“In the game I was in”
Well, in several games I was in, we had profitable salvage operations, including running a *published adventure* about salvage. I think it was even adventure #1. That proves it! :-)
Anyways, It would be super expensive now, but in the future, it’s a simple, cheap operation:
1) Find some junk
2) Fly to said junk
3) Attach a beacon and small thruster, reactor and computer to said junk
4) watch it preform a slow holman transfer orbit to a processing facility. (30 days of even .1 gees of thrust is a LOT of delta-v)
5) profit
It actually seems like it would be more profitable then asteroid mining. As there is no digging or blasting. Just pure high value materials. I have a feeling that the asteroid miners sweep the system on their way in and out and see if they can find any quick and dirty claims.
And PIRATES! yep, this totally allows for pirates. Jump in, steal junk that’s hoofing it in system, and jump out. Well, dirt poor pirates. Who steal garbage. Adam Quark would be scared!
Also - if you have a ship sized hunk of superdense just hanging out in the system, probably with a lanthanum grid segment in it, you’d think people would be all over it. If it’s much smaller then a ship and has a low delta-v, then the early warning systems would categorize it as “junk” and promptly relegate it as a navigation hazard. Not that a small hunk of junk is going to jump in system, and disgorge fiery death and marines on the system. So we can safely ignore it for this discussion.
All of that being said, I really don’t see how a moderate population, moderate tech planet is going to not have the time to warm up their deep meson sites and scramble their fighters before a fleet is able to get in system, barring black globes etc.
And I like it that way. Fleets popping out of hyperspace above my capital make for poor storytelling.