Tiny flying insect robot has four wings and weighs under a gram

A solar-powered flying robot has become the lightest machine capable of flying without an attached power source. Weighing just 259 milligrams, the insect-inspired RoboBee X-Wing has four wings that flap at a rate of 170 times per second. It has a wingspan of 3.5 centimetres and is 6.5 cemtimetres high. The flying robot was developed by Noah Jafferis and colleagues at Harvard University. Its wings are controlled by two muscle-like plates that contract when voltage passes through them.