You forgot to say the space shuttle will have to sit on the ocean floor for four hundred years...and then you come along and package the junk up for sale on e-bay. Under those conditions I think it should not be a big deal for anyone to complain about you doing some salvage and I doubt anybody would want to buy the shuttle junk...excect maybe one of your descendents.
You obviously know nothing about salvage law. Spain was not actively trying to salvage the wreck, nor did they know the location. This makes it fair game. Finder keepers. Mel Fisher went all the way to the supreme court with his Atoch case... and won. So will Odyssey as the Mel Fisher case set the precedent.
If the shuttle crashed, the military, NASA, and other government agencies would know where it is and they would be actively trying to salvage it. Odyssey could have no claims on a shuttle crash. The only thing they could do is get hired on as a subcontractor to assist the recovery. They would be paid for their service, and no they could not keep any of the finds.