The team behind the Boeing CST-100 Starliner has received encouraging news regarding the spacecraft’s return to Earth. Recent completion of ground testing for the spacecraft’s thrusters, which have been stranded in space since early June, marks a significant step forward. Boeing and NASA had been awaiting these test results to initiate planning for the Starliner’s homeward journey.
An update from 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 focusing on data reviews.” The objective of the testing was to analyze thruster performance degradation, allowing teams to understand why some thrusters were disabled during flight and to assess the implications of potentially reactivating them for the upcoming Crew Flight Test.
The term “de-selected” indicates that some thrusters stopped functioning as intended. Prior to and during the launch, the helium tanks that manage the thruster operations were found to be leaking, causing multiple delays. Officials noted last month that the spacecraft is equipped with 70 hours’ worth of helium, despite only requiring seven for its operations. Although they mentioned earlier this month that the vessel could return immediately if necessary, they clarified that it is not yet prepared for re-entry.
In their most recent update, NASA and Boeing suggested that a return flight could occur by the end of this month. However, this timeframe is now less certain: “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.”