H-II rocket at Tsukuba science museum & planetarium
FunctionLaunch vehicle
ManufacturerMitsubishi Heavy Industries
Nissan Motors (sub)
Alliant Techsystems (sub, for the SSBs)
Country of originJapan
Height49 m (161 ft)
Diameter4 m (13 ft)
Mass260,000 kg (570,000 lb)
Payload to LEO
Mass10,060 kg (22,180 lb)
Payload to GTO
Mass3,930 kg (8,660 lb)
Associated rockets
Derivative workH-IIA, H-IIB
ComparableAriane 4
Launch history
Launch sitesLC-Y, Tanegashima
Total launches7
Partial failure(s)1
First flight3 February 1994
Last flight15 November 1999
No. boosters2
Powered by1 Solid
Maximum thrust1,540 kN (350,000 lbf)
Specific impulse273 s (2.68 km/s)
Burn time94 seconds
First stage
Powered by1 LE-7
Maximum thrust1,078 kN (242,000 lbf)
Specific impulse446 s (4.37 km/s)
Burn time346 seconds
PropellantLH2 / LOX
Second stage
Powered by1 LE-5A
Maximum thrust121.5 kN (27,300 lbf)
Specific impulse452 s (4.43 km/s)
Burn time600 seconds
PropellantLH2 / LOX

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.[1] It was the first two-stage liquid-fuelled rocket Japan made using only technologies developed domestically.[2] It was superseded by the H-IIA rocket following reliability and cost issues.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 (the manufacturer of the Delta rockets, McDonnell Douglas, later Boeing and the United Launch Alliance, would later use the H-IIA's technologies (the rocket itself is the successor to the H-II) to create the Delta III, albeit short lived). 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:[1]

  1. Develop the launch vehicle with Japanese space technology.
  2. Reduce both development period and costs by utilizing developed technologies as much as possible.
  3. Develop a vehicle which can be launched from the existing Tanegashima Space Center.
  4. Use design criteria which allows sufficient performance for both the main systems and subsystems. Ensure that development will be carried out properly, and safety is taken into account.

The H-II was new, incorporating larger LH2/LOX tanks, and a new upper stage, consisting of a cylindrical LH2 tank with a capsule-shaped LOX tank. The LH2 tank cylinder carried payload launch loads, while the LOX tank and engine were suspended below within the rocket's inter-stage. The second stage was powered by a single LE-5A engine.[3]


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. The Rocket Systems Corporation (RSC), a consortium of 74 companies including Mitsubishi Heavy Industries, Nissan Motors, and NEC, was established in 1990 to manage launch operations after the rockets' completion. In 1992, it had 33 employees.[4]

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 (US$190 million), too expensive compared to international competitors like Ariane. (This is in part due to the Plaza Accord's changes to the exchange rate, 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.

In 1996, RSC signed a contract with the Hughes Space and Communications Group to launch 10 satellites. The successive failure of flight 5 in 1998 and flight 8 in the following year brought an end to the H-II series and the contract with Hughes.[5] To investigate the cause of the failure and to direct resources into the H-IIA, NASDA cancelled flight 7 (which was to be launched after F8 due to changes in schedule), and terminated the H-II series.[2]

Launch history

Main article: List of H-II and H3 launches

Flight No. Date / time (UTC) Rocket,
Launch site Payload Payload mass Orbit Customer Launch
TF1 (Test Flight) 3 February 1994
H-II Yoshinobu Launch Complex OREX (Orbital Re-entry Experiment), VEP (Vehicle Evaluation Payload) LEO / GTO Success
Ryūsei, Myōjō
TF2 28 August 1994
H-II Yoshinobu Launch Complex ETS-VI (Engineering Test Satellite-VI) GEO Success
Kiku 6
TF3 18 March 1995
H-II Yoshinobu Launch Complex GMS-5 (Geostationary Meteorological Satellite-5) / SFU (Space Flyer Unit) GEO / LEO Success
Himawari 5
F4 17 August 1996
H-II Yoshinobu Launch Complex ADEOS I (Advanced Earth Observing Satellite) / Fuji OSCAR 29, JAS-2 LEO Success
Midori, Fuji 3
F6 November 27, 1997
H-II Yoshinobu Launch Complex TRMM (Tropical Rainfall Measuring Mission) / ETS-VII (Engineering Test Satellite-VII) LEO Success
Kiku 7 (Orihime & Hikoboshi)
F5 February 21, 1998
H-II Yoshinobu Launch Complex COMETS (Communications and Broadcasting Engineering Test Satellites) GEO Partial failure
Kakehashi, Faulty brazing in second-stage engine cooling system caused engine burn through and cable damage resulting in shutdown midway through the upper stage's second burn, leaving spacecraft in elliptical LEO instead of GTO. Spacecraft thrusters raised orbit enough to complete some communications experiments.
F8 November 15, 1999
H-II Yoshinobu Launch Complex MTSAT (Multi-functional Transport Satellite) GEO Failure
Cavitation in the first stage hydrogen turbopump impeller caused an impeller blade to fracture, resulting in loss of fuel and rapid shutdown of the engine at T+239 s. The vehicle impacted the ocean 380 km NW of Chichi-jima.


See also


  1. ^ a b "H-II Launch Vehicle No.4" (Press release). NASDA. Archived from the original on 11 December 2003. Retrieved 2007-06-25.
  2. ^ a b JAXA. "H-II Launch Vehicle". Launch Vehicles and Space Transportation Systems. JAXA Website. Archived from the original on 2013-10-30. Retrieved 2007-06-25.
  3. ^ "About H-II Launch Vehicle". JAXA. Retrieved 12 December 2022.
  4. ^ Leslie Helm (1992-07-13). "Japan Discovers It's Harder to Be a Star in Space : Aerospace: The failure of a new rocket sets back its effort to become a key player in the commercial launch business". Los Angeles Times. Retrieved 2021-05-19.
  5. ^ "Hughes cancels NASDA rocket deal". The Japan Times. 2000-05-26. Retrieved 2021-05-14.