[meteorite-list] crusing for a brusing

From: Greg Redfern <gredfern_at_meteoritecentral.com>
Date: Thu Mar 31 07:58:01 2005
Message-ID: <000601c535f1$46e63690$110110ac_at_DHRYBX21>

Mark, List

One correction to my original post....P/Tempel 1's magnitude will go from 9
to 6, not 6 to 3.

My apologies.

Greg

Greg Redfern
JPL NASA Solar System Ambassador
http://www.jpl.nasa.gov/ambassador/index.html
International Meteorite Collectors Association #5781
http://www.imca.cc
Member Meteoritical Society
http://www.meteoriticalsociety.org/

-----Original Message-----
From: meteorite-list-bounces_at_meteoritecentral.com
[mailto:meteorite-list-bounces_at_meteoritecentral.com] On Behalf Of Greg
Redfern
Sent: Wednesday, March 30, 2005 11:38 PM
To: 'mark ford'; meteorite-list_at_meteoritecentral.com
Subject: RE: [meteorite-list] crusing for a brusing

Dear Mark & List,

   I have had the pleasure of interviewing some of the Deep Impact (DI)
Mission scientists, including the Principal Investigator, Dr. Michael
A'Hearn, at the University of Maryland UMD).

   I also co-authored with Elizabeth Warner, UMD DI Team Member and Director
of the UMD Observatory a cover story on DI for the June 2005 issue of Sky &
Telescope Magazine.

  Finally, I give presentations to the public on DI in my capacity as a NASA
JPL Solar System Ambassador.

  The comments that follow are my own and not attributable to the DI Team,
UMD or NASA. They are based on the results of my interviews and research.

  There is very little chance of Comet P/Tempel 1 being completely shattered
because this is a very large body that will experience the equivalence of
4.8 tons of TNT upon impact. The resultant crater is expected to be the size
of a football stadium and perhaps 100 feet deep. Of course this will be
dependant upon the density, porosity and tensile strength of the comet. This
is precisely why DI was conceived, authorized, built and launched - to
conduct an experiment designed to determine these physical parameters.

DI will give us data to determine these physical characteristics PLUS see
inside a cometary body for the first time in history. We have seen the
nuclei of several comets but never an interior. We will also be able to
observe the results of the impact - will a new release of pristine cometary
material occur, will there be a new "jet" formed? DI has a professional and
amateur observation program in place to help observe P/Tempel 1 before,
during, and after impact. These programs will provide valuable data and are
an integral part of the DI mission.

The comet is expected to go from magnitude 6 to 3, and your geographical
location determines whether you will see the comet at impact. Hawaii has the
best US view while in the majority of the US the comet will have set.

If you have more questions please feel free to email me and check out the DI
website: http://deepimpact.jpl.nasa.gov/.

All the best,

Greg



Greg Redfern
JPL NASA Solar System Ambassador
http://www.jpl.nasa.gov/ambassador/index.html
International Meteorite Collectors Association #5781
http://www.imca.cc
Member Meteoritical Society
http://www.meteoriticalsociety.org/

-----Original Message-----
From: meteorite-list-bounces_at_meteoritecentral.com
[mailto:meteorite-list-bounces_at_meteoritecentral.com] On Behalf Of mark ford
Sent: Wednesday, March 30, 2005 3:00 AM
To: meteorite-list_at_meteoritecentral.com
Subject: RE: [meteorite-list] crusing for a brusing


Hi,

I heard a rumour, that some of the mission scientists who devised the
Deep impact's copper projectile (that will impact the comet), may have
completely misinterpreted the mean density of the comet, and there is a
very real possibility that it may actually completely shatter the comet
into several pieces!!

Apparently they made quite a few educated guesses since not a great deal
is known about the physical structure of the material.

The other interesting thing is that the change in the dust trail from
the comet should be quite pronounced, so amateurs may be able to
actually observe the impact using telescopes!

Should be fun!

