The Boeing CST-100 Starliner is showing signs of progress toward its eventual return to Earth. Recent successful ground tests of the spacecraft’s thrusters, which have left it in space since early June, have been completed. Boeing and NASA were awaiting these tests to start organizing the craft’s return journey.
“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 reviewing the data,” a recent update states. The goal of the tests was to examine thruster degradation, which could provide insights into why some thrusters were deactivated during flight and the potential effects of reactivating them on the remainder of the Crew Flight Test.
The term “de-selected” refers to the thrusters that ceased functioning. Prior to and during the Starliner’s launch, the helium tanks that control these thrusters experienced leaks, causing several delays. Last month, officials noted that the spacecraft has 70 hours of helium on board, although only seven hours are required for operation. They mentioned that while the craft could technically return now if necessary, further preparations are still in progress.
In the latest update, NASA and Boeing indicated the possibility of a return flight by the end of this month. However, this timeframe has become less specific: “Boeing and NASA engineers will continue with thruster disassembly and inspections, and advance with finalizing the flight rationale in support of readiness reviews for Starliner’s scheduled return to Earth with commander Butch Wilmore and pilot Suni Williams in the weeks ahead.”