NASA’s fourth attempt at a crucial refueling test of its large Moonrocket was largely a success, if not a complete one.
NASA rolled its Space Launch System (SLS) rocket and Orion spacecraft to launch pad 39B at Kennedy Space Center on June 6 in preparation for an attempted “wet dress rehearsal.” One such process involves pumping in and out of cryogenic propellant and a simulated launch countdown to test vital ground and flight control systems.
“When we do a dress rehearsal,” NASA Deputy Assistant Administrator Tom Whitmeyer said in a post-test press conference, “we’re rehearsing the ability to get the rocket ready to fly.”
Nasa began wet dress rehearsal just after 7 a.m. EDT Monday, successfully loading both stages of the rocket with propellants — liquid hydrogen and liquid oxygen — for the first time. However, a hydrogen leak occurring during the refueling process would cause the simulated countdown to momentarily stop at T-minus 29 seconds into the countdown.
“Our original plan was to go to T-minus 9.34 seconds,” said Charlie Blackwell-Thompson, launch director for NASA’s exploration ground systems program, in a press conference after the test.
Despite the cut to the countdown portion of the test, Nasa officials Tuesday said the test met most of its goals, though they didn’t detail what items were still pending.
“I would say we’re in the 90th percentile of where we need to be overall,” said Michael Sarafin, NASA’s Artemis Moon mission manager. “Nevertheless, there are still some outstanding issues that we need to look at.”
The SLS and Orion are the cornerstones of Nasa’s Artemis Moon program, and the space agency plans to use them to ferry astronauts back to the lunar surface in 2025 as part of the Artemis III mission. But before that, Artemis II will be carrying astronauts on a lunar flyby in 2023, and before that, Artemis I, an unmanned test flight of both vehicles, needs to take to the skies.
After the previous three attempts at the wet dress rehearsal, Nasa officials determined that successful completion of the test was necessary before Artemis I could launch.
Nasa first attempted a wet dress rehearsal on April 3, but defective fans designed to handle hazardous gases on the rocket’s mobile launch platform ended the test. The second attempt on April 4 was aborted midway when a pressure valve on the mobile launch vehicle platform malfunctioned, while the third failed on April 14 due to a liquid hydrogen leak in the rocket’s refueling connection.
Nasa rolled the SLS back into Kennedy Space Center’s vehicle assembly building on April 25 to fix the malfunctions, while launch windows for Artemis I were pushed back from May to June, July and most recently late August.
As of Tuesday, NASA officials were yet to commit to a new launch date for Artemis I.
“We really need to sit down and do everything that we just talked about,” Mr. Whitmeyer said, “look at the goals, look at what we’ve accomplished and see what additional work might be needed.”