K9 Thunder

K9 Thunder
Type - Self-propelled artillery
Place of origin - South Korea
Service history
In service - K9: 1999-present / K9A1: 2018-present
Wars - Bombardment of Yeonpyeong
Production history
Designer - Agency for Defense Development (main developer) / Dongmyeong Heavy Industries (turret and suspension) / Kia Heavy Industry (main armament) / Poongsan Corporation (ammunition) / Samsung Aerospace Industries (structure and production)
Designed - 1989-1998
Manufacturer - Samsung Aerospace Industries (1998-2000) / Samsung Techwin (2000-2015) / Hanwha Techwin (2015-2017) / Hanwha Land Systems (2017-2019) / Hanwha Defense (2019-2022) / Hanwha Aerospace (2022-present) / Turkish Land Forces (2001-present) / Huta Stalowa Wola (2017-present) / Larsen & Toubro (2018-present) / Military Factory 200 (2023) / Hanwha Defense Australia (2024)
Unit cost - 4 billion KRW (for the ROK Armed Forces)
Produced - K9: 1998-2017 / K9A1: 2017-present
No. built - 1,700 (2020)
Variants - K10 ARV / K11 FDCV / T-155 Fırtına / AHS Krab
Specifications
Mass - 47 t (combat)
Length - 12 m (7.44 m, hull)
Width - 3.4 m
Height - 2.73 m
Crew - 5 (Commander, Driver, Gunner, 2 Loaders)
Maximum firing range - 18 km (M107, HE) / 30 km (M549A1, RAP/HE) / 36 km (K310, BB/DP-ICM) / 40 km (K307, BB/HE) / 54 km (K315, BB+RAP/HE)
Armor - POSCO MIL-12560H armor steel (domestic only, after 2022) / Bisalloy Steel armor steel (export variants, after 2022)
Main armament - Hyundai WIA CN98 155 mm 52 caliber, 48 rounds
Secondary armament - SNT Dynamics K6 12.7x99 mm NATO HMG
Engine - STX Engine/MTU Friedrichshafen MT881Ka-500 8-cylinder water-cooled diesel engine (735 kW (1,000 hp) @ 2,700 rpm)
Power/weight - 21.3 hp/t
Transmission - SNT Dynamics/Allison Transmission X1100-5A3 (4 forward, 2 reverse)
Suspension - Mottrol Hydropneumatic Suspension Unit (HSU) (travel distance: ≤ 275 mm / dead weight: 40 ~ 45 kN)
Ground clearance - longitudinal slope: 60 % (lateral slope: 30 % / vertical: 0.75 m / trench: 2.8 m / fording: 1.5 m)
Operational range - 360 km
Maximum speed - 67 km/h

The K9 Thunder is a South Korean 155 mm self-propelled howitzer designed and developed by the Agency for Defense Development and civil contractors including Dongmyeong Heavy Industries, Kia Heavy Industry, Poongsan Corporation, and Samsung Aerospace Industries for the Republic of Korea Armed Forces, and is now manufactured by Hanwha Defense. K9 howitzers operate in groups with the K10 automatic ammunition resupply vehicle variant. The entire K9 fleet operated by the ROK Armed Forces is now undergoing upgrades to K9A1, and a further upgrade variant K9A2 is being tested for production. As of 2022, the K9 series has had a 52% share of the global self-propelled howitzer market, including wheeled vehicles, since the year 2000.
Development
In the 1980s, the ROK Armed Forces came in need of a new artillery system to contest North Korean equipment. The armed forces operated M107 self-propelled guns and K55 self-propelled howitzers; however, they had shorter firing ranges compared to M-1978 Koksan and were outnumbered by various North Korean artillery. With the success of designing and manufacturing KH178 105 mm and KH179 155 mm Towed Howitzers, and experience gained by license producing K55 (KM109A2), the Ministry of Defense ordered development of a new system that would have a longer firing range, faster firing rate, and high mobility. The development started in 1989 and was led by the Agency for Defense Development (ADD) and Samsung Aerospace Industries (now Hanwha Defense).
