The crew of the Boeing CST-100 Starliner has received encouraging news regarding its return to Earth. Recent ground tests of the spacecraft’s thrusters, which have left it stranded in space since early June, have been successfully completed. Both Boeing and NASA had been awaiting the conclusion of these tests to begin organizing the vehicle’s homeward journey.
An update released late last week confirmed, “Ground testing of a Starliner Reaction Control System (RCS) thruster at White Sands Test Facility in New Mexico is complete, and teams are now turning their attention to data reviews.” The purpose of these tests was to examine thruster degradation to help engineers understand why some thrusters were inoperative during flight, as well as to assess any potential impacts of returning those thrusters to service on the Crew Flight Test.
The term “de-selected” refers to thrusters that ceased functioning. The helium tanks that control the thrusters experienced leaks both before and during the launch of the Starliner, resulting in several delays. Officials indicated last month that the spacecraft has 70 hours’ worth of helium available, despite only needing seven hours. While they mentioned earlier this month that the craft could return if necessary, they emphasized that they are not yet fully prepared for that return.
In the latest briefing, NASA and Boeing noted that a return flight could potentially happen by the end of this month. However, the timeline has now become less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and 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.”