Ultra High Frequency Follow-On (UFO) satellite system is a United States Department of Defense (DoD) program sponsored and operated by the United States Space Force to provide communications for airborne, ship, submarine and ground forces.

The ground terminal segment consists of equipment and resident personnel at existing satellite communication stations.

The Ultra high frequency (UHF) satellites primarily served tactical users.

Satellites eight, nine and ten also carry the Global Broadcast Service antennas that operate in the Ka-band.

Block 2 satellites, starting with UHF 4, added extremely high frequency package with 11 channels.