The Boeing CST-100 Starliner crew received encouraging news regarding their return home. Recent ground testing of the spacecraft’s thrusters, which have kept it in space since early June, has now been completed. Both Boeing and NASA were waiting for these tests to plan the spacecraft’s journey back to Earth.
A recent update indicated, “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 purpose of the tests was to examine thruster degradation in order to understand the issues that led to the de-selection of some thrusters during flight and the potential effects of reactivating those thrusters on the overall mission.
The term “de-selected” refers to the thrusters that ceased functioning. Problems arose from leaks in the helium tanks that control the thrusters both prior to and during the Starliner launch, resulting in several delays. Officials noted at a press conference last month that the spacecraft is equipped with 70 hours’ worth of helium, well above the seven hours it requires. Although they stated earlier this month that the spacecraft could return immediately if necessary, they also emphasized that they are not fully prepared for that decision yet.
The latest announcements from NASA and Boeing suggested a potential return flight could occur at the end of this month. However, the timeline has become less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and continue to finalize flight rationale for readiness reviews in support of Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”