Tall King C radar, Soviet Union.
When the OXCART project was nearing completion, it was necessary to map out all SAM systems to prevent the craft’s shootdown.
“Scientists determined that Tall King radar signals, traveling in a straight line, would eventually collide with the moon at least part of the day. The trick would be to catch the signals as they bounced back to earth. To acomplish this, a complex “catcher’s mitt” was built. Near Moorestown, New Jersey, a giant sixty-foot satellite dish was aimed at the lunar surface. (…) Over time, as the earth and moon revolved and rotated, all of the Tall King radars eventually came within view and were charted.” (via)
