If your secret space plane's in orbit and doing its secret thing well enough, why bother bringing it home? This appears to be the mindset of the Air Force regarding its experimental X-37B space plane, the billion-dollar robotic vehicle's orbital flight being extended beyond the 270 days it was initially designed for. While the Air Force has stated that the vehicle is meant only for conducting orbital science experiments, analysts say the X-37B is capable of much more, and could perform additional tasks such as acting as an orbital spy, sneaking up on and tampering with enemy satellites or hauling small batches of supplies to the International Space Station. Perhaps the most interesting thing is that the X-37B could stay in orbit for that much longer. Although the Air Force said last year that the X-37B could last nine months above the heavens before its power and fuel ran out, an inside source commented that "it sips power and fuel like a Prius." Click through the break for the full X-37B schematics, which -- crazily enough -- look nothing like a Prius.