The crew of the Boeing CST-100 Starliner has received encouraging news regarding its anticipated return to Earth. Recent tests of the spacecraft’s thrusters, which have left it adrift in space since early June, have been successfully completed. Boeing and NASA had been awaiting the conclusion of these tests to begin organizing the spacecraft’s homeward journey.
An update released last week confirmed, “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 primary aim of these tests was to evaluate thruster degradation, providing teams with insights into why some thrusters experienced issues in-flight and what effect, if any, returning those thrusters to service would have on the overall Crew Flight Test.
The term “de-selected” refers to thrusters that ceased functioning during the mission. Helium tanks necessary for controlling the thrusters had experienced leaks both before and during the Starliner launch, which led to several delays. At a press conference last month, officials revealed that the spacecraft holds 70 hours of helium onboard, although it requires only seven for its operations. While they previously stated that the Starliner could return home immediately if necessary, they indicated that they are not fully prepared for that eventuality just yet.
The latest update from NASA and Boeing suggested a possible return flight at the end of this month. However, the timeframe has now become less defined: “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.”