Hmmm.... I'm wondering if this could be made into a two-stager... Put a 3-motor inline cluster in the booster, with a booster engine in the middle, and two short-delay engines in the outboards, and then have it gap-stage to a mini engine in the sustainer, with separation just below the ring tube. The transition would have a pass-through tube, connected to the stuffer in the booster with a coupler. Placed in alongside the stuffer tube would be one or two small parachutes for booster recovery. The ejection charges from the booster's outboards would blow off the transition and release the chutes (after the sustainer has left, of course). The pass-through tube in the transition would separate from the booster's stuffer tube at the aforementioned coupler. The sustainer would recover with a streamer. Hmmm...

But would all that additional mass mess up the stability margin? I am just thinking out loud as I type, here - I haven't simmed any of this.

Nice design in any event. But considering where it comes from, I would expect no less!

MarkII

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SAM # 0011