For 20 years, Terra, the flagship Earth observing satellite, has chronicled changes on Earth. Designed and built in the 1980s and 90s, NASA and Lockheed Martin engineers set out to build a satellite that could take simultaneous measurements of Earth’s atmosphere, land, and water. Its mission – to understand how Earth is changing and to identify the consequences for life on Earth. Season after season, Terra data continues to help us understand how the evolving systems of our planet affect our lives – and how we can use that data to benefit society.