Its real purpose is a mystery, and it just passed 600 days in orbit.
The Air Force, NASA, and Boeing are working together on a top secret ‘space plane’ known as the X-37B space plane, or the Orbital Test Vehicle (OTV). It was launched on May 20, 2015, from Cape Canaveral, the journey marks the fourth longest orbit in the X-37B test period with a previous mission lasting as long as 675 days.
At 8.8 meters long (or 29 feet) the X-37B is a relatively small craft, roughly 1/4 of the size of our Space Shuttle. The plane contains a payload bay and robotic arm. It launches traditionally (vertically) and lands on a runway (horizontally). Impressively it can travel up to 28,000 kilometers per hour (17,500 mph) on solar powered batteries.
The public is aware of payload deliveries including material science experiments and the delivery of an ion thruster, but the plane’s mission objective is a bit unclear:
“primary objectives of the X-37B are twofold: reusable spacecraft technologies for America’s future in space and operating experiments which can be returned to, and examined, on Earth.”
Some believe the plane’s true mission objective is surveillance; with a specific look at obtaining higher resolution images from the ground, than high orbit satellites can achieve. Or counter satellite operations.
While the true nature of the X-37B is still a mystery, this hybrid space shuttle-airplane is one amazing piece of technology.