Micrometeorites like paint flakes and solidified droplets of antifreeze can damage solar panels on active satellites. Other dangerous debris includes vestiges of solid fuel which float about in space and are highly flammable. They can cause damage and disperse pollutants into the atmosphere if they explode.

Experts say the main worry is that such debris will hit a space station, satellite or other equipment. Space debris orbits around the Earth very fast - about 25,000 kilometers per hour in low-Earth orbit. The junk could cause major damage if it hits satellites or spacecraft.

Because of the high speeds at which objects orbit Earth (up to 8 km [5 miles] per second), a collision with even a small piece of space debris can damage a spacecraft. For example, space shuttle windows often had to be replaced because of damage from collisions with debris smaller than 1 mm (0.04 inch).

Over many decades, the growth in space debris will make orbit operations more hazardous, and more costly. The growth of debris will make tracking and avoiding the debris more complicated, costly, and operationally difficult. It might be tough to perform a mission if frequent maneuvers are required to avoid debris.

Space debris, or space junk, consists of discarded launch vehicles or parts of a spacecraft that float around in space hundreds of miles above the Earth, risking collision with a satellites or a space station. Debris can also be caused by an explosion in space or when countries conduct missile tests to destroy their own satellites by missiles.