Abstract: The Earth Observing System (EOS) missions, Terra, Aqua, and Aura, are NASA’s flagship Earth Science missions and are part of the International Earth Science Constellation (ESC). The ESC is composed of satellites that fly in the Afternoon Constellation (also known as the A-Train) and the Morning Constellation. All missions fly in 705-kilometer altitude, polar sun-synchronous orbits that are inclined 98.2 degrees. NASA’s key operational priorities are to keep the satellites safe and maintain op…