[dandelany]

I have thought about this too, retrograde orbit buys you a lot of “free” energy for deorbiting things going in the other direction. The “puff coherency” problem as you succinctly put it seems like the hardest problem. Maybe if the gas is ionized, you could use another spacecraft[s] to generate a magnetic field that could trap the cloud long enough to get the “puffer” craft out of the way before impact.