IML-2 Public Affairs Status Report #05  
6:00 p.m. CDT, July 10, 1994 
2/6:17 MET 
Spacelab Mission Operations Control 
Marshall Space Flight Center 
      
    The experiment-packed second International Microgravity Laboratory mission
is staying "remarkably near schedule" after two days in orbit, according to
Mission Manager Lanny Upton. Crew members and ground controllers worked
together to complete a variety of experiments and resolve some of the
challenges associated with keeping a complex science payload up and running.

    Payload Commander Rick Hieb successfully adjusted a communications cable
this morning to establish data downlink from the Japanese life sciences
equipment.  The repair allowed the Japanese team to receive information from
their Real-Time Radiation Monitoring Device for the first time in the flight.
The device actively measures the high-energy cosmic radiation which enters the
Spacelab in orbit, then transmits those measurements to the ground.  Signals
also are being transmitted to remote centers for comparison with current
radiation information, such as optical and X-ray observations.  The IML-2
device is a first step toward creation of a space weather-forecasting network
which eventually could warn astronauts on long flights to take shelter from
radiation storms.

        Payload Specialist Chiaki Mukai reported that the medaka fish in the
Animal Aquatic Experiment Unit are more active than they had been the first day
of the mission, but they still seem disoriented in microgravity.  She counted
10 medaka eggs in the aquarium and gave the fish their first scheduled feeding.

Mukai made the first videotapes of fruit flies in Dr. Roberto Marco's study of
microgravity's effect on the aging process.  Scientists have observed that
flies age more quickly in space than on Earth. This experiment tests a theory
that premature aging is linked to increased activity as the flies attempt to
move in microgravity, along with excessive respiration.

   Mission Specialist Don Thomas completed an experiment in the Slow Rotating
Microscope Centrifuge, or NIZEMI, facility that studies how a green algae
called chara responds to varying levels of gravity. "We knew from sounding
rocket flights that gravity-sensing crystals in the plants would move from
their normal position, but we didn't know how long they would keep moving or
how far they would go.  One surprise was that the movement stopped at a certain
place, suggesting there must be something which dictates how far the crystals
can move," said Co-investigator Dr. Brigitte Buchen, of the University of Bonn,
Germany. "I admire the speed and certainty with which crew members have
selected the best cells for study under the NIZEMI microscopes," she added.

    The next two NIZEMI experiments searched for gravity thresholds of a simple
plant organism called Euglena gracilis and a unicellular organism called
Loxodes straitus.  Knowing how simple organisms respond to gravity can help
scientists interpret behavioral responses in more complex organisms and even
humans.

   Early this morning, scientists used the Electromagnetic Containerless
Processing Facility (or TEMPUS, for its German name) to study an oscillating
sphere of melted gold. "We got some very interesting measurements of viscosity
and surface tension above the melting point," said Dr. Georg Lohoefer, a
colleague of Principal Investigator Dr. Ivan Egry. Scientists can deduce the
viscosity, or internal friction, of the liquid by the rate at which the drop
returned to a spherical shape after being disturbed.  Surface tension, the
force that keeps a liquid together in a drop, can be determined by the
frequency at which the sample oscillated before it stabilized to a sphere.  A
better understanding of the properties of liquid metals is of interest to
electronics and manufacturing industries as well as to theoretical scientists.

The TEMPUS team decided not to melt their next sample, a nickel/tin alloy, when
video views from the top of the experiment chamber revealed that the metal
sphere was not centered in the sample cage.

    TEMPUS is the first electromagnetic containerless processing facility to
fly in space for more than a few minutes.  As is often the case with any
complex, new space hardware, the team is fine-tuning methods for controlling
their equipment during its initial days of operation in orbit. "We expected we
would have to complete calibration of this facility during the mission, since
there is no way to do it in gravity on Earth," said IML-2 Program Scientist Dr.
Brad Carpenter. After recalibration, another experiment which uses a gold and
copper alloy to study viscosity and surface tension went on as planned.

    The mission's first Critical Point Facility experiment drew to a close this
afternoon after 43 hours of operation.  Designed by Dr. Hermann Klein of the
German Space Agency, the investigation aims to determine how long it takes a
fluid to stabilize, or reach equilibrium, after it has been disturbed.  Klein
studied these density equilibration time scales in normal fluids aboard German
Spacelabs D-1 and D-2. On this mission, he is making similar observations in a
fluid near its critical point, where it behaves like a liquid and a gas at the
same time.  At that point, a small interference may cause large changes.
According to Co-investigator Dr. Rainer Nhle, it appears stabilization took
longer than had been expected.  If this holds true after post-flight analysis,
it could affect the way future investigations are designed.  Nhle said IML-2
controllers gave his team more than double the real-time video they had
expected, greatly increasing the scientific outcome.

  Hieb spent part of the afternoon as the subject of a Lower Body Negative
Pressure Experiment. His lower body was encased in a fabric bag, sealed at the
waist, in which a partial vacuum can be created.  Mukai monitored his blood
pressure and heart rate as pressure within the bag was slightly lowered, then
raised again.  This so-called negative pressure pulls fluids back into the
legs.  Mukai is now taking her turn as test subject .  The tests will be
repeated on both crew members three more times during the mission to monitor
their adaptation to space flight.