Next SLS countdown rehearsal scheduled for June 19

WASHINGTON — NASA has tentatively scheduled the next attempt to fuel the Space Launch System and run a practice countdown for June 19, two weeks after the vehicle returns to the launch pad.

At a May 27 briefing, NASA officials said they were completing work on the rocket in the Vehicle Assembly Building at Kennedy Space Center. The missile returned to the VAB a month ago after three attempts to complete a wet dress rehearsal (WDR) at Launch Complex 39B in the first half of April.

Cliff Lanham, Senior Vehicle Operations Manager for NASA’s Exploration Ground Systems program, said a “call to stations” for the rollout is scheduled for the evening of June 5. The rollout will begin around midnight on June 6. That’s about six hours later than the first rollout in March, which he said is intended to make it less likely that thunderstorms will disrupt the rollout.

That would push NASA to make its fourth WDR attempt no earlier than June 19, depending on weather and any range restrictions, he said.

NASA hopes this fourth attempt will be successful, filling both the core stage and the upper stage with liquid hydrogen and liquid oxygen propellants and running a countdown that stops just before the core stage’s engines would ignite. However, Tom Whitmeyer, deputy assistant administrator for the development of common reconnaissance systems, said the agency “will add a small schedule this time to ensure that if we have to do more than one wet dress rehearsal, we’re ready to do that.” support. “

Whitmeyer and Lanham said they were confident workers had resolved issues encountered during April’s WDR attempts, including replacing a helium check valve in the top stage and tightening flange bolts on a power cable believed to be damaged. the cause of a hydrogen leak. “All the things we’ve seen so far have been very positive in terms of the actual performance of the hardware,” Whitmeyer said.

While the SLS was back in the VAB, Air Liquide, the contractor that manages the downtown nitrogen gas distribution system, completed an upgrade to increase the amount of gas available for SLS operations, an issue that cropped up during the earlier WDR attempts. That improved system completed a 34-hour test that exceeded the requirements for SLS, said John Blevins, NASA SLS chief engineer.

NASA also used the vehicle’s time to do some work planned for after the WDR. That included opening up the Orion spacecraft and installing some of the payloads it will carry on the unmanned Artemis 1 mission and removing instrumentation on the SLS used to measure the loads on it during the initial rollout. .

The work, Lanham said, “will really help us from a work volume point of view” that needs to be done after WDR to get the vehicle ready for launch. He didn’t estimate how much time NASA saved by doing that work early, but noted that doing so now avoids delays of “nonconformities” engineers encountered.

“It allows us to reduce demand for our resources as we move back into the VAB and, in my view, reduce the risk on our overall schedule to roll back before launch,” he said.

Agency officials have previously stated they will wait until after WDR is complete to set a formal launch date for Artemis 1, but Whitmeyer echoed recent statements from officials, including NASA administrator Bill Nelson, that NASA hopes to complete the mission. to launch in August. NASA has published launch windows for the mission from July 26 through August 10, excluding August 1, 2, and 6, as well as August 23 through September 6, excluding September 30, 31, and 1.

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