Excellent research, now donate it to the San Diego Air and Space Museum for all to enjoy.

I think they should keep it running until it dies. It would take a very long time for a few little tugs to clean up LEO.

I agree with Mark A, it should go to a musuem where others can see how cool it is and how it is the first step into the future.

Nah, LEO would be a good use for it. But mining an asteroid might be better. setting up a space station in the asteroids to mine several of them might even be better. i wouldn't want that duty.

Just wondering how fast a probe with 5,000lb of xenon fuel it would be moving after 10 years under thrust?

I want one to replace the ICE in my Prius.

To check the force that would propel your Prius with this ion thruster, get a standard issue 100 gram chocolate bar (go for the dark 85% cocoa!) and eat three-quarters.
Then, take the rest and put it on your flat hand. The force you need to hold that piece of chocolate is about equal to the thrust from this engine.
But no worries - remember people pointing out how much stronger horses are when they saw the first motor cars? Things take time...

@Bill Cumming This doesn't exactly answer your question, but I calculate that a 5,000lb spacecraft putting out 1lb of thrust would be going about around 1.3 million mph after 10 years.

Interesting article. I was wondering what the velocity and/or temperature of the exhaust is? Is there any chance at all that the ion thruster technology will ever be able to accelerate protons to a high enough energy so the p+Boron fusion reaction can be made to happen? For the uninformed this is a clean nuclear reaction producing no nasty radioactive byproducts.

I don't think it's ever going to go faster than the exhaust of 90,000 mph.