On Tuesday, budget writers in the US House will make changes to a bill that funds federal commerce, justice, and science agencies—which includes NASA—for the coming fiscal year. But a draft of the full bill released Monday contains a blockbuster for the space agency: the House calls for a pivot away from NASA’s direct-to-Mars vision toward a pathway that includes lunar landings first.

Since a space policy speech in 2010 by President Obama, the space agency has been following a loosely defined plan to first send astronauts to visit a fragment of an asteroid near the Moon and then conduct other operations in the vicinity of the Moon before striking off for Mars some time in the 2030s. However a number of independent reports, such as the National Research Council’s Pathways to Exploration, have questioned the viability and sustainability of a direct-to-Mars plan. That panel called for NASA and the White House to reconsider the Moon as an interim destination.

In the new House budget, which provides funding for fiscal year 2017, the committee recognizes there are some useful components of the asteroid mission. These include propulsion research and asteroid deflection, but committee members found that “neither a robotic nor a crewed mission to an asteroid appreciably contribute to the overarching mission to Mars.” The costs of such a mission are also unknown, the committee wrote.

“Toward that end, no funds are included in this bill for NASA to continue planning efforts to conduct either robotic or crewed missions to an asteroid,” the bill states. “Instead, NASA is encouraged to develop plans to return to the Moon to test capabilities that will be needed for Mars, including habitation modules, lunar prospecting, and landing and ascent vehicles.”

The bill must still be approved by the full Appropriations Committee and House and then squared with Senate legislation, which does not explicitly call for lunar landings and exploration as a precursor to Mars missions. However the proposed law lays down a clear marker for the next president—Republican or Democrat—when the new administration considers space policy.

Turning away from the Moon

Even before President Obama came into office, there was general agreement in the US space community that NASA should establish Mars as the agency’s horizon exploration goal. Under President George W. Bush, however, the space agency’s plans called for returning to the Moon first. This would allow NASA and its astronauts to learn how to live on an airless world without protection from the Sun’s radiation and develop technologies such as lunar ice mining that could be applied to missions deeper into the Solar System, such as Mars.

Obama eschewed this plan, however. As Buzz Aldrin looked on during a 2010 space policy speech, Obama said of the Moon, “I just have to say pretty bluntly here, we’ve been there before. Buzz has been there before.”

Since the 2010 speech, NASA has pushed to meet the president’s new goals. But the agency has yet to outline a clear roadmap for how to do this, nor has it said how much Mars will cost.

Critics have said an agency with no plan is going nowhere, and others contend it hasn’t presented Congress with a budget because it doesn’t want to give legislators “sticker shock.” NASA’s focus on a “Journey to Mars,” even when the resources do not exist to pull it off, has been an increasing source of frustration within the aerospace community.

Back to the Moon

Just last week, former astronaut Leroy Chiao and Space Foundation CEO Elliot Pulham gave voice to some of these frustrations. Writing about the desire to explore Mars, they said “It is the primary longer-term goal of space exploration. But since it requires far more funding than is available, and despite all the fanfare surrounding it, the US still has no formal Mars program.”

In their op-ed for The Mark News, Chiao and Pulham argued for a return to the Moon—and not simply because it is more affordable. Most of NASA’s international partners, including the European Space Agency, have expressed a preference for lunar exploration. As NASA flies around the Moon in cislunar space, Chiao and Pulham warned, these countries may partner with China, which has said it intends to send humans to Earth’s satellite within a couple of decades.

Additionally, the burgeoning US commercial space sector has also pushed for lunar exploration. Congress passed the Commercial Space Launch Competitiveness Act at the end of 2015, which allowed private companies to keep any resources they mined from asteroids or, critically, the Moon. A number of businesses are interested in harvesting ice believed to be abundant in dark craters at the lunar poles. In turn they would sell this to NASA or other customers as rocket fuel. But without NASA as a potential customer—and helping to develop some key technologies—these companies would have difficulty closing a business case.

A senior source in the US House who helped draft the bill confirmed to Ars that the legislation intends to put NASA back on the Moon first, then on a pathway to Mars. This is a “common sense” approach, the source said, because it works with international partners, represents a sustainable exploration plan, and leverages the private US space industry.

The new law does not force a complete rewrite to NASA's human spaceflight program. Although the House proposal will be opposed by NASA's administrator, Charles Bolden, who has spent much of his tenure talking up the "Journey to Mars," he is likely to leave the agency once President Obama's term ends. There are other senior leaders at the agency who favor going back to the Moon first. The spacecraft and rockets NASA is developing, Orion and the Space Launch System, could easily be adapted to lunar missions.