That, of course, is an underestimate, because in reality you’d need to use extra fuel to break out of Earth’s orbit before you could consider changing the orbit around the Sun. Probably at least another 1-2 km/s of delta-V.

Is that a lot? Well, consider that (according to the Wikipedia page on graveyard orbits; see ackpht’s post for the link), geosynchronous orbit satellites typically do not have nearly enough fuel for a proper de-orbit into Earth’s atmosphere, which would require about 1.5 km/s of delta-V; shifting the satellite to a graveyard orbit only takes about 10 m/s (0.01 km/s) of delta-V. This already tells you that sending satellites into the Sun takes far more fuel than geostationary satellites have available. Another way to look at it: station-keeping requirements for geostationary orbits are about 50 m/s (0.05 km/s) of delta-V each year. So to dispose of a geostationary satellite by sending it into the Sun would take something like 600 years’ worth of station-keeping fuel.

The answer has already been given, but you seem reluctant to accept it: fuel. It takes only a little to decay an orbit, but significantly more to send it “to the sun”.

Once I’ve recycled all the parked satellites,  I then can threaten all the cable TV sats. Put real history on the History Channel, make Discovery almost all science again, put the original “L” back in TLC, or lose your satellites..

Personally, I always wondered why they never tried to re-purpose the shuttle’s external tanks.  There were concept drawings that string several tanks together to form a toroid station.

The US military sees an ongoing and increasing need for a presence in space, and while they do have a huge budget, it’s still a budget. A vampire-sat system could cut costs by reducing the amount of fresh hardware that has to be lofted to keep a satellite functional. They are also no doubt anticipating scenarios where satellites suffer battle damage and need repair.

The biggest problem here is that as yet satellites aren’t designed to be dismantled- in orbit or anywhere else. Part of a vampire-sat program would be to develop vampire-friendly protocols for satellite design and construction.

DARPA wants to be able to argue for the safety of nuclear-based fuels in space. Nothing more.

Geosynchronous satellites are placed in a higher orbit to get them out of the way, but just a very slightly higher orbit that requires a very small delta-v: http://en.wikipedia.org/wiki/Graveyard_orbit. If the satellite cannot be moved to a junk orbit (and it happens), it can potentially interfere with active satellites. But all of them are staying in orbit close to the original altitude because leaving them there is the cheapest thing to do.

Not a rocket scientist, but I read a lot of stuff. A satellite in Low-Earth Orbit (LEO) travels at about 7.8 km/s. It takes quite a bit of fuel to get something up to that speed. Escape velocity from Earth is a bit over 11 km/s. So to get a satellite out of Earth’s gravity well, you’d have to make it go about 45-50% faster than it already was. They don’t carry enough fuel for that.

Slowing a satellite down enough to let it smack into Earth instead is a lot easier. Point the engine in the direction you’re headed, fire your remaining fuel, satellite slows down and eventually hits the atmosphere. That slows it down even more. Hell, if something goes wrong with a satellite in LEO and you run out of fuel, you can just wait. It’ll slow down anyway because the atmosphere expands and contracts enough that LEO satellites scrape it.

Whaddaya think, Cory? Got a rocket scientist stashed around here someplace to answer this?

You need a powerful engine and enough fuel to achieve escape velocity and leave earth orbit. Then you’d have to decelerate pretty violently collapse your orbit around the sun.

It’s incredibly more easy to just decelerate enough that the satellite can burn up upon reentry.

And many satellites don’t have engines strong enough to do even that.

Agree with Chuck; description is not consistent with video.