Tuesday, July 5, 2011
Our Orbital Junkyard
The expression “Out of sight – out of mind” is often used to rationalize why people are comfortable contributing massive amounts of trash to their local landfills. The issue of tossing out our junk is easily ignored, as the landfill is not in our backyard. If it were, the amount of junk tossed by the average person would decrease drastically.
A little farther from our local landfill, tons upon tons of waste that does not make it to a designated land disposal site eventually floats to an undesignated water-based one. Sadly, 20% of the Styrofoam that is produced finds its way into the ocean, where it slowly decomposes over hundreds of years. Unbelievably, square kilometres of the stuff are floating in certain locales of our hydrosphere. If this insult to our environment were floating in a lake in your neighbourhood, it would be hard to ignore. As it floats hundreds of miles away, it is out of mind.
It is not surprising then that man continues to fill yet another of its reservoirs with waste: our orbital environment. To quote the film Wall-E, “There’s plenty of space up in space!” Indeed, what could be a better place to store our junk? The space beyond our atmosphere is plentiful, and it is most certainly out of sight – unless of course you happen to be aboard the international space station, in which case even small space debris poses a life-threatening risk.
What is meant by space junk?
Most objects that orbit the Earth began on Earth. While hundreds of satellites are currently operational, thousands of them are decommissioned. Once satellites are no longer used, they are not physically brought down from orbit, as to do so is prohibitively expensive.
Beyond our atmosphere there is no drag force, no fluid to push up against. In a car, boat, train or plane, it is expensive to thrust forward, but free to press the brakes. In space, slowing down by 100 m/s is just as expensive as speeding up by 100 m/s. For this reason, satellites that are placed in orbit remain there indefinitely – all satellites are destined to be space junk eventually.
Why is space junk a problem?
Cluttering up the space around us makes navigating it a greater challenge. The first space missions that left the Earth’s atmosphere entered a nearly empty abyss. Today’s missions must contend with traffic.
On occasion, two satellites do actually strike one another. The resulting collision is more extraordinary than that of two airplanes, as the relative velocity of two satellites can be many kilometres per second. A collision of this type, though rare, is actually quite devastating to space traffic, as it transforms two large pieces of space junk that were easy to track into thousands of small pieces of space debris, some of which are not detectable. When one such collision occurs, it increases the likelihood of future collisions occurring, and we find ourselves on a divergent space junk curve. Also worrisome is the fact that a single piece of space debris just one centimetre in diameter could effectively destroy the International Space Station.
I think that logistics and safety are not the only reason why we should aim to keep the space around our planet clean. It just seems ethically wrong to make a mess outside of where you live. We evolved on this planet. As bad as it is to pollute our biosphere of land, water and air, it is, to a certain extent, worse to pollute space. I do not feel as though the Earth is ours to pollute, but I feel we have even less right to pollute the space that surrounds us.
Over the next decade, a mandate to prevent space cluttering will be implemented. It will soon become illegal to send a payload to space without a plan to return it to Earth once it is no longer in use. Such a law would increase the cost of satellite placement quite dramatically, but it is the responsible thing to do. Who works on such legislation? There are actually more space lawyers floating around out there than you might think.
It would be great if there were some super space vacuum cleaner that could just suck up all of the little pesky particles floating around out there. It’s kind of ironic that the one place that a vacuum cannot work is in a vacuum.
In all seriousness, cluttering up the volume of space around us with junk just adds an additional hurdle for us when it comes to utilizing and exploring space. The Earth’s gravitational pull is a worthy adversary –astronautical navigation is challenging enough without the burden of dodging projectiles.
I hope a responsible satellite decommissioning law comes into effect sooner than later. If not, the space surrounding our planet may one day begin to resemble that which surrounds Saturn.