The Mars Exploration Rover Mission was extremely successful. The rovers surpassed the original 90 day plan by many years and replaced meters of distance driven on Mars with kilometers. The above graphic (Credit: NASA/JPL-Caltech) indicates the many achievements of Spirit and Opportunity. Below are some of the original expected rover capabilities as stated in Crisp, J.A. et al. (2003), Mars Exploration Rover mission, JGR-Planets, Vol. 108 (E12), doi:10.1029/2002JE002038: LEARN MORE