The USS Hopper successful test fired a interceptor missile (known as a SM-3 Block 1A missile) off the island of Kauai, Hawaii. The three stage missile shot down the test missile launched from the Pacific Missile Range Facility on Kauai. The intercept took place about 100 miles above the Pacific Ocean. This marked the 23rd such firing by ships equipped with the Aegis ballistic missile defense system. Last year, the intecptor missile even shot down a dead US spy satellite.
Another US Navy ship, the USS Lake Erie used another SM-3 Block 1B missile this time. The 1B features improved propulsion system and has a better signal processor. ANd the warhead seeker is better too.
This is in response to North Korea on July 4th violating the UN Security Council resolutions by launching seven ballistic missiles into waters off of North Korea's eastern coastline.
Ref. Daily Mail (UK) on July 31, 2009 article by their Foreign Service(http://www.dailymail.co.uk/news/worldnews/article-1203370/Pictured-U-S-missile-defence-test-hailed-success-North-Korea-tensions-rise.html).
Photo is a AP picture that was with the orignal article.