Since 1983, the ADD researchers have been collecting and analyzing data for future artillery. They saw that burst fire and quick relocation would become the dominant factor in artillery battles and built an automatic loading system for testing in 1984. In 1987, the ADD offered an upgrade plan to the existing K55 inspired by the United States' M109 Howitzer Improvement Program (HIP), but was rejected by the Republic of Korea Army in 1988. As a result, and at the beginning of K9 development, the ADD was determined to create a new weapon system and worked on a conceptual model until 1991. Early concepts requested by the military included river crossing capability and the installation of M61 Vulcan as an anti-air weapon, which were later removed due to being unnecessary for such a long-range weapon.
In 1989, the only design data the researchers could obtain at that time were the provisions of the four-nation ballistic agreements, namely the United States, the United Kingdom, Germany, and Italy, to secure the homogeneity of the ammunitions-the new 52 caliber gun fires a NATO standard ammunition (L15A1) at a speed of 945 m per second from chamber volume of 3,556 cm3. The first domestic design was prepared by extending and modifying the 155 mm 39 caliber gun used for the KH179. The first firing test was held in January 1992 but experienced many problems due to design errors.
In September 1990, a Korean developer visited the United Kingdom in search of turret design technology which was known to have been developed by British Vickers for AS-90. However, Vickers refused the technology transfer; instead, the company offered the AS-90 for sale. The developer also visited Marconi, but the negotiations ended with an unsatisfactory result due to a high price to pay being requested. Therefore, developers went for domestic electrohydraulic driving system using the experience in turret design and turret driving devices of K1 MBT, and the simulator was built in 1991. Next year, researchers found that the disproportionate moment of the 52-caliber was twice of the K55; the balancing machine, which increased the capacity of the existing hydraulic balancing machine, did not sufficiently compensate for the imbalance moment value due to the change in the position of the armament, and the driving force was very different depending on the driving angle. The same problem also appeared in Germany's Panzerhaubitze 2000, which was under development. However, a joint research team from the ADD and Seoul National University of Science and Technology calculated an accurate theoretical model, and concluded that adjustment to system configuration was possible without major design changes. Meanwhile, loud noise from hydraulic generators, which can cause hearing loss under long exposure, was also a problem. The engineers of the ADD and Dongmyeong Heavy Industries (now Mottrol) found that the noise was due to excessive shaking of hydraulic pressure, thus creating an experimental device using the principle of Helmholtz attenuators used in car mufflers. The noisy equipment became quieter and the hydraulic pulsation was significantly reduced. Overall, the domestic design showed driving precision of less than 1 mil in the standard error range.
In the winter of 1991, the ADD held talks with engineers from Samsung Aerospace Industries' special research institute. The ADD originally demanded that Samsung be in charge of system assembly only, as the company had no experience in developing its own tracked vehicle design despite having the experience in manufacturing K55 under license. However, the decision was overturned and the manufacture of the MTR (Mobility Test Rig) was decided. Samsung also worked with KAIST on suspension and Seoul National University & Pohang University of Science and Technology on mobility systems. The engine was co-developed with American AAI Corporation. The test of the MTR was finished in November 1992.
In April 1992, BMY Combat Systems (now BAE Systems Land and Armaments) invited members of the ADD for its first M109A6 Paladin release ceremony and expressed interest in participating in Korea's self-propelled howitzer program by upgrading K55 to Paladin standard. In May, members of BMY Combat Systems and Taledyne Brown visited the ADD, and suggested co-development of a new howitzer based on P-52, a 52-caliber Paladin variant, but this proposal was rejected by Korean developers. Later, during Data Exchange Agreement meeting, South Korea and the United States confirmed that the U.S. has no claim to any intellectual property rights of the howitzer to avoid possible disputes in the future.
