N-II (rocket)

{{Short description|Space launch vehicle}}

{{Infobox Rocket

|image=N-II.svg

|caption = The N-II rocket

|function = Carrier rocket

|manufacturer = McDonnell Douglas (design)
Mitsubishi Heavy Industries (production)

|country-origin = United States (design)
Japan (production)

|height = {{convert|35|m|ft}}

|diameter = {{convert|2.44|m|ft}}

|mass = {{convert|132690|kg|lb}}

|stages = 2 or 3

|capacities =

{{Infobox Rocket/Payload

|location = LEO

|kilos = {{convert|2000|kg|lb}}

}}

{{Infobox Rocket/Payload

|location = GTO

|kilos = {{convert|730|kg|lb}}

}}

|family = Delta

|status = Retired

|sites = Tanegashima, Osaki

|launches = 8

|success = 8

|first = 11 February 1981

|last = 19 February 1987

|stagedata =

{{Infobox Rocket/Stage

|type = booster

|name = Castor 2

|number = 9

|engines = 1 TX-354-3

|thrust = {{convert|258.9|kN|lbf}}

|SI = 262 sec

|burntime = 37 seconds

|fuel = Solid

}}

{{Infobox Rocket/Stage

|type = stage

|stageno = First

|name = Thor-ELT

|engines = 1 MB-3-3

|thrust = {{convert|866.7|kN|lbf}}

|SI = 290 sec

|burntime = 270 seconds

|fuel = RP-1/LOX

}}

{{Infobox Rocket/Stage

|type = stage

|name = Delta-F

|stageno = Second

|engines = 1 AJ-10-118F

|thrust = {{convert|41.3|kN|lbf}}

|SI = 280 sec

|burntime = 335 seconds

|fuel = HNO₃/UDMH

}}

{{Infobox Rocket/Stage

|type = stage

|name = Star-37E

|stageno = Third

|diff = optional

|engines = 1 solid

|thrust = {{convert|68|kN|lbf}}

|SI = 284 sec

|burntime = 42 seconds

|fuel = Solid

}}

{{Infobox Rocket/Stage

|type = stage

|name = Burner-2

|stageno = Third

|diff = alternative, optional

|engines = 1 solid

|thrust = {{convert|43.6|kN|lbf}}

|SI = 285 sec

|burntime = 42 seconds

|fuel = Solid

}}

}}

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.