‘Large’ hydrogen leak foils NASA’s schedule for Artemis I mission

‘Large’ hydrogen leak foils NASA’s schedule for Artemis I mission

NASA will not attempt to launch its Space Launch System in the coming days, the agency announced today, skipping potential launch windows on Monday and Tuesday. The announcement comes after two scrubbed launch attempts of the massive rocket, and will likely result in a delay of several weeks.

August 29th, 2022 was supposed to be the debut launch of the Space Launch System (SLS). After engineers discovered an issue in one of four rocket engines’ temperature, the launch was canceled. Today, a second launch attempt was foiled by a persistent hydrogen leak that Artemis mission manager Michael Sarafin described as “large,” in a press conference after the scrub. A small hydrogen leak was also noticed during the attempt on the 29th, but this was much larger.

The launch, whenever it happens, will be the first for NASA’s SLS, a very expensive, extremely delayed rocket which has been in development for over a decade. It was designed to carry an uncrewed capsule named Orion, on a mission called Artemis I. This mission was intended to be a test flight and pave the way for future missions that will transport astronauts to orbit the Moon.

NASA is yet to announce the date for its next Artemis I launch, although it expects to know in the next few days. Engineers focus on the part of the fueling system which helps to send liquid hydrogen fuel into rockets and can then quickly disconnect from rocket after fueling. This “quick disconnect” has a seal around it that is designed to keep hydrogen from leaking out, which is referred to as “soft goods”. The quick disconnect can be fixed by removing the soft goods and replacing them.

Engineers are trying to decide if it is better to replace the quick disconnect and fix any issues in the Vehicle Assembly Building (VAB), or whether they should remain on the pad. There are risks and benefits to both approaches. Sarafin noted that NASA could stay on the pad to test their system at cryogenic temperatures. This would allow them to get a better understanding of the system’s behavior during real launches. NASA would need an enclosure for their pad stay. If they went back into the VAB, the building itself would act as an environmental enclosure. NASA can replace or test any of the parts in the VAB but it cannot do so at cryogenic temperatures.

Speaking soon after the second launch scrub on Saturday, NASA Administrator Bill Nelson said if the SLS rolls back into the VAB for repairs, the next launch attempt would most likely happen in mid to late October, after a planned crew mission to the International Space Station takes off earlier that month. It takes many hours to roll the megarocket into the VAB.

There’s also another problem. When the rocket rolled out to the pad on August 16th, another timer started. NASA had 20 days in which to launch the rocket before it would have to be rolled back in order to test the batteries in the rocket’s flight termination system. If something happens during launch or flight, the Space Force has the ability to use the termination system of the rocket to detonate the rocket HTML1. NASA got approval to extend that to 25 days, but that time is almost up. NASA will need to return to the VAB unless it gets another extension.

“We do not launch until we think it’s right,” NASA administrator Bill Nelson said during a press conference. “So I look at this as part of our space program, of which safety is at the top of our list.”

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