Author Topic: Minotaur IV Lite / HTV-2b - Aug 11, 2011  (Read 58280 times)

Offline Arthur

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #60 on: 08/11/2011 05:08 pm »
AP update:

"The first HTV-2 was launched on April 22, 2010. It returned nine minutes of data, including 139 seconds of aerodynamic data at speeds between 17 and 22 times the speed of sound, DARPA said.

That craft detected an anomaly, aborted its flight and plunged into the ocean, the agency said."
« Last Edit: 08/11/2011 05:09 pm by Arthur »

Offline Lee Jay

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #61 on: 08/11/2011 05:16 pm »
Kinda goes to show just how difficult what Shuttle made look routine really was, especially on the first flight.

Offline rcoppola

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #62 on: 08/11/2011 05:17 pm »
I wonder just how small they designed the anomaly threshold with regards to the autonomous destruct. It would be a shame if the anomaly could have been overcome if given the falcon enough time to respond before auto destruct. But who knows, better safe then sorry I guess..
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Offline jjnodice

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #63 on: 08/11/2011 07:37 pm »
And here's some official news:

http://www.darpa.mil/NewsEvents/Releases/2011/2011/08/11DARPA_HYPERSONIC_VEHICLE_ADVANCES_TECHNICAL_KNOWLEDGE.aspx

Sounds like it failed in the same regime as last year's flight...

Offline Ronsmytheiii

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #64 on: 08/11/2011 07:44 pm »
Quote
“Here’s what we know,” said Air Force Maj. Chris Schulz, DARPA HTV-2 program manager and PhD in aerospace engineering.  “We know how to boost the aircraft to near space.  We know how to insert the aircraft into atmospheric hypersonic flight.  We do not yet know how to achieve the desired control during the aerodynamic phase of flight.  It’s vexing; I’m confident there is a solution. We have to find it.”

These two craft did not seem to have that issue:


Offline jjnodice

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #65 on: 08/11/2011 07:52 pm »

These two craft did not seem to have that issue:


Agreed!  They did not seem to be "vexed" like this vehicle.  I didn't like the spin in the press release.

Offline hop

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #66 on: 08/11/2011 08:11 pm »
These two craft did not seem to have that issue:
Agreed!  They did not seem to be "vexed" like this vehicle.  I didn't like the spin in the press release.
Apples and oranges.

Offline Rocket Science

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #67 on: 08/11/2011 08:24 pm »
« Last Edit: 08/11/2011 10:05 pm by Rocket Science »
"The laws of physics are unforgiving"
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Offline WulfTheSaxon

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #68 on: 08/11/2011 08:57 pm »
Sounds like it failed in the same regime as last year's flight...

I wonder how its chances would have been if they hadn’t already built it before the first test… Hopefully the next one fares better, assuming there is a next one.

Offline Phaldor

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #69 on: 08/11/2011 09:55 pm »
These two craft did not seem to have that issue:
Agreed!  They did not seem to be "vexed" like this vehicle.  I didn't like the spin in the press release.
Apples and oranges.
I think you're right, but I will probably be corrected.  The space shuttle for sure is different than this vehicle, it was designed to only glide at that speed, not bank, pitch, and yaw until it slowed WAY down prior to landing.  This vehicle appears to have been designed to test the manuvering capabilities while at speed, and that is a whole different ball game.

Offline a_langwich

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #70 on: 08/11/2011 10:50 pm »

These two craft did not seem to have that issue:


Agreed!  They did not seem to be "vexed" like this vehicle.  I didn't like the spin in the press release.


The difference is that the shuttle and the X-34 drop like rocks, trying to get through and get out of the hypersonic region as quickly as reasonable.  The HTV-2 is trying to solve problems and answer questions the shuttle (wisely) avoided and punted down the road.

In the hypersonic regime, the shuttle's lift/drag is 1.  As I recall, the HTV-2 L/D was around 3, and the HTV-3 was planned to be near 5.  This extra lift produces more control challenges, as does having to react rather quickly to situations at Mach 20.  The aerothermal challenges you can easily see just by looking at the sharp edges of the design.   

The changes made from HTV-2a to HTV-2b seemed to be largely addressing possible problems in the control system, but as far as I know thermal problems were never ruled out.

In a way, it's sad that we flew the shuttle for thirty years and learned so little about the hypersonic region.  Probably another manifestation of the extremely tight margins, in budget and safety, left beyond just getting the job done.  The boundary layer trip experiments were a great idea, I thought, but just one set of experiments.  Perhaps the X-34 can improve this, but it seems mostly designed as a school bus for on-orbit experiments.

The links to ASSET are fascinating, thanks for sharing those.

