Legged squad support system (LS3) prototype during testing. This semi-autonomous robot is able to move through rugged terrain carrying loads of up to 180 kilograms that would otherwise have to be carried by soldiers. It has sensors that allow it to automatically follow a leader, or negotiate obstacles to a designated location. Sensors are also planned to allow the LS3 to respond to spoken commands. It can walk 32 kilometres in 24 hours without being refuelled and can also a act as an auxiliary power supply. The LS3 is being developed by Boston Dynamics and the Defense Advanced Research Projects Agency (DARPA).