SAI-774 Sayaka
| SAI-774 Sayaka | |
|---|---|
 Several launch configurations of the SAI-774 Sayaka SRAAM. | |
| Type | Short to medium-range air-to-air missile |
| Place of origin |  Carthage |
| Service history | |
| In service | 1999-present |
| Used by | Carthage |
| Production history | |
| Designer | RMA Corporation Cordoba Aerospace |
| Designed | 1994-1998 |
| Manufacturer | RMA Corporation Cordoba Aerospace |
| Unit cost | $650,000 (FY2013) |
| Produced | 1998-present |
| No. built | 195,000+ |
| Variants | SAI-774VL SAR-774 SAI-774AM1 |
| Specifications (SAI-774AM1) | |
| Weight | 125 kg (276 lb) |
| Length | 2.78 m (9.1 ft) 3.38 m (11.1 ft) (w/booster) |
| Diameter | 200 mm (7.9 in) |
| Warhead | 12 kg (26 lb) annular blast fragmentation |
Detonation mechanism | Laser proximity fuse Backup impact fuse |
| Wingspan | 440 mm (17 in) |
| Propellant | 18 cm (7.1 in) solid rocket motor |
Operational range | 50 km (31 mi) (air-to-air) 35 km (22 mi) (surface launch) |
| Flight ceiling | 20,000 m (66,000 ft) |
| Speed | 4,200 km/h (2,600 mph) |
Guidance system | Dual-color imaging infrared focal plane array (SAI-774) Active radar homing (SAR-774) |
Launch platform | Multi-platform |
The SAI-774 Sayaka, formerly classified as the Type-98 is a modern all-weather multi-target anti-aircraft missile system developed and manufactured by the RMA Corporation and Cordoba Aerospace. It is designed to out-range and outrun competing short- and medium-range missile systems while maintaining sufficient maneuverability and off-boresight capability to be useful in close quarters engagements. Both infrared and radar-guided variants of the missile exist, sharing the same warhead, motor, and control systems but using different seeker technologies to engage a variety of targets. Capable of being launched from aircraft and both warship and land vehicle vertical launch systems, the SAI-774 is a fire-and-forget missile with lock-on after launch capability and high maneuverability.
The development program that eventually yielded the SAI-774 started in 1978 following an evaluation of fighter performance in the Northern War, which indicated a need for a more capable short-range missile. Funding and technical delays delayed the project through the 1980s and into the early 1990s as the project was downgraded to a technology demonstrator, although by 1991 sufficient funding to return the program to full development status was approved. Introduced in 1999, it replaced the Type-88 in service with the Carthage Defense Forces.
History
The first extensive use of IR missiles by the Carthage Defense Forces took place during the Northern War, where results failed to meet expectations. The Type-88, the first IR-guided missile in widespread Carthaginian service, achieved hits only 15% of the time. Despite the widespread employment of air-to-air missiles by both sides, dogfights remained a common occurrence as both long- and short-range missiles proved unreliable. Postwar analysis of aerial engagements indicated that a combination of technological immaturity in both missiles and aircraft, restrictive rules of engagement, and a lack of proper training in the use of missiles were the primary factors in this poor performance.
In 1978, the Carthage Air Forces initiated a program to develop requirements for a series of new air-to-air missiles taking into account lessons learned during the war. While funding shortages made the possibility of any such program entering the full development and procurement phase, the program was considered essential in order to develop a path forward for future missile developments. The major requirements identified for new IR-guided missiles included:
- All-aspect capability - The standard Type-88AM1E missile was unable to lock on to targets during head-on engagements, requiring a tail engagement to identify the signature from the target's engines. This prevented the use of IR missiles before the merge and forced pilots to maneuver to line up the seeker head with the target's engines. Tests with more sensitive seekers capable of head-on engagement conducted before the war indicated such performance was possible but no such seekers were fielded before the end of hostilities.
