After agreeing to alter service modules for that mission, NASA and Boeing have rescheduled the CST-100 Starliner spacecraft’s second uncrewed test flight until May 2022. The service module designed for the CFT (Crew Flight Test) mission, which would test the vehicle’s ability to transport people, will now be utilized for the OFT (Orbital Flight Test) 2 mission, according to the amended plan. Instead, the CFT mission will use the Starliner-1 service module for its first operational flight.
The OFT-2 mission could deploy in the spring as a result of this strategy. Boeing will collaborate with the Eastern Range and United Launch Alliance (ULA), whose Atlas 5 is going to launch the spacecraft, to evaluate a launch date in May. The exact timing will be determined by the spacecraft’s readiness as well as the itinerary of other vehicles accessing the International Space Station.
“Our goal was to return to flight as quickly as possible and safely. With this goal in mind, we embarked on two separate paths: repairing valves to preserve the alternative of using the existing service module (SM2) while also working to speed up the development of the next service module (SM4),” said John Vollmer, who serves as the vice president as well as program manager for Boeing’s commercial crew program, in a statement released on December 13. “We’ve opted to fly SM4 next and undertake longer-term experiments with SM2 hardware, that is on the vehicle and also in offline facilities, based on the findings thus far.”
The OFT-2 mission was canceled in August after valves in the service module’s propulsion system failed to open. The focus of the work was on a nitrogen tetroxide oxidizer that pierced Teflon seals in valves and reacted with the moisture on the other side. As a result, nitric acid was produced, which corroded the seals and led them to remain closed.
The actual nature of the problem, which was not seen on the initial OFT flight in December 2019, as well as how to remedy it, remains unknown. NASA said in a statement that “ongoing investigative attempts continue to verify the most probable reason to be linked to oxidizer and moisture interactions,” but didn’t go into detail about the source of the moisture or how to fix the problem.
NASA and Boeing stated they were working on “preventative remediation actions” for the OFT-2 mission’s new service module. Before moving through with preparations to replace the service modules, engineers checked the module to ensure it was in good working order.
NASA’s commercial crew program manager, Steve Stich, said in a release that the agency, as well as Boeing, have been cooperating to examine the issue, which has included tests at NASA sites. “As a result of the combined study, we now have a much better knowledge of the contributors to the valve issues, as well as measures to avoid it from happening again,” he said.