H-IIB (H2B)

H-IIB (H2B) is a launch system used to launch H-II Transfer Vehicles towards the International Space Station. H2B rockets are launched from the Tanegashima Space Center in Japan. H-IIB is built by Mitsubishi Heavy Industries.  H-IIB is derived from the original H-II and the H-IIA that underwent  modifications to reduce costs and increase reliability and to increase its payload capacity for the heavy HTV. The H-IIB was designed to adopt methods and components that have already been verified by flights on the H-IIA, so that manufacturing the new launch vehicle would be more cost-effective, with less risk, in a shorter period of time.

 

The H-IIB rocket  has a liftoff mass of 531tonnes  and is 56.6 Meters high.   Unlike H-IIA, the H-IIB has an increased first stage diameter of 5.2 meters. The H-IIB launch vehicle is a two-stage rocket. first stage uses liquid oxygen and liquid hydrogen as propellants and has four strap-on solid rocket boosters.  The first stage is powered by two LE-7A engines . It can lift payloads of up to 19,000 kilograms to Low Earth Orbit  and  8,000 Kilograms to Geostationary Transfer Orbit. One LE-5B engine powers the vehicle during second stage flight. The Engine is 2.79 meters in Diameter and has a nozzle diameter of 2.49 meters. Le-5B provides 137 Kilonewtons of thrust. It has a nominal burn time of 499 seconds, but is certified to burn for up to 40 minutes.