Sasha Tim wrote:

This entire satellite runs on an Atmega328...

You can do a lot with just a little, the Atmaga 328 compares favorably to the computers that took US astronauts to the moon in many ways. Roughly the same memory and computing power, plus the '328 consumes orders of magnitude less space, power, weight and dollars. Saturn and Apollo computers likely were better in radiation resistance and reliability though.

AMSAT used radiation hardened RCA COSMAC 1802 on several spacecraft, and I think one is still running on UO-11. That thing ran very slow, with a machine cycle of about 100 kHz, with opcodes taking 2 or 3 cycles to complete.

de KM1P Joe