Mission Orbit Design

In this paper we first describe the relations between space mission and orbit design, and then introduce the basic properties of the orbit. Geopotential representation is used to illustrate the common used Earth orbits, including Sun-synchronous orbits and Molniya orbits. Perturbation concept is used to demonstrate the mission orbits of LISA, ASTROD, and SOHO. Finally, for the interplanetary orbit design, the numerical methods of two-point boundary-value problems, the applications of fly-past, and the considerations of optimization are discussed, and are utilized to preliminarily design the mission orbit of ASTROD spacecraft to be launched in 2015.