And then there were none. The fourth and final X-51A Waverider hypersonic plane will be tested next spring or summer, the U.S. military announced Wednesday.
The third unmanned, experimental plane failed to fly last August after being dropped from a B-52 bomber off the coast of California near Point Mugu.
Prior to plummeting into the Pacific Ocean, the one-time-use, Boeing-built bullet was supposed to shoot through the sky for five minutes in an attempt to reach Mach 6, or 3,600 mph, or six-times the speed of sound.
Instead, a fault in the control fin caused the craft to lose balance and crash off the coast before activating its supersonic combustion ramjet (scramjet) engine. An investigation has ruled out software issues or power failures as the cause.
The AP reports that while the exact reason for the failure has not been identified, signs point to a "random vibration issue," according to program manager Charlie Brink at the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio.
And then there was one.
At six times speed of splash, an unmanned, experimental hypersonic plane failed to fly after being dropped by a B-52 bomber Tuesday off the coast of California near Point Mugu.
Before bailing into the Pacific Ocean, the Boeing-built bullet was supposed to shoot through the sky for five minutes in an attempt to reach Mach 6, or 3,600 mph, or six times the speed of sound.
However, for reasons unknown, a fault in the X-51A Waverider's control fin prevented the supersonic combustion ramjet (scramjet) engine from lighting, and that was the end of that.
"X-51A flight ends prematurely" reads Wednesday's official Air Force statement:
The X-51A Waverider successfully launched from an Air Force B-52 bomber over Point Mugu Naval Air Warfare Center Sea Range Aug. 14 at approximately 11:36 a.m. PST.
The X-51 safely separated from the B-52 and the rocket booster fired as planned. However after 16 seconds, a fault was identified with one of the cruiser control fins. Once the X-51 separated from the rocket booster, approximately 15 seconds later, the cruiser was not able to maintain control due to the faulty control fin and was lost.
An artist's rendition of the Falcon Hypersonic Technology Vehicle 2 developed by the Defense Advanced Research Projects Agency.
When they're not testing gigapixel-class cameras or putting robots on treadmills, the Defense Advanced Research Projects Agency is hard at work on a hypersonic glider with the ablity to travel over 13,000 miles per hour and carry out a military strike anywhere in the world in less than 60 minutes.
DARPA, the DoD's research arm with the motto "Creating & Preventing Strategic Surprise," announced Friday that it will be seeking proposals next month to help solve tech hurdles in the hypersonic X-plane. The new phase of the program reflects the agency's goal of testing a full-scale hypersonic X-plane in four years.
On August 14, researchers will host a so-called Proposers' Day, and address specifics about which technical areas are seeking proposals.
Experimental versions of the rocket-launched unmanned glider have already been tested. The craft, designed to fly at speeds 20 times the speed of sound (Mach 20), requires extraordinary controls and has to endure blast-furnace heat.