The Boeing CST-100 Starliner crew is receiving positive updates regarding their return to Earth. Recent ground tests of the spacecraft’s thrusters, which have left it in orbit since early June, have now been completed. Both Boeing and NASA were waiting for these tests to conclude before they could start planning the spacecraft’s journey back.
An update from late 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 turning their attention to data reviews.” The goal of these tests was to investigate thruster performance issues that caused some units to stop functioning during flight and to assess the potential impacts of returning those thrusters to service on the overall Crew Flight Test.
Some thrusters had been “de-selected,” indicating that they malfunctioned. The helium tanks that control these thrusters experienced leaks both before and during the launch, which resulted in several delays. Despite having 70 hours’ worth of helium onboard—well above the 7 hours required—officials stated last month that while the Starliner could technically return to Earth now, they are not yet prepared for that to happen.
At the latest update, NASA and Boeing suggested that the return flight could occur at the end of this month. However, the timeline is now 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.”