English: A comparison illustration of the Redstone ballistic missile and the Jupiter-C and Mercury-Redstone launch vehicles. The Redstone was a high-accuracy, liquid-fueled, tactical ballistic missile. The Jupiter-C was a modification of the Redstone missile originally developed as a nose-cone re-entry test vehicle for the Jupiter intermediate range ballistic missile program. A slightly altered version, the Juno I, successfully launched the first American satellite, Explorer 1, into orbit on January 31, 1958. The Mercury-Redstone was the launch vehicle for Project Mercury's sub-orbital flights; it carried the first American into space, astronaut Alan Shepard, in his Mercury spacecraft Freedom 7 on May 5, 1961.