The crew of the Boeing CST-100 Starliner has received encouraging news regarding its return to Earth. Recent ground tests of the spacecraft’s thrusters, which have kept it in space since early June, have been completed. Boeing and NASA had been awaiting these tests to initiate plans for the spacecraft’s homecoming.
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 turning their attention to data reviews.” The purpose of the tests was to assess thruster degradation, helping teams understand why some thrusters were inoperative during flight and the potential impacts of reinstating those thrusters on the Crew Flight Test.
The term “de-selected” refers to thrusters that ceased functioning. Issues arose with the helium tanks controlling the thrusters, which had leaks both prior to and during the Starliner launch, resulting in multiple delays. At a press conference last month, officials noted that the spacecraft has 70 hours’ worth of helium, far exceeding the 7 hours required. While NASA had stated earlier this month that the craft could return immediately if necessary, they also indicated they were not fully prepared for that scenario.
In their latest update, NASA and Boeing suggested a return flight might occur at the end of this month, but the timeline has now become less specific: “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.”