Cog and Helix

Satellites Collide February 17, 2009

Two satellites collided in low Earth orbit last week, prompting worries about the likelihood of other space collisions as the number of orbiting satellites grows.
There are a lot of bits and pieces floating around up there, and they are all moving at incredible speeds. For example, a while ago the space shuttle suffered a half-inch crater in its windscreen from nothing more than a paint chip. This paint chip was travelling at more than twenty thousand miles an hour.
What worries me is this: The two satellites exploded into two clouds of debris that orbit the Earth, gradually becoming rings. Now it’s much more likely for another satellite to travel through one of those rings and be hit by shrapnel big enough and fast enough to destroy the satellite, leading to a new ring of debris and increasing the chances of collision even more. This is called a cascade effect, in which a single event can lead to an accelerating chain of other events, with huge consequences. Imagine dropping a single grain of sand on a sand dune. It hits two grains, they hit four grains, and on and on until you have a sizeable landslide. It’s that kind of thing. The more garbage you have up there, the harder it will be for satellites to avoid becoming clouds of garbage themselves. This could have severe consequences, considering how much of our communications technology relies on satellite relays. Let alone the risk for big guys like the Hubble Telescope or the International Space Station.
The New Scientist talks about it in this good article.

Finally fans of informed speculation should check out this website. It’s a collection of intellectuals and experts from various fields answering the question “What will change everything?”
Especially check out George Dyson’s article on interstellar viruses.

So long for now.