The crew of the Boeing CST-100 Starliner received encouraging news about their upcoming return to Earth. Recent ground testing of the spacecraft’s thrusters, which has kept it in orbit since early June, has been completed. Boeing and NASA were waiting for these tests to finish before starting plans for the spacecraft’s homecoming.
An update from last week indicated, “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 turning their attention to data reviews.” The purpose of the tests was to analyze thruster performance and understand why some thrusters were not functioning properly during flight.
The term “de-selected” refers to the thrusters that stopped working. Issues with the helium tanks that control the thrusters caused delays both before and during the Starliner’s launch. Officials revealed last month that the spacecraft has 70 hours of helium on board when only seven hours are needed for a safe return. While they noted that the craft could technically come back to Earth if necessary, they are not fully prepared for the landing just yet.
In their most recent update, NASA and Boeing indicated that a return flight might occur at the end of this month. However, the timeline has become less certain: “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.”