NASA Administrator Bill Nelson (left) meets with members of the “red crew” after they repaired a hydrogen leak at the Artemis 1 moon rocket’s launch pad. The red crew members, from left to right, were Billy Cairns, cryogenic engineering technician; Chad Garrett, safety engineer; and Trent Annis, cryogenic engineering technician. Credit: NASA/Sam Lott
NASA’s Space Launch System moon rocket relied on advanced guidance algorithms, powerful cryogenic engines, and millions of lines of software code to get it off the ground for the first time Wednesday. But “there are also times when you’ve just got to put a wrench on a nut,” NASA’s Artemis ground systems program manager said.
That’s what NASA did in the final hours of the Artemis 1 mission’s countdown late Tuesday night, when the launch team called upon a “red crew” of two specially-trained technicians and a safety engineer to torque nuts around a leaky hydrogen valve inside a compartment on the moon rocket’s mobile launch platform.
Trent Annis, Billy Cairns, and Chad Garrett drove to pad 39B with the 322-foot-tall SLS moon rocket loaded with three-quarters of a million pounds of combustive hydrogen fuel and liquid oxygen. The cryogenic propellants need to be slowly replenished throughout the countdown as the fluids boil off, and the valve responsible for continuing to feed hydrogen into the core stage of the rocket was leaking.
They spent nearly an hour at the launch pad. The red crew personnel climbed stairs to reach the “zero deck” of the mobile launch platform, then walked across the 158-foot by 133-foot deck to take another set of stairs down into a compartment near the side of the structure. The platform is the table on which the SLS moon rocket sat during the countdown.
“We went up there and tightened her up,” Annis said in an interview aired on NASA TV after the launch.
“All I can say is we were very excited,” he said. “I was ready to get up there and go.”
That’s what NASA did during the Artemis countdown Tuesday night, when a “red crew” of two technicians & a safety engineer drove to pad 39B with the SLS moon rocket filled with combustive fuel to fix a leak.
Hear Trent Annis talk about the experience.
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Red crews are sometimes used during launch countdowns to accomplish hands-on tasks at the launch pad, such as adjusting valves or repairing broken equipment. Red crews went to the launch pad during space shuttle countdowns, and other launch providers, such as United Launch Alliance, also make regular use of their services. Notably, NASA sent a similar red crew to the launch pad during the countdown for the Apollo 11 moon landing mission in 1969 to tighten bolts and repair a leak, allowing the Saturn 5 rocket to take off for the moon with Neil Armstrong, Buzz Aldrin, and Michael Collins.
But NASA considers it to be a hazardous operation, and red crew personnel are trained to work near a fully fueled rocket.
“I’d say we were very focused on what was happening up there, just making sure we knew what was happening because the rocket, it’s alive, it’s creaking, it’s making venting noises, its’s pretty scary,” Annis said. “So on zero deck my heart was pumping. My nerves were going, but yeah, we showed up today. As soon as we walked up those stairs we were ready to rock and roll.”
The red team has finished their work at pad 39B after tightening bolts on a leaky hydrogen replenishment valve.
— Spaceflight Now (@SpaceflightNow)
In the end, the red crew’s work at the pad resolved the leak, and NASA’s launch controllers continued the countdown. The huge moon rocket blasted off at 1:47 a.m. EST (0647 GMT) Wednesday after a 43-minute delay to allow the red crew to fix the leak.
“I was very comfortable, very confident in the test team and the procedures and our training,” said Garrett, the red crew’s safety engineer. “We did a great job.”
The red crew members are employees of Jacobs, a NASA contractor that manages ground operations at Kennedy Space Center to support the Artemis moon program.
NASA’s Artemis 1 test flight marked the first launch of the SLS moon rocket after a decade in development. The launcher propelled NASA’s Orion spacecraft on a trajectory toward the moon to kick off a 25-day demonstration mission that will pave the way for future human expeditions to return astronauts to the moon for the first time since 1972.