From 1992 to 1993, the developers explored and confirmed the required operational capability, such as the system suitability of major components and the possibility of reaching the maximum firing range of 40 kilometres (25 mi). An internal review predicted that the howitzer would achieve a localization rate of 107 out of 235 (45.5%) technologies by the late 1990s. Unsatisfied with the review, South Korea decided to continue developing its domestic main system, main gun, 155 mm ammunition, fire control system, structure, and autoloader. On the other hand, the engine, transmission, and INS (inertial navigation system) were chosen to be imported from foreign partners, and license produce hydropneumatic suspension to boost up localization by 70%. The engineers faced the biggest challenges designing main gun and suspension due to lack of experience; while licensing the K55, its main gun was brought as finished product and suspension was produced under knowledge base from the United States.
Based on a review of the required operational capability in October 1992, a firing rate of three shots within 15 seconds was chosen for economic feasibility. The rationale was that it is difficult for targets to be out of fatal range within 15 seconds after the first impact, and that the firing rate can be shortened depending on training level. If a firing rate of three shots in 10 seconds was demanded, it would have caused a huge increase in development costs as well as an unnecessary burden on researchers.
The development was delayed between March to August 1993 as a result of purge of Hanahoe, a private military club within the Republic of Korea Armed Forces who aligned with military dictator Chun Doo-hwan, by president Kim Young-sam who was elected by democratic election. Also, the army logistics department refused to sign the letter of agreement for XK9 until a development plan for the maintenance elements was made. When the Joint Chiefs of Staff finalized the system development agreement in late August 1993, the Defense Ministry approved a prototype development plan in September and the president approved the project in early October.
Since domestically developed armor steel plates will be applied for the first time, the researchers decided to produce and compare armor plates from both imported and domestic materials to reduce the risk. Meantime, Samsung began to train and employ master craftsman welders whose skills were verified by the U.S. Aberdeen Test Center. Armor plates went through a series of tests such as stress and ballistic impacts, and researchers verified that the domestic plate performed better than the imported plate.
The ADD saw that HSU (Hydropneumatic Suspension Unit) provides better mobility and crew comfort. At that time, HSU caused problems with some equipment and it was yet to be fully verified for durability, igniting controversy internationally. Therefore, it was inevitable to introduce and localize British Air-Log HSU that are used for AS-90. However, when researchers applied Air-Log HSU on the MTR and prototypes, they soon found that the HSU couldn't support heavier vehicles, thus failing the durability test. Since May 1997, engineers from the ADD and Dongmyeong Heavy Industries have spent a year on five redesigns and 11 durability tests. After the development of the new HSU, the system was exported back to Britain.
Developers changed the power pack for the MTR with the combination of an 850 hp engine from Detroit Diesel, which offered a smaller cooling system, and Allison Transmission's X1100 automatic transmission. It passed the tests with the MTR, but failed on prototype vehicles due to low durability. The researchers looked for new engines from overseas, and Perkins Engines and MTU Friedrichshafen showed interest in selling the engine in August 1995. Perkins Engine offered the CV12 Condor, which was also used in Challenger 2, but with reduced horsepower to 1,000. The price was slightly higher than that of Detroit Diesel; it was a relatively large 12-cylinder, which would require a design change on the chassis and there was a technical insufficiency of cooling devices. On the other hand, MTU's MT-881, though more expensive, offered a compact eight-cylinder with the same cutting-edge cooling system from the latest Euro Pack. The engine was also used for PzH 2000 in Germany, and was undergoing trials in Germany and Canada. After examinations, the German design was chosen for the program, and was tested on ATR (Automotive Test Rig) for a year starting in September 1997.
In the spring of 1992, the test gun experienced detonator breakage caused by a differential pressure, at which the pressure increases in the opposite direction of the shell. After many years of failures and updates, researchers decided to change the shape of the propellant in 1997. The tiny pellets of the U.S.-style propellant, which have seven holes similar to briquettes, were replaced with 19 holes by mimicking the German style without knowing the specification. After numerous tests, the gun achieved a range of 40 kilometres (25 mi) below 53,000 psi in 1998.
