“It’s a 180-degree shift from no moon to moon first,” said John Logsdon, a space-policy expert and former director of the Space-Policy Institute at George Washington University.

The announcement is obviously good news for space-transportation companies and lunar researchers lamenting the country’s 45-year absence from the moon. For those in the Mars camp, many of whom aim for a human mission to the planet by 2033, the news puts their ambitions on shakier ground.

The administration’s push for a return to the moon may be unambiguous now, but plenty of questions remain, ranging from the basic, like when and how, to the intriguing, like the role commercial spaceflight companies might play. NASA also wouldn’t be starting from scratch. The space agency has spent the last decade building the Space-Launch System and Orion, a rocket and spacecraft intended to carry people into deep space but also to build a cislunar way station called the Deep-Space Gateway. NASA planned to use the Deep-Space Gateway as a place for astronauts to prep for deep-space journeys, but the new shift could see the station being used for lunar landings.

Both time-tested contractors and growing commercial companies will be eager to work on potential lunar activities. Boeing is currently developing a capsule that would ferry people into low-Earth orbit, and SpaceX said its proposed mega-rocket, which is mostly intended to fulfill Elon Musk’s Sim City-esque ambitions for Mars, could contribute to travel to the moon. Musk, well aware of the political benefits of it, leaned heavily into lunar ambitions. “It’s 2017. We should have a lunar base by now,” he said recently. “What the hell’s going on?”

Federal support for moon research is also good news for lunar scientists like Paul Spudis, a scientist at the Lunar and Planetary Institute in Houston who writes frequently in support of a return. He dismissed NASA’s Mars ambitions as unrealistic and a public-relations stunt. “I see the vice president’s remarks not so much as a pivot in policy as a belated recognition of simple reality,” Spudis wrote in an email. “They don't have have an architecture, they don't have the spacecraft, they don't have the technology, and most assuredly, they don't have the money to bludgeon any difficulties into submission.”

Mars proponents, naturally, disagree. “We weren’t anywhere close to being ready” to going to Mars, Logsdon said, but to dismiss the objective as simply publicity is wrong. NASA has invested over the years in some research for the requirements of a mission, including life-support systems and landing technology, he said.

“Most of the people who are Mars-centered worry that we’ll get stuck on the moon, all the resources available will be focused on lunar exploration, and the idea of getting to Mars will slip indefinitely into the future,” Logsdon said.