-
Minotaur IV Lite / HTV-2b - Aug 11, 2011
by
Liss
on 07 Aug, 2011 07:57
-
http://www.vandenberg.af.mil/news/story.asp?id=123266908Minotaur IV scheduled to launch August 10
Posted 8/5/2011 Updated 8/5/2011
8/5/2011 - A Minotaur IV rocket stands beside Space Launch Complex-8 here Wednesday, Aug. 3, 2011. The Minotaur IV will carry the HTV-2 scheduled to launch Aug. 10 between 7 a.m. and 1 p.m. (U.S. Air Force photo/SSgt Scottie McCord)
-
#1
by
Liss
on 07 Aug, 2011 08:09
-
Two NOTAMs found that may be related to the launch:
!CARF 08/043 (KZAK A3922/11) ZAK AIRSPACE DCC ON HTV2-BALLOON STATIONARY RESERVATION WITHIN AN AREA BNDD BY 3610N/13833W 3710N/13833W 3710N/14103W 3610N/14103W SFC-UNL WEF 1108071630-1108072300
!CARF 08/044 (KZAK A3937/11) ZAK AIRSPACE DCC ON HTV2-BALLOON STATIONARY RESERVATION WITHIN AN AREA BNDD BY 3159N/14532W 3259N/14532W 3259N/14755W 3159N/14755W SFC-UNL WEF 1108091000-1108091600
-
#2
by
Skyrocket
on 08 Aug, 2011 09:08
-
Just a little nitpicking:
It is a Minotaur IV Lite launch vehicle.
-
#3
by
Ronsmytheiii
on 10 Aug, 2011 03:45
-
-
#4
by
Ronsmytheiii
on 10 Aug, 2011 03:49
-
-
#5
by
Ronsmytheiii
on 10 Aug, 2011 03:56
-
-
#6
by
Ronsmytheiii
on 10 Aug, 2011 11:32
-
-
#7
by
Chris Bergin
on 10 Aug, 2011 12:23
-
-
#8
by
WulfTheSaxon
on 10 Aug, 2011 12:44
-
A quick attempt at removing some of the noise in that feed by averaging 1800 frames.
-
#9
by
Ronsmytheiii
on 10 Aug, 2011 12:45
-
-
#10
by
a_langwich
on 10 Aug, 2011 13:14
-
My understanding is that HTV-2 / Falcon is essentially unpowered after the boost phase, that it is testing flight control and aerodynamics at hypersonic regimes but not a power source (such as a scramjet). The hypersonic engine test was the Waverider / X-51 test which unfortunately hit a snag June 13.
Is this correct?
-
#11
by
MarekCyzio
on 10 Aug, 2011 13:25
-
I do not think X-51 "hit a snag" - the test was not successful, but not every test is successful and the failure did not stop the program.
HTV-2 is a glider - it has RCS engines, but no main engine.
-
#12
by
Ronsmytheiii
on 10 Aug, 2011 13:26
-
-
#13
by
kevin-rf
on 10 Aug, 2011 13:27
-
Thanks Chris, bit of a shame OSC does not have their own dedicated feed, but that is commercial operations for you.
Why? What value does Orbital or anyone gain for providing a live feed. Yes it gives some of us instant gratification, but that does not put additional rockets on the table for Orbital. One could argue that if anything, nothing should be broadcast about this test least others (cough, Iran) get ideas.
Reminds me of the following XKCD,
http://xkcd.com/932/
-
#14
by
Ronsmytheiii
on 10 Aug, 2011 13:29
-
Why? What value does Orbital or anyone gain for providing a live feed. Yes it gives some of us instant gratification, but that does not put additional rockets on the table for Orbital. One could argue that if anything, nothing should be broadcast about this test least others (cough, Iran) get ideas.
ULA thinks it is a good idea, and NRO does not mind launch coverage up to PLF sep.
-
#15
by
Ronsmytheiii
on 10 Aug, 2011 13:39
-
-
#16
by
Ronsmytheiii
on 10 Aug, 2011 13:52
-
WEll, looks like they took down the live feed from the pad
Edit: its back!
-
#17
by
William Graham
on 10 Aug, 2011 14:02
-
Scheduled T-0 has been and gone, rocket is still sitting there. Plenty of window left though.
-
#18
by
Ronsmytheiii
on 10 Aug, 2011 14:05
-
Scheduled T-0 has been and gone, rocket is still sitting there. Plenty of window left though.
Still waiting on weather
-
#19
by
WulfTheSaxon
on 10 Aug, 2011 14:28
-
weather conditions:
Somewhat surprised there’s no TDWR west of Las Vegas.
Edit: Oh, and another attempt at removing noise – this time with 4096 frames.
