NASA has been pushing canceled the launch of its Artemis 1 mission to the moon due to a problem with one of the engines on the giant SLS rocket.
With 40 minutes left on the countdown clock at Kennedy Space Center in Florida, Mission Control announced an unscheduled stop as technicians investigated a problem encountered when loading the SLS rocket’s core stage with more than 700,000 gallons of liquid hydrogen and liquid Oxygen supercooling occurred to a frigid -423 and -297 degrees Fahrenheit. The problem was with the third RS-25 engine, one of the engines next to the right solid rocket booster. The flow of liquid hydrogen into the engine compartment was not working as it should and the propellant was not in the correct temperature range.
Engineers added the issue to their checklist during the last “wet dress rehearsal” in June, during which they practiced refueling and running the countdown sequence to within 29 seconds of takeoff. However, they were unable to test it at the time because of a leak of liquid hydrogen.
That morning, the team also discovered a problem with a vent valve, and a gathering rainstorm and the possibility of lightning strikes also posed risks. After more than an hour of troubleshooting, Launch Director Charlie Blackwell-Thompson called today’s attempt a scrub.
At a press conference held just after 1 p.m. ET, NASA officials did not set a specific date for the next attempt. “Friday is definitely still in the game,” said Artemis Mission Manager Mike Sarafin, referring to September 2nd, the next planned launch window. When asked by reporters for details on how likely a Friday launch would be, he called it a “non-zero chance,” too much laughter from people in the room. The next possible start date, if Friday is not an option, is September 5th.
None of the officials — including NASA Administrator Bill Nelson and Jim Free, the agency’s assistant administrator for the Exploration Systems Development Mission Directorate — were ready to say whether a longer delay and more serious repairs would be needed. “We won’t have all the data and implications today, but we felt we owed it to you to share our knowledge,” Free said.
Speaking on the space agency’s livestream this morning, shortly after the launch was scrubbed, Nelson stressed the need to resolve any issues. “We don’t start until it’s right,” Nelson said. “It’s just an example of how this is a very complicated system and all these things have to work. They don’t want to light the candle until it’s ready.” He cited the example of the 24th space shuttle launch in 1986, which was scrubbed four times before launching “a flawless mission”.
The first Artemis flight will be unmanned. After launch, the Orion capsule will depart with three mannequins on a 42-day mission that will span multiple orbits around the moon and 40,000 miles beyond before returning to Earth and landing in the Pacific Ocean near San Diego. Its reentry will serve as a test of a new heat shield material called Avcoat, and the mission will also continuously collect performance metrics as well as radiation data from sensors worn by the mannequins.