Space Situational Awareness Satellites
U.S.-based companies like Analytical Graphics, Inc. (AGI) are developing their own SSA initiatives. Supplying services based more on the USSTRATCOM vision of SSA to space operators, commercial SSA services, processes and teams offer an alternative to JSpOC. Although the notifications from the JSpOC are helpful, they still require a capable orbital analyst to analyze the data contained within the messages and calculate whether a particular satellite needs to move to avoid a collision. Hiring a full-time orbital analyst to focus only on collision avoidance can be expensive for smaller satellite operators, such as Planet Labs.
Since July 2010, the United States Strategic Command’s Joint Space Operations Center (JSpOC) has collected satellite orbit data and provided SSA to military, government, and commercial satellite operators through sending out predictions of close approaches for operational satellites. In October 2015, the U.S. Department of Defense (DoD) stated the intent to spend $6 billion on SSA activities and technology upgrades in the next five years.
Space situational awareness (SSA) is an important national security mission with strong dual-use applications. SSA systems are dedicated to tracking and characterizing every object in Earth’s orbit, making sure objects do not come close enough to each other to pose a risk of collision. They do this by scanning the sky with optical and radar-based sensors, tracking the positions and courses of orbital objects, and predicting their future positions. Most SSA information is collected from ground-based systems—there are only a few satellites that contribute data to this function.
Europe is investing in a pan-European SSA capability through an ESA program that was initiated in 2009. Investment of €## million (US$## million) was initially requested for full-scale development, but ESA governments decided to spend only €## million (US$## million) over three years. So far, ESA has spent €## million (US$## million) on development. Some of that funding supported construction of ## prototype space surveillance radars. The first radar, located in Spain and built by Germany, was completed in October 2012 with validation and testing beginning in November.
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.
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.