Science objective and status of the EnVision Mission to Venus

EnVision is the fifth Medium-class mission in ESA’s Science Program, selected in June 2021 and adopted in January 2024. EnVision is an ESA-led mission in partnership with NASA, where NASA provides the Synthetic Aperture Radar payload and mission support. The mission launch is scheduled for 2031; science operations at Venus will start early 2035 following the mission cruise and aerobraking phase to achieve a low polar orbit. The scientific objective of EnVision is to provide a holistic view of the planet from its inner core to its upper atmosphere, studying the planet's long-term history, activity and climate. EnVision aims to establish the nature and current state of Venus’ geological evolution and its relationship with the atmosphere. EnVision’s science objectives are to: (i) characterize the sequence of events that formed Venus' surface, and the geodynamic framework that has controlled Venus' internal heat release ; (ii) determine how geologically active the planet is today; (iii) establish the interactions between the planet and its atmosphere at present and through time. Furthermore, EnVision will look for evidence of past liquid water on its surface.
The nominal science phase of the mission will last six Venus sidereal days (~four Earth years), and ~210 Tbits of science data will be downlinked using a Ka-/X-band communication system. The science objectives will be addressed by five instruments and one experiment, provided by ESA member states and NASA. The VenSAR S-band radar will perform targeted surface imaging, polarimetric and stereo imaging, radiometry, and altimetry. The high-frequency Subsurface Radar Sounder (SRS) will sound the upper crust in search of material boundaries. Three spectrometers, VenSpec-U, VenSpec-H, and VenSpec-M, operating in the UV and Near- and Short Wave-IR, will map trace gases, search for volcanic gas plumes above and below the clouds, and map surface emissivity and composition. A Radio Science Experiment (RSE) investigation will exploit the spacecraft Telemetry Tracking and Command (TT&C in Ka-/X bands) system to determine the planet’s gravity field and to sound the structure and composition of the middle atmosphere and cloud layer in radio occultation. All instruments have substantial heritage and robust margins relative to the requirements, with designs suitable for operation in the Venus environment. The EnVision science teams will adopt an open data policy, with public data release of the scientific data after validation and verification. Public calibrated data availability is <6 months after data downlink.

The EnVision Science Study Team*, the EnVision Study Team at ESA, the instrument teams and industry are thanked for their contributions.

*The EnVision Science Working Team: Giulia Alemanno (DLR, Berlin, DE), Lorenzo Bruzzone (RSL, Università di Trento, IT), Caroline Dumoulin (LPG, Nantes Université, FR), Martin Ferus (JHI-CAS, CZ), Scott Hensley (Jet Propulsion Laboratory, Pasadena, CA, USA), Luisa Lara (IAA, SP), Jérémie Lasue (IRAP, Université Toulouse-III-Paul-Sabatier, FR), Emmanuel Marcq (LATMOS, IPSL, Guyancourt, FR), Paul Tackley (ETHZ, Switzerland), Silvia Tellmann (University of Cologne, DE), Séverine Robert (Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, BE), Sandrine Vinatier (1), Thomas Widemann (1,2)