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Sample records for venus express mission

  1. The Venus Express mission

    NASA Astrophysics Data System (ADS)

    McCoy, Donald; Siwitza, Thorsten; Gouka, Roy

    2005-11-01

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

  2. Venus Surface Investigation Using VIRTIS Onboard the ESA/Venus Express Mission

    NASA Technical Reports Server (NTRS)

    Marinangeli, L. L.; Baines, K.; Garcia, R.; Drossart, P.; Piccioni, G.; Benkhoff, J.; Helbert, J.; Langevin, Y.

    2004-01-01

    Venus Express Mission is the first ESA mission to Venus that will be launched in November 2005. In April 2006 after 150 days of cruise the spacecraft will be inserted into highly elliptical polar orbit around Venus. The observational phase will begin after about one month of commissioning phase. The nominal mission orbital life-time is two Venus sidereal days (486 Earth days). The scientific goals of Venus Express are related to the global atmospheric circulation and atmosphere chemical composition, the surfaceatmosphere physical and chemical interactions, the physics and chemistry of the cloud layer, the thermal balance and role of trace gases in the greenhouse effect, and the plasma environment and its interaction with the solar wind.

  3. 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.

  4. Post-Venus Express exploration of Venus : an in-situ mission to characterize Venus climate evolution

    NASA Astrophysics Data System (ADS)

    Chassefiere, E.; Aplin, K.; Ferencz, C.; Lopez-Moreno, J.; Leitner, J.; Marty, B.; Roos-Serote, M.; Titov, D.; Wilson, C.; Witasse, O.; Vep Team

    The planet Venus - our neighbour in the solar system and twin sister of the Earth - was once expected to be very similar to the Earth. However the space missions to the planet discovered a world completely different from ours. The fundamental mysteries in the physics of Venus are related to the composition and dynamics of the atmosphere, physics of the cloud layer and greenhouse effect, surface mineralogy, evolution of the surface and volatile inventory. Despite the fact that both Earth and Venus were formed in the same region of the solar system, the planets followed dramatically different evolutionary paths. Understanding the reasons for this divergence would shed a light on the processes of origin and evolution of all terrestrial planets including Earth. A new mission to Venus is under study. It consists of a set of probes (balloon probe, descent probes) devoted to the characterization of atmospheric chemical cycles, atmospheric electrical/ electromagnetic activity, low atmosphere dynamics, surface/ atmosphere thermo-chemical interactions, surface mineralogy and geology, with an emphasis on past climate evolution (noble gas/ isotope composition of the atmosphere). Some orbital science is planned, in complement to in-situ science. An atmosphere sample return is also considered. Information about current activity may be found at http://www.aero.jussieu.fr/VEP/, together with documents describing the present state of thoughts about scientific priorities and possible mission scenarios.

  5. Venus Express arrives

    NASA Astrophysics Data System (ADS)

    Coates, Andrew

    2006-06-01

    Venus Express uses some hardware and ideas already in use on Mars Express and Rosetta to explore Venus, a planet with intriguing similarities to and differences from Earth. As the mission proper begins, I examine what we have learnt from other missions and what we hope to discover at Venus. Instruments on the mission will look at the thick atmosphere of Venus below its sulphuric acid clouds and how it interacts with the surface and escapes to space. They will also try to understand the runaway greenhouse effect and search for active volcanism.

  6. 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.

  7. 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…

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. Venus Express Italian Day on 4 October

    NASA Astrophysics Data System (ADS)

    2004-09-01

    Venus Express is the first European mission to this, the second planet in the Solar System. Often referred to as ‘Earth’s twin’, Venus holds many mysteries that intrigue scientists. The main question is why a planet similar to Earth in size, mass and composition could have evolved so differently over the course of the last four thousand million years. Venus Express will make the first multispectral global examination of the atmosphere of Venus. Completely different from the one around Earth, the Venusian atmosphere appears to be hot and dense. Venus Express will investigate the choking ‘greenhouse’ effect, the hurricane-force winds that encircle the planet, and its mysteriously weak magnetic field. Completion of assembly of the Venus Express spacecraft, including integration and testing of the flight equipment and experiments, is an important milestone. Scheduled for launch on 26 October 2005, Venus Express is currently being made ready for shipment to Astrium, ESA’s prime contractor, in Toulouse, France in mid-October this year. There, further tests to prove the spacecraft's flight readiness will take place. The programme of the event is as follows: 10:30 - Welcoming addresses L.M. Quaglino, Director of Alenia Spazio Infrastructures and Scientific Satellites M. Coradini, ESA Solar System Missions Coordinator 10:45 - ESA presentations The Venus Express project, D. McCoy, ESA Project Manager for Venus Express The Scientific Mission, H. Svedhem, ESA Project Scientist for Venus Express 11:30 - Alenia Spazio: Role and activities on Venus Express G. Finocchiaro and M. Patroncini, Alenia Spazio Project Management for Venus Express The presentations will be followed by a visit to the Venus Express Hardware and a Q & A session. The programme will be concluded with a buffet lunch at 13:00.

  13. Education and Public Outreach using Venus Express

    NASA Astrophysics Data System (ADS)

    Pertzborn, Rosalyn A.; Limaye, S. S.; Pi, H. Y.

    2006-12-01

    Nearly two decades after NASA’s Magellan radar mission to Venus, its atmosphere and surface is being investigated with new instruments by the Venus Express spacecraft from orbit. It was launched by the European Space Agency (ESA) on 11 November 2005, and has been orbiting Venus since April 2006. This mission provides an opportunity to focus on comparative planetary meteorology for education and public outreach efforts. We present an inquiry-based approach for informal and formal learning audiences by comparing atmospheric states of Venus and Earth using data available from Earth weather satellites and Venus Express. In the context of a middle or a high school curriculum, the science themes of Venus Express mission provide many connections to the themes of the National Science Education Standards. For the general audiences, Venus presents many of its mysteries such as its super rotation in the form of a giant hemispheric vortex akin to a hurricane, its deep atmosphere with sulfuric acid clouds, and the huge greenhouse effect concepts that are familiar to many. More than a dozen US scientists are participating in the Venus Express mission with support from NASA.

  14. Post-Venus Express exploration of Venus : the Venus Entry Probe Initiative

    NASA Astrophysics Data System (ADS)

    Chassefière, E.; Roos-Serote, M.; Titov, D.; Wilson, C.; Witasse, O.; Vepi Team

    The planet Venus -- our neighbour in the solar system and twin sister of the Earth -was once expected to be very similar to the Earth However the space missions to the planet discovered a world completely different from ours The fundamental mysteries in the physics of Venus are related to the composition and dynamics of the atmosphere physics of the cloud layer and greenhouse effect surface mineralogy evolution of the surface and volatile inventory Despite the fact that both Earth and Venus were formed in the same region of the solar system the planets followed dramatically different evolutionary paths Understanding the reasons for this divergence would shed a light on the processes of origin and evolution of all terrestrial planets including Earth Early missions to Venus in 1960-90 included a great variety of robotic spacecraft fly-bys orbiters landers and balloons They established basic understanding of the conditions prevailing in the atmosphere and on the surface of Venus In the same time they raised a number of fundamental questions concerning the mechanisms and processes that formed and are maintaining these conditions The new era of Venus exploration began with the launch of the ESA Venus Express spacecraft in November 2005 The spacecraft will deliver a powerful suite of remote sensing instruments into orbit around the planet The mission will perform a global survey of the Venus atmosphere and plasma environment The Japanese Planet-C mission scheduled for launch in 2010 will focus on meteorological monitoring from orbit These

  15. The MESSENGER Venus Flybys: Opportunities for Synergy with Venus Express

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.; McNutt, R. L.; Domingue, D. L.; Gold, R. E.; Svedhem, H.; Titov, D.; Helbert, J.

    2006-12-01

    The trajectory of the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft, launched by NASA on 3 August 2004 and destined to be the first probe to orbit Mercury, includes two flybys of Venus during the period that the ESA Venus Express mission is operational in Venus orbit. MESSENGER's first Venus flyby occurred on 24 October 2006, at a closest approach distance of 3140 km, but no scientific observations were made because Venus was at superior conjunction and no direct communication with the MESSENGER spacecraft (or with Venus Express) was possible for an extended period. All MESSENGER instruments, however, will be trained on Venus during the spacecraft's second flyby on 6 June 2007, when closest approach will be at 300 km altitude over 12°S, 107°E, in the uplands of Ovda Regio. The Mercury Dual Imaging System will image the night side in near-infrared bands, and color and higher-resolution monochrome mosaics will be made of both the approaching and departing hemispheres. The Ultraviolet and Visible Spectrometer on the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) instrument will make profiles of atmospheric species on the day and night sides as well as observations of the exospheric tail on departure. The Visible and Infrared Spectrograph on MASCS will observe the planet near closest approach to sense cloud chemical properties and near-infrared returns from the lower atmosphere and surface. The laser altimeter will serve as a passive 1064-nm radiometer and will measure the range to one or more cloud decks for several minutes near closest approach. The combined observations of Venus Express and MESSENGER will permit simultaneous and complementary observations of particular value for characterization of the particle and field environment at Venus. MESSENGER's Energetic Particle and Plasma Spectrometer (EPPS) will observe charged particle acceleration at the Venus bow shock and elsewhere. The Magnetometer will

  16. 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/

  17. Venus Express and terrestrial planet climatology

    NASA Astrophysics Data System (ADS)

    Taylor, Fredric W.; Svedhem, Håkan; Titov, Dmitri M.

    After a delay of more than a decade, the exploration of Venus has resumed through the European Venus Express mission, now in orbit around the planet. The mission payload, its implementation in an elliptical polar orbit, and the science operations planned, all focus on outstanding problems associated with the atmosphere and climate of Venus. Many of these problems, such as understanding the extreme surface warming produced by the carbon dioxide-driven greenhouse effect, and the role of sulfate aerosols in the atmosphere, have resonances with climate-change issues on the Earth and Mars. As data on all three terrestrial planets accumulates, and models of the energy balance and general circulation of their atmospheres improve, it becomes increasingly possible to define and elucidate their behavior in a common, comparative framework. Venus Express seeks to contribute to progress in this area.

  18. 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

  19. PLANET-C: Venus Climate Orbiter Mission of Japan

    NASA Astrophysics Data System (ADS)

    Ueno, M.; Nakamura, M.; Imamura, T.; Iwagami, N.; Satoh, T.; Watanabe, S.; Taguchi, M.; Takahashi, Y.; Suzuki, M.; Yamada, M.; Hashimoto, G.; Kasaba, Y.; Fukuhara, T.; Uemizu, K.; Abe, T.; Ishii, N.; Oyama, K.

    2006-08-01

    Venus is one of the most attractive targets in the solar system when we seek to understand the formation of the terrestrial environment. Venus is our nearest neighbor, and has a size very similar to the Earth's; however, previous spacecraft missions discovered an extremely dense (~90 bar) and dry CO[2] atmosphere with H[2]SO[4]-H[2]O clouds floating at high altitudes, and exotic volcanic features covering the whole planet. The abundant gaseous CO[2] brings about a high atmospheric temperature (~740 K) near the surface via greenhouse effect. The atmospheric circulation is also much different from the Earth's. The mechanisms which sustain such conditions are unclear and considered to be the keys to understand the origin of the terrestrial environment. In spite of the many previous missions that explored Venus, such as the Venera, Pioneer Venus, Vega and Magellan, most of the fundamental questions raised so far still remain unsolved. The Venus Climate Orbiter mission (PLANET-C), one of the future planetary missions of Japan, aims at understanding the atmospheric circulation of Venus. Meteorological data will be obtained by globally mapping clouds and minor constituents successively with 4 cameras at ultraviolet and infrared wavelengths, detecting lightning with a high-speed imager, and observing vertical structures of the atmosphere with radio science technique. The equatorial elongated orbit with westward revolution fits the observations of the movement and temporal variation of the Venusian atmosphere which rotates westward. The systematic, continuous imaging observations will provide us with an unprecedented large dataset of the Venusian meteorology. Additional targets of the mission are the exploration of the ground surface and the observation of zodiacal light. The mission will complement the ESA's Venus Express, which also explores the Venusian environment with different approaches. The spacecraft will be launched and arrive at Venus in 2010, and will perform 2

  20. Future Venus Exploration: Mission Venera-D

    NASA Astrophysics Data System (ADS)

    Zasova, L. V.; Ignatiev, N. I.; Gerasimov, M. V.

    2014-05-01

    Venera-D is a strategic mission to explore Venus, included in the Russian Federal Space Program 2016-2025. Venera-D mission is in the phase A now. The Venera-D Roscosmos/IKI - NASA Joint Science Definition Team has been formed in February 2014.

  1. Thermal structure of Venus atmosphere from Venus Express observations

    NASA Astrophysics Data System (ADS)

    Bertaux, J. L.; Drossart, P.; Grassi, D.; Häusler, B.; Mahieux, A.; Migliorini, A.; Montmessin, F.; Pätzold, M.; Piccialli, A.; Piccioni, G.; Tellmann, S.; Vandaele, A. C.; Wilquet, V.

    2014-04-01

    The thermal structure of Venus atmosphere has been investigated since the early 1960s by several groundbased campaigns and spacecraft missions, such as Pioneer Venus (PV) orbiter [1], PV probes [2], Galileo flyby [3], Venera 15 and 16 [4]. Based on these early and sparse observations, a Venus International Reference Atmosphere (VIRA) model was published in 1983 [5]. The VIRA model splits the atmosphere into three different dynamical regions: (1) the lower atmosphere, from the surface to the upper cloud top (˜ 70 km), (2) the middle atmosphere, extending between the cloud tops and 110 km, and (3) the upper atmosphere, above ~110 km. Vertical temperature profiles below 40 km of altitude are quite similar over the entire planet, with latitudinal and local time variations less than 5 K. On the other hand, the thermal structure of the middle and upper atmosphere shows a significant variability with latitude and local time. The VIRA model presents an atmosphere temperature that decreases from values of ˜ 240 K at the cloud top to 170 K at ˜ 90 - 100 km altitudes on the dayside of the planet and reaching minimum values of less than 120 K during the nighttime in the upper atmosphere[5]. More recently, several experiments on board the European mission to Venus, Venus Express (VEx) [6], and ground-based campaigns [7,8,9] have extensively studied the thermal structure of Venus upper atmosphere over a long time scale revealing a far more complex situation. Three different methods are used to sound remotely atmospheric temperatures: (1) the VeRa radio occultation instrument studies the upper troposphere/mesosphere (40 - 90 km) of both the north and south hemispheres with a vertical resolution of ~500 m [10,11]; (2) the nightside mesosphere (60 - 90 km) is investigated also by VIRTIS thermal emission spectroscopy [12,13]; (3) finally, SPICAV-SOIR stellar/solar occultations sound Venus upper atmosphere (70 - 150 km altitude) on the nightside and at the terminator [14

  2. 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.

  3. The Magellan Venus radar mapping mission

    NASA Astrophysics Data System (ADS)

    Saunders, R. S.; Pettengill, G. H.; Arvidson, R. E.; Sjogren, W. L.; Johnson, W. T. K.; Pieri, L.

    1990-06-01

    The NASA Magellan Venus Radar Mapper spacecraft, which will be placed into orbit around Venus on August 10, 1990, is described and its mission is discussed. The orbiter's 12-cm wavelength, multimode radar system is examined and the applications of its modes are addressed. In the SAR mode, it can image most of the Venus surface at a resolution of better than 300 m, approaching 120 m over more than half the planet. In the altimeter mode, the radar will determine topographic relief to a vertical accuracy of better than 50 m averaged over a surface resolution cell approximately 10 km in diameter. In the radiometer mode, the radar receiver can determine the surface radio emission brightness temperature with an absolute accuracy of 20 K, at a resolution of 2 K. The nature of the data products and the archiving plans are also considered.

  4. 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

  5. Experimental Aerobraking with Venus Express

    NASA Astrophysics Data System (ADS)

    Svedhem, Hakan

    2013-10-01

    Venus Express has successfully orbited Venus in its polar 24 hour, 250km by 66000 km, orbit since April 2006 and has provided a wealth of new data from our sister planet. Approaching the end of the mission we are now planning an experimental campaign dedicated to aerobraking at altitudes down to as low as about 130km. These low pericentre passes will provide direct measurements of density, temperature, magnetic field and energetic particles in a region not accessible by other methods. Experience of operations and studies of spacecraft responses will be valuable knowledge for possible future missions that might need this techniques as a part of its nominal operations. Aerobraking was considered in the early design phase of the mission but it was fairly soon realised that the nominal mission would not need this. However, a few important design features were maintained in order to allow for this in case it should be needed at a later stage. The inherently stable geometry of the spacecraft configuration and the inclusion of a software mode for aerobraking are the two most important elements from this early design phase. An recent study by industry has determined the constraints for the spacecraft and identified several potential scenarios. The present highly elliptical orbit has as one of its inherent features a downward drift of the pericentre altitude of between 1 and 4 km/day. However, at certain times, when the Sun is in the orbital plane, this drift disappears for a period of up to two weeks. This is a very well suited time to carry out these initial experiments as it is makes operations safer and it reduces the heat input on the spacecraft as the solar panels will be edge-on towards the sun during the aerobraking. Already a number of low altitude operations have been carried out during the so called atmospheric drag campaigns. The spacecraft has then dipped down to altitudes as low as 165 km and a good characterisation of this region has been performed. This

  6. 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

  7. 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

  8. Observing the surface of Venus with VIRTIS on Venus Express

    NASA Astrophysics Data System (ADS)

    Helbert, J.; Mariangeli, L.; Baines, K. H.; Garcia, R.; Erard, S.; Piccioni, G.; Drossart, P.; Müller, N.; Hashimoto, G.; Kostama, P.; Virtis Team

    The M channel of VIRTIS will allow the first systematic mapping of the surface and of the near-surface atmosphere of Venus in the near infrared wavelengths range This will be done using the atmospheric windows located at 1 10 1 18 mu m and if possible additionally using the window at 1 02 mu m Wattson and Rothman 1986 Kamp et al 1988 Moroz 2002 The latter is unfortunately right at the low end of the wavelength range of the IR channel and at the upper end of the VIS channel Therefore the usability of this window is unclear until first data from Venus are obtained The atmospheric windows will allow measuring the thermal emission of the surface as was demonstrated by Galileo NIMS Carlson et al 1991 and Cassini VIMS Baines et al 2000 While the atmospheric windows show no or little CO 2 absorption the radiance from the surface is still affected by scattering in the clouds This effect varies based on the optical thickness of the clouds We have developed a quicklook processing procedure which allows deriving surface emissivity variations from nighttime observations correcting for the atmospheric effects We will present the first version of this algorithm During the mission the algorithm will be refined based on the data returned from the different instruments on Venus Express The final goal is to derive maps of the absolute surface emissivity Based on these data two main science tasks for the surface analysis will be pursued Classification of the surface composition and study the interaction between low atmosphere and

  9. Venus

    NASA Technical Reports Server (NTRS)

    Hunten, D. M. (Editor); Colin, L. (Editor); Donahue, T. M. (Editor); Moroz, V. I.

    1983-01-01

    The present conference concerning the study of Venus discusses stellar magnitude and albedo data for the planet, radio astronomical studies, results of the Venera 13 and 14 missions, Venus optical properties, topography, surface properties and tectonic evolution, the tectonic implications of the interior of Venus, the thermal structure, photochemistry, composition, general circulation, and electrical activity of the Venus atmosphere, and the thermal balance of the lower, middle and upper atmoshere of Venus. Also discussed are the observation and interpretation of the Venus ionosphere, its model calculation, the interaction of the solar wind with the ionosphere of Venus in light of flow field models, the origin and evolution of the Venus atmosphere, and the problem posed by rare gases in the atmosphere of Venus.

  10. 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

  11. Altimeter and radiometer for a Venus orbiter mission

    NASA Technical Reports Server (NTRS)

    Bryan, J. W.; Richter, K. R.

    1971-01-01

    The concept, constraints, and capabilities of a radar altimeter type contour mapper for a Venus orbiter mission are presented. The system was developed for the proposed planetary explorer universal bus concept. A system with a height precision of 30meters over a surface area of 7200 square kilometers is achieved. Using this system and the orbit proposed in the orbiting bus concept, the northern hemisphere of Venus is mapped in one Venus day. The radar receiver system, is used in a radiometer mode to obtain a map of the diurnal and logitudinal variations of the Venus surface temperature with a resolution of 3.0 degrees Kelvin.

  12. 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

  13. Characterizing the low-altitude magnetic belt at Venus: Complementary observations from the Pioneer Venus Orbiter and Venus Express

    NASA Astrophysics Data System (ADS)

    Villarreal, M. N.; Russell, C. T.; Wei, H. Y.; Ma, Y. J.; Luhmann, J. G.; Strangeway, R. J.; Zhang, T. L.

    2015-03-01

    Using Venus Express, Zhang et al. (2012b) identified strong magnetic field enhancements at low altitudes over the north polar region of Venus as giant flux ropes. Strong fields at low altitudes were also observed during the Pioneer Venus Orbiter mission, but at low latitudes near the subsolar and midnight regions. We examine the possibility that the Venus Express observations are not giant flux ropes, but part of a low-altitude magnetic belt that builds up in the subsolar region, passes over the terminator, and extends to the nightside. Our analysis indicates the magnetic belt is dominantly horizontal over the dayside and gains a radial component nightward. The peak magnetic field strength of the belt and the altitude at which it peaks also varies around the planet, with the lowest altitude and strongest field strength in the subsolar region, consistent with the idea of the belt forming on the dayside. Zhang et al. (2012b) also noted the fields in the polar region had a bias in the +By direction in Venus Solar Orbital coordinates. The multifluid magnetohydrodynamic simulation we present shows an asymmetry in the plasma flow from the subsolar region to the poles due to the oxygen ion and proton mass ratio. This causes the magnetic field to preferentially accumulate in the north for a +By interplanetary magnetic field direction, providing an explanation for this bias.

  14. 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.

  15. 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.

  16. 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

  17. 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)

  18. 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.

  19. 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.

  20. Combustion-based power source for Venus surface missions

    NASA Astrophysics Data System (ADS)

    Miller, Timothy F.; Paul, Michael V.; Oleson, Steven R.

    2016-10-01

    The National Research Council has identified in situ exploration of Venus as an important mission for the coming decade of NASA's exploration of our solar system (Squyers, 2013 [1]). Heavy cloud cover makes the use of solar photovoltaics extremely problematic for power generation for Venus surface missions. In this paper, we propose a class of planetary exploration missions (for use on Venus and elsewhere) in solar-deprived situations where photovoltaics cannot be used, batteries do not provide sufficient specific energy and mission duration, and nuclear systems may be too costly or complex to justify or simply unavailable. Metal-fueled, combustion-based powerplants have been demonstrated for application in the terrestrial undersea environment. Modified or extended versions of the undersea-based systems may be appropriate for these sunless missions. We describe systems carrying lithium fuel and sulfur-hexafluoride oxidizer that have the potential for many days of operation in the sunless craters of the moon. On Venus a system level specific energy of 240 to 370 We-hr/kg should be possible if the oxidizer is brought from earth. By using either lithium or a magnesium-based alloy fuel, it may be possible to operate a similar system with CO2 derived directly from the Venus atmosphere, thus providing an estimated system specific energy of 1100 We+PV-hr/kg (the subscript refers to both electrical and mechanical power), thereby providing mission durations that enable useful scientific investigation. The results of an analysis performed by the NASA Glenn COMPASS team describe a mission operating at 2.3 kWe+PV for 5 days (120 h), with less than 260 kg power/energy system mass total. This lander would be of a size and cost suitable for a New Frontiers class of mission.

  1. 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.

  2. The Venus Neutral Atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    The Venus Express Radio Science Experiment VeRa is sounding the Venus neutral atmosphere and ionosphere using the spacecraft radio subsystem in the oneway radio link mode at X-band (8.4 GHz) and S- band (2.3 GHz). An Ultrastable Oscillator (USO) provides a high quality onboard frequency reference source for the derivation of electron density profiles in the ionosphere and profiles of pressure, temperature and neutral number density of the neutral atmosphere. Radial profiles of neutral number density derived from the occultations cover the altitude range 40 to 90 km, which are converted to vertical profiles of temperature and pressure. The polar orbit of Venus Express provides the opportunity to study the atmosphere at all planetocentric latitudes under varying illumination conditions. Five occultation seasons could be covered so far during the Venus Express mission resulting in a data set of more than 150 profiles of the neutral atmosphere. The thermal structure is investigated with regard to the latitudinal and temporal variability. A distinct cold collar region could be observed on both hemispheres. The tropopause altitude increases in this latitude region while the tropopause temperature shows a strong decrease. Profiles of static stability are found to be latitude-dependent and nearly adiabatic in the middle cloud region.

  3. 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.

  4. Improved calibration of SOIR/Venus Express spectra.

    PubMed

    Vandaele, Ann Carine; Mahieux, Arnaud; Robert, Séverine; Berkenbosch, Sophie; Clairquin, Roland; Drummond, Rachel; Letocart, Vincent; Neefs, Eddy; Ristic, Bojan; Wilquet, Valérie; Colomer, Frédéric; Belyaev, Denis; Bertaux, Jean-Loup

    2013-09-01

    The SOIR instrument on board the ESA Venus Express mission has been operational since the insertion of the satellite around Venus in April 2006. Since then, it has delivered high quality IR solar occultation spectra of the atmosphere of Venus. The different steps from raw spectra to archived data are described and explained in detail here. These consist of corrections for the dark current and for the non-linearity of the detector; removing bad pixels, as well as deriving noise. The spectral calibration procedure is described, along with all ancillary data necessary for the understanding and interpretation of the SOIR data. These include the full characterization of the AOTF filter, one of the major elements of the instrument. All these data can be found in the ESA PSA archive.

  5. 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

  6. The Venus Neutral Atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, Silvia; Haeusler, Bernd; Paetzold, Martin; Bird, Michael; Tyler, G. L.; Andert, Thomas; Remus, Stefan

    The Venus Express Radio Science Experiment VeRa performs regular radio-sounding experi-ments in the Venus neutral atmosphere and ionosphere using the spacecraft radio subsystem in the one-way radio mode at X-band (8.4 GHz) and S-band (2.3 GHz). An Ultra-Stable Oscilla-tor (USO) provides a high quality on-board frequency reference for refractivity measurements, from which electron density profiles in the ionosphere and profiles of pressure, temperature and neutral number density of the neutral atmosphere are derived. Radial profiles of neutral number density from the atmospheric-induced Doppler shift during the occultations cover the altitude range 40-90 km. These are then used to derive vertical profiles of temperature and pressure. The polar orbit of Venus Express provides the opportunity to study the troposphere and meso-sphere at all planetocentric latitudes under varying illumination conditions. Seven occultation seasons have occurred thus far during the Venus Express mission, resulting in a data set with more than 320 neutral atmospheric profiles. The thermal structure is investigated with regard to the latitudinal and temporal variability. The Venus mesosphere shows a high variability resulting from atmospheric waves and turbulence. Profiles of atmospheric static stability are found to be latitude dependent and nearly adiabatic in the middle cloud region. Abrupt changes in the static stability can occur at the boundaries of the middle cloud layer, the vertical dis-tribution of which shows a distinct latitudinal dependence. Correlations of wave activity with the static stability profile will be investigated

  7. 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

  8. Venus Express/VMC observations of the Venus O2 visible nightglow

    NASA Astrophysics Data System (ADS)

    García Muñoz, Antonio; Hueso, Ricardo; Sanchez-Lavega, Agustin; Markiewicz, Wojciech; Opitz, Andrea; Witasse, Olivier; Titov, Dmitrij

    2013-04-01

    We are analyzing the images of the Venus night side obtained with the Venus Monitoring Camera (VMC) aboard Venus Express at visible wavelengths (passband of 502-568 nm at 1/4 maximum transmission). The images show a faint but distinct emitting layer at about 100 km altitude attributed to the O2 visible nightglow discovered by the Venera 9/10 missions [1]. The visible filter is most sensitive to the v''=9, 10 bands of the c(0)-X(v'') progression, that occur at 513 and 551 nm, respectively. The VMC images allow us to investigate day-to-day variations in the nightglow intensity, that typically ranges from 200 to 400 kiloRayleighs in limb viewing, over the Venus disk, thus expanding on past studies from either space-borne or ground-based telescopes. In the presentation, we will discuss the status of our analysis of nearly five years of O2 visible nightglow data with VMC. Ref.: [1] Krasnospolsky et al. (1977), Cosmic Res., 14, 687.

  9. 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.

  10. Upstream proton cyclotron waves at Venus observed by Venus Express magnetometer

    NASA Astrophysics Data System (ADS)

    Delva, Magda; Volwerk, Martin; Bertucci, Cesar; Mazelle, Christian; Romanelli, Norberto; Voeroes, Zoltan

    2016-07-01

    An overview of the observations of proton cyclotron waves (PCWs) upstream of the Venus bow shock from the magnetometer data on Venus Express is given. The first detection of this specific type of upstream waves proved that newborn planetary ions from the upper exosphere are directly picked up by the instreaming solar wind. Their occurrence up to large distances (~ 9 Rv) from the planet raises the question of the existence of an extended reservoir of planetary neutral hydrogen. Also, the loss of exospheric hydrogen directly to the solar wind has implications for the evolution of the planetary atmosphere over the age of the solar system. The successful long duration of the Venus Express mission allows to study the occurrence of PCWs under solar minimum and solar maximum conditions. Results of long term studies for both cases are presented and compared. Explanations for the differences are found in the unusual nature of the current solar maximum, which was characterized by low sunspot numbers, low density and mainly moderate speed.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Venus Terminator Temperature Structure: Venus Express SOIR and VTGCM Comparisons

    NASA Astrophysics Data System (ADS)

    Schulte, R.; Bougher, S. W.; Parkinson, C. D.; Brecht, A. S.; Vandaele, A.; Wilquet, V.; Mahieux, A.

    2013-12-01

    Venus Express SOIR terminator profiles of temperatures are organized and presented for 119 selected orbits obtained between 2006-2011. The SOIR instrument measures CO2 absorption across a broad spectral window. The observed atmospheric transmittance spectra are subsequently inverted to obtain vertical CO2 density (and inferred temperature) profiles at the Venusian terminator over approximately 70 to 160 km. These recently recalibrated measurements continue to show a striking permanent temperature minimum (at 125 km) and a weaker temperature maximum (over 100-115 km). These features are reflected in the corresponding CO2 density profiles, and provide detailed constraints for new empirical models and global circulation models of the Venus upper atmosphere. New Venus Thermospheric General Circulation Model (VTGCM) simulations are conducted for conditions appropriate to these SOIR measurements. In particular, solar minimum or moderate fluxes are specified and mean values of eddy diffusion and wave drag parameters are utilized. Recent upgrades to the VTGCM code now include more realistic lower boundary conditions at 70 km near cloud tops. Model temperature profiles are extracted from the terminators that correspond to five latitude bins (0-30°, 30-60°, 60-70°, 70-80°, 80-90° latitude) presently used in the SOIR data analysis. Averaging of VTGCM temperature profiles in each of these bins (at morning and evening terminators) is conducted to match SOIR sampling. Comparisons of these SOIR and VTGCM temperature profiles are made. Most notably, the observed temperature minimum near 125 km and the weaker temperature maximum over 100-115 km are generally reproduced by the VTGCM at the correct pressure/altitude levels. However, magnitudes of simulated and measured temperatures are somewhat different. In addition, VTGCM evening terminator (ET) temperatures are simulated to be modestly warmer than corresponding morning terminator (MT) values, a result of stronger ET than MT

  16. Venus surface investigation based on VIRTIS measurements on Venus Express

    NASA Astrophysics Data System (ADS)

    Arnold, Gabriele; Haus, Rainer; Döhler, Wolfgang; Kappel, David; Piccioni, Giuseppe; Drossart, Pierre

    The dense atmosphere of Venus prevented systematic studies of its surface at optical wavelengths in the past. The discovery of near infrared nightside atmospheric windows has opened a new challenge for detailed surface studies. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express is the first experiment collecting continuously nightside surface emission data from the planet. The observed high variability of measured signatures is mainly due to spatial variations of cloud optical depth and surface elevation. The investigation of surface properties requires a convergent approach of radiative transfer simulations and VIR- TIS data analyses. Therefore, a selection of orbits with well calibrated data over the northern hemisphere was performed for footprints that cover a maximum range of surface elevation variations. Radiative transfer calculations demonstrate that the conservative character of cloud multiple scattering below 2 µm and a strong dependence of radiance ratios on surface elevation in this spectral region allow the mapping of surface topography and a retrieval of the surface temperature. To the first order, the surface temperature is a function of ground elevation. Small deviations from this first order dependence have been identified that are possibly due to different surface materials. 1 Institut f¨r Planetologie, Westf¨lische Wilhelms-Universit¨t M¨nster, Wilhelm-Klemm-Str.10, u a a u 48129 M¨nster, Germany u 2 German PlaceNameAerospace PlaceTypeCenter (DLR), Remote Sensing Technology Institute, Dpt. Marine Remote Sensing, Rutherfordstrasse 2, 12489 CityplaceBerlin, countryregionGermany 3 German PlaceNameAerospace PlaceTypeCenter (DLR), Institute for Planetary Research, Rutherfordstrasse 2, 12489 CityplaceBerlin, country-regionGermany 4 LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, e 92195 Meudon, France 5 INAF-IASF (Instituto di Astrofisica Spaziale e Fisica Cosmica), via

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    1988-06-01

    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.

