If approved by Congress, the White House's budget proposal would prompt NASA to reimagine its moon program. David Ariosto looks at the legal strategy, the architecture options and their tradeoffs.
The plan set down by the first Trump administration was clear: Send American astronauts back to the moon as preparation for future crewed missions to Mars, leveraging legacy hardware as much as possible to reduce development times. Under this Artemis program, NASA’s Space Launch System rockets would loft crews in their Orion capsules toward lunar orbit, where Orions would rendezvous directly with commercial landers for those initial landings. By 2030, officials envisioned positioning the Lunar Gateway space station near lunar orbit to serve as a staging point for long-duration surface stays and, someday, trips to more distant destinations.
But even before President Donald Trump’s second term commenced in January, questions abounded as to whether, and how, this strategy might shift. Part of the answer came last week, in the topline fiscal 2026 budget proposal released by the White House’s Office of Management and Budget. In addition to reducing NASA’s overall budget by nearly 25%, the administration proposes terminating Gateway and phasing out SLS and Orion after the Artemis III landing — the first crewed moon mission since Apollo 17 in 1972.
“The Budget refocuses NASA on beating China back to the Moon and putting the first human on Mars,” the document reads, with a net increase of $647 million for “human space exploration” initiatives to the moon and Mars.
If approved by Congress, this would prompt a dramatic shift in NASA priorities and the broader architecture of U.S. space policy but would stop short of the full pivot toward Mars advocated for by Elon Musk, SpaceX CEO and top Trump adviser.
The reason might be rooted in pragmatism: While a president can adjust direction within the boundaries of the law, the executive branch cannot legally override or ignore laws without congressional action. And in this case, Congress was explicit. A 2018 addition to Title 51 of the U.S. Code directs NASA to “establish a program to develop a sustained human presence in cis-lunar space or on the moon” as “a stepping-stone to future exploration of Mars and other destinations.” SLS and Orion are mentioned by name in subsequent passages, meaning NASA’s “current legal imperative” is to incorporate the hardware into any crewed lunar exploration plans, explains Michelle Hanlon, executive director of the Center for Air and Space Law at the University of Mississippi.
“Chances are the president’s legal team is taking the position [that] extending SLS through Artemis III” satisfies that requirement, adds Michael Listner, founder and principal of the Space Law and Policy Solutions consultancy in New Hampshire — and, in his view, it “very well could.”
Here again, pragmatism might have factored in, given that the hardware for these early flights is well underway, particularly that for the Artemis II crewed loop around the moon that is scheduled for early 2026. Lockheed Martin this week delivered the Orion capsule to NASA’s Kennedy Space Center in Florida, where technicians are in the midst of stacking the SLS rocket.
By that logic, SLS and Orion might also be the best chance of keeping the Artemis III landing on target for 2027 — but not everyone is so sure that Congress will stick to that plan.
“That law can be amended with the flick of a pen,” says Doug Loverro, a former NASA official who led Artemis and the agency’s other human spaceflight programs for several months during the first Trump administration.
Any “flick” would still have to come from Congress, yet even here there could be a degree of uncertainty, in Hanlon’s view. She notes that Congress that has already granted the White House more control than usual over this fiscal year’s federal spending.
For now, however, there appears little congressional appetite for a dramatic shift to Artemis, based on the nomination hearing of Jared Isaacman, Trump’s pick for NASA administrator. In his opening remarks and questions to Isaacman, Sen. Ted Cruz (R-Texas), repeatedly emphasized that substantial changes in policy or architecture could undermine U.S. space leadership amid the intensifying competition with China.
“An extreme shift in priorities at this stage would almost certainly mean a red moon — ceding ground to China for generations to come,” he said during that April 9 hearing, a reference to China’s goal of landing its own taikonauts on the moon by 2030.
Orion and the Gateway program are overseen by NASA’s Johnson Space Center, located in Cruz’s home state. And historically, lawmakers of both parties have been pugnacious advocates of legacy programs that bring jobs, funding and economic output to their districts.
Also notable in last week’s proposal was the administration’s suggestion of what should succeed SLS and Orion: “more cost effective commercial systems that would support more ambitious subsequent lunar missions.”
What might those be? No specific hardware was named, but SpaceX’s behemoth Starship-Super Heavy is the only such vehicle in development that would be capable of transporting crew and large amounts of cargo to the moon and beyond. A Starship upper stage has yet to reach orbit, but SpaceX has nearly $4 billion in NASA contracts to provide Starship lunar landers for the Artemis III and Artemis IV landings. If SLS were canceled, Starship could be an attractive alternative because it could serve as a launcher, lander and return vehicle all in one.
Of course, this architecture would require greater dependence on SpaceX and hinge almost entirely on Starship’s success. If more redundancy was desired, another option would be to launch astronauts separately aboard a modified heavy-lift rocket, such as a Blue Origin New Glenn or United Launch Alliance Vulcan Centaur, and launch their lander aboard a separate rocket.
But there’s an additional wrinkle: In this scenario, astronauts would still require a capsule that could withstand the rigors of launch and reentry.
That is not likely a quick fix. After nearly two years of analyzing the heat shield cracking and erosion that an unoccupied Orion experienced as it plunged through the atmosphere at the end of the 2022 Artemis I test flight, engineers determined that had astronauts been aboard, they would have been safe. Still, NASA opted to change the reentry trajectory for Artemis II to avoid excessive accumulation of heat while also making substantive upgrades to the shield.
Despite these uncertainties, Loverro points out that Orion remains the United States’ only lunar-rated capsule. Starship or a SpaceX Crew Dragon capsule could be upgraded, but he estimates that it could take up to eight years to make the modifications required to ensure the vehicles could withstand the deep space environment and reentry conditions — well past Orion’s notional final flight in 2027.
Such a gap would be reminiscent of the one left in 2011 by the retirement of the space shuttles, he adds. It was nine years before Crew Dragon was developed and received NASA’s approval to ferry astronauts to and from the International Space Station. In the interim, NASA had to pay for seats aboard Russian Soyuz capsules.
“We should learn from that miscalculation,” Loverro says. “We need to keep Orion around until either Dragon or Starship is ready.”
Opener photo: An illustration of an Artemis lunar surface mission.
