H3

The H3 is a Japanese medium-lift launch vehicle developed by JAXA and Mitsubishi Heavy Industries, a hydrolox-fuelled rocket that succeeds the H-IIA and H-IIB. It uses the LE-9 main engine, designed to be cheaper to produce as part of an effort to lower launch costs, and has a modular design with two or three LE-9 engines in the first stage and zero, two or four SRB-3 solid boosters. Its second stage uses the LE-5B-3 engine. Development began in 2013, with Mitsubishi Heavy Industries as prime contractor. The maiden flight in March 2023 failed when the second-stage engine did not ignite, and the first successful flight came in February 2024. It also launches the HTV-X cargo spacecraft to the International Space Station.