Kosmos 5 was the fifth satellite designated under the Kosmos system and the third spacecraft launched as part of the MS program, following Kosmos 2 and Kosmos 3. Its primary missions included developing systems for future satellites and gathering data on artificial radiation around the Earth. Kosmos 5 was the second-to-last MS satellite to be launched and the last one to successfully reach orbit. It was among several satellites inadvertently damaged or destroyed by the Starfish Prime high-altitude nuclear test on July 9, 1962, and the resulting radiation belt.