NASA shortened Sunday morning countdown exercises for its massive new vehicle, the Space Launch System. A key component of upcoming missions will be to return astronauts to the moon, and the agency said there was a problem with the portable launch tower.
NASA will try again on Monday.
The 322-foot rocket and Orion capsule are core components of Artemis, NASA’s lunar landing program. The system, which can launch astronauts into lunar orbit but will rely on other components to land them on the moon, is billions of dollars over budget and years behind schedule.
The weekend exercise, which NASA calls Rehearsal, is the last major test before the rocket launches into its first uncrewed test flight, which could happen as soon as this summer. By simulating a countdown without triggering the ignition of the engines and the ascent of a rocket into space, NASA hoped to solve glitches in equipment and procedures.
The rehearsal, which began Friday night, was “wet” because it involved pumping more than 700,000 gallons of liquid oxygen and liquid hydrogen into the massive rocket’s fuel tanks.
On Saturday afternoon, severe thunderstorms passed over the launch site Four lightning strikes Protective turrets around the missile and launcher. Preparatory work on the launch pad had to be paused during the storm, but after reviewing the data, NASA said there was no damage and the countdown could continue.
On Sunday, the rehearsal was more than three hours late. Then the stop occurred before the start of the fuel flow. NASA said the problem was found in the mobile launch pad, or moving turret with many of the systems used to manage the rocket on the ground before it takes off. Fans that generate positive air pressure in areas closed to the portable player do not operate. Positive pressure is necessary to prevent the buildup of dangerous gases, including those that can ignite.
The fan has been running since the mobile launch platform was moved to the launch site last month and has continued to operate through Saturday’s thunderstorm, launch manager Charlie Blackwell Thompson said during a news conference Sunday night.
To load propellant, the fan is switched 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 is related to lightning,” Ms Blackwell Thompson said.
Then a backup fan also failed, apparently for a different reason, causing the countdown to stop.
“We decided we really wanted to understand that, given that it was the first time the car had been loaded,” said Ms Blackwell Thompson. “And we make a decision to stay.”
The propellant loading is scheduled to begin Monday at 7 a.m. ET with the exercise concluding in the afternoon. If the rehearsal encounters more obstacles, another attempt on Tuesday might be possible.
The first test flight of the space launch system, Artemis 1, could happen this summer as the Orion capsule travels around the moon and returns to Earth without astronauts on board. Artemis’ second flight, scheduled for 2024, will have astronauts on board on the same flight. Artemis 3 will be the first moon landing by astronauts since 1972. NASA has suggested a date for 2025 for that manned flight, but it may face further delays.