Patent ID: 8286910

Claim:
Unmanned aircraft stationable at a pre-determined altitude in the stratosphere, comprising: a platform for telecommunications equipment or scientific equipment, an outer balloon having an aerodynamic external shape at least when present in the stratosphere, a pressurizable inner balloon fillable with gas, the outer and inner balloons supporting the platform, the inner balloon being arranged inside the outer balloon such that the outer balloon forms at least one insulating chamber around the inner balloon, circulation means for circulating gas through the at least one insulating chamber, at least one additional balloon arranged inside the inner balloon, the at least one additional balloon being attached on its underside to the inner balloon and configured such that an amount of gas in the at least one additional balloon is controllable to enable the inner balloon to be maintained at a constant pressure, connecting means for connecting an underside of the inner balloon to an underside of the outer balloon, and position maintaining means for maintaining the position of the platform with respect to the Earth.