In January 2007, the Chinese military launched a missile 500 miles into space, shattering an orbiting satellite. The assault was only a test that took out one of China's own weather satellites. But it sparked an international outcry over the country's willingness to use weapons in space. A spokesman for the U.S. National Security Council called the test "inconsistent" with efforts for international cooperation.
Military experts have since become concerned that space could become the next battleground for global conflicts. Of particular concern is the lack of visibility with some missile strikes, such as China's in 2007. Some experts say that if an enemy were to launch a similar attack against an American satellite over the Southern Hemisphere, the U.S. military might not know about it. The southern half of the world is something of a blind spot for military space tracking systems, say both senior defense officials involved in space policy and private satellite operators.
"If a collision happens down there, you don't see it," says Paul Graziani, president of Analytical Graphics, which makes systems used by the military to operate and guide satellites. "It takes 45 minutes for the satellite to come back into the Northern Hemisphere. We would be expecting to see a satellite coming around whole but instead just see a bunch of pieces."
The U.S. military uses land-based radar to track its satellites, but it has no such radar installations in the Southern Hemisphere. The gap is a legacy of the Cold War, when the U.S. was focused on missile threats from the Soviet Union, and there were no nuclear-armed adversaries in the Southern Hemisphere.
Flying Blind Below the Equator? The Defense Dept. agrees that it lacks what it calls "space situational awareness" in the skies. Pentagon officials say they are in negotiations with Australia to install radars on that continent, filling in at least part of the Southern Hemispheric blind swath. They are also looking at upgrading the power of existing radar and using space-based telescopes to track satellites.
"Adequate situational awareness is necessary to act appropriately in any military scenario," says Commander Bob Mehal, spokesman for the Defense Dept. "Our current capabilities do not allow for continuous observation of all space objects at all times."
The military wants to improve space situational awareness, but needs more funding to upgrade the tracking systems.
The Pentagon's inability to get a complete picture is the subject of a current review panel of military space operations, according to the 2009 National Defense Authorization bill, which called for the panel. Experts say such a review is long overdue. "It's about time that the military take seriously the need for space situational awareness," says Ray Williamson, executive director of the Secure World Foundation, a space policy think tank. "The question they are asking: 'Are we prepared for the possibility of an adversarial attack [on our satellites]?' I think the answer is no."
More Than 20,000 Objects Orbit Earth The U.S. military is heavily reliant on satellite systems for communications, the targeting of sophisticated weapons, and spying, with 104 active military satellites. In recent years the military has used satellites to guide unmanned Predator drones that launched missiles to assassinate suspected militants in the border regions of Pakistan and Afghanistan. The loss of a single spy or communications satellite could have a serious impact on military readiness because many systems don't have backup. The massive scope of U.S. military operations, which span five continents, makes space-based communications hubs essential, say experts. "We rely on satellite communications like no other military," says Dean Cheng, a senior Asia analyst at CNA, a think tank that researches military strategy.
Radar systems track more than 20,000 space objects that orbit the earth at 17,000 miles per hour. The Air Force works with such private satellite providers as Orbital Sciences (ORB), Intelsat, Lockheed Martin (LMT), and allied countries to help avoid collisions. But satellite companies and military officials say that blind spots in the tracking system could allow for an unseen attack by a hostile state.
"Our greatest concern," says a senior defense official who spoke on the condition of anonymity, "is that space situational awareness is not good enough to attribute cause to the degree that a President or the Secretary of Defense can make a decision on a course of action."
Last February’s crash of an Iridium communication satellite, used by the military and private sector, with a defunct Russian satellite, highlighted the vulnerability.The accident over Siberia was the first known crash between two satellites. But experts say near crashes are increasingly common as more hardware goes into orbit. "[The collision] showed we weren't doing enough to keep an eye on satellites that we depend on," says Williamson. "It's a question of getting along for a long period of time with a problem that you don't pay attention to and doesn't hurt you—until it does, and then you pay attention. It was a wake-up call."
Developing Anti-Satellite Weapons Many satellites orbit in a north-south path around the earth. As they pass over the Southern Hemisphere, they vanish from existing U.S. radar. If a satellite were hit by a missile in the Southern Hemisphere, the U.S. military might be able to track a culprit missile fired from the earth's surface because the Pentagon monitors heat patterns such as those caused by missile launches. But if the attacking missile were launched by say, an aircraft or rival satellite, it would be far more difficult to trace its origins. "Many people do not think we have the level of competence to determine that an incidence involving the destruction of a satellite was caused by someone's deliberate action vs. space junk vs. a natural phenomenon," says Cheng.
China, Russia, and the U.S. have tested anti-satellite weapons and could develop the ability to launch such an attack from an airborne vehicle or from a satellite, say experts. If such an attack destroyed a U.S. satellite in the Southern Hemispheric blind spot, "attribution would be very difficult," says the senior military source.
That scenario worries U.S. military planners because Pentagon strategies rely on the ability to deter possible enemies with the threat of retaliation. The military would hardly be able to threaten to strike back if it lacked the capacity to identify an attacker. "We cannot hope to set up a system of taboos if we can't attribute actions," says the senior military source.