Boeing was forced to cancel the first manned Starliner launch to the space station

NASA and Boeing were forced to step down Attempt to launch to the International Space Station Monday due to a last-minute problem that appeared with a valve on the spacecraft's rocket.

Boeing's Starliner capsule was scheduled to lift off at 10:34 p.m. ET from Cape Canaveral Space Force Station in Florida on its first crewed test flight. NASA astronauts Barry “Butch” Wilmore and Sunita Williams They were aboard the capsule and strapped into their seats when the launch attempt was aborted, roughly two hours before the planned liftoff.

NASA announced early Tuesday that A The second attempt will not take place before Friday.

Mission controllers declared Monday's launch “clean” after discovering a valve anomaly on United Launch Alliance's Atlas V rocket, which the Starliner capsule was scheduled to take to orbit.

United Launch Alliance officials said in a post on X that the launch attempt was canceled “out of an abundance of caution for the safety of the flight and pad crew,” adding that the team needed “additional time to complete the full assessment.”

The analysis will include whether the pressure-regulating valve in the rocket's upper stage needs to be replaced, which could cause a longer delay.

A crewed Starliner flight, when it occurs, will be a crucial final test before NASA can allow Boeing to conduct routine flights to and from the space station.

Officials at NASA and Boeing said safety is critical for the spacecraft's first flight with humans on board.

The canceled launch represents another setback for Boeing, which has already dealt with years of delays and budget overruns with its Starliner program. It has fallen significantly short of SpaceX, which has been sending crewed missions to and from the space station for NASA since 2020.

SpaceX's Crew Dragon capsule and Boeing's Starliner vehicle were both developed as part of NASA's Commercial Crew Program. The initiative began more than a decade ago, after the agency's space shuttles retired, to support private companies in building new spacecraft to transport astronauts to low Earth orbit.

The first unmanned flight of the Starliner was aborted in 2019 due to software problems. Forcing mission controllers to shorten the test Before the spacecraft can attempt rendezvous and docking with the International Space Station. The second attempt was then postponed several times due to problems with the fuel valve, and Boeing was unable to carry out the attempt until 2022. A successful uncrewed flight to and from the space station.

This article was originally published on NBCNews.com