N-I (rocket)

The N-I or N-1 was a derivative of the American Thor-Delta rocket, produced under licence in Japan. It used a Thor-ELT first stage, a Mitsubishi Heavy Industries-designed LE-3 engine was used as a second stage,[3][4][5] and three Castor SRMs.[2][6] 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.

N-I

The N-I rocket[1]
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)[1]
Diameter	2.44 metres (8.0 ft)
Mass	131,330 kilograms (289,530 lb)[1]
Stages	2 or 3
Capacity
Payload to LEO	1,200 kilograms (2,600 lb)[1]
Payload to GTO	360 kilograms (790 lb)[1]
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[2]
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-3
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

Mock up of N-1

On 29 February 1976, the second N-I conducted the only orbital launch to occur on a leap day.[7]