Engineering:H-I

For the molecule with molecular formula H-I, see hydrogen iodide.

Short description: Japanese liquid-fuelled carrier rocket

H-I

H-I rocket
Function	Medium-lift launch vehicle
Manufacturer	Mitsubishi Heavy Industries (production) McDonnell Douglas (design)
Country of origin	Japan (production) United States (design)
Size
Height	42 m (138 ft)
Diameter	2.44 m (8 ft 0 in)
Mass	142,260 kg (313,630 lb)
Stages	2 or 3
Capacity
Payload to LEO	3,200 kg (7,100 lb)
Payload to GTO	1,100 kg (2,400 lb)
Associated rockets
Family	Delta
Derivatives	H-II
Comparable	Delta 3000, PSLV
Launch history
Status	Retired
Launch sites	Tanegashima, Osaki
Total launches	9
Successes	9
First flight	12 August 1986
Last flight	11 February 1992
Boosters – Castor 2
No. boosters	6 or 9
Motor	1 × TX-354-3
Thrust	258.9 kN (58,200 lbf)
Specific impulse	262 s (2.57 km/s)
Burn time	37 seconds
Fuel	HTPB/Al
First stage – Thor-ELT
Engines	1 × MB-3-3
Thrust	866.7 kN (194,800 lbf)
Specific impulse	290 s (2.8 km/s)
Burn time	270 seconds
Fuel	RP-1/LOX
Second stage
Engines	1 × LE-5
Thrust	102.9 kN (23,100 lbf)
Specific impulse	450 s (4.4 km/s)
Burn time	370 seconds
Fuel	LH2/LOX
Third stage (optional)
Engines	1 × UM-129A
Thrust	77.4 kN (17,400 lbf)
Specific impulse	291 s (2.85 km/s)
Burn time	68 seconds
Fuel	Solid

The H–I (H–1) was a Japanese medium-lift launch vehicle, consisting of a licence-produced American first stage and set of booster rockets, and all-Japanese upper stages. The H in the name represented the use of liquid hydrogen fuel in the second stage. It was launched nine times between 1986 and 1992. It replaced the N-II, and was subsequently replaced by the H-II, which used the same upper stages with a Japanese first stage.

The first stage of the H–I was a licence-built version of the Thor-ELT, which was originally constructed for the US Delta 1000 rocket. The stage had already been produced under licence in Japan for the N-I and N-II rockets. The second stage was entirely Japanese, using an LE-5 engine, the first rocket engine in Japan to use a cryogenic fuel. On launches to Geosynchronous transfer orbits, a Nissan–built UM-69A solid motor was used as a third stage. Depending on the mass of the payload, either six or nine US Castor 2 SRMs were used as booster rockets.

Launch history

Flight No.	Date / time (UTC)	Rocket, Configuration	Launch site	Payload	Payload mass	Orbit	Customer	Launch outcome
F15	12 August 1986, 20:45	H-I	Tanegashima, Osaki	EGP (Ajisai)		LEO		Success
	9 SRMs, 2 stages
F17	27 August 1987, 09:20	H-I	Tanegashima, Osaki	ETS-5 (Kiku-5)		GTO		Success
	9 SRMs, 3 stages
F18	19 February 1988, 10:05	H-I	Tanegashima, Osaki	CS-3A (Sakura-3A)		GTO		Success
	9 SRMs, 3 stages
F19	16 September 1988, 09:59	H-I	Tanegashima, Osaki	CS-3B (Sakura-3B)		GTO		Success
	9 SRMs, 3 stages
F20	5 September 1989, 19:11	H-I	Tanegashima, Osaki	GMS-4 (Himawari-4)		GTO		Success
	6 SRMs, 3 stages
F21	7 February 1990, 01:33	H-I	Tanegashima, Osaki	MOS-1B (Momo-1B)		LEO		Success
	9 SRMs, 2 stages
F22	28 August 1990, 09:05	H-I	Tanegashima, Osaki	BS-3A (Yuri-3A)		GTO		Success
	9 SRMs, 3 stages
F23	25 August 1991, 08:40	H-I	Tanegashima, Osaki	BS-3B (Yuri-3B)		GTO		Success
	9 SRMs, 3 stages
F24	11 February 1992, 01:50	H-I	Tanegashima, Osaki	Japanese Earth Resource Satellite (FUYO-1)		LEO		Success
	9 SRMs, 2 stages

When the H–1 was announced in 1986, company representative Tsuguo Tatakawe clarified that it would only be used to launch indigenous (i.e. Japanese) payloads, that only two launches per year could be mounted, and that the launch window consisted of a four-month period in which Japanese fishing fleets were not active (the falling launch boosters may damage fishing nets in the ocean waters).

See also

• Delta rocket
• H-II
• H-IIA
• PGM-17 Thor
• Comparison of orbital launchers families
• Comparison of orbital launch systems

References

• Wade, Mark. "Delta". Encyclopedia Astronautica. http://www.astronautix.com/lvs/delta.htm. 
• McDowell, Jonathan. "Thor". Orbital and Suborbital Launch Database. Jonathan's Space Report. http://planet4589.org/space/lvdb/launch/Thor. 
• Krebs, Gunter. "H-1". Gunter's Space Page. http://space.skyrocket.de/doc_lau/h-1.htm.