EnVision

Two launch dates for EnVision are in circulation. ESA's own pages, re-read on 4 November 2026, say November 2031 (the esa.int factsheet, the mission hub and the Cosmos mission page, which adds back-up years of 2032 and 2033), and so does the French space agency CNES. ESA's UK news story of 13 May 2026 says 2031, the Cosmos timeline, last updated in December 2025, says December 2031, and ESA's abstract for the Europlanet Science Congress (EPSC), updated on 2 July 2026, says 'early 2030s'. On 10 September 2026 Ars Technica reported, in the reporter's words and without a quotation, that ESA had delayed the launch by a year to 2032 so European teams could deliver a radar, and gave 2032 again on 14 October. eeNews Europe gave the same year, and the French sites Clubic and Journal du Geek repeated it, both citing Ars. No ESA page gives 2032, so this page treats it as a reported slip to the earlier of ESA's two back-up years.

The radar is the cause. NASA agreed to supply EnVision's S-band synthetic aperture radar, VenSAR, from its Jet Propulsion Laboratory (JPL), with Deep Space Network support, in return for US places on the science team. At the September congress, ESA project scientist Anne Grete Straume-Lindner told Ars that 'it is looking like they are not able to provide the radar', while a NASA spokesperson said 'NASA conversations with ESA regarding Envision are ongoing'. At a meeting of NASA's Venus Exploration Analysis Group in early October, NASA program scientist Nick Lang confirmed that the agency was pulling out, citing its budget: 'That decision was not an easy one.' ESA's Envision news page now says NASA's contribution 'is in the process of being withdrawn', and ESA's radar page describes VeraSAR in its place. Ars reported that dropping the radar, along with cancelling Mars Sample Return, freed money for NASA's own Venus missions.

Behind those statements sits a year of US budget trouble. The White House's 2026 budget request proposed ending the contribution; on 17 July 2025 the Senate Appropriations Committee answered with a report whose bill provided 68.9 million dollars to keep VenSAR in development. On 8 January 2026 ESA's director of science, Carole Mundell, said VenSAR had recently passed its preliminary design review, and set the hard edge of the problem: EnVision must leave in 2033 at the latest, or wait at least three years for the next workable alignment of the planets. NASA's 2027 budget request, published in April 2026, does not mention EnVision or VenSAR, and The Planetary Society's analysis of 23 April 2026 reads it as eliminating the US contribution. Ars reports that a joint NASA and ESA Venus Science Coordination group has been suspended.

Europe's fallback took shape through the spring. On 26 March 2026 ESA called for scientists to join a EuroSAR Science Team and announced a competitive Phase B1, the stage that matures a design, for a European radar it described as a backup to VenSAR. Its requirements were kept identical to VenSAR's so the science and the spacecraft would not change, and ESA targeted a June 2026 kick-off. The science team, appointed in June and chaired by Alice Le Gall of LATMOS, renamed the instrument VeraSAR (Venus radiometer altimeter and SAR); it includes Richard Ghail of Royal Holloway, first author of the EnVision proposals from 2011 onward. Ars reports that industrial teams in the United Kingdom and Italy hold study contracts. ESA had not named them by early November 2026, and no primary source seen for this page confirms the date Phase B1 actually began.

A European radar is where EnVision began. The concept appeared online in August 2011 in Experimental Astronomy, answering ESA's call for a medium-size mission launching in 2022, and that early EnVision was a different machine: a five-year mission whose payload ran from a radar interferometer to a Doppler lidar and a magnetometer. A three-instrument version was passed over in ESA's fourth medium-class call (M4) on 4 June 2015, when ESA chose Ariel, Thor and Xipe for further study. A 2016 abstract by Ghail, Colin Wilson and Thomas Widemann explains the shift: the M4 version had been squeezed by the mass and volume of a Soyuz launch, while the fifth call allowed an Ariane 6.2, so cost became the limit. The radar then derived from the United Kingdom's low-cost NovaSAR-S, with pass-to-pass interferometry to measure centimetre-scale ground movement. The M5 proposal went in during October 2016, aiming at a 2029 launch.

EnVision went through a Phase 0 study with Theseus and SPICA in 2018, and Phase A began in 2019. That is when NASA's contribution was set, moving the radar from a British design to a JPL one that kept the name VenSAR; Space.com reported in January 2026 that it had originally been meant to be built by Airbus in the United Kingdom. The modes ESA lists today, stereo topography among them, do not include interferometry, and the Cosmos page notes that radar stereo, unlike interferometry, does not use the phase of the signal.

ESA's Assessment Study Report, the 'Yellow Book' of February 2021, fixed the design put to the vote: an Ariane 62 launch in a window opening on 29 May 2032 and a dry mass of 1.35 tonnes. On 10 June 2021 ESA's Science Programme Committee chose EnVision over Theseus as the fifth medium-class mission of Cosmic Vision, and ESA gave 2031 as the earliest launch, with options in 2032 and 2033. Adoption on 25 January 2024 moved EnVision into implementation, with an Ariane 6 launch in 2031, and ESA and NASA signed their memorandum of understanding in the first quarter of 2024.

The spacecraft grew on the way. ESA now describes a box of about 2 by 2 by 3 m when stowed, weighing about 4.1 tonnes fuelled and 1.7 tonnes dry, to launch on an Ariane 64 from Kourou. Some pages lag. CNES's page, last modified on 6 October 2025, still names an Ariane 62, a dry mass of 1.6 tonnes, a stowed size of 2 by 2 by 2 m and an end of mission in January 2039.

