The Boeing CST-100 Starliner crew has received encouraging news regarding their return journey to Earth. Recent ground tests on the spacecraft’s thrusters, which have left it stranded in orbit since early June, have been completed. Both Boeing and NASA were awaiting the completion of these tests before planning the Starliner’s return.
An update shared last week announced, “Ground testing of a Starliner Reaction Control System (RCS) thruster at White Sands Test Facility in New Mexico is complete, and teams are now focusing on data reviews.” The primary goal of the tests was to assess any degradation of the thrusters to understand why some had failed during the flight and to evaluate the implications of reactivating those thrusters for the upcoming Crew Flight Test.
The term “de-selected” refers to the thrusters that ceased functioning. Prior to and during the Starliner launch, leaks were detected in the helium tanks that supply the thrusters, causing several delays. Officials noted that the spacecraft contains 70 hours’ worth of helium, even though only seven hours are necessary for its operations. While they indicated earlier this month that the Starliner could return immediately if necessary, they also expressed that it is not yet fully prepared for re-entry.
In the latest updates, NASA and Boeing suggested that a return flight might be possible towards the end of this month. However, the timeframe has since become less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections and will continue finalizing flight rationale to support readiness reviews for Starliner’s scheduled return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”