So this is how the war in space might begin: not with a bang but a clank. On April 15, more than 450 miles above Earth, an experimental NASA spacecraft called DART (Demonstration of Autonomous Rendezvous Technology) fired its thrusters and closed in on a deactivated U.S. military communications satellite–and then gently bumped into it.
That wasn't supposed to happen. The approaching craft had calculated its dwindling distance with lasers and was supposed to merely close in on the satellite and maneuver around it. This would demonstrate what are known as proximity operations, or "prox ops," a key component of future satellite servicing. Instead DART demonstrated another key component of future satellite warfare: bumping into things. The first sign of trouble came when DART mysteriously shut down. At first, NASA ground controllers guessed that it had run out of fuel while it was still a few hundred feet from the satellite. But five days later, an Air Force tracking system spotted the target satellite in a new, higher orbit, making obvious the fact that DART had collided with the satellite. As a test intended to pave the way for new technologies to service orbiting satellites, this was an abject failure. But as an inadvertent demonstration of a basic but potentially devastating space-combat tactic-disabling enemy satellites by ramming them into useless orbits-the mission was a surprising triumph.
Will the Pentagon be carefully studying the DART data? Bet on it. The conquest of space has always served two essential purposes: scientific and technological advancement, and military advantage. It is a poorly held secret that NASA and the U.S. Air Force routinely transfer technologies back and forth between scientific and military programs. As DART demonstrated, virtually every system envisioned by the U.S. to extend our reach in the solar system also has a potential offensive use, from DART 's own autonomous rendezvous technology to communications and geographic survey systems that have been evolving for the past four decades. Even the spectacular Apollo lunar landing 36 years ago-executed by Air Force test pilots-was a thinly veiled effort to beat the Soviets to the moon and send a clear message of space superiority. Today, President George W. Bush is every bit as interested as John F. Kennedy was in gaining the upper hand in space. The White House will soon issue a new national security directive that will bring the nation a significant step closer to fielding weapons up there.
What those weapons will be will depend on how well the technology develops, but potential future systems include space planes capable of striking targets anywhere in the world in a matter of hours, 20-foot-long satellite-launched "rods from God" that fall from the sky with tremendous force, orbiting mirrors that flash laser beams to distant targets, electromagnetic-pulse weapons that fry satellite electronics, "tugboats" that push satellites into new orbits, satellites that spy on other satellites, and microsatellites that disable or destroy larger satellites.
Among the most pressing demands that space access can alleviate is high-speed, worldwide delivery of weapons. Future hypersonic unmanned space planes will use the advantages of spaceflight to strike anywhere in the world within two hours, a capability dubbed "prompt global strike." The Air Force envisions a system that consists of two vehicles: one to make the trip, and a second to deliver the bombs. Initially, a small rocket will serve as the launcher, and the bombs could be carried on board a gliding, self-steering vehicle with a 1,000-pound payload called the Common Aero Vehicle (CAV).
Later, in maybe 15 years, the Air Force plans to replace the rocket launcher with a reusable hypersonic cruise vehicle capable of carrying 12,000 pounds up to 9,000 miles. The unmanned aircraft will take off from a runway and use a scramjet engine burning liquid hydrogen to reach hypersonic speeds. The engine will be repeatedly shut down and re-ignited to send the craft skipping across Earth's upper atmosphere like a stone. The vehicle could deliver multiple CAVs or other payloads.
A program called Falcon is a testbed for some of these technologies. Jointly sponsored by the Air Force and the Defense Advanced Research Projects Agency (DARPA), Falcon is developing a Small Launch Vehicle and Hypersonic Technology Vehicles to demonstrate possible propulsion systems.
Developing a global strike capability isn't just a technological challenge-it's a political one as well. One big concern is that the leaders of countries such as China and Russia might have a hard time convincing themselves that the U.S. wouldn't hide nuclear weapons inside a CAV gliding at Mach 20. Sensitive to this concern, Congress has directed that none of the funds allocated for CAV research be used to develop or test a vehicle that includes any nuclear or conventional weapon. The decree leaves the Air Force in the awkward position of developing a weapons carrier that won't carry weapons.
As for weapons that will actually reside in space, as opposed to just passing through it, perhaps the most feasible and economical, at least in the short term, are microsatellites. (A microsatellite is simply any satellite weighing about 100 kilograms, or 220 pounds. Full-size satellites typically weigh at least 10 times that much.) Two programs are paving the way for such devices, which could one day conduct offensive military missions in orbit. Just a few days before the DART fender bender, the Air Force Research Laboratory launched a microsatellite known as Experimental Spacecraft System 11, or XSS-11. The clumsy DART experiment didn't bode well for the long-term success of XSS-11, which was also designed to conduct prox ops in orbit. "If we touch another object, we fail," says XSS-11 program manager Vernon Baker. First on the schedule was a rendezvous with the spent upper stage of the Minotaur rocket that carried the microsatellite into space. That was successful, and XSS-11 will spend more than a year visiting other objects in space.
Meanwhile, DARPA is working on a program called Orbital Express, in which a prototype servicing satellite will rendezvous with a prototype serviceable satellite in orbit to prove that the two can dock autonomously. Orbital Express, which is scheduled for a September 2006 launch, will also demonstrate on-orbit refueling.
Put XSS-11 and Orbital Express together, and you get a host of potential applications. Imagine a microsat that could fly up to a larger satellite and perform on-the-spot parts replacements and upgrades. Microsats could even be used as "bodyguards" for other satellites. "If you had multiple ones of these, you could basically make a fence," Baker says. The Air Force doesn't like to talk about offensive applications, but they aren't hard to imagine. "One of the most effective threats is a microsatellite in the form of a 'space mine,' " warned Richard L. Garwin, a prominent national-security expert with the Council on Foreign Relations, at a 2003 conference on space weapons. Microsatellites make good antisatellite weapons because they can easily maneuver to within lethal range of a satellite and then sit there ready to explode on command.
