Super Moon Helps NASA's Landsat 8 Satellite with its Steady Light (VIDEO)

NASA's Landsat 8 doesn't just look down at Earth; it also looks to the moon. Now, after this past weekend's full moon, Landsat 8 has used the moon's light to perform some crucial tests.

Landsat 8 pivots toward the moon every month as it turns full. It then scans the distant lunar surface multiple times before flipping back to continue collecting land-cover data of the sunny side of Earth below. Landsat conducts these monthly lunar scans in order to ensure its land-imaging instrument is detecting light consistently. Since the moon is a consistent source of light, it provides the perfect ruler by which to measure Landsat's instrument.

"We really wanted something we could trust for Landsat 8," said Brian Markham, leader of the calibration team for Landsat 8, in a news release. "We do have Earth sites we look at for calibration. But the precision with which you can track things by using the Earth, because of the atmosphere, is not as good as the moon."

If during these lunar tests Landsat's 8 Operational Land Imager (OLI) detectors indicate that the moon is getting slightly duller or brighter, then scientists know there's something wrong with the instrument. With this test, the researchers can adjust the instrument and recalibrate it.

"Everything else we've tried to use to monitor the stability of our instruments has often not been as good as the instruments themselves," said Markham. The moon, however, is a steady source of light. "As long as we know what its illumination conditions are, we can trend our instrument performance to it because we trust its stability."

Currently, the lunar calibration tests show that Landsat's detectors are stable, within a fraction of a percent. Next time you see a full moon, don't just admire the way it looks; also remember that it's a useful tool for scientists working with satellites.

Want to learn more? Check out the video below, courtesy of NASA.