The USA’s 155mm M109 self-propelled howitzers (SPH) were first introduced in 1962, as a form of armored mobile artillery that could stand up to the massed fire tactics of Soviet heavy artillery and rockets. They and their companion M992 Armored Ammunition Resupply Vehicles (AARV) have been rebuilt and upgraded several times, most recently via the M109A6 Paladin upgrade.
In the meantime, the Army has re-learned a few home truths. Artillery arrives in seconds rather than minutes or hours, is never unavailable due to bad weather, and cheaply delivers a volume of explosive destruction that would otherwise require hundreds of millions of dollars worth of bombers and precision weapons. Most combat casualties in the gunpowder age have come from artillery fire, and the US Army will need its mobile fleet for some time to come. So, too, will the many countries that have bought the M109 and still use it, unless BAE wishes to cede that market to South Korea’s modern K9/K10 system, or new concept candidates like the KMW/GDLS DONAR. What to do? Enter the Paladin PIM program.