| RT-21 Temp 2S|
|Type||Intercontinental ballistic missile|
|Designer||Alexander Nadiradze (Moscow Institute of Thermal Technology)|
|Manufacturer||Votkinsk Machine Building Plant|
|Warhead||Single 0.65-1.5 Mt warhead|
|Engine||Three stage, solid-propellant|
|Accuracy||450-1640 m CEP|
|Mobile launcher vehicle|
The RT-21 Temp 2S was a mobile intercontinental ballistic missile developed by the Soviet Union during the Cold War. It was assigned the NATO reporting name SS-16 Sinner and carried the industry designation 15Zh42.
The RT-21 was the first mobile ICBM developed in the world. Its innovative concept and design were created by Alexander Nadiradze. The RT-21M Pioner and succeeding missile complexes relied on the RT-21 base concept and were used by Nadiradze for many of his later projects. The program became mired in a series of treaty complications, including questions regarding its use of theatre missile launchers. It is unlikely that the RT-21 ultimately reached deployment, and by the mid-1980s, the program had been scrapped. Its maximum period of storage on a launcher was 5 years, and preparation time for launch was 40 minutes.