Two months ago, China fired a medium-range missile into space to destroy one of its own weather satellites in low Earth orbit, attracting the attention of many in the strategic community.
For some, the Jan. 11 test revealed China’s increasing military capabilities and an emerging threat to U.S. dominance in military space. For others, the test proved the need for a U.S. anti-satellite capability. The conventional wisdom was that the United States needed to create such a system to deter the Chinese from doing anything rash in an international crisis — in effect, bringing mutually assured destruction to military space operations.
The reality is different from the conventional wisdom, according to knowledgeable space experts and former intelligence officials. They say the United States already has an anti-satellite capability — just not the kind that China displayed in January.
Rather than a kinetic approach, say officials and experts, the United States has adopted a method that relies on spy satellites’ most vulnerable aspect: the need for constant housekeeping from the ground.
To maintain satellite orbits, particularly low Earth orbits, controllers on the ground must send their satellites a constant barrage of signals from ground stations around the world. For example, the United States maintains the Satellite Control Network, a string of eight tracking stations in places as remote as Thule Air Base on Greenland, and Diego Garcia in the Indian Ocean.
By interfering with those signals — called telemetry, tracking and control signals — the United States can put satellites out of commission for critical periods of time or send them spiraling out of control. Intelligence experts call the strategy “electronic negation” or “intrusion.”
"The best ASAT [anti-satellite device] is not a weapon that detonates next to an enemy satellite," said William E. Burrows, a journalism professor at New York University who is also the author of "Deep Black," a book on spy satellites. "Instead, it would be a signal that would tell the satellite to take the rest of the afternoon off."
Such a device is best for a number of reasons, experts say. Sending up a flurry of ASATS —missiles or space mines — would be obvious and could start an arms race in space or trigger a war in a crisis. Blinding an adversary has had that effect for eons. Using signals intelligence and intrusion is far subtler, and thus more difficult for the victim to detect.
Soviet-era skulduggery
The technology is not new. The Soviet Union first employed such interference against the United States more than 30 years ago — along with their own kinetic ASATs.
“In the 1970s, the U.S. noticed that once a Marisat satellite (a maritime communications satellite) was outside the range of tracking stations in the continental United States, it was turned off,” an intelligence expert familiar with the operations told MSNBC.com on condition of anonymity. “Once it came back into range, it was turned back on.”
The United States immediately suspected that the Soviets had sent signals to the satellite causing the outage, the expert said. (The choice of the Marisat was interesting. The Soviets suspected — correctly — that it was used by American agents operating in the Soviet Union to communicate with the CIA.)
Addressing the threat
Jeffrey T. Richelson, author of a dozen books on U.S. and Soviet intelligence capabilities, said the United States understood the threat. He points to a 1977 memo from Brent Scowcroft, then national security adviser, to the secretaries of state and defense as well as the director of the Arms Control and Disarmament Agency on “U.S. Anti-Satellite Capabilities.”
The memo once classified “Top Secret” but now available at the Gerald R. Ford Presidential Library (and online) lays out presidential fears of Soviet dominance in the area and the means to counter it. “The Soviets should not be allowed an exclusive sanctuary in space for critical military supporting satellites,” Scowcroft wrote.
Scowcroft, on behalf of the president, proposed a twofold strategy. The more obvious solution was to be pursued in the open—the acquisition of an low-orbit anti-satellite interceptor capable of destroying “a small number (6 to 10) of important military satellites within a period of one week.”
But the “fact of” an electronic ASAT capability — one that would “electronically nullify critical Soviet military satellites at all altitudes up to synchronous” — was to be “classified and special compartmented,” meaning kept at the highest security level possible. The reason: “to avoid stimulating” counter measures by the Soviets.
Using signals instead of missiles
The proposal to develop an anti-satellite missile had little immediate effect. Scowcroft's national security memo was dated just two days before the end of the Ford administration, and the Carter administration had little interest in the ASAT interceptor idea. (In the 1980s, the Reagan and the first Bush administration renewed interest in the kinetic ASAT — including one that would be launched from an F-15 — but didn’t deploy anything.)
But the idea of creating a “electronic negation” or “intrusion” capability never waned. And the United States had all the means necessary to carry it out. The U.S. military had its own electronic intercept satellites as well as worldwide network of ground stations.
