The Boeing CST-100 Starliner crew has received encouraging news regarding their return journey. Earthbound testing of the spacecraft’s thrusters, which have kept it in orbit since early June, has recently been completed. Boeing and NASA had been waiting for these tests to conclude before initiating plans for the spacecraft’s homecoming.
An update shared last week noted, “Ground testing of a Starliner Reaction Control System (RCS) thruster at White Sands Test Facility in New Mexico is complete, and teams are now focused on reviewing the data.” The objective of the tests was to assess the degradation of thrusters, in order to understand the reasons behind some thrusters being deemed inoperable during flight and to gauge any potential impacts of reinstating those thrusters for the Crew Flight Test.
The term “de-selected” refers to thrusters that failed to operate effectively. There were issues with helium tanks that control the thrusters, leading to several delays prior to and during the Starliner’s launch. Officials reported last month that the spacecraft has 70 hours of helium aboard, despite only needing seven for its operations. While they indicated earlier in the month that the spacecraft could return immediately if necessary, they also mentioned that they were not fully prepared for such an event.
In their most recent update, NASA and Boeing suggested that a return flight might occur by the end of this month. However, this timeline has since become less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and will continue to finalize flight rationale in support of readiness reviews for Starliner’s upcoming return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”