The crew of the Boeing CST-100 Starliner has received encouraging news regarding its return to Earth. Earth-based tests of the spacecraft’s thrusters, which have left it stranded in space since early June, have recently concluded. Boeing and NASA were awaiting the completion of these tests to start planning for the spacecraft’s homeward journey.
An update released last week stated, “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 testing was to analyze thruster degradation to understand why some thrusters were deactivated during the flight and to assess any potential impact on the remainder of the Crew Flight Test when returning those thrusters to service.
The term “de-selected” refers to the thrusters that ceased functioning. Prior to and during the Starliner launch, the helium tanks that control the thrusters experienced leaks, causing numerous delays. Officials reported last month that the spacecraft carries 70 hours’ worth of helium despite only needing seven. Although they indicated earlier this month that the craft could return immediately if required, they clarified that they are not yet fully prepared for its return.
In the most recent update, NASA and Boeing suggested a return flight could happen at the end of this month. However, the timeline is now more uncertain: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and continue to finalize 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.”