Berthing a module needs corrections measured in centimeters and fractions of a degree, applied within a second or two of the vision system spotting the drift — otherwise the error has already grown by the time a correction arrives.
- Ground teleoperation — the operator's view of the module and every command they send both cross the round-trip link. By the time a correction lands, the module has moved on; the operator over-corrects for what is now stale, and the loop can overshoot into oscillation or run out of approach distance still misaligned.
- Autonomous closed-loop — an onboard vision system measures position and attitude error every frame and applies a correction immediately, with no ground round-trip in the loop at all. The controller stays stable regardless of how far away mission control is.