In his blog post entitled Bloopers in Space, Jim Oberg responds to a recent article in Spaceflight, the magazine of the British Interplanetary Society, which claims the X-37B's mission is to spy on China's newly launched Tiangong-1 space station. Nice try, but no cigar. The answer lies in the differences in the RAAN (Right Ascension of the Ascending Node) of the two craft. Despite having similar inclinations and altitudes, their planes are nearly perpendicular and two craft will pass each other at some 8000 meters per second. So, the X-37B is hardly tracking the Tiangong-1. He also points out that it would have been a pretty neat trick to have anticipated the Tiangong-1's orbit back when the X-37B was launched.