The crew of the Boeing CST-100 Starliner has received encouraging news regarding their return to Earth. Earth-based testing of the spacecraft’s thrusters, which have kept it in orbit since early June, has recently concluded. Boeing and NASA were awaiting the results of these tests to start planning the spacecraft’s homeward journey.
In an update shared late last week, it was reported that “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 primary aim of the tests was to assess thruster degradation to understand the issues leading to the in-flight failure of some thrusters, and to determine the potential effects of reactivating those thrusters on the overall Crew Flight Test.
The term “de-selected” refers to thrusters that failed to function. Prior to and during the Starliner launch, leaks were detected in the helium tanks that regulate the thrusters, causing several delays. Officials indicated last month that the spacecraft has 70 hours of helium onboard, far exceeding its seven-hour requirement. While they mentioned earlier this month that the craft could return if necessary, they also clarified that they are not fully prepared for its return at this moment.
The latest information from 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.”