Transcript for US successfully intercepts ICBM in historic test

Now to new images of a first of its kind missile intercept test. The U.S. Successfully stopping a mock long-range missile in space. That comes amid mounting fears North Korea will perfect a nuclear missile that can reach the continental U.S. Martha Raddatz has all the latest on that. Good morning to you, Martha. Reporter: Good morning, Amy. There have been shorter range test missile intercepts over the years but many of those failed, but this long-range test, they nailed it on the first try. It was the first live fire intercept test of an INT intercontinental ballistic missile in history, a critical victory for the U.S. Coming at a kit "Time warp." The mock warhead fired from an island in the pacific. More than 4,000 miles away at Vandenberg air base in California, the interceptor, or kill vehicle roaring into space from an underground silo to stop the mock missile and within an hour, the five-foot-long interscepter hitting its mark. It is a remarkable achievement, the equivalent of hitting a speeding bullet traveling 4 miles a second with another speeding bullet. This is a very difficult calculation where you have to look at its arc and figure out where the intercept is going to occur somewhere deep in outer space. That is truly rocket science in every sense of the word. Reporter: The test carried out after North Korea successfully launched its ninth missile this year, a short-range ballistic missile with Kim Jong-un watching. State run media claiming it was more precise than ever before. But this successful intercept sends a powerful message to North Korea. The head of the U.S. Missile defense agency saying the test demonstrates a capable, credible deterrent against a very real threat, Amy. Martha, while it's stunning and incredible to witness, it's important to note that this test was done under ideal conditions and was well planned. Reporter: It was. You do have to keep that in mind. Thankfully this has never had to be used in a real-life situation where an intercept would be much more challenging, Amy. All right, Martha Raddatz, we appreciate that. Michael. Thank you, Amy.

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