Abstract: A thermodynamic kite comprising a non-rigid inflatable body member, a partially rigid helium storage envelope, and a rigid housing. The rigid housing being attached to the underside of the body member contains equipment for maintaining the kite at a preselected altitude as well as safety devices. Attached to the surface of the body member are an interconnected series of inflatable tubes which provide controlled rigidity to the inflatable body member. A radome containing a radar antenna is attached to the body member.