- High off-boresight capability - In the last two months of the war, the first Venetian V3A IR missiles began entering service with 30° off-boresight capability and a helmet-mounted cuing system. These capabilities proved to be a significant advantage in dogfight scenarios as they expanded the engagement envelope beyond near-perfect tail-on shots and allowed the missile to maintain a more reliable lock in the face of evasive target maneuvers. A requirement of at least 60° off-boresight capability was specified.
- Increased range - The Type-88AM1E missile had a practical range of under 8 kilometers (5.0 mi), preventing it from being used unless the pilots were committed to a close-range dogfight. The new requirements specified a range of at least 20 kilometers (12 mi) for future IR-guided missiles.
- Increased maneuverability - The 25 g turn rate coupled with the short range of the Type-88AM1E proved insufficient for reliable interception of very maneuverable targets such as the European Mirage III. A 40 g turn rate was specified as the minimum standard for future developments.
- Better clutter rejection - IR missiles on both sides remained vulnerable to clutter and distraction by natural phenomena (such as the sun and ground reflections) and countermeasures, resulting in very high miss rates even when pilots could successfully maneuver to acquire the target.
The program also identified requirements for a more capable medium- to long-range air-to-air missile to replace the Type-77, which had even more dismal performance results in the Northern War than the Type-88. Several other concepts were also proposed to address the problems of air-to-air engagement, including smaller, more compact short-range missiles that could be fired in larger numbers to overcome performance issues and more cost-effective missiles designed as a middle ground between the stringent new requirements and existing designs. With budgets restricted as a result of the post-war draw down in strength, the Type-77 replacement effort was given funding priority, with a new monopulse seeker, new digital guidance system, new rocket motor, and new warhead combined in the existing Type-77 form factor to create the Type-89 MRAAM which entered service in 1982.
Type-91 program
A prototype for the replacement SRAAM program was developed as the Type-91, incorporating a number of new technologies to meet the specified requirements. The Type-91 incorporated used a larger 15-centimeter (5.9 in) rocket motor for greater range and acceleration and incorporated thrust vector control to improve maneuverability up to 45 g. To reduce aerodynamic drag and maximize range, the missile body was clean except for a single set of fixed fins at the rear and a new large-format, high off-boresight seeker was mounted in the nose. The combined effect of these improvements also increased missile weight to 95 kilograms (209 lb) from the Type-88's 78 kilograms (172 lb).
In 1981 this prototype was evaluated against the Type-88AM2A, a significantly upgraded variant of the original Type-88 missile. While the Type-91 exhibited noticeably better performance than the upgraded Type-88 especially in terms of kinematics, budget shortfalls prevented any serious consideration of the Type-91's procurement for service and the program was downgraded to a technology demonstrator and extended research project to further develop designs for future use. The Type-88AM2A was further refined to the Type-88AM2B and entered service in 1984, adopting the cleaner body of the Type-91 but not the larger motor or sensor. Work continued on the Type-91 program throughout the 1980s and included tests of newer and alternative seekers, alternative body designs, and newer rocket motors with more modern propellant formulas.
Future SRAAM program
By the early 1990s, experience in the Second Pacific War and the Argentine Intervention demonstrated the need for further improvements in the Carthaginian air-to-air missile inventory. The improvements to the Type-77 in the form of the Type-89 were not sufficient in terms of increased engagement range and the Type-88AM2B still suffered from a relatively limited off-boresight angle and short range. It was furthermore expected that the Fighter Modernization Program, later to become the Advanced Multirole Program, would require modification to existing missiles for compatibility with internal carriage standards.
In 1992, the Air Forces and Navy agreed to co-develop a new set of air-to-air missiles to arm both the current fighter fleet as well as the in-development Advanced Multirole fighter. While a common set of requirements were developed by both branches for both missiles, by mutual agreement the Air Forces would act as the lead project manager for the Type-89 replacement (which became the SAR-778 Sakura) while the Navy would manage the Type-88 replacement, which would become the Type-98.
