One full redesign later, Mars Sample Return still hasn't set a budget
Summary
Mars Sample Return (MSR) -- NASA and the European Space Agency's plan to bring Martian rock samples to Earth -- is one of NASA's most ambitious science missions. In February 2024, NASA's Inspector General found the program's cost estimate had grown from $2.5-3 billion in 2020 to an unofficial $7.4 billion by mid-2023, with its lead hardware's design review running 14 months late, as the program approached the review meant to set a formal cost and schedule baseline. An independent review board went further that September, concluding the program's original design couldn't stay within budget or return samples before 2040. NASA spent over a year soliciting alternatives before announcing, in January 2025, a completely redesigned, cheaper mission architecture targeting under $11 billion and a 2035 return. By GAO's July 2025 assessment of NASA's major projects, though, MSR's cost and schedule were both still listed as 'under review' -- one of three major NASA projects where GAO found baseline-setting had simply been delayed.
A cost estimate that nearly tripled before a baseline was even set
MSR's life-cycle cost estimate grew from $2.5-3 billion in July 2020 to $6.2 billion at its KDP-B review in September 2022 to an unofficial $7.4 billion by June 2023 -- a 196% increase from the low end of the 2020 range, before the program had even reached the review meant to formally lock in a budget. The Inspector General was blunt about why: intrinsic factors like the mission's complexity and "initial over-optimism," not just the COVID-19 pandemic, inflation, or supply chain issues had pointed to.
View data as table
| 2020 estimate (low end of $2.5-3B range) | 2.5 |
|---|---|
| 2022 estimate (at KDP-B review) | 6.2 |
| 2023 estimate (unofficial) | 7.4 |
The hardware told the same story. The Capture, Containment, and Return System -- the piece of equipment that grabs the sample container in Mars orbit -- had its Preliminary Design Review planned for October 2022. It didn't happen until December 2023: 14 months late, adding about $200 million to the budget and a year of lost schedule. Between that and other delays, the program's own key decision point, originally set for August 2023, still hadn't happened as of the audit.
Four recommendations, two of them not quite settled
The Inspector General made four recommendations -- chiefly, that the program establish a stable design and properly account for its own complexity and track record, rather than blaming external factors, before setting its cost and schedule baseline. concurred with three and partially concurred with the fourth. But the 's own evaluation drew a distinction: two recommendations it considered resolved outright, and two -- including the core one, about establishing a stable design before locking in a baseline -- it said would need further discussion and documentation before being closed, even though it found 's response "responsive."
View data as table
| Resolved, to be closed on verification | 2 |
|---|---|
| Needing further discussion before closing | 2 |
An independent board said the original plan simply wouldn't work
The clearest confirmation came from outside 's own program office. A September 2023 independent review board concluded MSR's existing architecture could not stay within its planned budget or return samples before 2040 -- years later than anyone had been planning for. spent the following months soliciting industry and -community input, receiving 12 study reports on alternative approaches, before announcing in January 2025 that it would scrap the original design in favor of a -led effort built on proven, "heritage" technology, with a commercial landing option also under consideration. The new target: total life-cycle costs under $11 billion, with samples returned as early as 2035. The program's lead office was also moved from the Jet Propulsion Laboratory to Headquarters, at the review board's recommendation, to improve oversight.
View data as table
| Unofficial estimate, original architecture (mid-2023) | 7.4 |
|---|---|
| Cost ceiling NASA set for the redesigned architecture (Jan. 2025) | 11 |
Sixteen months, one full redesign, still no baseline
By 's July 2025 assessment, MSR's preliminary schedule and preliminary cost were both listed simply as "under review." 's broader review of 's project-management improvements noted that the agency had delayed setting cost and schedule baselines for three major projects -- the SLS Block 1B rocket upgrade, MSR, and the ML2 mobile launch tower -- until their requirements were more stable. For MSR, that meant a program the Inspector General had flagged for lacking a credible baseline in February 2024 still didn't have one 16 months later, even after abandoning its original design entirely.
The takeaway
- The Inspector General's warning wasn't about a single bad estimate -- it was about a pattern. Cost nearly tripled, the lead hardware's design review ran over a year late, and 's own program office acknowledged it likely couldn't meet the cost and schedule targets set just one review earlier.
- An outside board confirmed the worst case. The original architecture, per the September 2023 independent review, couldn't stay on budget or return samples before 2040 -- prompting to scrap it entirely rather than try to salvage it.
- Even a full restart didn't produce a baseline. Sixteen months after the Inspector General's warning, and after adopting an entirely different, cheaper mission architecture, found MSR's cost and schedule were still listed as under review -- not yet the credible, locked-in commitment the original audit said the program needed.
Findings on MSR's 2020-2023 cost growth, the CCRS design-review delay, the September 2023 independent review board's findings, and the 's recommendations and their status are from Report -24-008, 'Audit of the Mars Sample Return Program' (February 28, 2024), read directly in full from the Inspector General's website. Findings on 's 2025 architecture redesign, its new cost/schedule targets, and the program's still-unset baseline are from -25-107591, 'Assessments of Major Projects' (July 2025), read directly in full via an archived copy after the current gao.gov asset URL blocked direct access; this report covers 38 projects in total, and only its MSR-specific assessment and a related -wide finding are used here. The two reports examine the same program about 16 months apart -- the first warning that MSR's cost and schedule practices weren't credible, the second confirming that even a full architecture overhaul hadn't yet produced a formal baseline.
Sources(2) ▾
- NASA Office of Inspector General, Audit of the Mars Sample Return Program (2024-02-28) — -24-008 (A-23-01-00-SARD), an audit finding the Mars Sample Return (MSR) program's cost estimate had grown from $2.5-3 billion (2020) to $7.4 billion (unofficial, mid-2023), with its Capture, Containment, and Return System's design review over a year late, as the program approached a key decision point without a stable design -- the warning facet. Distinct from doc-gao25-107591 (the confirmed-outcome facet, published about 16 months later). Direct fetch of this PDF URL succeeded (HTTP 200). oig.nasa.gov · original document
- U.S. Government Accountability Office, NASA Assessments of Major Projects (2025-07-01) — -25-107591, 's annual omnibus assessment of 's major projects, containing a dedicated two-page assessment of Mars Sample Return -- the confirmed-outcome facet, published about 16 months after doc-oig-ig24008's warning, finding scrapped the original MSR architecture for a cheaper one and that a cost/schedule baseline still had not been set for either. This report covers 38 projects in total; only its MSR-specific assessment and its -wide baseline-delay finding (which names MSR alongside two other projects) are used here. Direct gao.gov PDF fetch returns HTTP 403; fetched in full via an archived copy. gao.gov · original document
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Mars Sample Return is a joint /European Space Agency mission to retrieve Martian rock samples already being collected by the Perseverance rover and bring them back to Earth for study. In February 2024⧉, 's Inspector General audited the program as it approached a key decision point meant to set its formal cost and schedule baseline. In July 2025⧉ -- about 16 months later -- 's annual assessment of 's major projects checked back in.