Juno I

The Juno I was a four-stage American booster rocket that launched America's first satellite, Explorer 1, in 1958. The Juno I consisted of a Jupiter-C first stage, based on the Redstone missile; with three additional solid fuel stages based on the Sergeant missile to provide the added impulse to achieve orbit. Juno I is commonly confused with the Juno II launch vehicle, which was derived from the PGM-19 Jupiter medium-range ballistic missile.