The Boeing X-37, also called the Orbital Test Vehicle (OTV), is an unmanned American spacecraft.  Its first orbital mission was on 22 April 2010 returning back to Earth on 3 December 2010.  A second X-37 was launched on 5 March 2011 and has not yet returned to Earth at time of writing (23 April 2012) spending over a year in space.  The United States Air Force (USAF) described the mission as classified and limited details have been released on why the craft was launched, what the payload is onboard and future uses of the craft.  This has led to a lot of speculation on its “true mission”.

image of X_37_cutaway

Inside the X-37:JP-8 is jet fuel, H2O2 is hydrazine.RCS stands for Reaction Control System.(image credit:Boeing)


If you would like to read more into the beginnings of X-37 then please click here. But I will look at the conspiracy theories and future uses for the X-37.

The USAF revealed that the mission of the X-37 was to test new space technologies, but with few details released on the mission the conspiracy theorists have began to speculate.  The main theory is that it has been sent up to spy on the Chinese.  The China Space Program has really picked up momentum.  They launched a spacelab called Tiangong-1 in September 2011 and expect to send a crew there this year.  Of course the Americans are wary at the pace of developments especially as China plans to send another probe to the Moon within the next three years and send a manned lunar mission by 2020.  This will significantly close the gap between the two superpowers.  So, although the Chinese spacelab is unmanned at the moment, the theory is that the X-37 is spying on it.

It is true that it looks like the X-37 does share a similar path around the globe as the spacelab Tiangong-1 and it has been tracked from the ground by those intrigued by its purpose as being on the same route.  But although similar in that they are both about 300km (180 miles) above Earth with roughly a 43 degree inclination, their orbit is vastly different by some 100 degrees, meaning that they intersect just twice per orbit.  So, would it be correct to say that when the two vehicles pass each other the USA must be gaining very detailed results from their espionage?  Wrong, when they pass each other it is at speeds up to 8000 meters per second so gaining any valuable data would be near impossible!

Another important point to note is the dates when Tiangong-1 was launched and when X-37 was sent into orbit.  If X-37 was a spying mission then surely the launch of Tiangong-1 preceded it?  No, X-37 was sent up in March 2011 with the Chinese Spacelab launched in September 2011.  So if the Americans were sending their craft up to spy on a lab that was not yet in space, then it would have been a guessing game to decipher when Tiangong-1 would be launched and the orbit it would take! So is it a spying spacecraft?

In my opinion most likely it is not, if the USA wanted to listen in on Tiangong-1 they could do it probably without the effort of sending a craft into space, but everyone loves a conspiracy theory!


Another line of thought is that it has been sent up to tamper with enemy satellites as the X-37 has the capability to manoeuvre and change its orbit.

To me this sounds like something out of a James Bond movie and reminds me of one of the earlier Bond films starring Sean Connery, You only live Twice.  In this film an American space craft is swallowed up by a mysterious enemy capsule in what can only be described as a “Spacejacking”.  This almost starts all out nuclear war, well that is before 007 saves the day!  Fact or fiction, some people still believe that the X-37 could serve as an orbital bombing machine and that the secret payload onboard is munitions!A scary thought which I hope is not true.

image of James bond spaceships

Spacejacking Bond style.The Gemini mockup seen here was once an attraction here at Armagh Planetarium.(Image credit:United Artists)


What interests me more is the capability of one day having a manned X-37 flight.

The X-37 is thirty feet in length and approximately nine feet high, so too small to have astronauts onboard.  But, Boeing has plans to build an X-37C spacecraft which would be a 165% scale up on the one being utilised now.  This could allow both cargo and passengers to orbit in space and even travel to the International Space Station.  This could allow America to once again have their own space transport vehicle and not be reliant on the Russian Soyuz rocket as they are at the moment.

image of x37c family

The X-37B drawn to scale with the proposed X-37C and a Shuttle Orbiter.To the right are Atlas V rockets with X-37s in launch configuration.The heavier X-37C requires the addition of strap on boosters to the Atlas.(Image credit:Boeing via


