NASA engineers explained the reason behind Monday’s scrubbed launch of Artemis I as a problem getting one of the rocket’s engines to the proper temperature range required to start the engine at liftoff. Then they ran out of time in the two-hour launch window to continue toward a launch before 10:33 a.m. ET.
A team of mission managers will review data and meet on Tuesday to decide what to do next, including whether a Friday launch during a launch window starting at 12:48 p.m. ET will be merited.
Officials said the enormous Space Launch System rocket and Orion spacecraft remained in safe and stable condition as it remained sitting atop launch pad 39B at Kennedy Space Center in Florida.
An evaluation is underway for why a bleed test was not successful to get one of the RS-25 engines on the bottom of the core stage, engine 3, to the proper temperature range for liftoff. The focus during the hours before the launch was on engine 3 of four engines at the base of the rocket.
NASA Administrator Bill Nelson described the scrubbed launch as part of a lengthy process toward attaining a successful flight. “This is a brand-new rocket,” he said at an afternoon news conference. “It won’t fly until it’s ready. There are millions of components of this rocket and its systems. Needless to say, the complexity is daunting.”
“You don’t want to light the candle until it’s ready to go,” he said in earlier comments on NASA TV.
Nelson, a former astronaut and congressman, described having to be patient during four scrubbed launches of a Space Shuttle Columbia mission he was a part of 36 years ago that finally succeeded on the fifth try. “When you are dealing in a high- risk business such as space flight, that’s what you deal with. You make it as safe as possible and test it and make it as safe as possible.”
Nelson said Vice President Kamala Harris and congressional leaders were present at Kennedy Space Center for the planned launch event.
NASA explained that launch control teams normally condition the engines prior to launch by increasing pressure on the core stage tanks to bleed some of the cryogenic propellant to the engines to get them to the super cold temperature range needed to get them started.
Mike Sarafin, Artemis mission manager, said in addition to the issue of chilling down engine 3, an issue with a vent valve (later resolved) slowed preparations. In addition, weather concerns with lightning led to the decision to scrub.
“The team worked through a number of issues today and the team was tired and we decided to knock it off,” Sarafin said. “Again, it’s an incredibly hard business we have.” There was not an identified problem with engine 3 itself, he said, just one of cooling it properly. Further analysis will be conducted before a Friday launch or if other measures are needed, including rolling the rocket back to the massive Vehicle Assembly Building for further inspections and evaluations.
Jim Free, associate administrator for NASA’s Exploration Systems Development Mission Directorate, also defended the decision to scrub. “This is a really important time for us and it was the right thing to do,” he said. “We continue to learn and we’re testing the people and the processes.”
During the hours before the expected launch at 8:33 a.m. ET, contractors from Boeing and Aerojet Rocketdyne consulted in person with NASA engineers about engine 3 and related concerns, Sarafin said. Other leading contractors include Lockheed Martin, Northrop Grumman and Jacobs, although NASA earlier estimated as many as 4,000 companies have contributed parts or professional services to the mission.
Airbus is also a major contractor and partner with Lockheed Martin on the mission through its support of the European Space Agency in provisioning the European Service Module, which sits below the Crew Module (uncrewed for Artemis I) in the spacecraft to provide Orion with propulsion, power, water, oxygen, guidance and the right temperature. It is the first time NASA has relied on a non-U.S. company to build a mission-critical element for an American human spaceflight.
The bleed test on engine 3 had not been fully tested prior to Monday even though the Space Launch System had been through four prior tests. Nelson has repeatedly called Artemis I a test flight.
Artemis I is an uncrewed mission designed to test systems for successive missions to the Moon in 2024 and 2025 when the first woman is expected to step on the lunar surface.
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