The crew of the Boeing CST-100 Starliner has received encouraging news regarding its return to Earth. Recent ground tests of the spacecraft’s thrusters, which have left it in orbit since early June, have been successfully completed. Boeing and NASA were waiting for these tests to finish before planning the return journey.
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 data reviews.” The tests aimed to assess thruster performance and understand the reasons behind the in-flight failures of some thrusters, as well as the implications of possibly reactivating them.
The term “de-selected” indicates that some thrusters ceased functioning. Issues with the helium tanks controlling the thrusters, which experienced leaks prior to and during the Starliner’s launch, contributed to delays. Officials noted last month that the spacecraft carries 70 hours of helium despite only requiring seven hours. Although they indicated earlier this month that the Starliner could return to Earth immediately if necessary, they also mentioned that they are not yet fully prepared for the return.
The latest communication from NASA and Boeing suggested that a return flight might occur by the end of this month. However, the timeline is now less specific, with the statement: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and move forward with finalizing flight rationale in support of readiness reviews for Starliner’s planned return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”