IML-2 Status Report #15
 
IML-2 Public Affairs Status Report #15
6:00 p.m. CDT, July 15, 1994
7/6:17 MET
Spacelab Mission Operations Control
Marshall Space Flight Center
 
    The mid-point of the second International Microgravity Laboratory mission
was a day of both accomplishments and challenges for the crew, experiment
scientists and the payload control team.
 
    Payload Commander Rick Hieb made three attempts to flush a suspected air
bubble from the Free-Flow Electrophoresis Unit's water cooling loop.  However,
the system still is not maintaining proper temperature control.  Mission
managers and the Japanese Space Agency's life science team put activities with
the electrophoresis unit on hold while they consider additional alternate
methods for potentially solving the problem.
 
    One of Hieb's first assignments this morning was to preserve samples for a
Biorack cell aggregation experiment provided by Dr. Uwe Heinlein of Heinrich-
Hein University in Germany. Early in the mission, sample containers of primary,
or unattached, cells from two types of mouse tissue were placed in the Biorack
incubator.  Heinlein will analyze the preserved samples to see whether the
primary cells were able to reassemble into organized tissues.  This cannot be
done on Earth, because gravity causes the cells to attach to the bottom of the
culture flask before they can aggregate.  If the cells did aggregate in space,
results could help scientists understand how cells recognize and interact with
one another to build up into tissues.  This insight could be applied to
correcting problems related to tissue formation.
 
    In its first experiment run this morning, the TEMPUS electromagnetic
containerless processing facility levitated and melted a zirconium-nickel
sphere, then "squeezed" the metal sample, causing it to oscillate.  Dr. Julian
Szekely and his team from MIT will analyze the frequency of the oscillations
and how long it took the oscillations to relax in order to determine the
material's surface tension and viscosity. "We can see from the downlink data
that we will get good measurements of both properties in the normal liquid and
undercooled liquid states," said Elliot Schwartz, a member of Szekely's team.
They succeeded in bringing the liquid sample down to about 70 degrees
Fahrenheit (40 degrees Celsius) below its normal solidification temperature.
This particular zirconium-nickel sample was chosen for today's experiment
because it had performed extremely well in a heat-capacity investigation last
night.
 
    The European Space Agency's Bubble, Drop and Particle Unit, on its first
space flight, is functioning well.  Dr. Dieter Langbein of ZARM Institute in
Bremen, Germany, was pleased to get an extended run early this morning of his
experiment to study the behavior of liquids in containers.  The experiment was
listed on the pre-mission schedule as a spare, to be performed only if time
became available.  The facility team sent commands to partially fill four
prism- shaped containers with a liquid, then incrementally raised and lowered
temperatures, to study how different volumes and temperatures affected liquid
shapes and the way they contacted the containers.  A better understanding of
this behavior will be valuable for space-based materials science experiments
and for designing better surface-tension tanks to dispense fuel in
weightlessness.
 
    The next Bubble, Drop and Particle unit experiment was designed to study
how voids in solid metals form air bubbles when the materials are melted in
space.  It was terminated when a liquid in the outer portion of the experiment
container degraded the quality of digital video images being sent to the
ground.
 
    Principal investigators for NIZEMI slow-rotating centrifuge microscope
experiments continued their methodical observations of plants at varying levels
of gravity.  This morning's activities focused on the single-cell plant,
Euglena. The plants have been studied extensively on Earth, but this is the
first Shuttle experiment to examine them.  Principal Investigator Dr. Donat
Hader hopes to determine whether their process for perceiving gravity is active
or passive.  This afternoon, Dr. Dieter Volkmann examined the roots of more
complex plants, cress seedlings, to monitor how they adapt to different gravity
environments.
 
    Payload Specialist Chiaki Mukai reported that the Medaka and newts in the
Animal Aquatic Experiment Unit were doing well, and she and Hieb took
ultrasound images of their own bodies for the Spinal Changes in Microgravity
experiment.  A Critical Point Facility study of heat transfer in fluids near
their critical point continued throughout the day.
 
    Tonight's experiment activities will focus on biological processing
experiments with the French Space Agency's RAMSES, the mission's other
electrophoresis separation facility.  Investigations will continue for the
majority of the other IML-2 experiment groups.
 
NASA issues four status reports daily on STS-65/IML-2 activities: science
operations reports from Spacelab Mission Operations Control in Huntsville at
approximately 6 a.m. and 6 p.m., and orbiter operations reports from Mission
Control in Houston at approximately 8 a.m. and 5 p.m.