Offline jjnodice

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #71 on: 08/11/2011 11:16 pm »
Very informative post "a_langwich".  Thanks.

Offline robertross

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #72 on: 08/11/2011 11:26 pm »
This was getting quite a bit of attention on CNN this evening. Strangely enough, it was mostly positive spin on future capabilities with military & civilian uses.

Offline Rocket Science

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #73 on: 08/12/2011 12:26 am »
We don’t know what caused the problems but given the maneuvers to be investigated “coupling” could have been a concern given the vehicle “tailless” configuration. All speculation of course. Makes for some good reading from a historical perspective.
Regards
Robert
http://www.nasa.gov/centers/dryden/pdf/88484main_H-2106.pdf
« Last Edit: 08/12/2011 12:27 am by Rocket Science »
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator

Offline jcm

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #74 on: 08/12/2011 02:21 am »
Too bad... hope they got enough telemetry.
I haven't seen any discussion of apogee / altitude range - sounds like 100 km or
so, but does anyone have info?
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Offline Lee Jay

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #75 on: 08/12/2011 02:29 am »
Quote
Today, DARPA attempted to fly the fastest aircraft ever built.  The Agency’s Falcon Hypersonic Technology Vehicle 2 (HTV-2) is designed to fly anywhere in the world in less than 60 minutes.  This capability requires an aircraft that can fly at 13,000 mph, while experiencing temperatures in excess of 3500F.

Okay, I thought Shuttle was the fastest aircraft ever built.

Quote
The second test flight began with launch at 0745 Pacific Time.  The Minotaur IV vehicle successfully inserted the aircraft into the desired trajectory.

Congrats to Orbital!

Quote
Separation of the vehicle was confirmed by rocket cam and the aircraft transitioned to Mach 20 aerodynamic flight.

Okay, DARPA, L2 is thataway, let's see that rocket cam video!   :D
« Last Edit: 08/12/2011 02:29 am by Lee Jay »

Offline jjnodice

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #76 on: 08/13/2011 04:15 am »
We don’t know what caused the problems but given the maneuvers to be investigated “coupling” could have been a concern given the vehicle “tailless” configuration. All speculation of course. Makes for some good reading from a historical perspective.
Regards
Robert
http://www.nasa.gov/centers/dryden/pdf/88484main_H-2106.pdf

So why go tailless?  Shuttle and X-37 have them.  Would a tail be an obstacle in reaching the L/D goals at the expense of more difficult control?  Or is the tail more important for a vehicle that wants to go subsonic at some point?  Just curious and wanting to learn more.

Offline WulfTheSaxon

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #77 on: 08/14/2011 07:23 am »
Quote
Today, DARPA attempted to fly the fastest aircraft ever built.  The Agency’s Falcon Hypersonic Technology Vehicle 2 (HTV-2) is designed to fly anywhere in the world in less than 60 minutes.  This capability requires an aircraft that can fly at 13,000 mph, while experiencing temperatures in excess of 3500F.
Okay, I thought Shuttle was the fastest aircraft ever built.

That’s wrong on multiple levels. First, the SR-71 Blackbird is still generally recognized as the fastest “aircraft” ever built, at Mach 3.3. As far as speeds attained during atmospheric reentry, the Shuttle does indeed beat the HTV-2, at around Mach 23.

The Apollo CM was faster than that (Mach 30), but it qualifies even less than the Shuttle, having a lift-to-drag ratio of just 0.368 (versus the Shuttle’s 1 and a flying squirrel’s 1.98).

Offline Lewis007

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #78 on: 08/26/2011 07:19 am »
DARPA has released a video showing the HTV-2b in flight, flying at Mach 20.

For more info, see http://www.space.com/12739-video-hypersonic-military-aircraft-flight-darpa-htv2.html


Offline Rocket Science

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Re: Minotaur IV Lite / HTV-2b - Aug 11, 2011
« Reply #79 on: 08/30/2011 06:36 pm »
We don’t know what caused the problems but given the maneuvers to be investigated “coupling” could have been a concern given the vehicle “tailless” configuration. All speculation of course. Makes for some good reading from a historical perspective.
Regards
Robert
http://www.nasa.gov/centers/dryden/pdf/88484main_H-2106.pdf

So why go tailless?  Shuttle and X-37 have them.  Would a tail be an obstacle in reaching the L/D goals at the expense of more difficult control?  Or is the tail more important for a vehicle that wants to go subsonic at some point?  Just curious and wanting to learn more.
At hypersonic speeds appendages are high heat areas especially if the vehicle spends a lot of its time in the denser atmosphere.  They may also be considering the stealth ability in a tailless configuration in a military application.
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator

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