HUNTSVILLE, AL -- The Army last week executed a live-fire test of the Patriot air defense system -- pitting a developmental PAC-3 software upgrade to address more advanced threats -- against a medium-range ballistic missile target at a test site in the Western Pacific. The March 23 event at Kwajalein Atoll in the Marshall Islands -- where the U.S. government has a missile defense test range -- was the first in a series of flight tests to validate software updates...