What did the necessity of returning the Starliner empty suggest about its readiness for nominal crewed departure?
The system was not yet fully cleared for nominal crewed departure and landing.
The action of deliberately returning the Starliner without its crew strongly implies that, despite the successful docking and management of some in-flight issues, the vehicle had not yet received full clearance for a standard, nominal crewed departure and subsequent landing. The decision stemmed from a preference for absolute safety based on engineering concerns regarding the thruster performance under operational stress. Engineers chose the conservative posture of spending weeks analyzing the problematic data while the astronauts waited at the ISS, rather than risking a hasty sign-off for reentry, thereby confirming the system was not yet fully approved for the final step of the certification process.
