Covert military operations and space shuttle missions are both burdened by the fact that they rely on an inefficient, energy-wasting machine: the human body. Considering one of the biggest logistical problems planners face is getting power to equipment in remote places like Afghanistan or the moon, researchers are devoting their efforts to cut some of those losses through “energy harvesting” from the human body. If that gives you creepy images of people wired up as batteries a la “The Matrix,” stop fretting. What NASA and the Pentagon want to do is scoop up electrons from what bodies in normal activity produce: heat, motion, flexing and stretching, compression, urine, and body heat. This is quite different from other human-powered schemes that take extra exertion, like spring or dynamo flashlights and radios that are wound-up by a special handle, flashlights that are squeezed by the user to generate charge, or flywheels that store energy from a cord that is pulled.