ASTROD I, test of relativity, solar-system measurement and G-wave detection

ASTROD-I is a mission concept under study to realize the general concept of ASTROD (Astrodynamical Space Test of Relativity using Optical Devices). This mission concept has one spacecraft carrying a payload of a telescope, five lasers, and a clock together with ground stations (ODSN: Optical Deep Space Network) to test the optical scheme of interferometric and pulse ranging and yet give important scientific results. The scientific goals include a better measurement of the relativistic parameters, a better sensitivity in using optical Doppler tracking method for detecting gravitational waves, and measurement of many solar system parameters more precisely. The weight of this spacecraft is estimated to be about 300-350 kg with a payload of about 100-120 kg. The spacecraft is to be launched with initial period about 290 days and to pass by Venus twice to receive gravity-assistance for achieving shorter periods. With good orbit design, after about 370 days from launch, the spacecraft will arrive at the other side of the Sun for the determination of relativistic parameters.