Experts Question Usefulness of Air Force's Robotic X-37B Space Plane

New observations of the Air Force

U.S. Military Space Plane Begins a Fourth (Mostly) Secret Mission - The New York Times

DARPA scraps XS-1 military space plane project after Boeing drops out

What Did the U.S. Just Put in Orbit? - FLYING Magazine

What's the X-37 Doing Up There?, Air & Space Magazine

Why the Russian Space Plane Won't Fly

US Air Force's Secretive X-37B Space Plane Nears Day 500 in Orbit

Apart from their unmanned capabilities and smaller overall size, what are the differences between the legacy space shuttle and the new X-37B space plane? - Quora

Up in the sky, a mystery space plane -- but why?

Preparations underway for first landing of X-37B > Air Force > Article Display

How autonomous wingmen will help fighter pilots in the next war

The X-37B and four more secret crafts from Boeing's mysterious Phantom Works - Discovery

A China-US war in space: The after-action report - Bulletin of the Atomic Scientists

Boeing's X-37B Military Space Plane Spends Record 908 Days in Orbit

Air Force gives a rare look at the research going to orbit in its X-37B spaceplane