With its Artemis program, NASA aims to return humans to the moon for the first time in more than 50 years. And on the eve of a new presidential administration, agency officials have announced both a delay to the program’s next major mission and their intent to make that mission more ambitious in scope.
At a press conference last week at NASA headquarters in Washington, D.C., agency leadership announced that lingering hardware issues have forced NASA to push back Artemis II—a four-person crewed flight in an Orion spacecraft around the moon and back to Earth—from September 2025 to April 2026.
Most observers had already considered a 2025 launch unlikely. That Orion craft’s ride into space—NASA’s Space Launch System (SLS) rocket—isn’t fully assembled at the agency’s Kennedy Space Center in Florida. That places it behind the pace set by its predecessor, the uncrewed Artemis I mission. Artemis I launched in November 2022, after its SLS had been fully assembled about a year in advance.
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“The safety of our astronauts is always first in our decisions; it is our North Star,” said NASA administrator Bill Nelson in a press conference at the agency’s headquarters. “We do not fly until we are ready. We do not fly until we are confident that we have made the flight as safe as possible for the humans onboard. We need to do this next test flight, and we need to do it right—and that’s how the Artemis campaign proceeds.”
That said, agency officials are also thinking bigger about the program’s planned missions.
As originally conceived, Artemis II was a 2020s version of the 1968 mission Apollo 8, a no-frills journey around the moon and back to Earth to prove out NASA’s ability to send people safely to and from the lunar vicinity. But now that development of SpaceX’s Starship rocket is progressing rapidly, NASA officials are considering increasing the scope of Artemis II. Starship is intended to land NASA astronauts on the moon’s surface during the subsequent Artemis III mission, making the private rocket a crucial pillar of the public space agency’s ambitious plans for crewed lunar return.
NASA is now exploring the possibility of launching a Starship in parallel with Artemis II, with an eye toward possibly rehearsing the sorts of maneuvers that will need to be performed between Starship and Orion during Artemis III, which would be the first crewed moon landing attempt since 1972.
“We always want to look for ways to exploit new technology [and] new capabilities that, even five years ago, seemed like they were a bit out of reach,” said Reid Wiseman, Artemis II’s commander, at last week’s press conference. “You’re going to ask an astronaut to do more on their mission? Bring it on.”
Feeling the Heat
The delay of Artemis II stems from lingering hardware issues with the mission’s Orion spacecraft, the home away from home for its four astronauts. The big-ticket item: an investigation into the main material of Orion’s heat shield, an epoxy resin called Avcoat that misbehaved during Artemis I.
“What struck me the most was the level of detail that they provided. These are very complicated missions and very complicated technologies, and you don’t often get down into the nuts and bolts of why things are not working,” says Iain Boyd, an aerospace engineering professor at the University of Colorado Boulder, who models spacecraft thermal protection systems. “Certainly, part of it is messaging to Congress and other stakeholders across the enterprise—to convey that they know what they’re doing.”
Avcoat is extremely well characterized: it played a key role in the heat shields used during the Apollo program and underwent major testing ahead of its use in Artemis. Samples of Orion’s heat-shield materials went through more than 1,000 ground tests, the overall design went through many supercomputer simulations, and a test version of Orion successfully flew to space in December 2014. Even so, at the press conference, agency officials said that the material still contained surprises.
Although slated to launch no earlier than April 2026, engineers and technicians are already stacking the solid rocket boosters for NASA’s Artemis II crewed lunar mission.
During Artemis I’s reentry, Orion screamed through Earth’s atmosphere at a blistering speed of nearly 25,000 miles per hour (40,000 kilometers per hour), subjecting the heat shield to temperatures approaching 5,000 degrees Fahrenheit. The heat shield did its job, keeping conditions clement inside the spacecraft, but unpleasant surprises still arose in those hellish conditions. Postflight inspections revealed more than 100 places on that Orion craft’s heat shield where material wore away differently than expected, in some cases leaving pits roughly as wide as baseballs on the shield’s surface.
At the briefing, NASA deputy administrator Pam Melroy announced that this pitting stemmed in part from the Artemis I flight plan, which included what’s known as a skip reentry, in which Orion dipped into and out of the upper atmosphere to help slow its descent. This flight plan caused gas-generating thermal energy to accumulate within the heat shield’s outer layer. Extensive testing revealed that the Avcoat across the Artemis I Orion’s heat shield was unevenly permeable to gas outflows—and that, in areas that were less permeable, gases built up to the point of cracking the material.
In response, the agency is modifying future Orions’ reentry trajectories to lessen the heating that caused the gas buildup. Future heat shields, NASA officials said, will be built with Avcoat of the proper permeability.
“Just because our bottom-line temperatures were within four factors of safety, just because our guidance was right down the middle, just because we had the right amount of virgin Avcoat material left, it is tempting to believe that that means the spacecraft … performed with margin,” added Amit Kshatriya, deputy associate administrator for NASA’s Moon to Mars Program. “But everything we’ve learned in our history tells us that that’s not what ‘margin’ means.”
A Path Forward and a Changing of the Guard
The Avcoat investigation—and the messaging around its technical excellence—also represents a swan song for the Biden administration’s NASA leadership. Nelson, a former U.S. congressional representative and a former U.S. senator from Florida, announced previously that he would be leaving the agency at the end of the year. The day before the press conference, President-elect Donald Trump announced that he would nominate billionaire technology CEO and philanthropist Jared Isaacman to lead NASA. Isaacman has commanded two private SpaceX orbital missions: Inspiration4, back in 2021, and Polaris Dawn.
Isaacman’s extensive ties to SpaceX’s human spaceflight program could portend major shifts to Artemis—which is still contending with delays on key hardware. For example, to accommodate planned upgrades to the SLS for Artemis missions now slated for the late 2020s, NASA needs a new mobile launch tower. In 2019 the agency estimated that the project would cost less than half a billion dollars and would be done in 2023. It will now be delivered in September 2027 at a total cost of $1.8 billion, according to an August report by NASA’s Office of Inspector General.
The pieces of what is now Artemis have dealt with delays for years; the SLS was originally supposed to fly in late 2016. And with the latest delay of Artemis II, roughly three and a half years will have elapsed between Artemis’s first two major launches. That’s a far cry from the roughly annual cadence that NASA hopes to achieve with the program by the early 2030s.
That said, the SLS and Orion have long enjoyed strong support from Congress—a key reason why Artemis is the only U.S. moon program since Apollo to have survived largely intact across two presidential administrations. If Isaacman intends to revamp Artemis by minimizing or entirely removing these costly components, he may well face hostile questions and stiff opposition from the powers that be during his Senate confirmation hearing next year—and into his notional tenure as NASA’s latest leader.
“We are handing to the new administration a safe and reliable way forward for us: which is to go back to the moon, to get there before China, to have presence in cislunar [space] … and to be on the way [from the] moon to Mars,” Nelson said at the press conference. “I think we’ve got that wrapped up with a bow.”
