The Boeing CST-100 Starliner crew received positive news regarding their return home. Recently, ground tests of the spacecraft’s thrusters wrapped up, which have kept it in orbit since early June. Both Boeing and NASA were awaiting these tests to start planning the spacecraft’s return.
An update from last week noted, “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 tests aimed to assess thruster performance issues to better understand why some thrusters were undelivered during the flight and how their return might affect the ongoing Crew Flight Test.
The term “deselected” refers to thrusters that became inoperative. Prior to and during the Starliner’s launch, the helium tanks used to control the thrusters experienced leaks, resulting in multiple delays. At a press conference last month, officials mentioned that the spacecraft carries 70 hours’ worth of helium, despite only needing seven for its operations. While they indicated that the Starliner could return immediately if necessary, they also emphasized that preparations were not yet complete.
In their last update, NASA and Boeing suggested a potential return by the end of this month. However, the timeline has become less certain: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and advance towards finalizing flight rationale in support of readiness reviews for Starliner’s routine return to Earth with commander Butch Wilmore and pilot Suni Williams in the upcoming weeks.”