TL;DR: this is a map of the world. You put in the date and trajectory, and it charts where the shuttle is as it orbits the Earth, in real time. This map include

TL;DR: this is a map of the world. You put in the date and trajectory, and it charts where the shuttle is as it orbits the Earth, in real time. This map includes world-wide transmission stations, which basically follow the shuttle's orbit around the globe. It was run on these laptops on the shuttle for years: https://en.wikipedia.org/wiki/Grid_Compass https://en.wikipedia.org/wiki/Grid_Compass