WASHINGTON (CNN) -- For years, top Marine commanders have been worried about the amount of weight each of their troops carries.
There's the body armor, weapons and ammunition. Those are must-haves. But they also carry lots of water to keep from becoming dehydrated and batteries for their radios, GPS gear and night-vision goggles.
Now, the Marine Corps is looking at how to reduce the water and battery weight.
At a base in California this month, Marine and Navy researchers are testing a concept called Marine Austere Patrolling System, with a built-in solar panel and a water filtration system.
This isn't about the Marine Corps suddenly joining the "green" movement. It's about weight and safety.
The idea of the solar panel is that Marines would charge their gear with sunlight. The solar panel weighs only 13 pounds and can be used repeatedly. Without MAPS, a Marine on a four-day mission may need 100 pounds of batteries.
"MAPS doesn't replace the need for battery power storage," said Peter Vietti, a spokesman for the Office of Naval Research; it allows the Marine to carry fewer batteries on each mission.
The solar panel charges and recharges a central battery whenever the sun is out. Then, when the Marine needs power, even at night, the battery provides it.
The water-filtration part of MAPS also addresses the weight issue. Each gallon of water a Marine carries weighs more than 8 pounds. And they may need two or more gallons for that four-day tour.
The Marine can take water from a local river, maybe a village well, and run it through the filter to make it safe to drink.
But weight isn't the only problem that MAPS addresses.
If a Marine unit does need to be resupplied with water and/or batteries, the supplies have to be carried in by helicopter or truck.
And those supply units are vulnerable to attack. So, fewer resupply missions means fewer Marines doing the resupplying or putting themselves at risk.
Capt. Frank Furman told National Defense magazine that the water component of MAPS could be used by Marines around the world in five years.
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