The H-I or H-1 was a Japanese liquid-fuelled carrier rocket, consisting of a licence-produced American first stage and set of booster rockets, and all-Japanese upper stages. It was launched nine times between 1986 and 1992. It replaced the N-II, and was subsequently replaced by the H-II, which used the same upper stages with a Japanese first stage.The first stage of the H-I was a licence-built version of the Thor-ELT, which was originally constructed for the US Delta 1000 rocket.