US X-37B Orbital Test Vehicle
© AP Photo/ US Air Force
After over 2 years in space, advanced US re-entry X-37B Orbital Test Vehicle spacecraft successfully landed at NASA's Kennedy Space Center.

This was the fourth flight of this vehicle. Boeing started the secret X-37B Orbital Test Vehicle project under NASA's aegis in 1999. Originally, the reusable X-37 was intended to repair satellites in orbit. However, in 2004 the program was classified and handed over to the US Air Force.

According to the US Air Force, the X-37B Orbital Test Vehicle is "the newest and most advanced re-entry spacecraft."

Since 2010, the spacecraft are carrying out test orbital flights. According to experts, X-37 can be used both for testing new technologies and for the delivery of reconnaissance satellites into space. Potentially, they can be equipped with weapons, but the Pentagon assures that this is not part of its plans.

The X-37B program is the newest and most advanced re-entry spacecraft that performs risk reduction, experimentation and concept of operations development for reusable space vehicle technologies.

On March 20, 2015, a United Launch Alliance (ULA) Atlas V rocket successfully launched the AFSPC-5 satellite for the US Air Force from Space Launch Complex-41.