Calibration teams at the USGS EROS Center use a variety of methods to make sure the data collected by Landsat satellites are an accurate representation of the Earth’s surface. They’re constantly comparing new imagery to old, tweaking algorithms to correct issues that might emerge, and using unchanging Earth surface sites and on-the-ground readings to check for consistency. Since the launch of Landsat 8, they’ve come to rely on another unchanging landscape to check for quality: the lunar surface. In this episode of Eyes on Earth, we hear how it’s done.