|Place of origin||South Korea|
|In service||K9: 1999–present|
|Used by||See Operators|
|Wars||Bombardment of Yeonpyeong|
|Designer||Agency for Defense Development|
Samsung Aerospace Industries
|Manufacturer||Samsung Aerospace Industries (1999-2000)|
Samsung Techwin (2000-2015)
Hanwha Techwin (2015-2017)
Hanwha Land Systems (2017-2019)
Hanwha Defense (current)
Larsen and Toubro (Current)
|Unit cost||$3.6 million|
|Crew||5 (Commander, Driver, Gunner, 2 Loaders)|
|Maximum firing range||18 km (M107, HE)|
30 km (M549A1, HE-RAP)
36 km (K310, BB/DP-ICM)
40 km (K307, BB/HE)
52 km (K315, HE-RAP)
100+ km (GGAM, in development)
|Hyundai WIA CN98 155 mm 52 caliber|
|12.7 mm (.50 caliber) K6 HMG|
|Engine||MTU Friedrichshafen MT 881 Ka-500 8-cylinder water-cooled diesel engine|
|Transmission||S&T Dynamics X1100-5A3|
|Maximum speed||67 km/h|
The K9 Thunder is a South Korean self-propelled 155 mm howitzer designed and developed by the Agency for Defense Development 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 standard, and a further development of a K9A2 variant is in process.
In 1980s, the ROK Armed Forces came in need of new artillery system to contest North Korean equipment. The armed forces operated M107 self-propelled gun and K55 self-propelled howitzer; however, they had shorter firing range compared to M-1978 Koksan and were outnumbered by various North Korean artillery. With the success of designing and manufacturing KH-178 and KH-179 towed artillery, and experience gained by license producing K55 (KM109A2), the Ministry of Defense ordered to develop new system that has 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).
The ADD first offered upgrades on existing K55, inspired by the United States' M109 Howitzer Improvement Program (HIP), but was rejected by the Republic of Korea Army. As a result, the ADD determined to create new weapon system and worked on conceptual model till 1991. Early concept requested by the military includes river crossing capability and installation of M61 Vulcan as anti-air weapon, which were removed due to unnecessity for such long-range weapon.
In 1992, the Ground System Division of United Defense LP (now BAE Systems Land and Armaments) invited members of the ADD for its first M109A6 Paladin release ceremony and expressed interest in participating Korea's self-propelled howitzer program by upgrading K55 to Paladin standard, which was rejected by South Korea.
By late 1990s, internal review showed localization of 107 out of 235 (45.5%) technologies required to build the artillery. After the review, South Korea decided to continue developing domestic main system, main gun, 155 mm ammunition, fire control system, structure, and autoloader. On the other hand, engine, transmission, and INS were chosen to be imported from foreign partners, and license produce hydropneumatic suspension to boost up localization by 70%. The engineers faced biggest challenge on 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.
The turret servo electrohydraulic system is a derive from that of K1 MBT. Automatic fire control system enabled rapid aiming, faster shooting, and improvement to accuracy. Originally, Air-Log hydropneumatic suspension, which was being used for British AS-90, was chosen for test for license produce, but failed to absorb shock from much bigger 52 caliber gun. Later, South Korea developed domestic hydropneumatic suspension and sold to Britain.
A total of two prototypes were built and performed first open trial in 1996. During the test, the prototypes succeeded to fire distance of 40 km and 6 rounds per minutes but failed to fire three rounds in 15 seconds. On 5 December 1997, one of prototypes was damaged by fire after testing 18 rounds in 3 minutes due to failing complete combustion, which resulted death of one researcher among three wounded. However, damaged prototype's internal system survived the fire, thus was repaired for further use. Two prototypes fired a total of 4,100 rounds and underwent 13,800 km driving test including in extreme temperature conditions. The localization rate reached 87% by the end of the development.
The contract for the K9 artillery system was awarded to Samsung Aerospace Industries on 22 December 1998. The first vehicle was rolled out on 17 December 1999, and was fielded to the Republic of Korea Marine Corps in Yeonpyeong Island. On 13 November 2020, DAPA announced that deliveries of the K9 had been completed; since 1999, an estimated 1,300 K9 SPHs were handed over to the ROK military.
On December 2020, the Agency for Defense Development commenced a study to create unmanned variants of the K9 Thunder and K1 88-Tank. The study is expected to be completed by November 2024. Hanwha Defense is in charge of developing the unmanned self-propelled artillery and is expected to fully produce an autonomous K9 Thunder by 2040 after the K9A2 variant.
Prior to the battle, the howitzers returned from a scheduled firing exercise, using most of the shells stored within the howitzer. In addition, one howitzer experienced a problem during the exercise when a shell became stuck in the barrel, disabling it. Two units received slight damage to their firing control systems during the initial North Korean attack, meaning only three out of the six units were able to counterattack. Eventually, the howitzer that had barrel problems joined the second counterattack after receiving field repairs. The K9s fired only one shell every 1.5 minutes, because the marines had to carry the shells from the armory and manually load the howitzer under heavy fire after exhausting B/L rounds.