A total of three prototypes were built and performed their first open trials in 1996. During the test, the prototypes succeeded in firing at distances of 40 kilometres (25 mi) and six rounds per minute, but failed to fire three rounds in 15 seconds. On 5 December 1997, one of the prototypes was damaged by fire after testing 18 rounds in three minutes due to failing complete combustion, which resulted in one researcher being killed and two injured. However, the damaged prototype's internal system survived the fire, and thus was repaired for further use. The prototypes fired 4,100 rounds and underwent 13,800 kilometres (8,600 mi) of mobility tests including extreme temperature conditions and various type of terrain such as ski courses during the winter season.
After firing 12,000 rounds and driving 18,000 kilometres (11,000 mi) over 10 years, the development was finished on 12 October 1998 with achieving 87% localization rate. The contract for the first batch of K9 artillery system was awarded to Samsung Aerospace Industries on 22 December 1998. The produced vehicles were supposed to be delivered to the Republic of Korea Army; however, the naval battle between the two Koreas caused the delivery to be rerouted to the Republic of Korea Marine Corps. The first vehicle was rolled out on 17 December 1999, and was given to the marines in Yeonpyeongdo.
General characteristics
The K9 is of welded construction, using 20,000 kilograms (44,000 lb) of MIL-12560H armor steel developed by POSCO for K2 Black Panther project, which can withstand explosion pressure and fragments from 155 mm HE rounds, 14.5 mm armor piercing rounds, and anti-personnel mines all around. The vehicle can protect crews from CBRN threats using an air-purification system.
The power-pack consists of a 1,000 horsepower (750 kW) MT881Ka-500 MTU Friedrichshafen engine licensed by Ssangyong Heavy Industries (now STX Engine) and an Allison Transmission X1100-5A3 transmission licensed by Tongil Precision Machinery Industries (now SNT Dynamics), and is installed on a hydropneumatic suspension chassis. Driven by Firstec driving system, the 47-metric-ton (52-short-ton) vehicle has maximum speed of 67 kilometres per hour (42 mph), and is capable of operating in various terrain conditions including desert, snow, jungle, and mountains. It can also be deployed as self-propelled coastal artillery for surface targets, creating a no-access zone within its firing range.
The main armament is a CN98 155 mm, 52-calibre artillery gun manufactured by Kia Heavy Industry (now Hyundai WIA), with a maximum firing range of 40 kilometres (25 mi) with K307 rounds. Or 54 kilometres (34 mi) with K315 rounds fired from the upgraded K9A1 variant. The K9 stores 24 rounds in the bustle rack while an additional 24 rounds are located at the rear of the hull. Assisted by a semi-automatic feeding system, fire control system, and the Battalion Tactical Command System (BTCS), the vehicle can burst fire three rounds in 15 seconds, with the ability to land shells in multiple rounds simultaneous impact (MRSI) mode. It has a maximum rate of fire of six to eight rpm for three minutes (or until emptying 24 ammunitions store in the bustle rack), then reduced to two to three rpm for sustain fire. The vehicle can shoot-and-scoot and be ready to fire in 30 seconds when stationary or one minute if moving. After firing, it can relocate to a new position in 30 seconds, to increase survivability from enemy counter-battery attacks.
The shells, fed by from a K10 ammunition-resupply vehicle, enter from the door behind the turret and are automatically rolled and loaded on the rack. When the shooting specification is decided, the chosen shell is placed on the tray in the center of the rack. A loader pulls the tray handle, and the shell slides into the carrier. Then the carrier repositions to the angle of shooting, and transfers the shell to the autoloader, which immediately "throws" the shell into the barrel.
The K9 uses the TALIN (Tactical Advanced Land Inertial Navigator) 5000 for its INS, purchased from Honeywell Aerospace after the announcement of the development of a ring laser gyroscope system that can withstand the shock from gunfire. The positioning device consists of a ring laser gyro that can detect up to one-ten-thousandth of Earth's rotational angular velocity, an accelerometer that can detect up to one-hundred-thousandth of Earth's gravitational acceleration, and a navigation computer that calculates using data detected by these sensors. This positioning device calculates the location of the self-propelled gun, the azimuth angle of the gun to the north, and the elevation and inclination angle of the earth's horizontal plane by itself. The calculated navigation information and posture information are provided to the fire control system, which has a positional accuracy within 10 m, an azimuthal accuracy within 0.7 mil, and an elevation and inclination angle accuracy within 0.35 mil.
