THE Lunar Rover, a vehicle resembling a stripped-down dune buggy, allowed the astronauts of the last three Apollo missions to traverse the Moon's desert-like surface. A full-size working replica of the Lunar Rover will be displayed at the 'Our Time in Space' exhibition to be held at the Hong Kong Science Museum next month. Two silver-zinc batteries powered the electric motors on each of the four wire-mesh wheels, giving the Rover a top speed of 14 kilometres an hour. The Lunar Rover was carried to the Moon in the cargo compartment of the descent stage of the Lunar Excursion Module (LEM). To make it more compact, the Rover's frame was hinged with three segments folded together. The wheels folded against the chassis. The vehicle, which carried scientific instruments to be used on the Moon, with a compartment for storing Moon samples to be returned to Earth, enabled the astronauts to move farther afield.