Military

AIM-152 Advanced Air-to-Air Missile (AAAM)
Outer Air Battle Missile

It is most advantageous to attack enemy bombers prior to the launch of their cruise missiles, and in the mid-1980s it was projected that in the late 199O's, the maximum launch range for Soviet Naval Aviation [SNA] cruise missiles may be up to 300 nm from their intended targets. This led to developments to provide the ability to conduct both offensive and defensive air operations at long distances from the Carrier Battle Group. In the case of defensive operations this meant extending the engagement envelope beyond the existing Area Defense perimeter in to the Outer Air Battle zone. The strategy of shooting down the aircraft before they could launch their ASCMs was viewed as preferable because the aircraft were larger and less numerous than the ASCMs. This strategy of "shooting the archer rather than its arrows" formed part of a long-range air-to-air combat effort that was referred to as the Outer Air Battle.

Modern anti-ship missiles can be launched several hundred miles away in coordinated attacks, combining air, surface and subsurface launches, so that the missiles arrive on target almost simultaneously. The Navy defends against this threat with a number of different systems. In a carrier battle group, fighter aircraft provide the outer layer of defense; Aegis coordinates and protects the inner layer. In the late 1960s, the Navy developed an Advanced Surface Missile System (ASMS). ASMS was renamed Aegis (after the mythological shield of Zeus) in December 1969. The Navy's Aegis system provides area defense for the battle group as well as a clear air picture for more effective deployment of air assets. Aegis enables fighter aircraft to concentrate more on the outer air battle while cruisers and destroyers assume a greater responsibility for battle group area defense.

In the dense air traffic environment of Desert Storm in 1991, the rules of engagement were designed to require dual phenomenological identification of air contacts before engaging. Air Force fighters designed for the similarly restrictive environment of Central Europe had the necessary equipment; Navy fighters designed and equipped for the less crowded outer air battle in defense of the fleet did not and could not be used in some critical Combat Air Patrol (CAP) stations.

The forward Battle Group operations envisaged by the Maritime Strategy of the 1980s prompted aggressive efforts to provide strategic as well as tactical warning to the Battle Group of an impending SNA attack. This prompted some of the earliest and most successful tactical exploitations of national capabilities (TENCAP), including a program which used missile early warning systems to detect and track the exhaust plumes of Soviet naval aviation aircraft in flight. Linked together by real time data links, these assets collectively extended the outer air battle hundreds of miles from the Battle Group, reestablishing a robust barrier that SNA needed to penetrate before it could launch its missiles.

During the 1980s the Navy invested in developing the Phoenix into a robust, long-range, high-energy weapon system, and in the late 1980s embarked on a program to develope an improved follow-on capability in the Advanced Air-to-Air Missile (AAAM). Advanced Common Intercept Missile Demonstration (ACIMD) tests demonstrated the technology and hardware for a highly advanced Sparrow-sized, integral rocket-ramjet propelled, multimode-guided air-to-air missile for the long-range outer-air battle. The Navy planned to maintain and support an adequate Phoenix missile capability until the AAAM is fielded in sufficient numbers. A missile retrofit program incorporating an already developed and demonstrated block upgrade to the AIM-54C was a cost-effective interim solution. As of 1990 it was estimated that it would require at least 10 years to introduce the follow-on Advanced Air-to-Air Missile.

AIM-152 and -155 designated the same missile, AAAM, though there are still arguments about what would have been the proper designation. In October 1988 the US Navy's Naval Air Systems Command (NAVAIR) awarded contracts to two industrial teams for a four-year technology-validation phase of the AAAM. One team was a combination of Hughes and Raytheon, two rival companies which had come to dominate the US market for medium/long-range air-to-air missiles. The other links General Dynamics with Westinghouse.

