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DAVINCI: Deep atmosphere Venus investigation of noble gases, chemistry, and imaging.



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IMAGING. L. S. Glaze1, J. B. Garvin1, N. M. Johnson1, D. Atkinson2,3, S. Atreya4, J. Blacksberg2, W. Brincker-
hoff1, B. Campbell5, D. Crisp2, F. Forget6, M. Gilmore7, D. Grinspoon8, N. Izenberg9, P. R. Mahaffy1, W. Kiefer10,
R. Lorenz9, A. A. Pavlov1, M. Ravine11, M. G. Trainer1, C. Webster2, K. Zahnle12, and M. Zolotov13, 1NASA God-
dard Space Flight Center (Code 690, Greenbelt, MD, 20771,, 2Jet Propulsion Laboratory,
3University of Idaho, 4University of Michigan, 5Smithsonian Institution, 6Laboratoire de Météorologie Dynamique,
7Wesleyan University, 8Planetary Science Institute, 9Applied Physics Laboratory, 10Lunar and Planetary Institute,
11Malin Space Science Systems, 12NASA Ames Research Center, 13Arizona State University.
Introduction: Venus formed in the same part of
our solar system, apparently from similar materials, as
Earth. Although both planets are about the same size,
their differences are profound. Venus and Earth expe-
rienced vastly different evolutionary pathways result-
ing in unexplained differences in atmospheric compo-
sition and dynamics, as well as in geophysical process-
es of the planetary surfaces and interiors. Understand-
ing when and why the evolutionary pathways of Venus
and Earth diverged is key to understanding how terres-
trial planets form and how their atmospheres and sur-
faces evolve. The proposed Deep Atmosphere Venus
Investigation of Noble gases, Chemistry, and Imaging
(DAVINCI) mission will provide these missing puzzle
pieces needed to understand terrestrial planet for-
mation and evolution in the solar system and beyond.
Mission Concept: DAVINCI is one of five Dis-
covery-class missions selected by NASA for Phase A
studies. Launching in November 2021 and arriving at
Venus in June of 2023, DAVINCI would be the first
U.S. entry probe to target Venus’ atmosphere in 45
years. DAVINCI is designed to study the chemical and
isotopic composition of Venus’ atmosphere at a level
of detail that has not been possible on earlier missions
and to image the surface at optical wavelengths and
process-relevant scales. The three major DAVINCI
science objectives are:
Atmospheric origin and evolution: Understand the
origin of the Venus atmosphere, how it has
evolved, and how and why it is different from the
atmospheres of Earth and Mars.
Atmospheric composition and surface interaction:
Understand the history of water on Venus and the
chemical processes at work in the lower atmos-
Surface properties: Provide insights into tectonic,
volcanic, and weathering history of a typical tes-
sera terrain.
The DAVINCI probe will make in situ measure-
ments during a one-hour descent through the Venus
atmosphere. The mission is tightly focused on answer-
ing fundamental questions that have been ranked as
high priority by the last two National Research Council
(NRC) Planetary Decadal Surveys [1-3] as well as by
the Venus Exploration Analysis Group (VEXAG)
since the time of its inception in 2005 [4]. For exam-
ple, DAVINCI will make measurements of the heavi-
est noble gases, including dramatic improvements in
quantifying krypton abundance and the first ever
measurements of xenon, as well as precise isotopic
measurements. These definitive measurements, which
will be made well below the homopause to avoid any
uncertainties, are sufficient to answer questions as
framed by the NRC Planetary Decadal Survey and
VEXAG, without the need to repeat them in New
Frontiers or other future missions. The relative abun-
dances of these inert gases, together with high preci-
sion measurements of the isotopes of argon, nitrogen,
sulfur and carbon provide critical insight into the
origin of Venus’ atmosphere as well as clues regarding
the role of large impacts in its atmospheric evolution.
1560.pdf47th Lunar and Planetary Science Conference (2016)
DAVINCI will make definitive measurements of
hydrogen isotopes that can be used to constrain when
and at what rates Venus lost its putative early water
oceans. DAVINCI will also make the first-ever in situ
trace gas composition measurements within 12 km of
the surface (the altitude at which commercial airlines
cruise on Earth) where 2/3 of the Venus atmospheric
mass resides. These observations will be very useful to
future orbiting missions that need to characterize the
deep atmosphere in order to quantitatively interpret
infrared emissivity observations. The measured com-
position of chemically active gases will provide infor-
mation about chemical processes in the sub-cloud at-
mosphere, the oxidation state of the atmosphere, and
the degree of equilibration among gases in the vicinity
of the surface. This never before obtained information
regarding the composition of the near-surface Venus
atmosphere will lead to new evaluations of stability of
minerals and improved understanding of pathways for
chemical weathering of the surface.
Finally, DAVINCI will return the first-ever high
spatial resolution optical images of the enigmatic high-
land regions known as tessera terrain that may be anal-
ogous to remnant continents. Existing Magellan radar
and topography, combined with Venus Express emis-
sivity results are more than adequate for identifying an
appropriate DAVINCI descent location. The carrier
spacecraft easily receives all data during descent and
relays those data back to Earth without requiring the
presence of additional Venus-orbiting spacecraft.
