Artemis

NASA Says It’s Satisfied With Rehearsal for SLS Moon Rocket Launch

NASA says it’s finished with having to do full-scale dress rehearsals for the first liftoff of its moon-bound Space Launch System rocket. But it’s not finished with having to make fixes.

“At this point we’ve determined that we’ve successfully completed the evaluations and the work that we intended to complete for the dress rehearsal,” Thomas Whitmeyer, NASA’s deputy associate administrator for common exploration systems development, told reporters today.

NASA’s assessment came after a dress rehearsal that reached its climax on June 20 with the loading of the 322-foot-tall rocket’s supercooled propellant tanks. The rehearsal, which followed some less-than-fully-successful trial runs in April, marked a milestone for launch preparations because it was the first time that the team at Kennedy Space Center in Florida had fully loaded all of the tanks and proceeded into the terminal launch countdown.

Mission managers had hoped to get as far into the countdown as the engine start sequence at T-minus-9.34 seconds. But during this week’s rehearsal, launch controllers encountered a hydrogen leak in a quick-disconnect attachment that’s part of the fueling system. The team tried to fix the leak by warming up the attachment, and then cooling it back down to realign a seal, but the fix didn’t work. In the end, the count was stopped at T-minus-29 seconds.

Even though the rehearsal at Launch Complex 39B ended slightly earlier than originally planned, NASA officials said they were satisfied with the objectives that were achieved — including practicing the procedure for unloading propellant from the rocket. “Our Artemis launch team has worked quickly to adapt to the dynamics of propellant loading operations,” Charlie Blackwell-Thompson, Artemis launch director at Kennedy Space Center, said in a news release.

Most of the 13 additional commands that would have been executed in the remaining seconds of the launch-pad trial run had been validated during earlier ground tests, said Phil Weber, senior technical integration manager for NASA’s Exploration Ground Systems Program.

Over the next few days, engineers will conduct some follow-up tests at the launch pad, including a checkout of the booster hydraulic power unit that would have come into play just after T-minus-29 seconds.

NASA plans to roll the 3.5 million-pound rocket back to Kennedy Space Center’s Vehicle Assembly Building in a week. Once it’s back inside the VAB, engineers will replace a seal on the troublesome quick-disconnect attachment.

The SLS and its Orion space capsule are slated to be brought back to Launch Complex 39B in late August, kicking off the final stage of preparations for the Artemis 1 mission. NASA said it would set a specific target launch date after the hardware associated with the hydrogen leak is replaced. The first open launch window extends from Aug. 23 to Sept. 6.

Artemis 1 calls for sending the uncrewed Orion capsule on a flight that would go into lunar orbit and return to Earth. Artemis 1 would be followed by a crewed round-the-moon flight in the 2024 time frame, known as Artemis 2. The mission after that, Artemis 3, calls for putting astronauts on the moon in 2025.

Lead image: A full moon looms over NASA’s Space Launch System and its Orion capsule at Kennedy Space Center’s Launch Complex 39B, Source: NASA / Ben Smegelsky

Alan Boyle

Science writer Alan Boyle is the creator of Cosmic Log, a veteran of MSNBC.com and NBC News Digital, and the author of "The Case for Pluto." He's based in Seattle, but the cosmos is his home.

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