How to Pack a Robot Mule

The LS3 is made for war zones, but it is not viewed as a weapon. It's a mule—though some Marines would like to see a little more. "We'd love a machine gun on it," says 1st Lt. Alex Hurran.

The military needs a robotic mule because tracked and wheeled vehicles can't go where dismounted Marines do—a machine needs legs to traverse rocks, steep inclines, woods, and swamps. The idea behind the LS3 concept is for dismounted Marines to call on the robot mules to bring supplies to their secured positions. The U.S. military currently uses mules and horses for this purpose—often enough that they have experts at picking, packing, and caring for them. Two mule experts from the Mountain Warfare Training Center in California have come to the Massachusetts test to help Marines load the LS3 most efficiently. The experts, Gunnery Sgt. Andrew Balcunas and animal packing program director Anthony Parkhurst, gather around one of the LS3s and discuss the most resilient buckles and toughest straps.

Mules can carry one-third of their body weight, and they can weigh as much as the 1200-pound robot. LS3 has a similar cargo capacity: about 400 pounds of gear, or about one-third of its weight. However, the experts load it down with only 250 pounds of ammunition cans and boxes of prepackaged food. "If we were loading slabs of lead, we'd have gotten to 400," Parkhurst says. "But we're packing things Marines would carry."

For one thing, LS3 still has kinks to work out. The prototype's exhaust is as hot as an automobile's, which limits the amount of room available for packing. Future versions will have shells and possibly sidecars that will give the robot more usable space. It will also become easier to balance loads on the mechanical mule. "Eventually, we'll have a tool that will say it's too heavy on one side," says Boston Dynamics' Joe Bondaryk, the company's project manager of the LS3 program.

Marines appreciate this approach—every pound the robots carry is one a Marine doesn't have to put in a backpack. To that end, the Marines of the 1/5 also see the LS3 being used to bring wounded Marines away from firefights. It takes six Marines to carry one injured Marine, and anything that lessens that load will be eagerly accepted in war zones. First, Boston Dynamics will have to streamline the LS3, though. The best place to carry a wounded soldier would be on top of the robot, but currently that's where the hot exhaust is expelled. Litters on either side could be the answer, if that weight is counterbalanced on the opposite side.