Oribt Design and Poingting Ahead Angle for Astrod 1

As the first step of ASTROD (Astrodynamical Space Test of Relativity using Optical Devices), ASTROD 1 is one spacecraft launched to a solar orbit to test the experimental schemes for ASTROD and to meet important scientific goals.Because a laser beam is transmitted to the spacecraft which will be near the other side of the sun and the laser takes about 1000 s from a ground station to the S/C, the Telescope Pointing Ahead needs to be considered.The orbit simulation, the way to judge the orbit precision, the relation between the Telescope Pointing Ahead and the position of the earth and the spacecraft are presented in this paper.