Space Debris Threatens Deep Space Missions

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Gravity sucks...

No.  Not the movie.

Despite it's shortcomings, Gravity was actually pretty entertaining.​

We're talking about real gravity... the kind that keeps your feet firmly on Earth and causes apples to fall on your head.  

And the kind that keeps satellites in orbit.

You see, there's a big problem in Earth's orbit. You've surely heard about it and seen images of it. It was even made famous by the movie Gravity.​  Yep - it's...

Space debris​

There are currently 1,305 active satellites up in orbit, with thousands more that are inactive. There are also quite a few other objects like spent rockets from previous missions, including one that could put on a pretty spectacular show mid-November 2015.

Active Satellites. Credit: Union of Concerned Scientists

Satellite Quick Facts. Credit: Union of Concerned Scientists

The problem is that, every once in a while, one of these satellites explodes or two of them collide.  And when they do, they create a ton of tiny fragments called space debris.

And the problem is growing.

The number of objects in space has risen quickly over recent decades, as a GIF made by the ESA shows ( the size of the objects has been greatly exaggerated relative to the Earth’s size):

space debris animation

Credit: ESA

The majority of satellites and debris are grouped  in Low earth Orbit (LEO), and the outer ring of objects is what’s located in Geosynchronous orbit (GEO).  

Currently, there are about 17,000 objects in orbit that are being tracked, with only 7% or so that are active satellites.  But -- here's the problem --

only the larger pieces of space debris are actually being tracked.

the largest pieces of space debris orbiting Earth

The largest pieces of space debris orbiting Earth

 Take a look at this image.The amount of orbital debris is astounding - but it doesn't even include the smaller pieces of space debris.  The pieces that may only be as big as 10 cm or so.

Estimates for the number of these smaller objects range from 150,000 to 500,000, and there are over a million total pieces of debris larger than 2 mm, as explained in this video by the ESA.

The issue is that at the incredible speeds at which space objects move (most LEO objects zip along at over 17,000 mph), a collision with even a tiny object can cause devastating damage to an active satellite or spacecraft. 

Just like in the movie Gravity.

But here's a little known fact...

Over a third of all space debris originated from just two events:

  • China’s 2007 anti-satellite test, when China intentionally blew up one of its own satellites, creating 3,000 new pieces of debris large enough to be trackable, and
  • a 2009 collision between two satellites that exploded into 2,000 debris chunks.

Each collision increases the amount of debris, which in turn causes more collisions and more debris -- a domino effect which scientists call the Kessler Syndrome.

​As we expand the human presence into space and on to Mars, the problem will get worse and will threaten the safety of any orbital outposts or refueling stations we need on our journey to Mars.

But here's the good news...

The problem of space debris is getting more and more attention. A number of groups are looking at ways to mitigate the amount of debris in LEO. Harpoons, lasers, even clouds of gas that can slow the debris down and cause it to burn up in the atmosphere are all being discussed.

But -- so far -- nothing has been put into to action and the amount of space debris continues to grow, threatening any plans of creating a large human presence in space.

What do you think?  What can be done to offset the growth of orbital space debris?​ Share your thoughts in the comments below .

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