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CX2SA > ISS 05.10.05 03:43l 131 Lines 6134 Bytes #999 (0) @ WW
BID : 42784_CX2SA
Read: DJ7KA GUEST OE7FMI
Subj: CRITICAL RESEARCH ON THE ISS
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Sent: 051005/0225Z @:CX2SA.LAV.URY.SA #:42784 [Minas] FBB7.00e $:42784_CX2SA
From: CX2SA@CX2SA.LAV.URY.SA
To : ISS@WW
[sarex] CRITICAL RESEARCH ON THE ISS
SUBMITTED BY ARTHUR N1ORC - AMSAT A/C #31468
Photographing Physics: Critical Research in Space
http://www.nasa.gov/mission_pages/station/science/BCAT_feature_093005.html
(TO SEE PICTURES)
10.03.05
On a quiet March afternoon in Cleveland, Ohio, Bill Meyer browsed the second
floor of a Department Store. He was just about to buy a pair of shoes at 70
percent off when his cell phone rang.
Sighing, he lifted the phone to his ear and said, "Hello?"
"Is this William Meyer?" the voice on the other end inquired.
"Yes, it is," he replied.
"This is CapCom at the Johnson Space Center," the voice said. "Can you get to a
land line? You have a phone call from the International Space Station."
Astronaut Leroy Chiao examines BCAT-3 samples on space station The normally
mild-mannered scientist rushed to the customer-service counter. Astronaut
Leroy Chiao had a question about an important space station experiment, and he
could only take the call from a land line.
Store employees were more than happy to help. "They were so excited that they
were jumping up and down," said Meyer, who works at NASA's Glenn Research
Center. "I wouldn't be surprised if their heads knocked out some of the ceiling
tiles."
Just before he called, Chiao had been photographing the Binary Colloidal Alloy
Test-3 (BCAT-3). This book-sized container holds ten sample cells filled with
colloids, or tiny particles suspended in fluid. A hundred times smaller than a
fine human hair, colloids are everywhere. Milk, paint, makeup and smoke are
just a few examples.
On Earth, the BCAT-3 colloids aren't very surprising -- they just sink to the
bottom of the container. But in the absence of gravity, they behave like slow
atoms, allowing scientists to model all sorts of atomic behavior.
According to the BCAT-3 scientists, studying colloids in space could lead to
revolutionary advances in technology, such as computers that operate on light,
new pharmaceuticals, clean power sources and unique propellants for rocket
engines.
BCAT-3 focuses on two frontiers of science: critical points and
crystallization.
Critical Point Research
In a pot of boiling water, bubbles of vapor begin to form at the bottom of the
pot and grow until they escape into the atmosphere. The water exists
simultaneously in two states -- liquid and gas. If you could increase the
temperature and pressure much higher than the average stove and pot allow, the
water would reach its critical point, where the liquid and vapor cannot be
distinguished.
Critical point samples in space - the colloids appear blue and the solvent
appears nearly black. Just above that is the supercritical region, where the
liquid and gas are no longer distinct states, but rather form a homogeneous
supercritical fluid. Like gases, supercritical fluids flow easily, but they
also can transport dissolved materials and thermal energy, like liquids do.
Photos of two of the BCAT-3 critical point samples on the International Space
Station show the colloids (blue) and solvent (dark) separating after seven days
(left) and eleven days (right). The colloids represent liquid, and the solvent
represents gas. Credit: NASA (See all six samples.)
Supercritical carbon dioxide is used to extract molecules from plants for
pharmaceuticals. Supercritical water is used to remove toxic waste from
contaminated soil. And some scientists believe supercritical fluids could be
used to extract magnesium from rocks on Mars to make rocket fuel.
Six of the BCAT-3 experiment samples were created by David Weitz and Peter Lu
at Harvard University to study atomic behavior near the critical point.
Crystallization Research
Scientists also study colloids because they are the right size to manipulate
light. Over time, they form crystals that can split up light and send it in
different directions.
By enhancing our ability to control light, scientists hope to improve fiber
-optic communication systems and build computers that operate on light instead
of electricity. Because cosmic rays degrade electronic circuits in space, these
technologies are essential to fulfilling the Vision for Space Exploration with
journeys to the moon, Mars and beyond.
The optical properties of a crystal vary depending on its size and shape. So
scientists Peter Pusey and Andrew Schofield at the University of Edinburgh are
studying BCAT-3 samples to see how changing the size and proportion of colloids
affects the crystals. Meanwhile, University of Pennsylvania researchers Arjun
Yodh and Jian Zhang are trying to determine how crystals form on the surface of
a container in microgravity.
Catching Colloids in Action
Since the BCAT-3 scientists can't join their experiments on the International
Space Station, they depend on the station crew to photograph the samples and
collect data for them.
Hoffman, Lu and Foale examining BCAT-3 training samples at JohnsonImage . NASA
Glenn project manager Monica Hoffman and Harvard grad student Peter Lu train
Astronaut Michael Foale to photograph BCAT-3 samples at the Johnson Space
Center before he takes off on Expedition 8. A flashlight positioned at a high
angle behind the experiment illuminates the samples.
Because colloids behave differently in space than they do on Earth, the
researchers are seeing some surprising results -- so surprising that NASA has
agreed to keep the project on the space station for another year. In October,
Expedition 12 Commander William McArthur will pick up the project where Chiao
left it.
If only Meyer can get McArthur to call him while he's shopping. The employees
at the store were so happy to hear from Chiao that when Meyer checked out they
gave him a scratch-off coupon -- another 10 percent off that pair of shoes.
----
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