First crewed flight of the Boeing Starliner scrubbed once again

Once again, the planned crewed launch of the Boeing Starliner has been called off at the last minute. The launch today was scrubbed at 3 minutes and 50 seconds before liftoff due to a problem with the ground system. This is the second time that the first crewed mission using the Starliner has been called off shortly before launch, with a previous attempt on May 6 called off due to a different issue with the rocket.

Since the May scrub, further issues with the Starliner including a helium leak have come to light, leading to today’s planned launch being pushed back several times. However, these previous issues were not the cause of the scrub today, said Steve Stich, manager of NASA’s Commercial Crew Program, in a post-launch attempt briefing.

“We got inside four minutes and then we had a problem with the ground launch sequencer,” said Stich.

There were two incidents with the ground system, firstly with a set of valves that did not open correctly. These are triple redundant, said Tony Bruno, president and CEO of United Launch Alliance, assuring that the crew were in no danger from the issues. The second issue was with the ground launch system, which works to release the rocket at it lifts off. This is also triple redundant, requiring all three computer systems to be running for a launch — and one of these systems was delayed in giving the okay to a health check. That means the launch was automatically scrubbed.

“What will happen next is to gain physical access to that computer and determine why that occurred,” Bruno said, which will have to wait until the rocket is defueled. The engineers should be able to look at the issue within the next few hours and if the fix is a simple one, then the launch could go ahead tomorrow. If it turns out to be more complicated, however, the launch could be delayed even further. There are backup launch dates available on Wednesday June 5 and Thursday June 6 as well as the one tomorrow, Sunday June 2.

The aim is for the Boeing Starliner to join the SpaceX Dragon as an option for transporting astronauts from Earth to the International Space Station and back. Since the shuttering of the Space Shuttle, NASA relied on Russian spacecraft for transporting astronauts for years until the SpaceX Dragon made its crewed test flight in 2020. Now, NASA wants to not be depend on one single company for its transportation needs.

“We really would like to have, and need, two redundant space transportation systems. It’s really important for us to have that,” Stich said. He also emphasized that the launch today was very close to going off: “The vehicles were ready, we were just unlucky to have a ground card problem. “