NASA is pressing ahead with plans to start a three-day dress rehearsal countdown for the agency's new SLS/Artemis-1 moon rocket on April 1, officials said Friday. The plan gives the test priority over the planned April 3 launch of a SpaceX Crew Dragon capsule for the first privately-funded civilian flight to the space station.
If SLS processing stays on schedule, the rocket will be loaded with propellant and the countdown will tick down to within 10 seconds of a make-believe launch on April 3. The actual launch of a Falcon 9 rocket from nearby pad 39A would then slip one or two days to give engineers time to replenish stores of nitrogen gas used at both launch pads.
But if the SLS team runs into problems leading up to the "wet dress rehearsal" and is delayed, the SpaceX flight, chartered by Houston-based Axiom Space, will take off on April 3 as had been planned, carrying a retired NASA astronaut and three wealthy entrepreneurs to the space station for an eight-day stay.
"Artemis 1 wet dress has the range," NASA space operations chief Kathy Lueders said after a formal flight readiness review. She was referring to U.S. Space Force tracking and telemetry support required for all East Coast launches. "Our plan is to get (the countdown test) done as early as possible."
NASA plans to launch the towering SLS rocket on its maiden flight, an unpiloted trip beyond the moon and back, in the early June timeframe. The team wants to get the countdown test done as soon as possible so they can move the rocket back into the protection of its processing hangar — and out of any threatening weather — for final pre-flight processing and to resolve any issues that might come up in the test.
But the Axiom-1, or AX-1, mission presents its own challenges. If the rocket is not off the pad by April 7, NASA's next Crew Dragon astronaut flight to the station, now targeted for launch on April 19, could be delayed, triggering a domino-like slip for the April 26 return to Earth of the four astronauts that crew is replacing.
Delays are an issue in part because of temperature constraints based on the space station's orbit with respect to the sun. Lueders said mission managers are in daily contact and the schedule should come into sharper focus over the next week or so.
"We've still got eight to 10 days of processing on both sides for us to (reach a decision)," she said. "So (SLS is) getting ready for their wet dress, but we and Axiom and the SpaceX team are also getting ready to be able to launch as closely to April 3 as possible."
To get a sense of the schedule complexities facing NASA and SpaceX, consider April 1. SpaceX plans to carry out a "dry" countdown rehearsal for the AX-1 team that morning, followed by launch of another Falcon 9 from pad 40 at the nearby Cape Canaveral Space Force Station, followed by a test firing of the AX-1 Falcon 9 on pad 39A. All that will be followed by the start of the SLS practice countdown.
Lueders said the busy launch schedule "is a good problem to have."
"From a planning perspective, it made a lot of sense to us to just get the wet dress mission done," she said. "It lets the Artemis team be able to go through that data and the reconfiguration (for flight) and then begin getting ready for what's going to be a really historic launch in June."
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