  19. The structure of the Venus neutral atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, Silvia; Bird, Mike; Verweyen, Alice; Haeusler, Bernd; Paetzold, Martin; Tyler, G. L.

    The Venus Express Radio Science Experiment VeRa uses one-way radio signals at X-band and S-band for the sounding of the Venus neutral atmosphere and ionosphere. An Ultrastable Oscillator (USO) provides a high quality onboard frequency reference source for this one-way radio link. Simultaneous, coherent measurements at two wavelengths allow separation of dispersive media effects from the classical Doppler shift. Electron density profiles of the ionosphere and profiles of pressure, temperature and neutral number density of the neutral atmosphere can be derived via an Abel transform with an altitude resolution of only a few hundred metres in the altitude range between about 40 and 100 km. Three occultation seasons could be covered during the nominal mission of Venus Express resulting in a data set of about 140 profiles of the neutral atmosphere. Another three occultation seasons are planned during the extended mission. The polar orbit of Venus Express provides the opportunity to study the atmosphere at all planetocentric latitudes under varying illumination conditions. Day-night and latitudinal variations of the thermal structure, the high variability of the atmosphere above the troposphere and signal absorption effects caused by the H2SO4 vapour can be investigated with the resulting data set.

  20. Venus Express Contributions to the Study of Planetary Lightning

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  1. Venus O2 nightglow observations with VIRTIS/Venus Express

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Piccioni, G.; Gérard, J. C.; Slanger, T.; Politi, R.; Snels, M.; Nuccilli, F.; Drossart, P.

    2012-09-01

    The oxygen nightglow emissions in the visible spectral range are known since the early observations with the Venera spacecrafts. Recent observations with the VIRTIS instrument on board Venus-Express allowed to re-detect the Herzberg II system of O2. In particular, the (0-7), (0-8), (0-9), (0-10), and (0-11) bands of the Herzberg II system have been observed in the limb data. These bands peak at about 95 km, with a mean total integrated intensity of about 200 kR. Moreover, 3 bands of the Chamberlain system, centred at 0.56 μm, 0.605 μm, and 0.657 μm were also detected. For the first time, the O2 nightglow emissions were investigated simultaneously in the visible and in the IR spectral range, reporting a good agreement of the peak altitude values for the Herzberg II and the O2(a1Δg-X3Σ- g) band. Finally a 1-D atmospheric model was applied in order to interpret our results. The model, starting from realistic O and CO2 vertical distribution, allows to well reproduce the observed profiles for the O2 systems both in the visible and IR spectral ranges.

  2. Climate change on Venus and future spacecraft mission priorities

    NASA Astrophysics Data System (ADS)

    Bullock, M.; Grinspoon, D.

    Weathering of surface minerals in the sulfur-rich lower atmosphere of Venus may well have played a significant role in the recent evolution of the planet's climate. SO 2 in the atmosphere is interesting because it is the primary precursor of Venus' bright H 2SO 4 /H 2O clouds, it is a greenhouse gas, it is most likely outgassed by volcanoes [Prinn, 1985], it probably reacts with the surface, and it is apparently much higher in abundance that would be expected from thermochemical equilibrium with the surface [Fegley and Treiman, 1992] (although interpretations of Vega 1 and 2 UV spectrometer data challenge the latter, see Bertaux et al., [1996]). Changes in the atmospheric abundance of SO 2 would be accompanied by alterations in the optical properties of the clouds and in the greenhouse effect, thereby affecting surface temperatures [Bullock and Grinspoon, 2001]. Fegley and Prinn , [1989] demonstrated e perimentally that the reaction CaCO3 +x SO 2 ==> CaSO 4 + CO proceeds rapidly under Venus-like conditions, and concluded that SO 2 and hence the H 2 SO 4 /H 2O clouds would disappear in 1.9 My unless SO 2 in the atmosphere were continually replenished by volcanic outgassing. Using a coupled chemical kinetic reaction-diffusion and climate model, [ Bullock and Grinspoon, 2001] calculated that volcanism must supply SO 2 to the atmosphere on approximately 30 My timescales in order to maintain clouds with their current optical properties. Clues to the nature of the recent Venus climate may be obtained by elucidating the sensitivity of cloud properties to changes in a mospheric SO 2 andt H 2O and by investigations into the styles and depths of chemical weathering at the surface. Future robotic spacecraft missions have the pot ential to provide significant insights into recent climate change on Venus and on the role that sulfur may have played. Among the most important and scientifically valuable investigations are: 1. High spectral, spatial, and temporal resolution near

  3. 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

  4. 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.

  5. 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,

  6. 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

  7. The Structure of the Venus Neutral Atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, S. A.; Häusler, B.; Pätzold, M.; Bird, M. K.; Tyler, G. L.

    2007-12-01

    The Venus Express Radio Science Experiment VeRa is sounding the Venus neutral atmosphere and ionosphere using the spacecraft radio subsystem in the oneway radio link mode. An Ultrastable Oscillator (USO) provides a high quality onboard frequency reference source for the derivation of electron density profiles in the ionosphere and profiles of pressure, temperature and neutral number density of the neutral atmosphere. The measurement configuration allows an altitude resolution of only a few hundred metres from the cloud deck at about 40 km to approximately 100 km. Three occultation seasons could be covered in the first two years of the Venus Express mission resulting in a data set of about 140 profiles of the neutral atmosphere. The polar orbit of Venus Express provides the opportunity to study the atmosphere at all planetocentric latitudes under varying illumination conditions. Special attention will be given to day-night variations of the thermal structure and the temperature distribution at high polar latitudes on both hemispheres ("cold collar region") and signal absorption effects caused by the H2SO4 vapour.

  8. The Venus visible oxygen nightglow with VIRTIS on board Venus Express

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Piccioni, G.; Gérard, J.-C.; Drossart, P.

    2011-10-01

    The oxygen nightglow emissions in the visible spectral range have been known since the early observations with the Venera spacecraft. The more recent observations with the VIRTIS (Visible and InfraRed Thermal Imaging Spectrometer) instrument on board the ESA mission Venus Express, allow a detailed study of the Herzberg II system of O2, reporting a maximum value of 200 kR for the integrated intensity of the progression. The (0-7), (0- 8), (0-9), (0-10) and the (0-11) bands of the Herzberg II system have been identified in the limb geometry observation data. In this work, we present results about the vertical profile of the observed bands, as well as the total integrated intensity of each single band.

  9. The Magnetic Field in the Lower Ionosphere of Venus as Seen by Venus Express

    NASA Astrophysics Data System (ADS)

    Villarreal, Michaela; Russell, Christopher T.; Zhang, Tielong

    2016-10-01

    In June 2014, the Venus Express mission conducted its aerobraking campaign that allowed the spacecraft to get to its lowest altitude of 130 km. This provided the first measurements of the lower ionosphere over the north polar region. The data show below ~140 km the magnetic field becomes relatively constant in magnitude and direction. Over the month long aerobraking period, the magnetic field in the lower ionosphere is dominantly horizontal and shows a distinct bias in the +Bx and –By direction despite the field direction at higher altitudes. Here we analyze the relationship between the direction of the lower ionosphere and the long-term average of the interplanetary magnetic field direction.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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)

  17. Ionospheric Modulation of Venus Express Lightning Detection Rates

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  18. 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.

  19. Newest results from SPICAV on-board Venus Express

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    Venus Express is now entering its eighth year of operation in Venusian orbit. Among the still working instruments, all three channels of the SPICAV [Bertaux et al., 2007] spectrometer are still fully working and routinely provide new insights on the Venusian atmosphere. We propose to review and highlight the results and the work in progress, among which (non-exhaustive list): a new mapping of the nightside airglow of nitric oxide (NO) using the nadir mode of SPICAV-UV ; the first detection of the dayglow due to CO and CO2+ using limb observations of SPICAV-UV [Chaufray et al., 2012] ; the secular evolution of SO2 column density above Venus' cloud top using SPICAV-UV in nadir mode [Marcq et al., 2013] ; polarimetric and phase function studies of the upper clouds of Venus using SPICAV-IR. Bibilography: Bertaux et al., SPICAV on Venus Express: Three spectrometers to study the global structure and composition of the Venus atmosphere, PSS (2007) Chaufray et al., First observation of the Venus UV dayglow at limb from SPICAV/VEX, Geophys. Res. Let. (2012) Marcq et al., Variations of sulphur dioxide at the cloud top of Venus's dynamic atmosphere, Nature Geoscience (2013)

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. Lunar and Planetary Science XXXV: Venus

    NASA Technical Reports Server (NTRS)

    2004-01-01

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

  6. 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.

  7. 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.

  8. 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.

  9. 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.)

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Understanding the structure and dynamics of Venus' clouds is essential as they have a strong impact on the radiative balance and atmospheric chemistry of the planet. Polarimetry has greatly contributed to our knwoledge about the properties of the cloud layers located between 48 and ~ 70 km. Hansen and Hovenier (1974), using ground-based observations, found the cloud particles to be ~ 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

  11. 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

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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

  17. High temperature, high intensity solar array. [for Venus Radar Mapper mission

    NASA Technical Reports Server (NTRS)

    Smith, B. S.; Brooks, G. R.; Pinkerton, R.

    1985-01-01

    The solar array for the Venus Radar Mapper mission will operate in the high temperature, high intensity conditions of a low Venus orbit environment. To fulfill the performance requirements in this environment at minimum cost and mass while maximizing power density and packing factor on the panel surface, several features were introduced into the design. These features included the use of optical surface reflectors (OSR's) to reduce the operating temperature; new adhesives for conductive bonding of OSR's to avoid electrostatic discharges; custom-designed large area cells and novel shunt diode circuit and panel power harness configurations.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. The Surface of Venus and Implications for its Geological and Geodynamical Evolution: The View Before Venus Express and Outstanding Questions for the Future

    NASA Astrophysics Data System (ADS)

    Head, J. W.; Ivanov, M. A.; Basilevsky, A. T.

    2008-12-01

    thickness variations and mantle convection patterns. The relationships of major elements of global topography and the sequence of events in the observed geological history (as recorded by major geologic units and structures) suggest that much of the current long-wavelength topography of Venus (tessera highlands and lowlands with regional plains) may have formed prior to emplacement of regional plains and been preserved since that time. These observations may favor evolutionary geodynamic models that are characterized by changes in geological style and rates, and may involve non-linear heat loss mechanisms that could have profound influence on the atmosphere. Although the observed surface of Venus dates from relatively recent planetary history, comparative planetology permits inferences to be made about the major stages in the earlier history of Venus. The evolution of the understanding of the surface from early speculations to present observations and interpretations provides an important context for: 1) establishing the relationships of the surface of Venus to the nature of the atmosphere and its evolution as assessed by Venus Express, 2) the comparison of the geological features and history of Venus relative to the Moon, Mars, Mercury and the Earth, and 3) defining the major outstanding problems and questions to be addressed by future experiments and missions to Venus.

  7. 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

  8. Analysis of Venusian Zonal Winds Using Venus Express Data

    NASA Astrophysics Data System (ADS)

    McCabe, Ryan M.; Sayanagi, Kunio M.; Blalock, John J.; Peralta, Javier; Gray, Candace L.; McGouldrick, Kevin; Imamura, Takeshi

    2016-10-01

    We measure the zonal mean wind structure of Venus between 2006 and 2013 in the ultraviolet images captured by the Venus Monitoring Camera (VMC) onboard the ESA Venus Express spacecraft. Our wind measurements employ the digital two-dimensional Correlation Imaging Velocimetry method to track cloud motions. Our current focus is on understanding the short- and long-term dynamics of Venus's atmospheric superrotation, in which the equatorial atmosphere rotates with a period of approximately 4-5 days (~60 times faster than the solid planet). The Venusian atmospheric superrotation's forcing and maintenance mechanisms remain to be explained. A number of studies have been published on the cloud-tracking wind measurements on Venus, however, those different measurements have not reached a consensus on the temporal evolution of the zonal wind structure (e.g., Kouyama et al 2013, Khatuntsev et al 2013, Patsaeva et al. 2015). Temporal evolution of the zonal wind could reveal the transport of energy and momentum and eventually shed a light on mechanisms that maintain the superrotation. Our first goal is to characterize the temporal dynamics of Venus's zonal wind profile and two-dimensional wind field, in which we will search for equatorial waves (in particular the so-called "Y-feature") that may force the Venusian atmospheric superrotation.Kouyama, T. et al (2013), J. Geophys. Res. Planets, 118, 37–46, doi:10.1029/2011JE004013.Khatuntsev et al. (2013), Icarus, 226, 140-158, doi:10.1016/j.icarus.2013.05.018.Patsaeva,M.V.,et al. (2015), Planetary and Space Science, 113, 100-108, doi:10.1016/j.pss.2015.01.013.

  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. 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.

  12. 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.

  13. Neutral atmosphere composition from SOIR measurements on board Venus Express

    NASA Astrophysics Data System (ADS)

    Mahieux, A.; Drummond, R.; Wilquet, V.; Vandaele, A. C.; Federova, A.; Belyaev, D.; Korablev, O.; Villard, E.; Montmessin, F.; Bertaux, J.-L.

    2009-04-01

    The SOIR instrument performs solar occultation measurements in the IR region (2.2 - 4.3 m) at a resolution of 0.12 cm-1, the highest on board Venus Express. It combines an echelle spectrometer and an AOTF (Acousto-Optical Tunable Filter) for the order selection [1,2]. The wavelength range probed by SOIR allows a detailed chemical inventory of the Venus atmosphere above the cloud layer with an emphasis on vertical distribution of the gases. Measurements of HDO, H2O, HCl, HF, CO and CO2 vertical profiles have been routinely performed, as well as those of their isotopologues [3,4]. We will discuss the improvements introduced in the analysis algorithm of the SOIR spectra. This discussion will be illustrated by presenting new results of retrievals of minor constituents of the Venus mesosphere, in terms of vertical profiles and geographical distribution. CO2 is the major constituent of the Venus atmosphere and was therefore observed in many solar occultations, leading to a good geographical coverage, although limited by the geometry of the orbit. Depending on the abundance of the absorbing isotopologue and on the intensity of the band measured, we will show that the SOIR instrument is able to furnish CO2 vertical profiles ranging typically from 65 to 150 km, reaching in some conditions 185 km altitude. This information is important in the frame of compiling, in collaboration with other teams, a new Venus Atmosphere Model. 1. A. Mahieux, S. Berkenbosch, R. Clairquin, D. Fussen, N. Mateshvili, E. Neefs, D. Nevejans, B. Ristic, A. C. Vandaele, V. Wilquet, D. Belyaev, A. Fedorova, O. Korablev, E. Villard, F. Montmessin and J.-L. Bertaux, "In-Flight performance and calibration of SPICAV SOIR on board Venus Express", Applied Optics 47 (13), 2252-65 (2008). 2. D. Nevejans, E. Neefs, E. Van Ransbeeck, S. Berkenbosch, R. Clairquin, L. De Vos, W. Moelans, S. Glorieux, A. Baeke, O. Korablev, I. Vinogradov, Y. Kalinnikov, B. Bach, J.-P. Dubois and E. Villard, "Compact high

  14. 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.

  15. 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.

  16. 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.

  17. Electronics and Sensor Cooling with a Stirling Cycle for Venus Surface Mission

    NASA Technical Reports Server (NTRS)

    Mellott, Ken

    2004-01-01

    The inhospitable ambient surface conditions of Venus, with a 450 C temperature and 92 bar pressure, may likely require any extended-duration surface exploratory mission to incorporate some type of cooling for probe electronics and sensor devices. A multiple-region Venus mission study was completed at NASA GRC in December of 2003 that resulted in the preliminary design of a kinematically-driven, helium charged, Stirling cooling cycle with an estimated over-all COP of 0.376 to lift 100 watts of heat from a 200 C cold sink temperature and reject it at a hot sink temperature of 500 C. This paper briefly describes the design process and also describes and summarizes key features of the kinematic, Stirling cooler preliminary design concept.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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).

  3. 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

  4. Models of the global cloud structure on Venus derived from Venus Express observations

    NASA Astrophysics Data System (ADS)

    Barstow, J. K.; Tsang, C. C. C.; Wilson, C. F.; Irwin, P. G. J.; Taylor, F. W.; McGouldrick, K.; Drossart, P.; Piccioni, G.; Tellmann, S.

    2012-02-01

    Spatially-resolved near-infrared spectra from the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express have been used to derive improved models of the vertical structure and global distribution of cloud properties in the southern hemisphere of Venus. VIRTIS achieved the first systematic, global mapping of Venus at wavelengths within transparency windows in the 1.6-2.6 μm range, which are sensitive on the nightside to absorption by the lower and middle cloud layers of thermally-emitted radiation from the hot lower atmosphere ( Taylor, F.W., Crisp, D., Bézard, B. [1997]. Venus II: Geology, Geophysics, Atmosphere, and Solar Wind Environment, pp. 325-351). The cloud model used to interpret the spectra is based on previous work by Pollack et al. (Pollack, J., Dalton, J., Grinspoon, D., Wattson, R., Freedman, R., Crisp, D., Allen, D., Bézard, B., de Bergh, C., Giver, L. [1993]. Icarus 103, 1-42), Grinspoon et al. (Grinspoon, D.H., Pollack, J.B., Sitton, B.R., Carlson, R.W., Kamp, L.W., Baines, K.H., Encrenaz, T., Taylor, F.W. [1993]. Planet. Space Sci. 41, 515-542) and Crisp (Crisp, D. [1986]. Icarus 67, 484-514), and assumes a composition for the cloud particles of sulfuric acid and water, with acid concentration as a free parameter to be determined. Other retrieved parameters are the average size of the particles and the altitude of the cloud base in the model. Latitudinal variation in the atmospheric temperature structure was incorporated using data from the Venus Radio Science experiment (VeRa). Values are estimated initially using wavelength pairs selected for their unique sensitivity to each parameter, and then validated by comparing measured to calculated spectra over the entire wavelength range, the latter generated using the NEMESIS radiative transfer and retrieval code (Irwin, P.G.J., Teanby, N.A., de Kok, R., Fletcher, L.N., Howett, C.J.A., Tsang, C.C.C., Wilson, C.F., Calcutt, S.B., Nixon, C.A., Parrish, P.D. [2008]. J. Quant

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

    PubMed

    Schulze-Makuch, Dirk; Irwin, Louis N

    2002-01-01

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

  6. 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

  7. Venus 3 Book: Chapter 1

    NASA Astrophysics Data System (ADS)

    Taylor, F.; Svedhem, H.; Head, J.

    2014-04-01

    This will be the first chapter in the planned 'Venus 3' book, which will present the latest knowledge about all aspects of the planet Venus. Chapter 1 will include: 1. Brief history of Venus observations, from telescopic studies up to and including early space missions (Venera, Mariner) 2. Overview of key results from more recent groundbased observations and space missions, including Pioneer Venus, the later Veneras, Vega, Magellan, Akatsuki and Venus Express 3. Summary of current knowledge, in three main sections: a. Surface and interior b. Atmosphere and climate c. Thermosphere, exosphere and magnetosphere 4. Outstanding scientific questions remaining, and future mission concepts providing background, introduction and an overview to the rest of the book.

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

    NASA Technical Reports Server (NTRS)

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

    1960-01-01

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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. Access to VIRTIS / Venus-Express post-operations data archive

    NASA Astrophysics Data System (ADS)

    Erard, Stéphane; Drossart, Pierre; Piccioni, Giuseppe; Henry, Florence; Politi, Romolo

    2016-10-01

    All data acquired during the Venus-Express mission are publicly available on ESA's Planetary Science Archive (PSA). The PSA itself is being redesigned to provide more comprehensive access to its content and a new interface is expected to be ready in the coming months.However, an alternative access to the VIRTIS/VEx dataset is also provided in the PI institutes as part of the Europlanet-2020 European programme. The VESPA user interface (http://vespa.obspm.fr) provides a query mechanism based on observational conditions and instrument parameters to select data cubes of interest in the PSA and to connect them to standard plotting and analysis tools. VESPA queries will also identify related data in other datasets responsive to this mechanism, e. g., contextual images or dynamic simulations of the atmosphere, including outcomes of the EuroVenus programme funded by the EU. A specific on-line spectral cube viewer has been developed at Paris Observatory (http://voplus.obspm.fr/apericubes/js9/demo.php). Alternative ways to access the VIRTIS data are being considered, including python access to PDS3 data (https://github.com/VIRTIS-VEX/VIRTISpy) and distribution in NetCDF format on IAPS website (http://planetcdf.iaps.inaf.it). In the near future, an extended data service will provide direct access to individual spectra on the basis of viewing angles, time, and location.The next step will be to distribute products derived from data analysis, such as surface and wind maps, atmospheric profiles, movies of the polar vortices or O2 emission on the night side, etc. Such products will be accessed in a similar way, and will make VIRTIS results readily available for future Venus studies. Similar actions are taken in the frame of Europlanet concerning atmospheric data from the Mars-Express mission and Cassini observations of Titan.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    2006-04-01

    During the next four weeks, the Venus Express probe will perform a series of manoeuvres to reach the scheduled operational orbit for its scientific mission. It will move from its current highly elongated 9-day orbit to a 24-hour polar orbit, culminating at 66,000 km. From this vantage point, the orbiter will conduct an in-depth observation of the structure, chemistry and dynamics of the atmosphere of Venus for at least two Venusian days (486 Earth days). Enigmatic atmosphere From previous missions to Venus as well as observations directly from Earth, we already know that our neighbouring planet is shrouded in a thick atmosphere where extremes of temperature and pressure conditions are common. This atmosphere creates a greenhouse effect of tremendous proportions as it spins around the planet in four days in an unexplained “super-rotation” phenomenon. The mission of Venus Express will be to carry out a detailed characterisation of this atmosphere, using state-of-the-art sensors in order to answer the questions and solve the mysteries left behind by the first wave of explorers. It will also be the first Venus orbiter to conduct optical observations of the surface through “visibility windows” discovered in the infrared spectrum.V The commissioning of the onboard scientific instruments will begin shortly and the first raw data are expected within days. The overall science payload is planned to be fully operational within two months. Europe explores the Solar System With this latest success, ESA is adding another celestial body to its range of solar system studies. ESA also operates Mars Express around Mars, SMART-1 around the Moon and is NASA’s partner on the Cassini orbiter around Saturn. In addition, ESA is also operating the Rosetta probe en route to comet 67P/Churyumov-Gerasimenko. It should reach its target and become the first spacecraft ever to enter orbit around a comet nucleus by 2014. Meanwhile, ESA also plans to complete the survey of our celestial

  19. 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.

  20. No statistical evidence of lightning in Venus night-side atmosphere from VIRTIS-Venus Express Visible observations

    NASA Astrophysics Data System (ADS)

    Cardesín Moinelo, A.; Abildgaard, S.; García Muñoz, A.; Piccioni, G.; Grassi, D.

    2016-10-01

    In this study we describe a dedicated analysis of luminous transient events on Venus night side atmosphere with the visible channel of the VIRTIS instrument (280-1100 nm), this being the most comprehensive search of lightning conducted so far with Venus Express data. Our search results in thousands of signal detections, but unfortunately they can be all explained by cosmic rays impinging on the detector, and further statistical analysis shows that all of the events are randomly distributed along the spectral dimension, therefore not showing any clear evidence of signal coming from lightning emission in the Venus atmosphere. This does not exclude the existence of lightning, but imposes some constraints on their occurrence that are important for future research.

  1. 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.

  2. 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

  3. 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

  4. Investigation of the HDO/H2O ratio on Venus from SOIR solar occultations on board Venus Express

    NASA Astrophysics Data System (ADS)

    Matsui, H.; Mahieux, A.; Robert, S.; Wilquet, V.; Drummond, R.; Vandaele, A. C.; Iwagami, N.; Bertaux, J.-L.

    2012-04-01

    The SOIR instrument performs solar occultation measurements in the IR region (2.2 - 4.3 μm) at a resolution of 0.12 cm-1, the highest on board Venus Express. It combines an echelle spectrometer and an AOTF (Acousto-Optical Tunable Filter) for the order selection. The wavelength range probed by SOIR allows a detailed chemical inventory of the Venus atmosphere at the terminators in the upper mesosphere and lower thermosphere (70 to 170 km) with an emphasis on vertical distribution of the gases. H2O and HDO have been routinely monitored at various latitudes of the Venus terminator, using the temperature profiles obtained from the SOIR CO2 density profiles. The HDO/H2O ratios are obtained from an altitude region extending from 70 km up to 100 km, and show a vertical gradient. Observations made at the IRTF telescope in Hawaii in 2010 showed a disk-averaged mixing ratio of HDO is 0.22 ± 0.03 ppm for a representative height region of 62-67 km. Based on many previous H2O measurements, the HDO/H2O ratio is found to be 140 ± 20 times larger than the telluric ratio. This lies between the ratios of 120 ± 40 and 240 ± 25, respectively, reported for the 30-40 km region [De Bergh et al. 1991] by ground-based night-side spectroscopy and for the 80-100 km region by solar occultation measurement on board the Venus Express [Fedorova et al. 2008]. In addition to this, past observations at an altitude of 70 km show that HDO on Venus in the early evening shows a latitudinal structure, and HDO mixing ratio at higher latitude is two times larger that in the lower latitude regions. So there is probably a vertical distribution or/and a latitudinal structure. From measurements obtained by SOIR on Venus Express at the Venus terminator, the D/H ratio seems to be very variable, and we confirm that the D/H ratio is larger at higher altitude.

  5. 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.

  6. 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.

  7. Inflight calibration technique for onboard high-gain antenna pointing. [of Mariner 10 spacecraft in Venus and Mercury flyby mission

    NASA Technical Reports Server (NTRS)

    Ohtakay, H.; Hardman, J. M.

    1975-01-01

    The X-band radio frequency communication system was used for the first time in deep space planetary exploration by the Mariner 10 Venus and Mercury flyby mission. This paper presents the technique utilized for and the results of inflight calibration of high-gain antenna (HGA) pointing. Also discussed is pointing accuracy to maintain a high data transmission rate throughout the mission, including the performance of HGA pointing during the critical period of Mercury encounter.

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. The Structure of the Venus Neutral Atmosphere from the Radio Science Experiment VeRa on Venus Express

    NASA Astrophysics Data System (ADS)

    Tellmann, S.; Häusler, B.; Pätzold, M.; Bird, M.; Tyler, G. L.

    2007-08-01

    The Venus Express Radio Science Experiment VeRa uses one-way radio signals at X-band and S-band for the sounding of the Venus neutral atmosphere and ionosphere. An Ultrastable Oscillator (USO) provides a high quality onboard frequency reference source for this dual-frequency one-way radio link. Simultaneous, coherent measurements at two wavelengths allow separation of dispersive media effects from the classical Doppler shift. Electron density profiles of the ionosphere and profiles of pressure, temperature and neutral number density of the neutral atmosphere can be derived via an Abel transform with an altitude resolution of only a few hundred metres from the cloud deck to ~ 100 km. Two occultation seasons took place in the first year of observation. A total number of 42 profiles occultation experiments were conducted. The polar orbit of Venus Express provides the opportunity to study the atmosphere at all planetocentric latitudes under varying illumination conditions. Special attention will be given to day-night variations of the atmospheric structure and the temperature distribution at high polar latitudes on both hemispheres ("cold collar region") and signal absorption effects caused by the H2SO4 vapour.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Correlations between Venus nightside near infrared emissions measured by VIRTIS/Venus Express and Magellan radar data

    NASA Astrophysics Data System (ADS)

    Mueller, N.; Helbert, J.; Hashimoto, G. L.; Tsang, C. C. C.; Erard, S.; Piccioni, G.; Drossart, P.

    2008-09-01

    Background The Venus Express Spacecraft images the nightside thermal emissions using the VIRTIS imaging spectrometer. At 1.02 micron thermal emission from the surface is penetrates the atmosphere but the signal is attenuated by scattering and absorption [1, 2]. Although the measured flux at top of the atmosphere is nonlinearly related to the original emission of the surface, it is still positively correlated with the product of surface temperature and surface emissivity [3]. The surface temperature of Venus is relatively well constrained as a monotonous function of altitude. Emissivity at 1 micron depends strongly on surface composition, in particular abundance of mafic minerals [3]. Mapping the thermal emission of the surface of Venus therefore supplements radar data as it allows to infer relative variation of surface composition. Data Processing This study examines the correlation of VIRTIS images showing a signal of the surface with all known parameters that govern radiance and applies semi empirical relations to remove the respective influences. 1. Stray sunlight is removed by subtraction of a spectrum template scaled to fit radiance at 1.4 ¹m [2] 2. Limb darkening is accounted for using a linear phase function consistent with results of radiative transfer modeling [4]. 3. Cloud opacity is determined from 1.31 ¹m and applied to 1.02 ¹m while accounting for multiple reflections between lower atmosphere and clouds [3]. Result is brightness temperature of thermal emission below the cloud deck but above the lowest 20 km of the atmosphere. 4. Influence of surface temperature and lower atmosphere absorption is determined by correlation of VIRTIS declouded brightness temperature and Magellan Topography data [5]. To further reduce the influence of cloud contrast and increase the signal of the surface, all suitable VIRTIS observations are map projected and stacked to create a map of the southern hemisphere of Venus. Observations and Interpretation As expected from

  19. The evolution of co-orbiting material in the orbit of 2201 Oljato from 1980 to 2012 as deduced from Pioneer Venus Orbiter and Venus Express magnetic records

    NASA Astrophysics Data System (ADS)

    Lai, Hairong; Russell, Christopher T.; Wei, Hanying; Zhang, Tielong

    2014-01-01

    Asteroid 2201 Oljato passed through perihelion inside the orbit of Venus near the time of its conjunction with Venus in 1980, 1983, and 1986. During those three years, many interplanetary field enhancements (IFEs) were observed by the Pioneer Venus Orbiter (PVO) in the longitude sector where the orbit of Oljato lies inside Venus' orbit. We attribute IFEs to clouds of fine-scale, possibly highly charged dust picked up by the solar wind after an interplanetary collision between objects in the diameter range of 10-1000 m. We interpret the increase rate in IFEs at PVO in these years as due to material in Oljato's orbit colliding with material in, or near to, Venus' orbital plane and producing a dust-anchored structure in the interplanetary magnetic field. In March 2012, almost 30 yr later, with Venus Express (VEX) now in orbit, the Oljato-Venus geometry is similar to the one in 1980. Here, we compare IFEs detected by VEX and PVO using the same IFE identification criteria. We find an evolution with time of the IFE rate. In contrast to the results in the 1980s, the recent VEX observations reveal that at solar longitudes in which the Oljato orbit is inside that of Venus, the IFE rate is reduced to the level even below the rate seen at solar longitudes where Oljato's orbit is outside that of Venus. This observation implies that Oljato not only lost its co-orbiting material but also disrupted the "target material," with which the co-orbiting material was colliding, near Venus.

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

    NASA Astrophysics Data System (ADS)

    Patsaeva, Marina; Khatuntsev, Igor; Ignatiev, Nikolai

    2013-04-01

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

  1. 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

  2. Generation of Venus reporter knock-in mice revealed MAGI-2 expression patterns in adult mice.

    PubMed

    Ihara, Kan-ichiro; Nishimura, Tomoki; Fukuda, Tomokazu; Ookura, Tetsuya; Nishimori, Katsuhiko

    2012-01-01

    The membrane-associated guanylate kinase inverted 2 (MAGI-2) protein, which is known to localize at the tight junction of epithelial cells, contains multiple copies of the PDZ and WW domains in its structure. Although the expression pattern of Magi2 mRNA in representative organs has been previously published, its detailed cellular distribution at the histological level remains unknown. Such detailed information would be useful to clarify the biological function of MAGI-2. Here, we report the generation of Venus reporter knock-in mice for Magi2 in which exon 6 of the gene was substituted by the Venus-encoding sequence. We detected the expression of the Venus reporter protein in kidney podocytes from these knock-in mice. We also detected Venus reporter protein expression in spermatids within the testes and within neurons in various regions of the brain. Detection of the reporter protein from these diverse locations indicated the endogenous expression of MAGI-2 in these tissues. Our data suggested a potential function of MAGI-2 in the glomerular filtration process and sperm cell maturation. These data indicate that the Venus reporter knock-in mouse for Magi2 is a useful model for the further study of Magi2 gene function.

  3. 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.

  4. Oxygen nightglow emissions in the Venus atmosphere, observed by the visible channel of VIRTIS/Venus Express

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Piccioni, G.; Gérard, J.-C.; Slanger, T.; Snels, M.,; Drossart, P.

    2012-04-01

    The oxygen nightglow emissions in the visible spectral range have been known since the early observations with the Venera spacecraft. The VIRTIS instrument on board Venus-Express allows extension of observations of the Herzberg II system of O2, and we report a mean value of 200 kR for the integrated intensity of the progression in limb view. Moreover, three bands of the Chamberlain system have been detected in the VIRTIS mean spectrum, with a mean intensity of 8-10 kR for the most intense of these bands. For the 0-v″ progression of the Herzberg II system, with v″ = 6-13, the maximum emission is typically observed at 95-96 km, with a full width at half maximum ranging from 12 to 15 km. A systematic observing campaign at limb is in progress from Venus Express, which will allow mapping the horizontal spatial distribution of these emissions. Once the map is enough populated, it will be possible to compare the results obtained both in the visible and IR for the O2 nightglow emissions, although not simultaneously.

