After analyzing data following a launch scrub Monday, United Launch Alliance managers decided to haul the Atlas 5 rocket carrying Boeing’s Starliner astronaut ferry ship back to its processing facility to replace a suspect valve, delaying another launch attempt to at least May 17, NASA said in a blog post. The new launch target will give engineers more time to perform the valve repair while fitting into the U.S. Eastern Range launch schedule. The launch from Florida’s Cape Canaveral Space Force Station is now scheduled for 6:16 p.m. EDT on May 12, a week from Friday.
The Starliner, Boeing’s response to SpaceX’s Crew Dragon spacecraft, was grounded just two hours before its intended launch on its first piloted test flight to the International Space Station. NASA astronauts Barry “Butch” Wilmore and Sunita Williams were on board. The delay was caused by a pressure relief valve in the rocket’s Centaur upper stage liquid oxygen plumbing that failed to seal correctly during the final stages of propellant loading. The valve exhibited abnormal behavior, rapidly opening and closing, leading to the launch being scrubbed.
The valve in question was designed to regulate pressure by opening and closing as needed to release gaseous oxygen buildups in the Centaur’s liquid oxygen tank. It failed to seal properly and engineers reported an audible hum due to its repeated chattering during prelaunch operations. The ULA team successfully commanded the valve closed after safely egressing the ground and flight crew. However, the decision was made to replace the valve after assessing risks and determining that it exceeded its qualification. The Atlas 5 rocket will be moved back to the processing facility for the replacement before being returned to the pad for pre-launch preparations.
NASA funded the development of two crew transport crafts after the space shuttle’s retirement, awarding contracts to Boeing for its Starliner and SpaceX for its Crew Dragon. While SpaceX has successfully completed multiple crewed flights to the space station using the Crew Dragon, Boeing’s Starliner has faced technical challenges causing delays and additional costs to address issues. The launch delay of the Starliner was not related to any hardware problems with Boeing, and the program is considered separate from Boeing’s aviation operations.
The launch scrub and subsequent delay represent another setback for Boeing’s Starliner program, which has faced years of delays and technical challenges. Despite these setbacks, the Starliner remains a crucial part of NASA’s plans for crew transport to the space station. While SpaceX’s Crew Dragon has demonstrated success in safely transporting astronauts to orbit, Boeing’s Starliner aims to provide another option for crewed missions. The valve replacement and subsequent rescheduled launch will allow engineers to ensure the rocket is safe for the upcoming mission.
