Here on Earth, we reduce, reuse and recycle to keep from sending too much junk to the landfill. But with no recycling bins and no trash cans, evidence of man's journeys into space are starting to pile up.

A report recently published in the National Academy of Sciences states that over the past 50 years, various National Aeronautics and Space Administration (NASA) communities have contributed significantly to the amount of meteoroid and orbital debris (MMOD) floating around above the Earth.

Experts say that there are approximately 22,000 pieces of derelict satellites, equipment and other space junk trapped in the Earth's orbit. And those are just the pieces big enough to track from the ground.

According to retired NASA senior scientist Donald Kessler, on of the report's authors, this space litter is now so prolific it poses a threat to future space missions.

While the report identified many positive aspects of NASA's MMOD programs and efforts including responsible use of resources, it recommends that the agency develop a formal strategic plan that provides the basis for prioritizing the allocation of funds and effort over various MMOD program needs.

But how does one go about collecting large pieces of space debris that are circulating thousands of miles above the Earth?

The report was short on concrete ideas for how this might be accomplished, but according to coverage in the LA Times, possibilities include cosmic versions of nets, magnets and giant umbrellas.

Image: The debris objects shown in the image is an artist's impression based on actual density data. However, the debris objects are shown at an exaggerated size to make them visible at the scale shown. Credit: European Space Agency