The K9 has both manual (mechanical and optical) and automatic (electronic) fire control system. The manual fire control system is similar to that of K55, while the AFCS consists largely of a system controller, display, a shooting controller with a built-in ballistic program, a communication processor, and a power controller, and serves as an interface between the operator and the machine. Various electronic control devices such as positioning devices, gun & turret driving systems, ammunition transports, trigger devices, gun temperature sensors, and radios are interlinked to achieve automation. The AFCS uses ballistic programs and muzzle velocity sensors to calculate firing data on its own, as well as to receive shooting commands via data and voice communication from the BTCS. The FCS is the first of its kind in that it can calculate weather measurements by altitude, thus providing more precise shooting specifications.
K10 ARV (Ammunition Resupply Vehicle)
The K10 ARV is an automatic resupply vehicle based on K9 platform, sharing most of the components and characteristics. Its concept study started in November 1998 by Samsung Aerospace Industries and Pusan National University. Its designing began on 14 February 2002 by Samsung Techwin (previously Samsung Aerospace Industries), the ADD, and the DTaQ (Defense Agency for Technology and Quality), and the army declared its completion on 4 October 2005. The first vehicle rolled out on 20 November 2006, with a price tag of 2.68 billion KRW, and was assigned to the 1st Artillery Brigade of the Republic of Korea Army. South Korea became the first nation to operate such type of military equipment.
The vehicle has a combat weight of 47 metric tons, and can support a team of K9 by carrying and resupplying 104 shells of 155 mm artillery ammunition and 504 units of charges under heavy fire. The vehicle is operated by a 3 person crew, requiring only one loader by applying fully automated control system, and transfers ammunition at a maximum speed of 12 rounds/min. It takes 37 minutes to fully load, and 28 minutes to empty K10. It is often called the briquette car by military and defense industry officials.
The K10 AARV (Armored Ammunition Resupply Vehicle) is an enhanced protection variant of K10 ARV. The first of its kind will be produced in Australia as AS10.
K11 FDCV (Fire Direction Control Vehicle)
The K11 FDCV is designed for the Egyptian military to provide command & control, reconnaissance, and communication for armored vehicles. The vehicle is based on K10, and has a high mobility.
Operational history
In October 2003, the K9 Thunder was evaluated by Spain at the military base located in Zaragoza.
In 2004, the K9 was sent to Malaysia to test its operation capability in tropical rainforest environment.
In the same year, KRCMI (Korea Research Center for Measuring Instruments) developed doppler radar calibration system, which gave significant increase in accuracy by lowering the impact error from 0.1% to 0.05%. Using the new technology, the ADD and DST (Davit System Technology) launched joint project for domestic MVRS (muzzle velocity radar system). On 18 September 2007, DST announced the development of model MVRS-3000, increasing both performance and localization of the vehicle.
On 27 December 2006, South Korean military distributed K10 digital manual. The manual was developed with a budget of 1 billion KRW, and it can easily identify the equipment composition, specifications, operation procedures, operating principles, maintenance tips, and signs of failure of the K10 ARV. It also visualizes the vehicle in 3D virtual reality, so operators can easily understand compared to conventional text-based manuals. After seeing significant improvement in training efficiency, operating capability, and maintenance skill of soldiers, K9 digital manual was also adopted as a follow-up in May 2007.
In September 2010, a major issue regarding the engine was brought up by the defense committee. According to the report, a total of 38 K9 experienced engine cavitation since 2005. Initial investigation prior to the discussion suggested that the use of 3rd party manufactured antifreeze may have caused the engine cavitation; however, using the recommended TK-6-03-01012 antifreeze did not solve the problem, suggesting that the antifreeze is not the cause of the issue. One of the defense committee mentioned that the Turkish T-155, which uses identical mobile system but has APU (auxiliary power unit) installed, never reported such case. The military decided to go for further study by closely monitoring how antifreeze affects the engine, and test the APU when the vehicle is in idle. Installing APU on K9 was discussed during its development phase, but was not adapted for mass production.