Payload: DAVINCI builds on the tremendous
success of the Mars Science Laboratory Sample Anal-
ysis at Mars (MSL/SAM) suite carried on the Curiosity
rover [5-12], by pairing the Venus Mass Spectrometer
(VMS) led by NASA’s Goddard Space Flight Center
with the Venus Tunable Laser Spectrometer (VTLS)
led by the Jet Propulsion Laboratory. Combined, these
two instruments provide the first comprehensive meas-
urements of noble and trace gas species, as well as key
elemental isotopes.
These two state-of-the art instruments are comple-
mented by the Venus Atmospheric Structure Investiga-
tion (VASI), which provides measurements of the
structure and dynamics of the Venus atmosphere dur-
ing entry and descent as context for the chemistry
measurements, and enables reconstruction of the de-
scent profile.
High-contrast descent imaging of the tessera terrain
is enabled by the Venus Descent Imager (VenDI), pro-
vided by Malin Space Science Systems based on a
design that leverages experience with the Curiosity
Rover’s Mastcam and MARDI descent video imaging
References: [1] Crisp, D., et al. (2002) ASP con-
ference Series, 272, Ed. MV Sykes, 5-34. [2] New
Frontiers in the Solar System (2003) National Research
Council of the National Academies, National Acade-
mies Press. [3] Visions and Voyages (2011) National
Research Council of the National Academies, National
Academies Press. [4] VEXAG (2014)
140625.pdf. [5] Mahaffy et al. (2015) Science, 347,
412-414. [6] Webster et al. (2015) Science, 347, 415-
417. [7] Atreya et al. (2013) GRL, 40, 5605-5609. [8]
Mahaffy et al. (2013) Science, 341, 263-266. [9] Web-
ster et al. (2013) Science, 341, 260-263. [10] Wong et
al. (2013) GRL, 40, 6033-6037. [11] Conrad et al.
(2014) LPSC XLV, Abstract #2366. [12] Trainer et al.
(2016) LPSC XLVII Abstract.
1560.pdf47th Lunar and Planetary Science Conference (2016)
... Pioneer Venus probes, Venera landers and VeGa 1 and 2 missions have surveyed the composition of atmosphere till the surface. However, the measurements in the deep atmosphere of Venus i.e. below 12.5 km [1,3] and the supercritical state below 3 km do not have reliable and reproducible temperature and chemical composition data. ...
... The mission will attempt in retrieving important data related to physical state and chemistry of the Venus atmosphere in order to aid the next generation of Venus EDL missions [1,2,4] and atmospheric models to trace evolution of Venus and its distinct features w.r.t. evolution of other terrestrial planets like Earth and Mars ( Figure 2). ...
... Chemical evidences can be studied in tandem with VenDI based imaging of surface features. Comparative studies of isotopic abundances will identify sources of different isotopes and divergent evolution of terrestrial planets[1,4].VTLS will provide abundances of trace compounds like H O, SO , OCS, CO and H S with respective isotopes i.e. D, H, O, O, C, C, S, S, S. ...
The atmosphere of Venus has been explored by many probes and lander missions, which investigated different regions of the atmosphere, including chemical composition, dynamics and thermal structure. However, the repeatability and accuracy of measurements of the near-surface environments provided by the missions of previous decades is lacking, and there is a need for more accurate and precise measurements to study the near surface environment and its physical state. Vega 2 measurements are regarded as the most reliable temperature measurements for the deep atmosphere with an error bar of 0.5 K. Recent analyses of Vega 2 measurements indicate presence of a supercritical fluid state in the last few kilometers above the Venus surface, an increasing concentration of nitrogen with altitude. The DAVINCI+ deep atmosphere chemistry probe, now in Phase A led by Principal Investigator Dr. James B. Garvin and NASA GSFC will study the atmospheric structure and chemical composition of Venus’ lower atmosphere. The Venus Atmospheric Structure Investigation (VASI) payload will provide temperature and pressure measurements during the entry and descent stages, while the Venus Mass Spectrometer (VMS) payload will provide measurements for nitrogen isotope abundances. We will present a framework for the deep atmosphere chemistry probe measurements to study the physical state and thermodynamic properties of the deep atmosphere of Venus based on the knowledge and principles of thermodynamic properties of states and previous atmosphere probes. The goal of the framework is to investigate the supercritical state of Venus atmosphere, check the possibility of existence of a concentration gradient, and to take advantage of proposed DAVINCI+ probe synergistic measurements.
... (Stern, 2018 (Balaram, et al., 2021), may pave the way for flying cameras at a number of solar system bodies (see Dragonfly, for example (Lorenz, et al., 2021)). Mission designs such as the L-DART penetrator (Barber, et al., 2018) and the DAVINCI+ Venus probe (Garvin, et al., 2020) are examples of small planetary probes that can facilitate planetary imaging in a variety of scenarios. And the tried and tested orbiter and flyby spacecraft designs that have captured thousands of images over the last six decades will continue to be represented in future missions, transporting cameras throughout the solar system (e.g. ...
