The Artemis 1 launch is likely to be delayed until October due to the SLS fuel leak

NASA’s next-generation Space Launch System will not fly in September. After a fuel leak forced the agency to scrub Artemis 1’s second launch attempt, there was some hope the mission would launch before the end of its current launch window on September 6. It won’t happen.

“We will not launch during this launch period,” Jim Free, NASA’s associate administrator for exploration systems development, told a room full of reporters after Saturday morning’s events. “This was not a manageable leak,” Artemis mission manager Michael Sarafin said, referring to the “quick disconnect” fitting that caused so much trouble for NASA yesterday. Ground crews at Kennedy Space Center tried to fix the problem three times before recommending a “no go” for Saturday’s launch.

According to Sarafin, the leak started after one of the fuel lines to Artemis 1’s core booster briefly and “inadvertently” overpressurized. An “erroneous” manual command from mission control triggered the incident. As of Saturday, Sarafin said it was too early to know if it was the cause of the fuel leak, but the rocket had enough flammable hydrogen gas that it was not safe to launch. “We want to be deliberate and cautious about drawing conclusions here, because the correlations are not necessarily the same,” he added.

Whatever the cause of the leak, NASA is now required to replace the non-metallic gasket that was meant to prevent hydrogen from escaping at the quick disconnect. The agency has two options for how to proceed. It can replace either the launch pad 39B or the gasket in KSC’s vehicle assembly building. Both have advantages and disadvantages.

Working on the pad will allow NASA to test the system at cryogenic temperatures. This will give the agency a better idea of ​​how the rocket will perform when it is ready to launch again. However, NASA needs to build an orbit around SLS. At VAB, meanwhile, the building will act as an enclosure but limit testing to ambient temperatures only.

Finally, since NASA is required to test the batteries in the vehicle’s flight termination system every 20 days, the SLS will likely end up at VAB. This system allows the Space Force to destroy a rocket if it flies off course or something goes wrong during flight. NASA can only test in a VAB, and the Space Force recently granted the agency a five-day extension to its usual deadline.

All told, the next earliest launch window for Artemis 1 will open on September 16 and then close on October 4. That opening includes a possible conflict with another mission. Space X’s Crew-5 flight is set to take off from Kennedy Space Center on October 3. So, NASA is aiming higher for the subsequent window, which opens on October 17 and runs through the end of the month. We’ll find out more next week when NASA holds another press conference, but NASA Administrator Bill Nelson was adamant that the agency won’t try to launch Artemis 1 until it thinks the SLS is ready to fly. “We don’t launch until we think it’s right,” he said. “I see this as part of our space program, of which safety is at the top of our list.”