NASA’s Mars Sample Return program has been effectively cancelled, meaning the best evidence of life on Mars could be trapped in rock samples that NASA no longer has the budget to collect.
On Monday (Jan. 15), the U.S. Senate approved a spending bill that reverses the Trump administration’s decision to halve federal spending on science and slash NASA’s budget by nearly a quarter.
“The agreement does not support the existing Mars Sample Return (MSR) program,” lawmakers wrote in an accompanying report published on Jan. 6.
There’s no guarantee that life ever existed on Mars, but if it did, then the Perseverance rover may already have the evidence. This makes the new bill a major blow to those hoping to examine Perseverance’s haul of more than 30 geological samples, which includes a sample NASA described as “the clearest sign of life” ever found on Mars.
But bringing samples from Mars back to Earth was always going to be a costly endeavour, and the MRS program has been fraught with delays and spiraling costs. In January 2025, an independent review board calculated that the price tag could swell to $11 billion, with samples not expected back on Earth until 2040.
In a major overhaul of the program, NASA announced that it would pursue two different strategies for fetching the samples: a tried and tested landing system that deployed a rocket-powered sky crane at a total estimated cost of between $6.6 billion and $7.7 billion, and a commercial option whose price would fall somewhere between $5.8 billion and $7.1 billion. NASA planned to announce a decision between these options in the latter half of 2026.
Yet while the Senate’s move ostensibly supports the White House’s bid to kill the program, the funding bill could leave NASA space to revive the MSR. The bill, which recognizes that technologies developed as part of the MSR program were critical to the success of future space missions and human exploration of the moon and Mars, allocates $110 million to the Mars Future Missions program, including existing MSR efforts for “radar, spectroscopy, entry, descent, and landing systems, and translational precursor technologies.”
In other words, there’s funding for some of the tech that the program was working to develop, while falling far short of the total estimated mission costs. The allocation of $110 million nevertheless gives hope for the future of sample return, according to The Planetary Society, which campaigned against more severe proposed cuts to NASA’s science program.
The new bill pledges $24.4 billion to NASA, with $7.25 billion of that assigned to the space agency’s Science Mission Directorate. That means Congress only cut the NASA science portion of the budget by 1% compared to last year — a significantly more modest reduction than the 47% cut proposed by the Trump administration.
Lawmakers also committed funds to other NASA science projects in the bill. The agreement allocates $500 million for the Dragonfly mission to Saturn’s moon Titan, $208 million for the active James Webb Space Telescope and $300 million for the recently completed Nancy Grace Roman Space Telescope, which is set to hunt for alien worlds and search for the true nature of dark matter when it launches as early as this fall.
The funding bill now awaits President Trump’s signature to become law.
If the U.S. does abandon the dream of returning samples from Mars, it will leave China without competition. China’s Tianwen-3 sample return mission aims to collect fewer samples in a more accessible and less promising site than where Perseverance has looked for potential signs of life. However, the Tianwen-3 mission is scheduled to launch in 2028 and return rocks in 2031. If sample return is a race, then China could be set to win it.
“It is difficult to understand how the cancellation of MSR is anything but an admission that returning samples from Mars is too hard for the United States,” Victoria Hamilton, leading space scientist at the Southwest Research Institute and chair of the Mars Exploration Program Analysis Group (MEPAG), told Live Science’s sister-site Space.com on Jan. 12. “How do we expect to be successful at something orders of magnitude more ambitious and costly as the Moon to Mars program, where human lives are at stake?”
