Experimental X-37B Robot Space Plane to Launch Thursday
The X-37B space plane prototype is seen on a runway during flight tests in this undated photo released by the U.S. Air Force.
Credit: USAF

The United States Air Force plans to launch its first robotic X-37B space plane Thursday on a mission that is a forerunner of things to come. A second mini-space plane is already under contract and is projected to be launched next year.

New details regarding the mini-space plane and its upcoming Thursday liftoff atop an Atlas 5 booster were discussed today during a U.S. Air Force-held media press briefing.

The X-37B vehicle's history stretches back to the late 90s, with NASA kick-starting the project. It was later picked up by the Defense Advanced Research Projects Agency (DARPA) and ultimately found a home within the Air Force. The project is now under the wing of the Air Force Rapid Capabilities Office. [X-37B spacecraft photos.]

?After a tumultuous history of sponsorship, it?s great to see the X-37 finally get to the launch pad and get into space,? said Gary Payton, U.S. Air Force Deputy Under Secretary for Space Programs in a media press briefing today.

Auto-pilot mode

The small X-37B spacecraft resembles a miniature space shuttle and is equipped with its own payload bay about the size of a pickup truck bed ? ample space to hold a couple of small satellites that are a few hundred kilograms each, Payton noted.

According to released specifications, the X-37B space plane weighs about 11,000 pounds and is just over 29 feet in length. It stands slightly more than 9 1/2 feet in height and has a wingspan just over 14 feet across.

The initial X-37B flight is designed to loiter in space up to 270 days. After retracting its solar array and closing payload doors, the space plane would re-enter in automated mode.

?It?s on auto-pilot, literally, the entire time the rest of the way in,? Payton told SPACE.com, adding that the Air Force is ready in case the spacecraft malfunctions. ?We?ll be tracking it over the Pacific...and it does have a destruct mechanism on it."

The X-37B is designed to make an autonomous landing at Vandenberg Air Force Base in California, or at neighboring Edwards Air Force Base as backup.

?Similar to the shuttle, it?ll take half-the-world to come home,? banking on redundant digital flight control systems on the vehicle, Payton said. "I?ve got a lot of confidence in the ability of this bird to come back home autonomously."

On order: second space plane

Payton said the X-37B space plane provides a new way for the Air Force to conduct on-orbit experiments. More important is experience gained in quick turnaround of the returned vehicle, the honing of low-cost operations and maintenance expertise, as well as sharpening payload change-out skills, he added

Fast turnaround of X-37B, Payton told SPACE.com, could be measured in several days to 10 to 15 days or less. ?I?d like to see this X-37 handled much more like an airplane,? he said, likening that ability to the SR-71, an advanced, long-range, Mach 3 and faster strategic reconnaissance aircraft.

The new unmanned space plane will test a new batch of reusable technologies, including new silica re-entry tiles, as well as ?other technologies that are sort of one generation beyond the shuttle,? Payton said.

Already on order is a second mini-space plane.

?We do have a second tail number on contract. Currently, we?re looking at a 2011 launch for that second tail number. That assumes everything goes properly as predicted on this first flight,? Payton said.

Additional copies of the mini-space plane ?depends on success of these first two birds,? he told SPACE.com, and if operations and maintenance costs are low and fast turnaround times are achieved.

Classified budget

The X-37B initiative leverages extensive and early NASA, DARPA, Air Force, as well as investments by its builder ? Boeing Phantom Works. The funding level for the overall project is within the Air Force?s classified budget, explained Angie Blair, an Air Force spokeswoman for the project in an earlier interview.

According to information released by the U.S. Air Force, the X-37B Orbital Test Vehicle (OTV) will provide a flexible space test platform to conduct various experiments and allow satellite sensors, subsystems, components and associated technology to be efficiently transported to and from the space environment where it will need to function.

The X-37B will also prove new technology and components before they are committed to operational satellites.

The OTV is the first vehicle since NASA?s shuttle orbiter that has the ability to return experiments to Earth for further inspection and analysis.

Experimental test platform

?The X-37B is the only self-contained effort intended to be an economically viable experimental test platform on-orbit for months at a time and then return,? said David Hamilton Jr., the Air Force Rapid Capabilities office director in a recently released article by the Air Force.

Hamilton explained the X-37B is a risk reduction vehicle for space experimentation that explores concepts of operation for a long-duration, reusable space vehicle.

Hamilton explained that the OTV has the potential ?to revolutionize how the Air Force operates in space by making space operations more aircraft like and adding in the capability for returnable plug-and-play experiments.?

Leonard David has been reporting on the space industry for more than five decades. He is past editor-in-chief of the National Space Society's Ad Astra and Space World magazines and has written for SPACE.com since 1999.