Wind tunnel test. The 'Mirador' miniature UAV (unmanned aerial vehicle) undergoing wind tunnel tests. A laser is directed over the surface of the UAV as part of a test known as laser doppler velocimetry (LDV). LDV allows researchers to record minute changes in aerodynamic properties. Mirador was designed by the French defence research agency ONERA and the Belgium Royal Military Academy of Brussels. It is a fixed-wing propeller-driven aircraft powered by a fuel cell. It measures 25 centimetres long and can fly for 20 minutes. It is able to carry small cameras and other sensors for military or civilian surveillance. Photographed in 2005.