AutoDock 1.0 : Undocking Procedures

AutoDock 1.0 Undocking procedures are defined here. Basically, undocking is really a time-reversed version of the docking with some modifications. A simplified version of the undocking procedure is covered here:

Undocking Begins

  • When the spacecraft wishes to depart from the docking station, it will send a "Undocking Request" message to the docking station.

  • The docking station will make sure that the system is not involved in any other docking or undocking procedures.

  • If no other procedures are in progress, the docking station will respond with "Undocking Allowed"

  • At this point, the spacecraft needs to get an intermediate orbit assignment. This orbit is entered temporarily before the spacecraft can proceed towards its final destination.

Orbit Assignment

  • An "Orbit Request" message is sent to the docking station, specifying details about the final destination (i.e. does the space ship intend to land on the parent planet or it in destined for deep space)

  • The docking station assigns the orbit based on the final destination. If the spacecraft is headed for the parent planet, an inner orbit is assigned. If the spacecraft is destined for deep space, an outer orbit is assigned.

  • The docking station replies with an "Orbit Assign" message, giving details about the assigned orbit.

  • Once an orbit has been obtained the airlock is sealed on the spacecraft side.

  • The spacecraft also computes the plan to attain the assigned orbit.


  • Spacecraft then sends "Ready For Undocking" message indicating that it is ready to leave.

  • The docking station seals the airlock and replies with "Proceed For Undocking" with the recommended velocity for undocking.

  • At this point, the spacecraft sends "Undocking Now" and leaves for the assigned orbit.

  • Once the spacecraft reaches the assigned orbit, it sends "Orbit Achieved" message to the docking station.

  • At this point, the docking station frees up the docking port and replies with "Undocking Completed".

  • At this point, the docking station will schedule other pending docking/undocking requests.

  • When the spacecraft leaves the assigned orbit, frees up the orbit by sending "Orbit Deassign"

  • The docking station frees up the orbit and sends "Orbit Deassign Ack" to the spacecraft.