“The United States has had a variety of intercept capabilities both in space and on the ground to monitor Soviet communications with its satellites,” Richelson said. “There were ground stations in the U.S., Europe, and Asia monitoring Soviet satellites.”
In Europe, there was the mammoth ground station at Menwith Hills in England; in Japan, there was a more remote but no less important site in Misawa; and in the hills of western North Carolina, near the town of Rosman, was another critical facility — which has since closed.
“Depending on encryption and whether you could read the signals, they could be telling the satellite what to do, how to maneuver, reporting on its health, etc.,” Richelson said. “That is the first step in intruding on someone else’s satellite … being able to monitor it, and then ideally you could send your own signal to take their place.”
Blocking a satellite’s view
By the 1990s, the United States had another secret means to negate an adversary’s satellite: simply stepping in front of it.
Intelligence experts described a success the United States had with what is a basic but not kinetic strategy. In November 1990, the Pentagon launched an experimental and highly classified satellite nicknamed "Prowler" on the space shuttle Atlantis.
According to one expert's account, Prowler stealthily maneuvered close to Russian and presumably other nations’ communications satellites in high Earth orbit, 24,000 miles (38,400 kilometers) up. Such satellites are ideal targets. They are at much higher altitudes and are thus difficult to track visually. Many key military satellites are in this orbit — relay satellites that transmit the imagery from spy satellites as well as military communications satellites, weather satellites, and electronic eavesdropping satellites that target terrestrial microwave communications.
By some accounts, Prowler gathered all manner of data on its target satellites: their size, measurements, radar signature, mass and the frequencies on which they relay their data.
Knowing all that, a satellite using Prowler technology would not have to jam the other satellite's signals or destroy it with a space mine. Rather, Prowler could simply step in front of it and block its signals. One expert, speaking on condition of anonymity, claimed that Prowler did just that in tests using U.S. communications satellites without being detected.
Capabilities debated
How close can such a U.S. satellite get to another satellite? Within about a foot, the expert said. What's more, Prowler technology can permit the satellite to maneuver close to the target without receiving data from earth. Once within a certain range of a target, the Prowler could resort to an internal computer program.
Since then, there is no indication that the U.S. has launched other such Prowler satellites, but the technology exists. NASA flubbed a robot rendezvous in 2004 when an active satellite accidentally struck, but didn’t damage, its target satellite.
Experts say the U.S. military appears to be continuing its satellite-jamming experiments, even though the details are classified. Richelson pointed to a 2004 decision by the Air Force to take yet another ASAT program “black,” meaning classifying it at a high level. The Counter Surveillance Reconnaissance program has an amorphous mission — “interfering with an adversary’s access to space-based reconnaissance.” What that means, Richelson suggested, is a program “designed to jam signals from getting from the satellite to the ground.”
Added to programs that intercept control signals, such a system could render an adversary’s satellite capability worthless without firing a shot. Richelson also notes that there is an unappreciated downside for kinetic ASATs: The debris field created by a successful attack could interfere with your own satellites, tearing them apart.
Worrying about the dangers
Many in the arms control community have long worried about the dangers of either the kinetic or electronic program.
“We are not without our own capabilities,” said John Pike, a policy analyst at GlobalSecurity.org. “Several of the anti-missile systems we are deploying can do the job. Electronically, we have had the capability to jam data links for sometime. It’s just not that hard for a superpower.”
The problem is whether you want to try the jamming strategy in a crisis, since the method doesn't appear to have a track record against spaceworthy rivals.
“A kinetic ASAT has high confidence. It works,” says Pike. “The downside of the non-kinetic is the question of what your confidence level is.
“Non-kinetic solutions can be difficult to test in peacetime because there is no point in testing on your own system. I can build representative targets that I can [use to] test the kinetic. It’s more difficult to do that with a non-kinetic solution because the way the adversary’s satellites operate in peacetime may be different in a crisis. You can test it in peacetime, only to discover it’s completely worthless in a crisis.”
And then there is the danger of getting caught. “If I am testing my own against my own target, fine,” Pike said. “But if I am poking around in somebody else’s command link, now you’re meddling, and you have to think carefully about doing that.”