The computer controlling the countdown on the Atlas V rocket triggered an automatic shutdown less than four minutes before the launch of Boeing Co’s Starliner commercial spacecraft on Saturday, keeping the crewed test flight grounded for at least a few more days.
NASA astronauts Butch Wilmore and Suni Williams were already aboard the spacecraft when a computer glitch on the ground halted the countdown. “Wait. Wait. Wait,” a member of the Atlas V launch team yelled over the phone.
The outage caused the mission to miss an immediate launch opportunity at 12:25 pm EDT (16:25 UTC), and late Saturday NASA announced the team was abandoning Sunday’s launch opportunity. The next opportunity to put Starliner into orbit will be on Wednesday at 10:52 am EDT (14:52 UTC). The mission has one launch opportunity every one to two days, whenever the International Space Station’s orbit returns to a suitable position with the launch pad of its Atlas V rocket in Florida.
Wilmore and Williams will be aboard the Starliner spacecraft on the first crewed flight to low Earth orbit. The capsule will dock with the International Space Station about a day after launch and stay there for at least a week before parachuting down at one of two landing sites in New Mexico or Arizona. Once operational, Boeing’s Starliner will join SpaceX’s Crew Dragon capsule, giving NASA two independent crewed spacecraft to transport astronauts to the space station.
The Starliner spacecraft has come a long way to get to this point, and there’s still a lot of work to be done before the capsule can take off on its long-delayed first flight with astronauts aboard.
Engineers from United Launch Alliance, manufacturer of the Atlas V rocket, are scheduled to begin troubleshooting the computer glitch on the launch pad Saturday evening after fuel is drained from the launch vehicle. Early indications suggest that a card in one of the three computers managing the final minutes of the Atlas V countdown failed to start up sooner than expected.
“Imagine that big rack as a big computer, and the controller functions of that computer are split up onto separate cards or printed wiring boards with logic devices on them,” said Tory Bruno, ULA’s president and CEO. “They’re all independent, but together they become a unified controller.”
The computers are located on the launch pad in a shelter near the base of the Atlas V rocket at Cape Canaveral Space Force Station. All three computers must be fully functional during the final stages of the countdown to ensure triple redundancy. At the moment of liftoff, these computers control things like retracting the umbilical lines and releasing the bolts that secure the rocket to the mobile launch pad, ensuring the safety of the rocket.
As the final countdown began with four minutes left, two of the computers started up. It took another six seconds or so for a card in a third computer to come online, but it eventually did, Bruno said.
“Two of them rose normally and the third rose but it rose slowly, which was a red flag,” he said.
Disappointment
Wilmore and Williams, both veteran astronauts and former U.S. Navy test pilots, escaped the Starliner spacecraft with the help of a Boeing ground team and returned to NASA’s crew quarters at nearby Kennedy Space Center to await the next launch.
The schedule for the next launch will depend on what ULA workers find when they access the launchpad’s computers. Officials initially said the countdown to the next launch could begin early Sunday if they could find a simple solution to the computer problems, such as replacing a faulty card. Though the computers are networked together, the architecture is designed with interchangeable cards, each responsible for a different function during the countdown, allowing for quick fixes without replacing the entire unit, Bruno said.
NASA announced later in the day that the launch would not take place on Sunday to give teams additional time to evaluate the computer issues, with the next launches scheduled for Wednesday and Thursday.
Bruno said ULA engineers believe the computer problems during Saturday’s countdown were due to a hardware issue or a glitch in network communications. ULA’s troubleshooting team worked overnight to determine the cause. NASA said officials would provide another update on Sunday.
If it doesn’t launch by Thursday, the Starliner test flight could be delayed further to give ULA time to replace the Atlas V rocket’s short-lived batteries, which Bruno said will take about 10 days.
The aborted countdown on Saturday was the latest in a series of delays for Boeing’s Starliner program. The spacecraft’s first crewed test flight is seven years behind the schedule Boeing announced when NASA awarded the company a $4.2 billion contract for the crewed capsule in 2014. In other words, this moment comes nine years after Boeing first said the spacecraft was operational when the program was first announced in 2010.
“Obviously, it’s an emotional disappointment,” said Mike Fink, a NASA astronaut who backed up Wilmore and Williams on the crew test flight, “and I know that Butch and Suni didn’t look disappointed when they heard it on the loop, because it’s a matter of professionalism.”
NASA and Boeing were on the verge of launching a Starliner test flight on May 6, but officials halted the launch due to a problem with a valve on the Atlas V rocket. Engineers later discovered a helium leak in the Starliner spacecraft’s service module, but managers agreed to go ahead with Saturday’s launch if the leak didn’t worsen during the countdown.
A check of the helium system on Saturday morning revealed that the leak rate had decreased since the last measurement and was no longer a constraint on launch, but it did raise other issues for keeping Starliner on Earth.
“Everybody’s a little disappointed, but we just have to roll up our sleeves and get back to work right away,” said Steve Stich, NASA’s Commercial Crew Program manager.