Best
Mark Ford




-----Original Message-----
From: Darren Garrison [mailto:cynapse_at_charter.net]
Sent: Monday, March 28, 2005 4:50 AM
To: Meteorite-list_at_meteoritecentral.com
Subject: [meteorite-list] crusing for a brusing

Or crusing TO a brusing, if you will.

http://www.nasa.gov/home/hqnews/2005/mar/HQ_05086_deep_impact.html


Dolores Beasley
Headquarters, Washington
(Phone: 202/358-1753)

D.C. Agle
Jet Propulsion Laboratory, Pasadena, Calif.
(Phone: 818/ 393-9011)


 March 25, 2005
RELEASE: 05-086

 
NASA Releases Deep Impact Mission Status Report

NASA's Deep Impact spacecraft completed the commissioning phase of the
mission and has moved into
the cruise phase.

Deep Impact mission planners have separated the spacecraft's flight
operations into five mission
phases. Cruise phase will continue until about 60 days before the
encounter with comet Tempel 1 on
July 4, 2005.

Soon after launch on Jan. 12, 2005, Deep Impact entered the
commissioning phase. During that phase,
the mission team verified the basic state of health of all subsystems
and tested the operation of
science instruments. The spacecraft's autonomous navigation system was
activated and tested using
the moon and Jupiter as targets.

The spacecraft's high gain antenna, which will relay images and data of
the cometary collision, was
activated and is operating properly. A trajectory correction maneuver
was performed, refining the
spacecraft's flight path to comet Tempel 1. The maneuver was so
successful that a second one planned
for March 31 was cancelled.

Another event during commissioning phase was the bake-out heating of the
spacecraft's High
Resolution Instrument (HRI) to remove normal residual moisture from its
barrel. The moisture was a
result of absorption into the structure of the instrument during the
vehicle's last hours on the
launch pad and its transit through the atmosphere to space.

At completion of the bake-out procedure, test images were taken through
the HRI. These images
indicate the telescope has not reached perfect focus. A special team has
been formed to investigate
the performance and to evaluate activities to bring the telescope the
rest of the way to focus.
Future calibration tests will provide additional information about the
instruments' performance.

The Deep Impact spacecraft has four data collectors to observe the
effects of the collision: a
camera and infrared spectrometer comprise the High Resolution
Instrument; a Medium Resolution
Instrument (MRI); and a duplicate camera on the Impactor Targeting
Sensor (ITS). They will record
the vehicle's final moments before it is run over by comet Tempel 1 at
approximately 23,000 mph. The
MRI and ITS are performing as expected.

"This in no way will affect our ability to impact the comet on July 4,"
said Rick Grammier, Deep
Impact project manager at NASA's Jet Propulsion Laboratory (JPL),
Pasadena, Calif. "Everyone on the
science and engineering teams is getting very excited and looking
forward to the encounter."

Dr. Michael A'Hearn of the University of Maryland, College Park, Md.,
added, "We are very early in
the process of examining the data from all the instruments. It appears
our infrared spectrometer is
performing spectacularly, and even if the spatial resolution of the High
Resolution Instrument
remains at present levels, we still expect to obtain the best, most
detailed pictures of a comet
ever taken."

Deep Impact is comprised of two parts, a flyby spacecraft and a smaller
impactor. The impactor will
be released into the comet's path for the planned high-speed collision.
The crater produced by the
impactor is expected to range from the width of a house up to the size
of a football stadium and be
from two to 14 stories deep. Ice and dust debris will be ejected from
the crater revealing the
material beneath.

Along with the imagers aboard the spacecraft, NASA's Hubble, Spitzer and
Chandra space telescopes,
along with the largest telescopes on Earth, will observe the effects of
the material flying from the
comet's newly formed crater.

An intimate glimpse beneath the surface of a comet, where material and
debris from the formation of
the solar system remain relatively unchanged, will answer basic
questions about the formation of the
solar system. The effects of the collision will offer a better look at
the nature and composition of
these celestial travelers.

The University of Maryland provides overall mission management for this
Discovery class program.
Project management is handled by JPL. The spacecraft was built for NASA
by Ball Aerospace &
Technologies Corporation, Boulder, Colo.

For more information about Deep Impact on the Internet, visit:

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Received on Thu 31 Mar 2005 07:58:03 AM PST