NASA and Boeing identified helium leaks and experienced issues with the spacecraft reaction control thrusters on June 6 as Starliner approached the space station. Since then, engineering teams have completed a significant amount of work, including reviewing a collection of data, conducting flight and ground testing, hosting independent reviews with agency propulsion experts, and developing various return contingency plans. The uncertainty and lack of expert concurrence does not meet the agency’s safety and performance requirements for human spaceflight, thus prompting NASA leadership to move the astronauts to the Crew-9 mission.
