X-47B: the Navy's UFO-like stealth drone passes a milestone

May 6, 2013: The Northrop Grumman-built X-47B Unmanned Combat Air System (UCAS) demonstrator completed its first shore-based arrested landing at Naval Air Station Patuxent River, Md. The landing begins the final phase of testing prior to carrier-based trials planned for later this month. (Northrop Grumman)

Nov. 29, 2012: In preparation for the first catapult launch of the U.S. Navy's X-47B unmanned aircraft, a flight deck director -- aka "yellow shirt" -- and a deck operator using Northrop Grumman's wireless, handheld Control Display Unit guide the aircraft into position on a shore-based catapult at Naval Air Station Patuxent River, Md. <a href="http://www.foxnews.com/tech/2012/11/29/navy-catapults-unmanned-aircraft-for-first-time/">Read more</a> (Northrop Grumman Corp)

March 4, 2011: The third flight of X-47B AV-1, from Edwards Air Force Base. (Northrop Grumman Corp.)

The existence of two X-47B enables Northrop Grumman to conduct faster and more productive flight tests. (Northrop Grumman Corp.)

Oct. 11, 2011: The U.S. Navy passed a first milestone for its futuristic new stealth drone when it successfully retracted its landing gear and flew in cruise configuration for the first time. <a href="http://www.foxnews.com/tech/2011/10/11/us-navys-ufo-like-stealth-drone-reaches-new-milestone/">Read more</a> (Northrop Grumman)

The craft's first flight in cruise configuration provided an important measure of its maturity and readiness to begin the next phase of flight testing. (Northrop Grumman Corp.)

An early version of the X-47B, seen in 2010 on the runway in Palmdale, Calif. (Northrop Grumman Corp.)

(Northrop Grumman)