X-37: a spaceplane developed in secret for classified missions in Earth orbit. It sounds like something from a Cold War techno-thriller novel but the United States Air force’s X-37B is a real project and it is flying today. Tracy McConnell reveals the truth.

Image of X-37

Shadowy spacecraft: OTV 1 on its return to Earth after its secret mission. (Image credit: USAF)

(For more up to date information on the X-37, see X-37: Speculation, Secrets and Espionage.)


Ever since President George W. Bush announced the upcoming retirement of the Space Shuttle fleet in 2004, there has been a flurry of commercial companies pressed forward with designs to possibly take its place. Virgin Galactic’s Space Ship One, to SpaceX’s, Falcon 1 and Falcon 9 rockets. However multi-billion dollar conglomerates weren’t the only people investigating the possibility of space travel. The USAF has been involved in designing and building its own viable space aircraft: the mysterious Boeing X-37.

Image of -NASA X-37_spacecraft

An artist's conception of the original (unbuilt) NASA X-37A Advanced Technology Demonstrator as it glides to a landing on Earth. Its design features a rounded fuselage topped by an experiment bay; short, double delta wings (like those of the Shuttle orbiter); and two stabilizers (that form a V-shape) at the rear of the vehicle. (Image credit: NASA/Marshall Space Flight Center)

It has quite a long convoluted history beginning with NASA, Boeing and the USAF contributing nearly $500 million between 1999 and 2004 towards designing and construction this unmanned space craft. Its main design is similar to that of the space shuttle in that it is a vertical take-off vessel (like a rocket) which lands horizontally (like an aeroplane).

Image of WhiteKnight

White knight II: this high altitude aircraft has been designed to allow it to carry a smaller spacecraft/aircraft between the two engines and then allow the smaller test craft to be released in high altitude. It’s the successor of the White Knight and both have been used in the past to test drop the X-37, X-37B and Virgin Galactic SpaceShipTwo. (Image credit: Virgin Galactic)

Since September 2004 the X-37 project  has been overseen DARPA (the Defence Advanced Research Projects Agency), where it became a classified project.  After extensive testing and some tweeks to the original structure, the Boeing X-37 was scheduled for launch. Unfortunately due to atmospheric conditions and technical problems, the initial flight, which was actually a drop from a high altitude aircraft known as the White Knight, had to be postponed several times before finally occurring on 7 April 2006. It is important to realise that up until this point, this mammoth multi-billion dollar project had yet to make it into space. Several other free flight tests followed successfully and it was decided that it was now time to develop the X-37B Orbital Test Vehicle (OTV).

Atlas V: the rocket that safely carried the mysterious X-37B OTV 1 and OTV 2 into space. At launch the craft are concealed in the rocket's payload shroud. (Image credit: NASA)

The OTV-1 is a re-usable robotic space plane also referred to as the Advanced Technology Demonstrator. After its completion and several further delays with the launch due to issues with the prospective launch vehicles, the X-37B finally blasted into space on 22 April 2010 safely ensconced within the Atlas V rocket. Once deployed into space the spacecraft began its orbit of the Earth which lasted until 3 December 2010. During this time the X-37B OTV2 was designed for launch on 5 March 2011.

Image of X-37 inspection

The X-37B Orbital Test Vehicle after it landed on the runway at Vandenberg Air Force Base in California on 3 December 2010. Notice the size of the spacecraft in comparison to the personnel in the protective suits who are responsible for conduction the initial tests and declaring the area safe. The X-37B is a very small vehicle compared even to the lightest of single fighter 'planes. (Image credit: US Air Force)

So the question is… what was it doing? This unmanned spacecraft, which is part of a classified project and which was in orbit for 225 days? It was supposedly testing new spaceflight technologies, before they are committed to be used on other however many alternate theories have been floating around almost since the Air Force took control of the project due to lack of other funding.

The x-37B Orbital Test Vehicle is an unmanned space test vehicle for the USAF.

Source Space.com: All about our solar system, outer space and exploration

One newspaper, the (government-run) China Daily, fears that this spacecraft may spark another space race, surrounding the use of weapons launched from space based platforms, this would of course be in direct violation of a January 2001 United Nations Resolution which states “The exploration and use of outer space … shall be for peaceful purposes and shall be carried out for the benefit and in the interest of all countries, irrespective of their degree of economic or scientific development. …prevention of an arms race in outer space would avert a grave danger for international peace and security”. Other news organisations speculated about its possible use as a spy satellite, and this theory seems to be based on amateur sky watchers locating it over North Korea and Afghanistan. X-37B’s orbital period, 4 days, and height, 410 km (255 miles), are congruent with those of a military surveillance satellite. The theories continued to run rampant when the mini shuttle seemed to disappear for two weeks in August last year. When the amateur astronomers and sky watchers re-discovered it, the X-37B seemed to be on a different trajectory and orbit, being 30 km higher than before and now on a six day orbital period. The rational readers will suggest that it was simply conducting some kind of manoeuvrability test that probably changed its direction and speed. And that’s a perfectly plausible explanation, but where’s the fun in that?

Image of X-37 on Shuttle

The X-37 was originally a NASA project to be carried into space on a Shuttle mission and released for an independent return to Earth. (Image credit: NASA)

The problem with this spacecraft mission and its successor OTV2 which launched on 5 March 2011, is that they are both classified, and no real information is available regarding their mission outside the Pentagon. The fastest way to create a conspiracy is to classify something, and a spacecraft as amazing as a mini robotic space plane is just too interesting not to result in people asking questions. Maybe by the time OTV2 lands, we will have some answers. Just remember that its solar arrays allow it to remain in orbit for up to 270 days. So keep the speculation going in the mean time and keep an eye for it landing sometime in early December.

(For 2012  information on the X-37, see X-37: Speculation, Secrets and Espionage.)

Article by Tracy McConnell.


Linixs · October 18, 2014 at 19:19

270 Days bearley any room in something the size of a small van, Look at the size of it.. u couldn’t spend 8 months in something so small.. just the amount of food needed for 2 years would fill it.. never mind water air tanks and electronic equipment.. they must of got off it somewhere

    admin · October 20, 2014 at 10:25

    Hi, thanks for your comment but no one is saying there were people on the X-37. From a USAF factsheet:

    The X-37B Orbital Test Vehicle, or OTV, is an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform for the U.S. Air Force.

nathan · November 13, 2013 at 21:13

i never thought that it was going to be back so fast.

Dezcartez · March 9, 2012 at 11:37

Exactly what worries NASA enough to have people in semi-space suits inspect the mini shuttle after landing in order to declare it “safe”?

    admin · March 10, 2012 at 08:50

    It’s in case of hydrazine leakage from the craft’s propulsion system. They used to wear the the same gear around Shuttle Orbiters immediately after they landed too, but no one ever paid any attention.

admin · May 3, 2011 at 08:52

Sadly, flying the X-37 to Mars is not in the tiniest bit feasible. It is also a tad on the small side (see the diagram), I’d guess it’s payload volume would match a smallish van. Finally the first flight was observed in Earth orbit and tracked by amateur observers throughout its mission (see http://en.wikipedia.org/wiki/USA-212 )and I would assume the same goes for the current one. Nice speculation though.

Agent Smith · May 2, 2011 at 22:59

Ever imagined that this spacecraft was designed to transport equipment from Earth to Mars and back? Sounds crazy? Think about it… 🙂

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