  5. 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.

  6. 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.

  7. 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

  8. VERITAS (Venus Emissivity, Radio Science, InSAR, Topo-graphy And Spectroscopy): A Proposed Discovery Mission

    NASA Astrophysics Data System (ADS)

    Smrekar, Suzanne; Dyar, Melinda; Hensley, Scott; Helbert, Joern; VERITAS Science Team

    2016-10-01

    VERITAS addresses one of the most fundamental questions in planetary evolution: How Earth-like is Venus? These twin planets diverged down different evolutionary paths, yet Venus may hold lessons for past and future Earth, as well as for Earth-sized exoplanets. VERITAS will search for the mineralogical fingerprints of past water, follow up on the discoveries of recent volcanism and the possible young surface age, and reveal the conditions that have prevented plate tectonics from developing. Collectively these questions address how Venus ended up a sulfurous inferno while Earth became habitable.VERITAS carries the Venus Interferometric Synthetic Aperture Radar (VISAR) and the Venus Emissivity Mapper (VEM), plus a gravity science investigation.The VISAR X-band radar produces: 1) a global digital elevation model (DEM) with 250 m postings, 5 m height accuracy, 2) Synthetic aperture radar (SAR) global imaging with 30 m pixels, 3) SAR imaging at 15 m for targeted areas, and 4) surface deformation from repeat pass interferometry (RPI) at 2 mm height precision for targeted, potentially active areas. VEM [see Helbert abstract] will measure surface emissivity, look for active volcanic flows and outgassing of water over ~78% of the surface using 6 NIR surface bands within 5 atmospheric windows and 8 bands for calibration of clouds, stray light, and water vapor.VERITAS uses Ka-band uplink and downlink to create a global gravity field with 3 mgal accuracy and 145 km resolution (130 spherical harmonic degree and order or d&o) and providing a significantly higher resolution field with much more uniform resolution than that available from Magellan.VERITAS will create a rich data set of high resolution topography, imaging, spectroscopy, and gravity. These co-registered data sets will be on par with those acquired for Mercury, Mars and the Moon that have revolutionized our understanding of these bodies. VERITAS would be a valuable asset for future lander or probe missions, collecting

  9. In-flight performance and calibration of SPICAV SOIR onboard Venus Express.

    PubMed

    Mahieux, Arnaud; Berkenbosch, Sophie; Clairquin, Roland; Fussen, Didier; Mateshvili, Nina; Neefs, Eddy; Nevejans, Dennis; Ristic, Bojan; Vandaele, Ann Carine; Wilquet, Valérie; Belyaev, Denis; Fedorova, Anna; Korablev, Oleg; Villard, Eric; Montmessin, Franck; Bertaux, Jean-Loup

    2008-05-01

    Solar occultation in the infrared, part of the Spectoscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument onboard Venus Express, combines an echelle grating spectrometer with an acousto-optic tunable filter (AOTF). It performs solar occultation measurements in the IR region at high spectral resolution. The wavelength range probed allows a detailed chemical inventory of Venus's atmosphere above the cloud layer, highlighting the vertical distribution of gases. A general description of the instrument and its in-flight performance is given. Different calibrations and data corrections are investigated, in particular the dark current and thermal background, the nonlinearity and pixel-to-pixel variability of the detector, the sensitivity of the instrument, the AOTF properties, and the spectral calibration and resolution.

  10. 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.

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

    NASA Technical Reports Server (NTRS)

    Bender, D. F.

    1979-01-01

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

  12. 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

  13. 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.

  14. 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.

  15. Updating the Venus International Reference Atmosphere (VIRA)

    NASA Astrophysics Data System (ADS)

    Limaye, S.; Svedhem, H.; Titov, D.; Markiewicz, W.; Wilson, C.; Zasova, L.

    2012-04-01

    The compilation of the Venus International Reference Atmosphere was completed in 1985 through the initiative of A.J. Kliore, V.I. Moroz, and G.M. Keating. Consisting of seven chapters, it presented a synthesis of the best available data at that time on the neutral atmosphere and ionosphere of Venus.This model consist of seven chapters: (1 ) Models of the structure of the atmosphere of Venus from the surface to 100 km altitude,(2) Circulation of the atmosphere from surface to 100 km, (3) Particulate matter in the Venus atmosphere, (4) Models of Venus neutral upper atmosphere: structure and composition, (5) Composition of the atmosphere below 100 km altitude, (6) Solar and thermal radiation in the Venus atmosphere, and (7) The Venus ionosphere. VIRA provides tables and figures as well as description of how the models were synthesized from the available data and references. VIRA has helped many studies of Venus since its publication and in fact has proved invaluable in comparing and contrasting many studies by providing a common standard for atmospheric data.The organizers of VIRA had anticipated updating the model soon after publication as newer data were becoming available from Pioneer and Venera missions.Since then many other missions have yielded valuable data and newer findings. In particular the Venus Express mission is currently providing many new details of the atmospheric structure and radiation balance from its instruments, so an effort to update VIRA is timely. The Venus community continues to consider new missions to address the unanswered questions about Venus and hence updating the Reference Model in the near future will help both future studies and understanding the available observations through models that need the information. The Venus Exploration Analysis Group (VEXAG) sponsored by NASA provides an international forum to carry out the required effort and invites Venus scientists to propose models and participate in working group to update the model

  16. The Venus Emissivity Mapper

    NASA Astrophysics Data System (ADS)

    Helbert, Joern; Marcq, Emmanuel; Widemann, Thomas; Mueller, Nils; Kappel, David; Tsang, Constantine; Maturilli, Alessandro; Ferrari, Sabrina; D'Amore, Mario; Dyar, Melinda; Smrekar, Suzanne

    2016-10-01

    The permanent cloud cover of Venus prohibits observations of the surface with traditional imaging techniques over the entire visible spectral range. Fortunately, Venus' atmospheric gases are largely transparent in narrow spectral windows near 1 mm. Ground observers were the first to successfully use these windows, followed by spacecraft observations during the flyby of the Galileo mission on its way to Jupiter and most recently from Venus orbit by ESA's Venus Express with the VMC and VIRTIS instruments. Analyses of VIRTIS measurements have successfully demonstrated that surface information can be extracted from these windows, but the design of the instrument limited its use for more in-depth surface investigations.Based on experience gained from using VIRTIS to observe the surface of Venus and new high temperature laboratory experiments currently performed at the Planetary Spectroscopy Laboratory of DLR, we have designed the multi-spectral Venus Emissivity Mapper (VEM). Observations from VIRTIS have revealed surface emissivity variations correlated with geological features, but existing data sets contain only three spectral channels. VEM is optimized to map the surface composition and texture, and to search for active volcanism using the narrow atmospheric windows, building on lessons from prior instrumentation and methodology. It offers an opportunity to gain important information about surface mineralogy and texture by virtue of having six different channels for surface mapping.VEM is focused mainly on observing the surface, mapping in all near-IR atmospheric windows using filters with spectral characteristics optimized for the wavelengths and widths of those windows. It also observes bands necessary for correcting atmospheric effects; these bands also provide valuable scientific data on composition as well as altitude and size distribution of the cloud particles, and on H2O vapor abundance variations in the lowest 15 km of the atmosphere.In combination with a

  17. Venus: Mysteries Of The "forgotten Planet"

    NASA Astrophysics Data System (ADS)

    Titov, D. V.

    T: none of the worldSs space agencies & cedil; has considered it as a primary target. However, a great number of unsolved funda- mental problems in VenusS physics and availability of observational tools encourages the scientific community to propose missions to the planet. Venus Express in Europe and a set of Discovery missions in USA are being currently considered for inclusion in the programmes of space agencies. The Venus Orbiter mission has been recently approved in Japan.

  18. 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.

  19. 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.

  20. Circulation of mesosphere of Venus according to wind tracking results obtained from VMC and VIRTIS onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Patsaeva, Marina; Khatuntsev, Igor; Ignatiev, Nikolay

    2012-07-01

    Six years of permanent monitoring of the Venus' cloud layer by the ESA spacecraft Venus Express (VEx) provided the opportunity to study dynamics of various mesospheric layers. UV images provided by the VMC allowed studying the circulation at the top cloud layer. 550 orbits covering about 10 Venusian years have been processed by means of an automated cloud tracking method giving 400000 displacement vectors. Average zonal and meridional wind profiles have been calculated, and vector fields of wind velocities in latitude-time coordinates have been built. The plots show that zonal and meridional wind velocities depend on local time. A diurnal wave of zonal wind velocity at the equatorial region can be seen clearly. It has maximum at 9 a.m. which is in good agreement with data obtained by the FS onboard Venera-15. The average wind velocity at the equator is 97±2 m/s. The period of zonal rotation has maximum (about 5 terrestrial days) at the equator and minimum (3 terrestrial days) at the latitude 50S. The visual cloud tracking method, due to better sensitivity to small image details at middle and high latitudes, shows a jet at the latitude 50S±3. Having maximum at 50S, the zonal wind velocity decreases to the South pole in linear fashion. The meridional wind velocity is about 0 m/s at the equator, increases in linear fashion to -10 m/s (the negative velocity represents the flow from the equator to the South pole) at 50S, and decreases to a low positive value at 75S. Within the equatorial region, up to 35S, the zonal wind velocity oscillates with a period about 4.83 days which is close to the super-rotation period at the equator. The average oscillation amplitude is 4.28 m/s and the maximum amplitude is 17.44 m/s. The oscillation amplitude of the zonal wind velocity depends on latitude. The oscillation amplitude and phase change with time, but can be stable as long as 70 days. VIRTIS images for the 1.27 μ m spectral band (molecular oxygen airglow), obtained at the

  1. A study of magnetic clouds observed by MESSENGER and Venus Express

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    We present an analysis of a recently compiled list of magnetic clouds observed by the MESSENGER and Venus Express spacecraft. Despite their planetary focus, both spacecraft spent significant amounts of time in the solar wind, allowing transient solar wind structures such as magnetic clouds to be observed. The clouds were observed at a range of heliocentric distances (at 0.72 AU by Venus Express, and from 1 to 0.3 AU by MESSENGER) over the course of a significant fraction of a solar cycle (2006 to 2013 by Venus Express, and 2007 to 2012 by MESSENGER). Neither spacecraft carried a dedicated solar wind plasma instrument, and so the clouds have been identified using magnetic field data only: a coherent rotation of the magnetic field direction lasting for at least four hours that coincides with a field strength above that of the ambient solar wind were the primary identification criteria. The approximate orientations of the magnetic clouds relative to the solar equatorial plane have been found. We consider the frequency distribution of these orientations, and their dependence on heliocentric distance and the solar magnetic field configuration. We also use these observations, in conjunction with observations at 1 AU, to estimate the likelihood that two spacecraft will encounter the same magnetic cloud as a function of the spacecraft's azimuthal separation.

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  3. 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

  4. 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.

  5. 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.

  6. [Construction of venus vector carrying IGFBP7 gene and its expression in K562 cells].

    PubMed

    Wu, Shui-Yan; Hu, Shao-Yan; Cen, Jian-Nong; Chen, Zi-Xing

    2012-02-01

    The aim of this study was to construct venus vector carrying the gene encoding insulin-like growth factor binding protein 7 (IGFBP7), which provides an effective platform for exploring the function of this gene in leukemia. After digestion by restriction endonuclease, the IGFBP7 gene was recombined with the transfer plasmid. The venus particles were packaged using 293T cells to transfect K562 cells, and identification was performed by means of flow cytometry, RT-PCR and Western blot. The results showed that the sequence of cloned IGFBP7 gene was the same as that in GenBank. The size of product restricted by BamHI was same as the predicted one. GFP expression was observed in 293T and K562 cells with the fluorescent microscopy and flow cytometry. The expression level of mRNA and protein of IGFBP7 was confirmed by RT-PCR and Western blotting in K562 cells. It is concluded that venus vector carrying IGFBP7 gene has been successfully constructed and provides basis for exploring function of IGFBP7 in K562 cells.

  7. Venus volcanism

    SciTech Connect

    Head, J.W.

    1985-01-01

    Eruption styles and processes on the planets are known to be strongly influenced by such factors as gravity, temperature, and atmospheric characteristics. The ascent and eruption of magma on Venus in the current Venus environment must take into account the influence of the extreme surface temperatures (650-750 K) and pressures (40-100 bars) on these processes. Conditions on Venus will reduce the subsurface exsolution of volatiles and lead to a reduction of the possible range of explosive interactions with the atmosphere. Pyroclastic eruptions will be severely inhibited and continuous magma disruption by gas bubble growth may not occur at all unless the exsolved magma volatile content exceeds several weight percent. Recent US and USSR spacecraft missions and Earth-based radar observations are beginning to provide a view of the range of Venus volcanic features, including domes, cones, calderas, shields, and flows. The nature of many lava flows suggests that numerous eruptions have effusion rates exceeding common terrestrial rates and lying more in the range inferred for lunar basaltic flood eruptions (10/sup 4/-10/sup 5/m/sup 3//s). Shield volcanoes are often wide but are low (<2 km elevation) relative to those on Mars and the Earth. Volcano height depends in part on the depth of origin of the magma and the density contrast between the lava and the rocks between the source and the surface, both of which may be different on Venus. Correlations between volcanic style and tectonic structure are emerging.

  8. Shoemaker Lecture: The Atmosphere and Climate of Venus

    NASA Astrophysics Data System (ADS)

    Taylor, F. W.

    2006-12-01

    Venus is like another Earth, orbiting closer to the Sun. Its cloudy atmosphere reflects so much of the Sun's heat that, on simple energy balance grounds, we might expect Venus to be cooler than Earth. In fact, its surface glows with a dull red heat and some metals would be molten there. This fantastic case of global warming is due to a greenhouse effect very similar, though stronger, than that which is now threatening to overheat the Earth. What lessons should we draw from this? Can we explain the evolutionary tracks of Venus, Earth and Mars with a common paradigm? What key investigations should we be making, particularly in terms of space missions? The European Space Agency responded recently to calls from the scientific community there for a new mission to Venus, and produced the Venus Express orbiter. This has now been operating at Venus since April, and early results are beginning to flow. We discuss the interesting questions about Venus that Venus Express is addressing and discuss current and expected progress and remaining mysteries.

  9. 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

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

    NASA Astrophysics Data System (ADS)

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

    2006-11-01

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

  11. 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

  12. 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.

  13. Studying the surface composition of Venus from orbit

    NASA Astrophysics Data System (ADS)

    Helbert, J.; Mueller, N. T.; Maturilli, A.; D'Incecco, P.; Smrekar, S. E.; Nadalini, R.

    2013-12-01

    The atmosphere of Venus allows observations of the surface only in very narrow spectral windows around 1 micron. These have been successfully used by the VenusExpress, Galileo and Cassini spacecrafts as well as by ground-based observers. For any other planetary body this spectral range would be observed in reflectance. However for Venus we can obtain useful data only during nighttime using the thermal emission of the surface. So far no systematic studies have been done on the emissivity of Venus analog materials at high temperatures in this wavelength range due to the significant technical challenges of such experiments. At the Planetary Emissivity Laboratory (PEL) we started 6 years ago to extend our laboratory capabilities to support specifically missions to Venus and Mercury. Both planets exhibit surface temperatures up to 500°C and this extreme temperature range affects the spectral characteristics of the surface minerals. We are systematically studying different Venusian analogs to obtain spectra in the 1 microns region at Venus surface temperatures. First measurements of a carbonatite and an ijolite sample as analogs for low viscosity lavas clearly indicating changes of the emissivity signature at 1 micron with temperature. One of the next steps is to study tesserae analog materials to determine how the diagnostic the 1 micron region is for different compositions. We are currently developing a new instrument concept for future Venus missions designed specifically to observe Venus's surface in segments of the near-IR (NIR) spectrum that penetrate the atmosphere with minimal absorption. The Venus Emissivity Mapper (VEM) builds on experience from analysis of data from Galileo/NIMS, Cassini/VIMS, and especially VIRTIS on Venus Express. Unlike those general-purpose imaging spectrometers, VEM is a hyperspectral mapper focused on observing the surface. It will map the surface in five atmospheric windows between 0.85 and 1.18 microns. In addition, several other

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. Exploring Venus: Major scientific issues and directions

    NASA Astrophysics Data System (ADS)

    Esposito, Larry W.; Stofan, Ellen R.; Cravens, Thomas E.

    Venus has been a prime target of space exploration since the launch of Venera-1 in 1961. In 1962, Mariner 2 determined that the surface of Venus is hot, providing the first confirmation of its immense greenhouse effect. Venus has now been visited by numerous flybys, orbiters, atmospheric probes, landers, and balloons! Magellan's radar pierced the planet-encircling clouds to provide a global map of the Venus surface. Table 1 lists the chronology of Venus missions. Despite the numerous missions, the Venus environment provides a difficult target, and many significant questions remain unanswered. The state of current knowledge, the open questions, and ways to address them are discussed in the following chapters.

  20. 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

  1. 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.

  2. Electrophysiological characteristics of inhibitory neurons of the prepositus hypoglossi nucleus as analyzed in Venus-expressing transgenic rats.

    PubMed

    Shino, M; Kaneko, R; Yanagawa, Y; Kawaguchi, Y; Saito, Y

    2011-12-01

    The identification and characterization of excitatory and inhibitory neurons are significant steps in understanding neural network functions. In this study, we investigated the intrinsic electrophysiological properties of neurons in the prepositus hypoglossi nucleus (PHN), a brainstem structure that is involved in gaze holding, using whole-cell recordings in brainstem slices from vesicular GABA transporter (VGAT)-Venus transgenic rats, in which inhibitory neurons express the fluorescent protein Venus. To characterize the intrinsic properties of these neurons, we recorded afterhyperpolarization (AHP) profiles and firing patterns from Venus-expressing [Venus⁺] and Venus-non-expressing [Venus⁻] PHN neurons. Although both types of neurons showed a wide variety of AHP profiles and firing patterns, oscillatory firing was specific to Venus⁺ neurons, while a firing pattern showing only a few spikes was specific to Venus⁻ neurons. In addition, AHPs without a slow component and delayed spike generation were preferentially displayed by Venus⁺ neurons, whereas a firing pattern with constant interspike intervals was preferentially displayed by Venus⁻ neurons. We evaluated the mRNAs expression of glutamate decarboxylase (GAD65, GAD67) and glycine transporter 2 (GlyT2) to determine whether the recorded Venus⁺ neurons were GABAergic or glycinergic. Of the 67 Venus⁺ neurons tested, GlyT2 expression alone was detected in only one neuron. Approximately 40% (28/67) expressed GAD65 and/or GAD67 (GABAergic neuron), and the remainder (38/67) expressed both GAD(s) and GlyT2 (GABA&GLY neuron). These results suggest that most inhibitory PHN neurons use either GABA or both GABA and glycine as neurotransmitters. Although the overall distribution of firing patterns in GABAergic neurons was similar to that of GABA&GLY neurons, only GABA&GLY neurons exhibited a firing pattern with a long first interspike interval. These differential electrophysiological properties will be useful

  3. Entry at Venus

    NASA Technical Reports Server (NTRS)

    Venkatapathy, Ethiraj; Smith, Brandon

    2016-01-01

    This is lecture to be given at the IPPW 2016, as part of the 2 day course on Short Course on Destination Venus: Science, Technology and Mission Architectures. The attached presentation material is intended to be introduction to entry aspects of Venus in-situ robotic missions. The presentation introduces the audience to the aerodynamic and aerothermodynamic aspects as well as the loads, both aero and thermal, generated during entry. The course touches upon the system design aspects such as TPS design and both high and low ballistic coefficient entry system concepts that allow the science payload to be protected from the extreme entry environment and yet meet the mission objectives.

  4. 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.

  5. 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 cloudʼs 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 cloudʼs 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.

  6. 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.

  7. Space missions to Venus

    NASA Astrophysics Data System (ADS)

    Bertaux, J. L.

    1981-11-01

    Pioneer and Venera project achievements are summarized. The Venera spacecraft obtained temperature and pressure profiles down to the surface and measured the atmospheric bulk composition (CO2 96%, N2 4%). They took the first photographs of the surface showing rocks. They analyzed the surface, using a gamma ray spectrometer, and observed lightning. Mariner 10 took UV pictures of cloud cover, confirming the general 4 days rotation originally inferred from ground based observations. The surface was mapped by a radar altimeter.

  8. Detailed expression pattern of aldolase C (Aldoc) in the cerebellum, retina and other areas of the CNS studied in Aldoc-Venus knock-in mice.

    PubMed

    Fujita, Hirofumi; Aoki, Hanako; Ajioka, Itsuki; Yamazaki, Maya; Abe, Manabu; Oh-Nishi, Arata; Sakimura, Kenji; Sugihara, Izumi

    2014-01-01

    Aldolase C (Aldoc, also known as "zebrin II"), a brain type isozyme of a glycolysis enzyme, is expressed heterogeneously in subpopulations of cerebellar Purkinje cells (PCs) that are arranged longitudinally in a complex striped pattern in the cerebellar cortex, a pattern which is closely related to the topography of input and output axonal projections. Here, we generated knock-in Aldoc-Venus mice in which Aldoc expression is visualized by expression of a fluorescent protein, Venus. Since there was no obvious phenotypes in general brain morphology and in the striped pattern of the cerebellum in mutants, we made detailed observation of Aldoc expression pattern in the nervous system by using Venus expression in Aldoc-Venus heterozygotes. High levels of Venus expression were observed in cerebellar PCs, cartwheel cells in the dorsal cochlear nucleus, sensory epithelium of the inner ear and in all major types of retinal cells, while moderate levels of Venus expression were observed in astrocytes and satellite cells in the dorsal root ganglion. The striped arrangement of PCs that express Venus to different degrees was carefully traced with serial section alignment analysis and mapped on the unfolded scheme of the entire cerebellar cortex to re-identify all individual Aldoc stripes. A longitudinally striped boundary of Aldoc expression was first identified in the mouse flocculus, and was correlated with the climbing fiber projection pattern and expression of another compartmental marker molecule, heat shock protein 25 (HSP25). As in the rat, the cerebellar nuclei were divided into the rostrodorsal negative and the caudoventral positive portions by distinct projections of Aldoc-positive and negative PC axons in the mouse. Identification of the cerebellar Aldoc stripes in this study, as indicated in sample coronal and horizontal sections as well as in sample surface photos of whole-mount preparations, can be referred to in future experiments.

  9. Limb imaging of the Venus O2 visible nightglow with the Venus Monitoring Camera

    NASA Astrophysics Data System (ADS)

    GarcíA MuñOz, A.; Hueso, R.; SáNchez-Lavega, A.; Markiewicz, W. J.; Titov, D. V.; Witasse, O.; Opitz, A.

    2013-06-01

    investigated the Venus O2 visible nightglow with imagery from the Venus Monitoring Camera on Venus Express. Drawing from data collected between April 2007 and January 2011, we study the global distribution of this emission, discovered in the late 1970s by the Venera 9 and 10 missions. The inferred limb-viewing intensities are on the order of 150 kR at the lower latitudes and seem to drop somewhat toward the poles. The emission is generally stable, although there are episodes when the intensities rise up to 500 kR. We compare a set of Venus Monitoring Camera observations with coincident measurements of the O2 nightglow at 1.27 µm made with the Visible and Infrared Thermal Imaging Spectrometer, also on Venus Express. From the evidence gathered in this and past works, we suggest a direct correlation between the instantaneous emissions from the two O2 nightglow systems. Possible implications regarding the uncertain origin of the atomic oxygen green line at 557.7 nm are noted.

  10. 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.

  11. 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

  12. VIRTIS on Venus Express thermal emission spectra near 1μm

    NASA Astrophysics Data System (ADS)

    Mueller, Nils; Tsang, Constantine; Helbert, Joern; Smrekar, Suzanne; Piccioni, Giuseppe; Drossart, Pierre

    2016-10-01

    Thermal emission from the surface of Venus is observable through narrow spectral windows close to 1μm. Surface temperature is strongly constrained by surface elevation, due to the thick and dense atmosphere. The data from Visible and InfraRed Thermal Imaging Spectrometer VIRTIS on Venus Express together with altimetry constrain surface emissivity. In VIRTIS observations at 1.02μm, strongly deformed highland plateaus (tesserae) appear to have a lower emissivity consistent with continental crust, an interpretation that implies existence of an early ocean. Comparison between the Magellan stereo digital elevation model (DEM) and altimetry shows that the altimetry height error in rough tesserae greatly exceeds the formal error. In the one tesserae outlier covered by altimetry, DEM, and VIRTIS, the height error could account for the observed emissivity variation. The radiances observed at 1.10 and 1.18μm have a different response to topography, mostly due to spectrally varying absorption in the overlying atmospheric column. Thus if the tesserae have the same emissivity as volcanic plains, its spectrum should be the same as that of plains of the correct surface elevation. In order to investigate this statistically, we create a database of all long exposure duration VIRTIS spectra in the range of 1 – 1.4μm. The spectra are corrected for the ubiquitous straylight from the dayside, based on analysis of spectra showing deep space. Because the 1.10 and 1.18μm peaks are narrow compared to the variation of instrument spectral registration, we fit each spectrum with a synthetic spectrum from an atmospheric radiative transfer model, using wavelength offset and bandwidths as parameters in addition to atmospheric variables. This dataset of ~28 million thermal emission spectra spans a wide range of southern latitudes and night local times, and thus may be useful for studies beyond the question of surface emissivity. A portion of this research was conducted at the Jet

  13. 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.

  14. 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.

  15. Venus cartography

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  16. 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.

  17. Mariner Venus/Mercury 1973 navigation strategy

    NASA Technical Reports Server (NTRS)

    Mckinley, E. L.; Jones, J. B.; Bantell, M. H.

    1973-01-01

    This paper presents the navigational aspects of the Mariner Venus/Mercury 1973 mission. Principal emphasis is on the development of the trajectory correction strategy, propellant costs, and delivery accuracies at Venus and Mercury. Key error sources and mission constraints are discussed. Of particular interest are the statistics of the first, post-Venus, maneuver which must correct for the magnification of errors in the Venus encounter. Finally, although not a primary objective of the mission, the analysis is extended to include a second Mercury encounter.

  18. Planetary missions

    NASA Technical Reports Server (NTRS)

    Mclaughlin, William I.

    1989-01-01

    The scientific and engineering aspects of near-term missions for planetary exploration are outlined. The missions include the Voyager Neptune flyby, the Magellan survey of Venus, the Ocean Topography Experiment, the Mars Observer mission, the Galileo Jupiter Orbiter and Probe, the Comet Rendezvous Asteroid Flyby mission, the Mars Rover Sample Return mission, the Cassini mission to Saturn and Titan, and the Daedalus probe to Barnard's star. The spacecraft, scientific goals, and instruments for these missions are noted.

  19. Get the heat on - Obtaining high temperature emissivity measurements in support of the analysis of surface data from VIRTIS on VenusExpress

    NASA Astrophysics Data System (ADS)

    Müller, N.; Helbert, J. X.; Maturilli, A.; Piccioni, G.; Drossart, P.

    2008-12-01

    Analyzing the surface composition of Venus from remote-sensing measurements is a challenging task. Recently we have reported on brightness variations in the near infrared wavelength range observed with VIRTIS on VenusExpress. Our implication is that these brightness variations might be correlated to emissivity variations of the surface material. The next step to verify this hypothesis is to obtain data in the relevant spectral range at temperatures typical for the surface of Venus. We are currently developing a Planetary Emissivity Laboratory (PEL) at Deutsches Zentrum für Luft- und Rahmfahrt (DLR) in Berlin. The PEL allows measuring the emissivity of planetary analog materials grain sizes fractions from less than 25 microns all the way to bulk samples and at temperatures of more than 400°C, typically for the surface of Venus. The PEL development follows a multi-step approach. We are currently installing a new calibration target that will allow obtaining emissivity data on the full range from 1 to 50 microns with a usable signal-to-noise ratio. Here we will present first data in the range from 1 to 1.4 microns which covers the atmospheric windows used for the surface observations from VIRTIS on VenusExpress. We will focus especially on which measurements are necessary to verify our earlier hypotheses of compositional variations on the surface of Venus.

  20. 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.

  1. 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).

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. Transgenic frogs expressing the highly fluorescent protein venus under the control of a strong mammalian promoter suitable for monitoring living cells.

    PubMed

    Sakamaki, Kazuhiro; Takagi, Chiyo; Yoshino, Jun; Yokota, Hideo; Nakamura, Sakiko; Kominami, Katsuya; Hyodo, Akiko; Takamune, Kazufumi; Yuge, Masahiro; Ueno, Naoto

    2005-06-01

    To easily monitor living cells and organisms, we have created a transgenic Xenopus line expressing Venus, a brighter variant of yellow fluorescent protein, under the control of the CMV enhancer/chicken beta-actin (CAG) promoter. The established line exhibited high fluorescent intensity not only in most tissues of tadpoles to adult frogs but also in germ cells of both sexes, which enabled three-dimensional imaging of fluorescing organs from images of the serial slices of the transgenic animals. Furthermore, by using this transgenic line, we generated chimeric animals by brain implantation and importantly, we found that the brain grafts survived and expressed Venus in recipients after development, highlighting the boundary between fluorescent and nonfluorescent areas in live animals. Thus, Venus-expressing transgenic frogs, tadpoles, and embryos would facilitate their use in many applications, including the tracing of the fluorescent cells after tissue/organ transplantation.

  7. 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.

  8. 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.

  9. The characteristics of the O2 Herzberg II and Chamberlain bands observed with VIRTIS/Venus Express

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Piccioni, G.; Gérard, J. C.; Soret, L.; Slanger, T. G.; Politi, R.; Snels, M.; Drossart, P.; Nuccilli, F.

    2013-03-01

    The oxygen Venus nightglow emissions in the visible spectral range have been known since the early observations from the Venera spacecraft. Recent observations with the VIRTIS instrument on board Venus Express allowed us to re-examine the Herzberg II system of O2 and to further study its vertical distribution, in particular the (0-ν″ with ν″ = 7-13) bands. The present work describes the vertical profile of the observed bands and relative intensities from limb observation data. The wavelength-integrated intensities of the Herzberg II bands, with ν″ = 7-11, are inferred from the recorded spectra. The resulting values lie in the range of 84-116 kR at the altitudes of maximum intensity, which are found to lie in the range of 93-98 km. Three bands of the Chamberlain system, centered at 560 nm, 605 nm, and 657 nm have been identified as well. Their emission peak is located at about 100 km, 4 km higher than the Herzberg II bands. For the first time, the O2 nightglow emissions were investigated simultaneously in the visible and in the IR spectral range, showing a good agreement between the peak position for the Herzberg II and the O2(aΔg-XΣg-) bands. An airglow model, proposed by Gérard et al. (Gérard, J.C., Soret, L., Migliorini, A., Piccioni, G. [2013]. Icarus.) starting from realistic O and CO2 vertical distributions derived from Venus-Express observations, allows reproduction of the observed profiles for the three O2 systems.

  10. Abundance of unusual objects on the planet venus according to the data of missions of 1975-1982

    NASA Astrophysics Data System (ADS)

    Ksanfomality, L. V.

    2014-11-01

    The results of processing the archival data of the television experiment performed on the surface of the planet by the VENERA spacecraft in 1975 and 1982 are presented. In previously published papers, the author tried to show all diverse objects found by that time and their properties. In 2012-2014, new groups of objects have been found. This paper focuses on only one type of new finding (the conventional name is "hesperos") and their morphological features. It is shown that similar objects with dimensions from 13 to 25 cm, having the forms of a large fallen leaf or a spindle, are met in the regions of the planet Venus separated by distances of 900 and 4400 km.

  11. Venus within ESA probe reach

    NASA Astrophysics Data System (ADS)

    2006-03-01

    Venus Express mission controllers at the ESA Space Operations Centre (ESOC) in Darmstadt, Germany are making intensive preparations for orbit insertion. This comprises a series of telecommands, engine burns and manoeuvres designed to slow the spacecraft down from a velocity of 29000 km per hour relative to Venus, just before the first burn, to an entry velocity some 15% slower, allowing the probe to be captured into orbit around the planet. The spacecraft will have to ignite its main engine for 50 minutes in order to achieve deceleration and place itself into a highly elliptical orbit around the planet. Most of its 570 kg of onboard propellant will be used for this manoeuvre. The spacecraft’s solar arrays will be positioned so as to reduce the possibility of excessive mechanical load during engine ignition. Over the subsequent days, a series of additional burns will be done to lower the orbit apocentre and to control the pericentre. The aim is to end up in a 24-hour orbit around Venus early in May. The Venus orbit injection operations can be followed live at ESA establishments, with ESOC acting as focal point of interest (see attached programme). In all establishments, ESA specialists will be on hand for interviews. ESA TV will cover this event live from ESOC in Darmstadt. The live transmission will be carried free-to-air. For broadcasters, complete details of the various satellite feeds are listed at http://television.esa.int. The event will be covered on the web at venus.esa.int. The website will feature regular updates, including video coverage of the press conference and podcast from the control room at ESA’s Operations Centre. Media representatives wishing to follow the event at one of the ESA establishments listed below are requested to fill in the attached registration form and fax it back to the place of their choice. For further information, please contact: ESA Media Relations Division Tel : +33(0)1.53.69.7155 Fax: +33(0)1.53.69.7690 Venus Express

  12. 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

  13. 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

  14. 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.

