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Show since its introduction in World War 2 as chaff. Since the size of chaff is directly related to the radar wavelength, the longer the wavelength the longer must be the chaff. Carrying and deploying large quantities of six or seven-foot-long metal strips from a missile or decoy in ballistic flight add weight and complexity to the task. The Air Force's Rome Air Development Center has LTV Electrosystems' Continental Electronics at work building a multi-million-dollar VHP radar as part of the Advanced Ballistic Re-Entry Systems (ABRES) program. With it, Air Force presumably hopes to learn more about effectively countering such a threat. Vexing Challenge The continuous updating of a potential enemy's radar threat is one of the most vexing challenges for designers of penetration aids. It has thus far confounded still-undampened U.S. hopes of effectively using electronic counter-measures (ECM) techniques against enemy radar defenses. Some time ago, Air Force flight tested with partial success an active ECM technique developed by Sperry Gyroscope Co. Using this technique, ECM noise jammers intended to confuse enemy radars with their minute-long high-power bursts of noise are deployed in precursor decoys from a reentry vehicle. Once the knotty problem of supplying high power for available weight and volume was solved and tubes generating the high CW power in the radar band of interest were found, the estimate of the radar threat changed. Furthermore, the 1,500-mi.-range Russian frequency radar, code named Dog-house, could track these decoys for at least 1,000 mi. before their little jammers turned on. In the face of an ever-more ominous defense environment, a missile warhead today faces a tougher battle for survival than in the past, informed observers point out. And, survival will be more difficult tomorrow. In this climate, the inclination to adopt a saturation, or "barrage," type of missile re-entry system scheme for assured penetration appears to be gaining greater favor. Many warheads carried on board a single missile carrier statistically increase the chances of penetrating into and striking target areas by overloading or saturating the defense. This approach appeared to be evolving for the Air Force's latest re-entry system, the Mk. 18, which has temporarily been shelved because of budgetary squeezes. In this concept, the Mk. 18 system would carry many small, probably unguided, warheads for sequential ejection from the guided re-entry system during the time of maximum threat. These would descend onto a large "footprint" area. Four-stage Atlantic Research Athena rockets fired from a site at Green River, Utah, over the inland range into the White Sands, N.M., Missile Range carry subscale models of ballistic missile re-entry vehicles and penetration aids for test. Such a concept is an outgrowth of earlier studies by Avco Corp. and the General Electric Co., USAF's primary re-entry vehicle sources, in the CRESS program (Combined Re-entry Effort in Small Systems), which also was sponsored by the Atomic Energy Commission. This program was aimed at coordinating ballistic missile re-entry vehicle and warhead activities in an effort to optimize the design of missile re-entry systems, including the warheads themselves-and particularly to get better use of space in the system (AW&ST Mar. 8, 1965, p. 13). The "barrage" concept also is a logical step beyond the development of the General Electric Mk. 12 re-entry system for the Boeing Minuteman 2, the first operational ICBM system to have multiple warheads. For the past six years, the U.S. has been spending what is believed to be in excess of $200 million a year on penetration techniques. Through its ABRES program, which is administered for the Defense Dept. by the Air Force, actively aided by the Army and Navy, the Pentagon has spent more than $100 million a year since 1962, or a total of about $0.75 billion over a six-year period. Another $250 million has been budgeted for Fiscal 1968 and 1969, although budgetary cuts may curtail this. Much of the money, of course, is spent on boosters, range fees and other items needed to support penetration-aids development but not directly related to the development itself. On the opposite side of the ledger are surprisingly large quantities of money spent by weapon systems offices on operational re-entry systems, more accurate guidance concepts and the pur- Aviation Week & Space Technology, October 23, 1967 95 |