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Satellite Broadcasting

1965  NHK announces it's own satellite broadcasting concept
1966 STRL begins studies on broadcast satellites
1972 NHK requests launch of experimental broadcast satellite (BS)
1973 Space Activities Commission approves a BS development plan
1978 Launch of BS
1984 Launch of BS-2a
1986 Launch of BS-2b
1989 Satellite broadcasts begin regular program services


On May 12, 1984, the world's first full-scale direct reception satellite broadcast (BS) service was launched in Japan. Coming approximately fifty years after the start of broadcasting, NHK's BS service overcame the difficulties of providing TV service to certain areas of Japan. Nearly twenty years had passed since then-President of NHK Yoshinori Maeda presented the satellite broadcasting project plan in 1965.

1984 World's First Direct Reception Satellite Broadcasting

Direct Reception Satellite Broadcasting Concept

If radio waves can be transmitted from a satellite in space, simultaneous communications, and broadcasts, over a wide area must be possible. A geostationary satellite has an orbital period that is the same as the earth's rotational period. Three geostationary satellites could have a range of transmission covering the entire planet with the exception of the North and South Pole areas. This idea was first advanced by the British science fiction writer Arthur C. Clarke in 1945.

Twenty years later, in 1965, then-President of NHK Yoshinori Maeda announced a plan to provide satellite broadcasting directly to individual homes. This was to make nationwide broadcasting in Japan a reality.

Research Begins on Broadcasting Satellite

In 1966, STRL began research on the various aspects of such a satellite system, including bus systems, control systems, transponders, and home receivers. A small, elliptical low earth orbit satellite was designed and manufactured as an A-type satellite (approx. 10kg) for one audio channel, and a B-type satellite (approx. 45kg) for one TV channel. Various tests were conducted in the new space environment laboratory.

While the satellites developed in 1968 were quite small in comparison to current broadcasting satellites, which can weigh over 500 kg, they provided valuable research experience.

Research Advances for Implementation

Japan initiated a full-scale national plan to develop a practical satellite by establishing the National Space Development Agency of Japan (NASDA) in 1969. At the World Administrative Radio Conference held in 1971, it was decided that the 12-GHz band would be used for satellite broadcasting.

The Space Activities Commission approved a plan to develop an experimental broadcasting satellite (BS) in 1973, building on the results of NHK's research on satellite transponders and antennas. Researchers from NHK were dispatched to the U.S. to provide the General Electric Company (GE) with engineering and manufacturing support for transponder development. Others went on loan to NASDA and aided in promotions for the project.

The BS was equipped with three 100-Watt TWTs, high-powered transponders for a satellite at that time, in order to provide dual-channel broadcasting. It employed three-axis stabilization system, instead of conventional spin-stabilization, for attitude control.

Satellite Broadcast Channel Plan

Radio waves transmitted from outer space can easily reach many different countries. In response to the increasing global interest in satellite broadcasting, the World Administrative Radio Conference (WARC-BS) in 1977 decided to assign broadcast satellite orbit locations and frequencies to each country.

NHK aided in the channel assignment plan at this meeting by way of a computer program that was developed by STRL. As a result, Japan was assigned eight channels, a larger allocation than that of some European countries.