Operational features summary
The SAI-774 Sayaka was developed to meet several key requirements identified in the 1970s for a new short-range air-to-air missile. As a result, the SAI-774 was designed to include both all-aspect and high off-boresight (HOBS) capability while also providing significantly increased range and agility.
Sayaka was developed in two primary variants, the IR-guided basic SAI-774 and the radar-guided SAR-774. Both use the same body, motor, and warhead and have interchangeable seekers. The infrared version uses an imaging infrared focal plane array with up to 160° tracking for high off-boresight maneuvers as well as lock-on after launch capability when cued by a launch vehicle. The IR variant is distinguished by the large sensor dome in the nose which provides the large dual-color sensor an enormous field of regard. The active radar variant uses an electronically-scanned planar array antenna for detection and is visually distinguished by an opaque nosecone in place of the transparent sensor dome.
Steering is provided through a combination of thrust vector control and four aerodynamic control surfaces at the tail for extreme agility with relatively low drag. Compared to the Type-88, the SAI-774 is faster, has a significantly longer range, and is more resistant to ECM and physical decoys than its predecessors, resulting in a higher kill probability.
For surface-launched variants, a booster is attached to reduce range loss from lower-altitude, lower-speed surface platforms. It is commonly used on warships as a short-range interceptor against aircraft and cruise missiles and as a short-range air defense missile for ground formations. All surface-launched and newer air-launched versions incorporate folding fins for better stowage in contained spaces.
Missiles can be fired in either hit-to-kill or proximity modes. Hit-to-kill is more commonly used in the surface-launched version as an interceptor while proximity detonation is the standard engagement type for air-launched missiles.
Description
Seeker
The IR-variant SAI-774 variant uses a cooled 512×512 element dual-color imaging infrared (IIR) focal plane array, enabling acquisition at extended ranges and strong resistance to countermeasures. The seeker can discriminate against flares and has greatly improved head-on engagement range relative to the preceding Type-88. It is also sensitive enough to make out individual components of a target aircraft, and can be tasked to target specific parts. The seeker is capable of locking on to targets within a 320° cone and when connected to a compatible pylon can be used as a supplementary IR sensor by the host aircraft. The IR seeker is contained within an artificial sapphire dome and is protected by a canvas cover that is removed before launch.
The SAR-774 variant uses an electronically-scanned planar array antenna for targets with low IR signatures or for use in environments with significant infrared clutter, although is more rarely deployed than its IR-guided sibling. Both variants can accept targeting data and cuing after launch, allowing targets to be engaged from any angle. The RF seeker is protected by a composite nosecone rather than the sapphire seeker used in the IR variant.
For both IR and RF variants, the larger body diameter of the SAI-774 missile body enables the use of seekers much larger and more powerful than are commonly used on other short-range missiles in the 130-millimeter (5.1 in) and 160-millimeter (6.3 in) size class. The IR seeker is cooled by an electric Stirling engine while active, eliminating the need for the compressed gas coolers previously required and allowing the seeker to be cooled indefinitely using aircraft-supplied electrical power. In flight, the seeker and guidance servos are powered by a thermal battery.
Fuze
Three fuzes are normally carried: a primary laser fuze, a backup impact fuze, and a timed self-destruct fuze. The laser fuze allows proximity detonations to increase kill probability against aircraft, eliminating the need for a direct impact. In the event of failure, the impact fuze will automatically detonate the warhead upon collision. The self-destruct fuze activates after the missile has expended its motor and it cannot acquire any further targets.
Warhead
All models are equipped with a 12-kilogram (26 lb) continuous-rod warhead. When detonated, the bundle of rods around the explosive charge rapidly expand, forming a cutting ring of metal designed to slice through aircraft components. Fatal proximity range is estimated to be 10 meters (33 ft) for normal aircraft.
