Planetary Atmospheres and Applications

Les événements de la communauté
23 septembre 2021
de 09H00 à 16H40
  • Accessible via visioconférence
  • Public
  • Marie ANSART animateur

You will find below the program of the workshop.

Below the program, you will also find a button "S'inscrire" or "Register" that you must follow to receive the Zoom link to connect to the workshop.
The registration deadline is set to September, 21, 23:00 CEST. The link will only be sent to registered participants on September, 22.


Note: Times are French Times (CEST) = UTC + 2h

9h-9h15: Registration / Connection

9h15-9h30: Welcome

9h30-10h: David Jesch (ESA)

“Aerobraking for TGO”

The ExoMars TGO aerobraking campaign was a unique and challenging task from a Flight
Dynamics perspective. Due to the highly variable nature of the Martian atmosphere and the
limited number of previous aerobraking missions, the experience and data gathered continuously
during the daily operations were invaluable and sometimes surprising despite all the
thorough preparations. The objective of this presentation is to review and analyse all this
information in hindsight, to provide further insight about the variability and modelling of
the atmosphere, to try to explain observed phenomena that were not well-understood during
operations, and to identify the key lessons learned that could be valuable for similar future
projects. The investigation focused on three main concepts (the scale height, along-track
and orbit-to-orbit density variations) and compared various atmosphere models along these
lines. The main conclusion of the retrospective analysis is that it is possible to increase the accuracy of density
predictions compared to the operationally used approach by taking into consideration the
main sources of variability: the longitude dependent planetary-scale thermal tides.

10h00-10h10: Questions

10h10-10h25: Coffee break

10h25-11h05: Jean-Charles Marty (CNES)

”Orbit determination coupled to accelerometers measurements for Mars TGO and Venus VEX”

During the aerobraking phases of ExoMars TGO and Venus Express spacecraft we can analyze the accelerometer data which mainly measure the effect of the atmospheric drag on the satellite. If we compute a precise orbit and orientation of the satellite we can infer the total thermopheric density of the atmosphere.

11h05-11h15: Questions

11h15-11h45: Marie Ansart (TAS)

“Aerobraking around Venus”

After the Martian experience, the aerobraking challenge continues in the Venusian environment. The EnVision mission aims at studying Venus vicinity. It consists in a joint mission with NASA, intending to observe Venus at a higher resolution than previously attainable. Carrying 6 experiments (an S-band Synthetic Aperture Radar performing Interferometry SAR, a Subsurface Radar Sounder, a suite of 3 spectrometers, a Radio Science Experiment), EnVision will in particular investigate for signs of active geology and be looking for evidences of the past existence of oceans. One of the biggest technical challenges of this mission is the aerobraking phase after the interplanetary transfer, the capture by Venus and the apocenter lowering phase. A lot of operational, thermal, structural and communication constraints should be respected to achieve the final science orbit.

11h45-11h55: Questions

12h-13h30: Lunch break

13h30-14h: Fabrice Cipriani (ESA)

“ESA and CNES sponsored Climate databasesat Mars and Venus and applications”

The well established Mars Climate Database and the newly developed Venus Climate Database are essential environmental tools for mission design, operations planning, and science data analysis. The Mars Climate Database, together with complementary tools and models such as the Mesoscale model and the Mars Illumination Tool, from their initiation, continuous improvement and distribution to a constantly growing user community have been supported by CNES and ESA over many years, with successful application to existing missions to Mars, including e.g. the recent NASA MAVEN and InSight missions, ESA/ TGO, ESA/EXOMARS preparation, and at this very moment, the  Earth Return Orbiter and Sample Fetch Rover elements of the NASA/ESA Mars Sample Return mission.
With an international effort towards the exploration of Venus now ongoing, a number of missions are currently under design. ESA is now starting the phase B study for its next mission to Venus, EnVision, with a critical use of the Venus Climate Database, to better constrain the aerobraking corridor and attempt to reduce mission margins. In this rich planetary missions context we will provide an overview of the tools developments historical timeline, main specifications and goals, and describe some applications to European missions preparations and exploitation.

14h-14h10: Questions

14h10-14h40: François Forget (LMD) part 1

“Atmosphere models for Mars”

For more 25 years we have been developing global and mesoscale climate models of the Martian environment analogous to the one used for weather forecasting and climate change studies on Earth, but carefully adapted to the Martian conditions. The aim of this modeling is high: ultimately to build numerical simulators based only on universal equations, yet able to consistently reproduce available observations. The scientific applications of such models are numerous, and they remain the best tools to predict the conditions encountered by a spacecraft in orbit, during entry-descent and landing, and at the surface. For these technical applications, we have thus developed a dedicated tool, the “Mars Climate Database” (MCD) based on carefully validated climate model simulations. The MCD is available on the web ( or using a more complete, professional “full” version that has already been downloaded by more than 500 teams around the world. In particular the MCD has been officially used for all spacecraft missions launched to Mars in the past 20 years.

14h40-14h50: Questions

14h50-15h20: Sébastien Lebonnois (LMD) part 2

“Atmosphere models for Venus”

Based on similar tools as for Earth and Mars, we have developed a Global Climate Model for the atmosphere of Venus, as well as meso- and micro-scale models. They give us a better understanding of the atmospheric processes, and efficient tools to prepare and analyse observational datasets.

I will present our modeling tools developed for Venus and illustrate their performances in different atmospheric regions. Then I will present the brand new Venus Climate Database, that allows the scientific and engineering community to access the atmospheric characteristics, through our best tuned simulations.

15h20-15h30: Questions

15h30-15h45: Coffee break

15h45-16h15: Martin Rubin (Bern University)

“Outgassing model of the coma CG-67P”

ESA’s Rosetta mission followed comet 67P/Churyumov-Gerasimenko for more than 2 years and carried out an in-depth investigation of its nucleus and surrounding coma. One goal of the mission was to study the outgassing activity and coma composition as the comet covered a range in heliocentric distance from 3 au through perihelion at 1.24 au and out again. Despite continuous measurements by the different payload instruments the dataset remained sparse, limited to densities at the location of Rosetta and column densities along the viewing direction of the spacecraft. Numerical models are hence required to obtain a global scale picture of the neutral gas coma and corresponding distribution of activity on the nucleus. In this presentation we will revisit some of the different simulation approaches and results thereof.

16h15-16h25: Questions

16h25-16h40: Meeting conclusion

End around 16h45

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