ENCORE  The military is a dangerous calling.  But technology can help out, so researchers are constantly trying to make soldiers safer.  Writer Mary Roach investigates how scientists studying so-called human factors are protecting troops from such aggressive foes as heat, noise, and fatigue.  She also learns how bad odors were once considered a secret weapon. And while soldiers have long used camouflage to help them blend in, insects may be the original masters of disguise.  A discovery in fossilized amber shows that a variety of bugs employed D.I.Y. camouflaging tricks 100 million years ago. But where is the defense race headed?  The top-secret branch of the Pentagon whose job is to make tomorrow happen today has some ideas.  A reporter shares DARPA’s plan for augmented super-soldiers. Plus, do we always need a technological boost to stay safe?  Find out how your innate chemical defense system protects you.  It’s an adrenaline rush! Guests: Mary Roach  - Science reporter, author of “Grunt: The Curious Science of Humans at War” Michael Engel – Entomologist, invertebrate paleontologist, University of Kansas, and senior curator of its Natural History Museum Annie Jacobsen – Journalist, author of The Pentagon’s Brain: An Uncensored History of DARPA, America’s Top-Secret Military Research Agency Brian Hoffman – Professor of medicine, Harvard Medical School, author of Adrenaline