The Boeing CST-100 Starliner crew has received some encouraging news regarding their return to Earth. Recently, ground testing of the spacecraft’s thrusters, which have left it in orbit since early June, has been completed. Boeing and NASA were awaiting the results of these tests to initiate the planning for the spacecraft’s return journey.
An update provided 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 focusing on data reviews.” The purpose of the test was to analyze thruster performance and understand the reasons behind the deactivation of some thrusters during flight, as well as the potential effects of reactivating them on the rest of the Crew Flight Test.
The term “de-selected” refers to the thrusters that failed to function. Prior to and during the Starliner’s launch, the helium tanks controlling the thrusters suffered leaks, which caused multiple delays. During a press conference last month, officials mentioned that the spacecraft has 70 hours’ worth of helium on board, while only 7 hours are required for its operations. Although they indicated earlier this month that the spacecraft could return immediately if necessary, they also stated they are not fully prepared for that scenario.
In the latest update, NASA and Boeing suggested that a return flight could happen at the end of the month, but the timeline has now 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.”