The Boeing CST-100 Starliner crew has received encouraging news regarding their return to Earth. The recent conclusion of ground testing on the spacecraft’s thrusters, which have left it in orbit since early June, paves the way for planning its homeward journey. Boeing and NASA had been awaiting these tests before deciding on the Starliner’s next steps.
An update released last week indicated, “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 test was to assess thruster degradation to better understand why certain thrusters were deactivated during flight and what effects reactivating them might have on the remaining systems of the Crew Flight Test.
The term “de-selected” refers to thrusters that became non-operational. Prior to and during the Starliner’s launch, the helium tanks controlling the thrusters suffered from leaks, resulting in several delays. Officials disclosed at a recent press conference that the spacecraft currently contains 70 hours’ worth of helium, despite needing only seven for its operations. While they previously stated that the Starliner could return immediately if necessary, they also indicated that they are not fully prepared for that eventuality.
In their last communication, NASA and Boeing mentioned that a return flight could occur at the end of this month. However, updates now suggest a less defined timeframe: “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.”