The Sky Bow, or Tien Kung (), are a series of surface-to-air anti-ballistic missile and anti-aircraft defense systems developed by Taiwan's National Chung-Shan Institute of Science and Technology (NCSIST). Development of the TK-1 was completed in 1986 and this system is now retired. The TK-2, TK-3 and TK-4 are in service with the Military of the Republic of China.
Development Research into what became the Sky Bow project began after the United States ended bilateral relations with the Republic of China in 1979. Other names proposed by chief engineer Chen Chuan-hao for the project included Sky Horse (Pegasus) and Flying Horse. Upon formal approval of the project in October 1980, it became known as Sky Bow. Under the influence of aerospace engineer and rocket scientist Huang Hsiao-tsung the project expanded to include testing of ramjet motors. In 1981 the project received increased support from minister of defense Sung Chang-chih and was expanded into a general purpose air defense project benchmarked to the American Patriot and Soviet 2K12 Kub. Sung set a seven year deadline for the project. The first test flight in 1982 ended in failure as did other early test flights. Huang left the project in 1982 for an executive role at NCSIST.
In 1984 Taiwan gained the cooperation of Raytheon and was allowed to examine semi-obsolete missiles in detail. NCSIST experts traveled to the United States studied the technology, but they were not allowed to ask any questions and quickly came to the conclusion that many of the missiles they had been allowed to examine were old and had been damaged while in storage. Dedicated facilities needed to be constructed to support the development of the TK-1 including Taiwan's first hypersonic wind tunnel. In 1986 the 12th flight test ended in a successful intercept of a target aircraft, the system's first. The system was officially unveiled in 1986 at a large ceremony presided over by premier Yu Kuo-hua. Its designation it was given, Zhongzheng 100/Sky Bow 1, referred to its 100km range.
Missiles initially used a semi-active radar homing seeker. A passive infrared homing terminal seeker was also developed as a secondary seeker for the TK-1, this was successfully tested against a HAWK missile target but was never put into production. NCSIST also developed a large multifunction, phased-array radar known as Chang Bai (long white) for use with the Tien Kung (Sky Bow) series surface-to-air missile systems with 120 degree coverage and a maximum range of 450 km. Two versions of the phased array radar exist, a towed trailer radar and fixed "hardened" radar sites.Mei, Fu S. "Medium Range Air Defense Radar," Taiwan Defense Review, June 19, 2006."Tien Kung Weapon System" Chungshan Institute of Science and Technology The Chang Bai radar system is reported to be based on the Lockheed Martin's ADAR-HP (Air Defense Array Radar-High Power) design and operates in the 2–4 GHz range (S-band). At least seven systems were said to be in service in 2006. The system performance specifications remain classified, but its effective detection range against a 1m2 target is reported to be around 400 km.
There was also a mobile version of the phased array radar developed in the late 1990s which could provide all-round radar cover with four separate faces but with a much decreased detection range. This version only appeared in public once but was never put into service. The development of Sky Bow 2 started around 1986, this added a tandem boost motor and an active radar homing terminal seeker. Proposals were reported to develop Sky Bow 2 into a surface-to-surface missile; unconfirmed reports suggest that this missile is known as Tien Chi. Modifications have been developed for Sky Bow 2, changing it into a single-stage rocket and to provide it with a limited capability against shorter-range ballistic missiles; the first test firing against a ballistic missile target was reported in September 2008.Mei, Fu S. "Taiwan Tests TK-2A ATBM," Taiwan Defense Review, September 18, 1998. Seven batteries were in service in 2006. In 2010 TK-1/2 SAMs were in service and deployed throughout Taiwan, on the Pescadores, and Dong Ying island."The Balance of Air Power in the Taiwan Strait" US-Taiwan Business Council, May 2010.
Chen claims that the Sky Bow I project was completed in less time and using less money than any comparable air defense system. The project was NCSIST's first ambitious weapons project and its success would have a large influence on the organization.
Sky Bow I
The Sky Bow I (TK-1) (, Tien Kung I) is a surface-to-air missile (SAM) system developed by the NCSIST in Taiwan. Originally based on the aerodynamics of the MIM-23 Hawk missile, the original missile design resembled a scaled-up Raytheon AIM-54 Phoenix.O'Halloran, James C. "Tien Kung I low-to-medium-altitude surface-to-air-missile system, pages 299-300," Jane's Land-Based Air Defense, 2002-2003 Edition. The TK-1 missile was subsequently redesigned and eventually became very similar in appearance to the US Patriot missile after the US government allowed Raytheon to transfer 85 percent of the MIM-104 Patriot missile technology. There is no track-via-missile (TVM) homing capability as this technology was not included in the technology package licensed to Taiwan; the TK-1 system operates in a similar manner to the US Standard SM2 missile, requiring an illuminating radar during the terminal phase.
The TK-1 is designed primarily to target low and medium altitude attacks. Each TK-1 battery has one Change Bai 1 (Long White 1) S-Band phased-array radar for search and target tracking and two CS/MPG-25 target illuminator radars that operates in the X-Band (18–32 GHz) range for the terminal phase, servicing three or four 4-round missile launchers. The combination of inertial/autopilot and mid-course command guidance with a terminal semi-active radar seeker allows the TK-1 missile to fly an energy-efficient flight path to the vicinity of the target where the seeker's semi-active radar would then receive target illumination for the final seconds of the engagement, giving the target minimum amount of time either to evade or commence electronic countermeasure (ECM).
