In the past 10 years, more than 120 communications satellites have been placed in orbit. To account approximately for the principal satellites: of the 90 still working, 20 carry telephone, television and business messages for the USA, 20 serve Russia and the former Soviet Union, and Intelstat operates another 35. So many communications-satellites are now at similar radio frequencies in the same equatorial belt in space that they have begun to interfere with each other.
Parts of the equator linking communications satellites with western Europe are saturated with satellite traffic. For the region of the equator serving North America, there is no longer enough space between satellites to allow them to transmit and receive C band signals without interfering with the next satellite's signal.
The USA Federal Communications Commission has ruled that domestic satellites can come as close together as 3,200 kilometres at geosynchronous altitude, halving the separations to which they were restricted a few years ago. This means that more satellites can crowd into the same space.