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US Air Force Launches Secret Flying Twinkie
Spectrummag writes "One of the most secretive US Air Force spaceflights in decades, launched this month, is keeping aficionados guessing as to the nature of the secret. The 6000-kilogram, 8-meter X-37B, nicknamed the flying Twinkie because of its stubby-winged shape, is supposed to orbit Earth for several weeks, maneuver in orbit, then glide home. What's it for? Space expert James Oberg tracks the possibilities."
First off, while the article is a good one, it was actually written before launch. After the launch, there have been some intriguing details, particularly the fact that NOBODY outside of the classified world has been able to actually locate it in the sky. Normally amateur skywatchers are pretty good at locating satellites after they've launched, but apparently not in this case. Here's two possible explanations for this:
* the X-37B is testing low-visibility features, possibly either a stealthy payload shroud, low-visibility solar panels, or some other sort of camouflage/stealth system
* One possibility posited by Jim Oberg (the article author) elsewhere is that this may be the first test ever of an atmospheric orbital plane change, a technique desired since the 90s or earlier, where a spaceplane uses its wings to dip into the atmosphere while travelling at hypersonic speeds to alter its trajectory. The X-37B apparently doesn't have a high enough L/D ratio to perform an extreme plane change (e.g. near-equatorial to polar), but it may be able to alter its trajectory enough to make it damn hard to track from the ground.
Now, some people have been asking why a reusable spaceplane would be useful to the US Air Force. Some possibilities:
* The atmospheric plane change capability mentioned above, which would allow the Air Force to deploy satellites into trajectories unknown by those observed. One major problem with satellites is that other countries typically know when they'll be overhead, so they just make sure that anything they're trying to hide doesn't occur during those hours.
* If you add a retrieval arm or some other docking interface, you can potentially use the craft to alter the trajectory of existing satellites
* Although the X-37B was launched on an expendable Atlas V rocket, the Air Force recently put out a solicitation for proposals for a first-stage Reusable Booster System utilizing a technique known as boost-back. With boost-back, after the booster boosts the payload and/or 2nd stage, it then does a 180 and boosts/glides back to a landing strip so that it can be easily reused. Lockheed Martin tested a secretive prototype of such a system (which they dubbed "Revolver") a couple years ago. If you combine such Reusable Boosters with a beefier successor to the X-37B, you have a rapid-launch reusable "surge" capability long desired by the Air Force. Such a surge capability could be useful when you need to quickly launch many satellites, such as when you need to deploy many satellites over a particular region in wartime or many of your satellites are knocked out by anti-satellite weapons or solar storms. Currently the Air Force has to wait for several weeks or months per satellite.
For anybody interested in watching video of the launch (a rather beautiful launch of the Atlas V rocket), you can find it here: http://www.youtube.com/watch?v=AdCpuv9RCwE
Also, for those who are interested in finding out more, there's a lot of good discussion with plenty of current and former space professionals (including some posts by Jim Oberg, the author of the submission article) over at this NASASpaceFlight.com thread on the X-37B: http://forum.nasaspaceflight.com/index.php?topic=21122.285