You can't slip much past dedicated amateur astronomers. A month after the United States Air Force launched its space plane, the X-37B, under a veil of secrecy, backyard sky-watchers say they've found it, along with clues to its mission. Though the military still won't open up about what the classified X-37B actually is, officers have been insistent about what it isn't: a space weapon. Indeed, defense experts have guessed recently that the craft is testing next-generation spy satellite tech, and the observations back that up.

The amateur sky watchers have succeeded in tracking the stealthy object for the first time and uncovering clues that could back up the surveillance theory. Ted Molczan, a team member in Toronto, said the military spacecraft was passing over the same region on the ground once every four days, a pattern he called “a common feature of U.S. imaging reconnaissance satellites.” In six sightings, the team has found that the craft orbits as far north as 40 degrees latitude, just below New York City. In theory, on a clear night, an observer in the suburbs might see the X-37B as a bright star moving across the southern sky [The New York Times].

In addition, the plane's path would carry it over places the U.S. is interested in watching, like Iran, Pakistan, and North Korea, according to Greg Roberts, one of the astronomers to track the X-37B. More than uncovering its secret mission, he was interested in finding the plane because it was difficult. Said Roberts:

"If the data were freely available, we would probably not have bothered with it. I see little sense in tracking objects for which data is freely available. It's like reinventing the wheel. So as long as there are missions with little or no information, I personally will be interested in the challenge of finding them" [MSNBC].

For more about the Air Force in space, check out DISCOVER blogger Phil Plait's post

at Bad Astronomy. Related Content: Bad Astronomy: What Is the Air Force Doing with Space?

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Image: U.S. Air Force