In April 2026, NASA’s Artemis program took humanity back to the Moon, providing a new look at Earth’s only natural satellite. As the world celebrates the return of Artemis II’s four astronauts, the lunar surface continues to play a critical role in missions much closer to Earth.
Since 1972, the NASA/USGS Landsat program has captured the longest continuous record of Earth’s land surface, collecting images that track everything from crop health to glacial change. But with such a long data record, how can scientists trust that images acquired today can be accurately compared to those from days, years, or even decades ago? They look to the Moon.
Unlike Earth, with its constantly changing weather, seasons, and landscape, the Moon is remarkably stable. With no atmosphere and virtually no surface changes, the Moon reflects sunlight in a predictable, consistent way. This stability gives engineers a reference to fine-tune Landsat’s instruments and be confident that the data are accurate.
Once a month, during the full Moon, the spacecraft turns its instruments away from Earth and points them directly at the lunar surface. Over the course of two orbits, the spacecraft maneuvers to image the moon 15 times. During each pass, Landsat captures detailed measurements of light reflected off the Moon’s surface, revealing any unintended sensor change, or “drift,” that needs correction.
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