The K9 Thunder saw its first combat during the bombardment of Yeonpyeong on 23 November 2010. After receiving surprise artillery bombardment from North Korea, howitzers operated by the 7th Artillery Company of the Republic of Korea Marine Corps were tasked with a counterattack. Prior to the attack, four howitzers had been on a scheduled firing exercise, and two remained in the fortified position. One vehicle experienced a shell stuck in the barrel due to a misfire from a faulty charge. After the training, the crew opened the hatches, and some dismounted while waiting for the disabled gun to be fixed. Every vehicle always carries 20 shells of HE and flare combined for rapid response. The marines on the island have been operating AN/TPQ-37 radar since mid 2010 due to increasing threats from North Korea. However, the number of radar units was not sufficient to cover the long fortified North Korean coastline that marines were facing.
Three out of four vehicles participating in the exercise received damage from initial surprise attack; shrapnel from near hit explosions damaged internal parts via open hatches, erupting fire in one vehicle by hitting the charges stored inside, but none of the vehicles suffered crew casualties. The attack also disabled main power station of the base, shutting off the radar temporarily. After relocating to a fortified position, the marines responded with three K9, including one damaged vehicle, to predesignated positions at Mudo, as they were unable to locate North Korean artillery positions. K9s were able to employ counter-battery fire only after reactivated radar detected North Korean artillery positions at Kaemori from the second wave of incoming attack. Another K9 joined the fight after switching to manual firing mode, increasing the number to four. Additional and different type of ammunitions were supplied by hand at the gun emplacements.
On 19 May 2011, the K9 performed direct firing for the first time. K9 is capable to hit bullseye at a distance of 1 km with direct firing.
On 9 February 2012, the DAPA (Defense Acquisition Program Administration) launched arms localization project, which includes K9's INS. On 18 May 2012, Doosan DST was selected for the domestic INS development. The plan to apply domestic INS on K9 was later changed to license produce in 2015 while domestic models are being used for K21 and K30.
On 10 October 2013, Daeshin Metal became the major parts supplier for Allison Transmission in making X1100-5A3 as an offset trade, further increasing localization. Applicated transmission will be equipped starting on the 10th and the 5th batch production of K9 and K10 respectively.
On 2 March 2015, South Korean military announced that Samsung Techwin is developing driver's safety system as a consequence of an accident resulting in death of an operator on 24 January. Under the safety system, the turret rotation automatically stops if the driver's hatch remains open and is at the dangerous angle to the driver. The feature can be turned off if necessary.
On 2 September 2015, another offset trade was signed between Honeywell Aerospace and Navcours. Under the agreement, Navcours will license production and service of TALIN 5000 INS, which is already being used in K9 and K55A1, for domestic use, and supply Honeywell Aerospace as well.
In May 2016, K9 test fired JBMoU (Joint Ballistics Memorandum of Understanding) compliant HE-ER ammunition in Sweden successfully, reaching 43 km in distance.
In August 2016, K9 was tested by the UAE military. The vehicle managed to drive on the desert at max speed for one hour nonstop without any malfunction.
On 18 August 2017, a K9 operated by the 5th Artillery Brigade of the Republic of Korea Army was set ablaze during a firing exercise, causing 3 deaths and 4 wounds among crew members and instructors. After the investigation, it was found that the faulty spring caused the hammer to detonate prematurely, pushing the explosion into the vehicle before the breech was fully closed, and set on fire the additional charges which were taken out from the rack for the next firing. Entire K9 operated by South Korea underwent inspection during the investigation. The Republic of Korea Armed Forces responded with installation of black box, AFSS (automatic fire suppression system), reinforced maintenance, and providing flame-resistance uniform to crew members.
In May 2018, ABC (Automatic Bore Cleaner) model RB-155 by SDI (SooSung Defense Industries) was adapted for South Korean K9. The automatic cleaner provides efficiency in maintenance by requiring just one person to clean the barrel in 20 minutes, with incomparable result compared to conventional cleaning.
