The May 30 test used the latest configuration of the Ground Based Interceptor, the U.S. military’s weapon for destroying incoming ballistic missiles. By the end of the year, the Pentagon plans to have a total of 44 GBIs deployed: 40 at Fort Greeley, Alaska, and four at Vandenberg Air Force Base, 100 miles north of Los Angeles.

The American launch followed a welter of North Korean missile tests, including a May 14 launch of a missile that left and reentered Earth’s atmosphere.

For Tuesday’s test, Syring said, a faux ICBM of the sort that North Korea or Iran might eventually deploy was launched from Kwajalein Atoll in the Pacific Ocean. The launch plume was detected by infrared sensors, Lockheed Martin’s Space Based Infrared System, orbiting in geosynchronous orbit some 22,000 miles up. The missile was then tracked by a variety of radar, including the Sea-based X-band radar (SBX) as well as land-based TPY-2 radars from Raytheon.

Syring said that if North Korea really launched a missile, the U.S. could actually bring more sensors to bear, including two TYP-2 radars in Japan and a long-range radar at Clear Air Force Station in Alaska.

“We test in the eastern two-thirds of the Pacific, where we don’t have the the Japan radar coverage that we would use against North Korea for detection. The radar that we used was a TYP-2 on Wake Island and then the SPX to replicate and facilitate the operation of the test,” he said.

Syring said the mock ICBM deployed decoys and other countermeasures that aim to trick the interceptor into missing the missile, but he declined to discuss them in detail.

Nor would he disclose the specific range of the test, citing classification. But he said the mock ICBM covered thousands of miles before the interceptor slammed into it northeast of Hawaii.

The $244 million test posed considerable logistical challenges. It’s a lot cheaper for North Korea to conduct missile tests than it is for the United States to conduct real-world missile defense exercises.

“We’re launching an interceptor that is flying thousands of miles past Hawaii and that requires us to shut down large parts of the ocean in terms of mariners, ship traffic, and air traffic. It’s infeasible to do it any other way,” Syring said.

Data from the tests will go into the development of the next generation of kill vehicles.

“The new development that we have going with the redesigned kill vehicle, which is ongoing, which we’ll flight test by end of calendar year ’19, will be the next step to not only improving reliability, but improving performance against the evolving threat,” Syring said.

MDA does not go into great detail about how that threat is expected to evolve, but recent budget decisions give a hint. The agency announced last week that they were seeking $259 million to accelerate the development of a multi-object kill vehicle, or MOKV, by some five years. The MOKV is basically a warhead that can knock down multiple incoming warheads at once, whether those are decoys or the real thing.

“We’re targeting the 2025 time frame for that,” Syring said.

As for the Ground-Based Midcourse Defense — the overall anti-missile system of which the GBIs are a part — the agency plans a fall 2018 test that will pit two interceptors against a single target. Why? “We shoot more than one in an operational real-world scenario,” Syring said. “We want to exercise the GMD system to gather data for what a first interceptor would do in terms of kill and what a second interceptor would see.”

And about five years later, around 2023, MDA will test its system against multiple inbound missiles.

“We’re in a very good step-wise progression here of not only increasing reliability, but being ahead of where we believe the threat will go in terms of complexity, countermeasures and ultimately consideration for capacity down the road,” Syring said.