N-II (rocket)

The N-II or N-2 was a derivative of the American Delta rocket, produced under licence in Japan. It replaced the N-I-rocket in Japanese use. It used a Thor-ELT first stage, a Delta-F second stage, nine Castor SRMs, and on most flights either a Star-37E or Burner-2 upper stage, identical to the US Delta 0100 series configurations. Eight were launched between 1981 and 1987, before it was replaced by the H-I, which featured Japanese-produced upper stages. All eight launches were successful.

N-II

The N-II rocket
Function	Carrier rocket
Manufacturer	McDonnell Douglas (design) Mitsubishi Heavy Industries (production)
Country of origin	United States (design) Japan (production)
Size
Height	35 metres (115 ft)
Diameter	2.44 metres (8.0 ft)
Mass	132,690 kilograms (292,530 lb)
Stages	2 or 3
Capacity
Payload to LEO
Mass	2,000 kilograms (4,400 lb)
Payload to GTO
Mass	730 kilograms (1,610 lb)
Associated rockets
Family	Delta
Launch history
Status	Retired
Launch sites	LA-N, Tanegashima
Total launches	8
Success(es)	8
First flight	11 February 1981
Last flight	19 February 1987
Boosters – Castor 2
No. boosters	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 – Delta-F
Engines	1 AJ-10-118F
Thrust	41.3 kilonewtons (9,300 lbf)
Specific impulse	280 sec
Burn time	335 seconds
Fuel	HNO3/UDMH
Third stage (optional) – Star-37E
Engines	1 solid
Thrust	68 kilonewtons (15,000 lbf)
Specific impulse	284 sec
Burn time	42 seconds
Fuel	Solid
Third stage (alternative, optional) – Burner-2
Engines	1 solid
Thrust	43.6 kilonewtons (9,800 lbf)
Specific impulse	285 sec
Burn time	42 seconds
Fuel	Solid