The U.S. space agency has a language all its own. NASA uses so many acronyms that the agency issues a book to its employees to keep track of them. And even when NASA uses ordinary words, they're often imbued with special meaning, generally designed to take the edge off graphic situations. "When you're inside," says one NASA spokesman, "it's not a problem understanding what we're talking about." It's the rest of us who need some help. Here are our translations of NASA's favorite lingo.