The crew of the Boeing CST-100 Starliner has received encouraging news regarding its eventual return to Earth. Recent ground tests of the spacecraft’s thrusters, which have prevented it from returning since early June, have been successfully completed. Boeing and NASA were waiting for these tests to finalize the plans for the spacecraft’s homecoming.
An update released last week stated, “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 testing was to analyze thruster performance and understand the issues that caused some thrusters to fail during flight, as well as to assess any potential risks of returning these thrusters to operation for the remainder of the Crew Flight Test.
The term “de-selected” refers to some thrusters that malfunctioned. Prior to and during the Starliner launch, leaks were detected in the helium tanks that control the thrusters, which resulted in several delays. During a press conference last month, officials indicated that the spacecraft has 70 hours’ worth of helium onboard, significantly more than the seven hours it requires. Although they suggested earlier this month that the craft could return immediately if necessary, they clarified that they are not fully prepared for that yet.
The latest update from NASA and Boeing indicated that a return flight could potentially happen by the end of this month. However, the timeline has shifted to a more open-ended approach: “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.”