America was winning the race to find Martian life. Then China jumped in.

To most people, rocks are just rocks. To geologists, they are much, much more: crystal-filled time capsules with the power to reveal the state of the planet at the very moment they were forged. 

For decades, NASA had been on a time capsule hunt like none other—one across Mars.

Its rovers have journeyed around a nightmarish ocher desert that, billions of years ago, was home to rivers, lakes, perhaps even seas and oceans. They’ve been seeking to answer a momentous question: Once upon a time, did microbial life wriggle across its surface? 

Then, in July 2024, after more than three years on the planet, the Perseverance rover came across a peculiar rocky outcrop. Instead of the usual crystals or layers of sediment, this one had spots. Two kinds, in fact: one that looked like poppy seeds, and another that resembled those on a leopard. It’s possible that run-of-the-mill chemical reactions could have cooked up these odd features. But on Earth, these marks are almost always produced by microbial life.

But the only way to confirm whether these seeds and spots are the fossilized imprint of alien biology is to bring a sample of that rock home to study. 

Perseverance was the first stage of an ambitious scheme to do just that—in effect, to pull off a space heist. The mission—called Mars Sample Return and planned by the US, along with its European partners—would send a Rube Goldberg–like series of robotic missions to the planet to capture pristine rocks. The rover’s job was to find the most promising stones and extract samples; then it would pass them to another robot—the getaway driver—to take them off Mars and deliver them to Earth.

But now, just over a year and a half later, the project is on life support, with zero funding flowing in 2026 and little backing left in Congress. As a result, those oh-so-promising rocks may be stuck out there forever. How did this happen?