The Boeing CST-100 Starliner crew received some encouraging news regarding their return journey to Earth. Recent ground tests on the spacecraft’s thrusters, which have kept it in orbit since early June, have been successfully completed. Boeing and NASA had been awaiting the outcome of these tests to begin planning the spacecraft’s return.
An update released late last week confirmed, “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 evaluations.” The goal of the tests was to analyze any thruster degradation to understand why some thrusters were disabled during flight and assess the potential impacts of reinstating those thrusters on the overall mission.
The term “de-selected” refers to certain thrusters that malfunctioned. Prior to and during the Starliner launch, there were issues with the helium tanks that control the thrusters, resulting in multiple delays. During a press conference last month, officials noted that the spacecraft has 70 hours’ worth of helium on board, significantly more than the seven hours required for the mission. While they mentioned that the craft could return immediately if necessary, they indicated that they are not fully prepared for that eventuality.
In the most recent update, NASA and Boeing suggested that a return flight could occur by the end of this month. However, the timeline has become less specific: “Boeing and NASA engineers will proceed with the disassembly and inspection of the thrusters and continue to finalize flight rationales in preparation for readiness reviews for Starliner’s upcoming return to Earth, with commander Butch Wilmore and pilot Suni Williams.”