deadly force
Steve,
Florida law only authorizes deadly force to prevent the commission of a "forcable felony", all of which are crimes against persons not property and are crimes of violence Ie rape, kidnapping, robbery, assault with a deadly weapon etc.
Federal law would apply to this circumstance, in addition to concurrent Florida law if there was a memo of understanding in place whereby the Feds authorized concurrent jurisdiction.
I worked in a federal facility once where top secret information was kept, about 20 years ago, that had a sign at the entrance which warned that "deadly force is authorized to prevent unauthorized entry of this facility" (paraphrased everything after "deadly force"). I don't know if that was a bluff or had a basis in federal law. The law regarding deadly force has changed since that time I believe.
My gut tells me that there is probably a federal law that would authorize deadly force against someone attempting to fly into the space shuttle, but I am not aware of a specific law on that point.