Print 26 comment(s) - last by tng.. on Aug 14 at 6:56 PM

There were high expectations for DARPA's latest HTV-2 test flight, but the project seemingly has failed yet again

DARPA understood its latest test flight of the new hypersonic vehicle would cause an immense amount of pressure and stress on the actual HTV-2.  As such, there was still a large amount of disappointment when it was discovered DARPA lost contact with the HTV-2 vehicle this morning. 

The Hypersonic Technology Vehicle-2 successfully launched atop a Minotaur 4 rocket at 7:45 AM PST from Vandenberg Air Force Base.  Active vehicle testing is necessary because it provides better information than ground-based testing that simply cannot mimic actual tests.

The test flight was going as planned until the HTV-2 was supposed to enter glide phase, and that's when ground range technologies lost contact with the aircraft.  Ideally, the HTV-2 will one day be able to enter suborbital space, re-enter Earth's atmosphere, and then glide while collecting data at fast speeds.

DARPA tweeted the following message:  "Downrange assets did not reacquire tracking or telemetry. #HTV2 has an autonomous flight termination capability." 

DARPA plans to try and release as much information as possible, but wants to ensure it's accurate and an investigation already is underway. 

Researchers one day want the aircraft to hit an impressive Mach 20 traveling from Los Angeles to New York in a mere 12 minutes.

There was a significant amount of skepticism related to the DARPA effort, even though the amount of time in the air may have helped them collect more data.  However, the vehicle is designed to soar through the upper atmosphere before it splashed into the ocean about 4,000 miles from Vandenberg AFB.

DARPA previously launched an HTV-2 aircraft in April 2010 for a test flight, but it took just nine minutes before it was intentionally crashed because of significant technical failure.  However, the test reportedly reached speeds up to Mach 22 and communication/GPS was active despite the extremely fast 3.6 miles per second speed.

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Mach 20
By teldar on 8/11/11, Rating: 0
RE: Mach 20
By brandonicus on 8/11/2011 7:14:29 PM , Rating: 3
I think the issue is your understanding of the unit Mach.

RE: Mach 20
By DanNeely on 8/11/2011 7:18:43 PM , Rating: 3
Actually the problem is with your understanding. The speed of sound is not constant, it decreases with atmospheric pressure. At very high altitudes, like the edge of space, it's significantly lower than sea level. With a table expressing mach speed as a function of altitude you could determine approximately how high the test was conducted just by knowing that it was where mach22 = 13,000 mph.

RE: Mach 20
By michael2k on 8/11/2011 8:12:09 PM , Rating: 2
Well, with this:

You can probably deduce that it was in the stratosphere, since it was traveling approximately 591mph...

I doubt my math because if this is an air breathing rocket it must be within the mesosphere to operate at all, though I suppose it was going so fast that it might be scavenging enough oxygen to operate...

RE: Mach 20
By DanNeely on 8/11/2011 8:39:17 PM , Rating: 3
This is just a glider. Ultimately both knowing how to maneuver at mach 20 and a logn running mach 20 scram jet will be needed to make a deployable system but the research needed to complete both parts can be conducted independently. This project is working on the former part of the task. The X43 and X51 are both scram jet testbeds; and are slowly working up the speed/endurance thresholds for scramjets.

RE: Mach 20
By Natch on 8/12/2011 8:02:05 AM , Rating: 3
Do they have a test pilot named Steve Austin?? ;)

RE: Mach 20
By benny638 on 8/12/2011 10:54:01 AM , Rating: 2
An an Aerospace Engineer I sure am glad someone pointed out the fact that the speed of sound, which is defined as a = SQRT(gamma*R*T) where gamma is the calorically perfect value of the ratio of specific heats and R is the gas constant for air and T is the static temparture, is not constant as it varies with Tempartue/pressure which can be shown using the ideal gas law PV=NkT. My god I acutually remember. :-)

RE: Mach 20
By tng on 8/14/2011 6:55:35 PM , Rating: 3
Researchers one day want the aircraft to hit an impressive Mach 20
Reading comprehension...