-
#20
by
Ronsmytheiii
on 10 Aug, 2011 14:31
-
while we wait, animated view of the flight profile:
-
#21
by
jjnodice
on 10 Aug, 2011 14:35
-
DARPA has released a lot more information prior to this flight compared to the first. I don't recall seeing STK videos prior to flight one.
-
#22
by
Ronsmytheiii
on 10 Aug, 2011 14:43
-
-
#23
by
Ronsmytheiii
on 10 Aug, 2011 14:47
-
-
#24
by
Ronsmytheiii
on 10 Aug, 2011 15:01
-
-
#25
by
Chris Bergin
on 10 Aug, 2011 15:05
-
How's the weather looking for tomorrow?
-
#26
by
Ronsmytheiii
on 10 Aug, 2011 15:17
-
includes todays forecast, but looks about the same for tomorrow:
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
555 AM PDT WED AUG 10 2011
.SYNOPSIS...
THE NIGHT THROUGH MORNING LOW CLOUD PATTERN WILL CONTINUE THROUGH
THE WEEK ALTHOUGH THE AMOUNT OF CLOUDS OVER THE VALLEYS WILL
DIMINISH AFTER THURSDAY. THERE WILL BE LITTLE CHANGE IN TEMPERATURES
THROUGH THE END OF THE WEEK. AFTERNOON HIGHS WILL RISE SOME OVER THE
WEEKEND AS HIGH PRESSURE BUILDS IN.
&&
.SHORT TERM (TODAY-FRI)... UPDATE FOR MENTION OF DRIZZLE...
MARINE LAYER IS NEAR 2300 FEET DEEP AND THE ONSHORE GRADIENTS ARE
ABOUT A ONE MB STRONGER BOTH TO THE NORTH AND THE SOUTH. THIS WILL
ALLOW CLOUDS TO COVER ALL THE COASTS AND VLYS AND SOME CLOUDS WILL
EVEN REACH THE SANTA CLARITA VLY. THIS ENHANCED MARINE LAYER WILL
BRING ANOTHER 1 TO 2 DEGREES OF COOLING ACROSS THE COASTS AND VLYS.
IT WILL ALSO BE ANOTHER DAY OF SLOW TO NONEXISTENT CLEARING ACROSS
THE BEACHES OF VENTURA AND SANTA BARBARA COUNTY. A SPOTTER REPORTED
DRIZZLE ACROSS A GOOD PORTION OF THE VENTURA COASTAL PLAIN THIS
MORNING...THEREFORE ADDED AREAS OF DRIZZLE ACROSS VENTURA COASTAL
ZONE. NO OTHER SITES HAVE REPORTED ANY DRIZZLE...THEREFORE NO
CHANGES EXPECTED FOR OTHER COASTAL ZONES. THE STRONG ONSHORE PUSH
WILL ALSO CREATE BREEZY CONDITIONS IN THE ANTELOPE VLY AND THROUGH W
TO E MTN PASSES SUCH AS THE SOLEDAD CANYON.
SYNOPTICALLY LITTLE CHANGES OF THE NEXT THREE DAYS. THE WEAK AND
FLAT WEST FLOW TILTS A LITTLE UP TO A SW TO NE DIRECTION AS THE
UPPER HIGH OVER AZ STRENGTHENS AND SHIFTS A LITTLE TO THE W. THIS
ALSO BUMPS UP HGTS AND THKNS SOME. THERE WILL NOT BE ANY BIG CHANGES
IN THE MARINE LAYER AND THERE WILL BE NIGHT THROUGH MORNING CLOUDS
ACROSS ALL THE COASTS AND MOST OF THE VLYS. PRESSURE GRADIENTS
SHOULD TREND OFFSHORE FRIDAY AND THIS SHOULD ALLOW FOR A LITTLE
BETTER CLEARING. MAX TEMPS WILL BUMP UP A DEGREE OR TWO EACH DAY
ACROSS THE INTERIOR WHILE COASTAL TEMPS WILL REMAIN ABOUT THE SAME
TODAY AND THURSDAY BUT WILL WARM SOME FRIDAY WITH THE OFFSHORE
TRENDS.
http://www.srh.noaa.gov/smg/SMG_prod.php?pil=AFD&sid=LOX&version=0
-
#27
by
rdale
on 10 Aug, 2011 15:37
-
I have zero California forecast experience, but the aviation outlook has thick dense fog in for tomorrow morning again.
-
#28
by
Chris Bergin
on 10 Aug, 2011 16:01
-
Copy that, thanks.
-
#29
by
Rocket Guy
on 10 Aug, 2011 16:29
-
-
#30
by
Ronsmytheiii
on 10 Aug, 2011 21:30
-
-
#31
by
STS-125
on 11 Aug, 2011 12:49
-
-
#32
by
Chris Bergin
on 11 Aug, 2011 14:00
-
T-45 minutes.
