Fifty four years ago today, on the 1st of February 1958, the United States finally had a successful launch of a earth-orbiting satellite. Explorer I followed the successful soviet launches of Sutnik1 and Sputnik 2. Unlike those two satellites Explorer I would continuously orbit the earth until March 19th 1970.
Almost half of the Explorer I satellite’s weight (13.79Kg) was mercury batteries, which gave out on May 23rd 1958. Until that time the satellite transmitted real scientific data. The Geiger counter alone was responsible for the discovery of the Van Allen Radiation Belt.
The satellite was long and thin, and was designed to rotate like a bullet around it’s long axis. Shortly after entering orbit the rotational axis began to precess. This left the satellite wildly flopping through its orbit. In the end Explorer I flopped around the earth over 58,000 times.