The future of U.S. space exploration and NASA-funded science is up in the air as President-elect Donald Trump prepares to return to office.

“There’s just so many question marks,” says political scientist Victoria Samson. Where will humans go in space, and when? What will SpaceX billionaire and close presidential adviser Elon Musk’s influence be over NASA and space policy? What does the nomination of billionaire space tourist Jared Isaacman to lead NASA mean?

“If I have one thing to say, everything is unclear,” says Samson, who is in the Washington, D.C., office of the Secure World Foundation, a nonprofit space sustainability organization. “Anything could happen.”

Space scientists are making predictions based on things Trump and his allies have said in the past. Naming Isaacman as his pick to be the next NASA administrator reflects priorities for space exploration that had already been telegraphed during the election: getting boots on the ground of another world, as quickly as possible.

That other world is probably the moon. But it could be Mars, if some in Trump’s orbit get their way. And while human and commercial spaceflight will probably get a boost in the next administration, it’s less clear what the future holds for astronomy and pure space science.

Here’s what Science News will be watching in the coming years.

How (and when) will NASA return humans to the moon?

Every time there’s a change in presidential administrations, there’s a corresponding change in destination for humans in space. In the early 2000s, George W. Bush directed NASA to land astronauts on the moon again “no later than 2020.” In 2010, Barack Obama cancelled that program and aimed humans at asteroids instead (SN: 4/15/10). In 2017, Trump scrapped that plan and swung back toward the moon with the Artemis program (SN: 12/1/22).

That destination will probably remain stable through the second Trump presidency. Artemis continued under Joe Biden, and NASA currently plans to land humans on the moon in 2027 with the Artemis III mission (a slip of about three years from the original goal of 2024).

One question raised by Trump’s election is how astronauts will get there. Right now, Artemis III is supposed to launch on NASA’s long-awaited Space Launch System, or SLS. The plan is that the astronauts will rendezvous with a SpaceX Starship vehicle in orbit, which will take them to the surface of the moon.

But SLS has been off schedule and over budget for years. The first SLS flight, originally set for 2017, was in November 2022. NASA had spent $11.8 billion on developing the rocket up to that point, and would need to spend billions more per launch going forward, according to a Government Accountability Office report in 2023.

Isaacman himself has been openly critical of the program as an example of government inefficiency. The rocket is almost certainly on the chopping block.

“I think most people see SLS as a dead program walking,” says space policy expert Casey Dreier of the Planetary Society, who is based in Bellingham, Wash. “I think the question at this point is how quickly the SLS project winds down, rather than if it continues.”

There’s a chance SLS will survive long enough to launch Artemis III. The U.S. Congress could fight to keep its funding steady, and thereby keep related jobs in states with NASA centers.

And for all its problems, SLS has already flown and is all set for the second Artemis launch, scheduled for April 2026 (SN: 11/16/22). Starship has had test launches. But it hasn’t done any dockings in space or landed on the moon without people, crucial steps before Artemis III can happen.

“The big delay on Artemis III is whether Starship will be ready,” Dreier says. “That’s a very nontrivial set of problems to solve.”

Another question is whether the United States will continue its participation in the Artemis Accords, a nonbinding guidance document for activities on the moon established in 2020, during the first Trump administration. The accords state NASA’s intention to explore space peacefully and transparently, in cooperation with other nations, and to share scientific data, among other things. More than 50 countries have signed onto the accords, many of which don’t have their own space programs.

The United States is effectively saying “we want to go there, and go together,” Samson says. “It’s a question if the U.S. will continue this diplomatic outreach, which I would argue has been incredibly successful.”

Will we put boots on Mars or return samples from the Red Planet?

Through all the zigzags in NASA’s marching orders, the eventual goal was always to send humans to Mars (SN: 8/8/14). That goal may become a higher priority in the second Trump administration.

Sending humans to Mars has long been a stated goal for SpaceX, and for Musk personally. He has posted on his social media site, X, that SpaceX could send humans to Mars within the next four years. That’s not really feasible, a team of mechanical and aerospace engineers reported earlier this year in Scientific Reports. But the drive is there.

Trump talked explicitly about accelerating trips to Mars on the campaign trail. In an October rally in Pennsylvania, for example, he said, “We will land an American astronaut on Mars…. Get ready, Elon, get ready. We gotta land it, we gotta do it quickly.”

And Isaacman called out Mars in his post on X accepting the nomination for NASA administrator (an appointment that requires Senate confirmation). “Americans will walk on the Moon and Mars and in doing so, we will make life better here on Earth,” he wrote.

Meanwhile, NASA’s plan to bring Mars rocks back to Earth is on shaky ground. The agency’s Mars Sample Return program was hit hard by budget cuts in 2024 (SN: 5/8/24). In June, NASA put out a call for new ideas for returning Mars samples with private companies — including SpaceX.

