The N-I or N-1 was a derivative of the American Thor-Delta rocket, produced under license in Japan. The N stood for "Nippon" (Japan). It used a Long Tank Thor first stage, a Mitsubishi Heavy Industries-designed LE-3 engine on the second stage, and three Castor SRMs. Seven were launched between 1975 and 1982, before it was replaced by the N-II....
