The laser atmosphere propagation model and three-dimensional model of lightcraft are proposed. The propulsion trajectory under single-station-circling-to-orbit mode is simulated, and the result shows that laser energy decays evidently due largely to long laser travel length in dense atmosphere. Under application target that launch Microsat using laser thruster, the three-station-relay-to-orbit modes with two different relay schemes are given and the trajectory simulation results are obtained, the ability of laser propulsion launching Microsat is studied. The results show laser that transmissio...