Boeing's Starliner finds yet another way to not reach space

Boeing's Starliner has failed to launch once again, this time due to a faulty power supply in a ground computer chassis.

Unreliable power supplies are the bane of many an administrator, and it appears that the space program is not immune to their vagaries.

The launch, from Space Launch Complex 41 (SLC-41) at Cape Canaveral Space Force Station in Florida, was scheduled for 12:25 EDT on June 1. It made it past the T-4 minute mark before controllers called a scrub and returned the crew access arm to the capsule to extract the pair of astronauts on board.

At the time, the issue was attributed to "the computer ground launch sequencer not loading into the correct operational configuration after proceeding into terminal count," and managers optimistically looked to the backup date of June 2.

However, it soon became apparent that more time was needed to deal with whatever had gone wrong this time round. NASA, Boeing, and ULA (United Launch Alliance) opted to forgo the June 2 opportunity in favor of June 5. There is one final opportunity, on June 6, after which batteries onboard the Atlas will require replacing.

The trouble was caused by a single ground power supply within one of three redundant chassis. This supply provides power to computer cards that control various system functions, "including the card responsible for the stable replenishment topping valves for the Centaur upper stage."

Boeing said: "All three of these chassis are required to enter the terminal phase of the launch countdown to ensure crew safety."

There had been issues with the topping valves on the ground side during the count, according to ULA boss Tory Bruno, although those appear to have been resolved.

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Bruno later confirmed that the chassis had been replaced over the weekend, and the team was ready to try again on Wednesday.

It's starting to get a little tight for launching the Starliner, which has remained resolutely stuck on the Earth despite engineers' best efforts. Failure to launch by the backup date of June 6 will result in a delay of at least ten days to replace expiring batteries.

This would take the schedule very close to a planned US Space Force launch, which also requires the SLC-41 launch site.

"There's lots of pressure to just go," Bruno acknowledged, adding: "That's not what we are here for."

Ensuring the Starliner's crew has a safe trip to the International Space Station is of paramount importance. Bruno lamented that the power supply had sailed through testing and that this was the first power supply failure the team had experienced. The redundant power supply did not activate.

In words that will feel all too familiar to anyone charged with keeping a rack of servers running, he said: "Unfortunately a power supply generally does not fail... until it does." ®