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DARPA confirms splash down of HTV-2 hypersonic vehicle on second test flight


August 23, 2011

DARPA's HTV-2 hypersonic vehicle, which splashed down in the Pacific Ocean during its second test flight

DARPA's HTV-2 hypersonic vehicle, which splashed down in the Pacific Ocean during its second test flight

DARPA has confirmed the splash down of its unmanned Falcon Hypersonic Technology Vehicle (HTV-2) following the hypersonic vehicle's second test flight on August 11. While a "controlled descent" generally refers to a human directing and guiding an aircraft to an unscheduled landing, safety systems onboard the HTV-2 kicked in after an anomaly was detected a little over nine minutes into the test flight and autonomously directed it into the ocean.

"We've confirmed that the HTV-2 made impact with the Pacific Ocean along its flight trajectory as planned in the event of an anomaly," explained Air Force Maj. Chris Schulz, DARPA HTV-2 program manager and PhD in aerospace engineering. "This flight safety system is a significant engineering advance in that the system prompts a vehicle to monitor the parameters under which it is operating and exercise safety protocols completely autonomously should those parameters be breached."

DARPA says that changes made to the vehicle following the first test flight, which also ended with a controlled descent into the Pacific, appear to have been effective and aren't being blamed for the anomaly detected during the second test flight. These changes include adjusting the HTV-2's center of gravity, decreasing the angle of attack and using the onboard reaction control systems to augment vehicle flaps during the second test flight.

"According to a preliminary review of the data collected prior to the anomaly encountered by the HTV-2 during its second test flight," said DARPA Director Regina Dugan, "HTV-2 demonstrated stable aerodynamically controlled Mach 20 hypersonic flight for approximately three minutes. It appears that the engineering changes put into place following the vehicle's first flight test in April 2010 were effective. We do not yet know the cause of the anomaly for Flight 2."

Having successfully separated from the Minotaur IV launch vehicle and transitioned to Mach 20 flight on the second test flight, the anomaly appears to have occurred as the HTV-2 attempted to enter the glide phase of flight. DARPA says an independent Engineering Review Board will attempt to identify the most probable cause of the latest anomaly over the coming weeks.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

This will make finding out what went wrong easier.


While I think that the biggest use of scramjets will be to lower the cost of orbital insertion, if they get the thing to fly reliably it could be safer than trying to negotiate the scrapyard we call LEO.


Anomaly: failure Controlled impact with Pacific Ocean: Controlled Crash

It failed in flight and crashed into the Pacific. Period.


These things are two expensive for them to be freaking out over every little anomaly. My car doesn\'t go \"low pressure detected in tire... steering into a ditch!\" :-)

If it was heading towards land/populated area that\'s one thing, but if they crash it every time it doesn\'t work as expected... well, there\'s a lot of things they still don\'t understand about flight under these conditions, so that\'s going to be a lot of crashes. And then I\'m going to be tempted to don a snorkel and go diving for souvenirs. ;-)


Am glad it hit the Pacific Ocean after the \"anomaly\"...

Jolene Torgler

The most important thing is that they can recover it and look at the flight data. If it was an uncontrolled descent, they would have lost it and the data. You have to understand that this device is traveling well outside of known conditions. The fact that is was able to maintain Mach 20 for 3 minutes is really amazing. This is what R&D is all about.


here\'s a way to travel 5,000 miles per hour without fuel. go up into space, or build a vaccum-tube and send maglev bullet pods through it.

Facebook User

Well, the article didn\'t tell us as much as they know at this point. However, they may learn more after the mishap recovery. Also, there surely is much data to analyse yet. I used to analyse 1553 flight test data, and often the original cause can be found. The emergency ditch system obviously worked well. In breaking new ground as they are here, it does seem they are making progress. It would have been nice if it has been a complete success, but I\'m sure they\'ll uncover what ever the cause was and overcome it.

Ed D

Well , it would certainly make an idea propulsion system for sending warheads to an unfortunate receiver across the world somewhere. Just think of the \"cost savings\" of using these for armament or ordinance from anywhere in the world , being launched with the assist of a booster rocket or launched from another craft pretty much undetected. There would be no purpose to send our military anywhere , just bomb them from an anonymous place. It flies so high in the atmosphere where there is virtually no air , so therefore not much of a sound that would be detectable from the ground at all or no acoustic signature to detect. About the only way it could even be detected flying up there is from the exhaust infra-red signature just like a stealth plane. Of course if it was flying at mach 20 , there would not be much anyone could do about it anyway .

Jim Andrews

I think the case is that what is left after the flight is an empty biscuit tin with a pointy end and a hand full of onboard instruments and sensors.

When they fly, all the relevant data is gathered and what hits the water is just scrap - not worth collecting or caring about.

This time tho - rather than have it go into a plain crash and smash into the ocean, they were able to modify the design into being a self stabilising and landable configuration - all steps in the process of designing fast and reusable air craft.

Mr Stiffy

My,my what flowery words- \"Crash landing\" just doesn\'t sound as nice!

Can\'t they just admit that it\'s failed rather quickly twice in a row?

How long was the full flight intended to be?


Theres no historical perspective on the velocity achievd = MACH 20, it sounds like an elevated accomplishment, in it\'s own right !. s.

Søren Algreen-ussing

The HTV-2 was probably intended to be landed in the ocean at the end of a fully successful flight so if it went into the water in a controlled manner it can not really be considered a crash.


Judging by the lack of scientific knowledge, there must be a lot of teabaggers in here.

Jeddy, how do you propose to get to space without fuel, or build vacuum tubes and shoot maglev bullet pods (wtf they are)? Oh, I forgot, you jes use \'lectric, that don\'t need no fuel...

I worked on HTV-1. The object of the test is to attain hypersonic speeds with air breathing propulsion system. Landing was never in plan 1 or 2 (paragraph 3 \"controlled descent into the Pacific\"). The entire craft is less than 30 feet long, essentially a titanium tank of highly pressurized fuel. At this point, there is no room for landing gear, nor a need to develop one that won\'t melt off when you deploy it at mach 20.

Max Orbit

Wow Mach 20! So by the time you hear it you\'ll have been dead half an hour! Wonder who the \"enemy\" will be by the time it\'s ready?

Michael Oberhofer

at mach 20 you\'d have a job getting it to go anywhere other than straight on. If you wanted to turn it or pitch it down toward a target on the earth you\'d have to slow it down quite a lot. mach 20 isn\'t much slower than orbital velocity.

it would also be pretty easy to track given that the outside skin will be glowing at 2000 degrees centigrade, so what\'s the point of the stealthy shape?


Re mommus

The shape was chosen purely for aerodynamic reasons. Although at the speed it flies plasmadynamic might be a better name for it.


If it is known why there was a failure, then it's not a failure at all. Just another step in a long proccess. If you don't think so, please learn about Thomas Edison's journey towards a sustainable lightbulb. Hundreds of "failures", albeit he refered to it something like "separating what works from what doesn't".

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