How NASA Uses the Full Moon to Calibrate Its Earth-Gazing Satellite
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How NASA Uses the Full Moon to Calibrate Its Earth-Gazing Satellite

The full moon-like yesterday's glorious event -is a great show for us here on Earth. But for NASA, it also plays a critical role in keeping its Landsat 8 satellite working properly. How? By using the moon exactly like a photographer uses a light meter.

Landsat 8 is all about Earth: It's designed to image our planet for use by the government and us citizens. But once in a full moon, this little satellite pulls its gaze from its main priority and turns in a different direction: The Moon. Because the full moon is so bright, it provides a chance for NASA's engineers to make sure Landsat is reading Earth's more patchy brightness levels clearly.

Because the Earth has no atmosphere and a surface that's uniform, it's the most stable place for NASA to check Landsat against. Here's how PhysOrg describes the process:

The timing is set for just after the moon is completely full. Then, as Landsat 8 passes over Antarctica and heads north in Earth's shadow, the spacecraft maneuvers to the precise location to start the first scan across the lunar surface .

It executes tiny and precise scans to take seven or eight passes across the moon - each one angled so that a different detector is centered on the moon. This takes about 18 minutes, by which time the spacecraft has almost reached the Arctic.

So the moon, which is such a constant here on Earth, is also playing a role in keeping our exoplanetary concerns stable. [ PhysOrg ]

Image: KPG_Payless .