June 19, 2022
Originally published July 27, 2012
image by Tom Harradine
A couple of nights ago I was taking a video of the Moon when two satellites passed close by, about 26 seconds apart. Calsky.com revealed them to be the satellites GRACE 1 and GRACE 2 (nicknamed "Tom" and "Jerry" ;). GRACE stands for Gravity Recovery And Climate Experiment. These two satellites trail each other 220km apart and measure the gravitational field of the Earth with particular focus on the polar ice caps and their changing mass over time. This is very much like the mission for the GRAIL spacecraft orbiting the Moon.
Yesterday's LPOD: Scrappy Scarp
Tomorrow's LPOD: Just Make It Sing