After three previous aborted attempts, NASA successfully fueled its new massive deep-space rocket, the Space Launch System, for the first time on Monday — completing a critical milestone ahead of the vehicle’s first flight. However, there was a shadow over the achievement. The fueling was part of an elaborate dress rehearsal that ended 20 seconds earlier than NASA had planned, and it’s unclear if the agency got all the data and practice it needed to proceed with the rocket’s debut launch.
The Space Launch System, or SLS, is a key piece of NASA’s flagship Artemis program — an elaborate effort to send the first woman and the first person of color to the surface of the Moon. But first, SLS needs to actually fly, and before that can happen, NASA wanted to go through all of the intricate steps that lead up to an actual launch — except for the part where the rocket takes off.
With the SLS standing upright on its launchpad in Kennedy Space Center in Florida, NASA engineers and flight controllers filled the vehicle with its ultra-cold propellants on Monday, just as they would on a launch day. With all the SLS tanks full, the flight team counted down to a simulated liftoff time, with the plan to stop the countdown at roughly T-minus 9 seconds. Instead, the team stopped the countdown short at T-minus 29 seconds due to a hydrogen leak. NASA says it was able to complete most of its objectives for the test, primarily loading the vehicle with propellant — but that there are still a handful they weren’t able to get to with the premature cutoff.
“I would say that the majority of our objectives were met,” Charlie Blackwell-Thompson, the Artemis launch director at NASA, said during a press conference after the test. “There were maybe small pieces within that one primary objective that we came up a little short on.”
NASA has attempted this dress rehearsal three times before, and all of those attempts ended before flight controllers could fully load the rocket with propellant. After the third failed attempt, NASA rolled the SLS into the agency’s massive Vehicle Assembly Building to perform various repairs and upgrades before rolling the rocket back out onto the pad on June 6th.
Three of the biggest goals of the dress rehearsal included demonstrating that the flight team could load the vehicle up with propellant, stopping the countdown, and then draining the SLS of fuel — all of which were performed on Monday. Additionally, NASA was able to get into terminal countdown, the final phase of the countdown that begins T-minus 10 minutes prior to launch.
