Top Secret Air Force Spaceplane Lands with Sonic Boom After Two Years in Orbit 

The US Air Force’s secretive X-37B spaceplane landed yesterday after 718 days in orbit—just twelve days shy of a full two years. What was it doing up there in the sky? The government won’t say. Even the spaceplane’s budget is a secret. But the X-37B’s landing wasn’t so stealth. The spaceplane caused a sonic boom that…