Citing "crew safety" as the agency's chief priority, NASA officials outlined a new schedule for the Artemis lunar program on Tuesday. The roughly one-year delay for each of the next three missions came as little surprise, given the significant amount of work left to be done before astronauts can return to the Moon later this decade.

"Safety is our top priority," NASA Administrator Bill Nelson said during a teleconference with reporters.

The new dates, according to NASA Associate Administrator Jim Free, are:

• September 2025: Artemis II crew flight around the Moon and back in a free-return trajectory
• September 2026: Artemis III crewed lunar landing, with two astronauts going down to the surface in SpaceX's Starship lander
• September 2028: Artemis IV crewed mission, first flight using upgraded version of Space Launch System rocket, lunar landing in Starship.

"We must be realistic," Free said. "We're looking at our Starship progress, and need for propellant transfer, the need for numerous landings. We're looking at our spacesuits that we're acquiring in a different manner than we've done before, and developing the new spacesuits as well. It's an incredibly large challenge and a really big deal."

Artemis II delays

After a successful flight of the Artemis I mission at the end of 2022—this was the debut flight of the Space Launch System rocket and an uncrewed Orion spacecraft—NASA set a goal of flying its first crewed flight inside Orion by November 2024. But that is no longer tenable while the space agency works on several issues related to the Orion vehicle, Free and other officials said.

Amit Kshatriya, a NASA engineer who oversees the "Moon to Mars" program, identified three major areas being worked ahead of Artemis II.

One of the issues has previously been discussed by the space agency. During Orion's return through the atmosphere in Artemis I, some pieces of the charred heat shield were unexpectedly "liberated." The heat shield has plenty of margin, but NASA has studied this extensively because it doesn't want a piece of the heat shield slamming into the spacecraft and damaging it. Kshatriya said NASA spent 2023 assessing the problem from many angles and expects to identify a root cause this spring.

A second area involves the abort system used by Orion to pull away from the Space Launch System rocket in case of an emergency during launch. There is some concern that while Orion has been qualified to survive this environment, some of its batteries might be damaged. Kshatriya said the agency has multiple options to address the issue.

Finally, when it took delivery of components for the Orion to be used in Artemis III, NASA found that there were failures in some of the motor valve circuitry that drives the action of valves within the spacecraft. This led to the discovery of a design flaw in the circuit. Among the components affected in Orion is the carbon dioxide "scrubber." This necessitated opening up Orion and going in and replacing these components from the Orion to be used for Artemis II. This work is currently the pacing issue for the September 2025 launch date, he said.

Artemis III delays

In terms of complexity, the lunar landing represents a significant step up in complexity. While the SLS rocket and Orion spacecraft will be thoroughly tested in Artemis II, the landing mission will add the Starship lunar lander, new spacesuits, and the rendezvous and docking of Orion and Starship in lunar orbit. All of this, Kshatriya said, represents a "significant coordination challenge."

Chief among the agency's concerns is the development of Starship. SpaceX must not only demonstrate the capability to fly the vehicle safely, the company must master the ability to transfer and store cryogenic fuel in orbit, so that a Starship can launch into orbit, be refueled, and then fly out to lunar orbit to rendezvous with Orion.

Before the Artemis III mission, SpaceX will likely fly dozens of Starship test flights; the campaign to fuel a Starship in orbit alone will take about 10 tanker flights, said Jessica Jensen, a senior engineer at the company. SpaceX must also demonstrate an uncrewed test landing on the Moon and an unprecedented launch of Starship from the lunar surface using cryogenic fuels—liquid oxygen and methane.

Given the need for a smooth Artemis II flight in September 2025, all of the work on Starship, and the uncertain development of commercial spacesuits, is September 2026 a viable time frame for the mission? Or, as Ars asked during the teleconference, is it an aspirational date?

In response, Free said he firmly believed the schedule was "realistic" and emphasized that NASA's contractors agreed to meet those dates.

"We have 11 people in industry on here that have signed contracts to meet those dates," Free said of the teleconference call. "So from my perspective, the people in industry are here today saying we support it. We've signed contracts to those dates on the government side, based on the technical details that they've given us, that our technical teams have come forward with."

Then, Free added an important caveat: "It is, of course, not without risk." Not without a fair amount of risk, most likely.