● GRAIL · GRAVITY RECOVERY & INTERIOR LABORATORY
NASA DISCOVERY PROGRAM · 2011–2012
Weighing the Moon · NASA GRAIL

The Moon, measured

Two spacecraft. One micrometer of difference. The most detailed gravity map of another world ever made, on a globe you can spin.
GRAIL gravity map of the Moon
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Mass excess Basin Gravity low Crater Landmark
Gravity map (GRGM1200A): NASA / JPL-Caltech / MIT / GSFC · surface texture Solar System Scope (CC BY 4.0)
MoonKAM image of the lunar far side with Earth beyond
Interactive · Mission Ops

MoonKAM: let the kids fly it

Every GRAIL spacecraft carried a camera aimed by middle-schoolers. Recreate a real image request and watch a genuine frame downlink from lunar orbit.

Enter Mission Ops
Artist rendering of the twin GRAIL spacecraft
The story

The full mission

Launch, twin-spacecraft ranging, discoveries, and a deliberate crash named for Sally Ride. The story and the numbers.

Read the mission