  15. 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

  16. Small Scale Waves on Venus at High Latitudes

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay; Markiewicz, W. J.; Moissl, R.; Titov, D.

    2008-09-01

    On many occasions, the Venus Monitoring Camera (VMC) on Venus Express has observed several small scale waves or wave trains in high northern latitudes ( 70 to 75°) of Venus for the first time. Such waves were not detected earlier due to a combination of spatial resolution, observed region and duration. Wave trains with different characteristics have been seen at all four wavelengths used by the VMC (centered at 365, 513. 935 and 1010nm with 40, 50, 70 and 20 nm) in and are consistently in the same area on multiple consecutive orbits. Many are similar in appearance to ripples with wavelengths 5 to10 km with extents of some tens of km while others appear as thin straight lines, similar to the Circum Equatorial Belts (CEB) seen previously from Mariner 10 and Pioneer Venus missions at low latitudes. These are distinct from the fine scale transverse waves on the spiral bands on Venus which have been observed by both the VMC and the Visible Infrared Thermal Imaging Spectrometer (VIRTIS). In appearance and perhaps origins, these wave trains appear to be similar to gravity waves observed on Earth, particularly in the airglow images. Their detection on Venus confirms the existence of an atmospheric layer with a very stable lapse rate seen in the thermal structure data at an altitude of 65 to 67 km. The triggering mechanism for these waves could be horizontal or vertical wind shear. The contribution of these waves to momentum transport is not known, but likely is insignificant. However, this could be an observational limitation due to the combination of the eccentric orbit of Venus Express and the camera capabilities. This work has been made possible from a NASA Participating Scientist Grant NNG06GC68G and with the support provided by the VMC Team.

  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. 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.

  19. Multiple signal propagation at the tropopause of the Venusian atmosphere: new insights from the Radio Science Experiment (VeRa) onboard Venus Express

    NASA Astrophysics Data System (ADS)

    Herrmann, Maren; Oschlisniok, Janusz; Remus, Stefan; Tellmann, Silvia; Häusler, Bernd; Pätzold, Martin

    2016-10-01

    The rapid change of the refractive index over a short altitude range in a planetary atmosphere can lead to multi-path effects when sounding the atmosphere with radio waves. The Radio Science Experiment (VeRa) [1,2] onboard Venus Express sounded the Venusian atmosphere from 90 km downward to 40 km altitude[3,4]. More than 800 profiles of temperature, pressure and neutral number density could be retrieved which cover almost all local times and latitudes. A specially developed analysis method based on the VeRa open loop receiving technique deciphers the multi-path effect and identifies an inversion layer near the tropopause at an altitude of about 60km. This layer is of particular interest - it separates the stratified troposphere from the highly variable mesosphere and can be a likely location for the formation of gravity waves [5]. The new retrieval method shows an inversion layer up to 15 K colder than commonly thought. Local time and latitude dependence including the influence of the spacecraft trajectory on this effect will be discussed. These results will contribute to a consistent picture of the Venus' thermal atmosphere structure and therefore help to improve atmospheric models.[1] Häusler, B. et al: 'Radio science investigations by VeRa onboard the Venus Express spacecraft' Planetary and Space Science 54, 2006[2] Häusler, B. et al, 'Venus Atmospheric, Ionospheric, Surface and Interplanetery Radio-Wave Propagation Studies with the VeRa Radio Science experiment' Eur. Space Agencys, Spec. Publ., ESA SP 1295, 2007[3] Pätzold, M. et al: 'The structure of Venus' middle atmosphere and ionosphere', Nature 450, 2007[4] Tellmann, S. et al : 'Structure of the Venus neutral atmosphere as observed by the Radio Science experiment VeRa on Venus Express', Journal of Geophysical Research 114, 2009[5] Tellmann, S. et al: 'Small-scale temperature fluctuations seen by the VeRa Radio Science Experiment on Venus Express' Icarus 221, 2012.

  20. 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.

  1. [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

  2. 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.

  3. 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.

  4. 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.

  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. 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.

  7. 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.

  8. TheRadio Science Experiment VeRa onboard ESA's Venus Express (VEX) Spacecraft

    NASA Astrophysics Data System (ADS)

    Haeusler, Bernd; Paetzold, M.; Bird, M. K.; Simpson, R. A.; Tyler, L. G.; Dehant, V.; Imamura, T.; Tellmann, S.; Mattei, R.

    2006-09-01

    The VEX spacecraft was successfully injected into the Venus orbit on April 11, 2006. VeRa is an active radio sounding instrument which will measure atmospheric/ionospheric temperature and density profiles, sound with bistatic radar experiments the surface of the planet, will measure its gravity anomalies and investigate also the structure of the corona by analyzing radio carrier signals received on ground in the S- and X-frequency bands. The radio science instrument VeRa is equipped with an ultrastable oscillator (USO) which will be used especially for atmospheric sounding and bistatic radar experiments as frequency reference in the OneWay transmission mode. We will present the current status of the experiment, the results of the commissioning tests and first scientific results.

  9. 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.

  10. 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)

  11. 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)

  12. 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.

  13. Towards a Self Consistent Model of the Thermal Structure of the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Limaye, Sanjay; Vandaele, Ann C.; Wilson, Colin

    Nearly three decades ago, an international effort led to the adoption of the Venus International Reference Atmosphere (VIRA) was published in 1985 after the significant data returned by the Pioneer Venus Orbiter and Probes and the earlier Venera missions (Kliore et al., 1985). The vertical thermal structure is one component of the reference model which relied primarily on the three Pioneer Venus Small Probes, the Large Probe profiles as well as several hundred retrieved temperature profiles from the Pioneer Venus Orbiter radio occultation data collected during 1978 - 1982. Since then a huge amount of thermal structure data has been obtained from multiple instruments on ESA’s Venus Express (VEX) orbiter mission. The VEX data come from retrieval of temperature profiles from SPICAV/SOIR stellar/solar occultations, VeRa radio occultations and from the passive remote sensing by the VIRTIS instrument. The results of these three experiments vary in their intrinsic properties - altitude coverage, spatial and temporal sampling and resolution and accuracy An international team has been formed with support from the International Space Studies Institute (Bern, Switzerland) to consider the observations of the Venus atmospheric structure obtained since the data used for the COSPAR Venus International Reference Atmosphere (Kliore et al., 1985). We report on the progress made by the comparison of the newer data with VIRA model and also between different experiments where there is overlap. Kliore, A.J., V.I. Moroz, and G.M. Keating, Eds. 1985, VIRA: Venus International Reference Atmosphere, Advances in Space Research, Volume 5, Number 11, 307 pages.

  14. 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.

  15. 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.

  16. 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

  17. 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...

  18. 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 ...

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  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. 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

  7. 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

  8. The main layers of the ionosphere of Venus as seen by Pioneer Venus Orbiter radio occultations

    NASA Astrophysics Data System (ADS)

    Hermann, Jacob; Withers, Paul; Vogt, Marissa F.

    2016-10-01

    Pioneer Venus Orbiter (PVO) performed numerous atmospheric experiments from 1978 to 1992. Radio occultation measurements were used to create vertical ionospheric electron density profiles extending as low as 100 km altitude; yielding data coverage across the V1 and V2 layers of the Venusian ionosphere, 125 and 140 km respectively. The PVO data give us a unique look at the ionosphere during solar maximum compared to later Venus missions. However, none of these ionospheric profiles were archived at the PDS nor have been available for comparison to Venus Express observations. We have extracted 120 PVO radio occultation profiles from published papers using a program to digitally read data from graphical images. Additionally, the NSSDC had 94 profiles, 63 of which were added to our dataset. The data from both sources were used in conjunction to analyze trends between solar activity and the characteristics of the V1 and V2 layers. The V1 layer, created by soft x-rays, should react more to changes in solar activity than the EUV created V2 layer. We intend to archive this data at the PDS so that the community can easily access digital measurements of the Venusian ionosphere at solar maximum.

  9. 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

  10. The Venus environment

    SciTech Connect

    Not Available

    1982-08-01

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

  11. Reference atmospheres: VIRA II -Venus International Reference Atmosphere update.

    NASA Astrophysics Data System (ADS)

    Zasova, Ludmila

    2012-07-01

    VIRA I was started in 1982 (30 years ago) and published in1985 (ASR,v5,n11, 1985) by G. Keating, A. Kliore, and V. Moroz. The purpose was to produce a concise, descriptive model summarizing the physical properties of the atmosphere of Venus, which by then had been extensively observed by instruments on board the Venera and Pioneer space probes. VIRA was used by many scientists and engineers in their studies as referent standard of atmospheric data. Afterwards several missions have obtained new data. In particular the experiments on late Veneras and Venus Express. Experiments on board of VEX, working on the orbit for 6 years, provide new high quality data on atmospheric structure, clouds properties, dynamics, composition of the atmosphere, thermal balance, ionosphere. These new data will be used for VIRA update. Original data consists of 7 Chapters.(1 ) Models of the structure of the atmosphere of Venus from the surface to 100 km altitude, (2) Circulation of the atmosphere from surface to 100 km, (3) Particulate matter in the Venus atmosphere, (4) Models of Venus neutral upper atmosphere: structure and composition, (5) Composition of the atmosphere below 100 km altitude, (6) Solar and thermal radiation in the Venus atmosphere, (7) The Venus ionosphere. By 2002 Gerry Keating collected materials to update VIRA. But only two chapter were published: (1 ) Models of the structure of the atmosphere of Venus from the surface to 100 km altitude (Zasova et al, 2006, Cosmic Research, 44, N4), (5) Composition of the atmosphere below 100 km altitude (De Bergh et al. 2006, PSS). Both these chapters were based on the data, obtained before VEX. At the moment the structure of the original VIRA looks acceptable for VIRA II also, however, new Chapters may be added. At COSPAR 2014 in Moscow the session on Reference atmospheres (RAPS), may be proposed to continue discussion on VIRA, and start working on MIRA, and complete VIRA and publish (including CD) after COSPAR 2016 (or may be even

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

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

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

    PubMed Central

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

    2016-01-01

    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. PMID:27009234

  14. 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.

  15. 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.

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

    PubMed

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

    2016-01-01

    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. PMID:27009234

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

    PubMed

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

    2016-03-24

    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.

  18. Search for ongoing volcanic activity on Venus

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  19. Pioneer Venus orbiter electron temperature probe

    NASA Technical Reports Server (NTRS)

    Brace, Larry H.

    1994-01-01

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

  20. Venus mapping

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  1. Scientists Identify Exploration Goals for Venus

    NASA Astrophysics Data System (ADS)

    Kumar, Mohi

    2014-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  3. Hypothetical flora and fauna of Venus

    NASA Astrophysics Data System (ADS)

    Ksanfomality, L. V.

    2014-12-01

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

  4. Interplanetary mission planning

    NASA Technical Reports Server (NTRS)

    1971-01-01

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

  5. Hot Flow Anomalies at Venus

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  6. Scientific Balloons for Venus Exploration

    NASA Astrophysics Data System (ADS)

    Cutts, James; Yavrouian, Andre; Nott, Julian; Baines, Kevin; Limaye, Sanjay; Wilson, Colin; Kerzhanovich, Viktor; Voss, Paul; Hall, Jeffery

    Almost 30 years ago, two balloons were successfully deployed into the atmosphere of Venus as an element of the VeGa - Venus Halley mission conducted by the Soviet Union. As interest in further Venus exploration grows among the established planetary exploration agencies - in Europe, Japan, Russia and the United States, use of balloons is emerging as an essential part of that investigative program. Venus balloons have been proposed in NASA’s Discovery program and ESA’s cosmic vision program and are a key element in NASA’s strategic plan for Venus exploration. At JPL, the focus for the last decade has been on the development of a 7m diameter superpressure pressure(twice that of VeGa) capable of carrying a 100 kg payload (14 times that of VeGA balloons), operating for more than 30 days (15 times the 2 day flight duration of the VeGa balloons) and transmitting up to 20 Mbit of data (300 times that of VeGa balloons). This new generation of balloons must tolerate day night transitions on Venus as well as extended exposure to the sulfuric acid environment. These constant altitude balloons operating at an altitude of about 55 km on Venus where temperatures are benign can also deploy sondes to sound the atmosphere beneath the probe and deliver deep sondes equipped to survive and operate down to the surface. The technology for these balloons is now maturing rapidly and we are now looking forward to the prospects for altitude control balloons that can cycle repeatedly through the Venus cloud region. One concept, which has been used for tropospheric profiling in Antarctica, is the pumped-helium balloon, with heritage to the anchor balloon, and would be best adapted for flight above the 55 km level. Phase change balloons, which use the atmosphere as a heat engine, can be used to investigate the lower cloud region down to 30 km. Progress in components for high temperature operation may also enable investigation of the deep atmosphere of Venus with metal-based balloons.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  8. Venus Highland Anomalous Reflectivity

    NASA Astrophysics Data System (ADS)

    Simpson, Richard A.; Tyler, G. L.; Häusler, B.; Mattei, R.; Patzold, M.

    2009-09-01

    Maxwell Montes was one of several unusually bright areas identified from early Venus radar backscatter observations. Pioneer Venus' orbiting radar associated low emissivity with the bright areas and established a correlation between reflectivity and altitude. Magellan, using an oblique bistatic geometry, showed that the bright surface dielectric constant was not only large but also imaginary -- i.e., the material was conducting, at least near Cleopatra Patera (Pettengill et al., Science, 272, 1996). Venus Express (VEX) repeated Magellan's bistatic observations over Maxwell, using the more conventional circular polarization carried by most spacecraft. Although VEX signal-to-noise ratio was lower than Magellan's, echoes were sufficiently strong to verify the Magellan conclusions near Cleopatra (see J. Geophys. Res., 114, E00B41, doi:10.1029/2008JE003156). Only about 40% of the surface at Cleopatra scatters specularly, opening the Fresnel (specular) interpretation model to question. Elsewhere in Maxwell, the specular percentage may be even lower. Nonetheless, the echo polarization is reversed throughout Maxwell, a result that is consistent with large dielectric constants and difficult to explain without resorting qualitatively (if not quantitatively) to specular models. VEX was scheduled to explore other high altitude regions when its S-Band (13-cm wavelength) radio system failed in late 2006, so further probing of high altitude targets awaits arrival of a new spacecraft.

  9. Dayside thermal structure of Venus' upper atmosphere characterized by a global model

    NASA Astrophysics Data System (ADS)

    Brecht, A. S.; Bougher, S. W.

    2012-08-01

    Observations of Venus' dayside thermal structure are being conducted through ground based observatories. These temperature measurements, along with those from several instruments onboard the current Venus Express mission, are augmenting the previous thermal structure data from past missions (e.g., Veneras', Pioneer Venus Orbiter, Pioneer Venus Probes). These recent ground-based and VEx observations reveal the Venus dayside lower thermosphere to be considerably warmer and dynamically important than previously understood. In this study, a three dimensional general circulation model, the Venus Thermospheric General Circulation Model (VTGCM), is used to provide dayside temperature predictions for comparison to these recent ground based observations. Such a comparison serves to identify and quantify the underlying thermal processes responsible for the observed dayside temperature structure. The VTGCM reproduces the dayside temperatures observed near 110 km at noon from 40°S to 40°N very well. In addition, the global winds generated by these warm dayside temperatures are shown to give rise to dayside upwelling (divergence) and nightside subsidence (convergence) resulting in nightside warming near the anti-solar point at ˜104 km. Corresponding nightside temperatures reach ˜198 K, in accord with averaged measurements. This agreement implies (1) it is important for GCMs to include the updated radiative heating and cooling rates presented in Roldán et al. (2000) and (2) the current VTS3 and VIRA empirical models are in-sufficient in representing the warm regions observed in the thermal structure of the dayside lower thermosphere (˜100 to 130 km) and need to be updated.

  10. The Plains of Venus

    NASA Astrophysics Data System (ADS)

    Sharpton, V. L.

    2013-12-01

    extremely fluid flows (i.e., channel formers), to viscous, possibly felsic lavas of steep-sided domes. Wrinkle ridges deform many plains units and this has been taken to indicate that these ridges essentially form an early stratigraphic marker that limits subsequent volcanism to a minimum. However, subtle backscatter variations within many ridged plains units suggest (but do not prove) that some plains volcanism continued well after local ridge deformation ended. Furthermore, many of volcanic sources show little, if any, indications of tectonic modification and detailed analyses have concluded that resurfacing rates could be similar to those on Earth. Improving constraints on the rates and styles of volcanism within the plains could lend valuable insights into the evolution of Venus's internal heat budget and the transition from thin-lid to thick-lid tectonic regimes. Improved spatial and radiometric resolution of radar images would greatly improve abilities to construct the complex local stratigraphy of ridged plains. Constraining the resurfacing history of Venus is central to understanding how Earth-sized planets evolve and whether or not their evolutionary pathways lead to habitability. This goal can only be adequately addressed if broad coverage is added to the implementation strategies of any future mapping missions to Venus.

  11. Venus: Water and Life

    NASA Astrophysics Data System (ADS)

    Ditkof, J. F.

    2013-05-01

    Amphiboles that contain the hydroxide ion form only in the presence of water and this fact has become the way for scientists to prove that Venus was once a water world. Though, tremolite is considered the main mineral to look for, it requires life that is analogous to the ancient life here on Earth for it to form. Dolomite is the main ingredient for the formation of this low grade metamorphic mineral and without it would be very difficult for tremolite to form, unless there is another process that is unknown to science. Venus is known to have extensive volcanic features (over 1600 confirmed shield volcanoes dot its surface) and with little erosion taking place; a mineral that is associated with volcanism and forms only in the presence of water should be regarded as the main goal. Hornblende can form via volcanism or a metamorphic process but requires water for initial formation. The European Space Agency is currently trying to determine whether or not the continents on Venus' surface are made of granite, as they argue granite requires water for formation. Either way, computer models suggest that any oceans that formed on the surface would have lasted at best 2 billion years, as the surface is estimated to be only 800 million years old, any hornblende that would have formed is more than likely going to be deep underground. To find this mineral, as well as others, it would require a mission that has the ability to drill into the surface, as the easiest place to do this would be on the mountain peaks in the Northern Hemisphere on the Ishtar Terra continent. Through the process of uplift, any remaining hornblende may have been exposed or very near exposed to the surface. Do to the amount of fluorine in the atmosphere and the interaction between this and the lithosphere, the hydroxyl ions may have been replaced with fluorine turning the hornblende into the more stable fluoro-hornblende. To further add to the mystery of Venus is the unusual atmospheric composition. The

  12. Venus - False Color Image of Alpha Regio

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This Magellan radar image shows Alpha Regio, a topographic upland approximately 1,300 kilometers (806 miles) across which is centered on 25 degrees south latitude, 4 degrees east longitude. In 1963 Alpha Regio was the first feature on Venus to be identified from Earth based radar. The radar bright area of Alpha Regio is characterized by multiple sets of intersecting trends of structural features such as ridges, troughs and flat floored fault valleys that together form a polygonal outline. Circular to oblong dark patches within the complex terrain are local topographic lows that are filled with smooth volcanic lava. Complex ridged terrains such as Alpha, formerly called 'tessera' in the Soviet Venera 15 and 16 radar missions and the Arecibo radar data, appear to be widespread and common surface expressions of Venusian tectonic processes. Directly south of the complex ridged terrain is a large ovoid shaped feature named Eve. The radar bright spot located centrally within Eve marks the location of the prime meridian of Venus. Magellan radar data reveals that relatively young lava flows emanate from Eve and extends into the southern margin of the ridged terrain at Alpha. The mosaic was produced by Eric de Jong and Myche McAuley in the JPL Multimission Image Processing Laboratory.

  13. Measurements Needed to Understand Superrotation and Circulation in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Parish, H. F.; Schubert, G.; Covey, C. C.

    2013-12-01

    An understanding of the dynamics of Venus' atmosphere is a high priority in future Venus research (VEXAG and the Planetary Science Decadal Survey). Venus' atmosphere is characterized by strong superrotation, in which the winds at cloud heights reach velocities over 100 m/s, around 60 times faster than the surface rotation rate. When realistic background conditions are applied, numerical models simulate cloud level superrotation with wind magnitudes smaller than the largest winds observed. In addition, no model to date has been able to generate superrotating winds in the dense atmosphere between the surface and the clouds with magnitudes comparable to those measured in situ; hence the vertically integrated atmospheric angular momentum in models is far less than observed. One obstacle to realistically modeling the atmosphere below the cloud level and understanding how angular momentum is transported from the surface to the cloud level is the scarcity of observations in Venus' lower atmosphere. The only wind profiles in the 0 to ˜40 km altitude range come from a few entry probes on the Pioneer Venus and Venera missions. Interplanetary trajectories under minimum-energy constraints largely confined these probes to low latitudes between midnight and early afternoon and measurements only covered the limited time intervals for each probe to fall to the surface. Simulated lower atmosphere winds may be sensitive to the parameterization of surface-atmosphere interactions, but the values of relevant parameters cannot currently be measured. In spite of the apparent symmetry of Venus' orbit and the lack of significant seasons, variability in space and time is also found to be an important feature of Venus' atmosphere. Periodicities with timescales of several years are found in observations of zonal winds, temperatures and composition, for example, in Pioneer Venus measurements of cloud top winds, ground based observations of CO and temperature, and measurements of SO2 taken by

  14. Solar Powered Flight on Venus

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony; Landis, Geoff (Technical Monitor)

    2004-01-01

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

  15. Preliminary results of the pioneer venus nephelometer experiment.

    PubMed

    Ragent, B; Blamont, J

    1979-02-23

    Preliminary results of the nephelometer experiments conducted aboard the large sounder, day, north, and night probes of the Pioneer Venus mission are presented. The vertical structures of the Venus clouds observed simultaneously at each of the four locations from altitudes of from 63 kilometers to the surface are compared, and similarities and differences are noted. Tentative results from attempting to use the data from the nephelometer and cloud particle size spectrometer on the sounder probe to identify the indices of refraction of cloud particles in various regions of the Venus clouds are reported. Finally the nephelometer readings for the day probe during impact on the surface of Venus are presented.

  16. Atmospheric tides on Venus. III - The planetary boundary layer

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, A. R.

    1983-10-01

    Diurnal solar heating of Venus' surface produces variable temperatures, winds, and pressure gradients within a shallow layer at the bottom of the atmosphere. The corresponding asymmetric mass distribution experiences a tidal torque tending to maintain Venus' slow retrograde rotation. It is shown that including viscosity in the boundary layer does not materially affect the balance of torques. On the other hand, friction between the air and ground can reduce the predicted wind speeds from about 5 to about 1 m/sec in the lower atmosphere, more consistent with the observations from Venus landers and descent probes. Implications for aeolian activity on Venus' surface and for future missions are discussed.

  17. Pioneer Venus multiprobe entry telemetry recovery

    NASA Technical Reports Server (NTRS)

    Miller, R. B.; Ramos, R.

    1980-01-01

    The entry phase of the Pioneer Venus Multiprobe Mission involved data transmission over a two hour span. The criticality of recovering those two hours of data, coupled with the fact that there were no radio signals from the probes until their arrival at Venus, dictated unique telemetry recovery approaches on the ground. The result was double redundancy, use of spectrum analyzers to aid in rapid acquisition of the signals, and development of a technique for recovery of telemetry data without the use of real time coherent detection, which is normally employed for all other planetary missions.

  18. High Temperature, Wireless Seismometer Sensor for Venus

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

    McGouldrick, Kevin; Tsang, Constantine C. C.

    2015-11-01

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

  20. New measurements of Venus winds with ground-based Doppler velocimetry at CFHT

    NASA Astrophysics Data System (ADS)

    Machado, P.; Widemann, T.; Luz, D.; Peralta, J.; Berry, D. L.

    2012-04-01

    measurements made with the VMC camera onboard the Venus Express. We will present first results from this work, comparing with previous results by the CFHT/ESPaDOnS and VLT-UVES spectrographs (Machado et al., 2012), with Galileo fly-by measurements and with VEx nominal mission observations (Peralta et al., 2007, Luz et al., 2011). Acknowledgements: The authors acknowledge support from FCT through projects PTDC/CTE-AST/110702/2009 and PEst-OE/FIS/UI2751/2011. PM and TW also acknowledge support from the Observatoire de Paris. Lellouch, E., and Witasse, O., A coordinated campaign of Venus ground-based observations and Venus Express measurements, Planetary and Space Science 56 (2008) 1317-1319. Luz, D., et al., Venus's polar vortex reveals precessing circulation, Science 332 (2011) 577-580. Machado, P., Luz, D. Widemann, T., Lellouch, E., Witasse, O, Characterizing the atmospheric dynamics of Venus from ground-based Doppler velocimetry, Icarus, submitted. Peralta J., R. Hueso, A. Sánchez-Lavega, A reanalysis of Venus winds at two cloud levels from Galileo SSI images, Icarus 190 (2007) 469-477. Widemann, T., Lellouch, E., Donati, J.-F., 2008, Venus Doppler winds at Cloud Tops Observed with ESPaDOnS at CFHT, Planetary and Space Science, 56, 1320-1334.

  1. Zephyr: A Landsailing Rover for Venus

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  2. Evidence for Long-term Variability at Venus' Clouds Top

    NASA Astrophysics Data System (ADS)

    Marcq, E.; Bertaux, J. L.; Montmessin, F.; Belyaev, D.

    2012-09-01

    The ESA mission Venus Express has been operating since 2006 around Venus, thus providing a dataset spanning more than six years of observations. Following the methods used by Marcq et al. [1], we have thus derived (i) SO2 column densities above cloud top and (ii) mean UV brightness in the 200-320 nm range between 2006/04/14 and 2012/02/18. Very strong temporal and spatial variability is found for both observable parameters, but a mean decrease is found for SO2 (5 to 10-fold) and mean UV brightness (about 40%) between 2007 and 2012. The latitudinal pattern is also subject to changes, with decreasing SO2 with increasing latitude prevalent during SO2-rich periods and no noticeable (or even reversed) latitudinal gradient during SO2-poor episods. This evolution is highly reminiscent of the situation observed by Pioneer Venus and Venera-15 [2, 3]. Possible causes for these long-term trends are difficult to assess at the present stage of our study. Fluctuation on a decadal timescale of the intensity of the advection from the deep, SO2-enriched atmosphere is the most likely candidate according to simple modeling, but it does not preclude possible fluctuations in the volume of volcanic outgassing rich in SO2.

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  4. High Temperature Mechanisms for Venus Exploration

    NASA Astrophysics Data System (ADS)

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

    Future Venus missions, including New Frontiers Venus In-Situ Explorer and three Flagship Missions - Venus Geophysical Network, Venus Mobile Explorer and Venus Surface Sample Return all focus on searching for evidence of past climate change both on the surface and in the atmospheric composition as well as in the interior dynamics of the planet. In order to achieve these goals and objectives, many key technologies need to be developed for the Venus extreme environment. These key technologies include sample acquisition systems and other high-temperature mechanisms and mobility systems capable of extended operation when directly exposed to the Venus surface or lower atmosphere environment. Honeybee Robotics has developed two types of high temperature motors, the materials and components in both motors were selected based on the requirement to survive temperatures above a minimum of 460° C, at earth atmosphere. The prototype Switched Reluctance Motor (SRM) has been operated non-continuously for over 20 hours at Venus-like conditions (460° C temperature, mostly CO2 gas environment) and it remains functional. A drilling system, actuated by two SRMs was tested in Venus-like conditions, 460° C temperature and mostly CO2 gas environment, for more than 15 hours. The drill successfully completed three tests by drilling into chalk up to 6 inches deep in each test. A first generation Brushless DC (BLDC) Motor and high temperature resolver were also tested and the feasibility of the designs was demonstrated by the extended operation of both devices under Venus-like condition. Further development of the BLDC motor and resolver continues and these devices will, ultimately, be integrated into the development of a high temperature sample acquisition scoop and high temperature joint (awarded SBIR Phase II in October, 2007). Both the SR and BLDC motors will undergo extensive testing at Venus temperature and pressure (TRL6) and are expected to be mission ready before the next New

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

    NASA Astrophysics Data System (ADS)

    Cardesín Moinelo, Alejandro

    2010-04-01

    This PhD Thesis describes the activities performed during the Research Program undertaken for two years at the Istituto Nazionale di AstroFisica in Rome, Italy, as active member of the VIRTIS Technical and Scientific Team, and one additional year at the European Space Astronomy Center in Madrid, Spain, as member of the Mars Express Science Ground Segment. This document will show a study of all sections of the Science Ground Segment of the Venus Express mission, from the planning of the scientific operations, to the generation, calibration and archiving of the science data, including the production of valuable high level products. We will present and discuss here the end-to-end diagram of the ground segment from the technical and scientific point of view, in order to describe the overall flow of information: from the original scientific requests of the principal investigator and interdisciplinary teams, up to the spacecraft, and down again for the analysis of the measurements and interpretation of the scientific results. These scientific results drive to new and more elaborated scientific requests, which are used as feedback to the planning cycle, closing the circle. Special attention is given here to describe the implementation and development of the data pipeline for the VIRTIS instrument onboard Venus Express. During the research program, both the raw data generation pipeline and the data calibration pipeline were developed and automated in order to produce the final raw and calibrated data products from the input telemetry of the instrument. The final raw and calibrated products presented in this work are currently being used by the VIRTIS Science team for data analysis and are distributed to the whole scientific community via the Planetary Science Archive. More than 20,000 raw data files and 10,000 calibrated products have already been generated after almost 4 years of mission. In the final part of the Thesis, we will also present some high level data

  6. Venus Aerobot Surface Science Imaging System (VASSIS)

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald

    1999-01-01

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

  7. Venus Climate Sensitivity

    NASA Astrophysics Data System (ADS)

    Bullock, M.

    2012-12-01

    The sensitivity of the Earth's climate to changes in atmospheric carbon dioxide is often expressed as the net change in radiative forcing, in W/m2, due to a doubling of carbon dioxide concentration. Feedbacks due to consequent changes in water vapor abundance, clouds, and surface ice act to magnify or suppress the net change in radiative forcing due to doubling of atmospheric carbon dioxide. For example, for the net change in radiative energy balance of ΔH is ΔH=∂F/∂[CO2 ] Δ[CO2] + ∂F/∂T ΔT + ∂F/∂[H2O] ∂[H2O]/∂T ΔT + So/4 ∂α/∂T ΔT where F is the flux at the top of the atmosphere, [CO2] and [H2O] are the concentrations of carbon dioxide and water vapor in the atmosphere, So is the solar flux, and α is the planetary albedo. The first term on the right is the direct effect of atmospheric carbon dioxide concentration on the outgoing thermal flux. The second term represents the adjustment to outgoing flux that results solely from changes in atmospheric temperature. The third term is the water vapor greenhouse term, and the fourth is the response the Earth's albedo to changes in temperature. Radiative balance is established when ΔH --> 0. The sensitivity of Venus' climate due to perturbations in atmospheric constituents can be expressed in a similar manner. This analysis is useful for assessing the changes in surface temperature that result from volcanic activity, and the long term effects of the loss of volatiles to space or to reactions with the surface. I will discuss the change in radiative forcing of Venus' climate due to alteration of atmospheric water vapor abundance. As with carbon dioxide in the Earth's atmosphere, changes in Venus' atmospheric water vapor have both direct and indirect climate forcing effects. The analogous linearized climate sensitivity equation for Venus will be discussed, with an emphasis on the nature of the feedback each term represents.

  8. Studying Venus' atmosphere and ionosphere with Planetary Radio Interferometry and Doppler Experiment (PRIDE)

    NASA Astrophysics Data System (ADS)

    Bocanegra-Bahamon, T. M.; Cimo, G.; Duev, D. A.; Gurvits, L. I.; Marty, J. Ch.; Pogrebenko, S. V.; Rosenblatt, P.

