Space situational awareness (SSA) is the ability to accurately characterize the space environment and activities in space.
Civil SSA combines positional information on the trajectory of objects in orbit (mainly using optical telescopes and radars) with information on space weather. Military and national security SSA applications also include characterizing objects in space, their capabilities and limitations, and potential threats.
Ground-based radars have historically been the backbone of SSA. The primary advantages of radars are that they can actively measure the distance to a target and some types of radars can accurately track many objects at once. Some radars can also detect the motion of an object and construct a representation of its shape. The main disadvantages of radars are their cost, size, and complexity.
Optical telescopes are also widely used for SSA. The main advantages of using optical telescopes for SSA is their ability to cover large areas quickly and, in particular, to track objects above 5,000 km altitude. Some telescopes can create high resolution images of space objects. The main disadvantage of optical telescopes is that they require specific lighting conditions and clear skies to see an object, although space-based optical telescopes eliminate some of these limitations.
Other types of sensors can be used for SSA, including sensors that detect radio frequency (RF) or other types of signals from satellites, lasers that measure the distance or range to a satellite very accurately, and infrared sensors that detect heat. Combining data from many different types of sensors, both ground- and space-based, that are also distributed around the globe provides a much more complete picture of the space environment and of activities in space.
Although historically done by the U.S. and Russian militaries, today there are a growing number of countries, academic and scientific institutions, commercial companies, satellite operators, and even private citizens who are providing various types of SSA data.
Over the last few years, there has been increased activity from the private sector on SSA. Multiple companies are now developing or providing data and analysis services to governments and satellites operators.
Examples of companies that offer SSA services include:
- LEO Labs
- Lockheed Martin Corporation
- L3Harris Technologies Inc.
- ExoAnalytic Solutions
- NorthStar Earth & Space Inc.
- GlobVision Inc.
SSA is critical to the long-term sustainability of outer space. It provides knowledge that allows everyone who uses space to evaluate the impact of their activities and make informed decisions. SSA makes using space safer and more efficient and enables protection of valuable satellites and space-based services.
SSA also provides a level of transparency to reduce tensions, help verify agreements between countries, and prevent accidents or misperceptions from triggering or escalating conflict.
Source: Secure World Foundation