The Boeing CST-100 Starliner crew received some positive news regarding their return to Earth. Earth-based testing of the spacecraft’s thrusters, which have left it in orbit since early June, has been completed. Boeing and NASA were waiting for the results of these tests to begin organizing the spacecraft’s journey home.
An update from last week noted, “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 focusing on data reviews.” The aim of the tests was to analyze any degradation in the thrusters to understand why some failed during the flight and assess the implications of potentially returning those thrusters to operational status.
The term “de-selected” refers to some thrusters that stopped functioning. Prior to and during the Starliner launch, there were issues with the helium tanks that control the thrusters leaking, which caused several delays. Officials stated last month that the Starliner has 70 hours’ worth of helium on board, despite only requiring seven. Although they indicated that the spacecraft could return immediately if necessary, they clarified that they are not yet ready for that to happen.
In their most recent update, NASA and Boeing mentioned that a return flight could take place at the end of this month. However, the timeline is now less certain: “Boeing and NASA engineers will conduct thruster disassembly and inspections and proceed with finalizing flight rationale for readiness reviews concerning Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”