|Function||Medium-lift launch vehicle|
|Manufacturer||Mitsubishi Heavy Industries|
|Country of origin||Japan|
|Cost per launch||US$50 million (H3-303S)|
|Height||63 m (207 ft) |
|Diameter||5.27 m (17.3 ft)|
|Mass||574,000 kg (1,265,000 lb) (Gross for H3-24L Variant)|
|Payload to SSO|
|Mass||4000 kg (H3-30S/L) |
|Payload to GTO|
|Mass||4,000–7,900 kg (8,800–17,400 lb)(H3-24S/L)|
|Status||Currently being manufactured|
|Launch sites||Tanegashima, LA-Y|
|First flight||2021 (planned)|
|No. boosters||0, 2 or 4|
|Thrust||2,158 kN (485,000 lbf)|
|Specific impulse||283.6 seconds (2.781 km/s)|
|Burn time||105 seconds|
|Engines||2 or 3 LE-9|
|Thrust||2,942, or 4,413 kN (661,000, or 992,000 lbf)|
|Specific impulse||425 seconds (4.17 km/s)|
|Fuel||LH2 / LOX|
|Thrust||137 kN (31,000 lbf)|
|Specific impulse||448 seconds (4.39 km/s)|
|Fuel||LH2 / LOX|
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 Tanegashima Space Center in Japan. Mitsubishi and JAXA are responsible for the design, manufacture, and operation of the H3.
As of July 2015[update], the minimum configuration is to carry a payload of up to 4000 kg into sun-synchronous orbit for about 5 billion yen, and the maximum configuration is to carry more than 6500 kg into geostationary transfer orbit. The H3-24 variant will deliver more than 6000 kg of payload to lunar transfer orbit.
The development of the H3 was authorized by the Japanese government on 17 May 2013. The H3 Launch Vehicle is being jointly developed by JAXA and Mitsubishi Heavy Industries (MHI) to launch a wide variety of commercial satellites. The H3 was designed with cheaper engines compared to the H-IIA, so that manufacturing the new launch vehicle would be faster, less risky, and more cost-effective. JAXA and Mitsubishi Heavy Industries were in charge of preliminary design, the readiness of ground facilities, development of new technologies for the H3, and manufacturing. The main emphasis in design is cost reduction, with planned launch costs for customers in the range of US$50−65 million.[better source needed]
The newly developed LE-9 engine is the most important factor in achieving both cost reduction and improved safety and thrust simultaneously. The expander bleed cycle used in the LE-9 engine is a highly reliable combustion method that Japan has put into practical use for the LE-5A/B engine. However, in principle, it is not suitable for large thrust and there is no precedent, so the development of the LE-9 engine with a large thrust of 1,471 kN is the most challenging and important development element.
In earlier plans, the first H3 was to be launched in fiscal year 2020 in the H3-30 configuration which lacks solid-rocket boosters, and in a later configuration with boosters in FY2021.
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-A) using polybutadiene fuel. The first stage is powered by two or three LE-9 engines which uses an expander bleed cycle design similar to the LE-5B engine. The fuel and oxidizer mass of the first stage is 225 metric tons. The second stage is powered by a single engine which is an improved LE-5B. The propellant mass of the second stage is 23 metric tons.
Each H3 booster configuration has a two-digit plus 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 the solid boosters are symmetrical. The letter at the end shows the length of the payload fairing, either short, or "S", or long, or "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.
As of November 2018[update], three configurations are planned: H3-30, H3-22, and H3-24.
A previously mentioned variant, the H3-32, was cancelled in late 2018 when the performance of the H3-22 variant, sporting one less engine on the core booster, was found to be greater than anticipated, putting it close to the H3-32's performance. While the H3-32 would have provided greater performance, JAXA cited SpaceX's experience with their Falcon 9 rocket, which routinely lifted commercial communications satellite payloads to less than the gold standard geosynchronous transfer orbit of 1500 m/s of delta-V remaining to get to geostationary orbit, leaving the satellites themselves to make up the difference. As commercial clients were apparently willing to be flexible, JAXA proposed redefining their reference transfer orbit to something lower, believing commercial clients would prefer the less expensive (if slightly less capable) H3-22 rocket, even if the client had to then load additional propellant onto their satellite for it to reach GEO, than a more expensive H3-32.
As of October 2019[update], MHI is considering contributing two variants for the Lunar Gateway project: an extended second stage variant, and the H3 Heavy variant which would comprise three first-stage liquid-fuel boosters strapped together, similar to Delta IV Heavy and Falcon Heavy. It would have a payload capacity of 28,300 kg to low earth orbit.
H3 will have a "dual-launch capability, but MHI is focused more on dedicated launches" in order to prioritize schedule assurance for customers.
|Date and time (UTC)||Flight||Type||Launch site||Payload(s)||Outcome|
|2021 (TBD)||TF1||H3-22S||LP2, Tanegashima||ALOS-3||Planned|
|2022 (TBD)||TF2||H3||LP2, Tanegashima||ALOS-4||Planned|
|2023 (TBD)||H3||Lunar Polar Exploration Mission||Planned|
|2025 (TBD)||H3||IGS-Optical 9||Planned|
|2027 (TBD)||H3||ALOS-3 Successor||Planned|
|2028 (TBD)||H3||IGS-Radar 9||Planned|
|2028 (TBD)||H3||ALOS-4 Successor||Planned|
|2029 (TBD)||H3||Himawari Successor||Planned|
|2029 (TBD)||H3||IGS-Optical 10||Planned|
|2029 (TBD)||H3||IGS-Radar 10||Planned|
H3 is on track for a 2020 debut with a price meant to be on par with SpaceX's Falcon 9.
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