K9 is an indigenous system of an all-welded steel armour construction which is rated to withstand 14.5 mm armour piercing rounds, 152 mm shell fragments, and anti-personnel mines. The main armament consists of a 155 mm/52 calibre ordnance with a maximum firing range of 40 km; the K307 BB-HE projectile propelled by the K676 top charge has a muzzle velocity of 928 m/s (3,040 ft/s). State-of-the-art mobility subsystems include a 1,000 horsepower (750 kW) engine with potential for growth and hydropneumatic suspension unit, a requirement for Korea's rugged mountainous terrain. K9 is capable of various maneuvers, including high-speed driving and sudden stops.
It was designed to give the artillery arm of the Republic of Korea Army a significant improvement in capability. With a claimed range of 75 km, it offers greater mobility, longer range, higher rate of fire, and increased battlefield survivability, as it can quickly be brought into action, open fire, and come out of action. It is less likely to be engaged by counter-battery fire, by relying on shoot-and-scoot. The unit also supports full CBRN protection.
In June 2016, the Defense Acquisition Program Administration (DAPA) revealed they were designing a new fully automatic projectile-and-charge loading system that will be retrofitted to the K9, essentially giving it a robotic turret. The purpose is to reduce the crew needed to operate the vehicle to two in order to mitigate personnel losses expected to be suffered during North Korean attacks.
The K9 has the ability to fire its shells in MRSI mode (Multiple Rounds Simultaneous Impact). In the MRSI mode, the K9 is able to fire three shells in under 15 seconds—1 shell every 5 seconds—each in different trajectories so that all of the shells will arrive on their target at the same time.
K10 Ammunition Resupply Vehicle (ARV)
The K10 is an automatic ammunition resupply vehicle built on the K9 platform, part of the K9 Thunder system. It shares the same chassis as K9, preserving K9's mobility, and can follow the main artillery battery without lagging behind. Maximum transfer rate of shells is 12 rounds per minute, and maximum load of shells is 104 rounds.
The reloading process is fully automated. The reloading is done through a munition bridge on the K10 that extends out to lock itself into a reception hole located at the rear of the K9. This allows the unit to rearm itself under harsh combat conditions without the crew having to expose themselves to the combat environment.
With technical support from ADD and Samsung Aerospace Industries, Turkey started designing the structure of its self-propelled howitzer based on the K9 in 1999. On 4 May 2000, the Ministry of National Defense of the Republic of Korea and Turkish Land Forces Command signed a memorandum of understanding (MOU) to supply K9 subsystems till 2011. A formal contract was signed by Samsung Techwin (formerly Samsung Aerospace Industries) and the Embassy of the Republic of Turkey in Seoul on 20 July 2001 worth an initial amount of $60 million—a total deal of $1 billion, including technology transfer and license to produce, for 350 vehicles through 2011. The Turkish variant self-propelled howitzer was named T-155 Firtina and to be assembled in Turkey.
The K9 was a contender for Phase 1C of Australia's Land 17 Artillery Replacement Program prior to that phase of the project being cancelled in May 2012.
On 14 May 2019, in the lead-up to the 2019 Federal Election, the Prime Minister of Australia, Scott Morrison, announced that 30 K9 howitzers and associated support equipment, including ten K10 ammunition resupply vehicles, would be acquired for the ADF. No time frame has been given for the purchase.
On 3 September 2020, the Minister for Defence, Linda Reynolds, announced a request for tender to locally build 30 K9s under the Land 8116 Phase 1 Protected Mobility Fires requirement. The sole-source request for tender will be released to the preferred supplier, Hanwha Defence Australia, to build and maintain 30 K9s and 15 K10s, as well as their supporting systems. These will be built at Hanwha Australia's Geelong facility. The total system (K9, K10 and the Kongsberg Fire Control System) will be known in Australia as the AS9 Huntsman. 
Hanwha Techwin joined hand with Indian conglomerate Larsen and Toubro Limited to supply 100 K9-T guns (known in India as K-9 Vajra) for the Indian Army Howitzer competition.K9 Thunder overcame a sand storm to successfully become a part of the Indian Military.
In September 2015, Larsen and Toubro emerged as the finalist for a US$800 million contract to supply 100 self-propelled howitzers to the Indian Army. The vehicle is the K9 VAJRA-T, a variant of the K9 specially designed for operation in the desert areas. By January 2020, more than half of K-9 Vajra guns had already been delivered to the Indian army ahead of schedule.
In July 2016, the Finnish Ministry of Defence announced that an undisclosed number of used K9s have been selected to be acquired from the Republic of Korea. The acquisition is claimed to be biggest of the decade for the Land Forces, whose both mobile and towed artillery face mass outdating in the 2020s. In February 2017, the Ministry of Defence announced that Finland will acquire 48 used K9s over a period of seven years starting in 2018, with conscript training on the equipment commencing in 2019.
