The U.S. Marine Corps has decided its Legged Squad Support System, or LS3, also known as the "robotic mule," is too loud to use on the battlefield.

The Marines began testing the robotic mule in a series of training events in September, although officials at the Defense Advanced Research Projects Agency said the gas-powered quadruped would likely never see actual combat.

The robot was used to carry equipment, lightening the load for troops on the field. Testing events included simulations in forests, open fields and urban environments, where the robot was able to carry over 400 pounds of equipment.

While the project has received praise from testers and participants, officials ultimately decided the robot was too loud, and could pose danger to Marines by giving away their position to the enemy.

"As Marines were using it, there was the challenge of seeing the potential possibility because of the limitations of the robot itself," Marine Corps Warfighting Lab spokesman told Military.com. "They took it as it was: a loud robot that's going to give away their position."

Aside from the noise, testers faced additional challenges, including repairing the device and attempting to integrate it into a Marine patrol unit.

A second, smaller robotic quadruped, dubbed Spot, produced less noise, however the adjustments resulted in a much lower carrying capacity.

The LS3 mule and Spot were the result of a $32 million contract signed between DARPA and Boston Dynamics, a subsidiary of Google, in 2010. An additional $10 million contract followed to support testing with the Marine Corps.