The highly anticipated first crewed test flight of Boeing’s CST-100 Starliner spacecraft has been postponed until at least Friday, May 10, 2024, after a technical issue was discovered just hours before the planned launch on Monday evening.
Valve Problem Detected During Countdown
The launch was scrubbed about two hours before the scheduled liftoff time when engineers detected a problem with a valve in the propulsion system of the United Launch Alliance (ULA) Atlas V rocket that will carry Starliner into orbit. Specifically, the issue was with a pressure regulation valve in the liquid oxygen tank of the rocket’s Centaur upper stage.
According to ULA, the valve was “cycling open and closed repeatedly” during the countdown, prompting mission managers to halt the launch out of an abundance of caution. Teams are now working to troubleshoot the problem and determine if the valve needs to be replaced before another launch attempt can be made.
Crew Safely Exits Spacecraft
NASA astronauts Butch Wilmore and Suni Williams, who will fly the Crew Flight Test (CFT) mission, were already strapped into their seats aboard Starliner when the launch was called off. They safely exited the spacecraft and returned to their crew quarters to await a new launch date.
Wilmore, a veteran of two previous spaceflights, will command the mission, while Williams, who has also flown twice before, will serve as pilot. The duo arrived at Kennedy Space Center in Florida last week to begin final preparations for their flight.
Starliner’s Troubled Development
The valve issue is the latest in a series of setbacks for Boeing’s Starliner program, which is years behind schedule and well over budget. The spacecraft was developed under a $4.2 billion contract with NASA’s Commercial Crew Program, which also funded SpaceX’s Crew Dragon capsule.
Starliner’s first uncrewed Orbital Flight Test (OFT) in December 2019 encountered serious software problems that prevented it from reaching the International Space Station (ISS) as planned. After an extensive investigation and corrective actions, Boeing flew a second OFT mission in May 2022 that successfully docked with the ISS.
The CFT mission will be Starliner’s final test flight before it can be certified by NASA for operational crew rotation missions to the ISS. If all goes well, Wilmore and Williams will spend about a week living and working aboard the orbiting laboratory before returning to Earth for a land-based landing in the western United States.
Next Launch Attempt No Earlier Than Friday
NASA and Boeing are now targeting no earlier than 6:54 p.m. EDT (2254 GMT) on Friday, May 10, for the next Starliner launch attempt. A backup opportunity is available on Saturday, May 11, if needed. The exact launch date and time will depend on how quickly the valve issue can be resolved and the rocket cleared for flight.
Despite the disappointment of Monday’s scrub, NASA and Boeing remain optimistic about Starliner’s future and its role in ensuring redundant access to the ISS for American astronauts. Once operational, it will provide a second domestic option alongside SpaceX’s Crew Dragon for transporting crews to and from the orbiting outpost.
However, with SpaceX having now flown seven operational crew missions for NASA since 2020, and an eighth currently in progress, Starliner has a lot of catching up to do to establish itself as a reliable and cost-effective spacecraft. Boeing will be keen to put its troubled development behind it and prove that Starliner was worth the long wait.
