The Boeing Starliner Crew Flight Test (CFT) is the first crewed flight of the CST-100 Starliner spacecraft, developed by Boeing in partnership with NASA. The mission was launched on June 5, 2024, from Cape Canaveral Space Force Station, Florida, carrying two NASA astronauts: Butch Wilmore (Commander) and Sunita “Suni” Williams (Pilot). Both the astronauts have been unable to return from the International Space Station (ISS) due to multiple technical issues with Boeing’s Starliner spacecraft. The primary concerns include:
Thruster Failures
Five of Starliner’s reaction control thrusters failed during its approach to the ISS, forcing Wilmore to take manual control of the spacecraft. Four of the five thrusters were later recovered, but this raised concerns about their reliability for re-entry to Earth.
Helium Leaks
Starliner has experienced five separate helium leaks in its propulsion system. Helium is used to pressurize the thrusters, and these leaks could potentially impact their performance. NASA was aware of one leak before launch but proceeded with the mission, believing it was manageable. However, additional leaks were discovered after reaching orbit.
Uncertainty in Thruster Performance
Engineers had to test Starliner’s thrusters while docked at the ISS to determine if they could function safely for undocking and re-entry. Tests are still ongoing, and NASA is assessing whether Starliner can safely bring the astronauts back to Earth or if another return option, such as SpaceX’s Crew Dragon, will be used.
Time Constraints and Scheduling Issues
Starliner’s return must be carefully scheduled to avoid conflicts with upcoming ISS operations, including spacewalks and the arrival of SpaceX Crew-9 in mid-August. If the issues are not resolved soon, NASA may need to move the astronauts to another vehicle.
Return plan
Initially NASA decided that astronauts Sunita Williams and Butch Wilmore will return to Earth aboard a SpaceX Crew Dragon capsule in February 2025. NASA opted to bring them back with SpaceX’s Crew-9 mission, while Starliner will return to Earth uncrewed for further testing and assessment. However, the agency is now targeting March 12 for the launch of Crew-10, which will carry three astronauts and a cosmonaut to the International Space Station (ISS).
