PURPOSE: To improve mounting efficiency in a satellite and to improve storing capacity of a rocket when required electricity is increased and at lifting off.

CONSTITUTION: An artificial satellite has a satellite body structure 2 as an artificial satellite body and a gravity mass part satellite body structure 3 as a gravity mass part to keep gravity balance on the orbit of this satellite body structure 2. And equipment of a predetermined weight is loaded onto the gravity mass part satellite body structure 3, a solar battery panel 3C is attached to an outer surface 3B of the gravity mass part satellite body structure 3, and the satellite body structure 2 is coupled with the gravity mass part satellite body structure 3 through a telescopic mast 4 as a telescopic mast.