Mach 20 is the goal, not necessarily what they hit on this flight.

RE: Mach 20
By tng on 8/14/2011 6:56:41 PM , Rating: 2
OK, My bad....

Lost contact?
By 2ManyOptions on 8/11/2011 10:47:50 PM , Rating: 2
So how do they know where this is going to crash/land/terminate, since they have lost contact with it?

RE: Lost contact?
By DanNeely on 8/11/2011 11:59:23 PM , Rating: 3
Lost contact refers to the on board transmitter; not the radar systems that are also tracking.

RE: Lost contact?
By geddarkstorm on 8/12/2011 2:26:24 PM , Rating: 2
True indeed. From what I've read, the craft reached Mach 20 and crashed into the Pacific where it was supposed to. Why communications keep being lost after 9 minutes (both this attempt and the previous attempt lost contact at the 9 minute mark) is curious. This is the mark where the craft enters aerodynamic mode and starts maneuvering into Mach 20. Potentially suggests some sort of plasma buildup blocking coms.

RE: Lost contact?
By JediJeb on 8/12/2011 3:01:07 PM , Rating: 2
Or could it be at that point it encounters some massive turbulence which has not been accounted for in the design and it is simply shaking the transmitters apart?

Dr. Evil
By fic2 on 8/11/2011 6:11:32 PM , Rating: 2
And Dr. Evil again proves how easy it is to acquire super ultra sonic aircraft from his secret island hideaway.

RE: Dr. Evil
By lightfoot on 8/11/2011 6:51:06 PM , Rating: 2
But do they come with "lasers?"

RE: Dr. Evil
By Gondor on 8/12/2011 4:00:53 AM , Rating: 2
Giant ones.

By ShaolinSoccer on 8/12/2011 12:07:11 AM , Rating: 5
Maybe it was a successful flight and they are just telling the world that it wasn't because conspiracies are so much cooler lol

Or maybe aliens said "hell no"...

I need to get a life...

Ionization Blackout
By lightfoot on 8/11/2011 5:57:11 PM , Rating: 2
Is it possible that they lost communication with the vehicle due to an ionization blackout? Or are they somehow compensating for this well documented effect?

RE: Ionization Blackout
By DanNeely on 8/11/2011 6:51:50 PM , Rating: 2
They maintained contact with the first flight body for 9 minutes; so they clearly have a way around the problem. Whether it was the failure point, or if something else was is TBD.

By JimboK29 on 8/12/2011 9:11:13 AM , Rating: 2
The cause was most likely dynamic pressure post max-q with vort max transients. Aerodynamic transient response - and the methods to control it is a tricky science. At those speeds, sampled value interpretation is logarithmic and the algorithms to deal with them is not a trivial task. It is also worth noting aerodynamic drag increases by 4 for every double in speed.

Project failed
By puplan on 8/12/2011 9:27:10 PM , Rating: 2
The test partially failed or partially succeeded (pick your angle). Useful data was collected. Project did not fail. Most successful projects consist of many failed tests. Welcome to the real world.

High Speed Flops
By Super Speed Train on 8/11/11, Rating: -1
RE: High Speed Flops
By Pirks on 8/11/11, Rating: -1
RE: High Speed Flops
By c4xp on 8/12/2011 7:55:43 AM , Rating: 1
But then how will they keep technical advantage over other 'unfriendly' countries ?

Trains do not win wars.. Plains do

RE: High Speed Flops
By Schrag4 on 8/12/2011 10:42:42 AM , Rating: 2
Trains do not win wars.. Plains do

Yes, big, open, rolling plains. I suppose you gotta grow food somewhere to feed your army?

RE: High Speed Flops
By Bostlabs on 8/12/2011 11:33:00 AM , Rating: 3
But of course! Everyone knows that.
Either that or you have several scavenger vehicles running around getting ore...

"The whole principle [of censorship] is wrong. It's like demanding that grown men live on skim milk because the baby can't have steak." -- Robert Heinlein
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