The US, Australia and Canada are concerned over a Chinese test to shoot down a satellite, the first such test in 20 years, state media reported. China used a ground-based medium-range ballistic missile to knock out an aging weather satellite some 537 miles above the earth. The missile slammed into the satellite on January 11. The last time this kind of test was carried out was by the US in 1985. America was reportedly not surprised by the demonstration of this Chinese capability. The US has been researching its own satellite killers, and has also looked at ground-based lasers that could disable or destroy orbiting craft.