The most important mission of the American and Soviet militaries in times of peace was prevention of accidental or unauthorized launch of nuclear weapons. The command, control, and communication network was also believed to be vital to the national interest because it helped assure nuclear retaliation. For obvious reasons, each side had to know what the other was up to. In part, the needed information has been gathered through traditional activities such as spying and analysis of open publications. In part, it has been gathered through sophisticated technologies such as radar and satellites.
Early detection is considered particularly important in deterring nuclear war.
Satellites Like some nuclear warheads, satellites are carried into space by rockets. But, instead of being propelled back to earth, they are propelled into orbit around it. In the early 1980s, some three-quarters of all space missions had military purposes, 8a and every third day saw the launch of a new military satellite. 8c Satellites are gradually being equipped with means of destroying fellow satellites and of defending themselves from attack. If military competitions among major world powers overtake humanity again, these developments could turn out to be critically important to warfare and to the fate of the earth.