The Democratic leaders of the House Science, Space, and Technology (SS&T) Committee gave the Trump Administration’s proposal to put astronauts back on the Moon by 2024 a cool reception today. Committee chairwoman Eddie Bernice Johnson (D-TX) asked whether it was just “hot air” — rhetoric without a plan and credible cost estimates. NASA Administrator Jim Bridenstine promised a revised NASA budget request with that information in the next two weeks.

Vice President Mike Pence announced the new deadline of 2024 for returning American astronauts to the Moon last week. That would be the final year of a potential Trump second term. He told NASA to do it by “any means necessary,” and if it cannot, then it is NASA that must change, not the goal.

NASA’s notional plan, reflected in its FY2020 budget request, has been 2028. The new mandate is 4 years earlier and just 5 years from now.

Bridenstine is enthusiastic about 2024, but makes no secret that it will require resources above and beyond what it is that budget request, submitted to Congress just 3 weeks ago.

Johnson had many questions, including just how much more money it will take and whether it means cannibalizing other NASA programs.

We need to know how much—if any—money the President proposes to add to NASA’s budget over each of the next five years and the extent to which NASA’s other programs will be cannibalized or cut to fund this initiative. We need to know if our international partners will be part of it or simply frozen out, as some of the rhetoric would seem to suggest. We need to know if the International Space Station will have to be shut down within the next few years to free up funding for the lunar crash program. In short, we need specifics, not rhetoric. Because rhetoric that is not backed by a concrete plan and believable cost estimates is just hot air. And hot air may be helpful in ballooning, but it won’t get us to the Moon or Mars. — Rep. Eddie Bernice Johnson (D-TX)

Bridenstine’s written statement did not address how NASA would meet Pence’s charge. Johnson said the statement was “disappointing and inadequate” and wanted to know the justification for the “crash schedule.”

Pence’s explanation at the March 26 meeting of the National Space Council was that America is in “space race today, just as we were in the 1960s, and the stakes are even higher.” China and Russia are competitors, but “we’re also racing against our worse enemy: complacency.”

Bridenstine took another tack today. He said that speeding up a human return to the Moon would also accelerate putting humans on Mars because the Moon is the proving ground for human Mars exploration.

Sending humans to Mars in the 2030s was the goal of the Obama Administration and has been championed by many in Congress, especially on this committee, on a bipartisan basis over the past decade. Committee member Rep. Ed Perlmutter (D-CO) is famous for his “Mars in 2033” bumper sticker. Bridenstine was a member of Congress and of this committee before becoming NASA Administrator and he brought one of those bumper stickers with him to the hearing today.

Obama eschewed sending humans to the lunar surface, however. His focus was Mars. The Trump Administration restored human lunar landings to NASA’s plan, with Mars as the “horizon” goal. NASA calls it the “Moon to Mars” program.

Johnson wanted to know when Bridenstine was told that the White House was going to speed up the Moon program and whether it was before the FY2020 budget was sent to Congress. Bridenstine avoided a direct answer, saying he had had conversations with Pence about it and Pence said “he was intending to make that announcement.”

Rep. Bill Foster (D-IL) asked who made the 2024 decision. Bridenstine said it was “a decision by the President of the United States, announced by the Vice President of the United States.”

As for the cost, Bridenstine said the Administration is working on an amendment to the budget request and hopes to submit it by April 15.

April 15 is the date by which Congress is supposed to adopt each year’s Budget Resolution setting out the top-line numbers for how much money Congress can allocate for various purposes.

In her written statement, Rep. Kendra Horn (D-OK), who chairs the Space and Aeronautics Subcommittee, wondered what proposal the committee was actually considering — the budget request as submitted that has a 2028 date for astronauts landing on the Moon; Pence’s 2024 plan; a reprogramming request for the current fiscal year that NASA just submitted to Congress; or a congressionally-required report NASA submitted last Friday, a year and a half late, laying out its plans for getting humans to Mars (the National Space Exploration Campaign Report).

Republicans on the committee also wanted to know about the cost. Ranking Member Frank Lucas (R-OK), was circumspect about the 2024 date, but seemed generally pleased with the direction of NASA’s activities.

“Aside from the budgetary unknowns, we do have a robust proposal on how we can achieve lunar exploration by 2024. The proposal focuses on the development of technologies that enable future exploration rather than deadend, one-off technologies.” – Rep. Frank Lucas (R-OK)

He pressed Bridenstine on NASA commitment’s to the Space Launch System (SLS). The FY2020 budget request proposes delaying upgrades to SLS such as building the Exploration Upper Stage (EUS) that would increase SLS’s capacity. The initial version of SLS will be able to lift 70 metric tons (MT) to low Earth orbit, but the ultimate configuration is intended to almost double that to 130 MT. Bridenstine agreed that the EUS is essential and the 130 MT remains the goal, but right now the focus must be on completing the SLS core stage which is “more challenging than previously anticipated.”

Rep. Brian Babin (R-TX), Ranking Member of the Space and Aeronautics Subcommittee, said the 2024 goal is “very exciting,” but also asked about the cost. Bridenstine continued to demur, saying plans are “in flux” and reiterated that he will come back to Congress with a new estimate. He also assured Babin that the International Space Station (ISS) program will not be affected by this new goal. Babin represents Johnson Space Center, which manages the ISS program.

Overall, members of this committee historically are strong NASA supporters and enthusiastic about bold human exploration plans. Most are just as passionate about NASA’s science, aeronautics, and technology development programs, as well as its support of STEM education, however. With the exception of Earth science, bipartisanship usually prevails on NASA issues. The challenge is priority setting in a perpetually constrained budget environment. Hence the focus by both parties today on discovering the cost implications of this plan and whether it is achievable without damaging other NASA programs. The real debate cannot begin until those details have been provided.