History+of+U.S.+Military+Satellite+Communication+Systems

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-1946- the Army achieved radar contact with the moon -1954- the Navy began communications experiment using the moon as a reflect -1959- established an operational communitcation link between Hawaii and Washington D.C. -1960s- the department of defense (DOD) began developing satellite communication systems that would address the special requirements of military operations -Goals- provide communication between and to supply information to, military units in situations where means of communication are impossible, unreliable, or unavaible -Military Satellites Communications (milsatcom) architecture was developed for 3 populations of users :wideband, tactical, and protected -1st artifical com. satellite, Project SCORE (Signal Com. by Orbiting Relay Equipment) launched in 1958- to show that an Atlas missle could be put into orbit -2nd. Objective-demostrate a com. repeater built into the missle. -Aerospace participated in 1964 congressional hearings that resulted in a government policy to establish and maintain separate military satellite communication systems to satisfy unique and vital national-security needs that commercial systems could not satisfy -Lincoln Laboratory continued its investigation of space technology for application to military communications, developing the Lincoln Experimental Satellites (LES) series. -The first four LES satellites were launched in 1965 -demonstrated payload operations in space, supported propagation measurements, and helped improve ground equipment for both communications and satellite control -LES-5 was launched in 1967. Airborne, shipborne, and fixed and mobile ground terminals were involved in a large number of successful tests with LES-5, which operated until 1971. LES-6, used in similar tests, was launched in 1968. -These satellites clearly demonstrated that reliable communications could be extended to military units equipped with small terminals. the Initial Defense Communication Satellite Program (IDCSP) was created. Its design principle was simplicity. Each IDCSP payload had a single repeater with a capacity of about 10 voice circuits or 1 megabit per second of data when communicating with large terminals on Earth. -digital data were transmitted from Vietnam to Hawaii through one satellite and on to Washington, D.C., through another. In 1968, the system was declared operational, and its name was changed to Initial Defense Satellite Communication System. -The Tactical Communication Satellite (Tacsat), following the Lincoln satellites, was designed for a complementary function: operation with small land-mobile, airborne, or shipborne tactical terminals. -The Tacsat communication payload was designed with both UHF and X-band capabilities to permit operation- which was refined and subsequently applied to many commercial communication satellites. -Tacsat was used for operational support of Apollo recovery operations; it connected the aircraft, the aircraft carrier, and the ground stations. Military use, especially of the UHF band, was extensive -They demonstrated that satellite communications could satisfy certain DOD needs, so in 1968, DOD decided to proceed with the development of satellites for DSCS Phase II.