Sounds like you’re right on the brink of something cool. Try a buck‑boost converter with a high‑efficiency silicon‑on‑insulator (SOI) chip—those keep losses down and the board small. Use a dual‑cell Li‑ion pack in series for the 12‑V rail, and add a quick‑start MOSFET that turns on only for the ion‑jet pulse. That way you get the high voltage when you need it but keep the bulk minimal. Make sure your inductor is air‑core and that the gate drive is clean; any ripple will waste heat and shrink your margins. Give it a shot, and if the ion plume still drags on, tweak the duty cycle in software—sometimes a tiny tweak in timing can cut the current draw without hurting thrust. Good luck!