    2014-04-01

    The Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a technique that can provide a multi-disciplinary enhancement of the science return of planetary missions. By performing precise Doppler tracking of a spacecraft carrier radio signal, at Earth-based radio telescopes, and VLBI-style processing of these signals in phase-referencing mode, the technique allows the determination of the radial velocity and lateral coordinates of the spacecraft with very high accuracy[1]. Because of the accurate examination of the changes in phase and amplitude of the radio signal propagating from the spacecraft to the multiple stations on Earth, the PRIDE technique can be used for several fields of planetary research. The application of this technique for atmospheric studies has been assessed by observing ESA's Venus Express (VEX) during Venus occultation events in 2012 and 2014, and by participating in one of the Venus Express Atmospheric Drag Experiment (VExADE) campaigns in 2012. Both studies are contributing to the characterization efforts of the atmosphere and ionosphere of Venus. During the Venus Express Atmospheric Drag Experiment (VExADE) campaigns VEX's orbit pericenter was lowered into an altitude range of approximately 165 to 175 km in order to probe Venus upper atmosphere above its north pole. The first VExADE campaigns were carried out between 2009-2010 using Doppler tracking data acquired by the VEX radio science experiment (VeRa), which provided the first in situ measurements of the density of Venus' polar thermosphere at solar minimum conditions [2]. In the December 2012 campaign the PRIDE-team participated by tracking VEX with several radio telescopes from the European VLBI Network (EVN) during pericenter passage. A Doppler frequency drop of ∼40 mHz was detected as VEX reached the lowest altitudes at around 170 km. The tracking data for each pericenter pass is fitted for precise orbit determination, from which drag acceleration estimates and the

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

    NASA Technical Reports Server (NTRS)

    1973-01-01

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

  10. The Importance of Venus Lightning Investigations

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Lightning in planetary atmospheres arises due to the separation of electric charges in convective cloud systems. We expect that Venus should have strong thermally driven winds at its location of 0.72 AU from the Sun. Observations of the cloud tops and the vertical motions of the atmosphere by the VEGA balloons confirm this expectation. We have made extensive surveys for lightning on Venus with spacecraft in the Venusian ionosphere. However, as yet we do not have a complete mapping of the occurrence of lightning because at the low frequencies at which measurements have been made it is difficult for the waves generated to penetrate the ionosphere. We expect the lightning to be intense as it generates nitric oxide and nitric oxide as is abundant on Venus as on Earth. We have surveyed almost all the Venus Express 128 Hz magnetometer data recorded to date. These data reveal that lightning is extensive on Venus but still do not reveal its true occurrence rate or altitude of generation. This requires observations from multipoint monitors at frequencies that penetrate into the ionosphere and will allow us to determine the energy released by lightning in the Venusian atmosphere. Finally, it is essential for us to study similar planetary processes in different settings in order to fully understand the process itself. Lightning is an important terrestrial process. Venus gives us the opportunity to understand the process more deeply. In this presentation we review the present state of knowledge of Venus lightning.

  11. Neutral Mass Spectrometry for Venus Atmosphere and Surface

    NASA Technical Reports Server (NTRS)

    Mahaffy, Paul

    2004-01-01

    The nature of the divergent evolution of the terrestrial planets Venus, Earth, and Mars is a fundamental problem in planetary science that is most relevant to understanding the characteristics of small planets we are likely to discover in extrasolar systems and the number of such systems that may support habitable environments. For this reason, the National Research Council's Decadal Survey gives Venus exploration high priority. That report was the basis of the NASA selection of Venus as one of four prime mission targets for the recently initiated New Frontiers Program. If the Decadal Survey priorities are to be realized, in situ Venus exploration must remain a high priority. Remote sensing orbital and in situ atmospheric measurements from entry probe or balloon platforms might be realized under the low cost Discovery missions while both atmospheric and landed surface measurements are envisioned with the intermediate class missions of the New Frontiers Program.

  12. The Atmosphere and Climate of Venus

    NASA Astrophysics Data System (ADS)

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

    Venus lies just sunward of the inner edge of the Sun's habitable zone. Liquid water is not stable. Like Earth and Mars, Venus probably accreted at least an ocean's worth of water, although there are alternative scenarios. The loss of this water led to the massive, dry CO2 atmosphere, extensive H2SO4 clouds (at least some of the time), and an intense CO2 greenhouse effect. This chapter describes the current understanding of Venus' atmosphere, established from the data of dozens of spacecraft and atmospheric probe missions since 1962, and by telescopic observations since the nineteenth century. Theoretical work to model the temperature, chemistry, and circulation of Venus' atmosphere is largely based on analogous models developed in the Earth sciences. We discuss the data and modeling used to understand the temperature structure of the atmosphere, as well as its composition, cloud structure, and general circulation. We address what is known and theorized about the origin and early evolution of Venus' atmosphere. It is widely understood that Venus' dense CO2 atmosphere is the ultimate result of the loss of an ocean to space, but the timing of major transitions in Venus' climate is very poorly constrained by the available data. At present, the bright clouds allow only 20% of the sunlight to drive the energy balance and therefore determine conditions at Venus' surface. Like Earth and Mars, differential heating between the equator and poles drives the atmospheric circulation. Condensable species in the atmosphere create clouds and hazes that drive feedbacks that alter radiative forcing. Also in common with Earth and Mars, the loss of light, volatile elements to space produces long-term changes in composition and chemistry. As on Earth, geologic processes are most likely modifying the atmosphere and clouds by injecting gases from volcanos as well as directly through chemical reactions with the surface. The sensitivity of Venus' atmospheric energy balance is quantified in

  13. Venus - Mead Crater

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This Magellan image mosaic shows the largest (275 kilometers in diameter [170 miles]) impact crater known to exist on Venus at this point in the Magellan mission. The crater is located north of Aphrodite Terra and east of Eistla Regio at latitude 12.5 degrees north and longitude 57.4 degrees east, and was imaged during Magellan orbit 804 on November 12, 1990. The Magellan science team has proposed to name this crater Mead, after Margaret Mead, the American Anthropologist (1901- 1978). All Magellan-based names of features on Venus are, of course, only proposed until final approval is given by the International Astronomical Union-Commission on Planetary Nomenclature. Mead is classified as a multi-ring crater with its innermost, concentric scarp being interpreted as the rim of the original crater cavity. No inner peak-ring of mountain massifs is observed on Mead. The presence of hummocky, radar-bright crater ejecta crossing the radar-dark floor terrace and adjacent outer rim scarp suggests that the floor terrace is probably a giant rotated block that is concentric to, but lies outside of, the original crater cavity. The flat, somewhat brighter inner floor of Mead is interpreted to result from considerable infilling of the original crater cavity by impact melt and/or by volcanic lavas. To the southeast of the crater rim, emplacement of hummocky ejecta appears to have been impeded by the topography of preexisting ridges, thus suggesting a very low ground-hugging mode of deposition for this material. Radar illumination on this and all other Magellan image products is from the left to the right in the scene.

  14. Venus Atmospheric Maneuverable Platform (VAMP) - A Low Cost Venus Exploration Concept

    NASA Astrophysics Data System (ADS)

    Lee, G.; Polidan, R. S.; Ross, F.

    2015-12-01

    The Northrop Grumman Aerospace Systems and L-Garde team has been developing an innovative mission concept: a long-lived, maneuverable platform to explore the Venus upper atmosphere. This capability is an implementation of our Lifting Entry Atmospheric Flight (LEAF) system concept, and the Venus implementation is called the Venus Atmospheric Maneuverable Platform (VAMP). The VAMP concept utilizes an ultra-low ballistic coefficient (< 50 Pa), semi-buoyant aircraft that deploys prior to entering the Venus atmosphere, enters without an aeroshell, and provides a long-lived (months to a year) maneuverable vehicle capable of carrying science instruments to explore the Venus upper atmosphere. In this presentation we provide an update on the air vehicle design and a low cost pathfinder mission concept that can be implemented in the near-term. The presentation also provides an overview of our plans for future trade studies, analyses, and prototyping to advance and refine the concept. We will discuss the air vehicle's entry concepts of operations (CONOPs) and atmospheric science operations. We will present a strawman concept of a VAMP pathfinder, including ballistic coefficient, planform area, percent buoyancy, wing span, vehicle mass, power supply, propulsion, materials considerations, structural elements, and instruments accommodation. In this context, we will discuss the following key factors impacting the design and performance of VAMP: Entry into the Venus atmosphere, including descent profile, heating rate, total heat load, stagnation, and acreage temperatures Impact of maximum altitude on air vehicle design and entry heating Candidate thermal protection system (TPS) requirements We will discuss the interdependencies of the above factors and the manner in which the VAMP pathfinder concept's characteristics affect the CONOPs and the science objectives. We will show how the these factors provide constraints as well as enable opportunities for novel long duration

  15. High Altitude Venus Operational Concept (HAVOC): Proofs of Concept

    NASA Technical Reports Server (NTRS)

    Jones, Christopher A.; Arney, Dale C.; Bassett, George Z.; Clark, James R.; Hennig, Anthony I.; Snyder, Jessica C.

    2015-01-01

    The atmosphere of Venus is an exciting destination for both further scientific study and future human exploration. 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 at 50 kilometers. Key technical challenges for the mission include performing the aerocapture maneuvers at Venus and Earth, inserting and inflating the airship at Venus during the entry sequence, and protecting the solar panels and structure from the sulfuric acid in the atmosphere. Two proofs of concept were identified that would aid in addressing some of the key technical challenges. To mitigate the threat posed by the sulfuric acid ambient in the atmosphere of Venus, a material was needed that could protect the systems while being lightweight and not inhibiting the performance of the solar panels. The first proof of concept identified candidate materials and evaluated them, finding FEP-Teflon (Fluorinated Ethylene Propylene-Teflon) to maintain 90 percent transmittance to relevant spectra even after 30 days of immersion in concentrated sulfuric acid. The second proof of concept developed and verified a packaging algorithm for the airship envelope to inform the entry, descent, and inflation analysis.

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

    NASA Astrophysics Data System (ADS)

    Rengel, Miriam; Hartogh, Paul; Jarchow, Christopher

    2008-08-01

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

  17. Dynamics investigation in the Venus upper atmosphere

    NASA Astrophysics Data System (ADS)

    Migliorini, A.; Altieri, F.; Shakun, A.; Zasova, L.; Piccioni, G.; Bellucci, G.

    The O_2 nightglow emissions in the infrared spectral range are important features to investigate dynamics at the mesospheric altitudes, in the planetary atmosphere. In this work, we analyzed the profiles obtained at limb by the VIRTIS spectrometer on board the Venus Express mission, acquired during the mission period from 2006-07-05 to 2008-08-15 to investigate possible gravity waves characteristics at the airglow altitudes. Indeed, several profiles present double peaked structures that can be interpreted as due to gravity waves. In analogy to the Earth's and Mars cases, we use a well-known theory to model the O_2 nightglow emissions affected by gravity waves propagation, in order to support this thesis and derive the waves properties. We discuss results from 30 profiles showing double peaked structures, focusing on vertical wavelength and wave amplitude of the possible gravity waves. On average, the double peaked profiles are compatible with the effects of gravity waves with a vertical wavelength ranging between 7 and 16 km, and wave amplitude of 3-14%. A comparison with gravity waves properties in the Mars and Earth's atmospheres, using the same theory, is also proposed \\citep{altieri_2014}. \\ The research is supported by ASI (contract ASI-INAF I/050/10/0).

  18. Venus Atmospheric Circulation from Digital Tracking of VMC Images

    NASA Astrophysics Data System (ADS)

    Limaye, S.; Moissl, R.; Markiewicz, W.; Titov, D.

    2008-09-01

    The Venus Monitoring Camera on Venus Express has been returning images of Venus in four filters since April 2006 on almost every orbit. These images portray the southern hemisphere of Venus at spatial resolutions ranging from ~ 50 km per pixel to better than ~ 10 km per pixel depending on when the planet was imaged from orbit. Images covering a substantial portion of the planet and separated by ~ 45 min to one hour have been mapped into rectilinear projection to enable use of digital tracking technique for the measurement of cloud motions on an orbit by orbit basis. The aggregate results are in good agreement with visual tracking results as well as from the previous missions [1] and show evidence of temporal variations, large scale waves and solar thermal tides in low and mid latitudes. The digital tracking results for the meridional component confirm the poleward flow increasing from low latitudes to mid-latitudes and then showing a tendency to weaken. However, the confidence in high latitude measurements is lower due to the peculiar nature of the cloud morphology that is generally streaky and quite different from the low latitudes. The meridional profile of the average zonal wind at higher latitudes is of considerable interest. At high and polar latitudes, a vortex organization is evident in the data consistently, with the core region centered over the pole. The images show variability in structure of the ultraviolet signature of the "S" shaped feature seen in the VIRTIS data on the capture orbit [2]. However, the cloud morphologies seen poleward of ~ 50 degrees latitude also makes digital tracking less reliable due to absence of discrete features at the spatial resolution of the VMC images acquired in the apoapsis portion of the Venus Express orbit. It is expected that images obtained closer to the planet will enable a determination of the zonal wind profile with better confidence which will be useful in elucidating the nature of the transient features seen in

  19. Signs of Life on Venus

    NASA Astrophysics Data System (ADS)

    Ksanfomality, L.

    2012-04-01

    The search for "habitable zones" in extrasolar planetary systems is based on the premise of "normal" physical conditions in a habitable zone, i.e. pressure, temperature range, and atmospheric composition similar to those on the Earth. However, one should not exclude completely the possibility of the existence of life at relatively high temperatures, despite the fact that at the first glance it seems impossible. The planet Venus with its dense, hot (735 K), oxigenless CO2 - atmosphere and high 92 bar-pressure at the surface could be the natural laboratory for the studies of this type. Amid exoplanets, celestial bodies with the physical conditions similar to the Venusian can be met. The only existing data of actual close-in observations of Venus' surface are the results of a series of missions of the soviet VENERA landers which took place the 1970's and 80's in the atmosphere and on the surface of Venus. For 36 and 29 years since these missions, respectively, I repeatedly returned to the obtained images of the Venus' surface in order to reveal on them any unusual objects observed in the real conditions of Venus. The new analysis of the Venus' panoramas was based on the search of unusual elements in two ways. Since the efficiency of the VENERA landers maintained for a long time they produced a large number of primary television panoramas during the lander's work. Thus, one can try to detect: (a) any differences in successive images (appearance or disappearance of parts of the image or change of their shape), and understand what these changes are related to (e.g., wind), and whether they are related to hypothetical habitability of a planet. Another sign (b) of the wanted object is their morphological peculiarities which distinguishes them from the ordinary surface details. The results of VENERA-9 (1975) and VENERA -13 (1982) are of the main interest. A few relatively large objects ranging from a decimeter to half meter and with unusual morphology were observed in some

  20. Evolution of Science Operations after 10 years of the Mars Express Mission

    NASA Astrophysics Data System (ADS)

    Cardesin Moinelo, Alejandro; Martin, Patrick

    2013-10-01

    The Mars Express mission was launched in June 2003 and has been providing great amounts of data since its arrival to Mars in Christmas 2003, covering a wide range of science objectives at all levels, from the surface and sub-surface geology, atmosphere dynamics and composition, up to the interaction with the magnetosphere and the characterization of the Martian sytem including its two moons, Phobos and Deimos. In these last 10 years, the Mars Express Science Operations Center has been responsible for the coordination of the scientific requirements and the implementation of the science plan, aiming to obtain the maximum scientific return of the mission while respecting the operational constraints. In this contribution we will show some of the operational challenges of the mission, focusing on the improvements and adaptations of the past years, not only in terms of technical and scientific requirements which have been varying with time, but also the optimization of the interfaces with all the teams involved.

  1. Evidence For And Against 8-day Planetary Waves In Ground-based Cloud-tracking Observations Of Venus' Nightside

    NASA Astrophysics Data System (ADS)

    Young, Eliot F.; Bullock, M. A.; Limaye, S.; Bailey, J.; Tsang, C. C. C.

    2010-10-01

    Several groups have estimated wind fields on Venus by tracking clouds that appear as silhouettes on Venus’ nightside in CO2 windows at 1.74 or 2.3 microns. In 2008, we presented 10 days of cloud-tracking results from July 2004 that suggested the presence of an 8-day wave manifested by velocity variations in clouds presumed to be at altitudes of 48 - 55 km. A variety of waves are key predictions of recent Venus GCMs (e.g., Yamamoto and Takahashi 2006, Lebonnois et al. 2010) and important areas of comparison between observations and modeling efforts. Although we have measured equatorial zonal wind velocity variations of 15 m/s for observations separated by 24 hours, Hueso, Peralta and Sanchez-Lavega (2010) presented cloud-tracking results from VIRTIS-M image sequences in which velocities are mostly confined to 55 to 65 m/s in the 30°S - 10°S latitude range. We now present cloud-tracking results from ground-based observations obtained during July and September 2007. On some dates we are able to combine observations between the AAT and IRTF to increase the time baseline between images to roughly 4 hours and reduce the errors by about a factor of two. Akatsuki image sequences should resolve the question of zonal velocity variations in the near future. --- References Hueso, Peralta and Sanchez-Lavega, 2010, "Temporal and spatial variability of Venus winds at cloud level from VIRTIS during the Venus Express mission.” Presented at the Venus Express Workshop in Aussois, June 2010. Lebonnois et al., 2010, "Superrotation of Venus’ atmosphere analyzed with a full general circulation model.” JGR 115, E06006. Yamamoto and Takahashi, 2006, "Superrotation maintained by meridional circulation and waves in a Venus-like AGCM.” J. Amtos Sci., 63, 3296.

  2. Artist concept of Magellan spacecraft orbiting Venus

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Magellan spacecraft orbits Venus in this artist concept. The continued quest for detailed topographic measurements of Venus will again be undertaken in April 1989 by Magellan, named after the 16th century Portuguese explorer. Magellan will orbit Venus about once every three hours, acquiring radar data for 37 minutes of each orbit when it is closest to the surface. Using an advanced instrument called a synthetic aperature radar (SAR), it will map more than 90 per cent of the surface with resolution ten times better than the best prior spacecraft. Magellan is managed by the Jet Propulsion Laboratory (JPL); Martin Marietta is developing the spacecraft and Hughes Aircraft Company, the advanced imaging radar. Magellan will be deployed from the payload bay (PLB) of Atlantis, Orbiter Vehicle (OV) 104, during mission STS-30.

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

    NASA Technical Reports Server (NTRS)

    Dorfman, S. D.

    1973-01-01

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

  4. Colonization of Venus

    NASA Astrophysics Data System (ADS)

    Landis, Geoffrey A.

    2003-01-01

    Although the surface of Venus is an extremely hostile environment, at about 50 kilometers above the surface the atmosphere of Venus is the most earthlike environment (other than Earth itself) in the solar system. It is proposed here that in the near term, human exploration of Venus could take place from aerostat vehicles in the atmosphere, and that in the long term, permanent settlements could be made in the form of cities designed to float at about fifty kilometer altitude in the atmosphere of Venus.

  5. Venus in Violet and Near Infrared Light

    NASA Technical Reports Server (NTRS)

    1990-01-01

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

  6. Venusian upper haze properties from UV to IR wavelengths: results from SPICAV/SOIR on Venus Express

    NASA Astrophysics Data System (ADS)

    Montmessin, Franck; Fedorova, Anna; Wilquet, Valerie; Mahieux, Arnaud; Korablev, Oleg; Bertaux, Jean-Loup; Vandaele, Ann-Carine

    The SPICAV suite of instruments is composed of three separate channels: UV (110 to 320 nm), near-IR (0.7 to 1.7 µm) and the SOIR channel (2.3 to 4.4 µm). On specific opportunities, all three channels have operated simultaneously during solar occultations and have provided almost contiguous spectral information from 0.11 to 4.4 µm. Occultation observations provide several advantages, in particular it does not require cross-calibrating the channels together as scientific analysis is based on relative measurements; i.e. atmospheric transmissions which are the ratio of spectra obtained at a given altitude where the atmosphere produces some attenuation onto that collected outside the atmosphere where the sun can be observed free of any absorption. Haze opacities are readily retrieved using Beer-Lambert's law and vertical distribution from 65 to 120 km is inferred using regular onion peeling technique. Over the interval covered by SPICAV/SOIR, the spectral behavior of haze particles can be fully and robustly evaluated since the size parameter varies by more than one order of magnitude. Extraction of extinction coefficients have been performed for all three channels, allowing derivation of size distribution parameters. Details on the observations made for each channel will be presented. Profiles exhibit peculiar wavy structures that suggest gravity wave vertical propagations or localized destruction processes. Size distribution results will be discussed, in particular the possibility for a multi-modal distribution potentially implying different processes of formation and destruction at work in the mesosphere of Venus.

  7. Venus round trip using solar sail

    NASA Astrophysics Data System (ADS)

    Zhu, KaiJian; Zhang, RongZhi; Xu, Dong; Wang, JiaSong; Li, ShaoMin

    2012-08-01

    Trajectory optimization and simulation is performed for Venus round trip (VeRT) mission using solar sail propulsion. Solar gravity is included but atmospheric drag and shadowing effects are neglected in the planet-centered escape and capture stages. The spacecraft starts from the Geostationary orbit (GEO) at a predetermined time to prepare a good initial condition for the Earth-Venus transfer, although the launch window is not an issue for spacecraft with solar sails. The Earth-Venus phase and the return trip are divided into three segments. Two methods are adopted to maintain the mission trajectory for the VeRT mission and then compared through a numerical simulation. According to the first approach, Planet-centered and heliocentric maneuvers are modeled using a set of blended analytical control laws instead of the optimal control techniques. The second procedure is the Direct Attitude Angle Optimization in which the attitude angles of the solar sail are adopted as the optimization variables during the heliocentric transfer. Although neither of the two methods guarantees a globally optimal trajectory, they are more efficient and will produce a near-optimal solution if employed properly. The second method has produced a better result for the minimum-time transfer of the VeRT mission demonstrating the effectiveness of the methods in the preliminary design of the complex optimal interplanetary orbit transfers.

  8. Registration of VENUS peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    VENUS is a large-seeded high-oleic Virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) that has enhanced Sclerotinia blight and pod rot resistance when compared to the cultivar Jupiter. VENUS is the first high-oleic Virginia peanut developed for optimal performance in the South...

  9. Modelling of ultraviolet and visible dayglow emissions on Venus

    NASA Astrophysics Data System (ADS)

    Jain, Sonal Kumar; Bhardwaj, Anil

    The ultraviolet dayglow emissions on Venus is mainly dominated by the CO _{2} and its dissociated products (CO, O, and C). The SPICAV instrument on-board Venus Express (VEx) has recently made first observation of CO Cameron and CO _{2}(+) UV doublet emissions in the dayglow of Venus. We have developed a model to study the ultraviolet and visible dayglow emissions on Venus for low, moderate, and high solar activity conditions. Our calculation shows that CO Cameron band emission on Venus is mainly produced by electron impact excitation of CO (e-CO), however, this process is sensitive to the e-CO cross section used in the calculation. At the altitude of emission peak (˜135 km), the model predicted limb intensity of CO Cameron band and CO _{2}(+) UV doublet emissions in moderate (F10.7 = 130) solar activity condition is about 2400 and 300 kR, respectively, which is in agreement with the very recently published SPICAV/Venus Express observation A model for N _{2} triplet band emissions is developed to predict the intensity of these emissions on Venus. We have developed a detail coupled chemistry model to understand the various processes governing the oxygen ultraviolet (2972 Å), and visible (green and red lines) emission on Venus. The results will be presented and discussed.

  10. 2-D Chemical-Dynamical Modeling of Venus's Sulfur Variability

    NASA Astrophysics Data System (ADS)

    Bierson, Carver J.; Zhang, Xi

    2016-10-01

    Over the last decade a combination of ground based and Venus Express observations have been made of the concentration of sulfur species in Venus's atmosphere, both above [1, 2] and below the clouds [3, 4]. These observations put constraints on both the vertical and meridional variations of the major sulfur species in Venus's atmosphere.. It has also been observed that SO2 concentrations varies on both timescales of hours and years [1,4]. The spatial and temporal distribution of tracer species is owing to two possibilities: mutual chemical interaction and dynamical tracer transport.Previous Chemical modeling of Venus's middle atmosphere has only been explored in 1-D. We will present the first 2-D (altitude and latitude) chemical-dynamical model for Venus's middle atmosphere. The sulfur chemistry is based on of the 1D model of Zhang et al. 2012 [5]. We do model runs over multiple Venus decades testing two scenarios: first one with varying sulfur fluxes from below, and second with secular dynamical perturbations in the atmosphere [6]. By comparing to Venus Express and ground based observations, we put constraints on the dynamics of Venus's middle atmosphere.References: [1] Belyaev et al. Icarus 2012 [2] Marcq et al. Nature geoscience, 2013 [3] Marcq et al. JGR:Planets, 2008 [4] Arney et al. JGR:Planets, 2014 [5] Zhang et al. Icarus 2012 [6] Parish et al. Icarus 2012

  11. Properties of planetward ion flows in Venus' magnetotail

    NASA Astrophysics Data System (ADS)

    Kollmann, P.; Brandt, P. C.; Collinson, G.; Rong, Z. J.; Futaana, Y.; Zhang, T. L.

    2016-08-01

    Venus is gradually losing some of its atmosphere in the form of ions through its induced magnetotail. Some of these ions have been reported previously to flow back to the planet. Proposed drivers are magnetic reconnection and deflection of pickup ions in the magnetic field. We analyze protons and oxygen ions with eV to keV energies acquired by the ASPERA-4/IMA instrument throughout the entire Venus Express mission. We find that venusward flowing ions are important in the sense that their density and deposition rate into the atmosphere is of the same order of magnitude as the density and escape rate of downtail flowing ions. Our analysis shows that during strong EUV irradiance, which occurs during solar maximum, the flux of venusward flowing protons is weaker and of oxygen ions is stronger than during weak irradiance. Since such a behavior was observed when tracing oxygen ions through a MHD model, the ultimate driver of the venusward flowing ions may simply be the magnetic field configuration around Venus. Although the pure downtail oxygen flux stays mostly unchanged for all observed EUV conditions, the increase in venusward oxygen flux for high irradiance results in a lower net atmospheric escape rate. Venusward bulk flows are mostly found in locations where the magnetic field is weak relative to the interplanetary conditions. Although a weak field is generally an indicator of proximity to the magnetotail current sheet, these flows do not cluster around current sheet crossings, as one may expect if they would be driven by magnetic reconnection.

  12. Ion flows in Venus' magnetotail

    NASA Astrophysics Data System (ADS)

    Kollmann, P.; Brandt, P. C.; Futaana, Y.; Fedorov, A.

    2014-12-01

    The plasma environment of Venus, including its magnetotail up to 3 Venus radii distance has been studied by the Venus Express spacecraft since 2006. We use the ASPERA/IMA instrument that measures protons and oxygen ions in the eV to keV range. Oxygen ions deriving from Venus' atmosphere and flowing down the magnetotail have been reported and contribute to atmospheric escape (Barabash et al. 2007). There have also been ions observed that flow Venusward in the tail (Dubinin et al. 2014). Signatures of magnetic reconnection have been found (Zhang et al. 2012), which might contribute to these flows. We have numerically calculated flow velocities and densities of protons and oxygen ions in the tail. Since the IMA instrument cannot cover all directions during one scan, we manually identified hundreds of cases of clear and mostly unbiased plasma flows. This approach avoids cases that lead to incorrect results. We find that the Venusward fluxes of both protons and oxygen ions are on average smaller but on the same order of magnitude as the tailward escape fluxes. Venusward fluxes are commonly quasi-steady i.e. observed throughout most of a tail passage, which takes several ten minutes. The instantaneous flow directions can differ by more than 100 degrees in the tail. Their net tailward or Venusward direction is opposite in about half of the cases. Comparison with magnetic field data shows that tailward and Venusward bulk flows are roughly field-aligned. The calculation of plasma moments does not imply that the underlying distributions are thermal and described well with a Maxwellian distribution. About a third of the proton spectra show a suprathermal component. Such cases are more common for Venusward fluxes and can be observed over longer periods. In some cases the additional component is a clearly separated second peak but most of the time it fits well with a flat power law (exponents 0 to 3).

  13. Tidal constraints on the interior of Venus

    NASA Astrophysics Data System (ADS)

    Dumoulin, Caroline; Tobie, Gabriel; Verhoeven, Olivier; Rosenblatt, Pascal; Rambaux, Nicolas

    2016-10-01

    As a prospective study for a future exploration of Venus, we propose to systematically investigate the signature of the internal structure in the gravity field and the rotation state of Venus, through the determination of the moment of inertia and the tidal Love number.We test various mantle compositions, core size and density as well as temperature profiles representative of different scenarios for formation and evolution of Venus. The mantle density ρ and seismic vP and vS wavespeeds are computed in a consistent manner from given temperature and composition using the Perple X program. This method computes phase equilibria and uses the thermodynamics of mantle minerals developped by Stixrude and Lithgow-Bertelloni (2011).The viscoelastic deformation of the planet interior under the action of periodic tidal forces are computed following the method of Tobie et al. (2005).For a variety of interior models of Venus, the Love number, k2, and the moment of inertia factor are computed following the method described above. The objective is to determine the sensitivity of these synthetic results to the internal structure. These synthetic data are then used to infer the measurement accuracies required on the time-varying gravitational field and the rotation state (precession rate, nutation and length of day variations) to provide useful constraints on the internal structure.We show that a better determination of k2, together with an estimation of the moment of inertia, the radial displacement, and of the time lag, if possible, will refine our knowledge on the present-day interior of Venus (size of the core, mantle temperature, composition and viscosity). Inferring these quantities from a future ex- ploration mission will provide essential constraints on the formation and evolution scenarios of Venus.

  14. Explosive propulsion applications. [to future unmanned missions

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  15. COMPASS Final Report: Advanced Lithium Ion Venus Explorer (ALIVE)

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; Paul, Michael

    2016-01-01

    The COncurrent Multi-disciplinary Preliminary Assessment of Space Systems (COMPASS) Team partnered with the Applied Research Laboratory to perform a NASA Innovative Advanced Concepts (NIAC) Program study to evaluate chemical based power systems for keeping a Venus lander alive(power and cooling) and functional for a period of days. The mission class targeted was either a Discovery ($500M) or New Frontiers ($750M to $780M) class mission. Historic Soviet Venus landers have only lasted on the order of 2 hours in the extreme Venus environment: temperatures of 460 C and pressures of 93 bar. Longer duration missions have been studied using plutonium powered systems to operate and cool landers for up to a year. However, the plutonium load is very large. This NIAC study sought to still provide power and cooling but without the plutonium.

  16. Salt tectonics on Venus

    SciTech Connect

    Wood, C.A.; Amsbury, D.

    1986-05-01

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

  17. Pioneer Venus Data Analysis

    NASA Technical Reports Server (NTRS)

    Jones, Douglas E.

    1996-01-01

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

  18. Venus Gravity Handbook

    NASA Technical Reports Server (NTRS)

    Konopliv, Alexander S.; Sjogren, William L.

    1996-01-01

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

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

    SciTech Connect

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

    2011-04-15

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

  20. AKATSUKI returns to Venus

    NASA Astrophysics Data System (ADS)

    Nakamura, Masato; Imamura, Takeshi; Ishii, Nobuaki; Abe, Takumi; Kawakatsu, Yasuhiro; Hirose, Chikako; Satoh, Takehiko; Suzuki, Makoto; Ueno, Munetaka; Yamazaki, Atsushi; Iwagami, Naomoto; Watanabe, Shigeto; Taguchi, Makoto; Fukuhara, Tetsuya; Takahashi, Yukihiro; Yamada, Manabu; Imai, Masataka; Ohtsuki, Shoko; Uemizu, Kazunori; Hashimoto, George L.; Takagi, Masahiro; Matsuda, Yoshihisa; Ogohara, Kazunori; Sato, Naoki; Kasaba, Yasumasa; Kouyama, Toru; Hirata, Naru; Nakamura, Ryosuke; Yamamoto, Yukio; Horinouchi, Takeshi; Yamamoto, Masaru; Hayashi, Yoshi-Yuki; Kashimura, Hiroki; Sugiyama, Ko-ichiro; Sakanoi, Takeshi; Ando, Hiroki; Murakami, Shin-ya; Sato, Takao M.; Takagi, Seiko; Nakajima, Kensuke; Peralta, Javier; Lee, Yeon Joo; Nakatsuka, Junichi; Ichikawa, Tsutomu; Inoue, Kozaburo; Toda, Tomoaki; Toyota, Hiroyuki; Tachikawa, Sumitaka; Narita, Shinichiro; Hayashiyama, Tomoko; Hasegawa, Akiko; Kamata, Yukio

    2016-05-01

    AKATSUKI is the Japanese Venus Climate Orbiter that was designed to investigate the climate system of Venus. The orbiter was launched on May 21, 2010, and it reached Venus on December 7, 2010. Thrust was applied by the orbital maneuver engine in an attempt to put AKATSUKI into a westward equatorial orbit around Venus with a 30-h orbital period. However, this operation failed because of a malfunction in the propulsion system. After this failure, the spacecraft orbited the Sun for 5 years. On December 7, 2015, AKATSUKI once again approached Venus and the Venus orbit insertion was successful, whereby a westward equatorial orbit with apoapsis of ~440,000 km and orbital period of 14 days was initiated. Now that AKATSUKI's long journey to Venus has ended, it will provide scientific data on the Venusian climate system for two or more years. For the purpose of both decreasing the apoapsis altitude and avoiding a long eclipse during the orbit, a trim maneuver was performed at the first periapsis. The apoapsis altitude is now ~360,000 km with a periapsis altitude of 1000-8000 km, and the period is 10 days and 12 h. In this paper, we describe the details of the Venus orbit insertion-revenge 1 (VOI-R1) and the new orbit, the expected scientific information to be obtained at this orbit, and the Venus images captured by the onboard 1-µm infrared camera, ultraviolet imager, and long-wave infrared camera 2 h after the successful initiation of the VOI-R1.

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

    NASA Technical Reports Server (NTRS)

    Acheson, L. K.

    1973-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  3. Pioneer Venus Orbiter Ultraviolet Spectrometer: Operations and Data Analysis

    NASA Technical Reports Server (NTRS)

    Stewart, A. I. F.

    1997-01-01

    The Ultraviolet Spectrometer investigation on the Pioneer Venus Orbiter mission was extremely successful. The instrument was designed, built and tested at CU/LASP and delivered on time and within budget. The spacecraft and its instruments were required to operate for 243 days in Venus orbit. OUVS operated successfully for a further 13 years with only minor problems. The major scientific results listed above that deal with Venus were all unexpected and significant discoveries. The Comet Halley observations came about because of a favorable alignment of Halley, the Sun, and Venus, and were an important contribution to the international study of this comet. The scientific results of the OUVS investigation are to be found in the 41 papers listed in section 4 below. OUVS data provided material for 6 PhD and one MS dissertations, listed in section 5 below.

