Frustrated lawmakers on the House Science, Space and Technology Committee may force a public debate on U.S. human spaceflight plans as they prepare a new authorization bill for NASA this summer. Their efforts may actually bring an important discussion about what the U.S. is doing in civil space out of closed government meeting rooms and into the view of taxpayers, who ultimately will fund it. At issue, as stated with unusual clarity by science-panel leaders in a May 21 hearing, is the best way to send humans to Mars.

Members of both parties were lukewarm at best in their assessment of the space agency's new plan to capture a small asteroid and divert it into lunar orbit for astronauts to study from an Orion capsule. Rep. Steve Palazzo (R-Miss.), chairman of the House Science space subcommittee, said he worries the asteroid-capture plan is “a detour” on the way to Mars. Rep. Donna Edwards of Maryland, ranking Democrat on the space panel, warns that “before we look at interim steps, we need first to understand what it takes to get to Mars.”

“As our space program prepares for the next step to Mars, Congress must ensure that there is a strategic plan in place,” says Rep. Lamar Smith (R-Texas), chairman of the full committee.

Smith notes Congress has repeatedly endorsed using the lunar surface as a “training ground” for human missions to Mars, as with this concept (shown above) of inflatable habitats proposed by Bigelow Aerospace, and he cast the hearing as an investigation into how capturing an asteroid would play the same role.

“Without a consensus for the original plan, NASA haphazardly created a new asteroid-retrieval mission,” Smith says. “Unfortunately, NASA did not seek the advice of its own Small Bodies Assessment Group before presenting the mission to Congress. If NASA had sought the advisory group's advice, they would have heard it was 'entertaining, but not a serious proposal.' Maybe that's why they didn't ask.”

If the reauthorization process for NASA actually produces the debate Smith wants, it will reheat a fundamental disagreement simmering since the then-new Obama administration killed the Bush-era Constellation program of post-shuttle human space exploration. Under that approach, a lunar landing in the 2020s would provide the experience needed to move on to the red planet.

But a renewed debate also may find common ground that eluded both sides in President Barack Obama's first term. While witnesses at the hearing disagreed on the Moon-vs.-asteroid issue, they accept Obama's view—endorsed by the requisite blue-ribbon commission—that there wasn't enough funding for a Constellation-level assault on Mars.

“All of us agree, I believe, on the next step—orbit the Moon,” says Cornell University astronomer Steven Squyres, chairman of NASA's Advisory Council and top scientist on the twin Mars Exploration Rovers. “Beyond that, my plea to you, my heartfelt plea, please do not mandate another step for NASA beyond lunar orbit unless there is ample funding for it. That would amount to an unfunded mandate, and that is the bane of government agencies.”

Louis Friedman, the former Planetary Society chief who co-chaired the Keck Institute panel that originally drafted the asteroid-capture proposal, argued that it “creates a first step beyond the Moon, the only one which we are now capable of performing, and the only one we can afford within the current space program budget.”

But Paul Spudis, the senior staff scientist at the Lunar and Planetary Institute, argued for a series of “incremental building blocks” all the way to Mars, beginning on the surface of the Moon. Aside from its scientific and training value, he says, water and other lunar resources can “break the logistical chains” that would otherwise tie deep-space human explorers to Earth.

“The gold is at the poles and it's in the form of water, which is the most useful commodity you can have to create capability in spaceflight,” he says.

NASA essentially dropped its historic decision to end the Constellation program like a bomb, offering little justification for its plan to support developing commercial U.S. cargo and crew vehicles to reach low Earth orbit instead. That triggered an often-acrimonious debate leading to the “compromise” policy of today, with NASA continuing the Orion crew capsule begun under Constellation, and developing the heavy-lift Space Launch System, while contributing development funds on three commercial crew vehicles.

Doug Cooke, a former NASA associate administrator with long experience in human spaceflight, joined Smith in criticizing the agency for the way it handled the decision to pursue asteroid-capture, and in urging a more open approach to policymaking.

“I think that a healthy process gets inputs from your stakeholders in terms of your objectives and long-term goals, and that helps you define what missions are,” Cooke says. “I don't see that that's happened here.”