H3 (rocket)

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Function Launch vehicle
Manufacturer Mitsubishi Heavy Industries
Country of origin Japan
Height 63 m[1]
Diameter 5.2 m[1]
Mass 574,000 kg (1,265,000 lb)[2]
Stages 2
Payload to
GTO ⊿V=1500m/s
> 6,500 kg (14,300 lb)[1]
Launch history
Status In development
Launch sites LA-Y, Tanegashima
First flight FY2020 (planned)[1]
No. boosters 0, 2 or 4
Engines SRB-3
Thrust 2,158 kN (485,000 lbf)[2]
Specific impulse 283.6 s (2.781 km/s)
Burn time 105 s
Fuel Solid
First stage
Engines 2 or 3 LE-9
Thrust 1,472 kN (331,000 lbf)[2]
Specific impulse 425 seconds (4.17 km/s)
Fuel LOX/LH2
Second stage
Engines 1 LE-5B-3[2]
Thrust 137 kN (31,000 lbf)[2]
Specific impulse 448 seconds (4.39 km/s)
Fuel LOX/LH2

The H3 Launch Vehicle is an expendable launch system in development in Japan. H3 rockets are liquid-propellant rockets with strap-on solid rocket boosters and are planned to be launched from the Tanegashima Space Center in Japan. Mitsubishi and the JAXA have been primarily responsible for the design, manufacture, and operation of the H3.

As of July 2015, it is planned that the minimum configuration is to carry a payload of up to 4 tonnes into sun-synchronous orbit for about 5 billion yen, and the maximum configuration is to carry more than 6.5 tonnes into geostationary transfer orbit.[1]

The first H3 without boosters is planned to launch in fiscal year 2020, and with boosters in FY2021.[3][1]


The development of H3 was authorized by Japanese government 17 May 2013.[4] The H3 Launch Vehicle is being developed jointly by JAXA and Mitsubishi Heavy Industries to launch a wide variety of commercial satellites. H3 was designed with cheaper engines compared to H-IIA, so that manufacturing the new launch vehicle would be more cost-effective, with less risk, in a shorter period of time. JAXA was in charge of preliminary design, readiness of the ground facility, and development of new technologies for the H3, while Mitsubishi Heavy Industries is responsible for manufacturing. The main emphasis in design is cost reduction, with planned launch costs for customers are in range 50-65 mln USD.[5]

Vehicle description[edit]

The H3 Launch Vehicle is a two-stage rocket. The first stage uses liquid oxygen and liquid hydrogen as propellants and carries zero, two or four strap-on solid rocket boosters (derived from SRB-A3) powered by polybutadiene. The first stage is powered by two or three LE-9 engines which uses expander bleed cycle similar to LE-5B.[6] The second stage is powered by a single engine which is an improved LE-5B.[7][2]


Each H3 booster configuration has a two-digit and a letter designation that indicates the features of that configuration. The first digit represents the number of LE-9 engines on the main stage, either "2" or "3". The second digit indicates the number of SRB-3 solid rocket boosters attached to the base of the rocket, and can be "0", "2" or "4". All layouts of solid boosters are symmetrical. The letter in the end shows the length of the payload fairing, either short "S" or long "L". For example, an H3-24L has two engines, four solid rocket boosters, and a long fairing, whereas an H3-30S has three engines, no solid rocket boosters, and a short fairing.


External links[edit]