Editor’s note: This blog was updated Oct. 8 to reflect that the team is working toward launch opportunities in the first half of 2022 for Orbital Flight Test-2.
The NASA, Boeing team continues to make progress on the investigation of the oxidizer isolation valve issue on the Starliner service module propulsion system that was discovered ahead of the planned uncrewed Orbital Flight Test-2 (OFT-2) mission to the International Space Station in August.
“I am proud of the work our integrated teams are doing,” said Steve Stich, manager of the Commercial Crew Program at NASA’s Kennedy Space Center in Florida. “This is a complex issue involving hazardous commodities and intricate areas of the spacecraft that are not easily accessed. It has taken a methodical approach and sound engineering to effectively examine.”
Boeing has demonstrated success in valve functionality using localized heating and electrical charging techniques. Troubleshooting on the pad, at the launch complex, and inside the Starliner production factory at Kennedy Space Center has resulted in movement of all but one of the original stuck valves. That valve has not been moved intentionally to preserve forensics for direct root cause analysis.
Most items on the fault tree have been dispositioned by the team including causes related to avionics, flight software and wiring. Boeing has identified a most probable cause related to oxidizer and moisture interactions, and although some verification work remains underway, our confidence is high enough that we are commencing corrective and preventive actions. Additional spacecraft and component testing will be conducted in the coming weeks to further explore contributing factors and necessary system remediation before flight.
Boeing completed a partial disassembly of three of the affected Orbital Maneuvering and Attitude Control (OMAC) thruster valves last month and plans to remove three valves from the OFT-2 spacecraft in the coming weeks for further inspection. The team also is evaluating additional testing to repeat the initial valve failures.
Boeing has identified several paths forward depending on the outcome of the testing to ultimately resolve the issue and prevent it from happening on future flights. These options could range from minor refurbishment of the current service module components to using another service module already in production. Each option is dependent on data points the team expects to collect in the coming weeks including a timeline for safely proceeding back to the launch pad.
“Safety of the Starliner spacecraft, our employees, and our crew members is this team’s number one priority,” said John Vollmer, vice president and program manager, Boeing’s Starliner program. “We are taking the appropriate amount of time to work through the process now to set this system up for success on OFT-2 and all future Starliner missions.”
Potential launch windows for OFT-2 continue to be assessed by NASA, Boeing, United Launch Alliance, and the Eastern Range. The team currently is working toward opportunities in the first half of 2022 pending hardware readiness, the rocket manifest, and space station availability.