What Happens Now After NASA Called Off Its Mega Moon Rocket Test?

NASA has now tried twice to test out its new mega moon rocket, the Space Launch System (SLS). The first attempt at a "wet dress rehearsal" for the SLS began on Sunday, April 3, but was scrubbed part way through due to a fan safety issue. The agency tried again on Monday, April 4, but this test was also called off due to a problem with the core stage vent valve. The idea of the wet dress rehearsal is to test out all of the procedures that would go ahead before a rocket is actually launched. That involves rolling the rocket out to its launch pad and filling it with liquid fuel before running a countdown clock. Engineers test to make sure everything is working as expected, and that they can recycle the countdown clock if necessary. The rocket is not actually launched during this test, but all its systems are powered on as if it were a real launch.

The wet dress rehearsal is the final major test before a rocket is ready for an actual launch. In a project as complicated as SLS — which NASA intends to eventually use for carrying astronauts to the moon and even beyond that — experts generally concur that issues are to be expected during testing. However, given that SLS is significantly behind schedule and over budget, the two test failures are not ideal for NASA.

During the first test, to which the media did not have live access, there was a problem with a safety system that uses fans to maintain pressure and keep dangerous gases out of the mobile launcher. "Technicians are unable to safely proceed with loading the propellants into the rocket's core stage and interim cryogenic propulsion stage without this capability," NASA wrote. In the second test, a different issue occurred with the system: when the team was getting ready to fill the rocket with fuel, something went wrong with a panel controls a vent valve on the rocket. This happened late on April 4, so the decision was made to stop the test for the night and to investigate.

The next day, NASA announced that, "Inspections after the second test showed the vent valve that prohibited the team from proceeding with loading liquid hydrogen was configured physically in a closed position, which prevented it from being commanded remotely to an open position. The valve positioning has since been corrected."

Even though the first two tests proved troublesome, NASA officials remain optimistic that the SLS rocket will soon be ready. "We take pride in learning from these tests and we're taking the time to apply those lessons learned and roll those into the next attempt," Artemis Mission Manager Mike Sarafin said in a press conference. "We're going to get past a partially successful test that we had earlier this week and we anticipate that we'll have a fully successful test in short order." Sarafin reiterated the positive aspects of the test so far, pointing out that they had not experienced any serious or fundamental design problems, but what he described as nuisance or technical issues.

NASA has not yet announced when its next attempt at a wet dress rehearsal will take place, but it will be after the Axiom Space launch to the International Space Station, scheduled for Friday April 8. After that, the team is still hoping they might be able to meet the launch window for the Artemis I mission, which is scheduled for June. "We're not ready to give up on it yet," Sarafin said.