 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 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.
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.
| Flight No. | Date / time (UTC) | Rocket, Configuration |
Launch site | Payload | Payload mass | Orbit | Customer | Launch outcome |
|---|---|---|---|---|---|---|---|---|
| 15(F) | 12 August 1986, 20:45 |
H-I | Osaki Launch Complex | EGP (Ajisai) | LEO | Success | ||
| 9 SRMs, 2 stages | ||||||||
| 17(F) | 27 August 1987, 09:20 |
H-I | Osaki Launch Complex | ETS-5 (Kiku-5) | GTO | Success | ||
| 9 SRMs, 3 stages | ||||||||
| 18(F) | 19 February 1988, 10:05 |
H-I | Osaki Launch Complex | CS-3A (Sakura-3A) | GTO | Success | ||
| 9 SRMs, 3 stages | ||||||||
| 19(F) | 16 September 1988, 09:59 |
H-I | Osaki Launch Complex | CS-3B (Sakura-3B) | GTO | Success | ||
| 9 SRMs, 3 stages | ||||||||
| 20(F) | 5 September 1989, 19:11 |
H-I | Osaki Launch Complex | GMS-4 (Himawari-4) | GTO | Success | ||
| 6 SRMs, 3 stages | ||||||||
| 21(F) | 7 February 1990, 01:33 |
H-I | Osaki Launch Complex | MOS-1B (Momo-1B) | LEO | Success | ||
| 9 SRMs, 2 stages | ||||||||
| 22(F) | 28 August 1990, 09:05 |
H-I | Osaki Launch Complex | BS-3A (Yuri-3A) | GTO | Success | ||
| 9 SRMs, 3 stages | ||||||||
| 23(F) | 25 August 1991, 08:40 |
H-I | Osaki Launch Complex | BS-3B (Yuri-3B) | GTO | Success | ||
| 9 SRMs, 3 stages | ||||||||
| 24(F) | 11 February 1992, 01:50 |
H-I | Osaki Launch Complex | JERS-1 (FUYO-1) | LEO | Success | ||
| 9 SRMs, 2 stages | ||||||||
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).[1]
