|
Did you know Harris built the U.S. portion of the communications link between the White House and the Kremlin for use during the Cold War?
Direct Communications Link Hotline
Released on May 3, 1974
The need for a DCL Hotline between Washington and Moscow first became clear during the October 1962 Cuban missile crisis. Consequently, a terrestrial USA-USSR hotline system was designed and put into operation in the fall of 1963, as was a backup radio link that was maintained by RCA Globecom. Both were duplex teleprinter circuits.
The prime communications link went from Washington, DC to London via trans-Atlantic cable, then on to Copenhagen, Stockholm, Helsinki, and finally Moscow. The radio backup circuit was relayed via Tangier, Morocco. Both paths were vulnerable and could have been interrupted or denied by an act of sabotage. Official concern in this country and the Soviet Union grew when the prime link was severed on several occasions. A Danish bulldozer operator once cut the line near Copenhagen. A Finnish farmer once plowed it up. A fire in a Baltimore manhole took it out of service temporarily.
Late in 1971, in order to guarantee a higher order of reliability and availability, it was decided to proceed with plans for a new hotline system using special ground stations in the USA and USSR, and orbiting communications satellites of the Molniya II and Intelsat IV systems.
In October 1972, the U.S. Army Satellite Communications Agency awarded a contract to the Radiation Division of Harris-Intertype Corporation to build the USA terminus — a complete Earth Station on a 15-acre site at Fort Detrick, Maryland. This USA Earth Station was the USA's part of a direct communications link via satellite between the respective heads of state in the White House and the Kremlin. Radiation's Direct Communications Link (DCL) Hotline program team turned the key of the new facility in the spring of '74. Top level Federal Government awareness of Radiation's achievement was evidenced by the many groups in attendance at briefings and tours of the site during construction. Radiation engineers operated and maintained the station and its equipment through 1977.
Facts From the Technical Brief
- The DCL Earth Station consisted of two identical communications systems that provided simultaneous transmission and reception of C-band, FM-modulated signals through 60-foot tracking and communication antennas.
- During the 8-hour period in which each satellite was mutually visible between Washington and Moscow, its pilot signal was autotracked by the two DCL antennas. Shortly before mutual visibility was lost, one antenna was commanded under computer control to the coordinates where the next satellite in sequence was to be acquired. Following automatic acquisition and the establishment of the communication circuit through the new spacecraft, the original circuit was broken and the second antenna moved over to provide backup.
- An interruption of communication for a period exceeding 5 milliseconds constituted a failure.
- The Mean Time Between Failures (MTBF) was greater than 835 hours.
- The mean time to restore one signal route to operation following a failure was not to exceed 15 minutes.
- Corrective maintenance took less than 45 minutes for 90 percent of all failures.
Learn More
A Timely Example of the Use of the DCL
The SALT II agreement met sharp opposition in the Senate. Critics argued that it would put the United States at a military disadvantage. Then in December 1979, the Soviets invaded the neighboring country of Afghanistan. When President Carter heard of the invasion, he activated the seldom-used White House-Kremlin hotline and protested to Brezhnev that the action was a "gross interference in the internal affairs of Afghanistan." As a result of the invasion, Carter refused to fight for the SALT II agreement and the treaty died.
|
White House
Kremlin
|
