COLD REGIONS TEST CENTER, Alaska- Soldiers depend on self-propelled howitzers for mobility and punishing firepower in combat situations.

This past winter, a high impact, multi-month evaluation at U.S. Army Cold Regions Test Center helped ensure the latest generation of self-propelled howitzers works even in the world's coldest environments. The Paladin Integrated Management (PIM) evaluation is a massive effort verifying the effectiveness of a host of improvements to the venerable M109 Paladin self-propelled howitzer, the most common platform of its kind in the world.

With a wider stance than its predecessor, the M109A7 variant is more stable and adept at absorbing the howitzer's powerful recoil as it fires. Beneath the armor, a new engine identical to that found in the Bradley Fighting Vehicle puts out nearly 200 more horsepower than the power plant in the last version of the Paladin. The engine delivers power to the tracks via a transmission that also comes to the platform from the Bradley, an interchangeability of components that helps mechanics. The platform's stowage capacity for artillery shells has been increased and sophisticated digital communications, fire control, and navigation systems have been improved. While previous incarnations of the Paladin used a hydraulic system to operate such components as the cab and ammunition rammer, the PIM uses a generator that pushes out a whopping 70 kilowatts of electricity, enough power to run an entire 40 house neighborhood block.

Though the weather this past winter at CRTC didn't reach the jaw-dropping temperatures of -50 degrees Fahrenheit or more below zero that are typical, the variation didn't faze the testers.

"Early on we knew it was going to be a relatively warm winter, but it was determined we would still get worthwhile data," said Elizabeth Palm, test officer. "We can't control the weather, but we can adjust to it to take advantage of the coldest times."

The coldest times still saw the mercury plunge below -25 degrees Fahrenheit, and Palm and the crew had much to do. The PIM accumulated hundreds of miles on CRTC's punishing road courses, and undertook braking and acceleration tests at CRTC's automotive test track. Throughout the course of the evaluation, CRTC testers fired hundreds of rounds from the howitzer's 155mm cannon at multiple angles and with varying propelling charges. The firing tests were not gentle, but simulated the kind of rapid firing that Soldiers in combat depend on for survival.

Further, the engine was subjected to cold starts in temperatures well below zero, oftentimes after having cold air blown on its engine from tubular fans to ensure a maximum of frigidness.

"The convective flow assists in cooling the component fluid temperatures more quickly than cold soaking alone," explained Palm.

For the testing at CRTC, skilled mechanics from Yuma, Az., capable of rapidly repairing both the Bradley and M109A7 , spent weeks supporting the test in Alaska, as did vehicle operators whose previous experience on the vehicle was gained in the desert southwest. All told, more than 25 individuals traveled from Yuma to the frigid interior Alaska winter to support the test. Likewise, Palm spent five months in Yuma last summer assisting with testing of the system in the extreme heat, and felt the experience was useful.

"I liked working on the system there and knowing what was coming up," she said. "That made the test a lot easier."

The test was in progress during a site visit from Army Test and Evaluation Command commander Maj. Gen. Daniel Karbler, who saw firsthand the critical importance of natural environment testing.

"It's almost impossible to drive something in a conditioning chamber," he said. "You can certainly chill it down to a certain temperature, but that's about the extent of it. When you want to put it in operation, put loads on it, and use it in the whole of the environment, it is totally different. A cold chamber has a place in initial testing, but once you put something into operation, you have to take it out into the environment."