EnVision will be ESA’s (European Space Agency) next Venus orbiter, aimed at 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 within the agency’s Cosmic Vision plan, scheduled to launch in the early 2030s.
“A new era awaits us in exploring our closest solar system neighbor, and yet so different,” says Günther Hasinger, ESA’s Director of Science. “Along with the recently announced NASA-led missions to Venus, we will have an extremely comprehensive science program on this enigmatic planet well into the next decade.”
A key question in planetary science is why, despite being roughly the same size and composition, our inner solar system neighbor experienced such drastic climate change and instead of being a habitable world like Earth, it has an atmosphere toxic and is shrouded in dense clouds rich in sulfuric acid. What history has Venus gone through to reach this state and what fate would the Earth have if it suffered a catastrophic greenhouse effect? Is Venus Still a Geologically Active Planet? Could it ever have supported an ocean and even supported life? What lessons can we learn about the evolution of terrestrial planets in general, as we discover more Earth-like exoplanets?
EnVision’s innovative suite of instruments will address these big questions. To this end, it will be equipped with a set of European instruments including a probe to reveal the underground layers and with spectrometers to study the atmosphere and surface. The spectrometers will be in charge of controlling the traces of gases in the atmosphere and will 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 the surface and map it. In addition, a radio-scientific experiment will be carried out to probe the internal structure of the planet and its gravitational field, in addition to investigating the structure and composition of the atmosphere. The instruments will work together to characterize in the best possible way the interaction between the different limits of the planet, from the interior to the surface and the atmosphere, providing a global vision of it and its processes.
An artist’s recreation of ESA’s EnVision mission to Venus. (Image: © ESA / VR2Planets / Damia Bouic)
EnVision is the continuation of ESA’s successful Venus Express mission (2005-2014), which focused primarily on atmospheric research, but also made spectacular discoveries that pointed to possible volcanic hotspots on the planet’s surface. Same as JAXA’s Akatsuki spacecraft, which has been studying the atmosphere since 2015. EnVision will significantly enhance radar images of the surface obtained by NASA’s Magellan probe in the 1990s. Working in conjunction with upcoming DAVINCI + missions (acronym for Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) and VERITAS (acronym for Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) from NASA, the trio of new spacecraft will provide the most comprehensive study of Venus never performed before.
“EnVision benefits from the collaboration with NASA, combining the excellence of European and American knowledge in science and technology about Venus, to create this ambitious mission,” says Günther.
“EnVision further strengthens Europa’s role in the scientific exploration of the solar system. Our growing fleet of missions will provide us, and future generations, with the best insights into how our planetary neighborhood works, which is especially important at a time when we are discovering more and more unique exoplanet systems. “
“We are delighted to contribute to ESA’s exciting new mission to investigate Venus,” says Thomas Zurbuchen, NASA Associate Administrator for Science.
He adds: “EnVision takes advantage of the instrument development strengths of our two agencies; thus, 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 changed over time. “
Following the initial call for the fifth middle-class mission concept in 2016, the final competition came down to EnVision and Theseus, (an acronym for Transient High-Energy Sky and Early Universe Surveyor). Theseus will be tasked with monitoring transient events across the sky and, in particular, will focus on the gamma-ray bursts of the universe’s first billion years to shed light on the life cycle of the first stars. Although EnVision was recommended by the Higher Scientific Committee, it was also recognized that Theseus has a very compelling scientific argument that could make extremely important contributions in this field.
The next step for EnVision is to move into the detailed “definition phase,” in which the satellite and instrument design is finalized. After this design phase, a European industrial contractor will be selected to build and test EnVision before launching it on an Ariane 6 rocket. EnVision will have its first opportunity in 2031, with other options possible in 2032 and 2033. It is estimated to take about 15 months to reach the planet and another 16 to achieve the circularization of the orbit through aerobraking. Its 92-minute orbit will be quasi-polar with an altitude between 220 and 540 km. (Source: ESA)