Mars rover. Artist's impression of the Micro-rover vehicle Sojourner" on the surface of Mars. Sojourner will be carried to Mars by the Mars Pathfinder spacecraft, seen here in the background in late 1996. The rover weighs about 9kg, is 63cm long and 48cm wide. It is powered by a solar panel which will allow for a few hours movement per day, and is controlled by an operator on Earth. The main objective of Sojourner is to study rocks on the surface of Mars. To this end it carries an alpha-proton X-ray spectrometer (APXS) and a high-resolution camera. Sojourner will also provide extensive engineering data toward the design of future planetary rover vehicles."