NASA will not attempt to launch its Space Launch System in the coming days, skipping the potential launch windows of Monday and Tuesday, the agency announced today. The announcement comes after two scrubbed launch attempts of the massive rocket and is expected to be delayed by several weeks.
August 29, 2022 is expected to be the first launch of the Space Launch System (SLS). That launch attempt was scrapped after engineers noticed a problem with the temperature of one of the rocket’s four engines. Today, a second launch attempt failed with a persistent hydrogen leak, which Artemis mission manager Michael Sarafin described as “huge” at a press conference after the scrub. A small hydrogen leak was also observed during the 29th attempt, but this was much larger.
The launch, whenever it happens, will be the first for NASA’s SLS, an expensive, long-delayed rocket that has been in development for more than a decade. The rocket is set to launch an uncrewed capsule called Orion on a mission called Artemis I. The mission was designed as a test flight that would pave the way for future missions that would carry astronauts to the Moon.
NASA has not announced when Artemis I’s next launch attempt will be, but hopes to have a better idea in a few days. Engineers focused on a part of the fuel system that helps pump liquid hydrogen fuel into the rocket and can be quickly disconnected from the rocket after refueling. This “quick disconnect” has a seal around it, designed to keep hydrogen from escaping, referred to as “soft goods”. One solution being considered is to remove and replace the soft material around the quick disconnect.
Engineering teams are currently in the Vehicle Assembly Building (VAB) trying to figure out if it’s better to do this replacement and fix any other issues or if they should stay on pad. Both approaches have disadvantages and advantages. As Sarafin noted, if NASA had been on the pad, they could have tested the system at cryogenic temperatures, which would have given them a better idea of how it would behave during a real launch. The downside is that NASA would also have to build an environmental enclosure to house the pad. If they go back into the VAB, the building itself will serve as an environmental enclosure. While NASA can replace and test problematic components inside the VAB, it can only do so at ambient temperature — not cryogenically.
After Saturday’s second launch scrub, NASA Administrator Bill Nelson said the next launch attempt would take place in mid-to-late October, after a planned crewed mission to the International Space Station, if the SLS returns to the VAB for repairs. It will take off at the beginning of the month. The process of rolling the Megarocket back to the VAB takes several hours.
There is another trick. When the rocket touched down on the pad on August 16, another timer started. NASA has 20 days to launch the rocket before rolling it back to test the batteries in the rocket’s flight termination system. The termination system is the part of the rocket that the space force can use to destroy the rocket if anything goes wrong during launch and flight. NASA got approval to extend it to 25 days, but that time is almost up. Unless NASA gets another extension, it will have to go back to VAB anyway.
“We won’t launch until we think it’s right,” NASA Administrator Bill Nelson said at a press conference. “So I see this as part of our space program, of which safety is at the top of our list.”