-
#33
by
Chris Bergin
on 11 Aug, 2011 14:25
-
No camera on the vehicle via the EELV portal, boooo.
T-20 minutes.
-
#34
by
Chris Bergin
on 11 Aug, 2011 14:31
-
DARPA:
T-16 minutes: “ALL STATIONS REPORT GO”
-
#35
by
STS-125
on 11 Aug, 2011 14:41
-
5 Minutes to launch
-
#36
by
Chris Bergin
on 11 Aug, 2011 14:44
-
T-60 seconds!
-
#37
by
Chris Bergin
on 11 Aug, 2011 14:46
-
LAUNCH!
-
#38
by
klausd
on 11 Aug, 2011 14:49
-
Yesterday they had a camera pointed on the vehicle. I dont understand why not today.
-
#39
by
STS-125
on 11 Aug, 2011 14:50
-
Fairing sep
-
#40
by
Chris Bergin
on 11 Aug, 2011 14:50
-
DARPA: Confirmation of a successful HTV2 separation from the Minotaur IV launch vehicle
-
#41
by
Chris Bergin
on 11 Aug, 2011 14:51
-
-
#42
by
STS-125
on 11 Aug, 2011 14:53
-
Acquisition of signal of HTV2 by Pacific Tracker.
-
#43
by
Chris Bergin
on 11 Aug, 2011 14:56
-
Mission is on track, entering glide phase
-
#44
by
jjnodice
on 11 Aug, 2011 14:59
-
Mission is on track, entering glide phase
Go baby go! (Sorry Chris, there is no HTV-2b cheerleading thread...)
-
#45
by
MarekCyzio
on 11 Aug, 2011 15:12
-
Mission is on track, entering glide phase
Still flying???
-
#46
by
Chris Bergin
on 11 Aug, 2011 15:14
-
No updates yet. Not sure if that's a good or bad sign. They were throwing out updates like crazy earlier.
-
#47
by
jjnodice
on 11 Aug, 2011 15:18
-
Should have impacted by now...
-
#48
by
jjnodice
on 11 Aug, 2011 15:22
-
After a long gap in tweets, there is this:
"Range assets have lost telemetry with #HTV2. More to follow"
-
#49
by
Chris Bergin
on 11 Aug, 2011 15:24
-
That could mean either a fail or EOM.
-
#50
by
jjnodice
on 11 Aug, 2011 15:25
-
Hopefully it is the latter!
-
#51
by
Rocket Science
on 11 Aug, 2011 15:38
-
Hope all went well for the team and maybe a video will show up sometime
-
#52
by
William Graham
on 11 Aug, 2011 15:47
-
That could mean either a fail or EOM.
It was posted shortly after nominal EOM, but there is not way of telling how long after LOS it was posted.
-
#53
by
Ronsmytheiii
on 11 Aug, 2011 16:28
-
Downrange assets did not reacquire tracking or telemetry. #HTV2 has an autonomous flight termination capability. More to follow.
http://twitter.com/#!/DARPA_News
-
#54
by
Chris Bergin
on 11 Aug, 2011 16:36
-
Sounds like a fail, but kinda need to hear that.
-
#55
by
jjnodice
on 11 Aug, 2011 16:53
-
Sounds like a fail, but kinda need to hear that.
Comm loss could have either been a comm system failure or a vehicle failure. Sounds like they didn't see it impact the planned location, therefore they are implying the vehicle was lost.
-
#56
by
Namechange User
on 11 Aug, 2011 16:57
-
Wow, it's on the main headline of the Drudge Report
-
#57
by
Chris Bergin
on 11 Aug, 2011 17:02
-
-
#58
by
rcoppola
on 11 Aug, 2011 17:02
-
I just hope they got enough telemetry to discern the faults.
-
#59
by
rdale
on 11 Aug, 2011 17:04
-
AP claim fail 
However they do say that their reporting consisted of nothing more than reading the DARPA tweets.
-
#60
by
Arthur
on 11 Aug, 2011 17:08
-
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."
-
#61
by
Lee Jay
on 11 Aug, 2011 17:16
-
Kinda goes to show just how difficult what Shuttle made look routine really was, especially on the first flight.
-
#62
by
rcoppola
on 11 Aug, 2011 17:17
-
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..
-
#63
by
jjnodice
on 11 Aug, 2011 19:37
-
-
#64
by
Ronsmytheiii
on 11 Aug, 2011 19:44
-
“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:
-
#65
by
jjnodice
on 11 Aug, 2011 19:52
-
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.
-
#66
by
hop
on 11 Aug, 2011 20:11
-
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.
