The United States is preparing to accelerate its space-based weapons programs and may begin testing within the decade. A space-based laser and a sub-orbital bomber are first on the list.

Pentagon officials are considering those and a number of other technologies to defend growing American space assets and maintain what the U.S. Space Command calls "space control." Defense Secretary Donald Rumsfeld is advocating the speed-up.

The space-based laser research project is slated for live tests in space in 2012, according to the American Institute of Aeronautics and Astronautics. As part of a multilayered national missile defense, SBL could include as many as 40 laser satellites that could defeat enemy ballistic missiles in flight but also could be used to target other space or ground objects.

Another proposal is to develop a sub-orbital bomber that would take off like a long-range missile, travel at 15 times the speed of sound and 10 times the altitude of current heavy bombers, and drop bombs from up to 60 miles over a target, the Los Angeles Times reported. Pentagon officials maintain that such a weapon would not further militarize space because it would be designed to strike ground targets. Nevertheless, it could be adapted to destroy satellites.

In response to such efforts, the international community will continue to seek a treaty banning space weapons. But the United States, unwilling to limit its military options, will continue to argue against such a treaty. Washington already has done so: At the 66-member Conference on Disarmament in June, the United States once again balked at a proposal to ban "all space-based weapons and all weapons attacking outer space from the earth." Without the United States, the leading space power, an international space arms-control regime would be essentially worthless.

Without controls, developed and not-so-developed countries alike will seek ways to build or acquire attack capabilities of their own. Russia and the Commonwealth of Independent States could be on a fast track toward these weapons: The former Soviet Union and the United States prepared for decades for possible space warfare and have conducted considerable research and testing that could quickly be resurrected.

Meanwhile, China is in the process of developing its own anti-satellite (ASAT) weapons, according to U.S. intelligence reports. As other nations advance their own space and satellite programs, they too will have access to these capabilities.

For rival powers and even Western allies, the first step in the space arms race will be to implement a series of passive defensive measures to protect satellites from attack, including hiding, deception, evasion and satellite-hardening techniques. Like the United States, developing countries may create "stealthy" satellites that can be stored in deep space and moved into position only when needed. Russia is most capable of doing this now, but China, India and European countries are not far behind.

Active defense measures are also readily available. For example, electronic and electro-optical countermeasures are available to deflect American space weapons. All space-reliant countries are likely to pursue sensors to monitor the health of satellites.

Also, active countermeasures that are destructive in nature could include satellites with self-defenses, such as a "shoot back" capability. Escort defense could be applied, in which an ASAT weapon would be deployed in orbit to defend an enclave of distant satellites from hostile spacecraft.

Escort defense and "shoot back" capabilities illustrate the fine line between defensive and offensive ASAT systems. Some so-called defensive ASAT weapons could theoretically attack each other. Though defense may be the goal, offensive, or what are called deliberate, ASAT weapons will soon follow.

Many offensive weapons are technologically feasible, given enough financing, or have already been developed by Russia, the United States and China. According to a Princeton University study conducted for the Pentagon, some of these offensive capabilities include co-orbital interceptors, which are basically space mines launched into orbit to take out enemy satellites; direct ascent interceptors launched from the ground or air directly at a space object; ground, airborne and space-based lasers; space-based particle beam weapons; and maneuverable spacecraft outfitted with significant ASAT capabilities.

Countries that lack these capabilities could purchase them. For example, according to the Institute for Foreign Policy Analysis, India is seeking ASAT lasers from Russia. The Council on Foreign Relations predicts that in the future, some countries, including perhaps China and Russia, will form consortia to pool their efforts.

But effective ASAT capabilities do not necessarily have to be high-tech. According to the Defense Department, a recent U.S. Army war game showed that hand-held jammers with ranges up to 150 miles could be used to shut off global positioning systems throughout Iraq, neutralizing many of America's precision weapons.

Poorer countries such as North Korea, Libya, Iran and Iraq could even mount buckshot atop a ballistic missile and launch it into low orbit to destroy satellites as high as 1,500 miles above earth. Meanwhile, a low-orbit nuclear detonation would not harm anyone on earth but would likely fry every satellite in range.

The recent Army war game illustrates how conflicts in the future could quickly spiral into space warfare. In one scenario, China assisted a U.S. adversary with space imagery of U.S. troop movements. The options for U.S. decision makers were limited: either take out the Chinese satellites, bringing China into the war, or do nothing.

The American push for space warfare is likely to outlast the Bush administration. According to media reports, Rumsfeld's top two choices for chairman of the Joint Chiefs of Staff, Gen. Ralph Eberhart and Gen. Richard Myers, both served as commanders of the U.S. Space Command, the most ardent proponent of greater military use of space.

The international community will fail to stop the United States and in turn will be forced to join the quest for space weapons. The United States will lead the new arms race. But as both high- and low-tech space weapons proliferate, the United States, with the most at risk, will also have the most to lose.