The H3 Launch Vehicle is an expendable launch system in development in Japan. Each H3 booster configuration has a two-digit and a 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 solid boosters are symmetrical. The letter in the end shows the length of the payload fairing, either short "S" or long "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.
Mitsubishi Heavy Industries, Ltd. is a Japanese multinational engineering, electrical equipment and electronics company headquartered in Tokyo, Japan. MHI is one of the core companies of the Mitsubishi Group. MHI's products include aerospace components, air conditioners, aircraft, automotive components, forklift trucks, hydraulic equipment, machine tools, missiles, power generation equipment, printing machines, ships and space launch vehicles. Through its defense-related activities, it is the world's 23rd-largest defense contractor measured by 2011 defense revenues and the largest based in Japan.