Trafalgar is buying Scrap for 4437 per unit. One can just mine it outside the station and sell it right away with zero risk involved. It takes about 5-6 min to fill a Salvager and sells for ~14.5 millions.
Same applies to Southampton, and 2-3 other stations are fairly close too.
Nomad fighter NPCs (Voidrunner) are shieldless and are sometimes immune to damage.
Edit: A friend told me the latter is probably because of a certain texture pack I installed.
