Techniques for detection of high-altitude nuclear explosions

The Central Radio Propagation Laboratory (CRPL) is conducting a study for the Advanced Research Projects Agency (ARPA), Project VELA, of ground-based techniques for detecting geophysical effects produced by nuclear explosions at altitudes above about 20 km and in space. This activity has been designated HANDS, an abbreviation for High-Altitude Nuclear Detection Studies. A substantial amount of experimental data exists on effects produced by high-altitude explosions and theoretical predictions have been made of effects expected from explosions in space. The ability to record and identify these signatures is limited by a lack of knowledge of natural variations, especially those having fractional-second onset times. The objective of the HANDS is to develop methods for detecting nuclear explosion effects in the natural background. The experimental facility for collecting and processing background data from a collection of colocated geophysical sensors is described.