that time the Soviet Union had used the R-7 to demonstrate the first full-range ICBM and
orbit the first two artificial satellites of the earth. In its intended military mission,
the R-7 was quickly overtaken by technological improvements. These allowed the Soviet
Union to build missiles using "zero warning launch" storable propellants and
smaller nuclear warheads (Yangel's R-16 and R-36, Chelomei's UR-100). Deployment of the
R-7 was very limited, and its service life extended only from 1960 to 1966. Only one
dedicated ICBM pad was built at Baykonur, and six to eight in the "Angara"
complex at Plesetsk. By 1966 they were all converted to space launch use and the military
service life of the rocket was over. But as a space launcher, the R-7, with upper
stages, became the most successful in history. By the year 2000 over 1,628 had been
launched with an unmatched success rate of 97.5% for production models. At mid-1968 the
SS-6 ICBM had been phased out of the operational inventory. Use of the SS-6 is now
restricted to space applications.