MSR faces cancellation — time is of the essence.

NASA's Mars Sample Return mission is facing some tough scrutiny.

The Senate Appropriations Committee offered their recommendations on the spending bill for fiscal year 2024, and they do not provide all NASA was hoping for. The Commerce, Justice and Science (CJS) spending bill, which allocates funds for NASA and a few other government agencies, was reviewed by the committee in a 28 to 1 vote on July 13. The bill secures funding for NASA's ongoing Artemis program to the moon and other exploration initiatives, but cuts the space agency's budget for planetary science by over half a billion dollars.

In opening remarks, Senator Patty Murray stated the bill was, "written under some very difficult limitations," adding her stance that "those caps limit our ability to invest in our country's future."

First on the Committee's chopping block seems to be NASA's ambitious Mars Sample Return mission (MSR), a plan to retrieve Martian geological specimens collected by the Perseverance rover. The report raises concerns with the mission's continually delayed timeline and increasing costs. A recent Ars Technica report details ballooning internal cost projections for MSR at NASA, nearly doubling the mission's overall estimate to between $8 and $9 billion.

The Senate Committee's report indicates their concern that MSR is taking priority over other critical path NASA missions, stating, "the Committee has significant concerns about the technical challenges facing MSR and potential further impacts on confirmed missions, even before MSR has completed preliminary design review."

The report gives NASA 180 days following the bill's enactment to provide a year-by-year budget break-down for MSR that fits into the $5.3 billion lifecycle cost outline included in the 2022 Planetary Science Decadal Survey. If the space agency misses the deadline, or fails to reduce costs to fit within the proposed budget, the mission could face cancelation. The Committee also took the liberty to suggest programs where those funds might be reallocated, should that cancelation take place. They include the Artemis campaign, the Dragonfly mission, and a "flagship orbiter and probe" mission to Uranus.