clearing bits far away from computation

[Bob Jenkins]

I'm not sure what you mean by "swapping bits", but writing a bit requires joules per bit, and is an irreversible process.

Replacing (x,y) with (x, y XOR x) is reversible. It is its own reverse, because doing it twice yields (x, y XOR x XOR x) == (x, y).

So this is a reversible process: (x, y) -> (x, x XOR y) -> (x XOR x XOR y, x XOR y)==(y, x XOR y) -> (y, x XOR y XOR y)==(y, x). That's swapping bits. If you want zeros in the second bit, it's enough to be able to irreversibly clear the first bit.

An improvement in another part of this design: the energy and accuracy needed to toss rocks large distances. It can be aided by gravitational assists. And gravitational assists don't need accurate tosses up front, you can split the rock into two or three pieces in flight so that each piece gets a gravitational assist by different objects. If there is an equal mass of rocks going out as coming in, the accelerating assists in one direction are cancelled by the decelerating assists in the other, so the large objects doing the assist pretty much go along their orbit unhindered.

I'm still stuck on the mass distribution / stability of the central core. I'm getting closer to being able to simulate it, I have a high precision floating point library and interpolation working now.