The Boeing CST-100 Starliner crew has received some positive news regarding their spacecraft’s return to Earth. Recent ground tests of the spacecraft’s thrusters, which have kept it in orbit since early June, have been completed. Boeing and NASA had been awaiting these tests to initiate plans for the Starliner’s re-entry.
An update from late last week confirmed, “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 testing aimed to assess thruster degradation and to understand the issues that led to some thrusters being de-selected during flight, as well as the potential impact of returning those thrusters to service on the overall Crew Flight Test.
The term “de-selected” refers to thrusters that malfunctioned. The helium tanks, which control the thrusters, had been leaking prior to and during the Starliner’s launch, causing several delays. Officials noted last month that the spacecraft contains 70 hours’ worth of helium, despite only requiring seven. While it was stated earlier this month that the craft could return if necessary, officials indicated that they are not fully prepared for that eventuality.
In their latest update, NASA and Boeing mentioned that a return flight could occur at 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 advance towards 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 upcoming weeks.”