The Boeing CST-100 Starliner crew has received encouraging news regarding their return to Earth. Recent ground tests on the spacecraft’s thrusters, which have left the vehicle stranded in orbit since early June, have been successfully completed. Both Boeing and NASA had been awaiting the results of these tests to initiate plans for the capsule’s re-entry.
An update released late 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 these tests was to assess thruster degradation to better understand issues that caused certain thrusters to become inactive during the flight, and to evaluate the potential impact of reactivating them on the Crew Flight Test.
The term “de-selected” refers to thrusters that malfunctioned. Prior to and during the Starliner’s launch, helium tanks that control the thrusters experienced leaks, causing several delays. At a press conference last month, officials mentioned that the spacecraft is equipped with 70 hours’ worth of helium when only seven are necessary. While they indicated that the ship could technically return immediately if required, they also emphasized that they are not fully prepared for that scenario.
In their most recent update, NASA and Boeing mentioned a potential return flight by the end of this month. However, this timeframe has since 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.”