> but until we have a good story for fuel and waste processing then this is a nonstarter.
Waste processing in space? Just give it a slight push in the direction of the sun (or whatever the right direction is taking in consideration gravity) and forget about it.
That's not how orbital dynamics work; a slight push in any direction won't change the orbit enough for that thing to not be a problem anymore.
To make something fall into the sun, one needs quite a bit of delta-vee, which means energy. However, if the thing isn't in any hurry (and I imagine waste isn't), one can simply attach a solar sail with a tiny computer for steering it, and let it brake for the next few thousand years.
(Kerbal Space Program should be part of school curricula)
Pushing something into the sun requires removing most of it's orbital velocity not just a simple push. A small push in an orbit will create something on a very similar orbit to you that absent a nearby body to induce a lot of drag will intersect with your orbit in 2 places (not at the same time you're there fortunately in pretty much every case).
Waste processing in space? Just give it a slight push in the direction of the sun (or whatever the right direction is taking in consideration gravity) and forget about it.