Boeing's Starliner spacecraft's first crewed test flight to the ISS is now set for May 17 at 6:16 p.m. EDT, following a delay due to a faulty valve.

The mission was postponed to replace a pressure regulation valve in the rocket's Centaur upper stage liquid oxygen tank.

NASA astronauts Suni Williams and Butch Wilmore are slated for an eight-day mission aboard the Starliner once the issue is resolved.

The Starliner, which can hold up to seven passengers, is designed for missions to low-Earth orbit and will transport astronauts, cargo, and scientific equipment to the ISS.

Boeing's success with Starliner is critical to compete with SpaceX's Crew Dragon and to fulfill contractual obligations of the $4.2 billion deal with NASA's Commercial Crew Program.