Landfill Beyond The Stars: No, just no.  It’s hard to imagine the economics that would make it possible to haul junk across space for dumping.  And that would make it worthwhile to waste an entire planet to store the stuff.  But…

…there are a couple of locations that specialize in recycling of exotic materials in, ah, ways that you wouldn’t want to live next door to, or even on the same planet as, or disposal of really awkward components that can’t just be dumped – like, say, singularities – and which occasionally store piles of things waiting to be recycled.  So, “junkyard beyond the stars”, that we can do you.