Recently, the treatment of the raw data to transmittance has been optimized, and a new dataset of spectra has been produced. All raw spectra (PSA level 2) as well as calibrated spectra (PSA level 3) have been delivered to ESA's Planetary Science Archive (PDSPSA). Consequently the re-analysis of all spectra has been undergone. We will briefly present the improvements implemented in the data pipeline. We will also show a compilation of results obtained by the instrument considering the complete mission duration.

  12. Atmospheric structure and cloud properties on Venus

    NASA Astrophysics Data System (ADS)

    Zasova, L. V.

    temporary variable. Soviet and American missions investigated Venus in the past, European Venus Express is working successfully now, Japan mission Planet-C is preparing to be launch in 2007 and Venera-D mission is included in Russian Federal Space Program with launch around 2016.

  13. Venus Atmospheric Maneuverable Platform (VAMP)

    NASA Astrophysics Data System (ADS)

    Shapiro Griffin, Kristen L.; Sokol, D.; Dailey, D.; Lee, G.; Polidan, R.

    2013-10-01

    We have explored a possible new approach to Venus upper atmosphere exploration by applying Northrop Grumman (non-NASA) development programs to the challenges associated with Venus upper atmosphere science missions. Our concept is a low ballistic coefficient (<50 Pa), semi-buoyant aircraft that deploys prior to entering the Venus atmosphere, enters the atmosphere without an aeroshell, and provides a long-lived (months to years), maneuverable vehicle capable of carrying science payloads to explore the Venus upper atmosphere. In this presentation we report results from our ongoing study and plans for future analyses and prototyping. We discuss the overall mission architecture and concept of operations from launch through Venus arrival, orbit, entry, and atmospheric science operations. We present a strawman concept of VAMP, including ballistic coefficient, planform area, percent buoyancy, inflation gas, wing span, vehicle mass, power supply, propulsion, materials considerations, structural elements, subsystems, and packaging. The interaction between the VAMP vehicle and the supporting orbiter will also be discussed. In this context, we specifically focus upon four key factors impacting the design and performance of VAMP: 1. Feasibility of and options for the deployment of the vehicle in space 2. Entry into the Venus atmosphere, including descent profile, heat rate, total heat load, stagnation temperature, control, and entry into level flight 3. Characteristics of flight operations and performance in the Venus atmosphere: altitude range, latitude and longitude access, day/night performance, aircraft performance (aerodynamics, power required vs. power available, propulsion, speed, percent buoyancy), performance sensitivity to payload weight 4. Science payload accommodation, constraints, and opportunities We discuss interdependencies of the above factors and the manner in which the VAMP strawman’s characteristics affect the CONOPs and the science objectives. We show how

  14. 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.

  15. Hinode Views the 2012 Venus Transit

    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...

  16. Hinode Views the Transit of Venus

    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 ...

  17. 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

  18. Optimizing Aerobot Exploration of Venus

    NASA Technical Reports Server (NTRS)

    Ford, Kevin S.

    1997-01-01

    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.

  19. HAVOC: High Altitude Venus Operational Concept - An Exploration Strategy for Venus

    NASA Technical Reports Server (NTRS)

    Arney, Dale; Jones, Chris

    2015-01-01

    The atmosphere of Venus is an exciting destination for both further scientific study and future human exploration. A lighter-than-air vehicle can carry either a host of instruments and probes, or a habitat and ascent vehicle for a crew of two astronauts to explore Venus for up to a month. The mission requires less time to complete than a crewed Mars mission, and the environment at 50 km is relatively benign, with similar pressure, density, gravity, and radiation protection to the surface of Earth. A recent internal NASA study of a High Altitude Venus Operational Concept (HAVOC) led to the development of an evolutionary program for the exploration of Venus, with focus on the mission architecture and vehicle concept for a 30 day crewed mission into Venus's atmosphere. Key technical challenges for the mission include performing the aerocapture maneuvers at Venus and Earth, inserting and inflating the airship at Venus, and protecting the solar panels and structure from the sulfuric acid in the atmosphere. With advances in technology and further refinement of the concept, missions to the Venusian atmosphere can expand humanity's future in space.

  20. Venus gravity

    NASA Technical Reports Server (NTRS)

    Reasenberg, Robert D.

    1993-01-01

    The anomalous gravity field of Venus shows high correlation with surface features revealed by radar. We extract gravity models from the Doppler tracking data from the Pioneer Venus Orbiter (PVO) by means of a two-step process. In the first step, we solve the nonlinear spacecraft state estimation problem using a Kalman filter-smoother. The Kalman filter was evaluated through simulations. This evaluation and some unusual features of the filter are discussed. In the second step, we perform a geophysical inversion using a linear Bayesian estimator. To allow an unbiased comparison between gravity and topography, we use a simulation technique to smooth and distort the radar topographic data so as to yield maps having the same characteristics as our gravity maps. The maps presented cover 2/3 of the surface of Venus and display the strong topography-gravity correlation previously reported. The topography-gravity scatter plots show two distinct trends.

  1. 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.

  2. Venus Middle Atmosphere Chemistry

    NASA Astrophysics Data System (ADS)

    Mills, F. P.; Sundaram, M.; Slanger, T. G.; Allen, M.; Yung, Y. L.

