Earth observation satellite often encounters unexpected situations such as finding a new target

failing to perform the original observation tasks. To improve the operation efficiency of observation satellite

and make a rapid response to the unexpected observation tasks in the absence of ground supports

researchers need to design ground-onboard joint operation mechanism for the autonomous mission planning. Firstly

aiming at the autonomous operation of imaging satellite cluster

this paper divides the problem into two parts: the ground task planning and onboard autonomous planning. Furthermore

based on full consideration of the resources of ground station and satellite

and the requirments of observation task planning

a ground-onboard joint operation mechanism of mission planning is proposed

together with the detailed operation process. The result of the distributed simulation software shows that the mechanism can carry out an effective coordination between the on-board autonomous mission planning and the ground planning. It can reflect the controller's intention

taking advantage of ground computing ability and onboard real-time flexibility to rapid response on unexpected tasks. It can solve the problem of response delay on ground to the unexpected observation tasks

limited computing resources onboard and the cooperation between onboard planning and ground planning. The research achievements can effectively improve the response ability of the remote sensing satellite to the unexpected observation mission.