N-I (rocket)

N-I

The N-I rocket
Function	Carrier rocket
Manufacturer	McDonnell Douglas (design) Mitsubishi Heavy Industries (production)
Country of origin	United States (design) Japan (production)
Size
Height	34 metres (112 ft)
Diameter	2.44 metres (8.0 ft)
Mass	131,330 kilograms (289,530 lb)
Stages	2 or 3
Capacity
Payload to LEO	1,200 kilograms (2,600 lb)
Payload to GTO	360 kilograms (790 lb)
Associated rockets
Family	Delta
Launch history
Status	Retired
Launch sites	LA-N, Tanegashima
Total launches	7
Successes	6
Partial failures	1
First flight	9 September 1975
Last flight	3 September 1982
Boosters - Castor 2
No. boosters	3
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
Thrust	52.9 kilonewtons (11,900 lbf)
Specific impulse	290 sec
Burn time	246 seconds
Fuel	NTO/A-50
Third stage (optional) - Star-37N
Engines	1 solid
Thrust	45 kilonewtons (10,000 lbf)
Specific impulse	290 sec
Burn time	42 seconds
Fuel	Solid

The N-I or N-1 was a derivative of the American Delta rocket, produced under licence in Japan. It used a Thor-ELT first stage, a Mitsubishi Heavy Industries-designed engine was used as a second stage, and three Castor SRMs. Seven were launched between 1975 and 1982, before it was replaced by the N-II. Six of the seven launches were successful, however on the fifth flight, there was recontact between the satellite and the third stage, which caused the satellite to fail.

On 29 February 1976, the second N-I conducted the only orbital launch to occur on a leap day (as of year 2008).