Space Situational Awareness Satellites
Space situational awareness (SSA) is the detection and tracking of objects in space to ensure they do not pose a collision threat to other objects, such as operational spacecraft. Objects are detected using a combination of ground-based optical telescopes and radar. The optical telescopes have finer resolution than radar and can detect smaller objects further away, but they work only at night. Radar can operate at night or during the day, but with a lower resolution than optical sensors. However, unlike optical sensors, radar systems can automatically scan the sky and identify and track targets.
A series of SSN upgrades are underway. In 2011, a DARPA-funded space surveillance telescope underwent testing. After nine years of development, the new telescope, located at White Sands Missile Range, New Mexico, is capable of capturing wide-field views of objects in GEO orbit. While the SSN uses radar signals to track objects in LEO, distant objects in GEO orbits are tracked by optical systems such as the DARPA telescope at White Sands and other telescopes in Hawaii; Socorro, New Mexico; and the island of Diego Garcia in the Indian Ocean.
In 2010, the United States launched the first Space Based Space Surveillance satellite (SBSS-1) for its Space Surveillance Network. From its LEO orbit, SBSS-1 supplements ground-based equipment that tracks more than ## objects ## centimeters (## inches) or larger orbiting Earth. Its vantage point in space means that its observations of other objects in space are not affected by weather, lighting, or distortion that can be caused by the Earth’s atmosphere. This enables more accurate and timely information regarding objects’ orbital paths, thus allowing for earlier warnings of potential spacecraft collisions.
Another notable launch in 2010 was the first Space Based Space Surveillance satellite (SBSS-1) for the U.S. Space Surveillance Network. This branch of U.S. Strategic Command is tasked with detecting, identifying, and tracking space objects in order to provide true situational awareness in space. From its LEO orbit, SBSS-1 will supplement ground-based equipment that tracks more than ## objects orbiting Earth. Its vantage point from space means that its measurements are not subject to weather, lighting, or distortion that can be caused by the Earth’s atmosphere.
One specialized type of system that uses both satellites and ground stations is dedicated to space situational awareness (SSA). An SSA system tracks satellites and other objects orbiting Earth. This is accomplished through a series of ground stations which are dedicated to scanning the sky via a variety of means in order to detect and plot the courses of objects in space. This data is then compiled and analyzed to create a series of predictions regarding possible collisions.