NASA on Sunday morning shortened a practice countdown for its new megacoet, the space launch system. It is a key component of upcoming missions to return 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 will depend on other components to land them on the moon’s surface, exceeds the budget of billions of dollars and years behind schedule.
Exercise over the weekend, which NASA calls wet clothing testing, is the latest major test before the rocket launches on its first unmanned test flight, which could take place as early as this summer. By simulating a countdown without the excitement of engines running and a rocket soaring into space, NASA hoped to solve problems with equipment and procedures.
The test, which began Friday night, was “wet” because it had to include pumping more than 700,000 gallons of liquid oxygen and liquid hydrogen into the rocket’s propellant tanks.
On Saturday afternoon, heavy storms passed over the launch site, with four lightning strikes protection towers around the rocket and the launcher. Launch preparation work had 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 general rehearsal was more than three hours late. The shutdown then occurred just before the thrusters began to flow. NASA said the problem was found in the mobile launcher, or mobile tower with numerous systems used to handle the rocket on the ground before it took off. Fans that create a positive air pressure in the enclosed areas of the mobile launcher did not work. Positive pressure is needed to prevent the build-up of hazardous gases, including those that could ignite.
The fan has been in operation since the mobile launcher moved to the launch site last month and continued to operate during Saturday’s storm, Charlie Blackwell-Thompson, the launch director, said during a press conference Sunday evening.
For propellant loading, 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 think this was related to lightning,” Ms. Blackwell-Thompson.
At that time, a safety fan also failed, apparently for a different reason, which caused the countdown to stop.
“We decided we really wanted to understand, since it was the first time the vehicle had been loaded,” Ms. Blackwell-Thompson. “And we made the decision to stay down.”
On Monday, the loading of propellers will begin at 7 a.m. Eastern time, and the exercise will end in the afternoon. If the trial runs into more trouble, another attempt may be possible on Tuesday.
The first test flight of the space launch system, Artemis 1, could take place this summer with the Orion capsule traveling around the Moon and back to Earth with no astronauts on board. The second Artemis flight, scheduled for 2024, would have astronauts on board for the same trip. Artemis 3 will be the first lunar landing of astronauts since 1972. NASA has proposed a date for 2025 for this manned trip, but it could face further delays.