H-I

H-I

H-I rocket
Function	Carrier rocket
Manufacturer	McDonnell Douglas (design) Mitsubishi Heavy Industries (production)
Country of origin	Japan (production) United States (design)
Size
Height	42 metres (138 ft)
Diameter	2.44 metres (8.0 ft)
Mass	142,260 kilograms (313,630 lb)
Stages	2 or 3
Capacity
Payload to LEO	3,200 kilograms (7,100 lb)
Payload to GTO	1,100 kilograms (2,400 lb)
Associated rockets
Family	Thor
Comparable	Delta 3000, PSLV
Launch history
Status	Retired
Launch sites	LA-N, Tanegashima
Total launches	9
Successes	9
First flight	12 August 1986
Last flight	11 February 1992
Boosters - Castor 2
No. boosters	6 or 9
Engines	1 TX-354-3
Thrust	258.9 kilonewtons (58,200 lbf)
Specific impulse	262 sec
Burn time	37 seconds
Fuel	Solid
First stage - Thor-ELT
Engines	1 MB-3-3
Thrust	866.7 kilonewtons (194,800 lbf)
Specific impulse	290 sec
Burn time	270 seconds
Fuel	RP-1/LOX
Second stage
Engines	1 LE-5
Thrust	102.9 kilonewtons (23,100 lbf)
Specific impulse	450 sec
Burn time	370 seconds
Fuel	LH2/LOX
Third stage (optional)
Engines	1 UM-129A
Thrust	77.4 kilonewtons (17,400 lbf)
Specific impulse	291 sec
Burn time	68 seconds
Fuel	Solid

The H–I or H–1 was a Japanese liquid-fuelled carrier rocket, consisting of a licence-produced American first stage and set of booster rockets, and all-Japanese upper stages. It was launched nine times between 1986 and 1992. It replaced the N-II, and was subsequently replaced by the H–2, 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. On launches to Geosynchronous transfer orbits, a Nissan–built UM-129A 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

Date/Time (GMT)	S/N	Payload	Orbit	Remarks
12 August 1986, 20:45	15(F)	EGP (Ajisai)	LEO	9 SRMs, 2 stages
27 August 1987, 09:20	17(F)	ETS-5 (Kiku-5)	GTO	9 SRMs, 3 stages
19 February 1988, 10:05	18(F)	CS-3A (Sakura-3A)	GTO	9 SRMs, 3 stages
16 September 1988, 09:59	19(F)	CS-3B (Sakura-3B)	GTO	9 SRMs, 3 stages
5 September 1989, 18:11	20(F)	GMS-4 (Himawari-4)	GTO	6 SRMs, 3 stages
7 February 1990, 01:33	21(F)	MOS-1B (Momo-1B)	LEO	9 SRMs, 2 stages
28 August 1990, 09:05	22(F)	BS-3A (Yuri-3A)	GTO	9 SRMs, 3 stages
25 August 1991, 08:40	23(F)	BS-3B (Yuri-3B)	GTO	9 SRMs, 3 stages
11 February 1992, 01:50	24(F)	JERS-1 (FUYO-1)	LEO	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