The Boeing CST-100 Starliner crew received positive news regarding their return home. Earth-based testing of the spacecraft’s thrusters, which have left it orbiting since early June, has recently concluded. Boeing and NASA were awaiting these test results to begin planning the spacecraft’s return.
A statement released 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 focusing on data reviews.” The objective of these tests was to assess thruster performance and understand the issues that led to some thrusters being deactivated during flight, as well as the potential impacts of bringing those thrusters back into service.
The term “de-selected” refers to thrusters that became non-functional. Prior to and during the Starliner launch, leaks were detected in tanks that hold helium used to control the thrusters, causing several delays. Officials noted that the spacecraft is equipped with 70 hours of helium, far exceeding the seven hours needed for its operations. Although they stated earlier that the craft could return immediately if necessary, they also mentioned that they are not fully prepared for that eventuality.
In their last update, NASA and Boeing suggested a possible return flight at the end of this month. However, the time frame has since become less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections and continue preparing for readiness reviews for Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the weeks ahead.”