H-I
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. 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, which used the same upper stages with a Japanese first stage.
H-I rocket | |
| Function | Carrier rocket |
|---|---|
| Manufacturer | McDonnell Douglas (design) Mitsubishi Heavy Industries (production) |
| Country of origin | Japan (production) United States (design) |
| Size | |
| Height | 42 metres (138 ft) |
| Diameter | 2.44 metres (8.0 ft) |
| Mass | 142,260 kilograms (313,630 lb) |
| Stages | 2 or 3 |
| Capacity | |
| Payload to LEO | |
| Mass | 3,200 kilograms (7,100 lb) |
| Payload to GTO | |
| Mass | 1,100 kilograms (2,400 lb) |
| Associated rockets | |
| Family | Thor |
| Comparable | Delta 3000, PSLV |
| Launch history | |
| Status | Retired |
| Launch sites | LA-N, Tanegashima |
| Total launches | 9 |
| Success(es) | 9 |
| First flight | 12 August 1986 |
| Last flight | 11 February 1992 |
| Boosters – Castor 2 | |
| No. boosters | 6 or 9 |
| Powered by | 1 TX-354-3 |
| Maximum thrust | 258.9 kilonewtons (58,200 lbf) |
| Specific impulse | 262 sec |
| Burn time | 37 seconds |
| Propellant | Solid |
| First stage – Thor-ELT | |
| Powered by | 1 MB-3-3 |
| Maximum thrust | 866.7 kilonewtons (194,800 lbf) |
| Specific impulse | 290 sec |
| Burn time | 270 seconds |
| Propellant | RP-1/LOX |
| Second stage | |
| Powered by | 1 LE-5 |
| Maximum thrust | 102.9 kilonewtons (23,100 lbf) |
| Specific impulse | 450 sec |
| Burn time | 370 seconds |
| Propellant | LH2/LOX |
| Third stage (optional) | |
| Powered by | 1 UM-129A |
| Maximum thrust | 77.4 kilonewtons (17,400 lbf) |
| Specific impulse | 291 sec |
| Burn time | 68 seconds |
| Propellant | Solid |
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. On launches to Geosynchronous transfer orbits, a Nissan–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 booster rockets.