Each DSN complex contains one 26-meter (85-feet) diameter antenna that is used primarily to track Earth-orbiting spacecraft which orbit between 100 and 620 miles (160 and 1,000 kilometers) above the planet.

A special mount (an X-Y mount) allows these antennas to point low on the horizon to pick up the fast-moving Earth orbiters as soon as they rise into view. The maximum tracking speed is three degrees per second, which is the equivalent of tracking one full rotation of an Earth-orbiting spacecraft every two minutes.

The 26-meter antennas were originally built to support the Apollo missions, which sent human explorers to the moon between 1967 and 1972.