A couple of weeks ago, I blogged about a new NASA video showing the relative locations and orbits of the space debris they are tracking. The assumption here is (and I think it’s correct) is that all this space debris is man-made. Anything natural approaching from the cosmos is either going to hit the atmosphere or just speed on by as it is traveling much too fast to be captured by earth’s gravity.
And there IS stuff that comes by earth from ‘out beyond’ and it happens more often than you might think. NASA has just released a map of all small meteorites (from 1 meter to 20 meters in diameter) that have impacted the earth’s atmosphere from 1994 through 2013 – a period of 20 years (once again I am indebted to the most excellent SpaceRef newsletter for this story). In that 20 year period, NASA traced 556 meteorites of this size impacting the earth’s atmosphere, about one every 13 days. I think that’s much more frequent than most people imagine.
Any one of these meteorites would be capable of damaging or destroying a space elevator and, like space debris, will have to be carefully watched and tracked. But unlike space debris, where you have areas along the length of the space elevator with much higher (and lower) probabilities of impacts, meteorites like these could literally hit the space elevator anywhere along it’s length.
A Space Elevator Operations Center will have tracking objects like these as one of its primary responsibilities.