Autonomy stops before attachment. Although Cygnus flies itself to the International Space Station, its arrival ends with a robotic handoff rather than the spacecraft driving its own connection into place. That distinction is deliberate. Built to deliver cargo, Cygnus uses a berthing interface, which requires the station's robotic arm to capture and position it for attachment.
Berthing is not failed docking. During rendezvous and proximity operations, onboard guidance, navigation and control systems steer Cygnus toward a designated capture position, where it holds relative to the station while operators oversee the approach. Then Canadarm2 takes over. The arm grasps a grapple fixture on the spacecraft, after which the captured vehicle can be moved toward a station port without performing a docking maneuver under its own propulsion. The hardware decides the method. Cygnus carries the passive side of the Common Berthing Mechanism, whose mating interface is joined to the station's active side and secured with powered bolts.
The distinction has practical consequences. A docking spacecraft uses compatible docking hardware to make the initial connection through its own controlled approach, whereas a berthed vehicle depends on external handling to bring the mating surfaces together. Neither method defines intelligence. For Cygnus, the division of labor pairs autonomous flight with station robotics, while its broad berthing passage accommodates the transfer of cargo once attachment and checks are complete. Arrival remains a shared operation. After crossing the distance under computer control, the spacecraft waits beside its destination, leaving the final movement to a machine already anchored there. The traveler becomes the load.
