Boeing scrubbed its Monday launch attempt of its new Starliner spacecraft, crewed by veteran NASA astronauts Suni Williams and Butch Wilmore.

Boeing's first astronaut-crewed flight into space has been called off due to a stuck valve on the spacecraft’s rocket Monday, the United Launch Alliance announced. The Starliner Crew Flight Test, developed in collaboration with NASA's Commercial Crew Program,

NASA has scrubbed the launch of Boeing’s Starliner, which was set to send two astronauts to the International Space Station. The cited reason for the postponement was a complication with an oxygen relief valve on the solid rocket booster.

Boeing's Starliner launch tonight has been postponed "out of an abundance of caution" scarcely two hours before the historic liftoff. After years of delays and over $1 billion in cost overruns, the mission is set to be Boeing's first attempt to transport astronauts to the International Space Station.

After its latest delay, Boeing Starliner's first crewed mission to the International Space Station (ISS) now aims to launch next week. Why it matters: A successful mission is crucial for Starliner to be certified as an operational crew system by NASA and for Boeing to begin competing with SpaceX in shuttling people to the space station.

Monday's mission was scrubbed so crews can evaluate an oxygen relief valve on the Centaur upper stage, NASA TV broadcaster Megan Cruz announced.

The planned piloted launch of Boeing's long-delayed Starliner crew ferry ship was called off with less than two hours to go before liftoff.