The production and the delivery of the K9 Thunder ended in June 2018. The factory will continue to produce the model as K9A1 variant. The first new variant was fielded by the 5th Artillery Brigade of the Republic of Korea Army on 22 August 2018.
On 13 November 2020, the DAPA announced that entire K9 program delivered to the Republic of Korea Armed Forces is now in full operational capability, bringing the K9 Thunder program for the South Korean military to completion.
On 7 May 2021, Hanwha Defense announced cooperation with Australian company HIFraser in supplying AFSS for AS9 and AS10 for Australia. HIFraser will start to assist Korean company DNB Co in delivery of AFSS to Korean operated K9 as well.
On 29 May 2021, the K9 Vajra-T has been deployed to the Ladakh region as tensions grew between China and India in a territorial dispute.
On 7 February 2022, Hanwha Defense signed a MOU with Australian company Bisalloy Steel in supplying armor plate for AS9, AS10, and AS21 Redback to reduce manufacturing cost and strengthen partnership. Hanwha Defense plans to use armor steel from Bisalloy Steel for foreign exports including Egyptian variant while POSCO continues supplying for domestic production.
The first K9 operators conference was held at Changwon in April 2022. Militaries from Australia, Estonia, Finland, Norway, and South Korea shared knowhow and feedback, while the defense industries looked for joint R&D for future upgrades and new weapon systems.
On 14 September 2022, a K9A1 SPH and a K10 ARV demonstrated compatibility and live-fire with a variety of American munitions at Yuma Proving Ground in Arizona. The howitzer managed to fire 3 rounds in 16 seconds and 6 rounds in 43.3 seconds using the M795 projectiles. K9A1 became the first foreign platform to fire XM1113 RAP munition and achieved 53 km in shooting distance at an elevation of 900 mils.

Variants

K9A1
On 19 September 2011, the Defense Committee addressed issues regarding K9 Thunder's FCS (fire control system), noting that its computer and OS (operating system) are discontinued and outdated, thus increasing related logistics cost by 70% over past 3 years. India expressed thesame concern. The first produced 24 K9s are equipped with i386 and the rest are with i486; DOS is installed on both types. On the other hand, Samsung Techwin argued that both processor and OS are widely used in the military including newly produced weapons, that older CPUs are more durable, and that DOS has lower failure rate. However, the military determined to launch FCS upgrade program starting in 2013 for both logistics reason's and Australia's request. On 11 October 2013, the DAPA announced future plan for K9 upgrade along with new extended range ammunition starting in 2014. On 24 December, the DAPA awarded Samsung Techwin as a main provider for K9 upgrade program. On 12 August 2014, Hanwha and Poongsan are selected as preferred bidder for new extended ammunition used for both K9 and K55A1. Two companies will compete to win the project.
On 18 August 2017, the DAPA announced approval of serial production of upgraded K9. K9A1 upgrades include automatic FCS, combining GPS system to INS, improved driver's night periscope with thermal frontal camera, rear view camera, and driver's safety system. The 8~10 kW auxiliary power unit is provided by Farymann & TZEN co, Ltd. A1 standard also allows to shoot new extended range ammunition. Each vehicle will receive upgrades during its overhaul starting in 2018. The first K9A1 joined the Republic of Korea Army on 22 August 2018.
In July 2019, Hanwha was removed from new ammunition project due to unsatisfactory result, making Poongsan the sole bidder. In November 2020, new extended range ammunition by Poongsan was accepted for service after years of tests. New ammunition combines BB (base bleed) with RAP (rocket assisted propulsion), reaching 54 km with HE or 45 km with DP-ICM. The manufacturing will start in 2022, and will be operational by 2023. Poongsan is also working on different types of ammunitions such as POM (PARA - Observation Munition) and GGAM (Gliding Guided Artillery Munition) since 2013 and 2014 respectively.
Details of K9A1 upgrade:
Installation of APU : APU allows vehicle to react and fire without running the main engine, thus reduces fuel consumption. Crew members can operate without being exposed to the engine noise. Since the engine no longer needs to operate when vehicle is stationary, the cost for engine maintenance was reduced.
