Mundrabilla
Meteorite
18th
October 2002
There
has been quite a bit of talk about the Australian Mundrabilla
meteorite recently. NASA has used a special scanning machine to
look inside the meteorite and got a bit of press. This
story appeared
in Florida Today and here is a Media
Release from
NASA which appeared on the list. I also visited Adelaide earlier
in the year and saw the 2.5 tonne 'half stone' of the second
largest Mundrabilla mass found. I posted a story
about this
experience on the list also. After I posted my story, Bernd
Pauli was kind enough to send me a scan of a unusual post card
someone sent him many years ago. The photo is below my story.
Mundrabilla
in Adelaide
Thought
I would share a story about Mundrabilla. I was in Adelaide
earlier in the year and they actually have a 2500 kg piece of
the second largest mass at the Museum. (Half the 5 or 6 tonne
mass. Can't remember the exact weight.) It is located right at
the front entrance. I have not seen a good
photo of one of the two large masses on the internet, but
'in-person' it is a truly remarkable specimen. All those times
you have read that phrase "Meteorites NEVER have holes in
the surface" is completely turned upside-down. There
is not one flat section of the Mundrabilla crust. It is unique
in the sense that when Mundrabilla weathered, the troilite
disappeared and left big holes and pockets in the surface. Some
of these went very deep and curved their way right down out of
sight. Others were easily big enough to fit a hand in. A truly
amazing piece of natural history!!!
"A local gets to know the newest ET in town!"
NASA
Researchers Probe Meteorite
A
new NASA study of a one-of-a-kind meteorite found 36 years ago
in Australia could help provide the science community and
industry with fundamental knowledge for use in the design of
advanced materials. Such materials could be used for future
spacecraft, improved jet aircraft and in various manufactured
goods from cars to household materials. In addition, the
meteorite - now at Kennedy Space Center - could help reveal
secrets about the core of our planet and its magnetic field. The
100-pound Mundrabilla meteorite sample, which is on loan to
Marshall Space Flight Center from the Smithsonian Institution's
National Museum of Natural History, is being studied by MSFC and
KSC, primarily through the use of KSC's Computed Tomography
Scanner. Dr. Donald Gillies, discipline scientist for materials
science at MSFC's Microgravity Science and Applications
Department, is the Principal Investigator on the study.
"Most meteorites are solid chunks of metal, surrounded by a
rocky surface. This one is a combination of materials
(iron-nickel and iron-sulfide) that became solid at different
rates in cooling over millions of years," Dr. Gillies said.
"It offers an amazing opportunity for understanding
fundamentals of alloy formation." Pete Engel, an
engineering specialist in Wyle Laboratory's Non-destructive
Testing Laboratory at KSC, has processed the scans of the
meteorite at KSC. "The CT Scanner is able to reveal the
untouched internal structure of the meteorite by detecting
differences in the densities of its materials," Engel said.
"Without a tool like the scanner, it would be impossible to
study the inside of the meteorite without altering it by sawing
into it or grinding it up." The idea behind computed
tomography - first used in the medical field - is to create a
picture of a very thin cross section of an object by passing a
very thin fan of X-rays or gamma rays through it and then
repeating the process until every slice of an object is imaged
in order to create a 3-D image. Dr. Gillies and Engel are
conducting the meteorite CT work at KSC using gamma rays given
off by a pencil lead-sized piece of radioactive cobalt as it
decays. "This meteorite, like all meteorites, was formed in
a lower gravity environment than here on Earth," Dr.
Gillies pointed out. "Like experiments performed on the
Space Shuttle or the International Space Station, this research
allows us to look at fundamental science questions. Unlike our
own flight experiments, this one represents a billion year
solidification experiment in low gravity."
NASA
uses CT scan to probe meteorite
By
Kelly Young FLORIDA TODAY
October
17, 2002
CAPE
CANAVERAL -- Engineers at Kennedy Space Center have peered into
the heart of a 100-pound meteorite without cutting it open,
using the same technology as a medical CT scan. But the space
center's Computed Tomography Scanner is hundreds of times more
sensitive than medical scans. Behind a 7,000-pound,
steel-encased lead door inside the Non-destructive Testing
Laboratory, engineers use a tiny piece of radioactive cobalt-60
to shoot gamma rays or X-rays through a meteorite chunk, which
stands like a two-foot-tall pillar and slides along a track in
between the radiation source and the sensors. Meteorites are
chunks of rocks that survived a fiery entry through Earth's
atmosphere and landed on the planet. The Smithsonian Institution
loaned Marshall Space Flight Center the meteorite piece, which
is actually part of a 6-ton meteorite that was discovered in
Mundrabilla, Australia. NASA probably will return the meteorite,
which could be worth up to $1 million, within the next week.
"The Smithsonian's anxious to get it back," said Pete
Engel, an engineering specialist with Wyle Laboratories, which
operates the computer tomography machine for NASA. It took one
week to get 500 scans of one millimetre each that covered most
of the meteorite. Think of them as floor plans of a 500-story
skyscraper. Inside, scientists are examining crystals of iron-sulfide
and iron-nickel. There are also a few pockets of gas inside the
meteorite. The crystals formed after the hot meteor landed and
later cooled. It may take six months to a year for scientists to
analyze the results. NASA regularly grows crystals on the
International Space Station because they form more purely in
microgravity than they do on Earth. They want to study this
meteorite because the crystals formed naturally during a long
exposure to space. Crystals also have industrial purposes.
Crystals of mercury, cadmium and tellurium are used inside
infrared cameras, Engel said. The $1 million scanning machine
has been at the space center since 1985. In its time there, it
has been a safety measure for the shuttle program. It scanned
dents on an Orbital Manoeuvring System engine that helps the
shuttle shift from one orbit to another. They have scanned wear
and tear on the shuttle's landing gear and on the insulating
tiles on the orbiter's outside. It can spot things on the inside
that otherwise would not be possible without taking the entire
device apart.
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