NASA’s Artemis moonshot delayed until March after hydrogen fuel leaks during Space Launch System dress rehearsal

CAPE CANAVERAL, Florida (AP) – NASA’s much-anticipated Artemis moonshot with astronauts has been pushed back to at least March after hydrogen fuel leaks disrupted the dress rehearsal for its huge new rocket.

The issue echoes the same hydrogen-leak trouble that postponed the Space Launch System (SLS) rocket’s first outing three years ago. That initial test flight ended up on hold for months because leaking hydrogen is both highly flammable and hazardous.

"Actually, this one caught us off guard," NASA’s John Honeycutt said on Tuesday, just hours after the test was abruptly stopped at Kennedy Space Center.

Before the frustrating leaks surfaced, the agency had been aiming for a launch as early as this weekend, which would have marked humanity’s first journey to the moon in more than half a century.

"When you're dealing with hydrogen, it's a small molecule. It's highly energetic and we like it for that reason and we do the best we can," Honeycutt said.

NASA’s Artemis moonshot delay: what the extra month is for

Officials said the roughly month-long slip will give the launch team time to run another fuelling test before committing the four astronauts-three from the US and one from Canada-to a lunar fly-by. For now, it is too early to say when the countdown dress rehearsal could be attempted again.

Managers said any work on deformed or damaged seals, or other parts, will probably be achievable at the launch pad. Taking the rocket back to the Vehicle Assembly Building would likely extend the delay further.

What happened during the Space Launch System dress rehearsal

The leaks appeared early during Monday’s loading operations and then returned hours later, eventually freezing the countdown clocks at the five-minute point. Controllers had hoped to run the clock down to 30 seconds, but the escaping hydrogen surpassed safety thresholds.

NASA paused the flow of liquid hydrogen-at −253 °C (−423 °F)-multiple times in a bid to warm the area between the rocket and the fuel lines and, in theory, help any loose seals reseat. That approach did not resolve the problem, and neither did changing the hydrogen flow rate-tweaks that ultimately helped the first SLS rocket lift off uncrewed in 2022.

With the next attempt now no earlier than 6 March, commander Reid Wiseman and the rest of the crew were cleared to come out of quarantine in Houston. They will go back into quarantine two weeks ahead of the next launch try.

Wiseman wrote on the social platform X that he was pleased with the rehearsal, "especially knowing how challenging the scenario was for our launch team doing the dangerous and unforgiving work."

Orion capsule, cold weather, and why NASA calls SLS experimental

Officials said the unusually cold conditions at the launch site were not a factor in the hydrogen leaks or any other issues. Heaters kept the Orion capsule warm on top of the 322-foot (98-metre) rocket, while continuous purging safeguarded the rocket and ground equipment.

NASA associate administrator Amit Kshatriya emphasised that the Space Launch System is "an experimental vehicle," and that further lessons still need to be learned. He also noted that long gaps between fuelling tests and flights are unhelpful.

"I'm just reminded again almost four days and 40 years from Challenger, nobody sitting in one of these chairs needs to be calling any of these vehicles operational," Kshatriya told a news conference.

NASA typically has only a limited number of days in any given month when it can send the crew around the moon-the first time astronauts will travel there since 1972.

During the nearly 10-day mission, they will not land on the moon or even enter lunar orbit. Instead, the flight is intended to assess life support and other critical capsule systems in preparation for a lunar landing by other astronauts in the coming years.

In the 1960s and 1970s Apollo era, NASA sent 24 astronauts to the moon. The new Artemis programme is targeting fresh ground-the moon’s south polar region-and is intended to keep crews on the lunar surface for far longer stays.