Explorer 1 (January 31, 1958)

Explorer 1 was the first satellite launched by the United States when it was sent into space on January 31, 1958. The primary science instrument on Explorer 1 was a cosmic ray detector designed to measure the radiation environment in Earth orbit. the U.S. Army Ballistic Missile Agency was directed to launch a satellite using its Jupiter C rocket developed under the direction of Dr. Wernher von Braun.Once in space this experiment, provided by Dr. James Van Allen of the University of Iowa, revealed a much lower cosmic ray count than expected.

 Raw image extracted from vintage video.