The U.S. AirForce's mysterious X-37B robot space plane returned to Earth today (Dec. 3) witha successful landing at Vandenberg Air Force Base in California before sunrise.

Air Forceofficials hailed the unmanned X-37Bspace plane's successful landing, though its mission remains shrouded insecrecy because of its classified nature. But Vandenberg's 30th Space Wing didnot shy from snapping photos of the X-37B vehicle, known as the Orbital TestVehicle 1. Take a look at those first photos below:

Nose to Nose: X-37B space plane builder Boeing released this photo of the unmanned spacecraft just after its landing on Dec. 3, 2010.

The spacecraft spent 220 days in space before gliding to a predawn landing at the Vandenberg Air Force Base in California.

See a video of the X-37B landing here.

HomeAgain: Despite itsrobotic nature, the X-37B space plane received a warm welcome from Air Forcecrews at Vandenberg.

Here, the vehicle appears to be undergoing safingprocedures after landing on Dec. 3 at 1:16 a.m. PST (0916 GMT).

Significantweathering, or discoloration, can be seen on the spacecraft's upper thermalblanket insulation.

X-37B inProfile: An AirForce photographer snapped this profile view of the X-37B shortly after itsDec. 3 landing.

The X-37B isabout 29 feet (9 meters) long and has a wingspan of just over 14 feet (4meters) across. It stands just over 9 1/2 feet (3 meters) tall and weighsnearly 11,000 pounds (about 5,000 kg). For comparison: Two X-37B vehicles,arranged in a line nose to aft, could fit in the payload bay of a NASA spaceshuttle. Boeing's Phantom Works division in Seal Beach, Calif., built thespacecraft.

This SPACE.comgraphic of the X-37B depicts the characteristics and capabilities of theunmanned space plane.

Up Closeand Personal: A crewof vehicle handlers clad in suits to protect against hazardous materials (likeany remaining rocket fuel) approach the X-37B robot space plane after itssuccessful Dec. 3 landing at Vandenberg Air Force Base in California.

X-37BWalkaround: Thisphoto released by the Air Force shows the nose of the mysterious X-37B spaceplane as recovery crews take measurements and other readings after its Dec. 3landing at Vandenberg. The X-37B's unique V-shaped "ruddervators" ?which serve as its tail stabilizers ? are visible as well as a deployed airbrake. [Gallery- The Air Force's X-37B Space Plane]

PayloadBay Doors: Here, theX-37B space plane is seen in profile as post-landing work continues. The logosof Boeing and the Air Force are visible on the reusable spacecraft's hull. Theyappear between lines that outline the X-37B's payload bay, which is about thesize of a pickup truck bed and can hold experiments, small satellites and asolar array panel that it used to generate power.

WelcomeHome: This X-37Bspace plane's payload bay is seen clearly in this side view, as is the scale ofthe spacecraft compared to a human. [Videoof the X-37B in space]

The X-37Bbegan its life in 1999 as a NASA project, then transferred to the Pentagon'sDARPA office in 2004. The Air Force took over in 2006. This mission launched onApril 22, 2010. The flight's purpose and cost are classified.

Looking Up: This side view of the X-37B was taken by a Boeing photographer, revealing the grooved runway of Vandenberg Air Force Base where the robotic space plane landed today. An army of Vandenberg workers replaced hundreds of small steel plates on the runwary to smooth it out in order to avoid damage to the X-37B's tires during landing, according to the Santa Maria Times newspaper.

Job WellDone: With the firstX-37B spacecraft back on Earth, the Air Force is now looking ahead to the nextlaunch. The Air Force has ordered the construction of a second X-37B ? theOrbital Test Vehicle 2 ? for a mission to launch in the spring of 2011.

Gallery - The Air Force's X-37B Space Plane, Video of X-37B in Orbit

Most Dangerous Space Weapon Concepts Ever

Experts Question Usefulness of Air Force's Robotic X-37B Space Plane

You canfollow SPACE.com Managing Editor Tariq Malik on Twitter @tariqjmalik.