COLORADO SPRINGS — NASA’s effort to return samples from Mars could require $250 million more than currently planned over the next two years, putting more pressure on the agency’s overall science portfolio.

Testifying before the Senate Appropriations Committee’s commerce, justice and science subcommittee April 18, NASA Administrator Bill Nelson said he had recently been informed that the Mars Sample Return (MSR) program would need $250 million more in the current 2023 fiscal year and 2024 to stay on track.

“I was just out there,” Nelson said, referring to a recent visit to the Jet Propulsion Lab, the lead center for MSR, “and they’re saying they want an additional $250 million in this year — meaning in this year, existing, 2023 — and 2024.”

He did not discuss the specific issues that prompted the need for additional money. MSR received $822.3 million in the fiscal year 2023 omnibus spending bill and the agency requested $949.3 million in its fiscal year 2024 budget proposal, but warned in that document that costs for the program could grow beyond 2024.

Any additional money for MSR in 2023 would require reprogramming money from elsewhere in the agency, a process that requires congressional approval through an operating plan. NASA has not yet published an operating plan for fiscal year 2023.

Nelson was responding to a question from the subcommittee’s chair, Sen. Jeanne Shaheen (D-N.H.), who was concerned about the effects MSR was having on other parts of NASA’s science budget. In its 2024 budget proposal, NASA said it was delaying work on a heliophysics mission, the Geospace Dynamics Constellation (GDC), and slowing work on technology development for a future astrophysics flagship mission, the Habitable Worlds Observatory, because of cost growth in MSR.

“Some of those costs are not going to be avoided, and we’re going to have to make choices,” Nelson said, suggesting that MSR itself might be delayed. “You can get it done, but it may not be done right on the time we’re hoping it would be done. If you stretch it out over a longer period of time, you can get the problem done.”

NASA is gearing up for a second independent review of MSR. NASA announced April 13 it selected Orlando Figueroa, a former NASA official who once led NASA’s Mars exploration program, as chair of the independent review board that will convene this summer to review the status of MSR before a confirmation review this fall that will set formal cost and schedule targets for the program.

Jeff Gramling, MSR director at NASA Headquarters, said at an April 12 meeting of the Mars Exploration Program Analysis Group that the independent committee would likely work for six to eight weeks in the summer, just before the overall MSR preliminary design review.

As at other recent events, Gramling declined to estimate the cost of MSR, noting the upcoming confirmation review. He made no mention of any additional near-term funding needed for the program.

The budget pressures on NASA’s science budget could extend to another mission, the Dragonfly spacecraft in development to go to Saturn’s moon Titan. Sen. Chris Van Hollen (D-Md.) said he was worried about Dragonfly after the 2024 budget request offered $327.7 for the mission, compared to $400.1 million it received in 2023. NASA’s 2023 budget proposal projected spending $317.8 million on Dragonfly in 2024.

Van Hollen interpreted the 2024 request as a cut to Dragonfly that could delay its launch, even though NASA says it remains on schedule. “Everything I know from the experts is that it doesn’t compute. You can’t cut by 20% and still remain on target,” he said. He added he was “troubled” by the state of MSR even as Dragonfly passed its recent preliminary design review.

Nelson said that Dragonfly remained on schedule for a 2027 launch and that the agency would have a better understanding of progress on that mission later this year. However, he stated several times that, despite a record budget of $8.26 billion for science proposed for the agency, tough decisions about missions were necessary. “In the largest science budget ever, you can’t fit 10 pounds of potatoes in a five-pound sack,” he said.

Speaking at the 38th Space Symposium April 18, Nicola Fox, the agency’s new associate administrator for science, also acknowledged budget pressures. As the former director of NASA’s heliophysics division, she acknowledged delaying GDC was particularly difficult. “But it’s the right thing to do,” she said, because it is still in its early phases of development.

Fox, who became associate administrator in late February, said the rollout of the fiscal year 2024 budget proposal made her acquainted quickly with the budget issues in the overall science portfolio. “I got a question the other day, ‘What are you doing to familiarize yourself with challenges?’ Well, I got the budget.”

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...