The Air Force is to launch the first test flight of the X-37 pilotless space plane Wednesday. It's meant to stay aloft for months, but its mission is secret, leading some to worry about its purpose.
The head of the Missile Defense Agency suggests the plans could be altered, echoing President Obama's desire to compromise with Russia.
Defense Secretary Gates, off to Singapore for a regional security summit, says US sees no 'crisis' in Pyongyang's 'very provocative' display of force this week.
Defense secretary applies lessons of Iraq, Afghanistan to new Pentagon budget.
US officials say the system is merely a protection against rogue states like Iran.