The Boeing CST-100 Starliner crew received some encouraging news about the spacecraft’s return home. Ground tests for the spacecraft’s thrusters, which have kept it in orbit since early June, were recently completed. Boeing and NASA had awaited these tests before outlining plans for the vessel’s return trip.
An update released last week noted, “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 data reviews.” The objective of these tests was to examine the degradation of the thrusters to better understand why some malfunctioned during flight and to evaluate the implications of reintroducing those thrusters for the remainder of the Crew Flight Test.
The term “de-selected” referred to thrusters that ceased functioning. There were issues with helium tanks that control the thrusters, which experienced leaks leading up to and during the Starliner’s launch, causing several delays. At a press conference last month, officials stated that the spacecraft has an excess of helium onboard—70 hours’ worth—despite only needing seven hours. They mentioned that while the craft could technically return home now, they are not yet prepared for that eventuality.
Recent updates from NASA and Boeing suggested that a return flight might be possible by the end of the month. However, the timeline has become less defined: “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.”