Even while on its Florida launching pad, the Army's satellite Explorer (official scientific name: 1958 Alpha) insistently broadcast its hoarse radio cry. Ten minutes after takeoff, Antigua in the British West Indies heard it soar triumphantly overhead. Fifteen minutes later it was radio-tracked over Ghana on the west coast of Africa. Around the earth it swept, but not until it passed homebound over California—nearly two hours after it left the ground—were the scientists sure that their bird was in a stable orbit.
The launching vehicle that put it there was a special, four-stage...