The Boeing CST-100 Starliner crew has received encouraging news about their eventual return to Earth. Earth-based testing of the spacecraft’s thrusters, which have left it in space since early June, has recently been completed. Boeing and NASA had been awaiting the conclusion of these tests before starting to plan the vessel’s return journey.
An update released last week confirmed, “Ground testing of a Starliner Reaction Control System (RCS) thruster at the White Sands Test Facility in New Mexico is complete, and teams are now focusing on data reviews.” The aim of the test was to assess the degradation of thrusters in order to understand why some were rendered inoperable during the flight, and to evaluate the potential consequences of reactivating those thrusters on other systems of the Crew Flight Test.
The term “de-selected” refers to thrusters that failed to operate. Prior to and during the Starliner launch, the tanks containing helium, which regulates the thrusters, experienced leaks, resulting in several delays. Officials mentioned during a press conference last month that the spacecraft has 70 hours of helium onboard, although it only requires seven. While they indicated that the craft could theoretically return to Earth at this time, they clarified that more preparation is necessary before that happens.
In their latest communication, NASA and Boeing suggested that a return flight could occur at the end of this month. However, the timeline has become less precise, stating, “Boeing and NASA engineers will proceed with thruster disassembly and inspections and work towards finalizing flight rationale in preparation for readiness reviews for Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”