The second attempt at the final, crucial prelaunch test for NASA’s Artemis I mission to the moon was scrubbed on Monday.
The wet dress rehearsal, as NASA calls it, simulates every stage of launch without the rocket actually leaving the launchpad.
This includes powering on the 322-foot-tall (98-meter-tall) Space Launch System rocket and Orion spacecraft, loading supercold propellant into the rocket’s tanks, going through a full countdown simulating launch, resetting the countdown clock and draining the rocket tanks.
The test was originally scheduled to be completed on Sunday but was put on hold before the propellant was loaded. That was due to problems with two fans used to provide pressure to the mobile launcher – the movable tower which the rocket sits upon before it lifts off.
NASA said Monday it was able overnight to resolve the malfunction of the fans, which are needed to pressurize enclosed areas inside the launcher and keep out hazardous gases.
However, the rehearsal was stopped for the second time Monday due to a vent valve issue, NASA announced via Twitter.
“Due the vent valve issue, the launch director has called off the test for the day. The team is preparing to offload LOX and will begin discussing how quickly the vehicle can be turned around for the next attempt. A lot of great learning and progress today.”
Sunday’s delay came after the rocket weathered four lightening strikes during a powerful thunderstorm at Kennedy Space Center on Saturday. However, the fan issue that forced Sunday’s delay was not thought to be connected to the storm, NASA said.
The results of the wet dress rehearsal will determine when the uncrewed Artemis I will launch on a mission that goes beyond the moon and returns to Earth. The uncrewed mission is expected to launch in June or July.
This mission will kick off NASA’s Artemis program, which is expected to return humans to the moon and land the first woman and the first person of color on the lunar surface by 2025.
During the flight, the uncrewed Orion spacecraft will launch atop the SLS rocket to reach the moon and travel thousands of miles beyond it – farther than any spacecraft intended to carry humans has ever traveled. This mission is expected to last for a few weeks and will end with Orion splashing down in the Pacific Ocean.
Artemis I will be the final proving ground for Orion before the spacecraft carries astronauts to the moon, 1,000 times farther from Earth than where the International Space Station is located.
After the uncrewed Artemis I flight, Artemis II will be a crewed flyby of the moon, and Artemis III will return astronauts to the lunar surface. The time line for the subsequent mission launches depends on the results of the Artemis I mission.