The Boeing CST-100 Starliner crew has received encouraging news about the spacecraft’s return to Earth. The ground testing of the spacecraft’s thrusters, which have kept it stranded in orbit since early June, has concluded. Boeing and NASA were awaiting the results of these tests to begin organizing the vessel’s return.
An update released 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 reviewing the data.” The purpose of the tests was to investigate thruster degradation to better understand why certain thrusters malfunctioned during flight and to assess the implications of potentially reinstating those thrusters for the Crew Flight Test.
Some thrusters were labeled “de-selected,” meaning they had failed to operate. Prior to and during Starliner’s launch, the helium tanks that regulate the thrusters experienced leaks, resulting in several delays. Last month, officials indicated that while the spacecraft has 70 hours’ worth of helium onboard—far more than the seven hours required—it is not yet prepared for a return.
In their most recent update, NASA and Boeing mentioned that a return flight could occur at the end of this month. However, the timeline has become less certain: “Boeing and NASA engineers will continue with thruster disassembly and inspections, and will work on finalizing flight rationale to support readiness reviews for Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”