H series (Japanese rockets) A family of Japanese launch vehicles used by NASDA (National Space Development Agency) which consists, in chronological order of development, of the H-1, H-2, and H-2A and their variants. The H-1 was a license-built version of the US Delta rocket, whereas the H-2 and H-2A are entirely Japanese in design and construction. H-1 The first stage of the H-1 was essentially the same as that of the N-2 (see N series) with a liquid oxygen (LOX)/kerosene main engine and 6-9 small solid-propellant strap-on boosters. The second stage was of Japanese origin, built by Mitsubishi Heavy Industries, and burned LOX/liquid hydrogen. A small solid-propellant third stage designed by Nissan enabled payloads of up to 1,100 kg to be placed in geostationary transfer orbit (GTO). The H-1 program was operational between 1986 concluded in 1992 with nine successes and no failures. H-2 To provide greater payload capacity and to permit unencumbered commercial space transportation offerings (the Delta licensing agreement restricted the use of the H-1 for commercial flights), Japan developed the H-2 launch vehicle based on all-Japanese propulsion systems. The H-2, which made 7 successful flights between 1994 and 1999, could lift payloads four times heavier than those of the H-1 – up to 10 tons into low Earth orbit (LEO) or up to 4 tons in GTO – and opened the door to NASDA spacecraft designed to explore the Moon and planets. The first mission, on Feb. 3, 1994, deployed one payload into LEO and then carried an experimental package VEP (Vehicle Evaluation Payload) to GTO. Dwarfing its predecessor, the H-2 consisted of a two-stage core vehicle, burning LOX and liquid hydrogen in both stages, with two large solid-propellant strap-on boosters. Nissan produced the 4-segmented strap-on boosters which are considerably larger than the main stages of ISAS’s (Institute of Space and Astronautical Science’s) M-3 and M-5 vehicles (see M series). The LE-7 first-stage main engine overcame numerous developmental difficulties, while the LE-5A engine used by the second stage is an upgraded version of the proven LE-5 flown on the second stage of the H-1. H-2A
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