Propulsion and control
Sayaka uses a conventional low-smoke solid rocket motor with thrust vectoring in conjunction with conventional aerodynamic control surfaces. Relative to the 13-centimeter (5.1 in) motor used in the Type-88, the 18-centimeter (7.1 in) motor provides significantly increased thrust and range, improving performance against fast targets including tail-on engagements. The LPM-1704 motor provides an engagement range estimated by be greater than 50 kilometers (31 mi) with significantly greater acceleration off the rail than the Type-88.
The wide missile body provides sufficient body lift that lifting devices are not necessary, leaving the outer surface free of any drag-inducing protrusions. The only external surfaces are the four guidance fins at the rear whose control is supplemented by the rocket motor's TVC. With both control mechanisms, the missile is capable of maneuvers at up to 65 g and turn rates of 100°/sec, allowing it to engage both extremely agile fighters as well as smaller targets such as cruise missiles and drones. The use of TVC also allows the missile to begin maneuvering immediately after launch without the need to reach a minimum speed for aerodynamic control to properly function.
Control surfaces on all models incorporate folding fins to the missile to be stored in internal payload bays and quad-packed in VLS tubes.
Datalink
The onboard datalink allows missiles to be cued against targets after launch, enabling lock-on after launch capability. The radar version is capable of track-via-missile homing but this feature is rarely used. Following the introduction of the SAR-778 Sakura, datalink architecture and hardware was standardized between the two missiles beginning with the AM1 specification, and was incorporated in subsequent models.
Maintenance and support
Initially missiles were delivered as standard stand-alone units, but current models are packaged as sealed rounds in storage containers that can either be dropped directly into a VLS or stored in a carrier or base's automated weapons handling system. Onboard sensors monitor the weapon's status and can report any faults, allowing the defective unit to be returned for repairs. For air-to-air use the missile is removed from its canister but can be replaced if not expended.
Launch platform
The SAI-774 can be stored and launched from any Mark 18 vertical launch system installed on nearly all Carthaginian and most Shogunate warships. For warship use, it is normally quad-packed into each Mark 18 VLS cell to maximize space. Land-based truck launchers also exist as part of the Tarnhelm air defense system.
The SAI-774 can also be launched from nearly any fighter and a number of attack helicopters as well as ground vehicles. With folding fins, the SAI-774 is capable of being carried in both the main and side weapons bays of the RFM-202 Shaheen and other Carthaginian fifth-generation fighters. The Common Missile Rail Adapter was introduced with the Sayaka, which provides a new universal mounting platform for the SAI-774, SAR-775, and SAR-778 air-to-air missiles.
A unique submarine-launched variant was also developed for the Type-060 submarine family, composed of the missile sealed in a container with a flotation device. When launched, the canister floats to the surface and the sealing cap is released, exposing the missile seeker. The seeker is programmed to scan for a target and upon locking on to a hostile aircraft can launch from its canister to engage.
Variants and upgrades
- SAI-774: Initial production air-to-air model, with 105,760 missiles delivered to date. The SAR-774 was delivered at the same time with 54,000 missiles ordered. Both have been retired but remain in stockpiles, with most slated to be slowly returned to the factory for reconditioning, and final deliveries concluded in 2007.
- SAI-774VL: Original vertical-launch variant, identical to the air-launched variant except for the use of the vertical launch booster and turnover module. 44,500 units of both IR and RF types were delivered through 2007.
- SAI-774AM1: Upgraded model in current service, including the SAR-774AM1 RF-guided model. It incorporates a more advanced electronics package along with a new warhead compliant with insensitive munitions standards. 127,000 models have been delivered so far.
- SAI-774AM1VL: Vertical-launch variant of the improved SAI-774AM1 equipped with the VL booster and turnover module. 21,500 units delivered through 2016.
Operators
- Carthage
- Army of Carthage
- Tarnhelm air defense system
- Carthage Air Forces
- Punic Navy
- Mark 18 vertical launch system
- Army of Carthage