thumb|200px|right|Lambda 4S (replica) and the launcher as exhibited at [[National Museum of Nature and Science.]]
Lambda is the name of a family of Japanese carrier rockets. It consisted of the types Lambda 2, Lambda 3, Lambda 3H, Lambda 4S, Lambda 4SC, and Lambda 4T developed jointly by Institute of Industrial Science of the University of Tokyo, Institute of Space and Astronautical Science of the University of Tokyo, and Prince Motor Company, which merged with Nissan in 1966.
Lambda series rockets did not have guidance systems, as they had the potential to be converted for offensive military use, thus interpreted as a violation of Article 9 of the Japanese Constitution. However, future Japanese launch vehicles, such as the H-II, were allowed to have guidance systems.
Configurations
Lambda types differ regarding the upper stages used. The following table shows the actual configurations:
|-
|4S
| rowspan="3" |2 × SB-310
| rowspan="3" |L-480S
|
|-
|4SC
|
|-
|4T
|
|}
Launches
Lambda rockets were launched by ISAS, from Kagoshima pad L. A fourth-stage attitude control failed resulting in loss of the vehicle and payload.
{| class="wikitable sortable"
|+List of Lambda launches
!Date
!Version
!Apogee
!Mission
|-
|1963 August 24
|2
|
|Failure
|-
|1963 December 11
|2
|
|Ionosphere mission
|-
|1964 July 11
|3
|
|Ionosphere mission
|-
|1965 January 31
|3
|
|Ionosphere mission
|-
|1965 March 18
|3
|
|X-ray astronomy mission
|-
|1966 March 5
|3H
|
|X-ray astronomy mission
|-
|1966 July 23
|3H
|
|Gyro-plasma probe Ionosphere / aeronomy mission
|-
|1966 September 26
|4S
|
|Ohsumi launch attempt. Failure: Fourth stage attitude control failed
|-
|1966 December 20
|4S
|
|Ohsumi launch attempt. Failure: Fourth stage failed to ignite
|-
|1967 February 6
|3H
|
|Ionosphere / chemical release / x-ray astronomy mission
|-
|1967 April 13
|4S
|
|Ohsumi launch attempt. Failure: Fourth stage failed to ignite
|-
|1969 January 16
|3H
|
|Ionosphere mission
|-
|1969 September 3
|4T
|
|Test mission
|-
|1969 September 22
|4S
|
|Ohsumi launch attempt. Failure: Fourth stage control system malfunction after third stage collided with fourth stage
|-
|1970 January 21
|3H
|
|Ionosphere / plasma mission
|-
|1970 February 11
|4S
|
|Ohsumi (first successful satellite of Japan, fifth attempt of Lambda 4S)
|-
|1970 September 19
|3H
|
|X-ray / ultraviolet astronomy mission
|-
|1971 August 20
|4SC
|
|Failure
|-
|1971 September 3
|3H
|
|Aeronomy / ionosphere / x-ray astronomy mission
|-
|1973 January 28
|4SC
|
|TVC test
|-
|1974 January 22
|3H
|
|St 2: 329 km X-ray astronomy mission
|-
|1974 September 1
|4SC
|
|TVC test
|-
|1976 August 30
|4SC
|
|Radar transponder
|-
|1977 August 16
|3H
|
|Aeronomy / ionosphere / plasma mission
|-
|1979 September 20
|4SC
|
|TVC test
|}