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Raytheon has announced plans for a growth version of the Sea Sparrow missile that would be slightly longer than the current missile, with a new motor and the current Sea Sparrow semi-active seeker. Ray-
,. representatives suggest that it would be more attractive than a j^'P-launched version of the Hughes actively guided AMRAAM because e semi-actively guided missile would be far less expensive. s Parrow also figures in a proposed RCA small ship air defense ^tem—a kind of mini-Aegis. Presumably, this missile would incorpo- l>ate a remote-programmable autopilot, like that of the Standard SM-2 'red by Aegis ships. However, four could fit in each cell ol a standard ■ ark-41 vertical launcher. A ship could be armed with a combination of ' n8-range SM-2s and shorter-range advanced Sea Sparrows, giving it shots against short-range attackers, be mini-Aegis has been proposed for the projected NATO frigate.
Two-line Array Contract Awarded
Ij ®°uld announced in April that it was awarded a contract to design, (Rm ant^t6St a reconf>gurat>le multiline towed-array evaluation system ,i: ™*ES). Existing towed arrays are limited in gain because they are one-
dimi
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Sea Sparrow Coming
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fteon
ensional—their beams conical. To deal with quieter submarines, y must increase gain, and the only available method is to lengthen the /ray 'tself. However, it is difficult to keep a very long linear array from ^"txing as it is towed. Such distortion in turn confuses the beam-former SjSs°ciated with the array. Adding parallel arrays should increase gain ^ Snificantly because beams can be formed in two dimensions rather than e- However, there has always been some question as to how easily a U bhne array can be handled at sea; hence the need for a test system—
WleRMES.
manufactures the SQR-19 towed array sonar.
S. Navy Seeks AAAM
Jhe U. S. Navy has issued a Request for Proposals (RFP) lor proto- pPes of an advanced air-to-air missile (AAAM) to replace the AIM-54 (. °enix in the late 1990s. Unlike the Phoenix, which requires the sophis- Cated fire control system of the F-14 Tomcat, the AAAM is to be com- th*'c virtual|y *be entire range of Navy tactical aircraft: the F-14,
p6 .A-18 Hornet, and the A-6 intruder, as well as the future Advanced (,acl'caI Fighter, the Advanced Tactical Aircraft (A-6 replacement), and a ,C ^'r Force F-15 Eagle. All of these aircraft are candidates lor the lj,Vanced medium-range air-to-air missile (AMRAAM AIM-120). It is that the AAAM is envisaged as a replacement for both the Phoenix and <he AMRAAM.
Preading long-range air-to-air missiles among more types of carrier ^rcraft should have a profound effect on carrier air wing composition. bv'rrently, lbe number of offensive aircraft (A-6s and F/A-18s) is limited y the need to provide, “overhead” in the form of F-14s for fleet air defense and S-3 Vikings for long-range antisubmarine (and limited antiship) attack. If each F-14 could engage more targets and the strike aircraft could perform some part of the F-14s’ function, the number of F-14s might be reduced. The F/A-18 can function as a fighter (limited by its weapon range) and an attack bomber. In the past, a radical approach to the all-strike wing was proposed—an antisubmarine pod. which an A-6 could carry, transforming it into a second-rate S-3.
Given the variety of radar systems on aircraft that will carry it, the AAAM must have some kind of add-on fire control system. The list of platforms also limits the AAAM's weight, which means that the F-14 will be able to carry it in substantial numbers.
Presumably, the missile will be designed to deal with high-speed and highly maneuverable targets. Current long-range rockets, such as the Phoenix, burn out early in their flights, relying on their momentum to carry them to their targets. As a result, they can be evaded, particularly at long range. Possible solutions include a multipulse rocket and ramjets.
This problem also afflicts current surface-launched antiaircraft missiles. Presumably, AAAM technology will feed into any program to replace the current Standard missile, or to supplement it with a longer- range advanced surface-to-air missile (ASAM).
