NASA’s latest Mars rover is approaching its final descent to the surface. Perseverance, the largest vehicle ever to attempt to land on the Red Planet, is due to touch down on 18 February.
Landing on Mars is difficult: about 60 per cent of the missions that have tried it to date have failed. Perseverance will have a similar landing sequence to the Curiosity rover, which arrived successfully in 2012, with a heat shield and parachute slowing it down from about 20,000 kilometres per hour to less than 4 kilometres per hour before a “sky crane” lowers the vehicle gently to the ground.
Perseverance will land in Jezero crater, thought to be a dry lake bed, but we don’t know the exact spot. “Once you hit Mars’s atmosphere, the wind buffets you around and makes it harder to predict,” says Briony Horgan at Purdue University in Indiana, part of the Perseverance team. Because of that and the rugged landscape, Jezero was thought to be too dangerous to land in – but Perseverance has a new navigation system that will take pictures as it nears the surface and autonomously pick a safe-looking landing spot.
Part of Perseverance’s scientific goal is to look for evidence of current or past life on the Martian surface. However, even with its sophisticated scientific instruments it is unlikely that the rover will be able to confirm signs of life with 100 per cent certainty.
“The hope is we’ll find very strong evidence – layers of organic material layered in with microbial mat textures on an ancient shoreline, something like that,” says Horgan. “But we still need to check and make sure that some weird non-biological thing didn’t cause this, and to do that we really need to bring samples back to Earth and look at them in the lab.”
That is why the other part of the mission is to grab samples of dust and rocks, carefully package them in 43 test tubes the rover carries in its belly and leave them behind on the surface of Mars. Then, another mission that is currently planned for 2026 will pick them up and bring them back to Earth.
“If it sounds complicated, it is. If it sounds extreme, it most certainly is,” said Lori Glaze, NASA’s director of planetary science, in a press conference. But all that complexity will be worth it, she said. “We expect samples of Mars to provide new knowledge for decades to come as we study them with state-of-the-art laboratory tools we couldn’t possibly carry to Mars right now.”
Scientists still study the rocks that the Apollo missions brought back from the moon between 1969 and 1972, and these new Mars samples could provide a similar way to conduct in-depth studies of the Martian surface from laboratories on Earth.
Bringing the samples back also has another benefit: it may act as a sort of dress rehearsal for crewed missions to Mars, which will presumably mean bringing people back from the Red Planet after sending them there. “Perseverance is the first leg of the first-ever round trip to another planet,” said Wanda Peters of NASA’s Science Mission Directorate during a briefing. If the landing goes smoothly, that round trip will be well on its way.
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