Space Shuttle Delay (fuel tanking Question)

A question came to me yesterday after the shuttle launch was delayed due to a errant sensor. When they Detank the fuel from the External tank after it has been loaded either for launch or one of their tanking test that they sometimes perform at the pad, what do they do with fuel? Can it be reused or is it just waste at that point? I heard a news report that the cost to scrub the launch was in the neighborhood of $500K in fuel and labor cost.

I cann’t see why they would not be able to reuse the fuel.

My second question is do they process the liquid Hydrogen and Liquid Oxygen on site or do they have to ship it in?

The save what they can. But, there is significant loss of cryogenic fuels due to heating from friction and heating in transfer lines etcetera.

I don’t know the answer to your second question.

They ship it in. Here is a fact sheet about NASA fuels (warning: it’s a PDF).