[qzxvwt]

Wow:

Total number of operating satellites: 1,381 (includes launches through 12/31/15)[1]

Wasn't aware that the +15,000 satellites (loosely defined) currently orbiting the Earth (according to SATCAT) are mostly junk...

But one other really interesting thing I found once in this data was that a huge percentage of all earth orbiting satellites are debris from China's Fengyun 1C sat, which they blew up into currently over 5000 pieces to test a missile [2]. I just think it's funny that China did this, and now we have to track every single piece indefinitely. :)

[1] http://www.ucsusa.org/nuclear-weapons/space-weapons/satellit... [2] https://en.wikipedia.org/wiki/Fengyun

[mikeash]

I don't think it's really indefinitely. Sun-synchronous orbits are usually 600-800km up, and atmospheric drag makes orbits at that altitude decay eventually. It'll probably take decades before it's gone, but it's not stuck up there forever.

Another big debris incident was the 2009 collision of an Iridium satellite and a dead Russian communications satellite:

https://en.wikipedia.org/wiki/2009_satellite_collision

When you think about the volumes involved, it's pretty amazingly bad luck that they managed to bump into each other. These were fairly low and the debris is deorbiting reasonably rapidly, so it's not as big of a deal.