The Boeing CST-100 Starliner crew is optimistic about their return to Earth as critical ground tests of the spacecraft’s thrusters have been completed. The thrusters had been a concern since early June when the spacecraft became stuck in space, and Boeing and NASA were awaiting the results of these tests to plan the vessel’s homecoming.
An update revealed that ground testing of the Starliner Reaction Control System (RCS) thruster at the White Sands Test Facility in New Mexico has concluded, allowing teams to focus on reviewing the data. The objective of the tests was to assess thruster performance degradation to understand why some thrusters were deactivated during flight and to evaluate the potential impact of returning them to service for the Crew Flight Test.
The term “de-selected” refers to thrusters that malfunctioned. Previous issues included leaks in the helium tanks that control the thrusters, which caused multiple delays. Despite having 70 hours’ worth of helium on board—far exceeding the seven hours needed—officials indicated that while the spacecraft is technically capable of returning, the timing is not yet right.
NASA and Boeing previously suggested a return flight could happen by the end of the month, but the timeline now appears less certain. The latest update indicates that engineers will begin disassembling and inspecting the thrusters while finalizing flight rationale to support readiness reviews for Starliner’s expected return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.