Satellites in a low-earth orbit circle the planet about once every 90 minutes, and are visible from a point on the ground for less than 10 minutes of their 90-minute pass. At any given time in a pass, relative to a known ground position, the location of the satellite can be reduced to altitude (angle above horizon), azimuth (position along horizon, relative to north), and distance. When a satellite is high enough above the horizon, a clear communication path can be established. We predict these passes, then orient the antenna to point at the satellite. The communications module can then communicate with the satellite; meanwhile, the tracking software must continuously readjust the position of the rotator, since the satellite passes across the sky in just minutes