Dr. Michael Foale will begin testing an experiment developed by
Dr. John A. Pojman, a professor in the Department of Chemistry and
Biochemistry, aboard the international space station on Jan. 20.
Fluid in Microgravity (MFMG) experiment will test how miscible fluids
- those that completely dissolve in each other - interact without
the interference of gravity. The test, conducted with unused urine
collection syringes and Zip-lock bags, can be performed only in
weightlessness. However, it does have some down-to-earth implications,
used to simulate the experiment provide information on the fundamental
interactions between molecules," he said.
fluids, like oil and water, exhibit something called "interfacial
tension" because of the different ways that each type of molecule
pulls on each other. "This interfacial (surface) tension is
what allows a water skeeter to walk on water," Pojman explained.
The experiment, accepted by NASA in April, will test a time-worn
but unsupported theory. "One hundred years ago, a scientist
named Korteweg predicted that miscible fluids could act like immiscible
fluids until they had diffused and become uniform," Pojman
there has been much theory and some provocative experiments during
the intervening century, no definitive experiments have been performed.
This simple experiment will be a step toward a complete test of
If a stream
of one immiscible fluid is injected into another in weightlessness,
the stream will break into drops - a phenomenon called the Rayleigh-Tomotika
instability. By injecting honey into water and observing if the
honey stream breaks into drops, Foale will test to see if the same
breakup occurs with two miscible fluids, Pojman said.
the honey is denser than water," he said, "the stream
sinks in the water when we try to do the experiment on earth."
"A drop of immiscible fluid in another fluid will always become
spherical in weightlessness. We will test if an irregular drop of
water injected into honey does the same. To prevent the drop from
floating to the top of the honey, the experiment must be performed
will also be performed while heating the fluids to test if miscible
fluids migrate - something that is seen with immiscible drops and
a veteran of more than 800 flights aboard NASA's KC-135 research
aircraft, also known as the "Vomit Comet." He has also
traveled to NASA's Marshall Space Flight Center several times to
develop the actual crew procedures for the test.
On Dec. 29,
Russian cosmonaut Alexander Kaleri heated a can of Russian honey
to make sure it would not be crystallized when Foale begins performing
the experiment on Jan. 20. On that day, Professor Pojman will be
present at the NASA MSFC control room to discuss the experiment
with Foale, who will then perform the heating experiments over the
next four days. "This is tremendously exciting," Pojman
said. "My students, collaborators and I have been working on
this research since 1998, and we are eager to see how our fluids
be in Lyon, France until Jan. 18 working with Dr. Vitaly Volpert
and Dr. Nick Bessonov, of the Université Lyon I, who have
performed the computer simulations for the MFMG experiment. Pojman
is also an invited speaker at a workshop on diffuse interfaces during
his visit. He just returned from a conference in Reno, Nev., where
he also talked about his work.
The other set
of experiments have yet to be scheduled.