WAILEA, Hawaii — NASA is delaying plans to move the Mars Sample Return (MSR) program to its next phase of development after an independent review found serious issues with its technical readiness, cost and schedule.

NASA released Sept. 21 the final report of an independent review board it commissioned earlier this year to examine the state of the program to pick up samples cached by the Perseverance rover and return them to Earth. That review was chaired by Orlando Figueroa, former director of Mars exploration at NASA.

The report concluded there was “a near zero probability” that the two main elements of MSR, a sample retrieval lander developed by NASA and an Earth return orbiter developed by the European Space Agency, will be ready for launch in 2027 or 2028 as currently projected. Projected budgets for MSR, the report added, are also insufficient.

“MSR was established with unrealistic budget and schedule expectations from the beginning,” the report stated. “As a result, there is currently no credible, congruent technical, nor properly margined schedule, cost, and technical baseline that can be accomplished with the likely available funding.”

NASA had yet to set a formal cost estimate for MSR, something that had been planned for a confirmation review this fall. A previous independent review in 2020 estimated MSR would cost $3.8 billion to $4.4 billion, which itself was a significant increase over earlier estimates. A report this summer said that cost estimates had grown to $8 billion to $9 billion, a range the agency then called “highly speculative.”

The new independent review says the likely range of full lifecycle costs for MSR is now between $8 billion and $11 billion, significantly more than expected based on NASA budget projections. “The current reference architecture is not viable within the likely available funding profile,” it stated. That new range is unlikely to change even if NASA changes the overall architecture for MSR, the report added.

The simplest alternative, moving the launch of the lander and orbiter to 2030, would create a total cost between $8 billion and $9.6 billion. That approach, though, would require spending more than $1 billion a year between fiscal years 2025 and 2028, putting greater budget pressures on the overall NASA planetary science portfolio.

The study examined alternative architectures that the report provided few details about, but would involve replacing the single sample retrieval lander with two landers using previously flown technologies, like the “skycrane” landing system. The total cost of those architectures would be as high as $10.9 billion, but with lower annual costs and with launches as late as 2035.

The report also identified technical issues, including with the design of what’s called the Orbiting Sample, which contains the samples that are launched into Mars orbit. “The lack of a well-defined Orbiting Sample (OS) design continues to impact and constrain many MSR systems,” the report stated, including questions about ensuring planetary protection.

Despite the technical and programmatic problems, the review nonetheless endorsed the scientific value of MSR. The report offered a recommendation that NASA find a way to return all the samples that have been collected so far by Perseverance, not just a subset of 10 sample containers the rover placed in a region of Jezero Crater called Three Forks earlier this year as a backup.

“The cache of samples deposited at Three Forks is return worthy but is not an optimal sample set because it does not represent the full diversity of geologic environments along the rover’s traverse that could preserve signs of life,” the report stated. “The 20 samples now collected by and carried on Perseverance are of very high scientific value – higher than the cache at Three Forks.”

It also called on NASA to communicate the importance of MSR more effectively: “NASA is not sending a consistent and unified message to Congress, the scientific community, and to the public regarding MSR’s scientific and strategic importance to the nation.” That includes the “soft power” benefits of accomplishing a mission as complex as MSR as China works on its own effort to return samples from Mars around 2030.

In a statement issued in conjunction with the release of the report, NASA said it was holding off performing the MSR confirmation review scheduled for this fall. Instead, a team led by Sandra Connelly, NASA deputy associate administrator for science, will review the report and make a recommendation on the future of MSR “within a balanced overall science program.” That recommendation is expected between January and March 2024.

“We thank the board for its work, and now our job is to assess the report and address if there are elements of the program that need to change,” Connelly said in the statement.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...