After seven months of examining data from the hypersonic HTV-2 vehicle that was lost during a test flight over the Pacific last August, DARPA says it has zeroed in on the vehicle’s skin, and its inability to withstand the stresses of incredibly fast speeds, as the source of the malfunction.
According to DARPA’s report, ground testing and thermal modeling that dictated the vehicle’s skin structure needs was completed based on extrapolations from known flight characteristics, and ultimately proved unable to “successfully predict the harsh realities of Mach 20 atmospheric flight.”
Those harsh realities took their toll on HTV-2’s aeroshell as the vehicle traveled around the 13,000 mph mark, creating gaps in the vehicle’s surface that triggered impulsive shock waves around the 13,000 mph mark, approximately 9 minutes after the vehicle successfully separated from a rocket in the upper atmosphere.
While HTV-2 was initially able to recover from the abrupt rolling induced by the waves, the vehicle eventually succumbed to the disturbances and made a controlled descent into the Pacific.
Before the malfunction, HTV-2 was able to maintain controlled flight at Mach 20 – a speed that could conquer the distance spanning L.A. and New York in less than 12 minutes – for three minutes.
DARPA says it will move forward with the “profound advancement of understanding” gleaned from the failed flight and continue to work toward its ultimate goal of creating a vehicle that could travel anywhere in the planet in less than 60 minutes.
Check out footage of the failed flight below.
To get a better idea of just how fast the HTV-2 traveled, check out this video as well.