Before revision: A rockoon (from rocket and balloon) is a solid fuel sounding rocket that, rather than being lit immediately while still on the ground, is first carried into the upper atmosphere by a gas-filled balloon, then separated from the balloon and ignited.
After revision: A rockoon (from rocket and balloon) is a sounding rocket that, rather than being lit immediately while still on the ground, is first carried into the upper atmosphere by a gas-filled balloon, then separated from the balloon and ignited.