Spacecrafts have to be very strong to withstand the elements of space. One problem of space travel that does not receive as much attention as it does on Earth is pollution. Of the approximately 8500 satellites orbiting the Earth, only 5% work. Most of these belong to the United States and Russia. Other countries have filed complaints against the U.S. and Russia through the United Nations,due to their own need of geosynchronous satellite orbits. (Brown, 1996)
In space, satellites and spacecrafts take a beating. They must contend with radiation, erosive matter, the pelting of meteroids, thermal cycling (hot and cold every 90 minutes), ultraviolet radiation, a vacuum, atomic oxygen and tiny fragments of space hardware. (Canby, 1991)
We humans have not only managed to pollute the Earth, but outer space as well. Parts of failing satellites have released all kinds of debris. For example, a hazard of low-Earth orbit could be just a tiny paint chip. Man-made debris numbers in the billions. A speck of paint the size of a grain of salt, caused a pit—200th’s of an inch deep one of the Shuttle Challenger’s windows and it had to be replaced. Through 1990, 17 shuttle windows, at a cost of $50,000 each have had to be replaced due to damage from man-made objects in outer space. (Canby, 1991)