When China destroyed one of its own satellites in space six years ago, it alarmed many other Asia-Pacific countries that have invested heavily in orbiting satellites for telecommunications, Earth observation and scientific research.
China's action caused particular concern in the United States, Japan, Australia, India and other nations that use satellites for defense purposes that can include voice and data communications, surveillance, precise navigation and guidance of bombs and missiles.
In 2008, just over a year after the Chinese test, the U.S. fired a modified ballistic missile defense rocket from a warship to shoot down a malfunctioning American spy satellite about 250 km above the Pacific Ocean. Washington said that the operation was essential to prevent the bus-size craft and its toxic fuel from crashing back to Earth, possibly causing death, injury and damage.
While space has long been used for military reasons, it is not yet a place for stationing weapons — a development that would create a new and highly volatile frontier of international rivalry and geopolitical tensions. Some Western and Asian analysts believe that China may be planning another test of a weapon designed to destroy or damage a satellite in orbit or interfere with its functioning.
The Global Times, an often-nationalistic newspaper published by the People's Daily, flagship of the ruling Chinese Communist Party, said in an editorial on Jan. 6 that the U.S. advantage in space was currently "overwhelming." It pointed out that America had so far refused to negotiate on a treaty to outlaw arms in space that was first proposed by China and Russia in 2008.
Washington says such a treaty could not be verified and that the U.S. needs freedom of action in space. The Global Times said that China therefore needed "an outer space trump card" by showing it could threaten U.S. superiority.
The newspaper added that "against this background, it is necessary for China to have the ability to strike U.S. satellites. This deterrent can provide strategic protection to Chinese satellites and the whole country's national security."
Is the world on the verge of a potential space warfare era in which weapons are based in space with the capability to attack targets there or on the ground?
The U.S. Department of Defense, in its 2012 report to Congress on Chinese military developments, accused China of "developing a multidimensional program to limit or deny the use of space-based assets by adversaries in times of crisis or conflict."
China's test on Jan. 11, 2007, of an anti-satellite (ASAT) weapon to shoot down an aging Chinese weather forecasting satellite in low-earth orbit about 850 km high showed that it had the capability to strike spacecraft in the most widely used satellite traffic belt.
Nearly half of the world's approximately 1020 operational satellites are in low earth orbits, those below 2,000 km. They include spy satellites that need to be relatively close to the surface of the land or sea to take high resolution photographs and other images that are of intelligence and military value.
The Chinese test ended a long period of restraint by the main space users. Only two nations, the former Soviet Union and the U.S., had previously destroyed spacecraft in anti-satellite tests. America's last test was in the mid-1980s.
As it turned out, China's 2007 ASAT test was not its first, or the last. On Jan. 11, 2010, China fired a similar rocket to the one it used in 2007, but this time as a missile defense test. The intercept occurred at a much lower altitude of about 250 km than the 2007 test and targeted a dummy warhead launched by a ballistic missile instead of a satellite in orbit.
However, there is no technical difference between ASAT interceptors and missile defense interceptors that work above the atmosphere in outer space. For space treaties, the atmosphere is defined to end and outer space to begin at an altitude of 100 km above sea level.
A U.S. State Department cable on China's 2010 test was published by WikiLeaks in March 2011. According to the cable, China carried out flight tests of its direct-ascent anti-satellite interceptor rocket in 2005 and again in 2006.
The Pentagon says that in addition to the direct-ascent anti-satellite weapon that the Chinese military used in 2007 to destroy a satellite, China's counter-space capabilities also include jamming, laser, microwave and cyber weapons.
Its 2012 report to Congress said that over the past two years, China had conducted increasingly complex close proximity operations between satellites, while offering little in the way of transparency or explanation.
China's 2007 test also raised international concerns because the wreckage left more than 3,000 pieces of space debris that are a hazard to operational satellites. Both the satellites and the debris orbit at very high speeds, increasing the risk of collision.
China plans to put many more satellites into low, medium and high orbit above earth, for civilian and military purposes, consolidating its place with the U.S. and Russia as one of the world's three leading space powers.
The 1967 Outer Space Treaty bans the stationing of weapons of mass destruction in space but not anti-satellite weapons.
In an effort to break the deadlock between the U.S. on the one side and China and Russia on the other, the European Union has drawn them and about 40 other countries into negotiations on an international code of conduct for outer space activities.
The EU wants to finalize the voluntary code in 2013. The aim is to limit further space debris, improve international cooperation and create a "peaceful, safe, and secure outer space environment."
Whether such a code, which would not be legally binding, could by itself prevent an arms race in space is doubtful.
However, as China's reliance on orbiting satellites grows to match that of the U.S. and Russia, their mutual interest in stability may prevent conflict in outer space, just as fears of mutually assured destruction have helped to prevent nuclear warfare since 1945.
Michael Richardson is a visiting senior research fellow at the Institute of South East Asian Studies in Singapore.