The Boeing CST-100 Starliner crew received encouraging 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 had been awaiting these test results before finalizing plans 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 aim of the tests was to analyze thruster deterioration to understand why certain thrusters were rendered inoperable during the flight and to evaluate the potential impacts of reactivating those thrusters.
The term “de-selected” indicates that some thrusters ceased functioning. Issues arose from helium tanks controlling the thrusters, which experienced leaks prior to and during the Starliner launch, causing several delays. At a press conference last month, officials noted that the spacecraft still has 70 hours’ worth of helium available, even though only seven hours are necessary for its operation. While they stated earlier that the Starliner could return immediately if required, they indicated it is not yet fully prepared for re-entry.
Previously, NASA and Boeing mentioned that a return flight could occur at the end of this month, but the timeline has become less certain. The latest update indicates that “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.”