BMEWS - 510 Full Days - J-Site

Because of the very low humidity and crystal clear air, it was impossible to accurately judge distance. Very early in my tour someone asked me how far I thought it was from J Site to the glacier across the fjord. I could tell it was quite a way off and guessed "maybe five miles." It turned out that the glacier was about seven miles away (recent Google Earth measurement)! When the weather warmed up enough for us to be outside for extended periods, but before the fjord thawed, we left J Site at the end of a shift and attempted to walk to that glacier. We turned back long before reaching it in order to get back to J Site for our next shift with a new respect for the vastness that was Greenland.

In apparent harmony with the rest of Greenland, J Site itself was immense! The site, housing a single radar system, was made up of nine buildings connected by an enclosed roadway, which we called "the tunnel", stretching for over a mile. There were four stationary detection radar antennae, each about the size of a football field arranged in an arc, facing generally north. In front of each antenna was a scanner building which housed the "organ pipe scanner" which provided the radar energy and scanning motion to the stationary antenna. Since the detection radar antennae were too large to move, the organ pipe scanner moved the beam with relation to the antenna. It got its name from the arrangement of several dozen waveguides or pipes, which were fed from a rotating waveguide switch. The pipes, each connected to a feed horn, formed two horizontal rows, one above the other. The beam from each antenna provided radar coverage of 40 degrees, yielding a total of 160 degrees of radar detection over the pole. The four fan-shaped beams of radar energy would provide a warning of every missile firing that took place in the Soviet Union. The job of BMEWS was to remove any surprise, assuring Soviet destruction if they launched an attack.

Between each of the four scanner buildings, about an eighth of a mile down the tunnel was a transmitter building. Running through the tunnel were literally miles of waveguide, connecting the scanners to the transmitters with several sources of energy each. Hundreds of miles of inch-thick, multi-conductor cable also ran down the tunnel in cable trays stretching between the buildings carrying control, communication and radar receiver information. My earliest impression of the installation lay with the precision with which the cables were placed. Each was laid perfectly straight in the cable tray, never crossing over or under another. Each was tied down at precise intervals, with the knots in the cable ties all facing the same direction. Where cables had to bend around corners, the radius of the bends of all the cables in the tray were exactly the same. A five-billion-dollar project (in 1960 dollars), the Air Force demanded, and got, perfection. At the end of the tunnel were the site mess hall, receiving docks, and a machine shop. Just beyond the mess hall and shop was a power building which provided backup electrical power in case of a main power failure. Providing transportation between the buildings was a passenger trolley made up of a warehouse tug and several warehouse trailers which had a bench seat built down the middle and enclosed against the cold. It made scheduled trips from one end of the tunnel to the other, stopping at each building to pick up and discharge passengers and small cargo. Not comfortable by any means, the trolley beat walking when it was cold.

When we first arrived at Thule, the only operational radar was the detection radar which went into service in September, 1960. The stationary detection radar system looked out over the North Pole for a first warning of missile attack, providing launch and trajectory information to the Missile Impact Prediction System (MIPS) computer. MIPS could provide a relatively coarse level of prediction of the missile's target based upon the detection radar returns. The detection radar delivered two fan-shaped energy patterns, one above and at a higher angle than the other. As a missile was launched, it would penetrate the lower beam. Signals returned from the missile would carry "doppler" information, which provided a measure of motion toward or away from the J Site, as well as range and azimuth information. A few moments later, the missile would penetrate the upper fan, providing a somewhat finer measure of trajectory. The difference in range between the first fan penetration and the second, combined with the doppler information and azimuth from each penetration, would provide sufficient information for the BMEWS MIPS computers to determine whether a missile was a potential attack threat.

Under construction was the tracking radar system which would be used to look at potential threats identified by the MIPS and the detection radar data and fine tune the prediction of the missile's probable target. The massive radome had just been started on the roof of transmitter building three. Soon to become a white sphere 110 feet in diameter at the equator, the geodesic dome was being lifted into place, piece by piece, by a crane which reached 150 feet into the sky and assembled by a crew hanging in a work basket in another, equally large, crane. The dome was constructed of a honeycomb material constructed of paper and epoxy resin in a honeycomb about 6 inches thick. There was a combination of several different shapes, pentagons, and hexagons, which were bolted together to build the dome. I delighted in watching the radome's progress as I arrived at J Site each day.

The construction of the tracking radar's antenna and mount was an engineering feat. The pedestal upon which the tracker's moving antenna would be mounted was built of solid, reinforced concrete in the shape of an hexagon eight feet on each face. This pedestal, buried in the permafrost down to a shale base about 30 feet below the surface of the ground, would extend upward to the roof of the transmitter building three stories above. In order to dissipate the heat of the curing concrete, which would melt the permafrost and cause the shale bedrock to slip, a refrigeration system was constructed around the underground portion of the pedestal. The refrigeration ensured that the permafrost stayed frozen and the antenna pedestal would remain stable. It always seemed to me to be paradoxical that one needed to refrigerate the permafrost!

J Site power was normally supplied by oil fired turbines aboard a ship at permanent anchor in the bay. About 85 megawatts would be required to provide full power to the radar and auxiliary equipment, lights and computers. Heat generated by the power ship kept the water in the ship's permanent mooring thawed even at -40 degrees. Providing backup power were six incredibly large diesel powered generators in the J Site power building. Each generator could supply 12 megawatts. The engines were four cylinder diesels of mammoth proportions; the cylinder bore measured about 4 feet in diameter, and connecting rod bearing journals were nearly 6 feet in diameter. Even with this much backup power, the few times we needed it we had to detune the transmitters to about 80 percent of the normal output power and turn off many of the lights just to keep some capability. Happily, it was rare that we needed the backup; the power ship was very reliable.