Communication satellites, sometimes abbreviated as comsats, are small, automated satellites placed in orbit around UEG worlds to relay communications signals. They are also known as communication buoys. They are found in orbit above several major worlds, including Earth, Sigma Octanus IV and formerly Reach. They can be accessed through the planetary network, and AIs such as Cortana and Serina have done so for various purposes.

Communications satellites may use slipspace to send transmissions across UEG space, as it is known Earth civilians can have Waypoint conversations with people as far as the Outer Colonies through them, rather than simple video messages.