  4. Artist concept of Magellan spacecraft in elliptical orbit around Venus

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Magellan spacecraft is shown in elliptical orbit around Venus, collecting data (radar mapping), and then transmitting data back to Earth in this artist concept. When the spacecraft orbit is close to Venus the synthetic aperature radar (SAR) will image a swath between 9 and 15 nautical miles (10 and 17 statute miles), beginning at or near the north pole and continuing to the southern hemisphere. Subsequent swaths will slightly overlap and, during its primary mission, the spacecraft will map most of the planet. When the spacecraft moves into the part of its elliptical orbit farthest from Venus, the spacecraft high-gain antenna will be turned toward Earth and will send the data collected during the imaging to Earth. Magellan, named after the 16th century Portuguese explorer, will orbit Venus about once every three hours, acquiring radar data for 37 minutes of each orbit. Magellan is managed by the Jet Propulsion Laboratory (JPL); Martin Marietta is developing the spacecraft and Hughes Air

  5. Artist concept of Magellan spacecraft in elliptical orbit around Venus

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Magellan spacecraft is shown in elliptical orbit around Venus, collecting data (radar mapping), and then transmitting data back to Earth in this artist concept. When the spacecraft orbit is close to Venus the synthetic aperature radar (SAR) will image a swath between 9 and 15 nautical miles (10 and 17 statute miles) (highlighted in image), beginning at or near the north pole and continuing to the southern hemisphere. Subsequent swaths will slightly overlap and, during its primary mission, the spacecraft will map most of the planet. When the spacecraft moves into the part of its elliptical orbit farthest from Venus, the spacecraft high-gain antenna will be turned toward Earth and will send the data collected during the imaging to Earth. Magellan, named after the 16th century Portuguese explorer, will orbit Venus about once every three hours, acquiring radar data for 37 minutes of each orbit. Magellan is managed by the Jet Propulsion Laboratory (JPL); Martin Marietta is developing the sp

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

    USGS Publications Warehouse

    Ivanov, Mikhail A.; Head, James W.

    2008-01-01

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

  7. The thermal balance of the lower atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Tomasko, M. G.

    1981-01-01

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

  8. Solar Flight on Mars and Venus

    NASA Astrophysics Data System (ADS)

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

    2002-10-01

    . Fleets of solar-powered aircraft could provide an architecture for efficient and low-cost comprehensive coverage for a variety of scientific missions. Exploratory planetary mapping and atmospheric sampling can lead to a greater understanding of the greenhouse effect not only on Venus but on Earth as well.

  9. Solar Flight on Mars and Venus

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    . Fleets of solar-powered aircraft could provide an architecture for efficient and low-cost comprehensive coverage for a variety of scientific missions. Exploratory planetary mapping and atmospheric sampling can lead to a greater understanding of the greenhouse effect not only on Venus but on Earth as well.

  10. Transits of Venus and Mercury as muses

    NASA Astrophysics Data System (ADS)

    Tobin, William

    2013-11-01

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

  11. Astrobiology and Venus exploration

    NASA Astrophysics Data System (ADS)

    Grinspoon, David H.; Bullock, Mark A.

    For hundreds of years prior to the space age, Venus was considered among the most likely homes for extraterrestrial life. Since planetary exploration began, Venus has not been considered a promising target for Astrobiological exploration. However, Venus should be central to such an exploration program for several reasons. At present Venus is the only other Earth-sized terrestrial planet that we know of, and certainly the only one we will have the opportunity to explore in the foreseeable future. Understanding the divergence of Earth and Venus is central to understanding the limits of habitability in the inner regions of habitable zones around solar-type stars. Thus Venus presents us with a unique opportunity for putting the bulk properties, evolution and ongoing geochemical processes of Earth in a wider context. Many geological and meteorological processes otherwise active only on Earth at present are currently active on Venus. Active volcanism most likely affects the climate and chemical equilibrium state of the atmosphere and surface, and maintains the global cloud cover. Further, if we think beyond the specifics of a particular chemical system required to build complexity and heredity, we can ask what general properties a planet must possess in order to be considered a possible candidate for life. The answers might include an atmosphere with signs of flagrant chemical disequilibrium and active, internally driven cycling of volatile elements between the surface, atmosphere and interior. At present, the two planets we know of which possess these characteristics are Earth and Venus. Venus almost surely once had warm, habitable oceans. The evaporation of these oceans, and subsequent escape of hydrogen, most likely resulted in an oxygenated atmosphere. The duration of this phase is poorly understood, but during this time the terrestrial planets were not isolated. Rather, due to frequent impact transport, they represented a continuous environment for early microbial

  12. SOHO Sees Venus' Approach

    NASA Video Gallery

    This video taken by the Solar and Heliospheric Observatory (SOHO) shows the Sun's corona and Venus' approach for the transit. This was taken with the Extreme ultraviolet Imaging Telescope (EIT) in ...

  13. The Atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Hansen, J. E. (Editor)

    1975-01-01

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

  14. 10. The surface and interior of venus

    USGS Publications Warehouse

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

    1977-01-01

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

  15. Solar Airplane Concept Developed for Venus Exploration

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2004-01-01

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

  16. Magellan - Communicating with a spacecraft at Venus

    NASA Technical Reports Server (NTRS)

    Burow, Nathan A.

    1987-01-01

    NASA's Magellan mission scheduled for launch in April 1989, using the Space Shuttle/Innertial Upper Stage configuration, will put a single spacecraft in orbit around Venus in order to map the planet's surface with SAR. The SAR's resolution will be enough to furnish surface details, and such geological features as tectonics, volcanic activity, surface faulting, and water and wind erosion. Attention is presently given to the telecommunications system that will be needed to transmit the 3.4 trillion bits of data which the SAR will acquire during the course of this mission.

  17. Plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1981-01-01

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

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

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

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

  19. Long-Lived, Maneuverable, Semi-Buoyant Platform for Venus Upper Atmosphere Exploration

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    This presentation discusses the continued development of the Northrop Grumman/L’GARDE team’s long-lived, maneuverable platform to explore the Venus upper atmosphere. It focuses on the overall mission architecture and concept of operations.

  20. Long-term Behaviour Of Venus Winds At Cloud Level From Virtis/vex Observations

    NASA Astrophysics Data System (ADS)

    Hueso, Ricardo; Peralta, J.; Sánchez-Lavega, A.; Pérez-Hoyos, S.; Piccioni, G.; Drossart, P.

    2009-09-01

    The Venus Express (VEX) mission has been in orbit to Venus for more than three 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 an analysis of the overall dynamics of Venus’ atmosphere at both levels using observations that cover a large fraction of the VIRTIS dataset. We will present our latest results concerning the zonal winds, the overall stability in the lower cloud deck motions and the variability in the upper cloud. Meridional winds are also observed in the upper and lower cloud in the UV and IR images obtained with VIRTIS. While the upper clouds present a net meridional motion consistent with the upper branch of a Hadley cell the lower cloud present more irregular, variable and less intense motions in the meridional direction. Acknowledgements This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07. RH acknowledges a "Ramón y Cajal” contract from MEC.

  1. Pioneer Venus data analysis for the retarding potential analyzer

    NASA Technical Reports Server (NTRS)

    Knudsen, William C.

    1993-01-01

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

  2. Vénus version Express

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    2010-04-01

    En avril 2006, Vénus a "capturé" un objet d'un genre particulier: une sonde robotique européenne, baptisée Venus Express et destinée à scruter cette planète sous tous les angles. Bilan de cette mission 5 ans après le lancement de la sonde, dont 4 d'observations vénusiennes.

  3. Near-field VLBI and its applications to Space Science Missions.

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    Near-field Very Long Baseline Interferometry (VLBI) is a radio astronomical technique that, when applied to observations of spacecraft, provides unique insights on those areas of space mission scientific return, which require precise determination of lateral position of spacecraft on the celestial sphere. The Planetary Radio Interferometry and Doppler Experiment (PRIDE) exploits near-field VLBI for accurate estimation of the state-vector of a spacecraft using arrays of radio telescopes available around the world. We will present new results of recent experiments with current ESA's missions (Venus Express, Mars Express, Gaia) while showing the numerous implementations of the PRIDE technique.

  4. Stopped-Rotor Cyclocopter for Venus Exploration

    NASA Technical Reports Server (NTRS)

    Husseyin, Sema; Warmbrodt, William G.

    2016-01-01

    The cyclocopter system can use two or more rotating blades to create lift, propulsion and control. This system is explored for its use in a mission to Venus. Cyclocopters are not limited to speed and altitude and can provide 360 degrees of vector thrusting which is favorable for good maneuverability. The novel aspect of this study is that no other cyclocopter configuration has been previously proposed for Venus or any (terrestrial or otherwise) exploration application where the cyclocopters rotating blades are stopped, and act as fixed wings. The design considerations for this unique planetary aerial vehicle are discussed in terms of implementing the use of a cyclorotor blade system combined with a fixed wing and stopped rotor mechanism. This proposed concept avoids many of the disadvantages of conventional-rotor stopped-rotor concepts and accounts for the high temperature, pressure and atmospheric density present on Venus while carrying out the mission objectives. The fundamental goal is to find an ideal design that implements the combined use of cyclorotors and fixed wing surfaces. These design concepts will be analyzed with the computational fluid dynamics tool RotCFD for aerodynamic assessment. Aspects of the vehicle design is 3D printed and tested in a small water tunnel or wind tunnel.

  5. VENUS Atmospheric Exploration by Solar Aircraft

    NASA Astrophysics Data System (ADS)

    Landis, G. A.; Lamarre, C.; Colozza, A.

    2002-01-01

    then climb back to higher altitudes and fly upwind to the original point, allowing both high and low altitudes to be probed. Analysis of flight using battery storage shows that it is not feasible to keep the aircraft aloft on battery power alone during the passage across the night side of the planet. Likewise, the unpowered glide range of the aircraft is not high enough for it to glide around the night side of the planet and re-emerge into sunlight. Therefore, if the mission duration is to be unlimited, the mission is restricted to the daylight side of the planet, and to altitudes high enough that the aircraft can equal or exceed the wind speed. would be a powerful tool for exploration. By learning how Venus can be so similar to Earth, and yet so different, we will learn to better understand the climate and geological history of the Earth. The success of a prototype solar airplane could lead to the development of a fleet of solar-powered airplanes flying across the Venus cloud tops, taking simultaneous measurements to develop a "snapshot" of the climate across the face of the planet. Fleets of solar-powered aircraft could provide an architecture for efficient and low-cost comprehensive coverage for a variety of scientific missions, both atmospheric and geological science via surface imaging and radar. Exploratory planetary mapping and atmospheric sampling can lead to a greater understanding of the greenhouse effect not only on Venus but on Earth as well.

  6. Status of development of lightning detector for PLANET-C mission

    NASA Astrophysics Data System (ADS)

    Takahashi, Y.; Hoshino, N.; Sato, M.; Teraguchi, T.

    2008-12-01

    Magnetometer onboard Venus Express detected whistler mode waves whose source can be considered to be lightning discharge occurring well below the spacecraft orbit. However, there still remain some uncertainties to conclude finally such waves are originated by lightning discharge in the atmosphere. In order to identify the discharge phenomena in the atmosphere of Venus without any doubt, we plan to observe the lightning activity with high-speed optical detector onboard Planet-C, the Japanese Venus Climate Orbiter mission which will be launched in 2010 by JAXA. We are developing a new type of lightning detector, LAC (Lightning and Airglow Camera). Main difference from other equipments which have provided evidences of lightning existence in Venus is the high-speed sampling rate at 50kHz for each pixel, enabling us to distinguish the optical lightning flash from other pulsing noises. On the other hand, spatial resolution is not first priority as the first detector of Venus lightning. New type of APD (avalanche photo diode) array with a format of 8 x 8 is used and a narrow band interference filter at wavelength of 777.4 nm (OI) is selected for lightning measurement. The development is now at the stage for designing and manufacturing the flight model, based on the performance and environmental tolerance of the proto model. Especially, the algorithm for self- triggering is carefully improved in order to exclude false-trigger by other pulse-like noise.

  7. Pioneer Venus polarimetry and haze optical thickness

    NASA Technical Reports Server (NTRS)

    Knibbe, W. J. J.; Wauben, W. M. F.; Travis, L. D.; Hovenier, J. W.

    1992-01-01

    The Pioneer Venus mission provided us with high-resolution measurements at four wavelengths of the linear polarization of sunlight reflected by the Venus atmosphere. These measurements span the complete phase angle range and cover a period of more than a decade. A first analysis of these data by Kawabata et al. confirmed earlier suggestions of a haze layer above and partially mixed with the cloud layer. They found that the haze exhibits large spatial and temporal variations. The haze optical thickness at a wavelength of 365 nm was about 0.06 at low latitudes, but approximately 0.8 at latitudes from 55 deg poleward. Differences between morning and evening terminator have also been reported by the same authors. Using an existing cloud/haze model of Venus, we study the relationship between the haze optical thickness and the degree of linear polarization. Variations over the visible disk and phase angle dependence are investigated. For that purpose, exact multiple scattering computations are compared with Pioneer Venus measurements. To get an impression of the variations over the visible disk, we have first studied scans of the polarization parallel to the intensity equator. After investigating a small subset of the available data we have the following results. Adopting the haze particle characteristics given by Kawabata et al., we find a thickening of the haze at increasing latitudes. Further, we see a difference in haze optical thickness between the northern and southern hemispheres that is of the same order of magnitude as the longitudinal variation of haze thickness along a scan line. These effects are most pronounced at a wavelength of 935 nm. We must emphasize the tentative nature of the results, because there is still an enormous amount of data to be analyzed. We intend to combine further polarimetric research of Venus with constraints on the haze parameters imposed by physical and chemical processes in the atmosphere.

  8. Venus - False Color of Bereghinya Planitia

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This false color Magellan image shows a portion of Bereghinya Planitia (plains) in the northern hemisphere of Venus, centered at 31 degrees north latitude, 43 degrees east longitude. The area is 260 kilometers (160 miles) wide and 330 kilometers (200 miles) long. This image was produced from Magellan radar data collected in Cycle 2 of the mission. Cycle 2 was completed January 15, 1992. The area was not imaged during the first cycle because of superior conjunction when the sun was between the Earth and Venus, preventing communication with the spacecraft. This image contains examples of several of the major geologic terrains on Venus and illustrates the basic stratigraphy or sequence of geologic events. The oldest terrains appear as bright, highly-fractured or chaotic highlands rising out of the plains. This is seen in the upper right and lower left quadrants of the image. The chaotic highlands, sometimes called tessera, may represent older and thicker crustal material and occupy about 15 percent of the surface of Venus. Plains surround and embay the fractured highland tessera. Plains are formed by fluid volcanic flows that may have once formed vast lava seas which covered all the low lying surfaces. Plains comprise more than 80 percent of the surface of Venus. The most recent activity in the region is volcanism that produced the radar bright flows best seen in the lower right quadrant of the image. The lava flows in this image are associated with the shield volcano Tepev Mons whose summit is near the lower left corner of the image. The flows are similar to the darker plains volcanics, but apparently have more rugged surfaces that more efficiently scatter the radar signal back to the spacecraft. The geologic sequence is early fracturing of the tessera, flooding by extensive plains lavas and scattered, less extensive individual flows on the plains surface. The simulated hues are based on color images recorded by the Soviet Venera 13 and 14 spacecraft.

  9. Energy Estimates of Lightning-Generated Whistler-Mode Waves in the Venus Ionosphere

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    The dual fluxgate magnetometer on the Venus Express Mission sampled at 128 Hz allowing for signals up to 64 Hz to be detected. These signals are found at all local times and at altitudes up to 600 km while near periapsis. The spacecraft had a periapsis within 15 degrees of the north pole for nearly the entire mission, concentrating observations at high latitudes. At solar minimum, when the ionosphere can become strongly magnetized, the waves were more readily guided along the field up to the spacecraft. During this time, whistlers were observed 3% of the time while VEX was at 250 km altitude. Detection rates reached 5% at this altitude while near the dawn terminator due to a low altitude magnetic belt that provides a radial component enabling better access of the signals to the spacecraft.Since the majority of these observations were made at relatively low altitudes, reasonable assumptions can be made about the ionospheric conditions along the wave's path from the base of the ionosphere to the spacecraft. The electron density can be inferred by utilizing the VERA model and scaling it to match the solar cycle conditions during the Venus Express campaign. With the electron density and the three components of the magnetic field measurement, we then calculate the Poynting flux to determine the energy density of the wave. This enables us to determine the strength of the source lightning and compares this strength to that on Earth.

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  11. Quantifying shapes of volcanoes on Venus

    NASA Technical Reports Server (NTRS)

    Garvin, J. B.

    1994-01-01

    A large population of discrete volcanic edifices on Venus has been identified and cataloged by means of Magellan SAR images, and an extensive database describing thousands of such features is in final preparation. Those volcanoes categorized as Intermediate to Large in scale, while relatively small in number (approx. 400), nonetheless constitute a significant volumetric component (approx. 13 x 10(exp 6) cu km) of the total apparent crustal volume of Venus. For this reason, we have focused attention on the morphometry of a representative suite of the larger edifices on Venus and, in particular, on ways of constraining the eruptive histories of these possibly geologically youthful landforms. Our approach has been to determine a series of reproducible morphometric parameters for as many of the discrete volcanoes on Venus that have an obvious expression within the global altimetry data acquired by Magellan. In addition, we have attempted to objectively and systematically define the mathematical essence of the shapes of these larger volcanoes using a polynomial cross-section approximation involving only parameters easily measured from digital topography, as well as with simple surface cylindrical harmonic expansions. The goal is to reduce the topological complexities of the larger edifices to a few simple parameters which can then be related to similar expressions for well-studied terrestrial and martian features.

  12. Astrobiology and Venus Exploration

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

    Venus has not traditionally been considered a promising target for Astrobiological exploration. We propose that Venus should be central to such an exploration program for several reasons. 1) Putting Earth life in context: Venus is the only other Earth-sized terrestrial planet that we know of, and certainly the only one we will have the opportunity to explore in the foreseeable future. Many geological and meteorological processes otherwise active only on Earth at present are currently active on Venus. For example, active volcanism is most likely responsible for maintaining the global cloud cover (Bullock and Grinspoon, 2001). Understanding the divergence of Earth and Venus is central to understanding the limits of habitability in the inner regions of habitable zones around solar-type stars. Thus Venus presents us with a unique opportunity for putting the bulk properties, evolution and ongoing geochemical processes of Earth in a wider context. 2) The possibility of extant life: Venus almost surely once had warm oceans. The evaporation of these oceans, and subsequent escape of hydrogen, most likely resulted in an oxygenated atmosphere. The duration of this phase is poorly understood, but during this time the terrestrial planets were not isolated. Rather, due to frequent impact transport, they represented a continuous environment for early microbial life. Life, once established in the early oceans of Venus, may have migrated to the clouds which, on present day Venus, may represent a habitable niche. Though highly acidic, this aqueous environment enjoys moderate temperatures, surroundings far from chemical equilibrium, and potentially useful radiation fluxes. Observations of unusual chemistry in the clouds, and particle populations that are not well characterized, suggest that this environment must be explored much more fully before biology can be ruled out. A sulfur-based metabolism for cloud-based life on Venus has recently been proposed (Schulze-Makuch et al., 2004

  13. The Recent Evolution of Climate on Venus

    NASA Astrophysics Data System (ADS)

    Bullock, Mark A.; Grinspoon, David H.

    2001-03-01

    The present climate of Venus is controlled by an efficient carbon dioxide-water greenhouse effect and by the radiative properties of its global cloud cover. Both the greenhouse effect and clouds are sensitive to perturbations in the abundance of atmospheric water vapor and sulfur gases. Planetary-scale processes involving the release, transport, and sequestering of volatiles affect these abundances over time, driving changes in climate. We have developed a numerical model of the climate evolution of Venus. Atmospheric temperatures are calculated using a one-dimensional two-stream radiative-convective model that treats the transport of thermal infrared radiation in the atmosphere and clouds. These radiative transfer calculations are the first to utilize high-temperature, high-resolution spectral databases for the calculation of infrared absorption and scattering in Venus' atmosphere. We use a chemical/microphysical model of Venus' clouds to calculate changes in cloud structure that result from variations in atmospheric water and sulfur dioxide. Atmospheric abundances of water, sulfur dioxide, and carbon dioxide change under the influence of the exospheric escape of hydrogen, outgassing from the interior, and heterogeneous reactions with surface minerals. Radar images from the Magellan mission show that the surface of Venus has been geologically active on a global scale, yet its sparse impact cratering record is almost pristine. This geologic record on Venus is consistent with an epoch of rapid plains emplacement 600-1100 Myr ago. Our models show that intense volcanic outgassing of sulfur dioxide and water during this time would have resulted in the formation of massive sulfuric acid/water clouds and the cooling of the surface for 100-300 Myr. The thick clouds would have subsequently given way to high, thin water clouds as atmospheric sulfur dioxide was lost to reactions with the surface. Surface temperatures approaching 900 K would have been reached 200-500 Myr

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

    USGS Publications Warehouse

    Campbell, Bruce A.; Clark, David A.

    2006-01-01

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

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

    SciTech Connect

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

    2014-10-10

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

  16. Was Venus the first habitable world of our solar system?

    NASA Astrophysics Data System (ADS)

    Way, M. J.; Del Genio, Anthony D.; Kiang, Nancy Y.; Sohl, Linda E.; Grinspoon, David H.; Aleinov, Igor; Kelley, Maxwell; Clune, Thomas

    2016-08-01

    Present-day Venus is an inhospitable place with surface temperatures approaching 750 K and an atmosphere 90 times as thick as Earth's. Billions of years ago the picture may have been very different. We have created a suite of 3-D climate simulations using topographic data from the Magellan mission, solar spectral irradiance estimates for 2.9 and 0.715 Gya, present-day Venus orbital parameters, an ocean volume consistent with current theory, and an atmospheric composition estimated for early Venus. Using these parameters we find that such a world could have had moderate temperatures if Venus had a prograde rotation period slower than ~16 Earth days, despite an incident solar flux 46-70% higher than Earth receives. At its current rotation period, Venus's climate could have remained habitable until at least 0.715 Gya. These results demonstrate the role rotation and topography play in understanding the climatic history of Venus-like exoplanets discovered in the present epoch.

  17. Mars mission concepts and opportunities

    NASA Technical Reports Server (NTRS)

    Young, Archie C.

    1986-01-01

    Trajectory and mission requirement data are presented for Earth Mars opposition and conjunction class roundtrip flyby and stopover mission opportunities available between 1997 and 2045. The opposition class flyby mission uses direct transfer trajectories to and on return from Mars. The opposition class stopover mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg in order to reduce the propulsion requirement associated with the opposition class mission. The conjunction class mission minimizes propulsion requirements by optimizing the stopover time at Mars.

  18. Astrobiology and Venus exploration

    NASA Astrophysics Data System (ADS)

    Grinspoon, David H.; Bullock, Mark A.

    For hundreds of years prior to the space age, Venus was considered among the most likely homes for extraterrestrial life. Since planetary exploration began, Venus has not been considered a promising target for Astrobiological exploration. However, Venus should be central to such an exploration program for several reasons. At present Venus is the only other Earth-sized terrestrial planet that we know of, and certainly the only one we will have the opportunity to explore in the foreseeable future. Understanding the divergence of Earth and Venus is central to understanding the limits of habitability in the inner regions of habitable zones around solar-type stars. Thus Venus presents us with a unique opportunity for putting the bulk properties, evolution and ongoing geochemical processes of Earth in a wider context. Many geological and meteorological processes otherwise active only on Earth at present are currently active on Venus. Active volcanism most likely affects the climate and chemical equilibrium state of the atmosphere and surface, and maintains the global cloud cover. Further, if we think beyond the specifics of a particular chemical system required to build complexity and heredity, we can ask what general properties a planet must possess in order to be considered a possible candidate for life. The answers might include an atmosphere with signs of flagrant chemical disequilibrium and active, internally driven cycling of volatile elements between the surface, atmosphere and interior. At present, the two planets we know of which possess these characteristics are Earth and Venus. Venus almost surely once had warm, habitable oceans. The evaporation of these oceans, and subsequent escape of hydrogen, most likely resulted in an oxygenated atmosphere. The duration of this phase is poorly understood, but during this time the terrestrial planets were not isolated. Rather, due to frequent impact transport, they represented a continuous environment for early microbial

  19. Thermal evolution of Venus

    NASA Technical Reports Server (NTRS)

    Arkani-Hamed, J.; Toksoz, M. N.

    1984-01-01

    A modification of the Boussinesq fluid assumption is the basis of the present theory of three-dimensional and finite amplitude convection in a viscous spherical shell with temperature- and pressure-dependent physical parameters. The theory is applied to the definition of thermal evolution models for Venus which emphasize the effects of certain physical parameters on thermal evolution, rather than the specific thermal history of the planet. It is suggested that a significant portion of the present temperature in the mantle and surface heat flux of Venus is due to the decay of a high temperature that was established in the planet at the completion of its core formation, and that Venus has been highly convective over the course of its history, until about 0.5 Ga ago.

  20. Wireless Seismometer for Venus

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  1. Exploring Venus by Solar Airplane

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2001-01-01

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

  2. Venus - False Color Perspective of Sif and Gula Mons

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A portion of western Eistla Regio is shown in this three dimensional, computer-generated view of the surface of Venus. The viewpoint is at an elevation of 1.2 kilometers (0.75 mile) at a location 700 kilometers (435 miles) southeast of Gula Mons, the volcano on the right horizon. Gula Mons reaches 3 kilometers (1.8 miles) high and is located around 22 degrees north latitude and 359 degrees east longitude. Sif Mons, the volcano on the left horizon, has a diameter of 300 kilometers (186 miles) and a height of 2 kilometers (1.2 miles). Magellan imaging and altimetry data are combined to develop a three-dimensional computer view of the planet's surface. Simulated color based on color images from the Soviet Venera 13 and 14 spacecraft is added to enhance small-scale structure. This image was produced at JPL's Multimission Image Processing Laboratory by Eric De Jong, Jeff Hall and Myche McAuley. 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 a Magellan mapping cycle. The spacecraft completed its first mapping cycle and primary mission on May 15, 1991, and immediately began its second cycle. During the first cycle, Magellan mapped more than 80 percent of the planet's surface and the current and subsequent cycles of equal duration will provide complete mapping of Venus. Magellan was launched May 4, 1989, aboard the space shuttle Atlantis and went into orbit around Venus August 10, 1990.

  3. Ice caps on venus?

    PubMed

    Libby, W F

    1968-03-01

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

  4. The terraforming of Venus

    NASA Astrophysics Data System (ADS)

    Fogg, M. J.

    1987-12-01

    Methods are considered for the 'terraforming' modification of Venusian environmental conditions. It is noted that Venus cannot be terraformed by microbiological means alone, and that the massive importation of such materials as H2 from various regions of the solar system will have to be instituted; recent impact erosion research on atmospheres appears to preclude this as an option. More fundamentally, a decrease in the axial rotation period of Venus will be mandatory. Taking all factors into account, a project duration of 16,500 years, begining in 2500 AD, is envisioned. Human colonization could not begin before 19,000 AD.

  5. Lunar and Planetary Science XXXV: Venus

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Venus" included the following reports:Is It Possible to Detect Magnetic Materials on Venus with Bistatic Radar Probing?; Airfall Crater Deposits on the Surface of Venus: Do We See Them in the Venera Panoramas?; Rift System Architecture on Venus; Constraints on Deformation Belt Evolution on Venus; An Admittance Survey of Large Volcanoes on Venus: Implications for Volcano Growth; Crustal Thickening Above a Convecting Mantle with Application to Venus and Mars; Geological Mapping of Venus: Interpretation of Geologic History and Assessment of; Directional and Non-Directional Models; Ages of Venusian Ridge Belts Relative to Regional Plains; and Plumes as a Mechanism for Equilibrium Resurfacing of Venus.

  6. Does the face of Venus reveal whether she is Earth's fraternal twin or identical twin separated at birth?

    NASA Astrophysics Data System (ADS)

    Smrekar, S. E.

    2015-12-01

    Venus has nearly the same diameter and bulk composition as Earth, yet lacks a dynamo and evidence for plate tectonics. Its dense CO2 greenhouse creates a surface T of 460°C. Orbital and landed spectroscopy indicate a basaltic crust, with possible analogs to terrestrial continents. Radar images and altimetry reveal a volcanic surface, with regions of intense tectonic deformation, including rifts, mountain belts and large, intensely deformed plateaus. The sparse impact craters give a resurfacing age of 0.3-1 b.y. Their distribution cannot be distinguished from a random one, and fit models with either a single, rapid resurfacing pulse or ongoing resurfacing. Incorporating geologic constraints favors ongoing resurfacing. Ar isotope data indicate less interior outgassing than Earth, assuming a similar volatile inventory. Gravity and topography data, along with geologic features, provide evidence for ~10 large mantle plumes, similar to the number on Earth. The gravity/topography data at these hotspots suggests no low viscosity zone, perhaps implying a dry interior. Positive thermal emissivity from the Venus Express mission correlate with volcanic flows at several hotspots and can be interpreted as unweathered basalt, implying geologically recent activity. In addition, there are ~500 coronae, which are unique to Venus and likely form via small-scale upwelling, downwelling, or a combination. Many of the larger coronae may be sites of plume-induced subduction (see Davaille abstract), although subduction does not appear to create plates. I will discuss possible reasons Venus and Earth may have evolved differently and supporting evidence from surface observations. Did early impact or magma ocean history modify interior volatile or radiogenic content? Does high surface T and its effect on rheology and mineralogy inhibit plate tectonics? What is the evidence for a wet or dry interior? What could new missions tell us about these questions?

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    Studying the physical properties of Venus surface and subsurface structures is an important direction in the space research. The first aim of this contribution is to present some results of reanalysis of the bistatic radar and occultation experiments provided using Venera-9, 10 and 15, 16 satellites. Comparison is made with Magellan and Venus Express bistatic radar missions. Bistatic radio images of the Venus surface is compared with monostatic radio images obtained by the Soviet and USA orbiters. The second aim consists in introducing new methods for investigation of the layered structure of the Venus atmosphere and measuring parameters of Venus surface and subsurface structures using the bistatic radar technology. The first bistatic radar measurements with spatial resolution ~ 10-20 km have been carried out during autumn of 1975 year in the five Venus equatorial regions using the Venera-9 and 10 satellites. Small roughness and, in general, plain character of relief in the investigated regions have been revealed. In 1983, the satellites Venera 15 and 16 have carried out new bistatic radar experiments with spatial resolution in the interval 5 - 10 km. New information on the large-scale topography and roughness of small-scale relief has been obtained in Northern polar areas of the planet. Some features have been detected. 1. The significant variations of the reflectivity ~ 2-4 times were found in the first region. The second area of reflectivity magnitude was far below (by three - four times) the previously measured values in the equatorial regions of Venus. These significant reflectivity variations may be related to changes in the conductivity of the ground. 2. Extremely small values roughness with rms of slopes ~ 0.20 were recorded in the northern area. 3. Both the bending angle and the reflection coefficient were determined in the experiment from the measured frequency difference between the direct and the reflected signals as a function of time, using the

  8. Possible Signs of Fauna and Flora on Venus

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

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

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2015-11-01

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

  10. Venus on the Verge

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  11. Venus in 3D

    NASA Astrophysics Data System (ADS)

    Plaut, J. J.

    1993-08-01

    Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.

  12. Venus upper atmosphere structure

    NASA Astrophysics Data System (ADS)

    Keating, G. M.; Nicholson, J. Y.; Lake, L. R.

    1980-12-01

    Atmospheric densities of Venus were measured from the orbital decay of the Pioneer Venus from Dec. 9, 1978 to Aug. 7, 1979 near the 16 deg latitude between 140 and 190 km during the entire day. Comparative atmospheric densities on earth at 150 km are higher by a factor of 3.5 with only a 1% diurnal variation; an atmospheric composition, temperature, and density model based on the orbiter atmospheric drag (OAD) vertical structure is presented. The model shows that atomic oxygen is the major component in the Venus atmosphere above 145 km at night and above 160 km during the day with mixing ratios over 0.1 near 140 km; drag measurements indicate O concentrations from 1 x 10 to the 9th/cu cm in daytime to 3 x 10 to the 7th/cu cm at night. It is concluded that the neutral upper atmosphere of Venus is surprisingly insensitive to solar extreme UV variations and changes in the solar wind.

  13. Venus - Lessons for earth

    NASA Technical Reports Server (NTRS)

    Hunten, D. M.

    1992-01-01

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

  14. The Prodigal Sister - Venus

    NASA Astrophysics Data System (ADS)

    Barlow, Nadine G.

    1995-09-01

    If you think Venus is a hellhole now, be thankful you weren't there 500 million years ago. Those were the days, many planetary scientists believe, of apocalypse on our sister world: Volcanoes wracked the land, while greenhouse gases broiled the air. Is this the Earth's fate, too?

