SPACE SURVEILLANCE NETWORK

The United States Space Surveillance Network (SSN) has been tracking space objects since 1957 when the Soviets opened the space age with the launch of Sputnik I. Since then, the SSN has tracked more than 26,000 space objects orbiting Earth. The SSN currently tracks more than 8,000 man-made orbiting objects. The rest have re-entered Earth's turbulent atmosphere and disintegrated, or survived re-entry and impacted the Earth.

The space objects now orbiting Earth range from satellites weighing several tons to pieces of spent rocket bodies weighing only 10 pounds. About seven percent of the space objects are operational satellites (i.e. ~560 satellites), the rest are space debris. USSTRATCOM is primarily interested in the active satellites, but also tracks space debris which upon reentry might otherwise be mistaken for incoming missiles. The SSN tracks space objects that are 10 centimeters in diameter (baseball size) or larger.

Non-Military Satellite Services

There are three basic categories of non-military satellite services:

Fixed Satellite Service

Fixed satellite services handle hundreds of billions of voice, data, and video transmission tasks across all countries and continents between certain points on the earth’s surface.

Mobile Satellite Systems

Mobile satellite systems help connect remote regions, vehicles, ships, people and aircraft to other parts of the world and/or other mobile or stationary communications units, in addition to serving as navigation systems.

Scientific Research Satellite (commercial and noncommercial)

Scientific research satellites provide us with meteorological information, land survey data (e.g., remote sensing), and other different scientific research applications such as earth science, marine science, and atmospheric research.

Air Force Space Surveillance System

The Air Force Space Surveillance System (AFSSS), also known as the "space fence", is a very high frequency radar network located at sites across the southern United States (from California to Georgia) with a centralized data processing site at the Naval Network and Space Operations Command in Dahlgren, Virginia. The "fence" is now operated by the U.S. Air Force (20th Space Control Squadron Detachment 1).

The Satellite Detection and Reconnaissance Defense (the former designation of the NSSS) reached initial operating capability in 1961. Since then, the role of the "fence" has grown. The system detects space objects from new launches, maneuvers of existing objects, breakups of existing objects, and provides data to users from its catalog of space objects. Orbital parameters of more than 10,000 objects are maintained in this catalog -- which has now gained usage by NASA, weather agencies, and friendly foreign agencies. The information is essential to computing the collision avoidance information to de-conflict launch windows with known orbiting space objects.