A space mine wouldn't necessarily even have to explode to be effective. In fact, an explosion might scatter debris that could prove deadly to friendly satellites. Instead, a space mine could simply shut down a larger satellite by zapping its electronics with a burst of electromagnetic energy. A microsat capable of attaching itself to a larger satellite could even act as a parasite-disabling the satellite, tampering with it, or blocking its view.
From a military perspective, the beauty of such weapons is that an enemy might not even know they're there. Microsatellites can be launched as secondary payloads on unrelated missions. And in the future, even smaller satellites-nanosats, weighing only around 22 pounds-will be able to do the kind of proximity and docking operations planned for today's microsats. It would be especially difficult to detect nanosats in geosynchronous orbits, 20,000 miles above the Earth, where many communications satellites are located.
Of course, the same advantages will apply to our opponents should they develop similar technology. One of the nations most interested in small satellites is China, which launched its first microsat, Tsinghua-1, in 2000. China has partnered with Surrey Satellite Technology, a British company at the forefront of microsatellite development, to field maneuverable microsats. Like XSS-11, these Chinese microsats are being developed for peaceful purposes but may be able to switch seamlessly to playing offense. From the ground, it would be difficult to tell the difference between a scientific microsat and a space mine.
Tracking such threats will be critical to waging an effective war in space, which is why the Air Force plans to launch a satellite called Pathfinder as early as 2008. Like other spy satellites, Pathfinder is basically a high-powered telescope. But rather than scanning objects on the ground, Pathfinder will examine other objects in space to identify any debris or foreign satellites that pose a risk to U.S. spacecraft. Eventually, a constellation of spysats-collectively known as the Space-Based Space Surveillance system-could join Pathfinder, gathering intelligence.
An Unclear Future
The goal of all these systems is what top brass call space superiority. "The threats we face are very real and dangerous," said General Lance W. Lord, Commander of the U.S. Air Force Space Command, during Congressional testimony in March. "As our dependence on modern space capabilities grows, the need to establish and maintain space superiority also grows proportionally, if not exponentially."
But who are our opponents in space, and what is the threat? Lord and others point to attempts by the forces formerly working under Saddam Hussein to jam GPS satellite signals during Operation Iraqi Freedom and thereby send U.S. precision bombs off course. U.S. forces, however, easily defeated those rudimentary efforts. And while China and Russia are experimenting with technologies such as microsatellites, there is little evidence so far of any serious threat to U.S. spacecraft-although it is clear that ostensibly benign partnerships with our allies, including that between China and Surrey Satellite, could lead present and future adversaries to the development of advanced space technologies.
The Bush administration feels that the U.S. must seize control of space before it falls into enemy hands. But experts within and outside the military contend that this country has the most to lose by starting an arms race in space. The U.S. has far more satellites in orbit than any other nation, yet these satellites are largely undefended. As John Pike, director of the Virginia-based think tank GlobalSecurity.org, puts it, "People who live in glass houses should not organize rock-throwing contests."
Pike and other critics further caution that any moves to weaponize space will only legitimize future efforts by others to develop antisatellite technologies-and will turn the U.S.'s asymmetrical advantage into a vulnerability. For now, the focus of American offensive efforts is on technologies designed to reversibly incapacitate an enemy's space hardware. For example, the Pentagon's new mobile, ground-based Counter Communications System is said to be capable of temporarily jamming an enemy's satellite communications.
As for whether the visions being floated within the Pentagon even have a chance at succeeding, the reality is that the Air Force has a long history of seeking exotic space weaponry, with only marginal results. In 1958 General Homer Boushey proposed stationing nuclear missiles on the moon, apparently forgetting that they would take three days to reach the Soviet Union from there. Since then, the Air Force has proposed a lunar military base, a manned military space station, several different space planes, and a variety of other technologically (and financially) ambitious programs, all aimed at taking the ultimate high ground.
Many space-based systems under development are embarrassingly over-budget and behind schedule. In July the Government Accountability Office delivered a blistering report to Congress, and the GAO's director of acquisitions and sourcing management, Robert E. Levin, testified that technologies such as space-based radar and missile-warning systems are costing more and taking much longer to develop than promised when initially approved.
Although the Air Force is not yet deploying weapons that can blow things out of the sky, it continues to experiment with such systems in its biennial Schriever war games, which began in 2001 and are named after General Bernard A. Schriever, who headed the nation's military-satellite and ballistic-missile development programs in the 1950s. Results from the Schriever games-the teams using simulated space weapons have been particularly successful-have convinced many strategists that such weapons are a must-have for future warfare.
General Schriever, who died this past June, made headlines in 1957 when he gave a keynote address calling for U.S. space superiority. He received a severe reprimand from the Eisenhower administration, which had proclaimed space to be a peaceful commons. Fifty years later, though, U.S. space policy may be headed precisely in Schriever's direction.
Is it legal to weaponize Space?
Although space is not yet weaponized, it is most definitely militarized. Satellites are routinely used
for military communication, navigation, spying and weather forecasting. Taking the military presence
in space to the next level-with active weaponry-is not quite the legal quagmire you´d think it would be. The Outer Space Treaty of 1967 prohibits nations from placing nuclear or other weapons of mass destruction in space, but there are no international laws against other types of space weapons.
Dawn Stover is Popular Science's science editor.