Introduction
Launched into the night sky nearly 26 years ago, on December 19, 1999, from Vandenberg Air Force Base (now Space Force Base), Terra was NASA’s first Earth Observing System (EOS) Flagship mission to study Earth’s land surface from space via a coordinated series of polar-orbiting and low-inclination satellites that produce long-term global observations useful for understanding the interactions between Earth’s atmosphere, land, snow and ice, oceans, and radiant energy balance. Scheduled for a six-year tour, Terra outlasted its life expectancy by nearly two decades. Despite its longevity, Terra’s mission scientists stopped making inclination adjustments in 2020, allowing the satellite to slowly drift out of its contained orbit. The mission team has also begun the painful process of shutting down the five key instruments as the satellite is prepped for retirement.
“Terra’s impressive human legacy stems from the fact that the mission’s history is grounded in NASA icons,” said Nyssa Rayne [NASA Goddard Space Flight Center (GSFC)—Terra Outreach & Communications Coordinator]. “Even today, Terra continues to benefit from legendary figures, including the current project scientist and instrument calibration/validation experts, who have shaped this mission in monumental ways.”
An Auspicious Beginning to More Than Two Decades of Science
Terra’s mission of discovery was designed to provide a better understanding of the total Earth system. Up to this point, the research community k …