Boeing Starliner spacecraft launch scrubbed minutes before liftoff

In a briefing shortly after the mission was waived off Saturday, ULA chief executive Tory Bruno said that one of the three computer systems that orchestrate the launch sequence in the final minutes of the countdown — by releasing clamps that hold down the rocket, for example — was slow to come online. As a result, the automated system triggered an end to the countdown. ULA is a joint venture between Boeing and Lockheed Martin.

Boeing has been eager to get the mission off the ground. It would send NASA astronauts Sunita Williams and Butch Wilmore to the International Space Station for about a week to test out how the spacecraft operates with humans on board.

“I know it’s a little disappointing,” Steve Stich, who heads NASA’s commercial crew program, said of the delay. “We were all excited, and Butch and Suni were excited to go fly. This is kind of the way spaceflight is … Every time you go to the pad for crewed flight or really any flight, you’ve got a chance to scrubbing.”

He added that, “you can see today how close we are. We are really close to having this capability ready to go. We were three minutes and 50 seconds away, with a Starliner spacecraft that was ready to go.”

Given the fact that the spacecraft has never flown with people on board, the teams from NASA and Boeing have said repeatedly that they would proceed with caution and would not attempt to fly the mission until they felt they could do so safely.

The flight test with a crew on board was initially scheduled for May 6. But that flight was delayed because of a malfunctioning valve on the second stage of the rocket. The valve has since been replaced and officials said it was functioning well on Saturday.

The launch is part of NASA’s “commercial crew program,” which outsourced transportation to the space station to Boeing and SpaceX.

SpaceX has become the dominant commercial rocket and spacecraft manufacturer; it flew astronauts first, completing its first crewed test mission in May 2020. That flight was a major coup for NASA because it gave it a way to get its crews to space. In 2011, the space shuttle was retired, forcing NASA to rely on Russia to fly people to the station until SpaceX started flying.

Boeing’s Starliner has faced setbacks and delays. It had to fly two test flights without crew on board, instead of one as had been anticipated. The first, in late 2019, was cut short because the rocket’s onboard computer was off by 11 hours and the spacecraft never reached the station. It reached the space station on the next try, in 2022. However, the company discovered afterward that tape used to cover electrical wiring in the capsule was flammable and that its parachutes needed an upgrade.

Leading up to Saturday’s flight, Boeing and NASA officials expressed confidence, saying they had done everything they could to ensure the mission would be successful.