SLS returns to the pad for next Artemis launch attempt

The Space Launch System and Orion spacecraft rolled back out to the launch pad Nov. 4 as the agency prepares for the third attempt to launch the vehicle on Artemis 1 mission later this month. SLS and Orion, on its mobile launch platform, arrived at Launch Complex 39B at 8:30 a.m. Eastern Nov. 4, a little more than nine hours after emerging from the Vehicle Assembly Building. The rollout was the fourth for the vehicle since March. The rollout supports NASA’s plans to conduct the next Artemis 1 launch attempt Nov. 14, with liftoff scheduled at 12:07 a.m. Eastern at the beginning of a 69-minute launch window. Two backup windows are reserved for Nov. 16 and Nov. 19. In a Nov, 3 call with reporters, Jim Free, associate administrator for exploration systems development, said managers gave the go-ahead for the rollout after reviewing weather forecasts that show the risk of a tropical storm system forming and heading towards Florida early next week. “Our engineering team thought it was an OK risk to go out tonight,” he said. Mark Burger, launch weather officer with the U.S. Space Force’s Space Launch Delta 45, said there is only a 30% chance of the system becoming a named storm, with peak wind gusts not expected to exceed 74 kilometers per hour. “Those are well within our constraints for riding out” the storm at the pad, he said. “We’ll have impacts from that in terms of the wind, but we’re not looking at any likelihood at this point of see a strong system emerge out of this.” SLS and Orion had been in the VAB since late September, when NASA rolled back to protect the vehicle from Hurricane Ian. Before the storm forced the rollback, agency officials felt they had resolved hydrogen leak problems that scrubbed the previous launch attempt Sept. 3.

The Space Launch System rocket and Orion spacecraft emerge from the Vehicle Assembly Building to head to Launch Complex 39B for a Nov. 14 launch. Credit: Jordan Sirokie

The investigation into that leak has not turned up a single clear cause. “There’s not really a smoking gun, per se,” said Cliff Lanham, senior vehicle operations manager in NASA’s Exploration Ground Systems program. “We feel pretty confident that, through the loading procedures and controlling the pressures, we understand it much better now.”

“Our teams have continued to grow and learn about the vehicle, and we’re confident,” said Free, who added he felt they had three good opportunities to launch. “But, it’s a flight test.”

“What we’ve learned in every wet dress [rehearsal], our two launch attempts and our tanking test help build our confidence,” he said. “I don’t think we would roll out if we didn’t feel confident.”

If the vehicle does not launch by Nov. 19, there is a fourth possible launch window on Nov. 25. Beyond that, Free said NASA would likely leave the vehicle on the pad and wait until the next launch period opens in December, which would require getting waivers from the Eastern Range for the SLS flight termination system, much like what happened in September.

December also marks the deadline for the lifetime of the two solid rocket boosters. Lanham said that the boosters, which originally had a 12-month life when they were stacked in early 2021, have been certified through Dec. 9 for one booster and Dec. 14 for the other. If the vehicle doesn’t launch by then, Free said, they would do another “analysis cycle” on the boosters to see if their lives can be further extended.