The crew of the Boeing CST-100 Starliner has received positive news regarding their return to Earth. Recent ground tests of the spacecraft’s thrusters, which have left it in orbit since early June, have been successfully completed. Boeing and NASA were waiting for these tests to be finalized before they could start planning for the spacecraft’s homeward journey.
An update released 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 purpose of the tests was to assess the performance of the thrusters and understand why some were deactivated during the flight, as well as the potential effects of bringing those thrusters back online for the Crew Flight Test.
The term “de-selected” refers to the thrusters that ceased functioning. Prior to and during the Starliner launch, the helium tanks that control the thrusters experienced leaks, causing several delays. Officials noted last month that the spacecraft has 70 hours of helium on board, although only seven hours are needed for its operations. While they mentioned earlier this month that the Starliner could return immediately if necessary, there are still preparations to be completed before that can happen.
In their most recent update, NASA and Boeing indicated that a return flight might occur by the end of this month. However, the timelines have now become less definitive: “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.”