The crew of the Boeing CST-100 Starliner has received encouraging news regarding its return to Earth. Recent ground testing of the spacecraft’s thrusters, which have kept it in orbit since early June, has been completed. Boeing and NASA had been awaiting the results of these tests to start planning the spacecraft’s homecoming.
An update released last week confirmed, “Ground testing of a Starliner Reaction Control System (RCS) thruster at the White Sands Test Facility in New Mexico is complete, and teams are now turning their attention to data reviews.” The objective of the tests was to observe any degradation in the thrusters to better understand why some of them were non-operational during flight and assess the implications of possibly returning those thrusters to service.
The term “de-selected” refers to thrusters that ceased functioning. Issues arose early on, with the helium tanks controlling the thrusters experiencing leaks, causing multiple delays before and during the Starliner’s launch. Officials indicated that while the spacecraft has 70 hours of helium onboard—far more than the seven hours required—the conditions are not yet ideal for its immediate return.
NASA and Boeing previously suggested a return flight might occur by the end of this month. However, the timeline has become less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and will move forward with finalizing flight rationale in support of readiness reviews for Starliner’s nominal return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”