Rumor has it that the administration’s Missile Defense Review (MDR) may finally be released this week. As policy makers discuss its recommendations and consider expanding US missile defenses in various ways, they should have a realistic view of the capability of these systems—and their limitations.
There have been 18 intercept flight tests of the Ground-based Missile Defense (GMD) system through 2018. Contrary to some claims, these tests have not demonstrated that the missile defense system would be successful in intercepting incoming warheads under realistic conditions.
The primary purpose of the tests has been to demonstrate “hit to kill,” that is, to test the ability of the missile defense kill vehicle to home on the target warhead and physically collide with it. Yet the system has succeeded in doing this in only half the tests overall, and only 40 percent of the latest 10 tests, so the record is not improving.
Moreover, none of these tests have included realistic decoys and other countermeasures that the system would be expected to face in a real attack—including an attack from North Korea. So the effectiveness of the defense against a real-world attack would be even lower than the 40 to 50 percent seen in the tests.
Some of the 18 intercept tests have included decoy balloons to test whether the kill vehicles can distinguish the mock warhead from other objects. However:
- The decoy balloons and other objects used in the tests have been designed to look very different than the warhead, so have been easy to distinguish;
- Information about the different appearance of the objects is given to the kill vehicle in advance, so that it can recognize which object is which;
- Decoys that prove difficult for the kill vehicle to distinguish have not been used in subsequent tests.
What this makes clear is that the GMD tests have not demonstrated the ability of the GMD system to successfully discriminate objects the kill vehicle might see in a real-world attack.