EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Venus Atmospheric Structure Investigation (VASI) on the DAVINCI Probe

Ralph Lorenz1 and the VASI Team*
Ralph Lorenz and the VASI Team
  • 1Johns Hopkins Applied Physics Lab, Laurel, USA (
  • *A full list of authors appears at the end of the abstract

The only near-surface temperature/pressure profile of the atmosphere of our twin planet, Venus, was obtained in 1985 by the VEGA-2 lander. The handful of other probe missions have very limited vertical resolution, or sensor failures in the lowest few km.  Unlike altitudes above 40km, which have been relatively well-surveyed by radio occultation profiles from orbiter missions, the fine temperature structure of lowest part of the Venus atmosphere must be interrogated by direct measurement. This structure is important in several respects. First, the structure and composition reflects the interactions between surface and atmosphere of an ‘exoplanet in our back yard’ which may be much more typical than are those of Earth. Secondly, there are indications that particularly interesting phenomena may occur on Venus, not seen in the atmospheres of Earth, Mars or Titan (but analogous to aspects of ocean stratification on Earth): the VEGA-2 profile is impossible to reconcile with a profile that is both convectively stable and compositionally uniform. A favored hypothesis is that the lowest few kilometers are compositionally denser (lower N2). The supercritical thermodynamics of carbon dioxide add to the rich possibilities in this region.

The exchange of angular momentum between the retrograde, slowly-rotating Venus and its dense atmosphere is reflected in the wind profile, which can now be interpreted by global circulation models. Again, while cloud-top (60-70km) winds are now well-known from Akatsuki and preceding missions, very little data exist on winds in the hidden lowest 40km.  Doppler tracking, turbulence measurements, and trajectory reconstruction from descent imaging will shed unprecedented light on the lower atmospheric dynamics.

DAVINCI was selected for flight in 2021 and is presently under development for launch in 2029. This presentation will review how the VASI’s measurements of pressure, temperature and wind, far superior in resolution and/or quantity to those of previous missions, may improve our understanding of Venus and complement DAVINCI’s composition measurements and imaging.

VASI Team:

Ralph Lorenz, James Garvin, Natasha Johnson, Stephanie Getty, Giada Arney, Francois Forget, Sebastien Lebonnois, Noam Izenberg, David Atkinson, David Crisp

How to cite: Lorenz, R. and the VASI Team: Venus Atmospheric Structure Investigation (VASI) on the DAVINCI Probe, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7105,, 2023.