NASA, Boeing Prepare To Replace Starliner Service Modules Ahead of Mission to Space Station

Boeing Starliner. Credit: Boeing

NASA and Boeing continue making progress toward the agency’s upcoming Starliner Orbital Flight Test-2 (OFT-2) mission to the International Space Station as part of NASA’s Commercial Crew Program.

Teams recently completed offloading fuel from the OFT-2 spacecraft inside Starliner’s production factory at NASA’s Kennedy Space Center in Florida in preparation for separating and replacing the current service module (SM2) from the crew module.

“The Starliner team and successful completion of the spacecraft’s development phase are critical to sustaining International Space Station operations through 2030,” said Steve Stich, manager, NASA Commercial Crew Program. “The team’s dedication to developing effective remedies and corrective action after our first OFT-2 launch attempt demonstrates their continued commitment to safely flying NASA crews for years to come.”

Starliner technicians work on the Orbital Flight Test-2 spacecraft in the high bay of Boeing’s Commercial Crew and Cargo Processing Facility at NASA’s Kennedy Space Center in Florida on January 13, 2022. Credit: NASA

In December, Boeing decided to move up service modules currently in production for its upcoming uncrewed and crewed flight tests. The service module originally planned for the Crew Flight Test (CFT) is now being used for OFT-2, and the service module originally planned for Starliner’s first post-certification mission, Starliner-1, now will be used for CFT.

With fuel offload complete, the spacecraft was moved out of the hazardous processing area and into the production factory high bay.

“Because this is not an operation that we normally perform, our team took the time to fully coordinate and assess the proper spacecraft and ground support equipment configurations, and then execute to plan to ensure the safety of our team,” said John Vollmer, vice president and program manager, Boeing’s Commercial Crew Program.

Once separated in the coming weeks from the OFT-2 crew module, SM2 will be sent to NASA’s White Sands Test Facility in New Mexico for additional testing related to the issue affecting the spacecraft’s oxidizer isolation valves.

This artist’s concept shows Boeing’s CST-100 Starliner spacecraft, docking to the International Space Station. Credit: NASA

The investigation into the valve issue continues to substantiate that the most probable cause is interaction of moisture with nitrogen tetroxide that permeates through the Teflon seal in the valve, leading to corrosion. Testing continues to fully understand how this occurrence affects the valves in various environments.

Tests include environmental seal evaluation and exposing valves, in a controlled setting, to temperatures and conditions similar to those the spacecraft experienced prior to the planned launch of OFT-2. The results of these tests will help in the ongoing development of remediation efforts to prevent similar issues on future service modules.

For example, the team designed a purging system that will be integrated into the spacecraft to protect the valves from potential exposure to moisture at the factory, launch complex, and launch pad.

Progress also continues with production of the new service module (SM4) that will go onto the OFT-2 crew module. That service module was recently moved from the low bay production area to the factory’s hazardous processing area for high pressure leak testing. Remaining tasks before mating this service module with the OFT-2 crew module include acceptance testing, final wire harness mating, installation of solar array panels, and final closeouts.

NASA and Boeing continue to work toward an opening in United Launch Alliance’s launch window availability in May for OFT-2. An actual launch date will be determined closer to spacecraft readiness, and with consideration of Eastern Range and International Space Station availability. Potential launch windows for CFT are under review and will be determined after a safe and successful OFT-2.