Scientists have predicted that the maximum number of people the Earth can sustain is somewhere between nine and ten billion. Current population is estimated to hit nine billion by the year 2050. So humans have roughly 32 years before overpopulation becomes a really, really big problem.

But, where else can we go?

People around the globe have developed space agencies for exploration (think Elon Musk, Jeff Bezos, etc.). There are private companies sending rockets and satellites into low orbit. We’ve been to the moon and back.

It is clear that our intention is to colonize the only place left: space.

However, can it be that easy if we have already filled space with our junk?

The Problem Of Space Pollution

NASA scientist Donald Kessler warned in a paper written in 1978, that every collision of man-made objects in space generates more shrapnel and debris as pieces fly apart on impact. The effect is cumulative, as new debris collides with other objects it creates even more debris.

Ultimately, space will become impassable because of the continuous cascade of colliding debris, including destruction of telecommunications systems and nullifying of further space launches.

Twice every year, if not more frequently, the International Space Station moves to avoid a hypothetically disastrous crash with space junk.

Estimations vary, but there are approximately 4,000 active and inactive satellites in space. They could be hit by the 500,000 bits of floating space debris, some micro-millimeters in size, all the way up to pieces the size of two double-decker buses.

Space debris encompasses both natural (meteoroid) and artificial (man-made) particles. While meteoroids orbit the sun, most man-made debris orbits the Earth. Therefore, the man-made junk is usually called orbital debris.

These include broken spacecraft, abandoned launch vehicles, manned mission-related debris, and disintegration debris.

Estimates suggest that more than 20,000 items of debris larger than a softball currently orbit the Earth. They travel up to 17,500 mph, which would allow a relatively small piece of orbital debris to seriously damage a satellite or a spacecraft. Additionally, there are 500,000 pieces of debris marble-sized or larger. There are millions of pieces of debris too small to be tracked.

“The greatest risk to space missions comes from non-trackable debris,” said Nicholas Johnson, NASA chief scientist for orbital debris. The Department of Defense sustains a hyper-accurate catalog on objects in Earth orbit bigger than a softball.

Are you starting to get the picture? There’s a lot of stuff in space that can cause serious problems for space travelers.

Space Debris and Human Spacecraft

More than 500,000 pieces of debris, or “space junk,” are tracked as they orbit the Earth.

The increasing amount of space debris multiples the danger to space vehicles, but particularly the International Space Station, space shuttles, and other spacecraft with human passengers.

NASA monitors space debris to predict collisions and uses a long-standing set of guidelines to prepare for such events. These guidelines are part of the existing flight rules and specify that when a piece of debris becomes close enough to increase the probability of a collision, evasive action or other precautions are put in place to ensure the safety of crew members.

Often times, there is plenty of advance notice, which allows for time to move the station slightly (called a “debris avoidance maneuver”). Other times, the tracking data does not give a precise enough targeting of debris or a close pass isn’t identified in time to make orbital adjustments.

When that happens, the control centers around the world may agree to move the crew into the Soyuz spacecraft used to fly humans to and from the station. The crew would then have the ability to leave the station if a collision occurred and caused a loss of pressure in the life-supporting module or caused critical damage.

Debris avoidance moves are primarily small and occur between one and several hours prior to the predicted collision. These maneuvers with the shuttle can be planned and implemented in just a few hours. The space station requires nearly 30 hours to plan and execute moves because of the need to utilize the station’s Russian thrusters or to activate the propulsion systems on one of the docked spacecraft.

In 2009, we witnessed the first major collision between two intact satellites — a U.S. Iridium satellite and an aging Russian Cosmos. The collision created 2,000 extra chunks of metal space debris orbiting the Earth.

A 2011 report by the National Research Council warned that Earth orbit paths may be reaching a “tipping point” where collisions will become more common. The researchers suggest that the immediate, orbital space around Earth could be 10 to 20 years away from severe issues.

To find out more about space debris and its removal, continue here.

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