In February 2021, NASA’s Perseverance rover made a groundbreaking touchdown inside Mars’s Jezero Crater, a 28-mile-wide basin carved by ancient rivers and lakes. This landing marked the first phase of an ambitious mission to collect rock and soil samples from the Red Planet, with the ultimate goal of bringing them back to Earth for detailed analysis. Scientists hope these samples will answer some of humanity’s most profound questions about Mars: Was it ever habitable? Did microbial life ever exist there? And what happened to the planet’s atmosphere and magnetic field?
For decades, planetary scientists have dreamed of returning Martian samples to Earth. Robotic explorers and orbiters can only do so much; many critical analyses require the sophisticated, sensitive instruments that exist only in terrestrial laboratories. Since the 1960s, researchers have been lobbying for a Mars Sample Return (MSR) mission. Perseverance’s successful landing and sample collection represented a significant milestone toward realizing that vision. Yet, despite years of effort and billions of dollars invested, the future of this mission now hangs in the balance.
One of the most promising samples collected by Perseverance comes from a rock dubbed Cheyava Falls. This rock is speckled with iron-rich minerals that, on Earth, are typically associated with microbial life that used iron in metabolic processes. The presence of organic matter in Cheyava Falls, detected confidently by Perseverance’s instruments, hints at the tantalizing possibility of ancient life on Mars. If these samples can be returned to Earth, scientists will be able to rigorously test for biosignatures—chemical or physical signs of past life—using a broad array of laboratory tools.
However, the mission to bring these precious Martian samples back home is jeopardized by political and budgetary challenges. In April 2024, Bill Nelson, then NASA administrator, announced the postponement of the sample return phase. An independent review warned that the mission’s cost could balloon to $11 billion, nearly double the initial estimate, and that it could be delayed until 2040. Faced with these projections, NASA decided to scrap the original plan—which involved a complex sequence of spacecraft and a fetch rover built by the European Space Agency—and instead seek more affordable commercial options.
These commercial proposals include offers from major space companies such as SpaceX, Blue Origin, and Rocket Lab. SpaceX’s plan reportedly involves using its large Starship rocket, still under development, while Rocket Lab claims it could complete the mission for about $4 billion with a return in 2031 if approved soon. The agency received about a dozen proposals and is considering multiple options but has yet to select a definitive path forward.
This uncertainty has left the scientific community frustrated and anxious. Many researchers have dedicated their careers to the Mars Sample Return mission, seeing it as a top priority for planetary science. Vicky Hamilton, a planetary geologist, expressed her disappointment at the prospect of leaving valuable samples stranded on Mars. Briony Horgan, a planetary scientist, highlighted the excitement around the Bright Angel samples, which include Cheyava Falls, as they have the greatest potential to reveal biosignatures.
The stakes extend beyond the search for life. Mars once had a thick atmosphere and a protective magnetic field, conditions that made its surface warm and wet around three to four billion years ago. Understanding when and why Mars lost its magnetic field and atmosphere can shed light on planetary evolution and habitability. For example, measurements of magnetic orientation locked into rock samples can act as a “fossil record” of the planet’s magnetic history. This knowledge could inform our search for habitable exoplanets elsewhere in the galaxy.
The original Mars Sample Return plan was ambitious and complex. It envisioned sending a lander with a fetch rover to collect Perseverance’s samples and load them into a rocket that would launch from Mars into orbit. Another spacecraft orbiting Mars would then capture the sample container and bring it to Earth. However, this plan encountered major technical hurdles, especially with safely landing the heavy fetch rover, leading NASA to reconsider.
Meanwhile, China is pursuing its own Mars sample return mission, Tianwen-3, aiming to launch in 2028 and return samples by 2031. If NASA delays further, China could become the first to bring Martian rocks to Earth, adding an international dimension to the race to unlock Mars’s secrets.
In May 2025, the Trump administration proposed NASA’s 2026 budget, which