So the Navy shot down that dangerous satellite - or was it? Despite assurances from the government that it acted only with the health of the planet in mind, there is enough evidence to raise questions about the government's purpose.

The official reason was a tank of hydrazine, a solid rocket fuel which is toxic and which was part of the defunct secret satellite whose orbit had become unstable. Officially the government was worried that the 40-inch spherical fuel tank would survive re-entry into the atmosphere and break open if it hit land, releasing a toxic cloud. Nor could the government predict precisely when and where the satellite would fall to earth.

Government officials have asserted that this was not an attempt to prove to other nations that we, too, can shoot down satellites if we wish. Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, said this was a one-time event. But arms control experts quoted in news reports saw it otherwise. There is no question that it demonstrates a new U.S. capability, they said. It took workers about a month to reprogram the shipboard missiles for the mission, which means that other missiles could also be reprogrammed if the government wished.

The key piece of evidence against the hydrazine danger idea comes from another part of the government. In its environmental impact statement on the Orion project - the rocket which will replace the space shuttle for transporting people into Earth orbit - NASA notes that the service module right behind the crew capsule will contain hydrazine. This module would be discarded just before the capsule re-entered the atmosphere, and the analysis says the fuel tanks would break open and the propellant would vent before debris reached the surface.

Then there was the Cassini space probe sent to Saturn a few years ago. Because of Saturn's distance from the sun, Cassini was equipped with electricity generators which used plutonium. The possibility of a launch accident spewing highly toxic plutonium over the landscape greatly concerned people. The environmental impact statement for that estimated a 20 percent probability of one of the plutonium generators surviving re-entry intact, and this for a heavily shielded piece of machinery.

None of this evidence is conclusive, yet it's enough to weaken the assertions of the national defense crowd. If it was a test, this incident would be a logical follow to the years of antimissile tests which the U.S. government has carried out since the 1980s when Ronald Reagan first raised the idea of a missile-defense shield in violation of the 1972 antiballistic missile treaty - from which the Bush administration withdrew in late 2001. If it was a test, then it was not a good idea.

The prospect of the United States or any other country possessing an antimissile system in addition to nuclear weapons has always caused concern because it opens the possibility of shooting while being much less vulnerable to return fire. China's complaints about this satellite mission "weaponizing space" are self-serving and hypocritical given that it made its own anti-satellite weapons test in 2001.

Still, a me-too sort of demonstration does not advance the cause of peace; it only fans the flames of militarism and encourages other nations to follow suit, as they followed the United States and Soviet Union in developing nuclear missiles. Instead of making space into a peaceful final frontier, space is now more likely to become like our wild West complete with Indians and six-shooters.