The Boeing CST-100 Starliner crew has received some positive news regarding their return to Earth. Recent ground testing of the spacecraft’s thrusters, which have been inactive since early June, has been completed. Boeing and NASA were waiting for these tests before they could begin planning for the spacecraft’s homebound journey.
An update released last week stated, “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 testing aimed to identify thruster degradation, allowing the teams to understand the reasons behind some thrusters being de-selected during flight and to assess any potential impacts of returning those thrusters to service for the Crew Flight Test.
The term “de-selected” refers to thrusters that ceased functioning. Prior to and during the Starliner launch, the helium tanks that control these thrusters experienced leaks, causing several delays. Officials indicated last month that the spacecraft carries 70 hours’ worth of helium onboard, despite only needing seven. While they previously mentioned that the Starliner could return immediately if necessary, they clarified that they are not fully prepared for that at this moment.
In their latest update, NASA and Boeing mentioned that a return flight could potentially occur at the end of this month. However, the timeline has since become less defined: “Boeing and NASA engineers will move forward 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 upcoming weeks.”