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

    PubMed

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

    2007-11-29

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

  16. Development of a Pioneer Venus expert scheduling system

    NASA Technical Reports Server (NTRS)

    Rosenthal, Donald A.; Jackson, Robert W.

    1988-01-01

    An Expert System has been developed to perform a substantial part of the science planning for NASA's Pioneer Venus spacecraft. The program performs functions that have been traditionally performed by operations personnel ('orbit builders'), and attempts to directly duplicate their methods and techniques. Output from the program is formatted to correspond to the previously hand-generated worksheets, in order to ease program validation as well as operator acceptance. Pioneer Venus mission operations are described in detail followed by a description of the expert system implementation.

  17. Fundamental issues in the geology and geophysics of Venus

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.; Head, J. W.

    1991-04-01

    A number of important and currently unresolved issues in the global geology and geophysics of Venus will be addressable with the radar imaging, altimetry, and gravity measurements now forthcoming from the Magellan mission. Among these are the global volcanic flux and the rate of formation of new crust; the global heat flux and its regional variations; the relative importance of localized hot spots and linear centers of crustal spreading to crustal formation and tectonics; and the planform of mantle convection on Venus and the nature of the interactions among interior convective flow, near-surface deformation, and magmatism.

  18. Prospective spacecraft for venus research: Venera-D design

    NASA Astrophysics Data System (ADS)

    Vorontsov, V. A.; Lokhmatova, M. G.; Martynov, M. B.; Pichkhadze, K. M.; Simonov, A. V.; Khartov, V. V.; Zasova, L. V.; Zelenyi, L. M.; Korablev, O. I.

    2011-12-01

    A new phase of Venus research has started in Russia; the Federal Space Program includes the Venera-D design with the launch of the spacecraft scheduled for 2016. The mission comprises an orbiter, a descent vehicle, and balloon probes. The balloon probes will be placed at different altitudes in the cloud layer and under the clouds, where they are intended to last for a long time in the atmosphere of Venus. The successful implementation of the design will allow solving of quite a number of scientific tasks for comparative planetology.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  20. Sampling the Cloudtop Region on Venus

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    The details of the cloud structure on Venus continue to be elusive. One of the main questions is the nature and identity of the ultraviolet absorber(s). Remote sensing observations from Venus Express have provided much more information about the ubiquitous cloud cover on Venus from both reflected and emitted radiation from Venus Monitoring Camera (VMC) and Visible InfraRed Imaging Spectrometer (VIRTIS) observations. Previously, only the Pioneer Venus Large Probe has measured the size distribution of the cloud particles, and other probes have measured the bulk optical properties of the cloud cover. However, the direct sampling of the clouds has been possible only below about 62 km, whereas the recent Venus Express observations indicate that the cloud tops extend from about 75 km in equatorial region to about 67 km in polar regions. To sample the cloud top region of Venus, other platforms are required. An unmanned aerial vehicle (UAV) has been proposed previously (Landis et al., 2002). Another that is being looked into, is a semi-buoyant aerial vehicle that can be powered using solar cells and equipped with instruments to not only sample the cloud particles, but also to make key atmospheric measurements - e.g. atmospheric composition including isotopic abundances of noble and other gases, winds and turbulence, deposition of solar and infrared radiation, electrical activity. The conceptual design of such a vehicle can carry a much more massive payload than any other platform, and can be controlled to sample different altitudes and day and night hemispheres. Thus, detailed observations of the surface using a miniature Synthetic Aperture Radar are possible. Data relay to Earth will need an orbiter, preferably in a low inclination orbit, depending on the latitude region selected for emphasis. Since the vehicle has a large surface area, thermal loads on entry are low, enabling deployment without the use of an aeroshell. Flight characteristics of such a vehicle have been

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  2. Pioneer Mars 1979 mission options

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  3. Venus tectonics: initial analysis from magellan.

    PubMed

    Solomon, S C; Head, J W; Kaula, W M; McKenzie, D; Parsons, B; Phillips, R J; Schubert, G; Talwani, M

    1991-04-12

    Radar imaging and altimetry data from the Magellan mission have revealed a diversity of deformational features at a variety of spatial scales on the Venus surface. The plains record a superposition of different episodes of deformation and volcanism; strain is both areally distributed and concentrated into zones of extension and shortening. The common coherence of strain patterns over hundreds of kilometers implies that many features in the plains reflect a crustal response to mantle dynamic processes. Ridge belts and mountain belts represent successive degrees of lithospheric shortening and crustal thickening; the mountain belts also show widespread evidence for extension and collapse both during and following crustal compression. Venus displays two geometrical patterns of concentrated lithospheric extension: quasi-circular coronae and broad rises with linear rift zones; both are sites of significant volcanism. No long, large-offset strike-slip faults have been observed, although limited local horizontal shear is accommodated across many zones of crustal shortening. In general, tectonic features on Venus are unlike those in Earth's oceanic regions in that strain typically is distributed across broad zones that are one to a few hundred kilometers wide, and separated by stronger and less deformed blocks hundreds of kilometers in width, as in actively deforming continental regions on Earth.

  4. Signs of hypothetical fauna of Venus

    NASA Astrophysics Data System (ADS)

    Ksanfomality, Leonid V.

    2014-04-01

    On March 1 and 5, 1982, experiments in television photography instrumented by the landers VENERA-13 and -14, yielded 37 panoramas (or their fragments) of the Venus surface at the landing site. Over the past 31 years, no similar missions have been sent to Venus. Using a modern technique the VENERA panoramas were re-examined. A new analysis of Venusian surface panoramas' details has been made. A few relatively large objects of hypothetical fauna of Venus were found with size ranging from a decimeter to half meter and with unusual morphology. Treated once again VENERA-14 panoramic images revealed `amisada' object about 15 cm in size possessing apparent terramorphic features. The amisada's body stands out with its lizard-like shape against the stone plates close by. The amisada can be included into the list of the most significant findings of the hypothetical Venusian fauna. The amisada's body show slow movements, which is another evidence of the Venusian fauna's very slow style of activity, which appears to be associated with its energy constraints or, and that is more likely, with the properties of its internal medium. The terramorphic features of the Venusian fauna, if they are confirmed, may point out at outstandingly important and yet undiscovered general laws of the animated nature on different planets.

  5. Venus transit 2004: An international education program

    NASA Astrophysics Data System (ADS)

    Mayo, L.; Odenwald, S.

    2003-04-01

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

  6. Venus - Simulated Color of Leda Planitia

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This false color Magellan image shows a portion of Leda Planitia (plains) in the northern hemisphere of Venus, centered at 41 degrees north latitude, 52 degrees east longitude. The area is 220 kilometers (135 miles) wide and 275 kilometers (170 miles) long. This image was produced from Magellan radar data collected in Cycle 2 of the mission. Cycle 2 was completed January 15, 1992. The area was not imaged during the first cycle because of superior conjunction when the sun was between the Earth and Venus, preventing communication with the spacecraft. This image contains examples of several of the major geologic terrains on Venus and illustrates the basic stratigraphy or sequence of geologic events. The oldest terrains appear as bright, highly-fractured or chaotic highlands rising out of the plains. This is seen in the upper left, or northwest, quadrant of the image. The chaotic highlands, sometimes called tessera, may represent older and thicker crustal material and occupy about 15 percent of the surface of Venus. The circular ring structure in the lower left of the image is probably an impact crater. This 40 kilometer (25 miles) diameter crater has been given a proposed name, Heloise, after the French physician who lived from about 1098 to 1164 A.D. The crater was formed by the impact of an asteroid sometime before the plains lavas embayed and covered the region. The plains surround and embay the fractured highland tessera. Plains are formed by fluid volcanic flows that may have once formed vast lava seas which covered all the low lying surfaces. Plains comprise more than 80 percent of the surface of Venus. The most recent activity in the region is volcanism that produced the radar bright flows best seen in the upper right quadrant of the image. Those flows are similar to the darker plains volcanics, but apparently have more rugged surfaces that more efficiently scatter the radar signal back to the spacecraft. Thus the geologic sequence is early fracturing of the

  7. Second Venus spacecraft set for launch

    NASA Technical Reports Server (NTRS)

    1978-01-01

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

  8. Tectonic connections to interior processes on Venus

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1992-01-01

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

  9. The Stability of Climate on Venus

    NASA Astrophysics Data System (ADS)

    Bullock, Mark Alan

    The present climate of Venus is controlled by an efficient carbon dioxide-water greenhouse effect and by the radiative properties of its global cloud cover. Both the greenhouse effect and clouds are sensitive to perturbations in the abundance of atmospheric water vapor and sulfur gases. Planetary-scale processes involving the transport and sequestering of volatiles affect these abundances over time, driving changes in climate. I have developed a numerical model of the climate evolution of Venus. Atmospheric temperatures are calculated using a one-dimensional two-stream radiative-convective model that treats the transport of thermal infrared radiation in the atmosphere and clouds. These radiative transfer calculations are the first to utilize high temperature, high resolution spectral databases for the calculation of infrared absorption and scattering in Venus' atmosphere. I use a chemical/microphysical model of Venus' clouds to calculate changes in cloud structure that result from variations in atmospheric water and sulfur dioxide. Atmospheric abundances of water, sulfur dioxide, and carbon dioxide change under the influence of the exospheric escape of hydrogen, outgassing from the interior, and heterogeneous reactions with surface minerals. Radar images from the Magellan mission show that the surface of Venus has been geologically active on a global scale, yet its sparse impact cratering record is almost pristine. This geological record on Venus is consistent with an epoch of rapid plains emplacement 600-1100 million years ago. My models show that intense volcanic outgassing of sulfur dioxide and water during this time would have resulted in the formation of massive sulfuric acid/water clouds and the cooling of the surface for about 300 million years. The thick clouds would have subsequently given way to high, thin water clouds as atmospheric sulfur dioxide was lost to reactions with the surface. Surface temperatures approaching 900 K would have been reached about

  10. Mission and vehicle sizing sensitivities

    NASA Technical Reports Server (NTRS)

    Young, Archie C.

    1986-01-01

    Representative interplanetary space vehicle systems are sized to compare and show sensitivity of the initial mass required in low Earth orbit to one mission mode and mission opportunity. Data are presented to show the requirements for Earth-Mars opposition and conjunction class roundtrip flyby and stopover mission opportunities available during the time period from year 1997 to year 2045. The interplanetary space vehicle consists of a spacecraft and a space vehicle acceleration system. Propellant boil-off for the various mission phases is given for the Lox/LH (Liquid Oxygen/Liquid Hydrogen) propulsion systems. Mission abort information is presented for the 1999 Venus outbound swingby trajectory, transfer profile.

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

    SciTech Connect

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

    1998-07-01

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

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

    SciTech Connect

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

    1990-05-01

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

  13. Planetary Ion fluxes in the Venus Wake

    NASA Astrophysics Data System (ADS)

    Pérez-de-Tejada, H.; Lundin, R.; Durand-Manterola, H.; Barabash, S.; Zhang, T. L.; Sauvaud, J. A.; Reyes-Ruiz, M.

    2012-09-01

    Measurements conducted with the ASPERA-4 instrument and the magnetometer of the Venus Express spacecraft show that the kinetic pressure of planetary O+ ions measured in the Venus wake can be significantly larger than the local magnetic pressure and, as a result, those ions are not being driven by magnetic forces but by the kinetic energy of the solar wind. Beams of planetary O+ ions with those properties have been detected in several orbits of the Venus Express through the wake as the spacecraft traverses by the noon-midnight plane along its near polar trajectory. Peak values of the kinetic pressure of the O+ ions are sufficient to produce superalfvenic flow conditions. It is suggested that such O+ ion beams are eroded from the magnetic polar regions of the Venus ionosphere where the solar wind carves out plasma channels that extend downstream from those regions. Issues related to the acceleration of planetary ions as the solar wind interacts with the Venus ionosphere are related to the energetics of the plasma. When the kinetic pressure of the particle populations involved in the interaction is smaller than the local magnetic pressure the latter will be dominant and hence the particles will follow trajectories dictated by the magnetic field. Such conditions should occur by the magnetic barrier that is formed over the dayside Venus ionosphere where the interplanetary magnetic fluxes pile up thus leading to enhanced values of the magnetic field intensity. Different conditions are expected when the kinetic pressure of the plasma is larger than the local magnetic pressure. In this case the latter will be convected by the particle fluxes as it occurs in the superalfvenic solar wind. Plasma conditions applicable to the planetary ions that stream in the Venus wake and that have been removed from the Venus ionosphere can be examined using the plasma and magnetic field data obtained from the Venus Express (VEX) measurements. A suitable example is provided by the plasma and

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Venus tessera terrain is a major, yet unsampled, tectonic unit on Venus characterized by multiple sets of intersecting compressional and extensional structures. Tessera terrain is temporally, morphologically, and perhaps also compositionally unique on Venus. Stratigraphic studies of tessera terrain establish that they consistently appear locally, and perhaps even globally, as the oldest material on a planet with an average surface crater retention age of ~500 million years. Thus, the tesserae provide the best chance to access rocks that are derived from the first 80% of the history of the planet, an era obscured by the emplacement of voluminous (presumably basaltic) plains. Analysis of Magellan imagery, topography and gravity data show that tessera terrain is characterized by higher strain rates and a thinner lithosphere than at present and thus records an extinct geodynamical era on Venus. Yet very little is understood about the number, morphology and stratigraphy of geologic units within tessera terrain, nor mass wasting processes operating on the surface. Improved radar imagery at the 5-25 m scale, and optical images below the clouds (<1 km) and at the surface will help assess the geologic processes operating in the pre-plains era. Such data products are also essential for judicious landing site selection, since tessera meter-scale roughness will limit landing site safety and sample access. Improved topography data are required to quantify the deformation recorded by ubiquitous tesserae structures that are finer than Magellan resolution. Tessera terrain is unsampled, but recent analyses of radiance from the surface at 1 micron using instruments on Venus Express and Galileo are consistent with felsic compositions for tesserae. Silicic compositions likely require both water and a plate recycling mechanism (e.g., subduction) for formation. The high D/H ratio of the Venus atmosphere is consistent with the loss of a significant inventory of water over the history of

  15. The new face of Venus

    NASA Astrophysics Data System (ADS)

    Stofan, E. R.

    1993-08-01

    The Magellan data on the Venus landscape which revealed volcanoes, shining mountains, relaxing plateaus, and craters on the surface of about 500 C, with an atmospheric pressure 90 times that of earth, are discussed. Venus is considered to be a planet that is both incredibly similar and dissimilar to earth. Venus might not exhibit plate tectonism but it might be dominated by catastrophes. The greenhouse around Venus has operated for at least the last 500 million years. The Magellan data revealed channels extending for thousands of kilometers, beautiful outflows surrounding impact craters, and odd volcanic constructs like the steep-sided domes.

  16. The new face of Venus

    NASA Technical Reports Server (NTRS)

    Stofan, Ellen R.

    1993-01-01

    The Magellan data on the Venus landscape which revealed volcanoes, shining mountains, relaxing plateaus, and craters on the surface of about 500 C, with an atmospheric pressure 90 times that of earth, are discussed. Venus is considered to be a planet that is both incredibly similar and dissimilar to earth. Venus might not exhibit plate tectonism but it might be dominated by catastrophes. The greenhouse around Venus has operated for at least the last 500 million years. The Magellan data revealed channels extending for thousands of kilometers, beautiful outflows surrounding impact craters, and odd volcanic constructs like the steep-sided domes.

  17. Aerobraking at Venus: A science and technology enabler

    NASA Astrophysics Data System (ADS)

    Hibbard, Kenneth; Glaze, Lori; Prince, Jill

    2012-04-01

    Venus remains one of the great unexplored planets in our solar system, with key questions remaining on the evolution of its atmosphere and climate, its volatile cycles, and the thermal and magmatic evolution of its surface. One potential approach toward answering these questions is to fly a reconnaissance mission that uses a multi-mode radar in a near-circular, low-altitude orbit of ∼400 km and 60-70° inclination. This type of mission profile results in a total mission delta-V of ∼4.4 km/s. Aerobraking could provide a significant portion, potentially up to half, of this energy transfer, thereby permitting more mass to be allocated to the spacecraft and science payload or facilitating the use of smaller, cheaper launch vehicles.Aerobraking at Venus also provides additional science benefits through the measurement of upper atmospheric density (recovered from accelerometer data) and temperature values, especially near the terminator where temperature changes are abrupt and constant pressure levels drop dramatically in altitude from day to night.Scientifically rich, Venus is also an ideal location for implementing aerobraking techniques. Its thick lower atmosphere and slow planet rotation result in relatively more predictable atmospheric densities than Mars. The upper atmosphere (aerobraking altitudes) of Venus has a density variation of 8% compared to Mars' 30% variability. In general, most aerobraking missions try to minimize the duration of the aerobraking phase to keep costs down. These short phases have limited margin to account for contingencies. It is the stable and predictive nature of Venus' atmosphere that provides safer aerobraking opportunities.The nature of aerobraking at Venus provides ideal opportunities to demonstrate aerobraking enhancements and techniques yet to be used at Mars, such as flying a temperature corridor (versus a heat-rate corridor) and using a thermal-response surface algorithm and autonomous aerobraking, shifting many daily ground

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

    NASA Technical Reports Server (NTRS)

    Wilson, J. H.

    1973-01-01

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

  19. Magmatic diversity on Venus: Constraints from terrestrial analog crystallization experiments

    NASA Astrophysics Data System (ADS)

    Filiberto, Justin

    2014-03-01

    Igneous diversity is common on terrestrial planets and has been experimentally investigated for the Earth and Mars, but only suggested for Venus. Since Venus and Earth are sister planets and have similar bulk chemistry, experiments on terrestrial basalts can place constraints on the formation of the Venera and Vega basalts. Furthermore, experimental results can suggest the types of magmas that should be present on Venus if processes of differentiation similar to those taking place within the Earth are occurring on Venus, as suggested by the Venera and Vega analyses. The interpretation of the Venera 13 analysis as an alkali basalt suggests deep partial melting of a carbonated source region; while the identification of Venera 14 and Vega 2 as tholeiites suggest relatively shallow melting of a hydrous lherzolitic or peridotite source region. The 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. Results from these crystallization experiments on tholeiitic terrestrial compositions can constrain the type and quality of data needed from future missions to determine the petrologic history of surface igneous rocks.

  20. Venus surface properties deduced from radar and radiometry

    NASA Technical Reports Server (NTRS)

    Ford, P. G.

    1989-01-01

    The brightness of surface features on side looking radar images of Venus is determined by many factors: the angles of incidence and reflection, polarization, surface geometry and composition, and so forth. The contribution from surface properties themselves can only be deduced by combining several types of measurement. For instance, without additional information, it is impossible to distinguish the effects of changes in surface roughness from those in dielectric constant. In common with the Moon and Mars, the surface of Venus appears to scatter radar waves in two ways: small-scale surface inhomogeneities, i.e., those smaller than the incident wavelength, depolarize and scatter the energy over a wide range of angles. The Pioneer Venus radar mapper experiment made three overlapping sets of measurements of the equatorial region of Venus from 15 deg S latitude to 45 deg N; the backscatter cross section at a range of incidence angles, the shape and intensity of radar echoes from the nadir, and the microwave brightness temperature of the surface. These techniques developed during the analysis of Pioneer Venus data will be used during the Magellan mission to extract measurements of surface slopes and dielectric constants over all areas covered by the SAR and altimeter antennae, with a resolution of about 10 km. A knowledge of the mechanisms that govern surface scattering will also be useful in the analysis of higher resolution side looking radar images, particularly in distinguishing the effects of changing roughness from those caused by a long range surface tilt or changing dielectric constant.

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  2. Impact craters on Venus

    NASA Technical Reports Server (NTRS)

    Schaber, G. G.

    1991-01-01

    Compared with volcanism and tectonism, impact cratering on Venus has played an overall minor role in sculpting the present-day landscape. The study of Venus impact craters is vital to help place the chronology of the geologic features on the surface in the context of the planet's geological evolution. The degradation of impact craters also provides information on surface and interior processes, particularly alteration by tectonism and volcanism. Through orbit 1422, Magellan mapped about 450 impact craters, with diameters ranging from 2 to 275 km, within an area of about 226 million sq km, or 49 percent of the planet's surface. These craters and their associated deposits show surprisingly little evidence of degradation at the 75 m/pixel resolution of the Magellan SAR. Remarkably few craters in the Magellan images appear to be in the process of being buried by volcanic deposits or destroyed by tectonic activity.

  3. Magellan unveils Venus

    SciTech Connect

    Lerner, E.J.

    1991-07-01

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

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

    NASA Astrophysics Data System (ADS)

    2003-05-01

    Mars has always fascinated human beings. No other planet has been visited so many times by spacecraft. And still, it has not been easy to unveil its secrets. Martian mysteries seem to have increased in quantity and complexity with every mission. When the first spacecraft were sent - the Mariner series in 1960s - the public was expecting an Earth ‘twin’, a green, inhabited planet full of oceans. Mariner shattered this dream by showing a barren surface. This was followed by the Viking probes which searched for life unsuccessfully in 1976. Mars appeared dry, cold and uninhabited: the Earth’s opposite. Now, two decades later, modern spacecraft have changed that view, but they have also returned more questions. Current data show that Mars was probably much warmer in the past. Scientists now think that Mars had oceans, so it could have been a suitable place for life in the past. “We do not know what happened to the planet in the past. Which process turned Mars into the dry, cold world we see today?” says Agustin Chicarro, ESA’s Mars Express project scientist. “With Mars Express, we will find out. Above all, we aim to obtain a complete global view of the planet - its history, its geology, how it has evolved. Real planetology!” Mars Express will reach the Red Planet by the end of December 2003, after a trip of just over six months. Six days before injection into its final orbit, Mars Express will eject the lander, Beagle 2, named after the ship on which Charles Darwin found inspiration to formulate his theory of evolution. The Mars Express orbiter will observe the planet and its atmosphere from a near-polar orbit, and will remain in operation for at least a whole Martian year (687 Earth days). Beagle 2 will land in an equatorial region that was probably flooded in the past, and where traces of life may have been preserved. The Mars Express orbiter carries seven advanced experiments, in addition to the Beagle 2 lander. The orbiter’s instruments have been

  5. Measurement of solar wind electron density and temperature in the shocked region of Venus and the density and temperature of photoelectrons within the ionosphere of Venus

    NASA Astrophysics Data System (ADS)

    Knudsen, William C.; Jones, Douglas E.; Peterson, Bryan G.; Knadler, Charles E.

    2016-08-01

    Presented herein are measurements of the solar wind electron number density and temperature near and within the bow shock of Venus. The measurements were made by the Pioneer Venus mission Orbiter Retarding Potential Analyzer operating in its suprathermal electron mode. The measurements are essentially point measurements. The spacecraft travels approximately 0.8 km during the 0.1 s time interval required to record a single I-V curve. The dual measurement of a density and temperature is obtained from one sweep by least squares fitting a mathematical Maxwellian expression to the I-V curve. The distance between successive measurements is approximately 100 km. In many orbits, when the spacecraft is crossing or traveling within the bow shock, the derived densities and temperatures (high density, high temperature (HDHT)) are large, densities of the order of 100 cm-3 and temperatures of the order of several hundred eV. We interpret these HDHT measurements as measurements in regions where the large, directed kinetic energy of the solar wind ions is being degraded into randomized, more thermal-like energy distributions of the electrons and ions through wave-particle interactions. The HDHT values define the electron energy distribution in the limited energy interval 0 to 50 eV. We assume that the underlying electron flux distributions are flat topped like those measured in the Earth's bow shock. We also report densities and temperatures of EUV produced photoelectron energy distributions measured within the ionosphere.

  6. Simulated Craters on Venus

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin; Cuzzi, Jeffrey N. (Technical Monitor)

    1995-01-01

    The thick atmosphere of Venus prevents all but the largest impactors from cratering the surface. The number of small craters on Venus provides an interesting, and statistically significant test of models for the disruption and deceleration of impacting bodies. Here we compare Monte Carlo simulated crater distributions to the observed crater distribution on Venus. The simulation assumes: (1) a power law mass distribution for impactors of the form N(sub cum) alpha m (exp-b) where b=0.8; (2) isotropic incidence angles; (3) velocity at the top of the atmosphere of 20 kilometers per second (more realistic velocity distributions are also considered); (4) Schmidt-Housen crater scaling, modified such that only the normal component of the impact velocity contributes to cratering, and using crater slumping as parameterized (5) and modern populations (60% carbonaceous, 40% stone, 3% iron) and fluxes of asteroids. We use our previously developed model for the disruption and deceleration of large bodies striking thick planetary atmospheres to calculate the impact velocity at the surface as a function of impactor mass, incident velocity, and incident angle. We use a drag coefficient c(sub d) =1; other parameters are as described in Chyba et al. We set a low velocity cutoff of 500 meters per second on crater-forming impacts. Venus's craters are nicely matched by the simulated craters produced by 700 million years of striking asteroids. Shown for comparison are the simulated craters produced by incident comets over the same period, where for comets we have assumed b=0.7 and a flux at 10(exp 14) g 30% that of asteroids. Systematic uncertainties in crater scaling and crater slumping may make the surface age uncertain by a factor of two.

  7. Three ages of Venus

    NASA Technical Reports Server (NTRS)

    Wood, Charles A.; Coombs, Cassandra R.

    1989-01-01

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

  8. Venus - Dead or alive?

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  9. Venus: dead or alive?

    PubMed

    Taylor, H A; Cloutier, P A

    1986-11-28

    In situ nightside electric field observations from the Pioneer Venus Orbiter have been interpreted as evidence of extensive lightning in the lower atmosphere of Venus. The scenario, including proposed evidence of clustering of lightning over surface highland regions, has encouraged the acceptance of currently active volcanic output as part of several investigations of the dynamics and chemistry of the atmosphere and the geology of the planet. However, the correlation between the 100-hertz electric field events attributed to lightning and nightside ionization troughs resulting from the interaction of the solar wind with the ionosphere indicates that the noise results from locally generated plasma instabilities and not from any behavior of the lower atmosphere. Furthermore, analysis of the spatial distribution of the noise shows that it is not clustered over highland topography, but rather occurs at random throughout the latitude and longitude regions sampled by the orbiter during the first 5 years of operation, from 1978 to 1984. Thus the electric field observations do not identify lightning and do not provide a basis for inferring the presence of currently active volcanic output. In the absence of known evidence to the contrary, it appears that Venus is no longer active. PMID:17778949

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

    NASA Astrophysics Data System (ADS)

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

    1999-01-01

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

  11. Radiative Energy Balance in the Venus Atmosphere

    NASA Astrophysics Data System (ADS)

    Titov, Dmitrij V.; Piccioni, Giuseppe; Drossart, Pierre; Markiewicz, Wojciech J.

    This chapter reviews the observations of the radiative fluxes inside and outside the Venusian atmosphere, along with the available data about the planetary energy balance and the distribution of sources and sinks of radiative energy. We also briefly address the role of the radiation on the atmospheric temperature structure, global circulation, thermodynamics, climate and evolution of Venus and compare the main features of radiative balance on the terrestrial planets. We describe the physics of the greenhouse effect as it applies to the evolution of the Venusian climate, concluding with a summary of outstanding open issues. The article is to a great extent based on the paper by Titov et al. [2007] expanded byincluding recent results from the Venus Express observations relevant to the topic.

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  13. Making the Venus Concept Watch 1.0

    NASA Astrophysics Data System (ADS)

    Balint, Tibor S.; Melchiorri, Julian P.

    2014-08-01

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

  14. Evaluation of Long Duration Flight on Venus

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Colozza, Anthony J.

    2006-01-01

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

  15. VEM on VERITAS - Retrieval of global infrared surface emissivity maps of Venus and expectable retrieval uncertainties

    NASA Astrophysics Data System (ADS)

    Kappel, David; Arnold, Gabriele; Haus, Rainer; Helbert, Jörn; Smrekar, Suzanne; Hensley, Scott

    2016-04-01

    Even though Venus is in many respects the most Earth-like planet we know today, its surface composition and geology are not well understood yet. The major obstacle is the extremely dense, hot, and opaque atmosphere that complicates both in situ measurements and infrared remote sensing, the wavelength range of the latter often being the range of choice due to its coverage of many spectral properties diagnostic to the surface material's composition and texture. Thermal emissions of the hot surface depend on surface temperature and on spectral surface emissivity. As this emitted radiation wells upward, it is strongly attenuated through absorption and multiple scattering by the gaseous and particulate components of the dense atmosphere, and it is superimposed by thermal atmospheric emissions. While surface information this way carried to space is completely lost in the scattered sunlight on the dayside, a few narrow atmospheric transparency windows around 1 μm allow the sounding of the surface with nightside measurements. The successfully completed VEX ('Venus Express') mission, although not dedicated to surface science, enabled a first glimpse at much of the southern hemisphere's surface through the nightside spectral transparency windows covered by VIRTIS-M-IR ('Visible and InfraRed Thermal Imaging Spectrometer, Mapping channel in the IR', 1.0-5.1 μm). Two complementary approaches, a fast semi-empiric technique on the one hand, and a more fundamental but resource-intensive method based on a fully regularized Bayesian multi-spectrum retrieval algorithm in combination with a detailed radiative transfer simulation program on the other hand, were both successfully applied to derive surface emissivity data maps. Both methods suffered from lack of spatial coverage and a small SNR as well as from surface topography maps not sufficiently accurate for the definition of suitable boundary conditions for surface emissivity retrieval. The recently proposed VERITAS mission

  16. Ballistic mode Mercury orbiter mission opportunity handbook

    NASA Technical Reports Server (NTRS)

    Hollenbeck, G. R.; Roos, D. G.; Lewis, P. S.

    1973-01-01

    Significant payloads in Mercury orbit can be achieved through use of high-thrust, chemical propulsion systems on ballistic trajectories. Interplanetary trajectory characteristics are presented, for Venus swingbys to Mercury, were multiple revolutions about the sun are allowed on each leg to provide low energy mission in 1977, 1980, 1985 and 1988. Guidance and navigation results are shown for each opportunity. Additionally, the use of midcourse maneuvers and multiple Venus swingbys are explored as means of further reducing the energy requirements.

  17. Russian mission Venera-D - new conception

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  18. The downward flux of O(+) over the nightside of Venus

    NASA Technical Reports Server (NTRS)

    Brannon, J. J.; Fox, J. L.

    1994-01-01

    We have constructed a map of the downward flux of O(+) over the nightside of Venus at high and low solar activities through a combination of modeling and analysis of Pioneer Venus ion mass spectrometer data. O(+) density profiles were obtained for almost 40 inbound or outbound segments of orbits from the first 2 years of the mission and about 40 more in the recent reentry phase of the mission. We have determined the nearly linear relationship between the 0(+) maximum density and the downward O(+) flux for several solar zenith angles and local times by constructing models of the nightside ionosphere of Venus for a range of downward ion fluxes at the upper boundaries. We find that the largest downward fluxes occur near the terminators, and the fluxes fall off sharply toward the antisolar point. Although the standard deviations in the data are large, there is a suggestion of a local maximum near 155 deg, and the location of this maximum correlates fairly well with structure in the peak electron density as a function of solar zenith angle reported for the Pioneer Venus radio occulation experiment. The average downward ion flux is inferred to be about 1.7 x 10(exp 8)/sq cm/sec over the nightside hemisphere at solar maximum and a factor of 7 less at moderately low solar activity.

  19. Technology development for long-lived Venus landers.

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

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

  20. Observed correlation of Venus topography with the zonal wind and albedo at cloud top level: the role of stationary gravity waves.

    NASA Astrophysics Data System (ADS)

    Bertaux, Jean-Loup; Khatunstsev, Igor; Hauchecorne, Alain; Markiewicz, Wojtek; Emmanuel, Marcq; Sébastien, Lebonnois; Marina, Patsaeva; Alex, Turin; Anna, Fedorova

    2016-04-01

    Based on the analysis of UV images (at 365 nm) of Venus cloud top (altitude 67±2 km) collected with VMC (Venus Monitoring Camera) on board Venus Express (VEX), it is found that the zonal wind speed south of the equator (from 5°S to 15°s) shows a conspicuous variation (from -101 to -83 m/s) with geographic longitude of Venus, correlated with the 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. These waves can propagate up to cloud top level, break there and transfer their momentum to the zonal flow. Such upward propagation of gravity waves and influence on the wind speed vertical profile was shown to play an important role in the middle atmosphere of the Earth by Lindzen [1981], but is not reproduced in a current GCM of Venus atmosphere. Consistent with present findings, the two VEGA mission balloons experienced a small, but significant, difference of westward velocity, at their 53 km floating altitude. The albedo at 365 nm varies also with longitude and latitude in a pattern strikingly similar in the low latitude regions to a recent map of cloud top H2O [Fedorova et al., 2015], in which a lower UV albedo is correlated with increased H2O. We argue that H2O enhancement is the sign of upwelling, suggesting that the UV absorber is also brought to cloud top by upwelling.

  1. Venus clouds: structure and composition.

    PubMed

    Young, A T

    1974-02-01

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

  2. Venus clouds: test for hydrocarbons.

    PubMed

    Plummer, W T

    1969-03-14

    Infrared reflection spectra of hydrocarbon clouds and frosts now give a critical test of Velikovsky's prediction that Venus is surrounded by a dense envelope of hydrocarbon clouds and dusts. Venus does not exhibit an absorption feature near 2.4 microns, although such a feature is prominent in every hydrocarbon spectrum observed.

