The mysterious spacecraft X-37B has returned to Earth

Last night October 17 (US time), the mysterious American spacecraft X-37B returned to Earth and landed safely in California after nearly two years of "wandering" in orbit.

>>>The mysterious ship x-37b is about to return to earth

X-37B is built by Boeing Group, 9m long, 4.5m wingspan, weighs 4,989kg and uses solar energy. It was a miniature shuttle-like unmanned aircraft and used for a secret US mission that lasted 674 days.

Infrared photo of US X-37B - (Photo: AP)

The next X-37B flight is scheduled to take place next year - (Photo: AP)

It landed at Vandenberg Air Base in California on October 17 morning local time.

US Air Force officials say the X-37B was born to test advanced technologies for the future generation of " reusable " shuttles in the future.

However, some doubts say it is used to monitor a Chinese space lab that has not been recently appreciated by experts.

According to the BBC, this is the third time the US Air Force has put the X-37B into orbit. The previous two flights of X-37B were in April 2010 (returning after 8 months) and in March 2011 (returning after 15 months).

The fourth X-37B flight is expected to take place next year from Cape Canaveral, Florida.