NASA astronauts will have to wait until at least the end of next week to launch the Boeing Starliner spacecraft into orbit. The planned launch was canceled Monday night because of a problem with the Atlas V rocket that was supposed to send them into space.
On Tuesday night, NASA announced that the two astronauts, Butch Wilmore and Sunny Williams, would remain on Earth until May 17 at the earliest. Earlier in the day, the agency said a launch later this week, perhaps on Friday, could be possible.
United Launch Alliance, the manufacturer of the Atlas V, said the rocket would be returned from the launch pad to replace a valve that regulates the pressure in the oxygen tank in the second stage.
That further delayed the first-ever crewed flight of the Starliner, NASA’s shuttle of astronauts to and from the International Space Station, which has suffered a series of costly delays over the past few years.
About three hours before the scheduled launch time of 10:34 p.m. ET, just as the astronauts arrived at the launch pad, the valve began to hum at a rate of about 40 times per second. Crews on the launch pad described hearing an “unusual sound” to the flight controllers.
Preparations for the flight continued with Mr. Wilmore and Ms. Williams aboard the spacecraft. But at 8:34 p.m. ET, two hours before liftoff, United Launch Alliance, the company that builds and operates the rocket, canceled the flight.
Tory Bruno, ULA’s CEO, said this behavior had been observed before during some other Atlas V launches, and opening and closing the valve usually stopped the buzzing.
But for astronaut launches, ULA had created a rule not to do anything that might change the state of the rocket when astronauts are present, including opening and closing a valve. This in itself was not a dangerous action, but it would still add uncertainty.
“Our philosophy is that we shouldn’t change the state of the vehicle when people are in there, so we won’t,” Mr. Bruno said at a news conference Monday night along with representatives from NASA and Boeing.
After the astronauts exited the Starliner and returned to their crew quarters, the valve was closed and the buzzing stopped. But the vibrations recurred twice when the fuel was drained from the tanks.
After reviewing the data, ULA engineers concluded that the valve had exceeded the limit for the number of times it could be reliably opened and closed and that it needed to be replaced.
Boeing was one of two companies that won a contract to build a spacecraft to carry astronauts to and from the space station several years after NASA retired its space shuttles in 2011. For nine years, astronauts could reach the International Space Station only on board the Russian Soyuz rockets.
The other company was SpaceX. In May 2020, two NASA astronauts, Bob Behnken and Doug Hurley, flew to the ISS on SpaceX’s Crew Dragon. Since then, this capsule has become the only way to reach orbit from the United States.
Developing the Starliner took Boeing much longer than expected. Technical pitfalls included inadequate software testing, corroded fuel valves, flammable tape and a key component in the parachute system that proved weaker than designed. Boeing fixed the problems and it was finally ready for launch. The delays have left Boeing facing more than $1.4 billion in unexpected fees.
While Monday’s scrubbed flight was caused by the rocket, the delayed launch attempt comes during a difficult 2024 for the space giant. Just days into the year, a Boeing 737 Max 9 fuselage panel exploded on an Alaska Airlines flight. The pilots were able to land the plane safely and there were no major injuries, but the episode had widespread implications for the company, particularly its aviation division.
Neeraj Chokshi contributed reporting.
