[Launch Alert] Launch Follow-up

[Launch Alert]

                             LAUNCH ALERT
 				  
                              Brian Webb
                     Ventura County, California
                  launch-alert-editor at earthlink.net
                        www.spacearchive.info
		       
                               2011 August 13 (Saturday) 18:54 PDT
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                 MINOTAUR IV/HTV-2 LAUNCH FOLLOW-UP

Last Thursday, a Minotaur IV Lite booster carrying the HTV-2 aircraft
was launched from Vandenberg AFB. Although the launch appeared to be
successful, contact was later lost with the unmanned HTV-2.

This issue of Launch Alert presents additional information about the
flight along with an observation of the launch.

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        DARPA HYPERSONIC VEHICLE ADVANCES TECHNICAL KNOWLEDGE
  HTV-2 collects unique data during several phases of second flight
       Defense Advanced Research Projects Agency News Release
                         2011 August 11

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. The second test flight began with
launch at 0745 Pacific Time. The Minotaur IV vehicle successfully
inserted the aircraft into the desired trajectory. Separation of the
vehicle was confirmed by rocket cam and the aircraft transitioned to
Mach 20 aerodynamic flight. This transition represents a critical
knowledge and control point in maneuvering atmospheric hypersonic
flight. More than nine minutes of data was collected before an anomaly
caused loss of signal. Initial indications are that the aircraft
impacted the Pacific Ocean along the planned flight path.

"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."

"Prior to flight, the technical team completed the most sophisticated
simulations and extensive wind tunnel tests possible. But these
ground tests have not yielded the necessary knowledge. Filling the
gaps in our understanding of hypersonic flight in this demanding
regime requires that we be willing to fly," said DARPA Director
Regina Dugan. "In the April 2010 test, we obtained four times the
amount of data previously available at these speeds. Today more than
20 air, land, sea and space data collection systems were operational.
We'll learn. We'll try again. That's what it takes."

According to Schulz, three technical challenges exist within this
HTV-2 flight regime.  They are categorized as aerodynamic;
aerothermal; and guidance, navigation and control.  And each phase of
flight introduces unique obstacles within these areas. 

"To address these obstacles, DARPA has assembled a team of experts
that will analyze the flight data collected during today's test
flight, expanding our technical understanding of this incredibly harsh
flight regime," explained Schulz.  "As today's flight indicates,
high-Mach flight in the atmosphere is virtually uncharted territory. "

In the coming weeks, the assembled independent Engineering Review
Board will review and analyze the data collected. This data will
inform policy, acquisition and operational decisions for future
Conventional Prompt Global Strike programs-the goal of which,
ultimately, is to have the capability to reach anywhere in the world
in less than one hour.

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                         LAUNCH OBSERVATION

Despite Launch Alert's large number of readers, only one person
reported seeing Thursday's Minotaur IV Lite/HTV-2 launch.

Stan wrote:

"Saw the launch Thursday morning from east of Morgan Hill, CA - in the
hills at an elevation of 2,000 ft.  Saw the contrail rising in the S/W
morning sky, and watched the rocket climb into the sky and then
disappear. Was able to see the the rocket for approximately one
minute. The trail looked like the contrail from a jet, except it was
traveling in the wrong direction and very fast!! Love seeing those
rocket launches..."

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