The R-2 rocket (NATO reporting name SS-2 Sibling, Soviet code 8Zh38) was developed based on R-1 design. This was an improved version of the German V-2 rocket manufactured by the Soviet Union. The R-1 was quickly followed by an evolutionary improvement, the R-2 (SS-2), which had a longer range and at least four major differences in design. The weight was increased by 50%, but the range was more than doubled, to . R-2 had the following major differences from the R-1's (and hence from the V-2's) design: