8. RCA COSMAC CDP 1802 (1976)
Breakthrough application: NASA Voyager 1 (1977)
The RCA 1802 was the first microprocessor in space. Due to RCA's aggressive positioning of the 1802 in the late 1970s, the chip made its way into numerous probes and satellites--most notably the Viking, Galileo, and Voyager missions. Its low power consumption and a readily available radiation-hardened version made it ideal for the harsh conditions beyond Earth's atmosphere.
Voyager 1, which carries three 1802 processors, is currently 10.2 billion miles from Earth, making it the most distant man-made object. It left our solar system long ago and is hurtling toward interstellar space, where it may someday catch the eye of an extraterrestrial civilization.
If alien engineers do find Voyager 1, they could learn everything about Earth's computer systems by reverse-engineering the 1802, which would have to make it more influential than all of the other CPUs on this list combined. What could be bigger than a processor that shapes an alien culture's view of our civilization?
Photos: CPU-World.com, NASA