European Stars And Stripes (Newspaper) - May 24, 1986, Darmstadt, Hesse Page 16 the stars and stripes saturday May 24, 1986 wooden beams bound by 250,000 bolls of Wood and Iberg ass make up the 12-Ttory-High electromagnetic pulse simulator at Kirtland fab in new Mexico. Seeking ways to shield military electronics from mighty Emps by Matt Mygatt associated press microchips those sensitive computer age workhorses Lor everything from communications to defense were in their infancy the night starfish prime lit the sky. A rocket carried the nuclear device 280 Miles into the atmosphere Over tiny Johnston atoll in the Pacific Ocean about 925 Miles Southwest of Hawaii. The 1.4 megaton nuclear detonation on july 9, 1962, was one of the last of its kind before the United Stales agreed to ban above ground nuclear tests. It also was one of the last limes scientists had a Chance to study a full scale electromagnetic pulse triggered by a High Altitude atomic blast. The Emp surge drove detection meters Oil their Scales in Hawaii where strings of streetlights flicked out. Ever since that time people have been studying the effects of High Altitude Emps says Conrad Longmire. Who has been investigating the pulses since about 1960. It affects Telephone lines the . Power Grid . Military equipment in general. This problem seems worse than it was in 1962 because electronics these Days Are More the military is keenly interested in Emp effects. Key studies Are being conducted at Kirtland fab in Albuquerque n.m., where scientists Are trying to find ways to shield or Harden electronics from the mighty pulses. An Emp could be a Keystone in a wartime scenario. An enemy nuclear device could be triggered Over the . Heartland generating an Emp of perhaps 50,000 volts per meter which could hit sensitive electronics within line of sight. A blast at 250 Miles can be seen As far away As about 1,350 Miles says Longmire a former los Alamos National Laboratory researcher who now is chairman of the Board of Mission research corp. In Santa Barbara Calif. The total amount of Energy in an Emp itself is not very great Longmire says. Quite often however equipment fails because the Emp puts that equipment into the state in which its own internal Power produces the army it. Col. Richard m. Smith chief of the Emp effects division at the defense nuclear Agency in Washington d.c., said the need for shielding is much More critical today because the increased use of integrated electronics makes sensitive equipment More susceptible to Emps. Longmire says old electronic circuits based on vacuum tubes were much harder to damage than these Little transistor components that people have these scientists have a pretty Good handle on the makings of an Emp. Albert Griffin chief of the test operations Branch at the air Force weapons Laboratory at Kirtland says the main constituents of a High Altitude nuclear detonation Are a rays and Gamma rays. The High Energy radiation interacts with air molecules in the upper atmosphere and knocks off electrons from the molecules. The electrons called Compton recoil electrons Are knocked Forward like billiard balls and get trapped by the Earth s magnetic Field Longmire says. They tend to spiral in unison in a Given direction Griffin says. It s that flow of electrons which basically is a current which is the the Compton electrons radiate out like a wave from a radio transmitting Antenna Longmire says and that wave is the Emp. All this happens in a fraction of a microsecond. Very Short very intense. Anything Metal can pick up an Emp. When the pulse fails on wires such As a Delphone line it can induce currents in the wires in the order of thousands of amperes Longmire says. Unless the electrical systems have been designed to keep out such currents they can be damaged by it. Very Large scale integrated circuits Are exceedingly immunizing electronics against Emp is not impossible but it can be expensive he says. Smith said the skin of an air plane offers Good Protection against Emp but openings such As rivet joints windows and hatches must be sealed. A Small opening becomes a very Large opening electronically he said. But it s Tough to Seal those openings for permanent Protection. One thing we know quite Well is How to protect things Smith says. The difficulty is when the system needs Protection Over America s underground command centers Are completely sealed and scientists Are looking into hardening the nation s communications systems and its Power Grid against Emp. Satellite Points pose no Emp problem Smith says. Griffin says fiber optics which do not respond to Emp could be coupled Between subsystems doing away with solid wire connectors. The air Force weapons Laboratory operates five Emp simulators at Kirtland. One aptly named trestle looks like someone went wild with a giant wooden erector set. Trestle is 12 stories of Douglas fir and Larch girders bound together by 250,000 wooden and fibreglass bolts. More than 6 million Board feet of lumber was used enough to build 4,000 Frame houses. The air Force says it is the largest glued laminated wooden Structure in the world. Trestle which Cost about $58 million enables scientists and engineers to simulate in Llight Emp effects on aircraft electrical equipment. It mimics an Emp by using two 5 million Volt pulses that discharge into a wire Antenna mesh surrounding an air plane which rests on a 200-foot-Square laminated Wood 118 feel above ground. Planes can Fly into Albuquerque International Airport and taxi directly to the via a 400-foot-Lona 50-loot-wide ramp. Trestle can handle an aircraft the size of a c-5 Galaxy which weighs at least 550,000 pounds the first tests involved a b-52 in March 1980. Special electrical sensors measure aircraft Emp response signals from the air plane and fiber optic cables transmit them to computers inside a shielded enclosure for recording and analysis. Smith said pulse Levels can be mathematically extrapolated to higher voltage Levels and researchers can come up with approximations of performance " we do not have All the answers yet Griffin says ways in overcomin9 Thal
