STRANDED ON MARS

NASA spent years and billions of dollars collecting Martian samples to bring home. Now it might just leave them there

- BY JONATHAN O'CALLAGHAN

NASA's Perseverance Mars rover took this selfie on Mars in July 2024. The rover stands next to a rock named Cheyava Falls, which scientists say may hold clues about whether the planet ever hosted microbial life.

RIGHT NOW ONE OF THE MOST advanced planetary explorers ever built is scouring the surface of Mars. Supported by a team of hundreds of scientists back on Earth, the Perseverance rover has traveled nearly the distance of a marathon to answer some of the biggest questions about our neighboring world: What was the planet like eons ago? Was it ever habitable? Did it host life?

One rock visited by Perseverance, called Cheyava Falls, is speckled with iron-rich minerals that might be able to answer these questions, scientists announced in September. On Earth the presence of these minerals usually means microbes that used iron in the chemical reactions essential to their metabolism once lived there. Does the same hold true on Mars? A piece of Cheyava Falls is safely tucked inside the rover's storage cache. If it can be shipped to Earth, analysis with the full range of laboratory equipment here could tell us the answer.

But Cheyava Falls's ride to our planet might have fallen through. The Perseverance rover is the first phase of a multistep mission to bring bits of Mars to Earth known as Mars Sample Return (MSR), and the next step is dangling by a thread. The Trump administration has proposed canceling the return portion of the endeavor. The mission's fate, as of press time, rests with the U.S. Congress.

The situation has dismayed scientists who have longed to get their hands on Martian rocks. Now that Perseverance has scooped up prized samples, scientists are faced with the prospect of leaving them on Mars to languish.