EnVision will be ESA’s next Venus orbiter, providing a holistic view of the planet from its inner core to the upper atmosphere to determine how and why Venus and Earth evolved so differently.
The mission was selected by ESA’s Science Program Committee on June 10 as the fifth middle-class mission of the Agency’s Cosmic Vision plan, aimed at launch in the early 2030s.
“A new era in the exploration of our nearest neighbor, but very different from the solar system, awaits us,” said Günther Hasinger, ESA Scientific Director. “With the Venus missions recently announced by NASA, we will have an extremely comprehensive science program on this enigmatic planet over the next decade.”
A key question in planetary science is why, despite being roughly the same size and makeup, our next door neighbor in the inner solar system has experienced such dramatic climate change: instead of Being a habitable world like Earth, it has a toxic atmosphere and is surrounded by thick clouds rich in sulfuric acid. What history did Venus go through to get to this state and does this predict the fate of the Earth if it too experiences a catastrophic greenhouse effect? Is Venus still geologically active? Would he have already welcomed an ocean and even supported life? What lessons can we learn from the evolution of terrestrial planets in general, as we discover more and more Earth-like exoplanets?
EnVision’s innovative toolkit will tackle these big questions. It will be equipped with a suite of European instruments including a sounder to reveal underground layers, and spectrometers to study the atmosphere and the surface. The spectrometers will monitor traces of gas in the atmosphere and analyze the composition of the surface, looking for any changes that may be related to signs of active volcanism. A radar provided by NASA will image and map the surface. In addition, a radio science experiment will probe the internal structure and gravity field of the planet and study the structure and composition of the atmosphere. The instruments will work together to better characterize the interplay between the different borders of the planet – from the interior to the surface to the atmosphere – providing a holistic global view of the planet and its processes.
EnVision follows ESA’s hugely successful Venus Express (2005-2014), which primarily focused on atmospheric research, but also made spectacular discoveries indicating possible volcanic hotspots on the planet’s surface. . JAXA’s Akatsuki spacecraft has also been studying the atmosphere since 2015. EnVision will significantly improve the surface radar images obtained by NASA’s Magellan in the 1990s. In collaboration with upcoming NASA missions DAVINCI + (Deep Atmosphere Venus Investigation of Noble gas, Chemistry, and Imaging) and VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy), the trio of new spacecraft will provide the most comprehensive study of Venus ever.
“EnVision benefits from a collaboration with NASA, combining the excellence of European and American expertise in Venus science and technology, to create this ambitious mission,” said Günther. “EnVision further strengthens Europe’s role in the scientific exploration of the solar system. Our growing fleet of missions will give us and future generations the best insight into how our planetary neighborhood works, particularly relevant at a time when we are increasingly discovering unique exoplanet systems. “
“We are delighted to contribute to ESA’s exciting new mission to investigate Venus,” said Thomas Zurbuchen, Associate Administrator for Science at NASA. “EnVision leverages the strengths of our two agencies in instrument development. Combined with NASA’s Discovery missions to Venus, the scientific community will have a powerful and synergistic set of new data to understand how Venus formed and how the surface and atmosphere have changed over time.
Following an initial call for the Fifth Middle Class Mission Concept in 2016, final competition went to EnVision and Theseus, the Transient High-Energy Sky and Early Universe Surveyor. Theseus would monitor transient events across the sky and specifically focus on gamma-ray bursts in the Universe’s first billion years, to help shed light on the life cycle of the first stars. Although Envision was recommended by the main scientific committee, it was recognized that Theseus also has a very compelling scientific record that could make extremely important contributions in the field.
The next step for EnVision is to move on to the detailed “definition phase”, during which the satellite and instrument design is finalized. After the design phase, a European industrial contractor will be selected to build and test EnVision prior to launch on an Ariane 6 rocket. The first launch opportunity for EnVision is 2031, with further options possible in 2032 and 2033. The spacecraft would take about 15 months to reach the planet, with another 16 months to achieve circularization of the orbit thanks to the airbrake. Its 92-minute orbit will be quasi-polar with an altitude between 220 km and 540 km.
Solar Orbiter, Euclid, Plato and Ariel have already been selected as middle class missions. Solar Orbiter was launched in February 2020; Euclid, Plato and Ariel will be launched throughout this decade.
EnVision is an ESA-led mission with significant contributions from NASA, which will provide VenSAR (Synthetic Aperture Radar), as well as support for the Deep Space Network. The other payload instruments are supplied by ESA Member States, ASI, DLR, BelSPO and CNES leading respectively the supply of SRS (Subsurface Sounding Radar), VenSpec-M, VenSpec-H and VenSpec-U. The scientific radio experiment is carried out by institutes in France and Germany.