    2005-08-01

    Venus is the most similar planet to Earth, and years of research have sought to understand their similarities and differences. Yet, it is still not clear what chemical processes maintain the long-term stability of Venus' primarily CO2 atmosphere. CO2 dissociates into CO and O after absorbing photons at wavelengths < 210 nm. These O atoms should combine to form O2, and observations of intense airglow confirm rapid production of O2 on both day and night sides. CO and O2 are sufficiently stable that an initially pure CO2 atmosphere would rapidly evolve to have 7-8% CO and 3.5-4% O2 [1]. The observed upper limit on O2 (0.3 ppm [2]), however, indicates catalytic mechanisms [3], rapidly convert CO and oxygen into CO2. The current understanding of Venus middle atmosphere chemistry, the state of lab data, and prospects for advances based on Venus Express will be reviewed. Recent work evaluating newly proposed mechanisms for producing CO2, which could be important depending on the rates of poorly constrained reactions, will be described. This research was supported by funding from NASA's Planetary Atmospheres program and the Australian Research Council. Part of this work was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. [1] Nair, et al., Icarus 111, 124 (1994), [2] Trauger and Lunine, Icarus 55, 272 (1983), [3] Pernice, et al., PNAS 101, 14007 (2004)

  3. Venus Atmospheric Maneuverable Platform (VAMP)

    NASA Astrophysics Data System (ADS)

    Griffin, K.; Sokol, D.; Lee, G.; Dailey, D.; Polidan, R.

    2013-12-01

    We have explored a possible new approach to Venus upper atmosphere exploration by applying recent Northrop Grumman (non-NASA) development programs to the challenges associated with Venus upper atmosphere science missions. Our concept is a low ballistic coefficient (<50 Pa), semi-buoyant aircraft that deploys prior to entering the Venus atmosphere, enters the Venus atmosphere without an aeroshell, and provides a long-lived (months to years), maneuverable vehicle capable of carrying science payloads to explore the Venus upper atmosphere. In 2012 we initiated a feasibility study for a semi-buoyant maneuverable vehicle that could operate in the upper atmosphere of Venus. In this presentation we report results from the ongoing study and plans for future analyses and prototyping to advance and refine the concept. We will discuss the overall mission architecture and concept of operations from launch through Venus arrival, orbit, entry, and atmospheric science operations. We will present a strawman concept of VAMP, including ballistic coefficient, planform area, percent buoyancy, inflation gas, wing span, vehicle mass, power supply, propulsion, materials considerations, structural elements, subsystems, and packaging. The interaction between the VAMP vehicle and the supporting orbiter will also be discussed. In this context, we will specifically focus upon four key factors impacting the design and performance of VAMP: 1. Feasibility of and options for the deployment of the vehicle in space 2. Entry into the Venus atmosphere, including descent profile, heat rate, total heat load, stagnation temperature, control, and entry into level flight 3. Characteristics of flight operations and performance in the Venus atmosphere: altitude range, latitude and longitude access, day/night performance, aircraft performance (aerodynamics, power required vs. power available, propulsion, speed, percent buoyancy), performance sensitivity to payload weight 4. Science payload accommodation

  4. Venus Atmospheric Maneuverable Platform (VAMP)

    NASA Astrophysics Data System (ADS)

    Polidan, R.; Lee, G.; Sokol, D.; Griffin, K.; Bolisay, L.; Barnes, N.

    2014-04-01

    Over the past years we have explored a possible new approach to Venus upper atmosphere exploration by applying recent Northrop Grumman (non-NASA) development programs to the challenges associated with Venus upper atmosphere science missions. Our concept is a low ballistic coefficient (<50 Pa), semibuoyant aircraft that deploys prior to entering the Venus atmosphere, enters the Venus atmosphere without an aeroshell, and provides a long-lived (months to years), maneuverable vehicle capable of carrying science payloads to explore the Venus upper atmosphere. VAMP targets the global Venus atmosphere between 55 and 70 km altitude and would be a platform to address VEXAG goals I.A, I.B, and I.C. We will discuss the overall mission architecture and concept of operations from launch through Venus arrival, orbit, entry, and atmospheric science operations. We will present a strawman concept of VAMP, including ballistic coefficient, planform area, percent buoyancy, inflation gas, wing span, vehicle mass, power supply, propulsion, materials considerations, structural elements, subsystems, and packaging. The interaction between the VAMP vehicle and the supporting orbiter will also be discussed. In this context, we will specifically focus upon four key factors impacting the design and performance of VAMP: 1. Science payload accommodation, constraints, and opportunities 2. Characteristics of flight operations and performance in the Venus atmosphere: altitude range, latitude and longitude access, day/night performance, aircraft performance, performance sensitivity to payload weight 3. Feasibility of and options for the deployment of the vehicle in space 4. Entry into the Venus atmosphere, including descent profile, heat rate, total heat load, stagnation temperature, control, and entry into level flight We will discuss interdependencies of the above factors and the manner in which the VAMP strawman's characteristics affect the CONOPs and the science objectives. We will show how the

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth's twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Express mission, an aerobraking campaign took the spacecraft below the ionosphere into the very weakly electrically conducting atmosphere. As the spacecraft descended from 150 to 140 km altitude, the magnetic field became weaker on average and less noisy. Below 140 km, the median field strength became steady but the short period fluctuations continued to weaken. The weakness of the fluctuations indicates they might not be useful for electromagnetic sounding of the atmosphere from a high altitude platform such as a plane or balloon, but possibly could be attempted on a lander.

  10. Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Zhang, T. L.; Baumjohann, W.; Russell, C. T.; Luhmann, J. G.; Xiao, S. D.

    2016-03-01

    The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth’s twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Express mission, an aerobraking campaign took the spacecraft below the ionosphere into the very weakly electrically conducting atmosphere. As the spacecraft descended from 150 to 140 km altitude, the magnetic field became weaker on average and less noisy. Below 140 km, the median field strength became steady but the short period fluctuations continued to weaken. The weakness of the fluctuations indicates they might not be useful for electromagnetic sounding of the atmosphere from a high altitude platform such as a plane or balloon, but possibly could be attempted on a lander.