Boeing Starliner capsule's first crewed test flight postponed

Boeing's Starliner capsule atop an Atlas V rocket stands ready for its upcoming mission at Space Launch Complex 41 at the Cape Canaveral Space Force Station, Sunday, May 5, 2024, in Cape Canaveral, Fla. (AP Photo/Terry Renna)

CAPE CANAVERAL, Fla. -

The long-awaited first crewed test flight of Boeing's new Starliner space capsule was called off for at least 24 hours over a technical issue that launch teams were unable to resolve in time for the planned Monday night lift-off.

The CST-200 Starliner's inaugural voyage carrying astronauts to the International Space Station (ISS) has been highly anticipated and much-delayed as Boeing scrambles to compete with Elon Musk's SpaceX for a greater share of lucrative NASA business.

It comes two years after the gumdrop-shaped capsule completed its first test flight to the orbital laboratory without humans aboard. The Starliner's first uncrewed flight to the ISS in 2019 ended in failure.

Its latest flight was scrubbed with less two hours left in the countdown as the capsule stood poised for blastoff from NASA's Kennedy Space Center in Florida atop an Atlas V rocket furnished by United Launch Alliance, a Boeing-Lockheed Martin joint venture.

The postponement, attributed to an issue with a valve in the rocket's second stage, was announced during a live NASA webcast. The next available launch window for the mission is Tuesday night, but no decision was immediately made for when a second liftoff attempt would be made.

The two-member crew -- NASA astronauts Barry "Butch" Wilmore, 61, and Sunita "Suni" Williams, 58 -- had been strapped into their seats aboard the spacecraft about an hour before launch activities were suspended for the night.

They will be assisted out of the capsule by technicians to await a second launch attempt.

(Reporting by Joey Roulette in Cape Canaveral, Fla., and Steve Gorman in Los Angeles; Writing by Steve Gorman; Editing by Sam Holmes, Will Dunham and Gerry Doyle)