As far as legislative moments go, the passage of a minor amendment to an innocuous US House resolution on Wednesday was not exactly groundbreaking. But for space exploration enthusiasts, the amendment offered by US Rep. Kevin Mullin, D-Calif., was kind of a big deal.

That's because, for the first time since the 1970s, the idea of space-based solar power has been addressed legislatively by the US Congress.

"Although the technology to gather solar energy in space and send it to the surface as electricity is not yet commercially viable at scale, we already know from early research that it is possible," Mullin said during a meeting of the Science, Space, and Technology Committee on Wednesday.

Mullin was seeking to amend House Resolution 2988, a bill instructing NASA and the US Department of Energy to collaborate on key areas of research and development, including propulsion, artificial intelligence, astrophysics, Earth science, and quantum computing. He sought to add space-based solar power to the list. The amendment passed overwhelmingly by a bipartisan committee vote.

In his remarks, Mullin noted that Europe, Japan, China, and the United Kingdom are all studying the technology and considering in-space demonstrations. And in the United States, the California Institute of Technology recently demonstrated the ability to wirelessly transmit power in space and beam detectable power back to Earth.

"A lot of the technology that once made this source of energy the work of science fiction is now much cheaper, and easier to deploy than ever, putting it within reach," Mullin said. "But it's not inevitable that this promising research will become feasible at scale. There are still science and engineering hurdles to overcome. And if the United States doesn't do it, we know our friends and global competitors will."

Sending a message

The legislation, with Mullin's amendment now attached, should be voted on by the committee on Thursday. If passed, as expected, it will likely become part of a House authorization bill later this year.

The House resolution carries no funding for these initiatives, and it's not like NASA and the Department of Energy will drop everything tomorrow and start working on space-based solar power. But the resolution signals the intent of Congress to NASA and the Department of Energy that it is interested in seeing some movement on this topic. This could presage eventual funding.

Before its passage, the amendment was supported by several space advocacy groups, including the Alliance for Space Development, Space Frontier Foundation, and National Space Society. "This is the first time since the 1970s that the idea of space solar power has been addressed in legislation," said Jonathan Dagle, a policy manager for the National Space Society. He characterized the amendment as "a small but significant victory."

NASA could do with a little prodding on the subject. Last year, at the International Space Development Conference, a NASA official said the agency had begun a short-term study evaluating the prospects of space-based solar power. This was the agency's first real look at the subject in about two decades. However, that study has not been released publicly, as there were apparently some policy concerns about the first draft. The revised study may finally be released in late June or July.

Part of the renewed interest in solar power from space is due to the expansion of launch capabilities, particularly the potential of SpaceX's Starship launch vehicle to carry large payloads into orbit with a reusable first and second stage. This dramatic improvement in launch costs and upmass could help to address some of the economic concerns with the technology—namely that it is often more efficient to put solar panels in the desert than in space.