[meteorite-list] NASA Uses CT Scan To Probe Meteorite

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:07:01 2004
Message-ID: <200210171619.JAA22175_at_zagami.jpl.nasa.gov>

http://www.floridatoday.com/news/space/stories/2002b/101702meteorite.htm

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 Nondestructive
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 millimeter 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 Maneuvering 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.
Received on Thu 17 Oct 2002 12:19:53 PM PDT