21 February, 2008
Good Shot! Go Navy!
Some good explainations from the BadAstronomy guy
But I doubt the US was concerned about technology getting to the ground. I think it really was about the hydrazine. I bet NRO has specs to ensure the classified aspects of their projects burn up properly on reentry. Like he says, these NRO projects reenter all the time, usually on command and into known places, but NRO isn't going to take the chance that a reentry will go wrong and plop a classified payload in China. So, I bet there was no concern, as was stated, that classified tech would be found.
The below video shows how the debris spreads. A misconception people have is that the missle shot the satellite. Actually it is more like the missle was run over by the satellite. The NRO satellite is traveling in orbit around the earth at 17000mph, the missle isn't going nearyly that fast. This is more like driving my Jetta onto the tracks just in front of a Japanese Bullet Train at full speed. The speed of the collision at 17000mph is what destroyed everything. The resulting debris continues on in mostly the same orbit the NRO satellite was traveling in, mostly unchanged. Now each piece is smaller and affected by the earth's atmosphere more than the whole was. Pieces have been slowed and thus dip lower into the atmosphere. Any fragments headed upward will be turned around by the earth's gravity and come back down, again dipping lower into the atmosphere and burning in. As the video shows, when the parts get low enough, they really start to slow down due to air friction and fall to the earth. But not all at once, it will take days for it all to come down.