We may finally have a clue what the U.S. Air Force's secret space plane, the X-37B, is up to on its record breaking mission in the heavens. Amatuer satellite trackers have noticed that the robo-shuttle's orbital path is nearly identical to China's brand new space station, Tiangong-1, which was launched in September.
Remember, the X-37B can stay aloft for nearly a year and is capable of changing its orbits around the Earth. These features, combined with the secrecy surrounding its missions have prompted many people to speculate that it is a spy craft capable of launching small spy satellites and snooping on other nation’s satellites up close.
"Space-to-space surveillance is a whole new ball game made possible by a finessed group of sensors and sensor suites, which we think the X-37B may be using to maintain a close watch on China's nascent space station," Spaceflight editor Dr. David Baker tells the BBC.
Remember, OTV-2, the second of two X-37Bs, launched last March and recently surpassed its official endurance of 270 days in space. It's very plausible that Air Force officials decided to keep the bird aloft past its max endurance in order to get a better look at the Chinese space station. Tiangong-1 will receive its first human occupants later this year and is intended to serve as a prototype for several larger Chinese space stations.
From the BBC:
The current mission was launched on an Atlas rocket and put into a low orbit, a little over 300km up, with an inclination of 42.79 degrees with respect to the equator - an unusual profile for a US military mission which would normally go into an orbit that circles the poles.Read more about the U.S. and China in space here.
The X-37B's flight has since been followed from the ground by a dedicated group of optical tracking specialists in the US and Europe, intrigued by what the vehicle may be doing.
These individuals have watched how closely its orbit matches that of Tiangong.
The spacelab, which China expects to man with astronauts in 2012, was launched in September with an inclination of 42.78 degrees, and to a very similar altitude as the OTV. "The parallels with X-37B are clear," Dr Baker says in Spaceflight, the long established magazine of the British Interplanetary Society.
"With a period differential of about 19 seconds, the two vehicles will migrate toward or against each other, converging or diverging, roughly every 170 orbits."