What is the U.S. military’s secretive ‘space plane’ up to?

A computer-generated image of the X-37B space plane (Image credit: NASA/Boeing)The X-37B Orbital Test Vehicle 3, the U.S. Air Force's secretive robotic space plane, has been on its latest mission for over 10 weeks now, zipping around in low-Earth orbit since it made its third launch into space back on December 11th. However, given what the pint-sized robot space shuttle is capable of, or should I say incapable of, it begs the question 'What is the military using it for?'

The design of the X-37B Orbital Space Vehicle 3 (OTV-3) design is very similar to the Space Shuttle, however it is about one-quarter the size and it is completely unmanned. Like the Space Shuttle, it launches into space on a rocket booster (in this case, an Atlas V rocket), and it is capable of returning to Earth and landing on a runway like any conventional aircraft. This 'reusability' is apparently the cornerstone of the design, and the reason the U.S. Air Force is pursuing the program.

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However, in a report from last November, penned by the Union of Concerned Scientists (UCS), they state: "While this 'space plane' could perform a range of missions, in each case we can identify a better, more efficient, and/or cheaper way of doing each of those tasks."

The main reason for its limitations is the very reusability of its design. The addition of wings and landing gear, and the reinforced structure needed for it to land like a normal aircraft, add tons of extra mass to the spacecraft. This makes it necessary to use a large rocket to launch it into orbit — a rocket that would otherwise be able to hold several other, smaller, spacecraft that could do the intended jobs of the X-37B better. Additionally, a larger mass means more fuel needed to launch it into space and also more on-board fuel for maneuvers and landings, thus increasing the costs compared to other spacecraft.

As a spy platform, it is woefully inadequate compared to other orbital craft, as its size and mass make it less maneuverable and more easily detected. In fact, amateur satellite trackers have already spotted it and figured out its orbit.

"OTV-3 remains in its initial orbit, maintaining altitude with periodic engine firings," said Ted Molczan of Toronto, who is an active member of a worldwide amateur satellite tracking network, according to Space.com. "Unlike the first two missions, its ground track does not closely repeat at the frequent intervals that would suggest an imaging reconnaissance mission."

Smaller, dedicated satellites can also do the other jobs that have been suggested for the X-37B, such as inspecting, refueling and repairing satellites in orbit. Current methods of testing equipment in orbit by use of a recoverable craft with a parachute have been done for decades at much lower costs. Also its cargo space is so small that it can only deploy or capture the smallest of satellites, making it inadequate for those jobs as well.

The X-37B also does not make a very good space weapon. Small satellites would be far more effective as satellite killers, as they could maneuver closer to their targets and be harder to spot as they went about their missions, and suggestions that the space plane could be used as 'space bomber', dropping a payload onto an enemy target from space, ignore how inefficient and costly that would be compared to using conventional bombers to do the same job.

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One aspect of using spacecraft that would be very useful for military purposes is for troop transport via sub-orbital flights. However, unless the X-37B is a small-scale prototype for a larger vehicle, its size makes that mission impossible, and it would also be limited by the fact that it cannot be quickly deployed, thus eliminating any benefit that could be achieved by the short sub-orbital flight time.

So, with everything that this spacecraft can't do, or is completely inadequate for, or that other spacecraft can do better and for a lower cost to the taxpayer, exactly what use is the U.S. military planning on putting it to that they couldn't get out of other, more easily manufactured and launched spacecraft? There is a certain reputation (deserved or not) for military overspending, but this seems like going a bit overboard, and falls more into the realm of "look at us, we have a cool space plane" rather than it being for some practical purpose.

The UCS's recommendation for the project is that the administration and Congress should re-examine it, and be clear about its goals and about the money being spent on it, but who knows, maybe there's a reason for it being up there that the UCS hasn't considered yet. Diminutive space aliens?

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