Now it’s official: After more than three decades of neglect, NASA is returning to the planet Venus with two robotic missions. Called DaVinci + and Veritas, they represent the first forays of the American space agency into the second world after the sun, our closest planetary neighbor, since the Magellan mission (Magellan), which started in 1989 and ended in 1994.
Venus is similar in size to Earth, but suffers from a hundred times denser atmosphere and an overwhelming greenhouse effect that raises the average temperature of the planet to 460 degrees Celsius. He is something like the “bad twin” of our world and an uncomfortable reminder of what can go wrong with planets that are otherwise very similar to ours.
However, this was not always the story. It is quite possible that in the beginning 4 billion years ago when the solar system was young, Venus was friendlier and perhaps even harbored oceans. The DaVinci + mission with its orbiter will examine the Venusian atmosphere just to look for clues to the past existence of these now vanished seas.
The project will also include an atmospheric probe that penetrates the gas envelope around Venus and studies its composition. Interest in these results, as well as those obtained in orbit, has increased recently after a group from Cardiff University presented evidence last year that a compound called phosphine might be present in clouds of Venus at this level of atmospheric pressure and temperature mild. The evidence and its significance are still hotly debated by the astrobiology community, but some believe it could be evidence of microbial life that is still present in the air of Venus today.
The other mission chosen, Veritas, is an orbiter equipped with powerful radar to study the surface of Venus and its geological structures. It was supposed to repeat Magellan’s mapping effort, but this time with much higher resolution. (It is worth remembering that Venus is completely covered in thick clouds all the time, so the only way to map the surface with high resolution from orbit is with radar systems.)
The two missions were selected as part of the Discovery program that NASA sponsors to conduct interplanetary probes with limited goals and lower costs. Your budget, other than implementation, cannot exceed $ 500 million. Comparable is the Mars rover Perseverance, which cost the agency a total of 2.8 billion US dollars on a mission classified as a flagship.
It is the second time that both have reached the final stage of the selection process; in the last round in 2017, the two were eventually passed over for missions on asteroids (Lucy and Psyche, which are scheduled to fly in 2021 and 2022). In the competition, they proposed two other proposals, the IVO orbiter, which was aimed at Jupiter’s moon Io, and the Trident mission, which was supposed to fly over Triton, the largest of Neptune’s moons. (In the first selection phase, in 2020, the Sidereal Messenger bet that at least one Venusian would win.)
NASA says the launches should take place between 2028 and 2030. There is still a long way to go before then. The fact is, however, that after many decades the agency has turned its gaze to Venus. According to Magellan, the planet received the orbiters Venus Express (from ESA, European Space Agency), launched in 2005 and destroyed in 2015, and Akatsuki (from Jaxa, Japan), launched in 2010 and still operational despite being in one limited orbit are results. This comes on top of the occasional visits from passing spacecraft like the BepiColombo, whose final destination is Mercury but which flew over Venus last year and will do another one this year.
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