Two of Starliner's valves have been removed and sent to the Marshall Space Flight Center in Alabama for further analysis, per what was reported in a media briefing between Boeing and NASA:https://arstechnica.com/science/2021/10 ... f-of-2022/
NASA and Boeing officials said Tuesday that they have successfully removed two valves from the Starliner spacecraft and have shipped them to Marshall Space Flight Center in Alabama for further analysis.
The forensic examination—the two valves will be inspected with a variety of techniques, including a CT scan—is part of Boeing's ongoing effort to diagnose the "stuck" valve issue that caused an abort of Starliner's uncrewed test flight on August 3. With less than five hours remaining in the countdown to launch, during a routine procedure, 13 of the 24 valves that control the flow of dinitrogen tetroxide oxidizer through the service module of the spacecraft would not cycle between closed and open.
Boeing's chief engineer has already indicating what is the leading hypothesis on why the valves won't work; at some point during the 46-day period when the vehicle was fueled—and when the valves were found to be stuck—humidity must have gotten into the spacecraft. The moisture combined with the oxidizer and created nitric acid, which is highly corrosive, and likely caused a failure in the valves, causing them to get stuck.
Boeing and NASA are targeting an early 2022 launch for Starliner's second flight test, with the earliest possible crewed test sometime in either late 2022, or early 2023. In the meantime, NASA has already moved to negotiate with SpaceX for additional crewed Dragon missions to the ISS in case SpaceX completes their contracted 6 missions before Starliner even gets off the ground.