The Long March 1 is basically a DF-4 with a solid third stage and a fairing. So the FG-02 was developed as the third stage to add to the stack. It was initially tested on two launches aboard T-7A sounding rockets to validate high altitude ignitions. Both successful flights were performed in August 1968. Before going into the launch vehicle, the propellant load was increased from 900 kg (2,000 lb) to 1,806 kg (3,982 lb). It performed just two orbital flights, both from Jiuquan and both successful. The first was on April 24, 1970, to orbit the indigenous satellite, the Dong Fang Hong I. And the second was on March 3, 1971, on the Shijian 1 mission.[3]