Hughes used an integral rocket/ramjet propulsion. The advantages were that it was "powered all the way", allowing for greater range and terminal pursuit capability and it was probably a simpler design. It would "fly" through turns. The downside was that it was a bit larger (although that did allow room for more "stuff"), not as flexible and couldn't carry as many. Hughes used an inertial mid-course guidance with command updates and in the terminal phase would use active radar and IR seekers.

GD/Westinghouse use a restartable solid fuel rocket. The GD/Westinghouse missile had folding wing and tail surfaces, delivered from the depot packed in a circular storage/launch tube. The team released artwork showing how 12 of these tubes could be carried in two lateral rows of six under the fuselage of an F-14D. With thrust vectoring on both stages, it was noticeably more maneuverable when under power and at launch It offered greater flexibility, and you could carry more per aircraft. The fact that it was tube launched was both an advantage and a disadvantage. In return for its advantages, development probably would have been riskier. GD/Westinghouse inertial navigation system with semi-active radar homing (possibly dual band) for mid-course guidance and would go autonomous with EO homing at the endgame with IR backup. It would have greater off-boresight capability than Hughes, but the price for that is that the launch aircraft would have to carry a targeting pod on one station, although that pod would have fore and aft radar.

The primary aircraft the missile was designed for was the F-14D, which was the only aircraft that could use it to its full capabilities, but it was also designed to operate from the F/A-18 and F-15 (although USAF didn't want another Navy missile). It would not fit into the F-22's bay, apparently, although word is it would fit into the F-23.

By the end of the 1980s a full-scale airframe had been built. Looking rather like a stretched Standard surface-to-air missile (SAM), this featured long-chord cruciform wings and narrow-chord cruciform tail fins, plus a short tandem-rocket booster. The missile was 12ft long (3-65m), 5.5in (140mm) in diameter, and weighed 3861b (175kg). A first-generation seeker gimbal and a second-generation control section were tested in the early 1980s, while 1983 saw trials on a ground test stand of a heavy-walled prototype of the proposed rocket motor and thrust-vector control (TVC) system. Other tests checked the performance of the proposed warhead against what were described as "RA-5-size targets". A second series of wind-tunnel tests on the missile airframe began in 1983.

Targets would be detected initially either by the F-14D's APG-71 radar or by its infrared search and track system (IRST), then handed over to the ATI pod. This uses its frontfacing antenna to track the targets and compute the engagement envelope for each one. It also has a limited degree of search capability.

The aircrew selects the target to be engaged, then fires the missile. The round will leave the launch tube under the power of its tandem-mounted rocket booster. At burnout this will be jettisoned, and the main solid-propellant rocket motor (sustainer) ignited to power the round for the first stage of its flight out to the target. After launch, the crew is free to maneuver its aircraft to reduce the closure rate. There was no need to keep the aircraft pointed towards the target —a drawback to conventional semi-activeradar-homing-missile attacks. The ATI pod even has a second rearward-facing antenna.

With the end of the Cold War there was a general recognition that the outer air battle -- the battle against Soviet naval aviation bombers -- was significantly reduced in importance. While AAAM was seen as the best defense against the Soviet naval air arm, the future threat would consist of Third World fighter-bomber or diesel-electric submarine. Some also argued that the F-14's the outer air battle long-range air defense mission would be less important in the post-Cold War era, when naval aircraft were expected to be used at shorter ranges in littoral (off-shore) operations in Third-World scenarios. The main problem with the littoral AAW threat is that this depth is largely absent, both because the US Navy seeks to close with its adversaries, and because those adversaries are generally constrained anyway to operations within the littoral battlespace. All of these factors conspire to radically compress an AAW engagement in space and time, reducing the role of the outer air battle, and reducing the number of shots available during the inner air battle. The essence of new threat was supersonic, sea skimming ASCM attacks in the littoral launched from truck-mounted launchers ashore.

This changing security environment doomed this Phoenix missile successor [as well as the associated F-14D Super Tomcat upgrades], and the Advanced Air-to-Air Missile program was cancelled in 1992.