“There’s a lot of different things that we’re considering,” said Lindsay Hays, a Mars scientist at NASA Headquarters, during a December 12 news briefing at a meeting of the American Geophysical Union in Washington, D.C. “We’re hoping that we’ll be able to have some new plan moving forward early next year.”

Will low Earth orbit see more satellites and launch competition?

Musk is already a big player in low Earth orbit. SpaceX has launched thousands of satellites in its Starlink project to bring wireless internet access to a broad swath of the planet. Other companies are launching their own versions. These satellite constellations threaten scientists’ ability to do astronomy and may wreak havoc on the stratosphere at the end of their lives (SN: 9/20/21, SN: 11/22/24).

The billionaire has also been tapped to help lead a new Department of Government Efficiency — an outside advisory commission that Trump has said will “dismantle government bureaucracy” and “slash excess regulations.” That, along with the fact that Musk donated at least $250 million to Trump’s reelection campaign, creates a potential conflict of interest, Eric Berger, the senior space editor at Ars Technica, has noted. “Musk is unquestionably in a position for self-dealing,” Berger wrote on November 8.

Musk has sparred with the Environmental Protection Agency over environmental impacts at SpaceX’s launch site in Texas, and with the Federal Aviation Administration over fines for safety issues and launch regulations. The current head of the FAA will resign before Trump takes office.

“There’s been frustration, at least for Elon, at what he feels to be onerous requirements by the FAA and EPA,” Samson says. She wonders if environmental impact statements and launch requirements will be loosened or eradicated in the next administration.

As for private human spaceflight, SpaceX is largely the only game in town. “SpaceX has become, frankly, the de facto monopoly of launch right now,” Dreier says.

But that monopoly might not last. Colorado-based company United Launch Alliance has launched its Vulcan heavy-lift vehicle twice. On December 10, the company Blue Origin announced its intention to fly its New Glenn heavy-lift rocket before the end of the year. And California-based company Rocket Lab aims to complete its own reuseable rocket, called Neutron, in 2025.

“We actually have a diversity of launch providers, which is very powerful,” says space business and policy expert Zaheer Ali of Arizona State University in Phoenix.

One question for the coming years is what will become of these other launch companies. If they succeed, there could be many ways to get to space, healthy competition between companies and backup options if one of them fails. But some space policy experts worry that Musk’s influence could lead to policy changes that benefit SpaceX at the expense of its competitors.

What about space science in general?

Isaacman’s nomination was met with surprise and a certain amount of relief in the astronomy community.

The billionaire’s enthusiasm for human spaceflight is obvious. In the past five years, he has funded two commercial SpaceX flights, flying as an active crew member on both. He offered to boost the Hubble Space Telescope to a higher orbit, thus extending its lifetime, on a future private spaceflight (NASA declined). And he wrote a letter to current NASA administrator Bill Nelson in April, advocating for saving the space-based Chandra X-ray Observatory from funding cuts (SN: 5/8/24).

“I do believe Isaacman is going to be a significant proponent of science and basic research,” Ali says.

But with the new Department of Government Efficiency, funding cuts are anticipated across the board, and NASA is unlikely to escape them, Dreier says. “I think what we can say for relatively certain is that NASA will be facing diminished budgets for at least the next couple of years,” he says.

With the expected increased focus on human spaceflight, those cuts will probably hit NASA science hardest, he says. At particular risk are projects studying Earth and its climate, which Trump tried to cut during his first term in office (SN: 11/25/24).

It’s not clear how NASA’s priorities in space will shake out. The last decadal survey in 2021, a document in which the astronomy community laid out its priorities for the following 10 years of missions and spacecraft, identified several space-based observatories that could replace the aging fleet of Great Observatories, including Chandra and Hubble (SN: 11/4/21). But launch costs and budget constraints already hamper those ambitions.

More commercial launches with rockets that are larger than what’s currently available could reduce the cost of each mission, and so allow more of them to fly, some astronomers argue.

“Assuming it is successful, Starship will dramatically enhance our space capabilities in ways that will qualitatively alter how astrophysics missions can be built,” astronomers Martin Elvis, Charles Lawrence and Sara Seager wrote in a 2023 essay in Physics Today.

Other astronomers are already thinking about how to make the human spaceflight focus useful for science.

“A lot of us are concerned about Artemis eating up all the science budget,” astronomer Tom Maccarone of Texas Tech University in Lubbock said at a recent meeting in Boston for astronomers who use the Chandra telescope (SN: 12/6/24). “Maybe we should think about how to use that to our advantage rather than suffering from it.”

He nodded toward proposals to build telescopes on the moon, where certain observations can be made more easily than on Earth. “There may be free rides,” he said. “If we want to do it in the 2050s, we should start thinking seriously about it now.”

But, Ali says, which research projects get to hitch those rides might not be decided by NASA, and might not favor pure science. He anticipates that NASA mission leaders may be asked to justify to Congress how their projects will contribute to other national priorities, aside from great science.

Staff writer Nikk Ogasa contributed to this story.