As of July2015[update],the minimum H3-30 configuration is to carry a payload of up to 4,000kg (8,800lb) into Sun-synchronous orbit (SSO) for about ¥5 billion(equivalent to¥5.1 billionorUS$46.76 million in 2019)[6] and the maximum configuration is to carry more than 6,500kg (14,300lb) into geostationary transfer orbit (GTO).[2] The most powerful H3‑24 variant will deliver more than 6,000kg (13,000lb) of payload to lunar transfer orbit (TLI) and 8,800kg (19,400lb) of payload to geostationary transfer orbit (GTO) (∆V=1830m/s).
The development of the H3 was authorized by the Japanese government on 17 May 2013.[10] 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 around US$37 million.[11]
In 2015,the first H3 was planned 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.[Note 1][2]
The newly developed LE-9 engine is the most important factor in achieving cost reduction,improved safety and increased thrust. 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,it is physically difficult for an expander bleed cycle engine to generate large thrust,so the development of the LE-9 engine with a thrust of 1,471kN (331,000lbf) was the most challenging and important development element.[12]
Firing tests of the LE-9 first-stage engine began in April 2017,[13] with the first tests of the solid rocket boosters occurring in August 2018.[14]
On 21 January 2022,the launch of the first H3 was rescheduled to FY 2022 or later,citing technical problems regarding the first stage LE-9 engine.[15]
Vehicle description
The H3 Launch Vehicle is a two-stage launch vehicle. The first stage uses liquid oxygen and liquid hydrogen as propellants and carries zero,two or four strap-on solid rocket boosters (SRBs) (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.[16] 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.[3][17]
Variants
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.[18] W-type fairing is similar to L-type except wider 5.4 m diameter.[Note 2]
As of November2018[update],three configurations are planned:H3-30,H3-22,and H3-24.[18]
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 geostationary transfer orbit (GTO) of 1,500m/s (4,900ft/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.[18]
As of October2019[update],MHI is considering contributing two variants for the 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.[21] It would have a payload capacity of 28,300kg (62,400lb) to low Earth orbit.[22]
Launch services
H3 will have a "dual-launch capability,but MHI is focused more on dedicated launches" in order to prioritize schedule assurance for customers.[23]
As of 2018,MHI is aiming to price the H3 launch service on par with SpaceX's Falcon 9.[23]
The first launch attempt on 17 February 2023 was aborted just before the SRB-3 boosters ignition, although the main engines were successfully ignited.[33][34][35]
On the second launch attempt for the H3 Launch Vehicle on 7 March the vehicle launched at 1:37:55 AM UTC (Universal Time Coordinated). Shortly after the SRB-3 boosters separated from the rocket around two minutes into the flight, the rocket appeared to lose control and begin to tumble based on the views from the ground camera; however, based on subsequent analysis, this appears to be part of a planned dogleg maneuver in order to achieve sun-synchronous orbit and not in fact a loss of control.[36] Approximately five minutes and twenty-seven seconds after launch, the second stage engine failed to ignite. After continuing to be unable to confirm second stage engine ignition, and with the velocity of the rocket continuing to fall, JAXA sent a self-destruct command to the rocket at around L+ 00:14:50 because there was "no possibility of achieving the mission". The payload onboard was the ALOS-3 satellite, which was also destroyed with the launch vehicle on the moment of self-destruct.[37][38][39][40][41][42][43][44][45]
TF2
On 17 February 2024, JAXA finally successfully launched the second testing rocket which has the same configuration as the first one, H3-22S, and the second stage reached the desired orbit.[46]
On 4 November 2024 the $50 million H3 launch orbited DSN-3, also known as Kirameki 3, a geostationary communications satellite in the X band, to be used for Japanese military communications.[31]
↑ A Japanese Fiscal Year starts in April of the year and ends in March of the next year. For this case, it denotes launch will occur no earlier than 1 April 2021, and no later than 31 March 2022.
↑ W-type was mentioned in the description of JAXA's web page, but not in the current description as of November 2023[update].[19] Manufacturing of W-type fairing is contracted to RUAG Space (now Beyond Gravity), whereas other types are manufactured by Kawasaki Heavy Industries.[20]
↑ "H3ロケットの試験機1号機の打上げについて" (in Japanese). JAXA. 21 January 2022. Archived from the original on 2 December 2022. Retrieved 21 January 2022.
↑ "Development of the LE-X Engine"(PDF). Mitsubishi Heavy Industries Technical Review. 48 (4). December 2011. Archived(PDF) from the original on 9 July 2015. Retrieved 8 July 2015.
↑ 2020年：H3ロケットの目指す姿(PDF) (in Japanese). JAXA. 8 July 2015. Archived(PDF) from the original on 5 March 2016. Retrieved 8 July 2015.
1 2 3 H3ロケットの開発状況について(PDF) (in Japanese). JAXA. 29 November 2018. Archived(PDF) from the original on 29 November 2018. Retrieved 29 November 2018.
↑ 衛星フェアリングとは (in Japanese). JAXA. Archived from the original on 25 September 2022. Retrieved 25 September 2022.
↑ "宇宙基本計画⼯程表 (令和5年度改訂)"[Basic Plan on Space Policy (2023 Revision)](PDF) (in Japanese). Cabinet Office. 22 December 2023. p.45. Archived(PDF) from the original on 25 December 2023. Retrieved 26 December 2023.
↑ "H3ロケット試験機1号機による先進光学衛星「だいち3号」（ALOS-3）の打上げについて[再設定(その5)]"[Launch of Advanced Optical Satellite "DAICHI-3" (ALOS-3) by H3 Rocket Test Vehicle No. 1 [Reschedule (Part 5)]] (Press release) (in Japanese). JAXA. 4 March 2023. Archived from the original on 4 March 2023. Retrieved 4 March 2023.
↑ H3ロケットの開発状況について(PDF). 宇宙開発利用部会 (in Japanese). 10 December 2019. Archived(PDF) from the original on 10 December 2019. Retrieved 10 December 2019.
↑ "JAXA 主力ロケット「H3」2号機 2024年2月15日に打ち上げへ"[JAXA main rocket "H3" No. 2 to be launched on 15 February 2024]. NHK (in Japanese). 27 December 2023. Retrieved 27 December 2023.
↑ "「H3」ロケット3号機 種子島宇宙センターから打ち上げ成功"["H3" rocket No. 3 successfully launched from Tanegashima Space Center]. NHK (in Japanese). 1 July 2024. Retrieved 30 June 2024.
↑ Sato, Toshiaki (27 September 2024). H3ロケット30形態試験機の打上げ計画及び超小型衛星相乗りの実施について(PDF). Ministry of Education, Culture, Sports, Science and Technology (in Japanese). Retrieved 28 October 2024.
↑ "HTV-X1". Next Spaceflight. Retrieved 4 July 2025.
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