The Mars Climate Orbiter was designed to facilitate communications between Earth and Mars. However, due to a mismatch between the units used by different NASA teams, thrust calculations were incorrect, causing the spacecraft to burn up in Mars' atmosphere. Two subsequent Mars rovers, Opportunity and Spirit, were successfully landed in 2004 and found evidence of ancient saltwater lakes on Mars, continuing scientific study of the planet's climate for over 5 years. While expensive missions can fail, the knowledge gained from failures can enable future successes.