The ASAM and AAAM are complementary approaches to the outer air battle problem of destroying Soviet missile-carrying bombers before they release their weapons. Aircraft-launched missiles such as the AAAM are usable even in the presence of intense jamming because their platforms have some autonomous capability. A ship can carry larger numbers of weapons, but they require some form of forward targeting because the targets are beyond their horizon.
For some years, General Dynamics has displayed a small-diameter, rocket-propelled AAAM candidate that uses a pulse-doppler radar pod. The company is now teamed with Westinghouse in the AAAM competition.
Hughes Aircraft and Raytheon formed a competing partnership—H&R. They propose a ramjet with dual-mode, long- range radar and infrared guidance. Raytheon will be responsible for the radar, and Hughes will provide the infrared portions of the system and handle overall system integration. H&R will subcontract to McDonnell Douglas for the airframe and engine.
The Navy expects to issue two parallel contracts for prototypes.
Commission Studies Sealift
The Commission on Merchant Marine and Defense began hearings at the Center for Defense Analyses in February. The commission was created largely at the behest of Congressman Charles Bennett (D-FL). and is chaired by former Senator (and retired Navy Rear Admiral) Jeremiah Denton. The commission is investigating the likely consequences of the continuing decline of the U. S.-flag merchant Beet. This is not a new topic, but over the past few years it has become increasingly apparent that the United States may have to fight a protracted nonnuclear war.
139
r°ceedings / Julv 1987
Sea Eagle
requiring sustained shipping capacity, both military and economic. Moreover, in recent years, the non-U. S. NATO merchant fleets have declined sharply, so the wartime cushion they represented may no longer be available.
It is difficult to obtain meaningful figures on the state of the U. S. merchant fleet because substantial numbers of Military Sealift Command ships and even oceanographic research ships are included in the U. S. registry. Given that caveat, as of January 1987, the United States ranked 12th (by numbers of ships of 1,000 gross registered tons or more), with 473 active ships. Of the other NATO allies in the top ten merchant fleets (by tonnage), Greece ranked fifth (1,347 ships), Italy ninth (588 ships), and the United Kingdom eighth (599 ships). However, three flag-of- convenience states figured high in the list: Panama was first (3,334 ships), Liberia third (1,571 ships), and Cyprus seventh (964 ships). Japan has the fourth largest fleet with 1,552 ships. It should be recognized that 1,000 tons equates approximately to a 180-foot steel ship; even in World War II, merchant ships usually exceeded 5,000 tons.
These figures change their significance in the face of probable war losses. It is quite clear that NATO has sufficient ships to transport material across the Atlantic in wartime—if no ships are sunk or damaged and ports operate efficiently. That would surely be true at the outset, particularly if the alliance had sufficient war warning. However, if the scenario is a protracted nonnuclear conflict, sea transport has to be maintained in the face of serious attacks on ships and on their ports. If convoying is imposed, it reduces the efficiency per ship, because ships must wait at their ports to assemble.
In World War II, imports were of little consequence: The issue was whether the United States could project its manufactured products into the European and Asian theaters. However, the U. S. economy has come to depend heavily on imports, not only such vital raw materials as oil, but also of some manufactured materials such as semiconductors. It is by no means clear that overall government policy has been coordinated to take account of this potential problem.
Britain Fires New
The ship-launched version of the British Aerospace Sea Eagle air-to-surface antiship missile was successfully fired for the first time in April. The Royal Navy and Royal Air Force use an aircraft-launched version of Sea Eagle, but the navy chose the U. S. Harpoon as the antiship weapon for its
new Type-23 frigate. The ship “ BRITISH AEROSPACE
launched version is derived from a helicopter-launched version developed for the Indian Navy, which has also bought the missile for its own Sea Harriers. India is, therefore, a likely customer for the ship-launched version, as is Chile. The Sea Eagle is powered by a turbojet and employs an active radar seeker that is switched on when the missile approaches the estimated location of its target. It is larger than a Harpoon and presumably carries a more powerful warhead.
Microprocessors Cut Costs
For years it has been claimed that low-cost microprocessors could dramatically reduce the cost of sophisticated military equipment. Two examples were displayed recently.
