Cold War (1953–1962) human on the moon. The first of the Lunar missions was Luna 1, which launched on January 2, 1959. Its successful mission established the first rocket engine restart within Earth orbit and the first man-made object to establish heliocentric orbit. Luna 2, which launched on September 14, 1959, established the first impact into another celestial body (the moon). Finally, Luna 3 launched on October 7, 1959 and took the first pictures of the dark side of the moon. After these three missions in 1953, the Soviets continued their exploration of the moon and its environment in 21 other Luna missions.
Mega Man 2 series were defined by the first game, but "Mega Man 2" added crucial conventions that were retained for the rest of the series. The traditional number of Robot Masters for the series is eight as used in "Mega Man 2", rather than the six used in the original. It was the first in the series to include an opening cinematic. "Mega Man 2" also introduced the Energy Tank item, special movement items, teleporter room, and password system, which became staples in future games. The Energy Tank became the series' iconic health refill item and later served as inspiration for a