Sojourner. View of a model of the Mars Pathfinder robotic rover vehicle Sojourner, moving over a surface that mimics Mars. The true rover vehicle landed on Mars on 4 July 1997. It weighs about 9 kilogrammes, is 63 centimetres (cm) long and 48cm wide. Its wheels and suspension are designed for movement over Mars rocky surface. It is powered by a solar panel (at top) which allows for a few hours of movement per day, and is controlled by an operator on Earth. The Sojourner is equipped with an Alpha Proton XRay Spectrometer (APXS). The APXS determines the chemical composition of martian rocks.
