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'Perseverance' Mission Will Put NASA Wheels Back On Mars


Last week, two international missions went into orbit around Mars. This week, another interplanetary vehicle will be looking for the perfect parking place on the ground. NASA's latest six-wheeled rover is set to touch down on the floor of the Jezero Crater, a spot which was once a Martian lake. The goal of the mission is - guess what? - to study rocks. The rover is called Perseverance. And NPR's Joe Palca tells us all about it.

JOE PALCA, BYLINE: The last rover to land on Mars was in 2012. That rover, called Curiosity, had this seemingly crazy landing system. After a heat shield and a parachute slowed things down, a jetpack called the sky crane took over. It lowered the rover to the surface on a cable. Crazy, but it worked. NASA engineer Al Chen says Perseverance's sky crane is new and improved. It has something called terrain-relative navigation that can detect potential hazards in the landing zone.

AL CHEN: So the vehicle will actually try to figure out, where is the nearest reachable safest landing spot that it can go to? - and then fly there.

PALCA: In other words, the sky crane will try to do what Neil Armstrong did when he realized his landing module was heading into a dangerous boulder field on the moon.

CHEN: It'll use its engines to fly up to about 700 meters or so in search of the best possible place that it can reach at that point.

PALCA: Once on the ground, Perseverence will start studying rocks.

BETHANY EHLMANN: That is what those of us who are geologists get trained to do - is give us a rock, and we'll tell you something about its history and the history of the planet.

PALCA: Bethany Ehlmann is a professor of planetary science at Caltech and president of the Planetary Society.

EHLMANN: Rocks really record the fingerprints of past processes. And so by looking at their textures and by looking at their minerals and chemicals, we really can piece together the conditions under which that rock formed.

PALCA: The rocks at Jezero Crater, where the rover is landing, should be interesting. Three and a half billion years ago, there was a lake in the crater. If there were microbes or some other form of life in the lake, they may have left behind those fingerprints Ehlmann mentioned. But let's say Perseverance does find a rock that looks like it might have something life-like preserved in it. Will that convince people there was once life on Mars? Probably not. That's why Perseverance is really the first part of a plan to return rock samples to Earth. The rover will put rock samples in tubes that a future mission will collect. Ehlmann says as capable as the instruments on Perseverence are, there are analyses that can only be done by labs on Earth. That's a lesson scientists learned from the NASA Apollo program.

EHLMANN: The moon rocks - you know, they're delivered back in the '60s, '70s, yet they're still - we're still discovering things in them. And that's because our instruments get better and better, and the questions we can ask get better and better.

PALCA: In addition to studying rocks, Perseverance will take pictures. Most of its nearly two dozen cameras have specific scientific or engineering roles critical to mission success. But NASA engineer David Gruel says they also put together a low-cost system for taking pictures during entry, descent and landing. That system uses parts bought on the Internet.

DAVID GRUEL: The camera is $400. It uses a off-the-shelf four-gigabyte memory chip that you would put into your camera at home.

PALCA: One of the cameras is mounted on that rocket pack called the sky crane. It will take video of the rover as the sky crane lowers it to the surface. Gruel says you should be able to see the rover's wheels drop into place, much like the landing gear on an airplane.

GRUEL: And then the jet engines start to kick up dust from the surface of Mars. As the vehicle disappears into that dust and gets ready to land on Mars, it's going to be awesome.

PALCA: And while we're on the topic of awesome, Perseverence is also carrying a small helicopter drone equipped with cameras that's supposed to fly over the landing site later this year. Those pictures should also be awesome. Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.

Joe Palca is a science correspondent for NPR. Since joining NPR in 1992, Palca has covered a range of science topics — everything from biomedical research to astronomy. He is currently focused on the eponymous series, "Joe's Big Idea." Stories in the series explore the minds and motivations of scientists and inventors. Palca is also the founder of NPR Scicommers – A science communication collective.