WASHINGTON — The U.S. Air Force's decision to shut down a key component of its Space Surveillance Network will weaken the service's ability to accurately detect and characterize objects in Earth orbit, experts say.
The space fence shutdown, ordered by Gen. William Shelton, commander of Air Force Space Command, also will reduce the overall capacity of the system, these experts said. At the same time, they suggested it could increase pressure on the Air Force to award a contract on a next-generation system, which has stalled amid a Pentagon-wide review of its acquisition plans.
According to two recent memos obtained by SpaceNews, the Air Force will shut down the aging Air Force Space Surveillance System, also known informally as the Space Fence, Sept. 1. The memos, from Austin Frindt, a contracting officer with Air Force Space Command, were addressed to Five Rivers Services of Colorado Springs, Colo., operator of the current Space Fence, which consists of a line of VHF radars stretching across the southern United States. [Top 10 Space Weapons]
Deployed in the 1960s, the VHF Space Fence includes three transmitter sites and six receiving stations. It is responsible for approximately 40 percent of all observations performed by the Air Force-run Space Surveillance Network, which includes other ground-and space-based sensor assets, said Brian Weeden, technical adviser at the Secure World Foundation, a nonprofit organization dedicated to space sustainability.
"The Space Fence does a lot of heavy lifting," said Dave Baiocchi, a senior engineer at the Rand Corp., an Air Force think tank in Santa Monica, Calif. Without it, "you're missing some level of accuracy," he said.
In a memo dated Aug. 1, Frindt said the Air Force was not exercising its option for a fifth year of a contract to provide management and logistical support for the nine field stations.
Lori Thomas, president of Five Rivers Services, declined to comment and referred questions to the Air Force.
"This is your notice to begin preparing the sites for closure," the memo said. "A specific list of action items will be provided as soon as it is finalized."
A follow-up memo dated Aug. 9 asked Five Rivers for an analysis of what it would cost to close the Space Fence sites. This memo said the system would be turned off Sept. 1.
In an email Aug. 5 Andy Roake, a spokesman for Air Force Space Command, pointed to the automatic budget cuts known as sequestration. "In this tough, sequestered budget environment, we're considering many options, but for FY14, no final decisions have been made," he said.
The memos suggest otherwise, asking for photographs of the closed sites, plywood on windows and weekly updates. Roake did not respond to follow-up questions by press time. A spokesman for the U.S. Strategic Command, which oversees the Joint Space Operations Center, referred questions to Space Command.
Though part of a broader surveillance network, the VHF Space Fence is crucial because it can track objects up to 24,000 kilometers away. Other ground-based sensors in the network generally track objects at altitudes lower than a few thousand kilometers, Weeden said.
"The Space Fence is very important as it gives an 'uncued tracking' capability," Weeden said. "Because it's constantly transmitting, it can detect objects without being tasked to do so. There are some other sensors in the network that can do uncued tracking to some degree, but the Space Fence is rather unique in the sheer size of the detection coverage it has."