Perhaps the secrecy surrounding X-37 stems from the fact that commercial companies are developing spacecrafts that they hope can replace the shuttle.  One such craft being developed by the company SpaceX is called the Dragon.  So perhaps secrecy is the best policy to hid potential data that competitors could steal.

image of X-37 checks

USAT techicians check out an X-37 after its return.The protective clothing is in case of leaks of toxic hydrazine from the vehicle's propulsion system.(Image credit:USAF)


Another use for the X-37 would be as a transport vehicle for satellites that are facilitating experiments in orbit.  The X-37 could bring the satellite up into orbit and once the experiment has been completed, recollect it and bring it back down for the results to be analysed and of course the satellite can be reused again.

So in conclusion, the X-37 is a bit of a mystery.  It was designed to spend around nine months in orbit, but the second mission has endured over a year in space with no plans released for its return yet.  We still don’t know what exactly the craft is doing up there and what the payload is.  But, it has proven to be durable and reliable (the top brass seem pleased with it) which is great news for the Americans given the cutbacks in the space program by President Obama.  Watch this space for further details on X-37, who knows one day it could be taking astronauts into space and could become the permanent replacement for the Space Shuttle.  Or perhaps you think that it is indeed a vehicle used in some sort of espionage plot.

Either way I would love to hear your comments on it!

(Article by Sinead McNicholl)




George Bonnett · August 1, 2014 at 00:35

I know that they launch the X-37 from Vandenberg AFB, California so if I knew the orbit I could possibly see it with the right telescope.

George Bonnett · August 1, 2014 at 00:32

HAARP has been shut down for quit a while here in Alaska as far as I know. Good website.

Andromeda Cross · April 30, 2014 at 22:56

The following is NOT FACT, it is a fictional theory, for entertainment purposes ONLY.

What is DARPA’s secret with this mission?

There are 2 possible scenarios.

Either, The (Defense Advanced Research Projects Agency) is either studying a defensive device or posture on Earth, or studying a defensive posture or device in space.

The presumed threat or study could pertain to something terrestrial or extraterrestrial.

If it is something on Earth, then DARPA could be studying the effects of something currently being ‘tested’ on Earth or monitoring an extraterrestrial presence within our atmosphere. Either or, they are studying and or searching a ‘known’ cause for its effect on the Earth’s weather patterns, structural patterns of plate tectonics, atmospheric conditions, oceanic conditions, etc.

If it is something in space of terrestrial or extraterrestrial origin, then, DARPA could be utilizing a newly developed device to study movement of bodies in space or frequencies and origins of something from space which could be considered a threat.

However; since it is just using ‘ONE’ ship, within .. low Earth orbit .. ONLY, (HAARP – High Frequency Active Auroral Research Program ) comes to mind because this is a DARPA project pertaining to low atmospheric conditioning.

Making the threat of an impending extraterrestrial presence NON EXISTENT; otherwise, I would ‘suppose’ the monitoring for unknown extraterrestrial activity currently in our atmosphere would bring about a more demanding and obvious response.

To me this means that any and all anomalies that we are currently witnessing on Earth is in direct response to DARPA/HAARP testing.

Slab Hardrock · January 24, 2014 at 17:33

While tooling around for more info on the X-37 program I came across your blogpost, and I thought you might be interested in my thoughts on the advantages of it as a spy platform:

RC · January 28, 2013 at 09:34

Intriguing article, well written as an overview of the X-37. H2O2 however is Hydrogen Peroxide, Hydrazine is N2H4, both of which have been used in rocket fuels. Do you have any clarification on the fuel used?

dj lopez manchester · July 23, 2012 at 18:31

The x15 i mean x 37 should be used as a space shuttle end of discussion.

US Rockets, past, present and future | Astronotes · December 5, 2014 at 12:57

[…] V (used to launch interplanetary probes such as MAVEN and Curiosity and well as the USAF’s X-37), Delta IV M and IVH (used to launch the Orion spacecraft on its first […]

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