The first successful launch of a Chinese 1059 SRBM missile copy of the R-2 was conducted only two months later on November 5, 1960. The missile was also designated DF-1. The first DF-2 MRBM was tested on March 21, 1962, but failed. Development eventually continued with the redesigned DF-2A MRBM which was successfully tested on June 29, 1964. It would enter service by the end of 1966. The first successful launch and recovery of a T-7A(S1) sounding rocket carrying a biological experiment (transporting eight white mice) was on July 19, 1964 from Base 603 (安徽广德誓节渡中国科学院六〇三基地. China started to develop the DF-5 intercontinental ballistic missile (ICBM) program in August 1965. It was designed to carry a single nuclear warhead and has a maximum range of 12000 km. In November 1966, it was decided to build a second ballistic missile test site, the Northern Missile Test Site (华北导弹试验场)) in Shanxi Province, farther away from China's northern border. On October 27, 1966, a nuclear-tipped DF-2A missile was launched from Jiuquan and the 20 kilotons yield nuclear warhead exploded at the height of 569 meters over the target in Lop Nor or Base 21 situated 894 km away. On December 26, 1966, China tested its first indigenously developed DF-3 intermediate-range ballistic missile (IRBM) with success. The DF-3 was a single-stage, single-warhead missile with a maximum range of 2500 km. The development of the DF-4 IRBM began in 1967 in parallel with the single-stage DF-3. In March 1967, development started on the JL-1 submarine-launched ballistic missile to accompany the Type 092 ballistic missile submarine (SSBN) also in development.