Innovative vertical take-off aircraft with hot steam

HeiDAS UH (which stands for "HeißDampfAeroStat UltraHeiß" in German; = "hot-steam aerostat ultra-hot") is the world's first functional balloon that is powered by superheated water steam. The balloon was developed as joint project between Festo and the Department of Air and Space Travel at the Technical University of Berlin and is one of the most exciting and most comprehensive new developments in lighter-than-air aviation.


The HeiDAS UH is almost as efficient as helium balloons, but uses a very inexpensive, non-flammable buoyant gas – steam. The large quantities of water steam used for filling a hot-steam aerostat are produced with an innovative method of steam production borrowed from space travel.


Not only is the use of steam a technical revolution, but the development of suitable materials for the covering material and the insulation is especially innovative. The HeiDAS polymer film is a high-performance polyamide with a special remainder group that survived even brief temperatures of 310 °C in testing.


After the successful flight of the HeiDAS UH test vehicle it became clear that the lighter-than-air steam technology could open up completely new perspectives for aviation, particularly because of the drastically reduced costs of buoyant gas.