The Boeing CST-100 Starliner crew has received encouraging news regarding their return to Earth. Recently, the ground testing of the spacecraft’s thrusters, which have left it stranded in orbit since early June, has been successfully completed. Boeing and NASA were awaiting these tests to begin preparations for the spacecraft’s journey home.
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 goal of the tests was to assess thruster degradation to better understand why some thrusters became inoperable during the flight, as well as to evaluate the implications of restoring those thrusters for the overall Crew Flight Test.
The term “de-selected” refers to thrusters that ceased functioning. Prior to and during the Starliner launch, tanks containing helium that control the thrusters experienced leaks, which led to several delays. At a press conference last month, officials noted that the spacecraft holds 70 hours’ worth of helium, despite only needing seven. Although they indicated earlier this month that the craft could return immediately if necessary, they emphasized that they are not fully prepared for a return just yet.
In the latest update, NASA and Boeing mentioned that a return flight could potentially happen by the end of this month. However, this timeframe has become less precise: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and continue finalizing flight rationale in preparation for readiness reviews for Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”