  3. The thermal conditions of Venus

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  4. Venus Atmospheric Maneuverable Platform (VAMP)

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    VAMP is a long lived, semi-buoyant, atmospheric “rover” that deploys in orbit, enters the Venus atmosphere and flies in the Venus atmosphere between 55 and 70 km for up to one year as a platform to address VEXAG goals I.A, I.B, and I.C.

  5. Pioneer Venus radar mapper experiment

    USGS Publications Warehouse

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

    1979-01-01

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

  6. Plasma sheets in induced magnetospheres of Mars and Venus

    NASA Astrophysics Data System (ADS)

    Dubinin, Eduard; Fraenz, Markus; Woch, Joahim; Zhang, Tielong; Wei, Yong; Fedorov, Andrei; Barabash, Stas; Lundin, Rickard

    2013-04-01

    Mars and Venus have no a global intrinsic field and solar wind interacts directly with their conductive ionospheric shells producing the induced magnetospheres with magnetic tails. Plasma sheet is the region in the tail where the magnetic field tensions transfer the momentum back to the ionospheric plasmas which escape the planets. It is one of the main loss channels for the planetary ions. Mars Express and Venus Express have provided a wealth of the data on properties of the induced magnetic tails and plasma sheets. We will discuss their main characteristics including mechanisms of ion energization and their control by solar wind and the interplanetary magnetic field variations.

  7. Magellan: mission summary.

    PubMed

    Saunders, R S; Pettengill, G H

    1991-04-12

    The Magellan radar mapping mission is in the process of producing a global, high-resolution image and altimetry data set of Venus. Despite initial communications problems, few data gaps have occurred. Analysis of Magellan data is in the initial stages. The radar system data are of high quality, and the planned performance is being achieved in terms of spatial resolution and geometric and radiometric accuracy. Image performance exceeds expectations, and the image quality and mosaickability are extremely good. Future plans for the mission include obtaining gravity data, filling gaps in the initial map, and conducting special studies with the radar.

  8. Ion escape from Venus using statistical distribution functions

    NASA Astrophysics Data System (ADS)

    Nordstrom, T.; Stenberg, G.; Nilsson, H.; Barabash, S.; Futaana, Y.

    2012-04-01

    We use more than three years of data from the ASPERA-4 instrument onboard Venus Express to compile statistical distribution functions of ion flux in and around induced magnetosphere of Venus. We present samples of statistical distribution functions, as well average flux patterns in the near Venus space based on the statistical distribution functions. The statistical distribution functions allows for a compensation of biased sampling regarding both position and angular coverage of the instrument. Protons and heavy ions (mass/charge > 16) are the major ion species escaping from Venus. The escape is due to acceleration of planetary ions by energy transfer from the solar wind. The ion escape appears to exclusively take place in the induced magnetotail region and no heavy ions are present in the magnetosheath. Protons of solar wind origin are travelling around the planet and penetrating the tail, resulting in a mix of planetary and solar wind protons inside the induced magnetosphere boundary. The escape rates of ions inside the tail agree with results from recent published studies, where other analysis methods have been used. We also compare our results for Venus with a recent study of ion escape from Mars, where the same analysis method has been applied to data from the ASPERA-3 instrument on Mars Express. Both Mars and Venus are unmagnetized planets and are expected to interact similarly with the solar wind. On Mars the heavy ions are seen escaping in both the magnetosheath and tail regions as opposed to Venus where escape only takes place inside the tail. A possible explanation is that the magnetosphere of Mars is smaller compared to the ion gyroradius, making it easier for the ions to pass through the induced magnetosphere boundary. On both planets the escape rates of heavy ions in the tail are constant with increasing tail distance, verifying that the ions are leaving the planet in this region.

  9. VENUS-2 Experimental Benchmark Analysis

    SciTech Connect

    Pavlovichev, A.M.

    2001-09-28

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

  10. Non-Cooled Power System for Venus Lander

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  11. Survey of the spectral properties of turbulence in the solar wind, the magnetospheres of Venus and Earth, at solar minimum and maximum

    NASA Astrophysics Data System (ADS)

    Echim, Marius M.

    2014-05-01

    In the framework of the European FP7 project STORM ("Solar system plasma Turbulence: Observations, inteRmittency and Multifractals") we analyze the properties of turbulence in various regions of the solar system, for the minimum and respectively maximum of the solar activity. The main scientific objective of STORM is to advance the understanding of the turbulent energy transfer, intermittency and multifractals in space plasmas. Specific analysis methods are applied on magnetic field and plasma data provided by Ulysses, Venus Express and Cluster, as well as other solar system missions (e.g. Giotto, Cassini). In this paper we provide an overview of the spectral properties of turbulence derived from Power Spectral Densities (PSD) computed in the solar wind (from Ulysses, Cluster, Venus Express) and at the interface of planetary magnetospheres with the solar wind (from Venus Express, Cluster). Ulysses provides data in the solar wind between 1992 and 2008, out of the ecliptic, at radial distances ranging between 1.3 and 5.4 AU. We selected only those Ulysses data that satisfy a consolidated set of selection criteria able to identify "pure" fast and slow wind. We analyzed Venus Express data close to the orbital apogee, in the solar wind, at 0.72 AU, and in the Venus magnetosheath. We investigated Cluster data in the solar wind (for time intervals not affected by planetary ions effects), the magnetosheath and few crossings of other key magnetospheric regions (cusp, plasma sheet). We organize our PSD results in three solar wind data bases (one for the solar maximum, 1999-2001, two for the solar minimum, 1997-1998 and respectively, 2007-2008), and two planetary databases (one for the solar maximum, 2000-2001, that includes PSD obtained in the terrestrial magnetosphere, and one for the solar minimum, 2007-2008, that includes PSD obtained in the terrestrial and Venus magnetospheres and magnetosheaths). In addition to investigating the properties of turbulence for the minimum

  12. Ultra-Low-Frequency Waves at Venus and Mars

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.

    2016-02-01

    Mars and Venus have no global magnetic field. The solar wind interacts directly with their ionospheres and atmospheres, inducing magnetospheres by a pileup of the interplanetary magnetic field. The first measurements of the ultra-low-frequency activity on Mars were made by the Phobos-2 spacecraft. This chapter investigates the wave observations recently supplied by the Mars Global Surveyor, Venus Express, and Mars Express. Coherent wave structures are a typical feature of the Martian magnetosheath. It is likely that the periodic compressional waves generated upstream of the bow shock are transported to the magnetosheath. At Venus, there has often been observed a penetration of the field oscillations downward to the ionosphere. Periodic oscillations of the escaping oxygen ions were typically observed in the Martian tail by MEX. It seems reasonable to suggest that the observed oscillations take their origin in the foreshock/magnetosheath and then propagate to the ionosphere and further to the tail.

  13. Solar Wind Driven Plasma Fluxes from the Venus Ionosphere

    NASA Astrophysics Data System (ADS)

    Perez De Tejada, H. A.; Lundin, R. N.; Zhang, T.; Sauvaud, J. A.; Reyes-Ruiz, M.

    2012-12-01

    SOLAR WIND DRIVEN PLASMA FLUXES FROM THE VENUS IONOSPHERE H. Pérez-de-Tejada (1), R. Lundin (2), H. Durand-Manterola (1), S. Barabash (2), T. L. Zhang (3), J. A., Sauvaud (4), and M. Reyes-Ruiz (5) 1 - Institute of Geophysics, UNAM, México, D. F. 2 - Swedish Institute of Space Physics, Kiruna, Sweden 3 - Space Research Institute, Graz, Austria 4 - CESR, Toulouse, France 5 - Institute of Astronomy, UNAM, Ensenada, México Measurements conducted with the ASPERA-4 instrument and the magnetometer of the Venus Express spacecraft show that the kinetic pressure of planetary O+ ion fluxes measured in the Venus wake can be significantly larger than the local magnetic pressure and, as a result, those ions are not being driven by magnetic forces but by the kinetic energy of the solar wind. Beams of planetary O+ ions with those properties have been detected in several orbits of the Venus Express through the wake as the spacecraft traverses by the noon-midnight plane along its near polar trajectory. The momentum flux of the O+ ions leads to superalfvenic flow conditions. It is suggested that such O+ ion beams are produced in the vicinity of the magnetic polar regions of the Venus ionosphere where the solar wind erodes the local plasma leading to plasma channels that extend downstream from those regions.

  14. Venus atmosphere and extreme surface topography

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  15. Exospheric Temperature Estimation and Atmospheric Loss: a Comparative Study of Mars and Venus

    NASA Astrophysics Data System (ADS)

    Kazeminejad, S.

    2005-03-01

    The heating of the thermospheres and the formation of the ionospheres of terrestrial planets like Venus, Earth and Mars are mainly controlled by the solar X-ray and extreme ultraviolet radiation (0.1 - 100 nm). The current estimates of the Martian exosphere temperature (in the order of about 300-350 K) are based on hydrogen Lyman-alpha measurements. There is much evidence however, that these exospheric temperature estimates are too high. The reason for that comes mainly from to the fact that hot neutral hydrogen particles may have contaminated the neutral hydrogen. This study compares the ionospheric data obtained by the Mars Global Surveyor spacecraft with previous ionospheric data obtained by observations of former spacecraft missions. As the various data sets were obtained during different solar activity periods, it was planned to study the behavior of the dependence between the neutral temperature in the thermosphere obtained from a Chapman ionospheric profile near the ionospheric peak, and the solar 10.7 cm radio flux (F10.7). The estimations of this investigation clearly show that the exospheric temperature of Mars does not exceed a value of about 240 K, which is confirmed by inferred data of the Mars Global Surveyor aerobraking experiment. These results were compared to known observations (measurements of ionospheric profiles, F10.7 flux, and neutral gas temperatures at the Exobase level) on Venus. Furthermore the importance of these temperature estimations for the escape of hydrogen from the planets atmosphere are investigated and calculated. This study provides important results in the field of comparative planetology as it helps to obtain a good estimation of the Martian Exobase temperature, which so far (in contrast to Venus) has not been directly measured. This study is performed in the framework of the Mars Express participation of the Institute for Geophysics Astronomy and Meteorology (IGAM) of the Karl-Franzens University Graz/Austria and the Space

  16. Transition Parameter applied to boundaries at Venus

    NASA Astrophysics Data System (ADS)

    Guymer, Gemma; Grande, Manuel; Fraenz, Marcus; Barabash, Stas; Zhang, Tielong; Pinter, Balazs

    2015-04-01

    We have used a transition parameter to characterise magnetospheric boundaries at Venus. The technique allows sparsely sampled data to be related to a variable and rapidly moving structure, such as the Bow shock, Magnetic Pile-up boundary or Ion Composition boundary. The solar minimum in 2009 was one of the lowest on record, and by 2006 minimum conditions were already in place. Utilising the ASPERA-4 Ion Mass Analyzer data and the paired magnetometers on board Venus Express the relation between the ions and flux ropes are investigated, in order to determine whether they a part of the replenishment or loss of the Venusian atmosphere. First, by using the magnetometer to identify the flux rope in the ionosphere Wei H.Y. (2006 -personal communication) and then by using the IMA to observe coincident composition changes. The altitude of ropes is dependent on the time spent in the ionosphere, with older ropes increasing weight and dropping weight. However, the occurrence of flux ropes and a mixed populations of ionospheric and solar wind ions is coincidental. Venus boundaries are examined during 2007, and 2011 / 2012 going toward solar maximum. A new use of the transition parameter is put forward; to aid with boundary placement. The bow shock is located with an automatic algorithm and this is then compared with previous models, giving a sense of Venus reaction to solar activity. It is shown that the bow shock position is largely unchanged. The ion composition boundary and the magnetic pile-up boundary are also located. They coincide to within an ion sampling period, but transition parameter analysis reveals that they are not coincident, with the ion composition boundary inside the pileup boundary.

  17. Venus - a mystery unresolved

    NASA Astrophysics Data System (ADS)

    Baum, R.

    1997-12-01

    All brightness, but no detail. Overall this is widely considered to be the most reliable estimate the visual observer can ever give of the telescopic appearance of Venus; as John Herschel remarked, we notice in it only '...a uniform brightness, in which sometimes we may indeed fancy, or perhaps more than fancy, brighter or obscurer portions.' To a degree this is true, but it fails uniquely to take into account hazy intricacies that become visible when the contrast between planet and sky is subdued.

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

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1980-12-01

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

  20. Venus: A World of Water and Life

    NASA Astrophysics Data System (ADS)

    Ditkof, J. F.

    2012-12-01

    Author: John Ditkof Institution: University Wisconsin-Madison Amphiboles that contain the hydroxide ion form only in the presence of water and this fact has become the way for scientists to prove that Venus was once a water world. Though, Tremolite is considered the main mineral to look for, it requires life that is analogous to the ancient life here on Earth for it to form. Dolomite is the main ingredient for the formation of this low grade metamorphic mineral and without it would be very difficult for Tremolite to form, unless there is another process that is unknown to science. Venus is known to have extensive volcanic features (over 1600 confirmed shield volcanoes dot its surface) and with little erosion taking place; a mineral that is associated with volcanism and forms only in the presence of water should be regarded as the main goal. Hornblende can form via volcanism or a metamorphic process but requires water for initial formation. The European Space Agency is currently trying to determine whether or not the continents on Venus' surface are made of granite, as they argue granite requires water for formation. Either way, computer models suggest that any oceans that formed on the surface would have lasted at best 2 billion years, as the surface is estimated to be only 800 million years old, any hornblende that would have formed is more than likely going to be deep underground. To find this mineral, as well as others, it would require a mission that has the ability to drill into the surface, as the easiest place to do this would be on the mountain peaks in the Northern Hemisphere on the Ishtar Terra continent. Through the process of uplift, any remaining hornblende may have been exposed or very near exposed to the surface. Do to the amount of fluorine in the atmosphere and the interaction between this and the lithosphere, the hydroxyl ions may have been replaced with fluorine turning the hornblende into the more stable fluoro-hornblende. To further add to the

  1. Modelling the radiance spectra from the atmosphere of Venus - analysis the structure of Venusian clouds

    NASA Astrophysics Data System (ADS)

    Blecka, M. I.

    Venusian clouds makes the major contribution to attenuating incident solar radiation and to the thermal state of the lower atmosphere The clouds and haze are mainly composed of sulphuric acid aerosols and some other components but the nature and structure of clouds is not completely clear Numerical modeling is necessary to better understand the radiative processes and recognize optical characteristics of aerosols in the atmosphere Simulations are also useful to interpret the remote sensing data The interpretation of spectroscopic data is not straightforward because observed spectra are the results of a combination of different contributions e g radiation transmitted scattered and emitted in the atmosphere Presented work is directly connected with visible and infrared spectroscopic observations during Venus Express mission PFS and VIRTIS The main purpose of the paper is to simulate the total directional radiance at the top of the atmosphere by means of an radiation transfer model In the paper we show the examples of synthetic spectra of night and day side of Venus

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-06-23

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

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

    USGS Publications Warehouse

    Ivanov, Mikhail A.; Head, James W.

    2006-01-01

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

  6. Naming the newly found landforms on Venus

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  7. Progress report on VENUS

    SciTech Connect

    Leitner, Matthaeus A.; Leitner, Daniela; Abbott, Steve R.; Taylor, Clyde E.; Lyneis, Claude

    2002-09-03

    The construction of VENUS, a next generation superconducting Electron Cyclotron Resonance ion source designed to operate at 28 GHz, is complete. The cryostat including the superconducting magnet assembly was delivered in September 2001. During acceptance tests, the superconducting magnets produced an axial magnetic field strength of 4T at injection, 3T at extraction, and a radial field strength of 2T at the plasma chamber wall without any quenches. These fields are sufficient for optimum operation at 28 GHz. The cryogenic system for VENUS has been designed to operate at 4.2 K with two cryocoolers each providing up to 45 W of cooling at 50 K and 1.5 W at 4 K in a closed loop mode without further helium transfers. However, during the acceptance tests an excessive heat leak of about 3W was measured. In addition, the liquid helium heat exchanger did not work properly and had to be redesigned. The cryogenic system modifications will be described. In addition, an update on the installation of the ion source and its beam line components will be given.

  8. Hemispheric View of Venus Centered at 270 Degrees East Longitude

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 270 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one hemisphere of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.

  9. Hemispheric View of Venus Centered at 180 Degrees East Longitude

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 180 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one hemisphere of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.

  10. Hemispheric View of Venus Centered at 0 Degrees East Longitude

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 0 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one hemisphere of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.

  11. Hemispheric View of Venus Centered at 90 Degrees East Longitude

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 90 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one hemisphere of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.

  12. Venus - A total mass estimate

    NASA Technical Reports Server (NTRS)

    Sjogren, W. L.; Trager, G. B.; Roldan, G. R.

    1990-01-01

    Reductions of four independent blocks of Pioneer Venus Orbiter Doppler radio tracking data have produced very consistent determinations of the GM of Venus (the product of the universal gravitational constant and total mass of Venus). These estimates have uncertainties that are significantly smaller than any values published to date. The value of GM is also consistent with previously published results in that it falls within their one-sigma uncertainties. The value of 324858.60 + or - 0.05 cu km/sec sq is the best estimate.

  13. Venus-Earth-Mars: Comparative Climatology and the Search for Life in the Solar System

    NASA Astrophysics Data System (ADS)

    Launius, Roger D.

    2012-09-01

    Both Venus and Mars have captured the human imagination during the twentieth century as possible abodes of life. Venus had long enchanted humans - all the more so after astronomers realized it was shrouded in a mysterious cloak of clouds permanently hiding the surface from view. It was also the closest planet to Earth, with nearly the same size and surface gravity. These attributes brought myriad speculations about the nature of Venus, its climate, and the possibility of life existing there in some form. Mars also harbored interest as a place where life had or might still exist. Seasonal changes on Mars were interpreted as due to the possible spread and retreat of ice caps and lichen-like vegetation. A core element of this belief rested with the climatology of these two planets, as observed by astronomers, but these ideas were significantly altered, if not dashed during the space age. Missions to Venus and Mars revealed strikingly different worlds. The high temperatures and pressures found on Venus supported a "runaway greenhouse theory," and Mars harbored an apparently lifeless landscape similar to the surface of the Moon. While hopes for Venus as an abode of life ended, the search for evidence of past life on Mars, possibly microbial, remains a central theme in space exploration. This survey explores the evolution of thinking about the climates of Venus and Mars as life-support systems, in comparison to Earth.

  14. Venus-Earth-Mars: Comparative Climatology and the Search for Life in the Solar System

    PubMed Central

    Launius, Roger D.

    2012-01-01

    Both Venus and Mars have captured the human imagination during the twentieth century as possible abodes of life. Venus had long enchanted humans—all the more so after astronomers realized it was shrouded in a mysterious cloak of clouds permanently hiding the surface from view. It was also the closest planet to Earth, with nearly the same size and surface gravity. These attributes brought myriad speculations about the nature of Venus, its climate, and the possibility of life existing there in some form. Mars also harbored interest as a place where life had or might still exist. Seasonal changes on Mars were interpreted as due to the possible spread and retreat of ice caps and lichen-like vegetation. A core element of this belief rested with the climatology of these two planets, as observed by astronomers, but these ideas were significantly altered, if not dashed during the space age. Missions to Venus and Mars revealed strikingly different worlds. The high temperatures and pressures found on Venus supported a “runaway greenhouse theory,” and Mars harbored an apparently lifeless landscape similar to the surface of the Moon. While hopes for Venus as an abode of life ended, the search for evidence of past life on Mars, possibly microbial, remains a central theme in space exploration. This survey explores the evolution of thinking about the climates of Venus and Mars as life-support systems, in comparison to Earth. PMID:25371106

  15. Venus-Earth-Mars: comparative climatology and the search for life in the solar system.

    PubMed

    Launius, Roger D

    2012-09-19

    Both Venus and Mars have captured the human imagination during the twentieth century as possible abodes of life. Venus had long enchanted humans-all the more so after astronomers realized it was shrouded in a mysterious cloak of clouds permanently hiding the surface from view. It was also the closest planet to Earth, with nearly the same size and surface gravity. These attributes brought myriad speculations about the nature of Venus, its climate, and the possibility of life existing there in some form. Mars also harbored interest as a place where life had or might still exist. Seasonal changes on Mars were interpreted as due to the possible spread and retreat of ice caps and lichen-like vegetation. A core element of this belief rested with the climatology of these two planets, as observed by astronomers, but these ideas were significantly altered, if not dashed during the space age. Missions to Venus and Mars revealed strikingly different worlds. The high temperatures and pressures found on Venus supported a "runaway greenhouse theory," and Mars harbored an apparently lifeless landscape similar to the surface of the Moon. While hopes for Venus as an abode of life ended, the search for evidence of past life on Mars, possibly microbial, remains a central theme in space exploration. This survey explores the evolution of thinking about the climates of Venus and Mars as life-support systems, in comparison to Earth.

  16. Venus-Earth-Mars: comparative climatology and the search for life in the solar system.

    PubMed

    Launius, Roger D

    2012-01-01

    Both Venus and Mars have captured the human imagination during the twentieth century as possible abodes of life. Venus had long enchanted humans-all the more so after astronomers realized it was shrouded in a mysterious cloak of clouds permanently hiding the surface from view. It was also the closest planet to Earth, with nearly the same size and surface gravity. These attributes brought myriad speculations about the nature of Venus, its climate, and the possibility of life existing there in some form. Mars also harbored interest as a place where life had or might still exist. Seasonal changes on Mars were interpreted as due to the possible spread and retreat of ice caps and lichen-like vegetation. A core element of this belief rested with the climatology of these two planets, as observed by astronomers, but these ideas were significantly altered, if not dashed during the space age. Missions to Venus and Mars revealed strikingly different worlds. The high temperatures and pressures found on Venus supported a "runaway greenhouse theory," and Mars harbored an apparently lifeless landscape similar to the surface of the Moon. While hopes for Venus as an abode of life ended, the search for evidence of past life on Mars, possibly microbial, remains a central theme in space exploration. This survey explores the evolution of thinking about the climates of Venus and Mars as life-support systems, in comparison to Earth. PMID:25371106

  17. Venus lower atmospheric composition: preliminary results from pioneer venus.

    PubMed

    Hoffman, J H; Hodges, R R; McElroy, M B; Donahue, T M; Kolpin, M

    1979-02-23

    Initial examination of data from the neutral mass spectrometer on the Pioneer Venus sounder probe indicates that the abundances of argon-36, argon-38, and neon-20 in the Venus atmosphere are much higher than those of the corresponding gases in Earth's atmosphere, although the abundance of radiogenic argon-40 is apparently similar for both planets. The lower atmosphere of Venus includes significant concentrations of various gaseous sulfur compounds. The inlet leak to the mass spectrometer was temporarily blocked by an apparently liquid component of the Venus clouds during passage through the dense cloud layer. Analysis of gases released during the evaporation of the droplets shows the presence of water vapor to some compound or compounds of sulfur.

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

    PubMed

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

    2007-11-29

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

  19. Clouds and aerosols on Venus: an overview

    NASA Astrophysics Data System (ADS)

    Titov, Dmitri; Ignatiev, Nikolay; McGouldrick, Kevin; Wilquet, Valerie; Wilson, Colin

    2015-04-01

    The past decade demonstrated significant progress in understanding of the Venus cloud system. Venus Express observations revealed significant latitudinal variations and temporal changes in the global cloud top morphology. The cloud top altitude varies from ~72 km in the low and middle latitudes to ~64 km in the polar region, correlated with decrease of the aerosol scale height from 4 ± 1.6 km to 1.7 ± 2.4 km marking a vast polar depression. The UV imaging shows the middle latitudes and polar regions in unprecedented detail. The eye of the Southern polar vortex was found to be a strongly variable feature with complex morphology and dynamics. Solar and stellar occultations give access to a vertical profiling of the light absorption by the aerosols in the upper haze. The aerosol loading in the mesosphere of Venus investigated by SPICAV experiment onboard Venus Express between 2006 and 2010 was highly variable on both short and long time scales. The extinction at a given altitude can vary with a factor of 10 for occultations separated by a few Earth days. The extinction at a given altitude is also significantly lower towards the poles (by a factor 10 at least) compared to the values around the equator, while there is apparently no correlation between the extinction and the latitude in the region comprised between ±40° around the equator. Based on the Mie theory and on the observed spectral dependence of light extinction in spectra recorded simultaneously in the UV (SPICAV-UV), in the near IR (SPICAV-IR), and in the short-and mid-wavelength IR (SPICAV-SOIR), the size distribution of aerosols in the upper haze of Venus was retrieved, assuming H2SO4/water composition of the droplets. The optical model includes H2SO4 concentrations from 60% to 85%. A number of results are strikingly new: (1) an increase of the H2SO4 concentration with a decreasing altitude (from 70-75% at about 90 km to 85% at 70 km of altitude) and (2) Many SOIR/SPICAV data cannot be fitted when using

  20. Clouds and aerosols on Venus: an overview

    NASA Astrophysics Data System (ADS)

    Titov, D. V.; Ignatiev, N. I.; McGouldrick, K.; Wilquet, V.; Wilson, C. F.

    2014-04-01

    The past decade demonstrated significant progress in understanding of the Venus cloud system. This paper gives a summary of new observations and modelling efforts that will form the basis for a relevant chapter in the Venus III book. Venus Express observations reveal significant latitudinal variations and temporal changes in the global cloud top morphology [1]. The cloud top altitude varies from ~72 km in the low and middle latitudes to ~64 km in the polar region, correlated with decrease of the aerosol scale height from 4 ± 1.6 km to 1.7 ± 2.4 km marking a vast polar depression [2, 3]. UV imaging shows the middle latitudes and polar regions in unprecedented detail. The eye of the Southern polar vortex was found to be a strongly variable feature with complex morphology and dynamics [4]. Solar and stellar occultations give access to a vertical profiling of the light absorption by the aerosols in the upper haze. The aerosol loading in the mesosphere of Venus investigated by SPICAV experiment onboard Venus Express between 2006 and 2010 was highly variable on both short and long time scales. The extinction at a given altitude can vary with a factor of 10 for occultations separated by a few Earth days. The extinction at a given altitude is also significantly lower towards the poles (by a factor 10 at least) compared to the values around the equator, while there is apparently no correlation between the extinction and the latitude in the region comprised between ±40° around the equator [5]. Based on Mie theory and on the observed spectral dependence of light extinction in spectra recorded simultaneously in the UV (SPICAV-UV), in the near IR (SPICAV-IR), and in the short-and midwavelength IR (SPICAV-SOIR), the size distribution of aerosols in the upper haze of Venus was retrieved, assuming H2SO4/water composition of the droplets [6]. The optical model includes H2SO4 concentrations from 60 to 85%. A number of results are strikingly new: (1) an increase of the H2SO4

  1. Chemical reactions between Venus' surface and atmosphere - An update. (Invited)

    NASA Astrophysics Data System (ADS)

    Treiman, A. H.

    2013-12-01

    The surface of Venus, at ~740K, is hot enough to allow relatively rapid chemical reactions between it and the atmosphere, i.e. weathering. Venus chemical weathering has been explored in detail [1], to the limits of available data. New data from Venus Express (VEx) and new ideas from exoplanets have sparked a modest renewal of interest in Venus weathering. Venus' surface cannot be observed in visible light, but there are several NIR ';windows' through its atmosphere that allow surface imaging. The VIRTIS spectrometer on VEx viewed the surface through one window [2]; emissivity variations among lava flows on Imdr and Themis Regios have been explained as varying degrees of weathering, and thus age [3]. The VMC camera on VEx also provides images through a NIR window, which suggest variable degrees of weathering on some basaltic plains [4]. Indirect evidence for weathering may come from varying SO2 abundance at Venus' cloud tops; repeated rapid increases and gradual declines may represent volcanic eruptions followed by weathering to form sulfate minerals [5]. Continued geochemical modeling relevant to Venus weathering is motivated by expolanet studies [6]. Models have been extended to hypothetical exo-Venuses of different temperatures and surface compositions [7]. The idea that Venus' atmosphere composition can be buffered by reaction with its surface was explored in detail, and the derived constraint extended to other types of planets [8]. Several laboratories are investigating Venus weathering, motivated in part by the hope that they can provide real constraints on timescales of Venus volcanism [3]. Aveline et al. [9] are extending early studies [10] by reacting rocks and minerals with concentrated SO2 (to accelerate reaction rates to allow detectability of products). Kohler et al. [11] are investigating the stability of metals and chalcogenides as possible causes of the low-emissivity surfaces at high elevations. Berger and Aigouy [12] studied rock alteration on a

  2. Venus Data Analysis Program: Directory of Research Projects (1993-1994)

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This directory provides information about the scientific investigations funded by the NASA Venus Data Analysis Program (VDAP) during fiscal year 1993. The VDAP Directory consists of summary sheets from the proposals that were selected by NASA for funding in FY 93. Each summary sheet indicates the title, principal investigator, institution of the investigation, and information related to the objectives of the research activities proposed for FY 93. The objective of the VDAP Program is to advance our understanding of the nature and evolution of Venus. VDAP supports scientific investigation using data obtained from the Magellan, Pioneer Venus, and other Venus missions, as well as earth-based observations that contribute to understanding the physical and evolutionary properties of Venus. The program intends to enhance the scientific return from these missions by broadening the participation in the analysis of Venus data. Categories of research funded by VDAP are atmosphere, ionosphere, geology, geophysics, and mapping. The directory is intended to provide the science community with an overview of the research projects supported by this program. Research activities identified in this directory were selected for funding in FY 93 on the basis of scientific peer review conducted by the VDAP Review Panel.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  4. The Pioneer Venus Orbiter: 11 years of data. A laboratory for atmospheres seminar talk

    NASA Technical Reports Server (NTRS)

    Kasprzak, W. T.

    1990-01-01

    The Pioneer Venus Orbiter has been in operation since orbit insertion on December 4, 1978. For the past 11 years, it has been acquiring data in the salient features of the planet, its atmosphere, ionosphere, and interaction with the solar wind. A few of the results of this mission are summarized and their contribution to our general understanding of the planet Venus is discussed. Although Earth and Venus are often called twin planets, they are only superficially similar. Possessing no obvious evidence of plate tectonics, lacking water and an intrinsic magnetic field, and having a hot, dense carbon dioxide atmosphere with sulfuric acid clouds makes Venus a unique object of study by the Orbiter's instruments.

  5. The International VEGA "Venus-Halley" (1984-1986) Experiment: Description and Scientific Objectives

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Venus-Halley (Vega) project will provide a unique opportunity to combine a mission over Venus with a transfer flight to Halley's comet. This project is based on three research goals: (1) to study the surface of Venus; (2) to study the air circulation on Venus and its meteorological parameters; and (3) to study Halley's comet. The objective of the study of Halley's comet is to: determine the physical characteristics of its nucleus; define the structure and dynamics of the coma around the nucleus; define the gas composition near the nucleus; investigate the dust particle distribution as a function of mass at various distances from the nucleus; and investigate the solar wind interaction with the atmosphere and ionosphere of the comet.

  6. Nonthermal escape of hydrogen and deuterium from Venus and implications for loss of water

    NASA Technical Reports Server (NTRS)

    Kumar, S.; Hunten, D. M.; Pollack, J. B.

    1983-01-01

    As the dominant nonthermal mechanism for the escape of hydrogen in past Venus atmospheres, the charge exchange of H(+) with H would have provided an escape flux close to the diffusion-limiting value for H-mixing ratios up to 0.002 at the homopause, which also marks the onset of hydrodynamic flow. Charge exchange therefore represents a viable mechanism through which Venus could have lost up to an earth-equivalent ocean of water from its atmosphere over geologic time. Present Venus atmosphere estimates are based on in situ Pioneer Venus mission measurements, and assumptions in the course of extrapolation to past atmospheres have been with respect to the nature of the bulge, circulation pattern, and ion temperature.

  7. Recent hotspot volcanism on Venus from VIRTIS emissivity data.

    PubMed

    Smrekar, Suzanne E; Stofan, Ellen R; Mueller, Nils; Treiman, Allan; Elkins-Tanton, Linda; Helbert, Joern; Piccioni, Giuseppe; Drossart, Pierre

    2010-04-30

    The questions of whether Venus is geologically active and how the planet has resurfaced over the past billion years have major implications for interior dynamics and climate change. Nine "hotspots"--areas analogous to Hawaii, with volcanism, broad topographic rises, and large positive gravity anomalies suggesting mantle plumes at depth--have been identified as possibly active. This study used variations in the thermal emissivity of the surface observed by the Visible and Infrared Thermal Imaging Spectrometer on the European Space Agency's Venus Express spacecraft to identify compositional differences in lava flows at three hotspots. The anomalies are interpreted as a lack of surface weathering. We estimate the flows to be younger than 2.5 million years and probably much younger, about 250,000 years or less, indicating that Venus is actively resurfacing.

  8. Venus Night Airglow Distibutions and Variability: NCAR VTGCM Simulations

    NASA Astrophysics Data System (ADS)

    Brecht, Amanda; Bougher, S.; Gerard, J.; Rafkin, S.; Foster, B.

    2008-09-01

    The National Center for Atmospheric Research (NCAR) thermospheric general circulation model for Venus (VTGCM) is producing results that are comparative to Pioneer Venus and Venus Express