The Mars Sample Return Mission Is at a Dangerous Crossroads

Mars Sample Return has always been an expensive, high-risk, high-reward project. But now, with realization of the mission’s actual cost and expanding timeline, Congress must commit to fully supporting the effort or risk tanking the rest of NASA’s planetary science program

This illustration shows a concept for a Mars Ascent Vehicle (left) releasing a sample container (right) high above the Martian surface.

As part of a Mars sample return mission, a rocket will carry a container of sample tubes with Martian rock and soil samples into orbit around Mars and release it for pick up by another spacecraft.

NASA excels at bold projects. Consider the James Webb Space Telescope (JWST), which is rewriting cosmology and revealing profound insights into stellar evolution, along with precious views of our own solar system. Although JWST was notoriously over budget and delayed by a decade, who among us now would dare say that its $10-billion investment was not worth the cost and the wait?

But NASA’s latest big-ticket science project, the Mars Sample Return (MSR) mission, might not face such a happily-ever-after scenario. Even if it succeeds in bringing pieces of Mars back to Earth, it may do so by siphoning funds from other planetary science projects and scuttling the space agency’s well-laid plans for further exploration of the solar system.

Worse, if left underfunded during its current stage of development, MSR could face even longer delays and higher costs, the very cause of JSWT’s delay. This would stifle exploration of the Red Planet until the late 2030s.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


MSR will collect Martian rock and dirt samples from Jezero Crater, which is thought to have been flooded with water billions of years ago, and send them back to Earth. The NASA Perseverance rover, a first leg in this multipart show, has so far collected 23 of 38 planned samples and has left them in capsules on the Martian surface for retrieval. From there details become less certain, but current plans call for a future NASA-led Sample Retrieval Lander carrying two small helicopters and a rocket to snatch up these capsules and launch them into Mars orbit, where yet another MSR component, the Earth Return Orbiter, led by the European Space Agency (ESA), will be waiting to receive them and bring them home.

That plan is bold, for sure. Yet boldness comes at a cost. The price tag for the completion of this multiphase conception of the MSR mission is estimated to be $8 billion to 11 billion, eerily similar to that of JWST. The MSR independent review board (IRB) released findings and recommendations in September 2023 of a “near zero probability” of launching in the 2027–2028 window as hoped. A launch now is eyed for 2030, which is exceedingly optimistic. The board also determined that to meet that date, the mission would require an excess of $1 billion per year for three or more years starting in 2025—this news coming amid vast budget uncertainty caused, in part, by Congress not passing a full budget for 2024. A response panel plans a revised architecture by next March, and NASA has meanwhile slowed down work on the mission as of November 2023.

Planners would be wise to remember JWST’s recent history. Its primary problem during the early years of its development was a chronic underfunding that led to delays and cost overruns—a result of the unfortunate practice of deferring work into future years to stay within annual budget commitments, which were too low, according to JWST’s Independent Comprehensive Review Panel. NASA might be walking right back into this scenario with MSR if adequate funding proves hard to come by during the project’s developmental phase. Its uncertain, ballooning cost may then delay other queued up missions until after its launch.

Budget uncertainties have prompted NASA to announce a one-year delay in the Dragonfly mission, a helicopter destined for Saturn's moon Titan; a three-year delay in the VERITAS mission to Venus; and a three-year delay for a call for proposals for the next New Frontiers planetary science mission. With delays come the threat of losing precious talent. Also, check out the NASA aspirational time line for Mars. Little is cooking until the mid-2030s at best. Although JWST was derided as the “telescope that ate astronomy,” the project’s problems did not cause NASA’s entire astrophysics program to grind to a halt. During JWST’s development, the space agency flew a Hubble Space Telescope servicing mission and launched the Spitzer, Fermi and Kepler space telescopes, all world-class missions.

MSR is billed as a mission that could determine if Mars once harbored life, but finding a definitive biosignature may be a stroke of luck. Perseverance is digging down only about seven centimeters to take samples, whereas NASA’s own research suggests that cosmic radiation bathing Mars degrades organic chemicals such as amino acids down to nearly two meters below the surface. To strengthen our chances of finding extant life on Mars, we need to probe deeper and acquire samples that have been protected from surface radiation and extreme temperatures. And if the goal is chiefly to seek out fossilized remains near the surface, we need to sample wide stretches across the entire planet, beyond the narrow range of a single crater.

Interestingly, ESA hopes to send a probe to Mars in 2028 to indeed dig deep and search for life. Called the Rosalind Franklin rover, in honor of the x-ray crystallographer who helped uncover the structure of DNA, this mission will drill two meters below the Martian surface, far deeper than any before. ESA had teamed with Russia for the mission, but that country’s 2022 invasion of Ukraine effectively ended the collaboration. ESA has been forced to reconstruct many components, including a new lander. NASA has pledged support for components that include the propulsion system to land the Rosalind Franklin rover, but that funding may be in jeopardy if MSR cuts too deeply into its planetary exploration budget.

What, then, is a reasonable NASA goal for Mars exploration, given MSR’s unfortunate rising cost and inevitable delays? If the goal merely is to be the first to return a sample from Mars, then NASA is on a losing trajectory. China is planning to launch its own sample return mission, Tianwen-3, in 2028, with a Mars arrival date of 2030 and return to Earth in 2031. If the goal is to better understand the past and present habitability for life on Mars and humanity's future there, then NASA could redirect its resources and talent to ensure a successful Rosalind Franklin mission instead and also plan a series of smaller and more inexpensive missions to Mars—drillers, balloons or a next-generation helicopter building on the success of the Ingenuity copter that is now buzzing around Mars. During a meeting at NASA headquarters in March 2023, Eric Ianson, director of the NASA Mars Exploration Program, articulated this strategy of launching relatively low-cost missions in the $100-million-to-$300-million range every two years, when Earth and Mars are at their closest.

Laboring under the threat of cancelation, as the JWST team did, is demoralizing for workers. Yet MSR’s budgetary threat to a steady flow of missions is a blow to the broader planetary exploration program and the workers supporting it. If Congress doesn’t properly fund MSR now with adequate room for concurrent exploratory missions, then returning a sample from Mars might be only one of many firsts that China achieves—not only on the Red Planet but across the wider solar system.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.