Test Flight of Boeing’s Starliner Spacecraft Delayed Over Valve Troubles

A test flight of Boeing’s CST-100 Starliner reusable crew capsule will be delayed for several months to give engineers time fix a problem with the spacecraft’s valves, the vehicle’s manufacturer said. According to Boeing, the spacecraft, which was scheduled to launch earlier in August, will be detached from its Atlas 5 rocket and sent back to the company’s facility at the Kennedy Space Center for additional work, SpaceNews reported.

Kathy Lueders, NASA’s associate administrator for human exploration and operations, on Friday expressed disappointment over the setback as she made assurances that the team in charge of the project will quickly work towards making the vehicle flight-ready. The initial launch attempt, which was set for Aug. 3, was scrubbed after technicians discovered that 13 valves in the spacecraft’s propulsion system unexpectedly closed.

Unable to resolve the problem, technicians rolled the spacecraft back to United Launch Alliance’s Vertical Integration Facility for better access to the vehicle’s internals. As of Aug. 12, Boeing said it had fixed nine of the 13 valves, saying electrical and thermal techniques were applied to open them. Four other valves remained closed and were still being repaired.

John Vollmer, vice president and program manager of Boeing’s commercial crew program, told reporters that the cause of the problem is that nitrogen tetroxide, the oxidizer used for Starliner’s thrusters, permeated Teflon seals in the valves. He explained that the problems with the first nine valves were addressed quickly but the remaining four valves could not be fixed while Starliner was still attached to the Atlas 5 rocket.

Vollmer assured that a painstaking effort will be undertaken to study the valve problem, including determining what portions of the spacecraft need to be disassembled to correct the problem.