The 1802 (actually, a specialized version of the architecture) was the first CPU to leave the solar system (if it's a deep space probe from the 70's or 80's, it probably had an 1802 onboard).

It also ran the probe that was sent and crashed (intentionally!) into Venus. A friend who worked at GE at the time was on the design team. The thing that really impressed them was that the probe continued operating after landing, for something like a half hour, before melting...

See also:

• Harris Semiconductor still sells the 1802A and an 1805AC with timer/counter