-
#67
by
Rocket Science
on 11 Aug, 2011 20:24
-
-
#68
by
WulfTheSaxon
on 11 Aug, 2011 20:57
-
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.
-
#69
by
Phaldor
on 11 Aug, 2011 21:55
-
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.
-
#70
by
a_langwich
on 11 Aug, 2011 22:50
-
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.
-
#71
by
jjnodice
on 11 Aug, 2011 23:16
-
Very informative post "a_langwich". Thanks.
-
#72
by
robertross
on 11 Aug, 2011 23:26
-
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.
-
#73
by
Rocket Science
on 12 Aug, 2011 00:26
-
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
-
#74
by
jcm
on 12 Aug, 2011 02:21
-
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?
-
#75
by
Lee Jay
on 12 Aug, 2011 02:29
-
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.
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!
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!
-
#76
by
jjnodice
on 13 Aug, 2011 04:15
-
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.
-
#77
by
WulfTheSaxon
on 14 Aug, 2011 07:23
-
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).
-
#78
by
Lewis007
on 26 Aug, 2011 07:19
-
-
#79
by
Rocket Science
on 30 Aug, 2011 18:36
-
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.
-
#80
by
kch
on 30 Aug, 2011 18:49
-
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.
I'd wondered if the tailless-ness might be stealth-related -- makes sense. Of course, losing control and falling out of the sky isn't exactly stealthy ... nor, for that matter, is a daylight-visible plasma trail. Have to wonder what their options are at this point.
-
#81
by
kevin-rf
on 30 Aug, 2011 19:46
-
Huh?, the super heated ion trail it leaves in it's wake will negate any stealth technology it employs.
-
#82
by
Rocket Science
on 30 Aug, 2011 20:03
-
Stealth will vary at different parts of the flight regime. My comment was only at low mach velocities or exo-atmospheric. I guess unless we know the mission profile, all is spec. Maybe we can invite the chief designer in for a Q&A… Think he’ll take us up?
-
#83
by
kch
on 30 Aug, 2011 20:08
-
Stealth will vary at different parts of the flight regime. My comment was only at low mach velocities or exo-atmospheric. I guess unless we know the mission profile, all is spec. Maybe we can invite the chief designer in for a Q&A… Think he’ll take us up?
Somehow I doubt it ...
-
#84
by
kevin-rf
on 30 Aug, 2011 22:02
-
Think he’ll take us up?
Considering it is now Zero for Two, I think I'll pass on the ride
-
#85
by
WulfTheSaxon
on 31 Aug, 2011 03:18
-
Think he’ll take us up?
Considering it is now Zero for Two, I think I'll pass on the ride
Heh.
True, but remember they were both built before the first flight, so they couldn’t make many changes after the initial failure.
-
#86
by
Galactic Penguin SST
on 22 Apr, 2012 03:42
-
The accident investigation report is now out.
A technology demonstration and data-gathering platform, the HTV-2’s second test flight was conducted to validate current models and increase technical understanding of the hypersonic regime. The flight successfully demonstrated stable aerodynamically-controlled flight at speeds up to Mach 20 (twenty times the speed of sound) for nearly three minutes. Approximately nine minutes into the test flight, the vehicle experienced a series of shocks culminating in an anomaly, which prompted the autonomous flight safety system to use the vehicle’s aerodynamic systems to make a controlled descent and splashdown into the ocean.
“The initial shockwave disturbances experienced during second flight, from which the vehicle was able to recover and continue controlled flight, exceeded by more than 100 times what the vehicle was designed to withstand,” said DARPA Acting Director, Kaigham J. Gabriel. “That’s a major validation that we’re advancing our understanding of aerodynamic control for hypersonic flight.”
The ERB concluded that the “most probable cause of the HTV-2 Flight 2 premature flight termination was unexpected aeroshell degradation, creating multiple upsets of increasing severity that ultimately activated the Flight Safety System.”
Based on state-of-the-art models, ground testing of high-temperature materials and understanding of thermal effects in other more well-known flight regimes, a gradual wearing away of the vehicle’s skin as it reached stress tolerance limits was expected. However, larger than anticipated portions of the vehicle’s skin peeled from the aerostructure. The resulting gaps created strong, impulsive shock waves around the vehicle as it travelled nearly 13,000 miles per hour, causing the vehicle to roll abruptly. Based on knowledge gained from the first flight in 2010 and incorporated into the second flight, the vehicle’s aerodynamic stability allowed it to right itself successfully after several shockwave-induced rolls. Eventually, however, the severity of the continued disturbances finally exceeded the vehicle’s ability to recover.
http://www.darpa.mil/NewsEvents/Releases/2012/04/20.aspx
