ATMOS (Autonomous Truck Mounted howitzer System 2000) is a 155 mm/52 calibre self-propelled gun system manufactured by Israeli military manufacturer Soltam Systems (Elbit Systems). The ATMOS 2000 is a hybrid of the TATRA T815 VVN 6X6 wheeled Truck chassis, with Soltam made 155 mm 45/52 Cal Long-Range Gun (ATHOS) that is equipped with the most modern c3 system including on board computation, Inertial Navigation & Aiming Systems, and easy ammunition handling system. The system is long range, fast moving, truck mounted with a high firepower and mobility, rapid deployment, short response time, operable in all terrain areas.
While firing, the ATMOS 2000 is supported by rear spades. Firing loads are transferred directly to the ground, without harming the vehicle chassis. The buffer is a cylinder hydraulic with a hydro-pneumatic recuperator. Weapon elevation and traverse are all hydraulic and computer controlled. The gun’s aiming gears, load assist systems and spades are operated by a hydraulic power pack. With a 155 mm/52 barrel, a 41 km maximum range can be achieved, using Extended Range Full-Bore – Base Bleed (ERFB-BB) projectile, 30 km firing the NATO L15 High Explosive (HE) projectile and 24.5 km firing the older M107 HE projectile.
The ATMOS carries 32 projectiles and propelling charges, as well as the Guns crewmembers, their equipment and all the logistics. ATMOS is normally operated by a crew of four, of whom two are loaders positioned one either side at the rear. A rate of fire of between 4 and 9 rds/min are claimed and to reduce crew fatigue, a flick rammer is fitted as standard. To provide a more stable firing platform, two large spades are lowered to the ground one either side at the rear of the system by remote hydraulic control. The artillery systems are equipped with fire control computers (FCC), muzzle velocity radar (MVR), an inertial navigation system (INS) and a target acquisition system (TAS).
Although the prototype system is installed on a modified TATRA T815 VVN 6X6 wheeled Truck chassis, Elbit Systems have emphasised that it could be fitted to a wider range of other tracked and wheeled chassis. For the export market, Soltam Systems is currently marketing ATMOS with 155 mm 39, 45 and 52 calibre barrels. The forward-control armour-protected cab provides the occupants with protection from small arms fire and shell splinters. It is envisioned that production versions of the ATMOS would be fully air-portable in a Lockheed Martin C-130 Hercules transport aircraft.