The AICBM Panel of the President's Science Advisory Committee has had two meetings since submitting the last report dated May 21, 1959. On September 21 and 22, 1959, we met at Bell Telephone Laboratories, Whippany, New Jersey, to examine in some detail the status of the Nike-Zeus program. Following this, we met in Washington to further consider the Nike-Zeus program and, in addition, to review the overall AICBM effort. During the latter meeting we heard the following presentations:

The Role of Nike-Zeus in Defense of the Continental United States {U. S. Army)
Potential Contribution of Nike-Zeus to Defense of the United States (WSEG)

Budgetary Consideration of the Nike-Zeus Program (OSD-Air Defense)
The Advanced Research Projects Agency Ballistic Missile Defense Program (ARPA)



Decoy Discrimination

It is apparent that, in spite of the study efforts of the past year, no adequate decoy discrimination technique has yet evolved. We therefore cannot expect the Nike-Zeus system to be capable of satisfactorily distinguishing between incoming sophisticated decoys and true warheads,

Dr, Arthur Kantrowitz, whose group has been engaged in the design of decoys for the U. S, missile program, is convinced that it is possible to make decoys that are, by any known radar technique, indistinguishable from a true nose cone above an altitude of 170,000 feet or possibly even lower. Such decoys need weigh only about 2 to 4 per cent of the weight of the actual nose cone they are designed to simulate. Less sophisticated decoys have also been proposed and many of these (of even lesser weight) may, at altitudes greater than about 170,000 feet, be indistinguishable from true nose cones by any practical decoy discrimination technique. At present it is not even clear how tank fragments (that can be employed by the hundreds at almost no cost to the attacker) can be differentiated from true nose cones at sufficiently high altitudes. It is not yet known if this discrimination could be accomplished by evaluation of the radar signatures or whether it would be necessary to continually follow many tank fragments by radar. In the latter case, even a single nose cone accompanied by a large number of tank fragments could overtax the capability of the presently planned decoy discrimination radar. (One frequently mentioned possibility would involve the explosion of a "precursor" AICBM nuclear warhead at a very high altitude. It has been estimated that many of the tank fragments might be distinguished from a heavy warhead from radar observation of their resulting, relatively large, velocity changes. Analysis of this possibility indicates that it does not appear to be a reasonable procedure. This is especially true when it is realized that the precursor burst will produce a temporary radar blackout.)