The H–I (H–1) was a Japanese

medium-lift launch vehicle A medium-lift launch vehicle (MLV) is a rocket launch vehicle that is capable of lifting between by NASA classification or between by Russian classification of payload into low Earth orbit (LEO).50t payloads" An MLV is between a small-lift ...

, consisting of a licence-produced American first stage and set of

booster rocket A booster is a rocket (or rocket engine) used either in the first stage of a multistage rocket, multistage launch vehicle or in parallel with longer-burning sustainer engine, sustainer rockets to augment the space vehicle's takeoff thrust and p ...

s, and all-Japanese upper stages. The H in the name represented the use of liquid hydrogen fuel in the second stage. It was launched nine times between 1986 and 1992. It replaced the N-II, and was subsequently replaced by the

H-II The H-II (H2) rocket was a Japanese satellite launch system, which flew seven times between 1994 and 1999, with five successes. It was developed by NASDA in order to give Japan a capability to launch larger satellites in the 1990s. It was the fi ...

, 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. The stage had already been produced under licence in Japan for the N-I and N-II rockets. The second stage was entirely Japanese, using an LE-5 engine, the first rocket engine in Japan to use a

cryogenic fuel Cryogenic fuels are fuels that require storage at extremely low temperatures in order to maintain them in a liquid state. These fuels are used in machinery that operates in space (e.g. rockets and satellites) where ordinary fuel cannot be used, d ...

. On launches to

Geosynchronous transfer orbit In space mission design, a geostationary transfer orbit (GTO) or geosynchronous transfer orbit is a highly elliptical type of geocentric orbit, usually with a perigee as low as low Earth orbit (LEO) and an apogee as high as geostationary orbit ...

s, a

Nissan is a Japanese multinational Automotive industry, automobile manufacturer headquartered in Yokohama, Kanagawa, Japan. The company sells its vehicles under the ''Nissan'' and ''Infiniti'' brands, and formerly the ''Datsun'' brand, with in-house ...

–built UM-69A solid motor was used as a third stage. Depending on the mass of the payload, either six or nine US Castor 2 SRMs were used as

Launch history

When the H–1 was announced in 1986, company representative Tsuguo Tatakawe clarified that it would only be used to launch indigenous (i.e. Japanese) payloads, that only two launches per year could be mounted, and that the launch window consisted of a four-month period in which Japanese fishing fleets were not active (the falling launch boosters may damage fishing nets in the ocean waters).''Japan's H–1 and H–2 rockets'',

Air & Space/Smithsonian ''Air & Space/Smithsonian'' was a quarterly magazine published by the National Air and Space Museum in Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city an ...

, February/March 1987, p. 19

References

* * * Mitsubishi Heavy Industries space launch vehicles Vehicles introduced in 1986 Thor (rocket family) Japan–United States relations {{rocket-stub

Launch history

See also

References