Covert Mission: U.S. Airforce's Boeing X-37B Nears 1 Year in Orbit

X-37B space plane has been orbiting Earth uncrewed for almost one year on a latest secret mission. The U.S. military's robotic space plane was launched onto a United Launch Alliance Atlas V rocket on May 20, 2015, kicking off X-37B program's fourth flight. This mission, dubbed OTV-4 (short for Orbital Test Vehicle-4), remains a covert affair.

The unmanned space plane has spent the last year roaming around the Earth and people still don't know what they're up to. On May 20, it will be exactly one year since the Boeing left Earth. However, on the eve of its anniversary, talks about the true reason of its mission have lit the internet up like wildfire, mirror.co.uk reported.

There have been several write ups published in the Russian press implying that it is really part of a space warfare mission created to allow the United States to destroy satellites. Despite the speculations, America has remained tight-lipped about what the mysterious space plane is doing.

"I can confirm the fourth OTV mission is approaching one year on orbit," Air Force spokeswoman Capt. Annmarie Annicelli said in response to Space.com's inquiry about the X-37B's activities. The X-37B looks like a smaller version of NASA's now-retired space shuttle orbiter. The military space plane is 29 feet long and 9.6 feet tall. It has a wingspan of nearly 15 feet. The spacecraft has a payload bay of about the size of a pickup-truck bed. It has a launch weight of 11,000 lbs. and is powered on orbit by gallium arsenide solar cells with lithium-ion batteries.

According to CBS News, the spacecraft also blasted into orbit from Cape Canaveral in Florida, carrying a brand new type of ion engine called a "Hall thruster", and an experiment designed by NASA to test how 100 types of materials respond to the harsh conditions of space.

At the time Laura Grego, senior scientist at the Global Security Program at the Union of Concerned Scientists, told Space.com there was "no compelling reason" why experiments should be carried aboard a top-secret craft. "Describing some of the activities on this X-37B flight may be meant to lessen its mysterious nature," she said.

"While the space plane isn't particularly well suited to a space weapons role, most of the space plane's details are still classified, and the Pentagon appears committed to continuing the program. "So it still seems to be a source of anxiety for some of those concerned about the increasing weaponization of space."