[5] As of July 2015[update], the minimum configuration is to carry a payload of up to 4,000 kg (8,800 lb) into Sun-synchronous orbit (SSO) for about 5 billion yen, and the maximum configuration is to carry more than 6,500 kg (14,300 lb) into geostationary transfer orbit (GTO).

[6][7] The carbon fiber and synthetic resin used for the solid fuel booster motor case and payload fairing were developed and manufactured by Toray.

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.

[Note 1][2] The newly developed LE-9 engine is the most important factor in achieving cost reduction, improved safety and increased thrust.

[13] 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.

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 1,500 m/s (4,900 ft/s) of delta-V remaining to get to geostationary orbit, leaving the satellites themselves to make up the difference.

[21] H3 will have a "dual-launch capability, but MHI is focused more on dedicated launches" in order to prioritize schedule assurance for customers.

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.