Solar Systems with lots of asteriods but no planets

[Windborne]

How do you get around the inevitable destruction of your astroid and robo-mined planetary wealth? It seems like in a fairly short number of turns say 100 you'd have wore all your astroids out supporting your fleet?

Where are you storing the minerals you get each turn that aren't used for when your astroids start producing less and you have to find new places to mine?

I can sort of see how it would work for a short number of turns, 12 like you said is easy, but after a while I think your going to have some problems if you can't take a planet.

I know it would be very cool to have nomadic races with just spaceships and mining ships, research ships etc . . . but the game seems programmed specifically to make such races eventually die off.