H-IIB

H-IIB Flight 8 at the launch pad in September 2019
Function	Medium-lift launch vehicle
Manufacturer	Mitsubishi Heavy Industries
Country of origin	Japan
Cost per launch	US$112.5 million[1]
Size
Height	56.6 m (185 ft 8 in)
Mass	531,000 kg (1,171,000 lb)
Stages	2
Capacity
Payload toLEO
Mass	19,000 kg (42,000 lb)[2]
Payload toISS (carrying the HTV)
Mass	16,500 kg (36,400 lb)[3]
Payload toGTO
Mass	8,000 kg (18,000 lb)[4]
Associated rockets
Family	H-II family
Based on	H-IIA
Derivative work	H3
Comparable	Ariane 5 Atlas V Falcon 9 Proton-M
Launch history
Status	Retired
Launch sites	Tanegashima,LA-Y2
Total launches	9
Success(es)	9
First flight	10 September 2009
Last flight	20 May 2020
Carries passengers or cargo	H-II Transfer Vehicle
Boosters –SRB-A3
No. boosters	4
Height	15.1 m (49 ft 6 in)
Diameter	2.5 m (8 ft 2 in)
Gross mass	76,500 kg (168,700 lb) each
Propellant mass	66,000 kg (146,000 lb) each
Maximum thrust	2,305 kN (518,000 lbf) each
Total thrust	9,220 kN (2,070,000 lbf)
Specific impulse	283.6 s (2.781 km/s)
Burn time	116 seconds
Propellant	HTPB
First stage
Height	38 m (124 ft 8 in)
Diameter	5.2 m (17 ft 1 in)
Gross mass	202,000 kg (445,000 lb)
Propellant mass	177,800 kg (392,000 lb)
Powered by	2 ×LE-7A
Maximum thrust	2,196 kN (494,000 lbf)
Specific impulse	440 seconds (4.3 km/s)
Burn time	352 seconds
Propellant	LH2 /LOX
Second stage
Height	11 m (36 ft 1 in)
Diameter	4 m (13 ft 1 in)
Gross mass	20,000 kg (44,000 lb)
Propellant mass	16,600 kg (36,600 lb)
Powered by	1 ×LE-5B
Maximum thrust	137 kN (31,000 lbf)
Specific impulse	448 s (4.39 km/s)
Burn time	499 seconds
Propellant	LH2 /LOX
[edit on Wikidata]

TheH-IIB (H2B) was a Japaneseexpendable launch system jointly developed byJAXA andMitsubishi Heavy Industries. It was used exclusively to launch theH-II Transfer Vehicle (HTV, orKōnotori) cargo spacecraft to theInternational Space Station.

The H-IIB was a two-stage rocket powered byliquid hydrogen andliquid oxygen (hydrolox) engines, with four strap-onsolid rocket boosters, and was launched from theTanegashima Space Center in southern Japan. It could deliver up to 8,000 kg (18,000 lb) togeostationary transfer orbit (GTO), compared with 4,000–6,000 kg (8,800–13,200 lb) for its predecessor, theH-IIA. Its performance tolow Earth orbit (LEO) was sufficient to carry the 16,500 kg (36,400 lb) HTV.^[4]

The H-IIB made its debut in September 2009 and flew nine times through May 2020, all successfully.^[4]

The H-IIB was a space launch vehicle jointly designed, manufactured and operated byJAXA andMitsubishi Heavy Industries to launch theH-II Transfer Vehicle. The system was designed to adopt methods and components that have already been verified by flights on theH-IIA, so that manufacturing the new launch vehicle would be more cost-effective, with less risk, in a shorter period of time. JAXA was in charge of preliminary design, readiness of the ground facility, and the development of new technologies for the H-IIB, in which the private sector has limited competencies, while the Mitsubishi Heavy Industries was responsible for manufacturing. JAXA successfully conducted eight firing tests of the new cluster design with the simulated first-stage propulsion system, called Battleship Firing Tests, since March 2008, at MHI's Tashiro Test Facility inŌdate,Akita Prefecture.^[5]

Before launch, two Captive Firing Tests were conducted on the H-IIB. The first test, which consisted of firing the first stage for ten seconds, was originally scheduled to occur at 02:30UTC on 27 March 2009, however it was cancelled after the launch pad's coolant system failed to activate.^[6] This was later discovered to have been due to a manual supply valve not being open.^[7] The test was rescheduled for 1 April 2009, but then postponed again due to a leak in a pipe associated with the launch facility's fire suppression system.^[8] The test was rescheduled for 2 April 2009,^[9] when it was successfully conducted at 05:00 UTC.^[10] Following this, the second test, which involved a 150-second burn of the first stage, was scheduled for 20 April.^[11] This was successfully conducted at 04:00 UTC on 22 April 2009,^[12] following a two-day delay due to unfavorable weather conditions.^[13] A ground test, using abattleship mockup of the rocket was subsequently conducted on 11 July 2009.^[14]

By 2009, the development program of the H-IIB had cost approximately 27 billion yen.^[15]

The H-IIB launch vehicle was a two-stage rocket. The first stage usedliquid oxygen andliquid hydrogen as propellants and had four strap-onsolid rocket boosters (SRB-A3) powered bypolybutadiene. The first stage was powered by twoLE-7A engines, instead of one for theH-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 singleLE-5B engine, which was also propelled by a hydrogen/oxygen fuel and oxidizer.^[16]

The first launch of the H-IIB occurred on 10 September 2009 at 17:01:46 UTC. It successfully launched theHTV-1, which was on a mission to resupply theInternational Space Station (ISS).^[17]

• Comparison of orbital launchers families
• Comparison of orbital launch systems

• JAXA | H-IIB Launch VehicleArchived 26 March 2014 at theWayback Machine
• "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

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