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 July It weighs about kilogrammes is centimetres cm long and cm 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