The Boeing CST-100 Starliner crew recently received encouraging news regarding their planned return to Earth. Recent testing of the spacecraft’s thrusters, which have left it in orbit since early June, has now concluded. Boeing and NASA were awaiting these test results before beginning preparations for the spacecraft’s homeward journey.
An update from last week indicated, “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 test aimed to assess thruster performance issues that had caused some thrusters to be deselected during the flight, in order to understand the implications of potentially bringing those thrusters back online.
The term “de-selected” refers to thrusters that malfunctioned. There were leaks in the helium tanks that control the thrusters prior to and during the Starliner’s launch, resulting in several delays. Officials reported last month that the craft holds 70 hours of helium, significantly more than the seven hours it requires. While they indicated earlier this month that the vessel could return immediately if necessary, they noted that they are not fully prepared for that eventuality yet.
In previous communications, NASA and Boeing stated a possible return flight by the end of this month. However, the timeline has become less definite: “Boeing and NASA engineers will proceed with thruster disassembly and inspections and continue finalizing flight rationale in support of readiness reviews for Starliner’s anticipated return to Earth with commander Butch Wilmore and pilot Suni Williams in the upcoming weeks.”