截至1980年底,美国共进行了865次发射,其中316次属于侦察卫星。侦察卫星共分为四种类型:照相侦察卫星、导弹早期预警卫星、电子侦察卫星和海洋监视卫星。侦察卫星自空间时代开始后不久诞生以来,一直是一个重要的空间项目,并在历年各种发射中保持着巨大的比例。由于卫星寿命的不断延长,近年来它的发射次数占全年的比例已由高峰期1963年的57％降到了15％至25％的稳定状态。 As of the end of 1980, the United States conducted a total of 865 launches, of which 316 were scouting satellites. Reconnaissance satellites are divided into four types: photographic reconnaissance satellites, early warning satellites, electronic reconnaissance satellites and marine surveillance satellites. Reconnaissance satellites have been an important space project since their birth shortly after the Space Age and have maintained a large proportion of the various launches of the calendar year. Due to the prolongation of satellite life expectancy, the proportion of its launches in recent years has been reduced from 57% in peak period in 1963 to a steady state of 15% to 25%.