Communications: Greater message capacity for satellites: Techniques such as the use of new frequencies, digital encoding, and bandwidth compression will increase mission efficiency

The satellite communication techniques that have allowed dramatic growth in services in the last 15 years are nearing their useful limits. These techniques have relied on increases in both power and bandwidth as each new satellite has been placed in orbit. Some satellites in a geostationary arc are now only about 3° apart, and some arcs are already crowded. Newly allocated frequency bands need more advanced technological developments to be useful. Because power is related to mass, powerful satellites for geostationary orbit are limited by expendable launch-vehicle capacity of about 1300 kilograms per satellite.