NASA’s Mars Perseverance rover poses for a selfie after drilling a sample of Cheyava Falls, the arrowhead-shaped rock at the center of this photo. Credit: NASA/JPL-Caltech/MSSS
Far away on the desolate planet Mars, a collection of dust and rock samples await a journey that may never arrive.
After years in limbo, NASA’s groundbreaking Mars Sample Return (MSR) program, supposed to transport Martian materials collected by the Perseverance rover to Earth, appears on the verge of cancellation. Earlier this week, a bipartisan group of U.S. lawmakers passed a spending bill that focuses on the MSR program, which would have been the first mission to bring Martian samples to Earth.
Rocks from Mars are waiting to be transported to Earth: can NASA deliver?
The end of the mission did not come out of nowhere. The estimated cost of this ambitious project has skyrocketed, reaching $11 billion in 2023, an amount similar to that of building the James Webb Space Telescope. And early last year, NASA admitted that it still had no concrete plan to return the Martian samples to Earth. US President Donald Trump’s administration has sought to cancel the MSR project as well as many other NASA science missions.
Fortunately for many scientists, the bill restores funding for the vast majority of NASA space science missions that the administration’s budget proposal had put on the chopping block, such as the Habitable Worlds Observatory space telescope, which would search for signs of life on planets outside the solar system. As a result, the bill, which still must be approved by the Senate, “ultimately is a good bill for NASA science,” says Casey Dreier, chief of space policy at the Planetary Society, a nonprofit in Pasadena, California.
But many scientists were disappointed by MSR’s fate. “I was certainly disheartened to hear the news,” says Ryan Ogliore, a planetary scientist at the University of Central Florida in Orlando. “But I wasn’t surprised by what we had heard over the last two years.”
Asked for comment, NASA did not respond before publication.
Here Nature looks at the scientific opportunities that will be lost due to program cancellation and the prospects for relaunching a mission.
Good deal on biosignature
Among the most tantalizing samples collected by Perseverance is number 25, taken from a rock called Cheyava Falls. In September last year, NASA announced that the rover had discovered places on the rock surface containing two chemical compounds found on Earth around decaying matter and which are produced by some forms of microbial life.1. These compounds, the researchers suggest, could be a fingerprint of ancient microbial life.
Mars rover makes epic ascent to explore some of the solar system’s oldest rocks
But these compounds can also be produced without the participation of living beings. As long as the Cheyava Falls sample remains on Mars, scientists will not be able to fully analyze it to learn its origins. “This sample is worth several billion dollars because it can answer this existential question that humans have been asking since the dawn of time,” explains Ogliore.
