thumb|A Deacon rockoon just after shipboard launch. thumb|A rockoon at liftoff, August 2022.
thumb|A Deacon rockoon just after shipboard launch. thumb|A rockoon at liftoff, August 2022.
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. This allows the rocket to achieve a higher altitude, as the rocket does not have to move under power through the lower and thicker layers of the atmosphere. A 2016 study by Acta Astronautica concluded that low-mass and high altitude launches give the best results.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).