AS-90

Information was found on Wikipedia.

The **AS-90** ("Artillery System for the 1990s"), known officially as **Gun Equipment 155 mm L131**, is an armored self-propelled artillery weapon used by the British Army.

## History

AS-90 was designed and built by the Armaments division of Vickers Shipbuilding and Engineering (VSEL), whose parent company became BAE Systems in 1999. VSEL provided 179 vehicles between 1992 and 1995 at a cost of £300 million ($480 million). The AS-90 was first deployed by the British Army in 1993. The AS-90s were acquired to re-equip six of the eight self-propelled field artillery regiments (each of 24 guns) in the I (BR) Corps, replacing the 105 mm FV433 Abbot SPG and older M109 155 mm Self Propelled Gun and FH70 towed howitzer.

In 1999, Marconi Electronic Systems was contracted to upgrade British Army AS-90s to include a 52 caliber gun in order to increase the range of the artillery. Critical to the program was a bi-modular charge system from Somchem of South Africa (selected after extensive trials of ammunition from many suppliers), which offered greatly reduced barrel wear. However, this ammunition failed to meet the requirement for insensitive munitions and the project was terminated.

It remains in UK service and will equip three field regiments supporting armored infantry brigades for the foreseeable future. In 2008 there were 134 AS-90s in service, reduced to 117 in 2015. The AS-90 underwent a capability enhancement programmed in 2008 and 2009, primarily relating to upgrades of the AS-90's electronic system.

The initial expected out-of-service date for the AS-90 was 2030, but this was later delayed to 2032, with a replacement planned to enter service in 2029.

On 24 April 2022, it was reported that AS-90s and 45,000 artillery rounds will be sent to Ukraine, but this was denied on 25 April by Defense Secretary Ben Wallace.

## Development

AS-90 started in the mid-1980s as a private venture on the gamble that the tri-national SP70 would fail. When this subsequently occurred, the Ministry of Defense (MoD) issued a cardinal point specification on one page for a new 155 mm self-propelled gun. The MoD was also required to consider the US "Paladin", an upgraded M109 howitzer. The MoD undertook studies in 2006–09 to "up-gun" the Royal Navy's main shipboard gun armament, the 4.5 inch Mark 8 naval gun, to accept 155 mm ammunition from the AS-90. This would have introduced a common gun caliber for the British Army and Royal Navy, helping with ammunition logistics, and encouraging joint Army-Navy development of extended-range and precision-guided shells. The Royal Navy did not adopt this gun system.

## Design

In 1963 certain NATO nations, including the UK, agreed to a "Ballistics Memorandum of Understanding" for a 155 mm 39 caliber ordnance and a baseline projectile with the shape used for the US M549 rocket-assisted shell. The AS-90 uses a conforming 39 caliber barrel which fires the L15 unassisted projectile out to a range of 24.7 km. However, this was a new design of ordnance using a split sliding block breech with Crossley obturation, instead of the more usual screw breech, to permit bagged charges (no metal cartridge cases). The breech mechanism has a primer magazine holding 18 primers. The standard ammunition is designed for FH-70 (L15 HE and associated propelling charges) although in training the less effective but cheaper M107 with Green and White propelling charges is used.

It is fitted with an auxiliary power unit to eliminate the need to run the main engine to keep the batteries charged while stationary; electrical servos drive the automated elevation, traverse, magazine, shell transfer arm, and loader as well as power for electronics and communications.

The vehicle is fitted with an autonomous navigation and gun laying dynamic reference unit (DRU) mounted on the trunnion. All main turret functions are controlled by a Turret Control Computer (TCC) with control and display units for No 1 (Detachment Commander), No 2 (loader), and No 3 (layer). The combination of the DRU, TCC, and powered laying controls provides auto laying. Every gun is fitted with a radar Muzzle Velocity Measuring Device. Reversionary mode laying uses deflection laying via the direct fire sight.

The gun can be brought into action fully closed down; the barrel can be clamped and unclamped from within the vehicle. In-to and out-of-action times are less than 1 minute.

## Specifications

* Crew: 5, on board when moving (driver plus 4 gun detachments), full gun detachment 10 including the driver, 4 detachment members in the turret.
* Length: 9.07 m
* Width: 3.3 m
* Height: 3.0 m
* Armor: 17 mm (maximum, steel)
* Weight: 45 tons[*vague*]
* Caliber: 155 mm
* Range: 25 km (39 Cal), 30 km (52 Cal) standard charges
* Rate of fire: 3 rounds in 10 seconds (burst), 6 rounds per minute for 3 minutes (intense), 2 rounds per minute for 60 minutes (sustained)
* Secondary armament: 7.62 mm L7 GPMG
* Ammunition carried: 48 projectiles and charges (31 turret and 17 hull), 1000 MG rounds
* Main engine: Cummins VTA903T 660 bhp 90 degree V8, 4 stroke, liquid cooled, turbo diesel
* Max speed: 55 km/h (Road)
* Range: 370 km or 231 mi (Road)
* Ground clearance: 0.41 m; Gradient: 60°; Vertical obstacle: 0.75 m; Trench crossing: 2.8 m; Fording depth: 1.5 m

## Variants

**AS-90D** – Modified for desert use. Thermal protection for crew and extra cooling for engine and machinery. Tracks adapted for reduced wear in sandy conditions.

**AS-90 "Braveheart"** – Basically the AS-90, but fitted with the 52 caliber length gun. This project was terminated due to non-compliant propellant charges.[*citation needed*]

**Armatohaubica "Krab"** – (Eng. *Cannon-howitzer Crab*) Licensed "Braveheart" turret on a K9 Thunder chassis, with modern "Azalia" BMS. Designed and integrated in Poland, by Huta Stalowa Wola and WB Electronics. Two Krab ("Crab") prototypes were built in 2001 and successfully completed all required evaluations and state acceptance trials. Initial serial production started in 2008, with eight units delivered to Polish Land Forces for testing. In 2014 production of Krab chassis was forwarded to Korean Samsung Techwin, which will provide 120 units, replacing Polish build UPG chassis in serial vehicles.

## Operators

United Kingdom

* British Army – Royal Artillery
	+ 1st Regiment Royal Horse Artillery.
	+ 19th Regiment Royal Artillery.