The crew of the Boeing CST-100 Starliner received encouraging news regarding their return to Earth. Recent ground tests of the spacecraft’s thrusters, which have left it orbiting since early June, have now been finalized. Boeing and NASA were waiting for these tests to determine the timeline for the spacecraft’s return.
An update from last week indicated, “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 focus to data reviews.” The tests aimed to assess thruster performance following reports of some thrusters being “de-selected” in-flight, allowing teams to better understand the issues leading to these malfunctions and evaluate the process for reactivating them.
The term “de-selected” refers to the thrusters ceasing to function. Prior to and during the Starliner’s launch, the helium tanks that control the thrusters were found to be leaking, resulting in several delays. Officials indicated that the spacecraft carries 70 hours’ worth of helium, despite only requiring seven hours for operation. Earlier this month, officials mentioned that while the spacecraft could return immediately if necessary, they are not fully prepared for that scenario.
Most recently, NASA and Boeing suggested that a return flight could occur by the end of the month. However, the current timeline has become less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and continue to finalize flight rationale in preparation for readiness reviews for Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the upcoming weeks.”