Industry came on board in two steps. ESA's Cosmos timeline dates the choice of Thales Alenia Space as prime contractor to December 2024, and the contract, worth 367 million euros according to the company's Italian release, was signed on 28 January 2025 in Brussels. That release expected a system preliminary design review in May 2026 and full authorisation for construction (phases C and D) in June 2026; ESA's timeline instead lists the spacecraft preliminary design review for the third quarter of 2026. No ESA or company statement found by early November 2026 confirms either milestone. In May 2026 OHB Space UK signed a preliminary authorisation to proceed with Thales Alenia Space for the assembly, integration and testing of the spacecraft, a role European Spaceflight values at about 24 million euros.

At Venus, reaching the science orbit is a long job in itself. The spacecraft first brakes into a very high, elongated orbit; ESA's study manager Thomas Voirin said in 2022 that insertion would be at roughly 250,000 km, after which repeated dips into the upper atmosphere, as low as 130 km, would bring the orbit down to about 500 km. In his words, 'Envision as currently conceived cannot take place without this lengthy phase of aerobraking.' The duration differs by source: about 16 months in 2021, 11 months on today's ESA pages, 18 on the CNES page, about a year for Thales Alenia Space and 'up to two years' in ESA's 2022 technology story.

Its final orbit is near-polar, inclined 87° to 89°, at about 220 to 510 km, with a period of about 92 minutes on the Cosmos mission page and 94 on the factsheet; older ESA and industry documents give an upper altitude of 540 km. Because Venus turns so slowly, coverage builds up over the nominal science phase of six Venus sidereal days, about four Earth years, which ESA's Cosmos pages start in mid-2034.

Two radars share the job of seeing through the clouds. VeraSAR keeps the requirements set for VenSAR: regions of up to 1,000 by 1,000 km imaged at 30 m and targets of up to 100 by 100 km at 10 m, in HH and HV polarisations, plus stereo, radiometry and altimetry. ESA says the radar will distinguish features more than ten times smaller than Magellan could, and comparisons with Magellan's images and with its own repeat passes are meant to reveal volcanic, tectonic and landscape-forming change. The second radar, VESPER (formerly the Subsurface Radar Sounder), is procured by the Italian space agency ASI with Lorenzo Bruzzone as lead scientist. It looks straight down at 9 MHz through a deployable dipole antenna 16 m across.

How deep VESPER will see depends on who is describing it, and on the rock. The Cosmos instrument page, working from Venus-like basalts measured in the laboratory, gives an average penetration of about 600 m. The ESA factsheet says 'down to one kilometre' and the Yellow Book 'the top kilometre', while ASI and the University of Trento wrote in 2021 of a few hundred metres. The sounder will survey about a fifth of the planet densely and more than 80 percent sparsely, looking for buried craters, stacked lava flows and the inner structure of the ridged terrain called tesserae.

Three spectrometers make up the VenSpec suite, led by DLR, the German aerospace centre. VenSpec-M maps the night-side glow of the hot surface through near-infrared windows in the clouds, a method ESA says VIRTIS pioneered on Venus Express. VenSpec-H, from BIRA-IASB in Belgium, measures water vapour and its heavy form HDO near the ground and, at 30 to 40 km, those two with carbonyl sulfide and sulfur dioxide. VenSpec-U, from LATMOS with CNES building it, maps sulfur dioxide, sulfur monoxide and the still unidentified ultraviolet absorber at the cloud tops. DLR sketches how they would work together: VenSpec-M would see the heat of fresh lava, VenSpec-H the water vapour an eruption released and VenSpec-U its sulfur dioxide high above.

Radio science, the sixth investigation, needs no instrument box of its own. VeRSE (formerly RSE), led by Caroline Dumoulin of LPG Nantes with CNES leading procurement, uses the spacecraft's X- and Ka-band links. Tracking should yield a gravity field resolved to about 150 to 200 km everywhere, improving on Pioneer Venus and Magellan, and measure the tidal Love number k2, which constrains the size and state of the core in the absence of seismometers. As the spacecraft passes behind the planet, the fading signal will sound the atmosphere from about 90 km down to 35 km, and ESA's page says the Ka-band link will measure gaseous and liquid sulfuric acid at about 45 to 55 km for the first time.

ESA frames all this with a short list of questions: how the surface and interior evolved, how active Venus is today, how geology shapes the atmosphere and climate, and whether evidence of past water survives in the oldest rocks. The case rests partly on hints of possible volcanic hotspots from Venus Express, and ESA presented it as working alongside NASA's VERITAS and DAVINCI; the science itself is covered in Volcanoes on Venus and Oceans and the greenhouse. On 17 June 2024 ESA named Yeon Joo Lee of Korea's Institute for Basic Science a VenSpec co-investigator, which Yonhap reported gives unrestricted access to VenSpec data at no cost to Korea.

What remains open in November 2026 is mostly the calendar. ESA's own pages have not said whether its long-listed 2032 back-up is now the plan, and ESA has not named the industrial team that will build VeraSAR. For a launch at the end of 2031, ESA's timeline puts arrival in the second quarter of 2033 and the start of science in mid-2034; it has published no equivalent dates for a 2032 departure. The fixed point is the 2033 limit Mundell gave in January.