Two versions of the missile launcher exist, one is housed in underground shelters designed to survive an intensive attack. The other is a towed mobile version, and is an integral part of Taiwan's dense air defense network. In addition to bases on Taiwan proper, the TK-1 has also been deployed by the ROC Army on the outlying islands of Penghu and Dong Ying, bringing all of the Taiwan Strait and parts of the PRC's Fujian, Zhejiang and Guangdong Provinces within range.
It was reported in Jane's Missiles and Rockets, August 2006's issue, that the Tien Kung 1 surface-to-air missile (SAM) system would be retired. The TK-1 missiles would be replaced with TK-2 missile rounds and the existing TK-1 system would be upgraded with radar and training simulator to the Tien Kung II standard.Richardson, Doug "Taiwan switches from Tien Kung I to Tien Kung II," Jane's Missiles and Rockets, August, 2006.
CS/MPG-25 target illuminator radars The CS/MPG-25 X-band target illuminator radar entered service in the late 1980s. It has a reported maximum range of 222km and a ceiling of 30,480m. The CS/MPG-25 is a continuous wave disk antenna illuminator radar that was indigenously developed by NCSIST, and was derived from the I-HAWK AN/MPQ-46 High-Power Illuminator (HPI) radar but is estimated to be 60 percent more powerful in output with improved EW, ECM, and IFF capabilities. It is tied into the main phased-array radar on a time-share basis similar to that employ by the US Navy's AEGIS air defence system, allowing the TK-1 surface-to-air missile system multiple target engagement capability.
General characteristics Primary Function: surface-to-air missile Power Plant: Single-stage dual-thrust solid-fuel rocket motor Launch platform: Towed quad launchers and underground silos Length: 5.3 m Diameter: 0.41 m Weight: 915 kg Top Speed: Mach 4.0 Range: 70 km Guidance: Inertial with mid-course guidance update from ground-based phased array radar, Semi-active radar homing (SARH) for terminal guidance Date Deployed: 1986
Sky Bow II
The Sky Bow II (TK-2) (, Tien Kung II) is a SAM system also developed by the NCSIST. Originally a TK-1 with a first-stage booster, the system became a slightly-enlarged modified version of the Sky Bow I (TK-1) missile using an X-Band active-radar seeker,Mei, Fu S. "CSIST Seeks New Seeker," Taiwan Defense Review, January 15, 2002. with a longer range and limited anti-missile capability. The TK-2 active radar seeker operates in the 28–32 GHz frequency range and provides reasonably good performance against air-breathing targets of typical aircraft size. The X-Band active radar seeker used on the TK-2 SAM system was developed from licensed radar technology that NCSIST purchased from the U.S. in the 1980s. The system uses the improved Change Bai 2 (Long White 2) multifunction radar which entered service in the late 1990s. The first public test of the TK-2, codenamed Magic Arrow 43, occurred on May 10, 2002 during the Han kuang 18 exercise.
The TK-2 also has the added benefit of being able to use the same box launcher as the TK-1. Internal components were replaced with miniaturized parts to take advantage of modern electronics technologies, yielding extra room within the missile for more fuel and a more powerful main rocket motor. The TK-2 possesses only modest capabilities against ballistic missiles but is highly effective against aircraft.
General characteristics Primary Function: surface-to-air missile Power Plant: Single-stage dual-thrust solid-fuel rocket motor Launch platform: Underground silos and mobile launch vehicles Length: 5.673 mFu S. Mei. "More Sounding Rocket Missions," Taiwan Defense Review, February 11, 2003. Diameter: 0.42 m Weight: 1,135 kg Top Speed: Mach 4.5O'Halloran, James C. "Tien Kung II, pages 298-299," Jane's Land-Based Air Defense, 2002-2003 Edition. Warhead: 90 kg Range: 150 km Guidance: Inertial with mid-course guidance update from ground-based phased array radar, Active radar homing (ARH) for terminal guidance Date Deployed: 1997
Variants
Sky Spear
Sounding rocket The TK-2 has also been modified for use as a sounding rocket to perform upper atmospheric research for the civilian space program. The sounding rocket test vehicle launched on December 24, 2003, measures 7.7m in overall length and 1,680 kg in launch weight.Mei, Fu S. "Taiwan Forming Missile Command," Taiwan Defense Review, February 16, 2004. It reached a maximum altitude of almost 270 km and splashed 142 km down range around 8 minutes after launch into the Pacific.Mei, Fu S. "Satellite Prospects," Taiwan Defense Review, October 20, 2004. The science mission payload was in the weight class and the rocket reached a burnout velocity of 2,000 m/s. According to the report from Taiwan Defense Review, depending on its payload and launch parameters, the rocket can be converted to attain a horizontal maximum range of up to 500 km.
MissionDatePayloadResultSR-I15 December 1998NoneSuccessful first test flightSR-II24 October 2001Tri-Methyl Aluminum (TMA) release experimentSecond stage ignition failure, mission lostSR-III24 December 2003Tri-Methyl Aluminum (TMA)Mission successfulSR-IV14 December 2004Airglow photometer, GPS receiverMission successfulSR-V15 January 2006Ion probe, 3-axis magnetometerMission successfulSR-VI13 September 2007Hydrazine-fueled reaction control system, recovery capsuleMission successful, capsule lost in the sea due to bad weather conditionsSR-VII10 May 2010Ion probeMission successfulSR-VIII5 June 2013Hydrogen peroxide reaction control system, recovery capsuleMission successfulSR-IX26 March 2014Ion probeMission successfulSR-X7 October 2014Ion probeMission successful
Sky Bow III