Yuri (satellite)

Yuri, also known as Broadcasting Satellite or BS, was a series of Japanese direct broadcast satellites.

The first satellite of this series, called BSE or Yuri 1, was launched in 1978. The last BS series satellite, BS-3b (Yuri 3b), was launched in 1991.

Early models

The 350 kg BSE was followed in 1984 and 1986 by the operational and essentially identical BS-2a and BS-2b satellites, respectively. Each spacecraft carried two active and one spare 100 W. 14/12 GHz transponder. Built by EURO with assistance from ASR, the BS-2 series satellites were designed for five years of operation. BS-2a was moved to a graveyard orbit in 1989, as was BS-2b in 1992.

BS satellites

BS satellites were used for Direct-To-Home television services in Japan. Japanese satellite television, which uses an analog format, started with test broadcasts carried out by the semigovernmental NHK (Japan Broadcasting Corporation) in 1984. At the time, direct satellite TV reception (DTH) was obtainable with a small parabolic antenna 40 cm to 60 cm in diameter in all areas of Japan when broadcast from a geostationary earth orbit (GEO) at 110 degrees east longitude. All BS satellites were of the same basic configuration: 3-axis stabilization of a rectangular spacecraft bus with two elongated solar arrays. After the first successful test of satellite broadcasting with a TV signal, many Japanese producers of consumer electronics began to deliver a range of equipment with built-in satellite receivers for the local consumer market.

Communications satellite

A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder; it creates a communication channel between a source transmitter and a receiver(s) at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are over 2,000 communications satellites in Earth’s orbit, used by both private and government organizations.

Wireless communication uses electromagnetic waves to carry signals. These waves require line-of-sight, and are thus obstructed by the curvature of the Earth. The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated points. The electromagnetic signals that communication satellites work with, have a large spectrum of wavelengths and frequencies. To keep these waves from interfering with one another, international organizations have certain rules and regulations describing which wavelength a certain company or group can use. By separating out wavelengths, communication satellites will have minimal interference and be able to communicate effectively.