Updated 6:25 p.m. Eastern with NASA comment.

WASHINGTON — President Donald Trump disrupted months of civil space policy development in a single tweet June 7, suggesting that NASA should not return humans to the Moon.

“For all of the money we are spending, NASA should NOT be talking about going to the Moon – We did that 50 years ago,” he wrote. “They should be focused on the much bigger things we are doing, including Mars (of which the Moon is a part), Defense and Science!”

For all of the money we are spending, NASA should NOT be talking about going to the Moon – We did that 50 years ago. They should be focused on the much bigger things we are doing, including Mars (of which the Moon is a part), Defense and Science! — Donald J. Trump (@realDonaldTrump) June 7, 2019

Trump’s tweet came shortly after a segment on the television network Fox Business where Jeff DeWit, NASA’s chief financial officer, was interviewed by host Neil Cavuto shortly after the agency rolled out its low Earth orbit commercialization plans. That included a discussion of the policy, announced by Vice President Mike Pence in March, to land humans on the moon within five years.

Actually, Trump's "Mars (of which the Moon is a part)" line is probably referring to the NASA flack's point that going to the moon would help us get to Mars later on. pic.twitter.com/z4wmL6ZKmb — Matthew Gertz (@MattGertz) June 7, 2019

“I thought we would advance beyond that,” Cavuto says. “I thought either we would target Mars or… Why this? Why now?” The comment was first noted by Media Matters for America, a media watchdog group.

“What we’re doing now is enabling a sustainable presence on the lunar surface,” DeWit responded. “We still need to drive that innovation and complete those technologies that will allow us to have a sustained presence on Mars.”

It also came a day after CNN published an interview with Apollo 11 astronaut Michael Collins, who has previously argued that NASA should go to Mars rather than return to the moon. Collins, in that interview, was critical of Trump. “I don’t think he’s too much aware of Mars,” Collins said. “Maybe he doesn’t understand that there is a planet Mars.”

Regardless of the source, Trump’s tweet took the space community by surprise. There was no indication prior to that tweet that the White House was reconsidering the goal of returning humans to the moon by 2024, or at all. A human lunar return has been national policy since President Trump signed Space Policy Directive 1 in December 2017.

“Japan will join our mission to send U.S. astronauts to space. We’ll be going to the moon,” Trump said at a joint press conference with Japanese Prime Minister Shinzo Abe May 27. We’ll be going to Mars very soon. It’s very exciting.

A White House official, speaking on background, argued that Mars has always been the long-term goal of the administration. “We have asked Congress for additional resources to get to the Moon by 2024, which will enable us to get to Mars roughly a decade after creating a sustainable presence on the lunar surface,” the official said.

“As @POTUS said, @NASA is using the Moon to send humans to Mars!” tweeted NASA Administrator Jim Bridenstine four hours after the president’s tweet. Bridenstine emphasize the robotic exploration of Mars that is ongoing, as well as the upcoming Mars 2020 mission.

As @POTUS said, @NASA is using the Moon to send humans to Mars! Right now, @MarsCuriosity and @NASAInSight are on Mars and will soon be joined by the Mars 2020 rover and the Mars helicopter. pic.twitter.com/Br1sTYfNzd — Jim Bridenstine (@JimBridenstine) June 7, 2019

Earlier in the day, Bridenstine spoke at the National Space Society’s International Space Development Conference in Arlington, Virginia, where he reiterated the agency was working to land humans on the moon by 2024.

In his speech, he emphasized that the technical risk of human lunar missions wasn’t the biggest challenge facing the agency. “The reason we’re not on the moon right now has nothing to do with technical risk. It has nothing to do with technology,” he said. “Technically, this is doable. The reason we’re not on the moon right now is the political risk.”

“What we have to do is, we have to not just retire the technical risk, we have to retire the political risk,” he said. “How do we retire the political risk? We go faster. We accelerate the program. The longer it drags out, the more risk there is we’re going to get diverted into something else.”