H-II
The launch of H-II Flight 4, carrying ADEOS I
|
|
| Function | Launch vehicle |
|---|---|
| Manufacturer | Mitsubishi Heavy Industries |
| Country of origin | Japan |
| Size | |
| Height | 49 m (161 ft) |
| Diameter | 4 m (13 ft) |
| Mass | 260,000 kg (570,000 lb) |
| Stages | 2 |
| Capacity | |
| Payload to LEO | 10,060 kg (22,180 lb) |
| Payload to GTO |
3,930 kg (8,660 lb) |
| Associated rockets | |
| Family | H-II |
| Derivatives | H-IIA, H-IIB |
| Comparable | Ariane 4 |
| Launch history | |
| Status | Retired |
| Launch sites | LC-Y, Tanegashima |
| Total launches | 7 |
| Successes | 5 |
| Failures | 1 |
| Partial failures | 1 |
| First flight | 3 February 1994 |
| Last flight | 15 November 1999 |
| Boosters | |
| No. boosters | 2 |
| Engines | 1 Solid |
| Thrust | 1540 kN |
| Specific impulse | 273 s (2.68 km/s) |
| Burn time | 94 seconds |
| Fuel | Solid |
| First stage | |
| Engines | 1 LE-7 |
| Thrust | 1,078 kN (242,000 lbf) |
| Specific impulse | 446 s (4.37 km/s) |
| Burn time | 346 seconds |
| Fuel | LOX / LH2 |
| Second stage | |
| Engines | 1 LE-5A |
| Thrust | 121.5 kN (27,300 lbf) |
| Specific impulse | 452 seconds |
| Burn time | 600 seconds |
| Fuel | LOX / LH2 |
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 first two-stage liquid-fuelled rocket Japan made using only technologies developed domestically. It was superseded by the H-IIA rocket following reliability and cost issues.
Prior to H-II, NASDA had to use components licensed by the United States in its rockets. In particular, crucial technologies of H-I and its predecessors were from the Delta rockets. Although the H-I did have some domestically produced components, such as LE-5 engine on the second stage and inertial guidance system, the most crucial part, the first stage engine, was a licence-built version of the Thor-ELT of the US. By developing the LE-7 liquid-fuel engine and the solid booster rockets for the first stage, all stages of H-II had become "domestically developed".
The H-II was developed under the following policies, according to a NASDA press release:
Development of the LE-7 engine which started in 1984 was not without hardships, and a worker died in an accidental explosion. The first engine was completed in 1994, two years behind the original schedule. In 1990, Rocket System Corporation was established to operate the launch missions after the rockets' completion.
In 1994, NASDA succeeded in launching the first H-II rocket, and succeeded in five launches by 1997. However, each launch cost 19 billion yen (190 million USD), too expensive compared to international competitors like Ariane. (This is in part due to the changes in exchange rates, which was 240 yen to a dollar when the project planning started in 1982, but had changed to 100 yen a dollar by 1994.) Development of the next-generation H-IIA rockets started in order to minimize launch costs.
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