On 9 July 1962, decay of debris the Starfish Prime nuclear test utccreated an unexpected increase in high-energy particles in the Earth's magnetic field.

The Air Force Cambridge Research Laboratory was asked to design and build STARAD to study the radiation.

[2] The STARAD vehicle was designed and built in sixty days and was launched from Vandenberg Air Force Base on 26 October 1962.

[4] The satellite's existence was kept secret for some time, as were the conclusions that the artificial radiation belt could last ten years or longer.

The unfavorable conclusions worsened existing criticism of the Starfish test among the scientific community.