The Boeing CST-100 Starliner crew has received some encouraging news regarding their return home. The ground testing of the spacecraft’s thrusters, which has left it in orbit since early June, has recently been completed. Boeing and NASA were awaiting the results of these tests to begin preparing for the spacecraft’s journey back to Earth.
A recent update 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 reviewing the data.” The goal of these tests was to assess thruster performance degradation to better understand why some thrusters were not operational in-flight and to evaluate the potential effects of reactivating them for the Crew Flight Test.
The term “de-selected” refers to the thrusters that ceased functioning during the mission. Issues arose due to leaks in the helium tanks that power the thrusters before and during the Starliner launch, causing several delays. Officials previously indicated that the spacecraft carries an ample supply of helium—70 hours’ worth—despite only requiring seven. While they mentioned earlier this month that the craft could return immediately if necessary, they also confirmed they are not yet fully prepared for that eventuality.
NASA and Boeing have indicated that a return flight may occur at the end of this month, but the timeline has become less defined. “Boeing and NASA engineers will continue with thruster disassembly and inspections, and will proceed with finalizing flight rationale in support of readiness reviews for Starliner’s intended return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”