NASA's Perseverance Mars rover is wrapping up its prime mission on the Red Planet.
The car-sized Perseverance rover landed on the floor of Mars' Jezero Crater on Feb. 18, 2021, kicking off an ambitious surface mission designed to last one Red Planet year, which is about 687 Earth days.
That time is now up; the Mars calendar turned for Perseverance on Friday (Jan. 6). But don't fret: The six-wheeled robot will transition seamlessly into an extended mission on Saturday (Jan. 7).
Related: 12 amazing photos from the Perseverance rover's 1st Earth year on Mars
Perseverance has two main tasks on the Red Planet. The rover is hunting for possible signs of Mars life on the floor of the 28-mile-wide (45 kilometers) Jezero, which hosted a big lake and a river delta billions of years ago. Perseverance is also collecting and caching dozens of samples, which a joint NASA-European Space Agency (ESA) campaign will bring to Earth for detailed study in the early 2030s, if all goes according to plan.
That campaign will launch a rocket-toting NASA lander as well as an ESA Earth-return orbiter to the Red Planet in the mid to late 2020s. The plan calls for Perseverance to drive its samples over to the lander; the rocket will then launch the precious cargo to Mars orbit, where the ESA probe will snag it and haul the material back to Earth.
Perseverance has made a lot of progress on the sampling front to date. The rover has already filled up and sealed 18 of its 38 titanium sampling tubes as well as three of its five "witness tubes," which will help mission team members assess the cleanliness of Perseverance's sampling system.
And the rover has begun caching samples, too, to date dropping four of a planned 10 tubes on a patch of Jezero's floor that the mission team calls Three Forks. This depot is a backup, to cover for the possibility that Perseverance won't be able to ferry its samples to the lander when the time comes. (The rover is in good shape now, but there's no guarantee its health will hold through the end of the decade.)
In that case, two small helicopters that will launch aboard the lander will fetch the sample tubes from the depot one by one.
With this hedge in mind, the mission team has been collecting two samples from each of its target rocks. Perseverance is keeping one set on board and caching the other set.
The fetch helicopters will be based heavily on Ingenuity, the 4-pound (1.8 kilograms) chopper that traveled to Mars with Perseverance.
Ingenuity's main job was to show that aerial exploration is possible on Mars despite the planet's thin atmosphere, which is just 1% as dense as that of Earth at sea level. The little rotorcraft quickly achieved that goal during a five-flight demonstration campaign and is now serving as a scout for Perseverance on an ambitious extended mission.
Ingenuity now has 37 flights under its belt, which together have covered a total of 4.7 miles (7.6 kilometers). Perseverance, for its part, has racked up nearly 8.7 miles (14.0 km) of off-Earth driving, and that total will climb considerably during its extended mission.
After it finishes dropping samples at the Three Forks depot, Perseverance will head for the top of Jezero's ancient river delta, likely finishing the climb in February. The rover will then explore the region for the next eight months or so, looking for, among other things, rocks that were washed into the crater by Jezero's ancient river.
"The Delta Top Campaign is our opportunity to get a glimpse at the geological process beyond the walls of Jezero Crater," Perseverance deputy project scientist Katie Stack Morgan, of NASA's Jet Propulsion Laboratory in Southern California, said in a statement last month.
"Billions of years ago, a raging river carried debris and boulders from miles beyond the walls of Jezero," she said. "We are going to explore these ancient river deposits and obtain samples from their long-traveled boulders and rocks."
Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook.