By LIYUAN XIAO
In 1978, the Russian Cosmos 954 fell from the outer space and entered into Canadian territory. Its nuclear-powered engine fell apart and caused great potential environmental danger to Canada. Although damages arising from space activities had been stressed by the 1967 Outer Space Treaty and at the 1972 Liability Convention, the Russian Cosmos incident was the first time that people realized how residual debris from space activities may actually influence the environment on earth. The threats of space debris are not restricted to Earth’s environment, but also pose great danger to the exploration of outer space itself. This is important because outer space provides us with a unique environment for collecting scientific data and unrivalled possibilities for research and exploitation, both scientifically and commercially.