Military Aircraft Hit Mach 20 Before Ocean Crash, DARPA Says

Re:Military Aircraft Hit Mach 20 Before Ocean Crash, DARPA Says by 51Cards on Thursday March 28, 2013 @09:13AM (#5454557)

August 18th, 2011? Possibly a few tests after this have already happened?

Edit: Looks like no third flight yet. Found this followup: http://www.darpa.mil/threeColumn.aspx?pageid=2147485247

Also found this paragraph to be interesting:

“The initial shockwave disturbances experienced during second flight, from which the vehicle was able to recover and continue controlled flight, exceeded by more than 100 times what the vehicle was designed to withstand,” said DARPA Acting Director, Kaigham J. Gabriel.

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Re:Military Aircraft Hit Mach 20 Before Ocean Crash, DARPA Says by akavel on Thursday March 28, 2013 @09:32AM (#5454636)

And this: "[G]radual wearing away of the vehicle’s skin as it reached stress tolerance limits was expected. However, larger than anticipated portions of the vehicle’s skin peeled from the aerostructure."

And, dated: April 20, 2012

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Re:Military Aircraft Hit Mach 20 Before Ocean Crash, DARPA Says by iandh on Thursday March 28, 2013 @10:30AM (#5454934)

The "gradual wearing of the vehicle's skin" is called is called ablation.

Its a standard way both hyper sonic and reentry vehicles manage heat. Basically the skin boils off creating a pressure wave that the vehicle flights behind.

Wikipedia has a good description of it. http://en.wikipedia.org/wiki/Atmospheric_reentry#Ablative

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