NASA’s second attempt to run a “wet test” of the Space Launch System (SLS) for its Artemis II mission was successful. Following a failure of some seals during the first attempt earlier this month, NASA pushed the launch back to March to conduct additional tests. As of Thursday, those tests are complete, and they appear to have gone relatively smoothly.
Artemis II was originally planned to launch as early as Feb. 6, but during the wet test ahead of that, hydrogen fuel leaked enough to cause major delays in fueling. The faux countdown was scrubbed with five minutes to go, as the hydrogen buildup was potentially dangerous. This time around, NASA replaced the seals and partially filled the tanks on Feb. 12 to test them. When that went well, it went ahead with its full wet test on Feb. 19, and that went well, too.
NASA was able to fill the SLS’s two main tanks with a combined 730,000 gallons of liquid hydrogen and oxygen, and the seals held. NASA also confirmed the successful closing of the Orion crew module hatch and that the emergency abort system was in place and ready to work if required.
“During terminal count, automated systems take control of countdown operations, final checks of flight computers, engine bleed systems, and ground support equipment occur, and the rocket transitions to internal power, and the countdown proceeds toward simulated engine start,” reads NASA’s mission blog.
To be fair, the tests weren’t flawless. NASA had to pause the second countdown attempt due to a “booster avionics system voltage anomaly.” The countdown timer was then restarted, stopping only at the planned T-minus 33 seconds and T-minus 29 seconds.
The next available launch window for Artemis II runs from March 6 through 9, with March 11 as a possible fallback date. If March doesn’t work out, NASA will attempt to launch the mission in April.
