Mars Sample Return Faces Budgetary Red Tape Amid Scientific Disappointments

The Mars Sample Return (MSR) program, which was set to bring samples of Martian rocks collected by the Perseverance rover to Earth for the first time, is facing the threat of permanent termination. Last week, a bipartisan group of American legislators approved a budgetary bill that excludes funding for MSR. The document still needs to be approved by the Senate, but as it stands, it essentially marks the end of one of the most ambitious projects in planetary science history.

By 2023, the estimated cost of MSR had risen to $11 billion-comparable to the expenses for developing the James Webb Space Telescope. At the beginning of 2025, NASA admitted that the agency still lacked a clear technical plan for returning the samples to Earth. The Trump administration had previously proposed canceling MSR along with several other NASA scientific programs.

Nevertheless, the bill restores funding for the majority of space science missions that were earlier proposed for cuts, including the Habitable Worlds Observatory telescope intended to search for signs of life beyond the Solar System. According to Casey Dreyer, head of the space policy division at the Planetary Society, the document is “ultimately a good bill for NASA’s scientific programs,” despite MSR’s fate.

For many scientists, the mission’s cancellation is a serious blow. “I am certainly upset by this, but not surprised-we’ve heard alarming signs over the past couple of years,” said planetary scientist Ryan Ogliore from the University of Central Florida. NASA had not responded to a request for comment by the time of publishing.

One of the major scientific losses may be the inability to fully analyze the most interesting samples collected by Perseverance. Among them is Sample No. 25 from the Cheyava Falls formation. In September of last year, NASA reported that two chemical compounds were found in this formation, often associated with the decomposition of organic matter and microbial activity on Earth. However, such compounds can also occur without life, and without returning the sample to Earth, it’s impossible to determine their origin. According to Ogliore, this sample is “worth several billion dollars because of the volume of answers it can provide to one of humanity’s key questions.”

The cancellation of MSR impacts not only fundamental science but also the prospects for manned missions. The U.S. administration is aiming to return humans to the Moon and subsequently make a way to Mars, but without analyzing Martian rocks, potential risks to astronauts remain unclear. As planetary geologist Victoria Hamilton from the Southwest Research Institute points out, chemical analysis of samples could help assess possible dangers and reduce both risks and engineering costs for future missions.

Moreover, samples from Mars could shed light on the planet’s formation history. Scientists had hoped to reconstruct key stages in the evolution of the Martian crust through isotopic markers and compare them with the well-studied chronology of the Moon. Without this data, the Moon remains the only object from which the early history of the inner Solar System can be reconstructed.

A complete refusal to deliver samples does not yet mean they will remain on Mars forever. The bill allocates $110 million to the Mars Future Missions program, which will continue to develop technologies related to MSR. Lockheed Martin has already expressed readiness to propose a sample return option for less than $3 billion. However, as Dreyer emphasizes, “the program as we knew it is dead.”