Estonia has also confirmed its decision to purchase K9 Thunders. According to other sources, Estonia is teaming up with Finland in the procurement of the K9, and will order 12 howitzers. At the end of June 2018 Rauno Sirk, the director of the Estonian military procurement agency, said in a statement that Estonia will buy K9 Thunder howitzers, the first of the twelve will arrive in the country in 2020. 
On 24 August 2016 the Norwegian Defence Materiel Agency published their intention to continue negotiations with Hanwha Techwin and Swiss RUAG, which has offered their M109 "KAWEST" upgrade. At the same time, the NDMA said that negotiations concerning the KMW-made Panzerhaubitze 2000 and the Nexter Caesar had been put "on hold". Unnamed sources in the Norwegian Army had previously stated that the K9 was a leading candidate in the competition.
On 20 December 2017, a contract was signed between Hanwha Land Systems and Norwegian Defence Materiel Agency for ₩245.2 billion to supply 24 K9 Thunder and 6 K10 ARV by 2020. K9 outperformed competitors in various weather and terrain conditions according to Norwegian military officials during trials.
Norwegian variant was named as K9 VIDAR (Versatile InDirect ARtillery system), and is based on K9 PIP configuration. It uses Norwegian ODIN fire support system and radio communication systems, and spall liner is added on armor package to increase protection.
In April 2017, it was reported that Hanwha Techwin was in negotiations with Egypt to export its K9 Thunder self-propelled howitzer. The K9 Thunder is one of the contenders for supplying Egypt with new artillery systems, other howitzers competing with the K9 include those from Russia, South Africa and France, specifically the CAESAR self-propelled howitzer. South Korea's K9 self-propelled howitzer began performance evaluation tests in Egypt at the end of July 2017. A K9 howitzer arrived in Egypt earlier that month for test-firing at a range located west of Cairo. Egypt plans to complete performance evaluations of the howitzer by the end of the year and sign a contract in early 2018.
Variants and upgrades
- XK9: Experimental prototype.
- K9 Thunder: First-production variant.
- AS9 "Aussie Thunder": Offered Australian variant of the K9 in 2012.
- K9 VAJRA-T (Lightning): Indian variant of the K9. Manufactured by Larsen & Toubro under license, consisting 50% component (by value) including 14 major sub-systems developed by Indian companies. It has been customised as per desert conditions.
- K9FIN Moukari (Sledge-hammer): Finnish variant of the K9. Formerly used by the Republic of Korea Armed Forces, and refurbished with upgrades including APU.
- K9A1: First enhanced variant. Added APU, GPS navigator, driver's thermal periscope, rear surveillance camera, and improved fire control system. A1 upgrade also allows to use new extended range ammunition, increasing its firing range. First K9A1 rolled out and is in service of the Republic of Korea Army since 2018. All K-9 operated by the ROK Armed Forces will be upgraded to A1 by 2030.
- K9 VIDAR (Versatile InDirect ARtillery system): Norwegian variant of the K9A1.
- AS9 "Huntsman": Offered Australian variant of the K9 in 2019 inline with Hanhwa's proposal of the AS21 "Redback" IFV offering for LAND 400 Phase 3.
- K9A2: Under development. A2 variant will apply auto-loader, increased firing rate, 3 operators, remote control directly from BTCS.
- K10: Ammunition resupply vehicle using the K9 chassis.
- K10 VIDAR (Versatile InDirect ARtillery system): Norwegian variant of the K10.
- AS10: Offered Australian variant of the K10.
- T-155 Fırtına: Turkish version with modified turret, chassis, electronics and navigation system.
- AHS Krab: Polish self-propelled howitzer, using the K9 chassis and AS-90 turret.
Hanwha Defence Australia has been named the sole preferred bidder for the procurement of 30 K9 'Huntsman' self-propelled howitzers and 15 K10 armoured ammunition resupply vehicles. 
On 26 June 2018, Estonia signed an agreement with South Korea for the procurement of 12 K9 self-propelled howitzers, with a reported option for 12 additional artillery systems. The agreement also includes training, maintenance and spare parts. Deliveries to start in 2020. The purchase of an additional 6 howitzers was announced in October 2019.
10 units were bought from South Korea and assembled by L&T in India and were handed over to the Indian Army during Defexpo 2018. Remainder of the 100 were produced by Larsen & Toubro for the Indian Army as K-9 VAJRA T. As of February 2021, all 100 units have been delivered. On May 29, 2021, the K9 Vajra has been deployed to the Ladakh region.
Norway has selected the K9 Thunder in its bid to replace the M109A3GNM SPHs that have been in service since the 1960s. 24 K9 and 6 K10 have been purchased, with an option for another 24 K9 and additional K10. Deliveries are scheduled to begin in 2019.
Total production of 1,178 K9s and 179 K10s were fielded by 2019. Last 74 K9s in between 2018 and 2019 were built as K9A1 configuration. All K9 will be upgraded to K9A1 by 2030, and K9A2 variant development is ongoing.
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