Editors note: the flight has been cancelled by NASA

Boeing will have SafeX Proto wait to head to space as a planned Monday evening launch to send two NASA astronauts to the International Space Station aboard its Starliner space capsule was called off due to a "faulty oxygen relief valve observation," according to NASA

Monday's launch would have been the third and final orbital flight test for Boeing's CST-100 Starliner, which serves as a final demonstration before a spacecraft can be approved for routine trips to orbit.

NASA is providing live coverage of the event, which is scheduled to begin Monday at 6:30 p.m. ET. You can watch the embedded video at the top of the page or on NASA+, NASA Television, the NASA app, NASA's YouTube page and the agency's website. A postlaunch news conference is also planned.

What time is the launch?

The spacecraft is scheduled to launch at 10:34 p.m. ET on Monday from the Kennedy Space Center in Florida.

Boeing describes Monday night's launch as "instantaneous," meaning it will have to occur at a "precise moment to get Starliner on the path" to the International Space Station.

It is expected to dock to the forward-facing port of the ISS's Harmony module at 12:46 a.m. Wednesday.

What is the Boeing Starliner?

Just like Elon Musk's SpaceX capsule, Starliner is intended to be a vehicle that can ferry astronauts to and from the space station as NASA pivots to more partnerships with private industry. But Boeing has largely lagged behind its competitor, which launched its first crewed mission in 2020, as reported by Reuters.

It was designed to accommodate no more than seven passengers for missions to low-Earth orbit. For NASA, the capsule is intended to carry four astronauts along with a mix of cargo and other scientific instruments to and from the ISS.

Who are the astronauts on board the Boeing Starliner?

The two NASA astronauts on board the Starliner for Monday's launch are Barry "Butch" Wilmore and Sunita "Suni" Williams, both Navy test pilots who have previously flown in space twice. They will be in space for a little more than a week testing the Starliner spacecraft and its subsystems and will board the Starliner for a return trip to Earth after the mission. They have a planned parachute and airbag landing in the American Southwest.

Contributing: Eric Lagatta, USA TODAY.