Enhanced driver's system : Driver's night periscope is changed from image intensifier to FLIR, and can be viewed from the monitor. Rear view camera is also installed. Driver's safety system disables turret to rotate at a certain angle when driver's hatch is open; however, the feature can be turned off if necessary.
GPS : By combining INS and GPS, the vehicle can locate itself more precisely and faster by complementing each other, which also results increase in accuracy.
Enhanced FCS : Computer and OS are upgraded, and additional software such as field manual and ammunition monitoring are installed. FCS is fully automated by using electronic fuse setter and ammunition management system. New FCS also occupies less space, and is programmed for new extended range ammunition (54 km).
K9A2
In May 2016, the DAPA announced the concept for a robotic howitzer at the international artillery conference held in the United Kingdom. The DAPA then launched several projects consisting of insensitive charge, better rifling of the main gun, and a fully automated loading system. The upgraded K9 will have longer range, faster firing rates, and reduced crew members-similar capabilities to the United States' XM2001 Crusader.
On 15 September 2020, the DAPA launched a project for indigenous engines for the vehicle. The project is expected to cost ₩75 billion over a period of 5 years. On 31 May 2021, STX Engine was selected as the winner after competing against Doosan Infracore. STX Engine will receive technology transfer and assistance from the British Ricardo plc in designing the new engine.
In August 2021, the ADD and Hanwha Defense completed the development of high-response artillery automation system started in 2016. The new system is essential for future remote controlled variant, and will enable fully automated loading system including charges and fuse set-increasing the fire rate by 1.5 times.
The Republic of Korea Armed Forces will confirm the ROC for K9A2 Block-I upgrade in March 2022. K9A2 is expected to be operational by 2027. The military is also designing K9A3 with a firing range of 100 km. The operational K9A2 technology demonstrator was revealed to public by Hanwha Defense on 21 February 2022. The vehicle's turret is extended in length for installation of autoloader. On 5 March 2022, high-response artillery automation system was shown to the public.
On 15 July 2022, Defense Acquisition Program Promotion Committee approved 2.36 trillion KRW for 2023 to 2034 in development and upgrade of K9A2 Block-I.
In September 2022 during DX Korea 2022, STX Engine presented newly designed 1,000 hp diesel engine for the K9.
Details of K9A2 upgrade:
Enhanced main gun : New rifling and chrome plating will increase barrel life from 1,000 rounds to 1,500 rounds, longer range, and allow faster firing rate.
High-response artillery automation system : Key feature of A2 and future A3 upgrade. Reduces crew number from 5 to 3 (2 in emergency) by installing fully automated autoloading system, which increases firing rate from 6 to 8 rds/min to 9 to 10 rds/min.
Increased sustain fire : All 48 rounds are located in the turret, and are accessible with the autoloader.
Turret driving system : Changes from electrohydraulic to electric driving system.
Automatic Fire Suppress System (AFSS) : Enhanced fire suppress system for crew protection.
Remote controlled weapon station (RCWS) : Enables use of secondary weapon without exposing a crew member.
Air conditioning : Increases crew comfort by cooling down the temperature.
Insensitive charge : Provides crew protection from secondary explosion due to enemy fire including heavy weapons, and required for the automatic loading process.
Composite rubber track : Provides crew comfort by reducing vibration, noise, and lesser required maintenance. Reduced weight also improves vehicle's operational range. The material has lower fatality compared to metal to surrounding soldiers when receiving attack. (?)
Enhanced armor : Anti-tank mine protection. Similar to AS9 Huntsman standard. (?)
K9A3
In 2020, the DAPA announced K9A3 upgrade plan will apply unmanned technology and achieve 100 km shooting distance using gliding ammunition. The DAPA also talked about the development of super long-range cannon and railgun to be mounted on the next generation self-propelled howitzers.
In September 2022, the ADD began research into increasing the firing range of the howitzer. The new variant is expected to equip a 58 caliber gun and ramjet munitions to achieve a maximum range greater than 80 km. The project is scheduled to be 60 months long, completing in August 2027.