NASA on Sunday morning cut off the countdown to its new megarocket, the Space Launch System. This is a key component of the upcoming missions to return the astronauts to the moon, and the agency said there was a problem with the mobile launch tower.
NASA will try again on Monday.
The 322-foot-tall rocket and its Orion capsule are crucial components for Artemis, NASA’s moon landing program. The system, which can launch astronauts into lunar orbit but rely on other components to land them on the moon, costs billions of dollars above budget and is behind schedule.
The weekend exercise, which NASA calls a wet dress rehearsal, is the latest major test before the rocket was launched on its first unmanned test flight, which could take place this summer. By simulating a countdown without the excitement of starting engines and launching a rocket into space, NASA hoped to fix problems with equipment and procedures.
The rehearsal, which began Friday night, was “wet” because it had to involve pumping more than 700,000 gallons of liquid oxygen and liquid hydrogen into the massive rocket’s fuel tanks.
On Saturday afternoon, strong thunderstorms passed over the place of launch, with four lightning strikes protective towers around the missile and the launcher. The starter’s preparatory work was supposed to be stopped during the storm, but after reviewing the data, NASA said there was no damage and the countdown could continue.
On Sunday, the dress rehearsal was more than three hours behind. The shutdown then occurred just before the propellants began to flow. NASA said the problem was found in a mobile launcher or mobile tower with multiple systems used to control the rocket on the ground before takeoff. Fans that create positive air pressure indoors on the mobile launcher did not work. Positive pressure is necessary to prevent the accumulation of hazardous gases, including flammable gases.
The fan has been running since the mobile starter was moved to the launch site last month and continued to operate during Saturday’s thunderstorm, said Charlie Blackwell-Thompson, director of the launch, during a press conference Sunday night.
To refuel, the fan switches to a different mode to blow more air. The fan ran in this mode for several hours before the problem occurred.
“We don’t believe it has anything to do with lightning,” said Blackwell-Thompson.
Then the backup fan also failed, apparently for another reason, which stopped the countdown.
“We decided we really wanted to understand that, given that this was the first load on the vehicle,” said Blackwell-Thompson. “And we decide to stay down.”
On Monday, refueling should begin at 7 am Eastern Time, and the exercise ends in the afternoon. If the rehearsal encounters more obstacles, a new experience on Tuesday may be possible.
The first test flight of the space launch system, Artemis 1, may take place this summer, with the Orion capsule traveling around the moon and back to Earth without astronauts on board. Artemis’ second flight, scheduled for 2024, will have astronauts on board for the same voyage. Artemis 3 will be the first astronaut landing on the moon since 1972. NASA has proposed a 2025 date for this crew trip, but it could face further delays.