Texas Instruments has an expendable aircraft-launched decoy (a miniature jammer) that can be dropped from the standard aircraft chaff dispenser. It is about five inches long and about an inch in diameter. This is a very striking development: In the past, so small (and inexpensive) a volume could hold only a simple radar reflector (chaff), which is easily distinguished by its slow motion. A miniature active jammer can do much more, but in the past such decoys could be carried only by very large aircraft, and tactical jammers were always on-board devices.
Sippican displayed its version of the low-cost sonobuoy, which includes a multielement array and some autonomous processing. Even so, the cost target is about $30 per unit, for a projected purchase of about 500,000 sonobuoys per year.
The low-cost sonobuoy concept is that, given Soviet silencing, it may no longer be possible to depend on long-range passive sonobuoys. However, it may still be possible to achieve reliable, relatively short-range detection. That in tum is useful only if much larger numbers of sonobuoys can be used to fill the same area currently searched by small numbers of long-range buoys. Each buoy should be able to “ring a bell and call in an airplane for more detailed search, for example, by a directional active buoy.
Iran to Launch Mini-sub?
The Iranian Central News Agency reported in early May that the Islamic Revolutionary Guard Corps (IRGC) Navy was about to launch its first submarine. This is almost certainly a reference to a small submersible for harbor attack; the IRGC is a paramilitary organization that supplements conventional Iranian armed forces. Given the very limited success of more conventional Iranian attacks on shipping in the Persian Gulf, the IRGC announcement may indicate that unconventional midget craft assaults are to be expected. Submersibles might also be used to attack oil terminals and, particularly, the oil delivery pipes offshore.
The IRGC announcement emphasizes a weak point in the U. S. naval posture abroad. Currently, there is no reliable means of detecting and killing submersibles operating in crowded harbors. U. S. warships d° send out their boats to patrol (and, one hopes, to stop swimmers and explosive boats), but they do not operate their sonars in harbor. Nor do they carry the standard World War II countermeasure—depth charges dropped at intervals to destroy such craft by shock.
Midget submarines and manned torpedoes (chariots) were quite effective during World War II, and countermeasures attracted considerable attention in the early postwar period. Little interest has been shown since the early 1950s, though several navies now operate small submersible craft and such craft can be bought on the recreational market.
At the time of the Iranian Revolution, Iran had several German submarines on order. They were cancelled, and it is very unlikely that the Iranian Government has been able to order full-size submarines from Germany or any other country.
SH-60F Makes First Flight
The prototype Sikorsky SH-60F, designed to replace the existing SH-3H Sea King on board U. S. carriers, flew for the first time in April- Although it shares a common airframe with the SH-60B LAMPS (light airborne multipurpose system) Mk-III helicopter, the SH-60F will have a medium-frequency, active dipping sonar (probably the Bendix AQS" 13F), so that it can operate in the very noisy area near its carrier. It will also have provision for sonobuoys. Compared to the Sea King, the SH- 60F lacks a high-definition radar and, reportedly, provision for nuclear depth charges. The latter change would be consistent with the decision to develop only a torpedo-armed (i.e., non-nuclear) version of the new Sea
Lance (submarine ASW standoff) missile.
The SH-60F was first ordered early in 1985, and as many as 175 are scheduled to be purchased.
The SH-60F program does not appear to include a long- range active sonar, but there seems to be increasing interest in lower-frequency, helicopter- borne systems, which might be capable of convergence-zone range. Such capability might be applicable to the LAMPS mission, and might replace LAMPS passive sonobuoys if at least some cases. In 1986, Plessey announced the Cormorant, which uses extendable arms to enlarge its effective aperture. Bendix has been developing its own HELRAS system under an Italian contract for the Anglo-Italian EH-101 helicopter. Martin-Marietta has displayed its own ALWS low-frequency dipping sonar, which is under development for the U. S. Navy and ultimately intended for the SH-60F, LAMPS, and the SV-22 Osprey. The company claims that the total market may be as many as 850 units.
140
Proceedings / July 198^