The crew of the Boeing CST-100 Starliner has received promising news regarding their impending return to Earth. Recent ground testing of the spacecraft’s thrusters, which have left it in orbit since early June, has been successfully completed. Boeing and NASA had been awaiting these tests to begin preparations for the Starliner’s voyage home.
An update from 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 analysis.” The purpose of these tests was to investigate thruster degradation to understand the reasons behind the in-flight de-selection of some thrusters and to assess the implications of possibly restoring those thrusters for the remainder of the Crew Flight Test.
The term “de-selected” refers to thrusters that ceased functioning. Prior to and during the launch of the Starliner, the helium tanks that control the thrusters experienced leaks, causing several delays. Officials stated last month that while there is currently 70 hours’ worth of helium onboard, only seven hours are necessary for operation. Although they indicated earlier this month that the spacecraft could return immediately if needed, they clarified that the time is not yet right for landing.
In their latest communication, NASA and Boeing noted that a return flight was expected at the end of this month. However, the timeframe has become less specific: “Boeing and NASA engineers will now proceed with thruster disassembly and inspections, and will continue to finalize the flight rationale in support of readiness reviews for Starliner’s scheduled return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”