Fuel leak sabotages NASA’s second attempt to launch a lunar rocket

Cape Canaveral, Fla. (AP) — NASA’s Crescent rocket suffered another dangerous fuel leak Saturday, forcing launch controllers to cancel a second attempt this week to put a crew on a capsule Sent into lunar orbit with a test dummy. The inaugural flight is now grounded for at least a few weeks, if not months.

The last attempt to launch the 322-foot (98-meter) Space Launch System rocket on Monday, the most powerful rocket NASA has ever built, is smaller but also plagued by hydrogen leaks. This is on top of a leak discovered during a countdown exercise earlier this year.

After the recent setback, mission managers decided to tow the rocket from the launch pad into the hangar for further repairs and system updates. Some work and testing may take place on the launch pad before the rocket moves.

In just a few days, a two-week launch blackout looms, and the rocket is now grounded until later this month or even October. NASA will work around a high-priority SpaceX astronaut flight to the International Space Station scheduled for early October.

NASA Administrator Bill Nelson emphasized that safety is a top priority, especially during a test flight like this, where everyone wants to validate the rocket’s systems “before we put four people on it.”

“Remember: we won’t launch until it’s right,” he said.

NASA has been waiting for years to send a crew capsule on a rocket to orbit the moon. If the six-week demonstration is successful, astronauts could fly around the moon in 2024 and land on the moon in 2025. The last time humans walked on the moon was 50 years ago.

Launch Director Charlie Blackwell-Thompson and her team had just started loading nearly 1 million gallons of fuel into the SLS rocket at dawn when a large leak suddenly appeared in the engine section at the bottom.

Ground controllers tried to plug it the same way they dealt with previous leaks: stopping and restarting the flow of ultracold liquid hydrogen in hopes of filling gaps around seals in the supply lines. In fact, they tried twice and also flushed helium through the line. But the leak is still there.

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After three to four hours of futile effort, Blackwell-Thompson finally stopped the countdown.

Mission manager Mike Sarafin told reporters it was too early to tell the cause of the leak, but it could be due to an accidental overpressurization of the hydrogen line earlier in the morning when the order was sent to the wrong valve.

“It’s not a controlled leak,” Sarafin said.

During Monday’s attempt, a series of smaller, unrelated hydrogen leaks emerged from the rocket. Technicians tightened the fittings over the next few days, but Blackwell-Thompson warned she won’t know if everything is tight until Saturday’s refueling.

Hydrogen molecules are very small – the smallest in existence – and even the smallest gap or crevice can provide a way out. The now-retired NASA space shuttle has been plagued by hydrogen leaks. Crescent rockets use the same type of main engine.

The bigger problem on Monday was that a sensor showed one of the rocket’s four engines was too hot, but engineers later confirmed it was actually cold enough. The launch team plans to ignore the faulty sensor this time around and rely on other instruments to ensure each host is properly cooled. But the countdown never went that far.

Mission managers accepted the additional risk posed by the engine problem as well as a separate problem: cracks in the rocket’s insulating foam. But they acknowledged other issues – such as fuel leaks – could cause another delay.

That hasn’t stopped thousands of people from cramming into the shore hoping to see a Space Launch System rocket soar. Local authorities are expecting large crowds due to the Labor Day long weekend.

The $4.1 billion test flight is the first step in a re-exploration of the moon by NASA’s Artemis program, named after the twin sisters of Apollo in Greek mythology.

Artemis is years behind schedule and billions of dollars in budget overruns, aiming to establish a sustained human presence on the moon, where crews end up staying for weeks. It is thought to be a training ground for Mars.

During the Apollo program, 12 astronauts walked on the moon, the last time in 1972.


The Associated Press Health and Science Division was supported by the Howard Hughes Medical Institute Division of Science Education. The Associated Press is solely responsible for all content.

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