THE BURNED OVER DISTRICT

The components, called alternate divert thrusters, are vital to the high-precision guidance required to intercept and destroy an enemy warhead traveling at supersonic speed – a feat likened to hitting one speeding bullet with another.

The interceptors, deployed in underground silos at Vandenberg Air Force Base in Santa Barbara County and at Ft. Greely, Alaska, are the backbone of the Ground-based Midcourse Defense system (GMD) – the nation’s main defense against a sneak attack by North Korea or Iran.

The interceptors are multi-stage rockets, each with a 5-foot-long “kill vehicle” at its tip. The 150-pound kill vehicle is designed to separate from its rocket in space, fly independently at 4 miles per second and crash into an enemy warhead, destroying it.

The performance of the divert thrusters, which are supposed to keep the kill vehicles on course during their final approach to their targets, has been a source of concern for several years. In response, the Missile Defense Agency oversaw development of a new and supposedly better version, the alternate divert thruster.

An outside panel of experts privately advised the agency to put the alternate divert thrusters through “hot fire” testing, in which they would be revved up on the ground to see whether they burned smoothly and delivered adequate propulsion.

But in order to stay on schedule for a planned expansion of the GMD system, none of the 40 thrusters that are being installed on 10 new interceptors will undergo hot-fire testing, government officials told the Los Angeles Times.

Forgoing the tests “increases the risk for reliability issues going undetected,” according to a newly released report by the U.S. Government Accountability Office. The report says that such testing “verifies proper performance and workmanship.”

// posted by montag @ 2:10 PM