The Boeing CST-100 Starliner crew has received some 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 completed. Boeing and NASA had been waiting for these tests before outlining plans for the vessel’s homeward journey.
An update released last week stated, “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 the reasons behind the in-flight failure of some thrusters and to assess any potential impacts of reusing those thrusters for the upcoming Crew Flight Test.
Some thrusters were “de-selected,” meaning they ceased to function. There were issues with helium tanks controlling the thrusters, which experienced leaks prior to and during the Starliner’s launch, causing several delays. Officials noted at a press conference last month that the spacecraft contains 70 hours’ worth of helium, despite only requiring seven hours. While they previously mentioned that the craft could return if necessary, they indicated they are not quite prepared for that eventuality.
In the latest update, NASA and Boeing suggested that a return flight could occur toward the end of this month. However, the timeline has become less specific: “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.”