for 20 April. This was successfully conducted at 04:00 UTC on 22 April 2009, following a two-day delay due to unfavorable weather conditions. A ground test, using a battleship mockup of the rocket was subsequently conducted on 11 July 2009. By 2009, the development program of the H-IIB had cost approximately 27 billion yen. Vehicle description The H-IIB launch vehicle was a two-stage rocket. The first stage used liquid oxygen and liquid hydrogen as propellants and had four strap-on solid rocket boosters (SRB-A3) powered by polybutadiene. The first stage was powered by two LE-7A engines, instead of one for the H-IIA. It had four SRB-As attached to the body, while the standard version of H-IIA had two SRB-As. In addition, the first-stage body of the H-IIB was 5.2 m in diameter compared with 4 m for the H-IIA. The total length of the first stage was extended by 1 m from that of H-IIA. As a result, the H-IIB first stage held 70% more propellant than that of the H-IIA. The second stage was powered by a single LE-5B engine, which was also propelled by a hydrogen/oxygen fuel and oxidizer. Launch history The first launch of the H-IIB occurred on 10 September 2009 at 17:01:46 UTC. It successfully launched the HTV-1, which was on a mission to resupply the International Space Station (ISS). See also Comparison of orbital launchers families Comparison of orbital launch systems References External links JAXA | H-IIB Launch Vehicle "Development Status of the H-IIB Launch Vehicle". Mitsubishi Heavy Industries Technical Review Volume 45 Number 4 H-2B rocket 3D model Mitsubishi Heavy Industries space launch vehicles Vehicles introduced in 2009 Expendable space launch systems