The Boeing CST-100 Starliner crew has received encouraging news regarding their return to Earth. Recently, ground testing of the spacecraft’s thrusters was completed, which had left the vehicle stranded in space since early June. Boeing and NASA had been awaiting the conclusion of these tests to plan the spacecraft’s journey back home.
An update released last week stated, “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 turning their attention to data reviews.” The main aim of the tests was to identify any degradation in the thrusters, providing insight into why some thrusters were deactivated during flight and understanding the implications of reactivating them for the upcoming Crew Flight Test.
The term “de-selected” refers to some thrusters ceasing to function. This issue arose due to leaks in the helium tanks that control the thrusters, causing several delays prior to and during the Starliner launch. Although the spacecraft holds 70 hours’ worth of helium—far exceeding its requirement of seven hours—officials indicated last month that while the spacecraft could return if necessary, they are not yet ready to do so.
In their latest update, NASA and Boeing mentioned that a return flight might occur by the end of this month. However, the timeline has 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.”