2011: A Space Junkyard

Space is a vast and empty void, right? Like the earth itself, it is so outrageously immense that we could never possibly affect it in any material way, right? Well, we've already managed to fill it full of junk after only sixty years.

Yes, there is so much junk in space now that astronauts on the space station recently had to take shelter when a piece of debris came within 1,000 or so feet. And this isn't an isolated incident. They had to do this in 2009 as well. Also in 2009 Iridium 33, one of the Iridium Constellation satellites, collided with Kosmos 2251, a defunct Russian satellite. (Iridium is a planet-wide network of 66 satellites in polar orbits used for satellite phones and pagers.)

What is all this junk? Some of it is old satellites, like Kosmos 2251. The Russians were notorious for launching lots of satellites with extremely short lifetimes, and they rarely bothered to deorbit them, something which NASA usually does to avoid this problem. Some of the junk is stuff that was dropped off manned spacecraft. Some of it is from intentionally destroyed satellites -- like the one the Chinese killed with an anti-satellite weapon in 2007.

But half the junk is debris from accidents like the Iridium-Kosmos collision. Which means that in the near term (10-20 years) the problem is going to get worse. Each time there's another collision there'll be that more much junk created, creating a cascade effect of more and more debris, causing more and more collisions.

Why is this stuff so dangerous? Orbital velocity in LEO (low-earth orbit) is about 17,000 miles an hour. A lot of satellites orbit in the same direction, a more-or-less equatorial orbit. But some satellites -- like Iridium and American spy satellites -- are in polar orbits so that they can, over time, communicate with or spy on any point on earth. When a polar satellite hits an equatorial satellite the amount of kinetic energy is huge. When the debris from that collision hits something else, it's still going 17,000 mph, and even a small bolt going that fast can totally destroy a satellite or the solar panels that power it.

In the long run the very thin atmosphere in LEO will eventually bring down most of the debris, as it brought down Skylab in 1979 (controllers changed the orientation to aim it, but it didn't land exactly where they wanted it to). But we'll probably have to take some action before then, as we put more and more things into orbit.

Many satellites have thrusters to correct their orbits (remember Jack Bauer always asking Chloe to reposition spy satellites for him?). Those thrusters could be used to deorbit the satellites. The problem is that their fuel is finite: the choice is between using the fuel for a longer useful lifetime for the satellite or for sending it to a fiery death in the atmosphere to eliminate the chance of collision.

The thing about this "pollution" in space is that it doesn't really hurt space or the planet earth at all. But it can hurt us. If our weather satellites are taken out by random junk, our ability to track hurricanes can be severely degraded, and people could die because they didn't get sufficient warning.

In a way, space junk is like global warming: the seemingly small increase of CO2 in the atmosphere from burning fossil fuels poses no direct threat to the planet, and it won't even kill all humankind. Directly. But it will cause the temperature to rise several degrees, which will cause polar ice to melt, which will cause the seas to rise several feet. That's a trivial increase in sea level in the grand scheme of things, but it so happens that most of our major cities will be flooded. It will disrupt billions of lives, and cost trillions of dollars as we have to either move or protect major cities with dikes as they do in the Netherlands. And that's not even considering the disruptions temperature changes will wreak on farming, water supplies and the lives lost in wars caused by those disruptions.

There always consequences when we throw things away, whether it's old car batteries and computers in the landfill, junker satellites in orbit, antibiotics and birth control pills down the toilet, the exhaust from our cars or the smoke and ash from our coal-fired power plants.

We used to think we could just throw crap away and never see it again. But now there are so many of us, and we create so much trash, that all our waste products eventually just come back around and hit us upside the head like one of those satellites.