Satellite Communications

DARPA looks to upgrade space junk monitoring

The Defense Advanced Research Projects Agency is willing to spend as much as $1.4 million on a program to track low-inclination, low-Earth orbit objects, the agency announced in an update to a posting on the FedBizOps website.

The original posting in December solicited white papers for a research directive titled, “Uncued Detection of Low Inclined Low Earth Orbit Objects (LILO).” A low inclination means that an object is orbiting at a low angular distance from the plane of reference, which is defined as the Earth’s equator. The project is looking at objects orbiting within 20 degrees north and south of the equator. Current uncued radar detection of LEO objects is limited by geographic location.

The project aims to improve DARPA’s OrbitOutlook (O2) program, which is designed to augment the U.S. Space Surveillance Network (SSN) with additional data from diverse sources. SSN is a worldwide network consisting of both ground and space-based sensors that observe and catalogue space objects.

However, according to SpaceNews, DARPA was noncommittal when asked if the information from the project would be used by the Air Force’s Joint Space Operations Center, which is responsible for analyzing information from the SSN.

DARPA has required that the system:

  • Provide uncued detections of space objects up to an altitude of 1,000 and orbital inclinations of 0±20 degrees or 180 ± 20 degrees at the time of detection.
  • Detect objects that are 10 centimeters in size and above.
  • Provide astrometric accuracy of less than six arcseconds.
  • Provide timing accuracy of less than 10 milliseconds.
  • Provide more than three independent detections per object within a single 10 minute window.


In a question and answer session posted on Feb. 11, DARPA said the price tag of the project could be up to $1.4 million. In the second phase of the effort, DARPA is looking to use a data-buy scenario with the performer maintaining ownership, operation, and maintenance of the sensors. The data is to be transmitted to a centralized DARPA database for final data validation algorithms.


Space debris has been a growing concern for the military as they increasingly rely on satellites for navigation, surveillance, and communication. According to NASA, about 500,000 pieces of space junk are being tracked as they orbit Earth. Traveling at 17,500 mph, even the smallest pieces of debris can damage or destroy important satellites.


Earlier this year, the Air Force’s Boeing Space-Based Space Surveillance system, an all-weather, low-Earth orbit sensor, was reported to have decreased risk to satellites by 66 percent through early, space-based detection.

About the Author

Joey Cheng is an editorial fellow with Defense Systems.

Defense Systems Update

Sign up for our newsletter.

Terms and Privacy Policy consent

I agree to this site's Privacy Policy.