U.S. AIr Force Gen. William Shelton. Credit: U.S. Air Force/Staff Sgt. Christopher Boitz

Gen. William Shelton, commander of U.S. Air Force Space Command, sent SpaceNews a detailed, 1,100 word email Aug. 22 as a response to questions about the service’s space surveillance plans. 

Shelton explained his decision to close the current Space Fence, a line of very high frequency radars stretching across the southern United States, and described what a delay the contract award for the next-generation space-object tracking system means.

To make up for the lost capability of closing the old Space Fence, formally known as the Air Force Space Surveillance System (AFSSS), Space Command is looking at modified operating modes for the Perimeter Acquisition Radar Characterization System (PARCS) at Cavalier Air Force Station in North Dakota and the space surveillance radar at Eglin Air Force Base in Florida.  

Here are some highlights from the email:

“The need for space situational awareness has grown immensely over the past decade, driven in part by the increased reliance our Nation has on space capabilities, in part by the increase of space debris generated by the Chinese (anti-satellite) test and on-orbit collisions, and in part by the growing threats.  The AFSSS and other legacy sensors have been the backbone of our capability for years, but they were fielded in an era that had not seen the revolutionary changes in computing power and advanced electronics.  As the space domains become more congested, AFSPC has addressed these concerns by upgrading our command and control capabilities through the (Joint Space Operations Center) Mission System, and fielding more capable sensors, such as the Space Based Surveillance System and the new Space Fence.  The modernization of our sensors and our computing power provide a quantum leap forward in our ability to deliver quality space situational awareness for the Nation. 

“The AFSSS served our Nation well by providing critical understanding of the space environment since the early days of space exploration, through the Cold War, to today.  Transitioning to a more capable and sustainable network, the Eglin and (Perimeter Acquisition Radar Characterization System) PARCS radars will continue their role as critical space surveillance sensors mitigating the AFSSS by employing “fences” of energy that report on objects passing through them.  Eglin and PARCS enhance the report with more precise data measures that AFSSS cannot.  This higher-quality data quality will alleviate the decreased coverage volume from AFSSS.

“When we field the new Space Fence, it will bring to operations the best qualities of sensitivity, capacity and coverage.  The Space Fence will not only match the capacity of the AFSSS, but also improve the data quality of our network, providing unsurpassed space situational awareness for our warfighters and the Nation.”


“As part of the final Space Fence Engineering & Manufacturing Development Production & Deployment contract proposals, the Program Office has cost estimates for the first two years of operations and maintenance; however, until the contract is awarded these figures cannot be released due to sensitivities with source selection.  We are looking forward to the award and fielding of the Space Fence, which will provide enhanced capabilities and increased sensitivity, necessary to maintain situational awareness of threats.  As our reliance on space grows, our need to track and avoid these threats will also increase.”


“Neither the new operating modes nor regular sustainment upgrades to Eglin and Cavalier provide the capabilities offered by the new Space Fence.  The acquisition of the new Space Fence is foundational for the near earth position of the AFSPC balanced space situational awareness strategy.  The planned location of Space Fence in the southern hemisphere will allow it to track objects in low inclinations which provides greater visibility of high value objects in the near earth regime, providing increased battlespace awareness for the Nation and the warfighter. The new Space Fence will provide very precise positional data on orbiting objects and will be the most accurate radar in the Space Surveillance Network.  It will provide enhanced space surveillance capabilities to detect and track orbiting objects such as commercial and military satellites, depleted space boosters and space debris.  The new Space Fence will have much greater sensitivity, allowing it to detect, track and measure an object the size of a softball orbiting more than 1,200 miles in space.  Because it is also an un-cued tracking system, it will provide evidence of satellite break-ups, collisions, or unexpected maneuvers of satellites.  When combined with the new Joint Space Operations Center’s high performance computing environment, the new Fence represents tremendous capabilities in space situational awareness.”


“Both radars are operating as designed and, as with any weapon system, they are periodically upgraded (e.g., software and hardware) to optimize performance.  Additionally, operating procedures are regularly reviewed and modified to address current or emerging operational concerns (you may have heard these referred to as tactics, techniques and procedures).  In this case, a portion of transmissions from both Eglin and PARCS will be used to establish radar ‘fences’ that will enable the detection of space events such as breakups; this capability is currently provided by the AFSSS.  This will enable the transition to our future architecture, which will greatly enhance our space situational awareness, when we award and field the new Space Fence.” 


“There is really no comparison between the contribution of the AFSSS and the capabilities of the new Space Fence.  The loss of the AFSSS will be mitigated by the new operating modes at Eglin and Cavalier.  The new Fence will provide additional capacity, sensitivity and orbital inclination coverage not possible with the AFSSS.”


 “Both PARCS and Eglin already provide much more accurate data than the AFSSS. By using a variety of operating modes at PARCS and Eglin AFB, and developing new procedures across the space surveillance network, we will provide coverage lost by discontinuing operations at the AFSSS.  The fences employed by Eglin and PARCS will help fill the coverage lost by the AFSSS, but it will not completely replace it; however, what we lose in volume of coverage is offset with more-precise data collected by existing radars.” 

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...