Spacetrooper armour is a ship (technically according to the rules pages), so anyone that isn't restricted by their race can use it. However its GE tech and unlikely that many people will see one let alone be able to use it.
And stromtrooper NPCs are again GE only.
EDIT to your edit: You'd need to get one from the GE, but that will be as likely to succeed as to be given an SSD.
Edited By: Ellias Aubec on Year 10 Day 224 7:50 ____________