MEMS electrostatic sail. Coloured scanning electron micrograph of a close-up of an electrostatic sail, or radial motion actuator, MEMS (microelectromechanical systems) device. MEMS devices are constructed on a microscopic scale using technologies such as wet and dry etching and thin film deposition. Applications include sensors and optical displays. Materials used to construct MEMS devices include silicon and polymers such as plastics. This prototype, utilises a negative poisson structure in the centre. Magnification: x787, when printed 10 centimetres wide.