Mars Sample Return at Risk — Perseverance’s Cheyava Falls Sample May Never Reach Earth

NASA’s Mars Sample Return Faces an Uncertain Future

One of the most sophisticated planetary explorers ever built, the Perseverance rover, continues to probe Mars with the support of hundreds of scientists on Earth. The rover has driven nearly a marathon’s distance across the Jezero Crater region to address key questions: What were Mars’ ancient environments like, was the planet ever habitable, and did it ever host life?

Why Cheyava Falls Matters

Among Perseverance’s finds is a sample nicknamed Cheyava Falls, collected in March 2024 from a region called Bright Angel. Scientists reported in September that the rock is speckled with iron-rich minerals and shows the team’s first confident detection of organic matter—features that on Earth are often associated with ancient microbial activity. A segment of Cheyava Falls is safely sealed inside one of the rover’s cigar-sized sample tubes; if returned to Earth, laboratory analyses could probe whether those features are biological in origin.

The Retrieval Step Is in Jeopardy

Perseverance is Phase 1 of the multi-step Mars Sample Return (MSR) campaign. The follow-up retrieval phase — designed to collect the cached tubes and deliver them to Earth for detailed lab study — is now uncertain. An independent review warned that the original retrieval plan could cost roughly $11 billion and slip into the 2040s. In response, NASA abandoned that initial architecture in 2024 and invited commercial and alternative proposals. In May 2025, the Trump administration proposed canceling MSR in its draft budget, describing the program as financially unstable; Congress will decide the final outcome.

What Perseverance Has Collected

Perseverance carries up to 43 sample tubes. As of July 2025 the rover had filled 33 tubes: 27 rock cores, two regolith samples, one atmospheric sample and three witness tubes used to verify cleanliness. Ten tubes were placed at a contingency cache called Three Forks (deposited December 2022–January 2023) to safeguard material if the rover fails later; other high-priority cores—such as Cheyava Falls—remain aboard the rover.

Why Returning Samples Matters

Earth laboratories offer instruments and techniques not possible on Mars mission payloads. Returned samples could reveal unambiguous biosignatures (for example, chemical patterns or microfossils difficult to explain by abiotic processes), provide precise rock ages that constrain Mars’ watery history, and preserve mineral magnetic signatures that map the planet’s core activity and atmospheric loss over time. If life existed on Mars, these returned rocks offer our best chance to prove it.

The Technical and Political Challenges

Humans have never launched a spacecraft from Mars. The original plan involved a lander, a small fetch rover (then planned from ESA), a Mars ascent vehicle to launch the samples into orbit, and an orbiter to return them to Earth. Because the fetch rover concept proved too heavy and the architecture grew costly and delayed, NASA sought new approaches and solicited proposals from commercial and international partners.

By late 2024 about a dozen proposals had been submitted. Commercial companies including SpaceX and Blue Origin reportedly proposed concepts (details are limited); Rocket Lab publicly suggested it could return samples for about $4 billion with a 2031 delivery if approved promptly. China’s Tianwen-3 mission also aims to collect and return Martian samples, with a planned launch in 2028 and a return by 2031, raising the prospect that another actor could bring the first Martian rocks to Earth.

Time Is Limited

Perseverance’s nuclear power source is expected to provide roughly another decade of operation, which sets a practical deadline for handing off samples to a stationary MSR lander if a fetch rover is not used. Kenneth Farley, Perseverance’s project scientist, warns that if construction of a return mission does not begin within about two years, the opportunity for a timely handoff will likely close—mission builds typically require four to five years or more.

The sealed sample tubes are durable and could preserve material for decades (estimates indicate up to ~50 years). If MSR is canceled or postponed indefinitely, Perseverance could deposit its cache on the surface for a future robotic or human mission to retrieve; another nation or commercial actor could also attempt recovery. Jim Green, former NASA chief scientist, notes there is nothing physically marking the tubes as U.S. property.

What’s Next

Congress will decide whether to follow the administration’s proposed cuts or fund an alternative MSR approach. Scientists and the planetary community largely consider sample return a top priority, but they disagree on cost, architecture and timing. Meanwhile, Perseverance continues to explore beyond Jezero, heading toward terrain that could contain some of the oldest materials yet encountered—a potential trove for understanding Mars’ earliest environment.

Bottom line: Perseverance has cached scientifically priceless samples, including Cheyava Falls, but political and budgetary decisions over the next two years will determine whether those rocks ever reach Earth laboratories.