Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
H3 (rocket)
The H3 rocket is a Japanese medium-lift launch vehicle developed by the Japan Aerospace Exploration Agency (JAXA) and Mitsubishi Heavy Industries (MHI). It is the successor to the H-IIA and H-IIB rockets, designed to reduce launch costs through the use of the lower-cost LE-9 main engine. The H3 features a modular design with two or three first-stage engines and zero, two, or four solid rocket boosters, allowing it to accommodate a variety of payload sizes. Development began in 2013, and the first flight took place in March 2023; the launch ended in failure when the second-stage engine did not ignite. The first successful test flight occurred in February 2024.
MHI oversaw development and leads final assembly of the H3 and its liquid-fuel engines. IHI Corporation produces the liquid-fuel engine turbopumps and solid-fuel boosters, Kawasaki Heavy Industries builds the S and L-type payload fairings, and Toray Industries supplies the carbon fiber and synthetic resin used in the booster motor cases and fairings. Beyond Gravity manufactures the W-type fairing based on its standard 5.4-metre-wide (18 ft) design.
The Japanese government authorized development of the H3 on 17 May 2013. The vehicle is being jointly developed by JAXA and MHI to support a wide range of commercial satellite launches. Compared with the H-IIA, the H3 was designed with simpler, lower-cost engines to reduce manufacturing time, technical risk, and overall expense. JAXA and MHI were responsible for preliminary design work, ground facility readiness, new technology development, and manufacturing. Cost reduction was the primary design goal, with launch prices projected at about US$37 million.
As of 2015, the first H3 launch was planned for Japanese fiscal year (JFY) 2020 in the H3-30 configuration, which lacks solid rocket boosters, followed by a booster-equipped version in JFY21.
The newly developed LE-9 engine was the key to cost reduction, improved safety, and higher thrust. The engine employs an expander bleed cycle, a combustion method previously used on the upper-stage LE-5 engine, and never before used on a first-stage. While such cycles typically cannot produce high thrust, the LE-9 was designed to reach 1,471 kN (331,000 lbf), making its development one of the most significant challenges of the program.
Ground tests of the LE-9 began in April 2017, and the first solid rocket booster tests were conducted in August 2018.
On 21 January 2022, the first H3 launch was postponed to JFY22 or later due to technical issues with the LE-9 engine.
The first launch attempt on 17 February 2023 was aborted just before ignition of the SRB-3 boosters, although the main engines had successfully ignited. The second launch attempt occurred on 7 March 2023 at 01:37:55 UTC. Approximately five minutes and twenty-seven seconds after launch, the second-stage engine failed to ignite. With the rocket unable to reach the required velocity, JAXA issued a self-destruct command 14 minutes and 50 seconds after launch, destroying the ALOS-3 satellite along with the launch vehicle.
Hub AI
H3 (rocket) AI simulator
(@H3 (rocket)_simulator)
H3 (rocket)
The H3 rocket is a Japanese medium-lift launch vehicle developed by the Japan Aerospace Exploration Agency (JAXA) and Mitsubishi Heavy Industries (MHI). It is the successor to the H-IIA and H-IIB rockets, designed to reduce launch costs through the use of the lower-cost LE-9 main engine. The H3 features a modular design with two or three first-stage engines and zero, two, or four solid rocket boosters, allowing it to accommodate a variety of payload sizes. Development began in 2013, and the first flight took place in March 2023; the launch ended in failure when the second-stage engine did not ignite. The first successful test flight occurred in February 2024.
MHI oversaw development and leads final assembly of the H3 and its liquid-fuel engines. IHI Corporation produces the liquid-fuel engine turbopumps and solid-fuel boosters, Kawasaki Heavy Industries builds the S and L-type payload fairings, and Toray Industries supplies the carbon fiber and synthetic resin used in the booster motor cases and fairings. Beyond Gravity manufactures the W-type fairing based on its standard 5.4-metre-wide (18 ft) design.
The Japanese government authorized development of the H3 on 17 May 2013. The vehicle is being jointly developed by JAXA and MHI to support a wide range of commercial satellite launches. Compared with the H-IIA, the H3 was designed with simpler, lower-cost engines to reduce manufacturing time, technical risk, and overall expense. JAXA and MHI were responsible for preliminary design work, ground facility readiness, new technology development, and manufacturing. Cost reduction was the primary design goal, with launch prices projected at about US$37 million.
As of 2015, the first H3 launch was planned for Japanese fiscal year (JFY) 2020 in the H3-30 configuration, which lacks solid rocket boosters, followed by a booster-equipped version in JFY21.
The newly developed LE-9 engine was the key to cost reduction, improved safety, and higher thrust. The engine employs an expander bleed cycle, a combustion method previously used on the upper-stage LE-5 engine, and never before used on a first-stage. While such cycles typically cannot produce high thrust, the LE-9 was designed to reach 1,471 kN (331,000 lbf), making its development one of the most significant challenges of the program.
Ground tests of the LE-9 began in April 2017, and the first solid rocket booster tests were conducted in August 2018.
On 21 January 2022, the first H3 launch was postponed to JFY22 or later due to technical issues with the LE-9 engine.
The first launch attempt on 17 February 2023 was aborted just before ignition of the SRB-3 boosters, although the main engines had successfully ignited. The second launch attempt occurred on 7 March 2023 at 01:37:55 UTC. Approximately five minutes and twenty-seven seconds after launch, the second-stage engine failed to ignite. With the rocket unable to reach the required velocity, JAXA issued a self-destruct command 14 minutes and 50 seconds after launch, destroying the ALOS-3 satellite along with the launch vehicle.