The Boeing CST-100 Starliner team has received positive news regarding the spacecraft’s return to Earth. Recently, ground tests on the spacecraft’s thrusters, which have prevented its descent since early June, have been completed. Boeing and NASA were waiting for these tests before initiating plans for the spacecraft’s homecoming.
An update from last week announced, “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 purpose of the test was to observe any degradation of the thrusters, which would help teams understand why some were inoperable during the flight and assess the implications of possibly reactivating those thrusters for the Crew Flight Test’s remainder.
The term “de-selected” refers to the thrusters that ceased functioning. Issues arose with the helium tanks that control the thrusters, which were found to be leaking both before and during the Starliner launch, resulting in several delays. Officials indicated at a press conference last month that the spacecraft has 70 hours’ worth of helium, despite only needing seven for its operations. While they mentioned that the spacecraft could technically return to Earth now, they emphasized that they are not yet fully prepared for that outcome.
In their latest communication, NASA and Boeing have suggested that a return flight could occur by the end of this month, though the timeframe has now become less certain. “Boeing and NASA engineers will proceed with thruster disassembly and inspections and will continue to finalize flight rationale in preparation for readiness reviews for Starliner’s standard return to Earth with Commander Butch Wilmore and Pilot Suni Williams in the coming weeks.”