The crew of the Boeing CST-100 Starliner has received encouraging news regarding their return to Earth. Recently, Earth-based testing of the spacecraft’s thrusters, which have kept it in space since early June, was successfully completed. Boeing and NASA had been awaiting the outcome of these tests to initiate plans for the spacecraft’s return voyage.
Last week, an update confirmed, “Ground testing of a Starliner Reaction Control System (RCS) thruster at White Sands Test Facility in New Mexico is complete, and teams are now turning their attention to data reviews.” The purpose of this testing was to evaluate thruster degradation, allowing teams to better understand the reasons behind the in-flight failure of certain thrusters and the potential impact of reactivating them.
The term “de-selected” refers to thrusters that ceased to function. Prior to and during the Starliner launch, the helium tanks that control these thrusters experienced leaks, causing several delays. During a press conference last month, officials noted that the spacecraft has enough helium for 70 hours of operation, despite only needing seven. While they mentioned that the spacecraft could return to Earth if necessary, they indicated that they are not quite ready for it to do so.
In the last update, NASA and Boeing suggested that the return flight might take place at the end of this month. However, the timeline has since become less definitive, stating, “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.”