[VeilEm]

> because it's just not worth encrypting

That seems unlikely to be the reason but I don't know much about how satellites are programmed. On the terrestrial plane a $5 raspberry pi with free software can encrypt and decrypt secure communication. It's trivial and cheap to encrypt.

[jjoonathan]

Raspi isn't rad-hardened and wouldn't last long (about a month is typical if memory serves). Still, rad-hardening a processor wouldn't exactly be the hardest part of the project so the point stands.

[mschuster91]

Just wrap it up in 5cm lead to protect it from alpha, beta and most gamma radiation.