The United States is Taiwan's security guarantor against any possible Chinese invasion. But the recent successful test of a Chinese satellite destruction missile raises the prospect of Beijing scuttling America's critical satellite network in a possible war.

"The prospect of losing a good chunk of our satellite coverage, our satellite network in space in a Taiwan combat scenario really does change the equation for American planners on how we approach the defense of Taiwan should it need it," John Tkacik, a former State Department expert on China, told AFP.

Taiwan has several satellites up in orbit now, including two imaging ones used for intelligence and surveillance purposes.

If the Chinese pursued the satellites during hostilities, it could cause Washington to have second thoughts about getting involved.

"If especially the United States felt that its satellites were equally vulnerable, it's a disturbing new development," said Tkacik, the former chief of China analysis in the State Department's bureau of intelligence and research.

US officials revealed last week that China had destroyed one of its own orbiting weather satellites earlier this month using a ballistic missile, making it the third country after the former Soviet Union and the United States to shoot down an object in space.

In Beijing, foreign ministry spokesman Liu Jianchao confirmed the test on Tuesday and said it had already notified Washington.

He insisted however that China never has, "and will never, participate in any form of space arms race."

The successful test -- the first such intercept in more than 20 years -- means China can theoretically shoot down spy satellites or other orbiters operated by other nations, sparking fears of a space-based arms race.

"There has been long a desire on China's part to try to have weapons to shoot down or at least interfere with American satellites which America depends upon in order to meet its defense commitment in Asia," said former senior Pentagon official Dan Blumenthal.

"So it very much puts in the minds of American planners, policy makers how to overcome this now more costly commitment," he said.

Blumenthal said Taiwan will be a "central" issue of the China's satellite-killing capability because the most likely flashpoint between Washington and Beijing is over Taiwan, which China considers a renegade province.

Amid the active competition in space, "the United States is going to be taking countermeasures to protect its satellite constellations," he said.

Stratfor, an American security and intelligence think-tank, said Beijing's first attempts to control space would not be an effort to match US capabilities but "rather to become master of its own domain above East Asia.

"Facing the major competitor in all of space, China will tailor its offensive space capability specifically toward countering US dominance -- at least in part," it said.

Japan and other challengers to Beijing's regional hegemony, however, will not be far behind, Stratfor added.

The United States has a military alliance with Japan, which harbors US troops mostly in Okinawa, strategically close to the Taiwan Strait.

Since the Persian Gulf War about 20 years ago, Washington has been saying that the strategic center of American military and naval power is its space networks.

"The way that the United States communicates, transmits data, gets a picture of the battle space, gathers 90 percent of its intelligence, is through its space networks. And without that we are blinded, we are made deaf and dumb, and you simply couldn't function," Tkacik said.

He said space networks were particularly crucial to defending Taiwan and Japan.

"If it was just a local conflict and we are suddenly blinded, I think we could handle that. But in a large area like Okinawa, Taiwan, Taiwan Strait, I think it would be very difficult to communicate between ships and (from) aircraft to ships to find out where the enemy is," he said.

The US Defense Department says China is spending two to three times more on its military than the 35 billion dollars a year it has acknowledged.

A department report last year concluded that while Taiwan appears to be the near-term focus of China's military spending, the build-up poses a potential threat to the United States over the longer term.

China has consistently maintained that its military build-up is for defensive purposes only, while claiming that it has no history of invading other countries.