Envision factsheet
Overview of the Envision mission
Name: Envision
Mission: Understanding why Earth’s closest neighbour, Venus, is so different
Partnership: Envision is an ESA-led mission in partnership with NASA, with NASA providing the Synthetic Aperture Radar (VenSAR) and Deep Space Network support for critical mission phases (see below for more information on European contributions to Envision)
Why Venus?: Venus is the most Earth-like of the Sun’s terrestrial planets in terms of its size, composition and distance from the Sun. Yet at some point in planetary history, the two started to evolve very differently. Venus today is far too hot to host liquid water at its surface, but it may have had a more Earth-like climate for billions of years before developing a runaway greenhouse effect. Hence, Venus provides a natural laboratory for studying how habitability – or the lack of it – evolved in the Solar System.
Objectives: Envision will be the first mission to investigate Venus from its inner core to its upper atmosphere, characterising the interaction between its different envelopes: its atmosphere, surface/subsurface and interior. It aims to provide a holistic view of Venus, studying the planet’s history, activity and climate
The Envision mission will address a number of key questions about our neighbour:
- How have the surface and interior of Venus evolved?
- How geologically and tectonically active is Venus today, and how active has it been over the past billion years?
- How are Venus’ atmosphere and climate shaped by geological processes?
- Did Venus have oceans – and could evidence of past water remain in the oldest rocks found on Venus’ surface?
- How does Venus lose heat, and when and why did the runaway greenhouse effect begin at the planet?
Forebears/legacy: The mission builds on the success of missions including ESA’s Venus Express (2005-2014); the Soviet Venera Programme (1961-1984); NASA’s Pioneer Venus mission (1978-1992); and NASA’s Magellan Orbiter (1989-1994). For summaries of these missions and their scientific achievements, see ‘Past missions to Venus’. It will also utilise findings from JAXA’s Akatsuki mission, which entered orbit around Venus in 2015. Envision will work in synergy with NASA’s forthcoming VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) and DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) missions to provide the most comprehensive study of Venus ever
Dimensions: Envision will be a roughly rectangular three-axis stabilised satellite weighing 2.5 tonnes at launch, measuring approx. 2 m x 2 m x 3 m in stowed configuration, with two deployable solar arrays
Instruments: Envision’s science payload consists of VenSAR, a dual polarisation S-band radar also operating as microwave radiometer and altimeter, which will map the surface of Venus; three optical spectrometers (VenSpec-M, VenSpec-U and VenSpec-H) designed to observe the surface and atmosphere of Venus; and the Subsurface Radar Sounder (SRS), a High Frequency (HF) sounding radar to probe the top kilometre of subsurface. These are complemented by a Radio Science investigation exploiting the spacecraft Telemetry Tracking and Command (TT&C) system to map the planet’s gravity field and constrain its internal structure, and to measure the composition and structure of Venus’ atmosphere
Selection: The mission was selected by ESA’s Science Programme Committee on 10 June 2021 as the fifth Medium-class mission in the Agency’s Cosmic Vision plan. It was adopted on 25 January 2024.
Launch: Envision is targeting a launch in the early 2030s. The mission is foreseen to launch from ESA’s Spaceport in Kourou, French Guiana on an Ariane 62
Journey and orbit: Envision will reach Venus after a 15-month cruise. After arriving, the spacecraft will spend 15 months aerobraking through Venus’ atmosphere to progressively reach its science orbit, a low Venus quasi-polar orbit, at a variable altitude of between 220 and 540 km and with an orbital period of about 94 minutes.
Lifetime: Total nominal science period of six Venus sidereal days (four Earth years)
Contributions by ESA member states: ASI, DLR, BelSPO and CNES will respectively lead the procurement of the SRS, VenSpec-M, VenSpec-H and VenSpec-U instruments. The radio science experiment is led by institutes in France and Germany. Launch and operations will be supported by ESA’s Mission Operations Centre (MOC) at ESOC (Darmstadt) and Science Operations Centre (SOC) at ESAC (Madrid), with Instrument Operations and operational interfaces distributed across Instrument Teams.
Envision mission facts
Envision will combine observations at ultraviolet, infrared, microwave and high frequency radio wavelengths to study geological and atmospheric processes at a range of scales, from the core to the upper atmosphere of Venus.
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The spacecraft will follow up on unanswered questions raised by earlier missions to the planet including ESA’s Venus Express, which focused on atmospheric research but revealed an enigmatic planetary surface with signs of geological activity. Additional questions remain over Venus’ climate and history of water.
Recent research strongly suggests that the evolution of the atmosphere and interior of Venus are coupled, emphasising the need to study the atmosphere, surface, and interior of Venus as a system.
NASA’s contribution to Envision, VenSAR, builds on decades of planetary radar experience dating back to the NASA/JPL Magellan radar mapping mission launched to Venus in 1989.
Envision is the first mission to Venus with a subsurface radar sounding instrument (SRS), which will directly measure the planet’s subsurface features.
Furthermore, its VenSAR radar will be the first instrument to image parts of the planet at a very fine resolution of 10 metres and to perform polarimetric imaging, to further advance our knowledge of Venus’ surface.
