The Boeing CST-100 Starliner crew has received encouraging news regarding their eventual return to Earth. Ground tests of the spacecraft’s thrusters, which have prevented it from returning since early June, have recently concluded. Boeing and NASA had been waiting for these tests to finalize plans for the spacecraft’s homecoming.
An update from 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 purpose of the test was to analyze thruster degradation to understand why some thrusters were deactivated during flight and the potential impacts of reactivating them.
The term “de-selected” indicates that certain thrusters ceased functioning. Prior to and during the Starliner’s launch, the helium tanks that manage the thrusters experienced leaks, leading to several delays. Officials mentioned last month that the spacecraft has 70 hours’ worth of helium onboard, despite only needing seven for its operations. While they indicated earlier this month that the craft could return immediately if necessary, they clarified that they are not yet prepared for that eventuality.
In their latest update, NASA and Boeing suggested that a return flight might occur at the end of this month. However, the timeline has become less certain: “Boeing and NASA engineers will continue with thruster disassembly and inspections, and will proceed with finalizing flight rationale for readiness reviews in anticipation of Starliner’s standard return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”