Bad weather twice postponed the intercept test scheduled for the Ground-based Midcourse Defense program, previously known as National Missile Defense. Weather plays a much greater role than most realize in the success of these demonstrations. Rain, for example, could thwart the radar from seeing the target.

The official reason for cancellation is that the poor weather at Vandenburg Air Force Base "did not meet range safety requirements." High winds at the test site may have been enough to force a postponement, but less than ideal weather could mean that the interceptors cannot intercept at all. According to a July 2000 internal study prepared by then- Director of Operational Test and Evaluation Philip Coyle, weather conditions could drastically alter the effectiveness of the missile defense system. "Radar discrimination, IFICS [In-Flight Interceptor Communications System] transmission/ reception, and DSP/SBIRS [Defense Support Program/Space Based Infrared System] launch detection may be operating at their technical limits, and heavy rain or dense cloud conditions may have significant effects on their performance." Coyle, in fact, listed the testing of the effects of weather on radar, telemetry and satellite operations as part of his recommendations for ensuring a more accurate and realistic testing program for the missile defense system.

Pentagon officials and missile defense proponents are likely to argue that this weekend’s brief postponements are only evidence of appropriate due caution in the testing program and that the Ballistic Missile Defense Organization is taking great care to ensure that the test provides a clear readout of where the program stands. Throwing extra variables and conditions into the test, they will argue, would not be scientifically sound because it would alter the test parameters and perhaps lead to an inconclusive result. Such an argument carries a certain amount of credence. At the same time, however, the failure to test in these conditions is an admission of a weakness in the system. This would not matter if the system were simply likely to remain in the testing and developmental stage for the near future. However , some in the administration are pushing for the early deployment of a minimal, yet still operational missile defense capability in Alaska by the end of the president's first term.

Deploying an ineffective missile defense system helps no one. Deploying a system that is at best still five or more years from true operational tests under a variety of conditions and at worst may have a known and acknowledged weakness is downright dangerous. Testing in ideal weather, of course, is not the only artificiality to the tests. A recent report from the Union of Concerned Scientists revealed for the first time that the transponder on the target guides the interceptor to within 400 meters of the target, bringing the interceptor far closer to the target that the target is to any decoys. Without the transponder, it may be impossible for the interceptor to locate the target. All the interceptor test have taken place under the same weather conditions, same time of day, same target trajectories, same speed, and all with beacons on board the targets.

A missile attack on the United States is not likely to arrive on "our" terms. Before it deploys a missile defense system, the Pentagon and BMDO should ensure that it has been thoroughly tested in all conditions, good weather and otherwise. People have long recognized it would truly be a dark day if the U.S. were to be attacked by a nuclear-armed missile, and the Ground-based Midcourse Defense program is supposed to provide our last line of defense. The U.S. must now be careful that we don't generate a false sense of security by deploying an untested system too early, and guarantee that such a day would not only be dark, but rainy as well.


Click here to view the Coyle Report (pdf).

Click here to view the Union of Concerned Scientists working paper regarding the use of radar transponders and the hit-to-kill system (pdf).