how to take out a satellite?

I was wondering how would the military take out enemy satellites? GPS guidance is out of the question. Would it be ground based radar to track it and send a missle? Just curious, I imagine it to be hard for a missle to manuever into position when reaching space to knock out a satellite that could be orbiting the earth at a fast speed. Also do satellites have counter measures? perhaps changing there orbital trajectory? and if so do incoming missles have the ability to change its trajectory in outer orbit as well given that there is no/little atomsphere to allow it to manuever?

There's the F-15 ASAT program. And more recently a laser test used an old USAF sattelite to see if they could hit it or not. Sorry, I forgot the name of the laser, but it's a new system.

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Originally posted by Mr.E
I was wondering how would the military take out enemy satellites? GPS guidance is out of the question. Would it be ground based radar to track it and send a missle? Just curious, I imagine it to be hard for a missle to manuever into position when reaching space to knock out a satellite that could be orbiting the earth at a fast speed. Also do satellites have counter measures? perhaps changing there orbital trajectory? and if so do incoming missles have the ability to change its trajectory in outer orbit as well given that there is no/little atomsphere to allow it to manuever?

Actually GPS should work just fine in space, if anything it will be more accurate without atmospheric distortions throwing off the signal. The military (NASA? Darpa?) tested GPS from "outside the constellation" and found it still worked.

The only system we've succesfully tested was a multi-stage missile fired by an F-15. Satellites can be tracked from the ground, and once you've got it's trajectory figured out you fire a missile into it's path. The warhead itself will need it's own tracking system (IR/Radar) to be accurate enough to hit using thrusters (there's no atmosphere to steer with). That's the general overview anyway; the execution is a bit trickier and neither the US nor Russia officialy deployed a reliable system.

The alternative is to set off a nuke, which will take out any satelitte within 1,000km of the detonation... this technique is a bit indiscriminate to be used, though, and is banned by treaties.

I doubt satellites carry any countermeasures. Getting stuff into space is expensive, measured in $1,000's per pound. Any countermeasures or evasive systems (and the sensors needed to properly employ them) would vastly increase the cost, weight, and complexity of a satellite. I doubt it would be worthwhile with no functional ASAT weapons currently deployed.

Wiki "Anti-satellite weapon" article: en.wikipedia.org...

Originally posted by Zaphod58
There's the F-15 ASAT program. And more recently a laser test used an old USAF sattelite to see if they could hit it or not. Sorry, I forgot the name of the laser, but it's a new system.

home.att.net...

The MIRACL was built in 1980 and has been doing so amny successful intercepts of target ssincet the 80's,hell the navy shot down a misisle in 1978 with a laser and made a baseline demonstrator in 1973.