NASA and Boeing to Proceed with Starliner Test Flight Despite Propulsion Issues

NASA and Boeing are gearing up for a June 1 launch of the CST-100 Starliner on a crewed test flight after encountering propulsion system issues. A helium leak was discovered in a reaction control system thruster, leading to the detection of a design vulnerability in the spacecraft’s propulsion system. Engineers determined that the leak was caused by a defective seal in a flange and concluded that Starliner can still fly with the leak as-is. The lack of leaks in other thrusters provided confidence that there is no systemic problem. Additionally, a design vulnerability was identified that could prevent a deorbit burn in a rare circumstance. Boeing is working on permanent fixes for the issue to be implemented in later Starliner missions.

New Deorbit Reentry Mode Developed for Starliner Following Propulsion System Review

An in-depth review of Starliner’s propulsion system revealed a design vulnerability that could impact the spacecraft’s ability to perform a deorbit burn under specific conditions. Engineers developed a new deorbit reentry mode that would utilize four RCS thrusters in the event of a failure involving adjacent «doghouses» containing thrusters. While this failure mode is considered rare, Boeing is working on hardware changes and software modifications to address the issue for future Starliner missions. The discovery of this vulnerability underscores the importance of thorough testing and review processes during spacecraft development.

Launch Preparations Continue for Starliner Test Flight Despite Propulsion Challenges

Despite encountering propulsion system issues, NASA and Boeing are moving forward with preparations for the CST-100 Starliner test flight scheduled for June 1. After a helium leak was detected in a thruster, engineers conducted a detailed review of the propulsion system, leading to the identification of a design vulnerability that could impact deorbit capabilities. Teams are working on permanent fixes for the issue, including hardware changes and software modifications. The two NASA astronauts assigned to the mission, Butch Wilmore and Suni Williams, remain in pre-flight medical quarantine in Houston, ready for their next launch opportunity. Launch preparations are ongoing, with a new flight test readiness review scheduled for May 29 ahead of the June 1 launch date.