NASA’s third attempt at Modified rehearsal The Space Launch System (SLS) was shut down Thursday when a liquid hydrogen leak was detected during tank operations. The space agency plans to conduct another lunar rocket test no later than April 21.
This is the latest in several setbacks at the rocket’s rehearsal, including delays due to weather, malfunctioning ventilation fans, and valve problems.
“All of the issues we’re facing are procedural and lessons learned,” said Mike Sarafin, Artemis’ mission manager, during a press conference Friday.
The rehearsal takes place when the 322-foot rocket is full of fuel while sitting atop the launch pad, and the team makes a mock countdown to prepare for launch day. Rehearsal is necessary to launch Artemis I, an unmanned mission to the moon and back, and the first step to returning humans to the moon by 2026.
This rehearsal was first scheduled for April 1, but was initially postponed due to technical issues that prevented the crew from being refueled. Ahead of the next test date on April 11, the team discovered a faulty valve, prompting them to adjust rehearsal and plan to refuel only the SLS’s base stage, not its upper stage.
Unfortunately, Thursday’s third attempt wasn’t the magic, as the team discovered a liquid hydrogen leak from the umbilical tail service mast, which connects the base of the mobile launcher to the base stage. Liquid hydrogen is one of the two propellants used in the rocket, the other being liquid oxygen.
By the time the rehearsal was stopped, about 49% of the tank was filled with liquid oxygen, and only 5% of the other tank was filled with liquid hydrogen. The team successfully cooled the lines used to load propellant into the upper stage, but was unable to flow any propellant into the stage due to a valve problem.
However, the team behind the SLS rocket says they haven’t given up. “There is no doubt in my mind that we will finish this testing campaign, that we will look at the hardware and the data will lead us to the next steps,” Artemis launch director Charlie Blackwell Thompson said during the conference call. “We’re going to launch this car… and we’ll be ready to fly.”