The Boeing CST-100 Starliner crew received encouraging news regarding their return to Earth. Earth-based tests of the spacecraft’s thrusters, which have caused it to remain in space since early June, have recently been completed. Boeing and NASA had deferred planning for the spacecraft’s return until these tests were finalized.
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 turning their attention to data reviews.” The purpose of the tests was to examine thruster performance issues that had led to the deactivation of some thrusters during flight, as well as to assess the potential effects of reactivating them.
The term “de-selected” refers to thrusters that ceased functioning. Prior to and during the Starliner launch, tanks containing helium, which powers the thrusters, were found to be leaking, causing several delays. At a recent press conference, officials mentioned that the spacecraft has a supply of helium sufficient for 70 hours, even though only seven hours are required for the mission. While they indicated that the craft could be brought back at any time if necessary, they also noted that they are not entirely prepared for that scenario just yet.
Previously, NASA and Boeing suggested that a return flight could occur by the end of this month. However, the timeline has since become less specific: “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.”