... Finally, the camera's multi-altitude image sequence, which permits the surface to be imaged with a range of resolutions and perspectives, and facilitates stereophotogrammetry, could be achieved with a variety of craft (e.g. such as the Mars 2020 Ingenuity helicopter (Balaram, et al., 2021) and the DAVINCI+ Venus probe (Garvin, et al., 2020)). ...
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In this thesis, a novel approach to spaceborne imaging is investigated, building upon the scan imaging technique in which camera motion is used to construct an image. This thesis investigates its use with wide-angle (≥90° field of view) optics mounted on spin stabilised probes for large-coverage imaging of planetary environments, and focusses on two instruments. Firstly, a descent camera concept for a planetary penetrator. The imaging geometry of the instrument is analysed. Image resolution is highest at the penetrator’s nadir and lowest at the horizon, whilst any point on the surface is imaged with highest possible resolution when the camera’s altitude is equal to that point’s radius from nadir. Image simulation is used to demonstrate the camera’s images and investigate analysis techniques. A study of stereophotogrammetric measurement of surface topography using pairs of descent images is conducted. Measurement accuracies and optimum stereo geometries are presented. Secondly, the thesis investigates the EnVisS (Entire Visible Sky) instrument, under development for the Comet Interceptor mission. The camera’s imaging geometry, coverage and exposure times are calculated, and used to model the expected signal and noise in EnVisS observations. It is found that the camera’s images will suffer from low signal, and four methods for mitigating this – binning, coaddition, time-delay integration and repeat sampling – are investigated and described. Use of these methods will be essential if images of sufficient signal are to be acquired, particularly for conducting polarimetry, the performance of which is modelled using Monte Carlo simulation. Methods of simulating planetary cameras’ images are developed to facilitate the study of both cameras. These methods enable the accurate simulation of planetary surfaces and cometary atmospheres, are based on Python libraries commonly used in planetary science, and are intended to be readily modified and expanded for facilitating the study of a variety of planetary cameras.
... The combination of IR spectroscopy in transparency windows, radar mapping and gravity field measurements is planned to improve the knowledge about the Venus inner structure and ongoing geological activity. DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) is a proposed atmospheric probe to Venus (Glaze et al., 2016). Venus In Situ Explorer (VISE) and The Surface and Atmosphere Geochemical Explorer (SAGE) concepts propose to land close to a volcano (Squyres, 2011;Esposito, 2011). ...
Chemical processes of the dense CO2-atmosphere of Venus are determined by trace gases such as SO2, O3, H2O, CO, etc. Among these atmospheric components, a group of sulfur and oxygen compounds occupies a central position. The objective of this thesis is a study of sulfur dioxide and ozone at the night side of Venus' upper mesosphere that is related to altitudes from 85 to 110 km. Chemistry and dynamics of this altitude range is very active. The sulfuric chemical cycle in the mesosphere leads to a formation of the thick cloud deck at 47-70 km globally enshrouding the planet. Furthermore, it has not yet been determined exactly which chemical interactions are responsible for stabilizing the equilibrium in the chemical cycles of the atmosphere, and maintaining a high mixing ratio of CO2. The difficulty of evaluating the oxidizing capacity of the atmosphere, due to the lack of direct measurements of the amount of molecular oxygen, is one reason for this. However, indirect O2 estimations can be made based on derivatives of this molecule, and one of them is ozone. This gas is involved in reactions with species, probably mainly chlorinated compounds, leading to the general chemical cycles.The research is based on the data obtained from the first stellar occultation experiment released for Venus. It was performed by the UV channel of the SPICAV spectrometer onboard Venus Express orbiter working in 2006-2014. This is a powerful instrument to measure absorption of CO2, SO2 and O3 at the night side of Venus’ atmosphere above the cloud layer. This study also includes a detailed assessment of the accuracy of the spectral data processing methods used to retrieve vertical atmospheric gas concentration distributions. Mainly it concerns a separation of a stellar light from UV emission signal originated from different spread sources, which is a parasitic light for the stellar occultation data investigation. A significant influence of a calibration assignment of wavelength to a digital pixel number was obtained. The required accuracy was achieved by a determination of stellar lines position for a large set of stars' spectra measuring in each observational session. Thus, it allowed to establish a profile of the SO2 content from 85 km to 100 km mainly devoted to mid-latitudinal range. On average, it shows a stable mixing ratio with altitude. For this gas, a prevailed short-period variability has been confirmed. However, a weak possible increase of SO2 abundance with local time is noticed from the morning to the evening terminator at 90-95 km. After the discovery of the ozone layer on Venus made by Montmessin et al. (2011), the ozone content was confirmed in more than 100 occultation sessions. The current study also shows that the detected ozone values correspond to its maximum values rather than to the thick stable layer. These results are the first detailed vertical distribution of the SO2 and O3 content in the upper mesosphere on the night side, which opens up new possibilities for the theoretical description of processes occurring in the atmosphere of Venus.
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