DOD satellites are controlled in orbit by the Air Force
Satellite Control Network (AFSCN), which tracks the satellites, receives and
processes telemetry transmitted by them, and sends commands to them. Dedicated
control segments support individual satellite systems, but a common user element
provides support to all DOD satellites. The common user element consists of two
control nodes, two scheduling facilities (one at each node), nine remote
tracking sites, and communication links connecting them.
The common user element of the AFSCN was originally activated to support the
Discoverer program of the late 1950's and early 1960's. An interim satellite
control center was initially established in Palo Alto, California, in January
1959, but by June 1960, a permanent control center had been established in
Sunnyvale, California. The installation in Sunnyvale was originally referred to
as the Satellite Test Annex, then as Sunnyvale AFS, then as Onizuka AFS, and
finally as Onizuka AFB. The control center at Sunnyvale was complemented by
tracking stations established at nine different locations between 1959 and 1961.
In later years, some of those tracking stations were taken out of service and
others were added, and a second control center was added--the Consolidated Space
Operations Center (CSOC), located in Falcon AFB, Colorado.
The Secretary of Defense authorized development of the CSOC in 1979.
Originally, it was to consist of two parts--a Satellite Operations Complex
(SOC), which would be used for on-orbit control of DOD satellites, and a Shuttle
Operations and Planning Center (SOPC), which would be used for the planning and
control of DOD missions on the Space Shuttle. However, the SOPC was canceled in
1987, leaving the CSOC with one mission--that of satellite control. The CSOC
came on line gradually, starting in 1989. It successfully completed Initial
Operational Test and Evaluation in August 1993 and was turned over to Air Force
Space Command the following month.
The hardware and software used in the AFSCN has undergone numerous upgrades
in the last three decades. One of the most significant upgrades was the Data
Systems Modernization program, which introduced new computer hardware and
software to perform command and control of orbiting satellites. The program was
initiated in 1980, and by February 1992, the new hardware and software was able
to perform all functions needed to support the satellites then in orbit. The new
system was more reliable than the old one, cheaper to maintain, and faster in
its operation, allowing it to support a steadily increasing satellite support
workload.
Another significant upgrade was the Automated Remote Tracking Station (ARTS)
program, which introduced new, modern equipment at the tracking stations. The
contract for Phase I of the ARTS program was awarded in 1984 and the contract
for Phase II in 1988. The Phase II contract expired in March 1995, and by that
time, ARTS equipment had been installed at all the existing tracking stations
and had been used to establish new tracking stations at Colorado Springs and on
the island of Diego Garcia. The new equipment offered improved reliability,
increased the operational capacity of the tracking stations, and automated many
of the functions they performed. Automation and improved reliability reduced the
manpower required to operate and maintain the tracking stations and reduced
operation and maintenance costs.
Headquarters of
the Air Force Satellite Control Facility at Sunnyvale AFS, California, in the
early to mid-1980s. At the time, this was the only satellite control center
operated by the Air Force.
The Consolidated
Space Operations Center (CSOC) at Falcon AFB, Colorado. The CSOC was the second
satellite control center activated by the Air Force. It was turned over to Space
Command in September 1993.
The tracking
station at Kaena Point on the island of Oahu, Hawaii.