WASHINGTON — House appropriators would fully fund NASA’s Mars Sample Return program despite its ongoing problems but halt the agency’s plans to cooperate with a European Mars mission.

House appropriators released this week the report accompanying the commerce, justice and science (CJS) spending bill for fiscal year 2024. That bill, which includes $25.366 billion for NASA, had been in limbo for more than three months, after an appropriations subcommittee marked up the bill in mid-July. The full appropriations committee did not take up the bill at the time nor public the report associated with it, which provides more details on spending levels and policy direction.

The delayed publication of the report comes as the full House prepared to take up the bill without an appropriations committee markup, likely in mid-November. The House Rules Committee is soliciting amendments for the bill now for consideration some time during the week of Nov. 13.

The biggest difference between the House and Senate bills involves Mars Sample Return (MSR). The Senate bill provided only $300 million for the program, less than a third of NASA’s $949.3 million request, and directed NASA to provide a funding profile for MSR that costs no more than $5.3 billion or provide “options to de-scope or rework MSR or face mission cancellation.”

The House report, though, would fully fund MSR at $949.3 million, and instructs NASA to request the funding necessary in 2025 to ensure the MSR sample retrieval lander and Earth return orbiter missions launch by 2030.

The report, though, refers to the “pending Independent Review Board’s results.” That board completed its work in September, concluding there was a “near zero probability” that MSR could stay on cost and schedule. It also concluded that the overall MSR program would cost between $8 billion and $11 billion, well above the $5.3 billion threshold mentioned in the Senate report.

The funding for MSR in the House bill has ripple effects for other NASA programs. The House bill provides $7.38 billion for NASA science programs, slightly more than the $7.341 billion in the Senate bill. However, the House bill reduces funding for Earth science, astrophysics, heliophysics and biological and physical sciences compared to the Senate bill, which had already been cut in most cases from the agency’s request.

The House report provides little direction on Earth science, astrophysics or heliophysics programs. However, the proposed cut was one reason Mark Clampin, director of NASA’s astrophysics division, said Oct. 13 he was considering cuts in operating budgets for the Chandra X-Ray Observatory and Hubble Space Telescope.

Curiously, while the House bill fully funds MSR, it would block a far smaller expenditure on another Mars program. “The recommendation does not support the requested funding for the Rosalind Franklin ExoMars rover,” the report states, a reference to proposed NASA support for that European Space Agency mission that ESA sought after terminating cooperation with Russia last year.

That support is still being negotiated but would likely include thrusters for a new landing platform for the rover, radioisotope heating units and a launch. NASA’s 2024 budget proposal did not identify specific funding for that cooperation but instead included it as part of a “Mars Future Missions” program line that also includes planning for a receiving facility for the samples brought back from the MSR line of missions. NASA requested $49.9 million for Mars Future Missions in its budget proposal.

For that receiving facility, the House report offered specific language, directing NASA “to prioritize proximity to the current curator for all NASA-held extraterrestrial samples” by placing the new facility within 30 miles (50 kilometers) of that current facility, which is located at the Johnson Space Center. NASA has yet to select a potential location for that receiving facility, but noted in the budget proposal that it must have a rating of Biosafety Level 4 and could be part of an existing government facility.

The House bill also reduces funding for space technology and space operations, but by smaller amounts than the Senate bill. The report section on space operations does not mention funding levels for the commercial low Earth orbit development, or CLD, program, which the Senate bill fully funds. It does, though, provide the $180 million NASA requested for an International Space Station deorbit vehicle.

The House bill fully funds NASA’s exploration account, which includes the Space Launch System, Orion, ground systems, and other capabilities like the Human Landing System and spacesuits.

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...