Commercialization of the Ground Segment

The creation of the Communications Satellite Corporation (COMSAT) and the subsequent launch of Early Bird in 1965 ushered in the era of true commercialization of this medium. It has largely gone unnoticed that one of COMSATs greatest legacies is its introduction of major earth stations for telephone and TV services to the general public. The very first transmissions over Early Bird used the same earth stations that were constructed for Telstar; however, these facilities had very limited service capability, both in terms of capacity and physical location. The intention of Early Bird and all of the INTELSAT satellites that followed was to improve the international telecommunications network. This demanded that earth stations be located in essentially every country of the world.

COMSAT worked in cooperation with AT&T, RCA, and others in the United States, and the major post, telegraph, and telephone (PTT) agencies of countries around the world, to standardize the design and operation of these large earth stations. They helped found the International Telecommunications Satellite Organization (INTELSAT), a treaty-based cooperative of national entities around the world. (INTELSAT was created as a quasigovernmental body but spun off its transponder-leasing business to a Netherlands-based satellite operator called NewSkies Satellites.)

A typical INTELSAT earth station of the 1960s, such as the COMSAT facility in Etam, West Virginia, represented a substantial investment yet offered connectivity with other earth stations through the GEO satellites operated by this consortium. While begun and nurtured by COMSAT, INTELSAT set out on its own in the mid-1970s and initiated a broad range of other services and applications of their space segment. The initial Standard A type of station (initially requiring 30-m antennas) was joined by more cost-effective Standard B earth stations (at 15m to 20m) that allowed countries to provide domestic satellite communication networks. Similar stations were installed as part of domestic satellite (DOMSAT) systems, such as the Palapa A network.

The INTELSAT system established its preeminence through the 1960s and early 1970s as the number of earth stations grew from hundreds to thousands.
Using technology and standards originally developed by COMSAT and improved along the way by INTELSAT and its members, the earth stations interoperate effectively. At all times, they maintain quality and order (no small task for a system used by a wide range of operating organizations on every continent).
Headquartered in Washington, D.C., INTELSAT manages the system using its control center, which is connected to TT&C and monitoring stations strategically located around the world. Individual earth stations, which are owned and operated either by members (e.g., the domestic telephone companies or PTTs) or other users who obtain their authority from these entities, are under the direction of INTELSAT’s control staff.
While INTELSAT saw its global system grow rapidly in terms of the number of satellites and earth stations, an important new phase of satellite communication appeared in 1971 when Canada launched its first GEO 
DOMSAT, Anik A (Anik means brother in the native Inuit language). Telesat Canada established the first domestic satellite system, which would become a model for more than twenty other countries. It pioneered applications like rural telephone service to remote regions and national TV broadcasting directly to major cities and small communities far from terrestrial transmitters. While INTELSAT required antennas of at least 15m in diameter, the performance of the Anik satellites allowed Telesat to employ 10m and even 4.5m antennas for these services (see Figure 1.6). This innovative system also spurred Canadian industry, allowing several companies to gain
a viable foothold as international suppliers of satellite and earth station equipment.

The United States, while a pioneer of commercial satellites and earth stations, took a back seat to Canada and only produced its first domestic network in 1974 with the launch of Western Union’s Westar 1 satellite. Being a purely commercial company, Western Union implemented its ground segment to augment its existing terrestrial microwave network. Westar earth stations were located in major cities around the country to support telephone, telex, and data communications. Later, the Public Broadcasting Service (PBS) became the first U.S. television network to use satellites for program  distribution and backhaul (e.g., the point-to-point transmission of video from temporary sites and remote studios at affiliated TV stations).

Integrated ground segments of the day, primarily used analog technology for telephone, telex, and television service, and depended on human operators to control access and manage services. The first domestic satellite system outside of North America was introduced in Indonesia and its neighboring Southeast Asian neighbors in 1976. The Palapa A satellites (named for a mythical fruit that Gajah Mada, an ancient king of Java, refused to eat until all of Indonesia was united) used the same design as Anik A. The ground segment was provided on an integrated basis by an international team consisting of the Indonesian PTT, Hughes Space & Communications Company, Ford Aerospace, ITT, and the TRT division of Philips. Internal to every earth station was a singlechannel per-carrier (SCPC) system that provided telephone service on a demand-assigned (DA) basis. This was directly integrated into the Indonesian direct-distance-dialed (DDD) automated telephone network that ITT
was installing at the time.

The timeline in Figure 1.2 indicates that 1975 was pivotal for mobile satellite communications, since this was the year Marisat 1 was launched.
This L-band GEO satellite was operated by COMSAT as a means to improve ship-to-shore communications, which at the time was still dependent on ionospheric reflection at high frequency. The first shipboard Marisat terminals still needed a dish type of antenna to provide adequate link performance for SCPC telephone and telex service. At the other end of the link is a land station acting as a gateway to the telephone network in the respective country. This service was so successful that COMSAT created Inmarsat, another alliance to promote the proliferation of earth stations in the global mobile ground segment. We will discuss again how Mobile Satellite Servicesgrew to extend to the air and land, providing communications to a wide varieter terminals.