MSL-1 Public Affairs Status Report #5
6 a.m. CDT, April 7, 1997
MET 02/16:39
Spacelab Mission Operations Control
Marshall Space Flight Center
  Spacelab crew members and science teams at Marshall Space Flight
Center in Huntsville, Ala., worked steadily through the night to
complete as much science as possible in the remaining hours of the
mission. Due to a malfunction in the Space Shuttle's number two
fuel cell, Columbia is now scheduled for landing Tuesday afternoon.
  The abbreviated mission came as a disappointment to participating
scientists.  The atmosphere, however, was also marked by bright spots,
such as the excitement of one science team which recorded a
"first" in combustion research.  Payload Commander Dr. Janice
Voss completed several runs of the Droplet Combustion Experiment last
night. "Six burns were successful and for the first time, we're
burning free droplets" said Principal Investigator Dr. Forman
Williams of the University of California at San Diego.
  The experiment is collecting information on burning rates of flames,
flame structures and conditions under which flames are
extinguished. "We can't get this kind of information from
ground-based experiments" said Williams. "We have burned at two
different atmospheres of oxygen concentration and calculated the
burning times of free fuel droplets at each."
  Combustion of fuel droplets is an important element in heating
furnaces for materials processing, heating homes and businesses, and
producing energy in gas turbines and gasoline-powered
engines. Findings from this investigation are providing researchers
with a better understanding of the combustion process and may lead to
cleaner and safer ways to burn fossil fuels as well as more efficient
methods of generating heat and power on Earth.
  The Coarsening in Solid-Liquid Mixtures experiment continued to run
in the Middeck Glovebox facility. This investigation, led by Dr. Peter
Voorhees of Northwestern University in Evanston, Ill., is studying
coarsening in metal mixtures at very high temperatures. During
coarsening, small particles shrink by losing atoms to larger
particles, resulting in a lack of uniform particle distribution. This
weakens the material and shortens its life-span.
  "Because of our small size and power usage we've been able to
continue experiment runs, completing four runs with good
success" said John Caruso, project manager for the
experiment, with NASA's Lewis Research Center. "From the
engineering data we've received, we expect to get
satisfactory science. We expect the samples will show uniform
particle distribution."
  Findings from this research may lead to improved manufacturing
processes and stronger, longer-lasting materials.
  Early Sunday evening, Payload Specialist Dr. Roger Crouch began a
study of the Structure of Flame Balls at Low Lewis- number, called
SOFBALL, in the Combustion Module. The study is designed to determine
under what conditions a stable flame ball can exist and if heat loss
is responsible in some way for the stabilization of the flame ball
during burning.
  "The two completed runs were successful beyond my wildest dreams"
said Principal Investigator Dr. Paul Ronney of the University of
Southern California in Los Angeles. During the first experiment, a
mixture of hydrogen, oxygen and carbon- dioxide burned in the facility
for the entire 500-second limit. This result is significant because,
"these are the weakest flames ever burned -- lowest temperature,
weakest, most diluted mixtures" explained Ronney. "These
mixtures will not burn in Earth's gravity."
  "We have known that burning weaker mixtures increases efficiency"
said Ronney, "but not much is known about the burning limits of these
mixtures." Findings from this experiment will also provide researchers
with a better understanding of the combustion process and will help to
improve theoretical models. "Combustion models give different results
for these types of flames" said Ronney.  "This is an acid test to show
which, if any, current combustion modules should be used."
  The Experiment Control Systems Computer, which relays ground-
commands to the experiment facilities, malfunctioned. The Spacelab
crew performed a procedure to disconnect the computer from the master
timing unit, allowing the computer and experiments to go to internal
timing sources.
  In the electromagnetic containerless processing facility, called
TEMPUS, two experiment runs ended early when the undercooled,
levitated samples came in contact with the wall.  Undercooling refers
to a liquid being cooled to a temperature below its normal freezing
point yet remaining in a liquid state -- like cooling a glass of
distilled water on Earth.  However, if the glass is tapped or
disturbed, ice begins to form quickly -- just as the samples began to
solidify when they hit the wall. Another study of undercooled
materials was initiated in the facility. This experiment, which
measures the specific heat of undercooled metallic melts, is examining
how metallic glass forms in zirconium-based alloys.
  Before ending his shift early this morning, Crouch began another run
of the Liquid Phase Sintering experiment in the Large Isothermal
Furnace. This experiment is investigating how liquid metals form a
mixture without reaching the melting point of the formed metallic
alloy. Information gathered will provide researchers with a better
understanding of liquid phase sintering in low-gravity and comparisons
of findings to theoretical predictions, should improve theoretical
models.  The principal investigator for the study is Dr. Randall
German of Pennsylvania State University in University Park, Pa.
  Dr. Donald Thomas and Dr. Gregory Linteris resumed science
operations aboard the Shuttle early this morning. Thomas completed
another run of the Liquid Phase Sintering experiment in the Large
Isothermal Furnace before beginning to deactivate protein crystal
growth experiments.
  After completion of another run of the Droplet Combustion
Experiment, Linteris began reconfiguring the Droplet Combustion
Apparatus for return to Earth.
  Ahead, crew members will continue to deactivate experiment
facilities in preparation for the Shuttle's journey home.
  The next scheduled Public Affairs Status report will be
issued at approximately 6 p.m., April 7.
For more information call Spacelab Newscenter at Marshall Space Flight
Center at (205) 544-6535 or visit our web sites. For Spacelab payload
information: http://liftoff.msfc.nasa.gov/spacelab/msl/main.html and
for microgravity science information:
http://www.ssl.msfc.nasa.gov/msl1/ msl1hframe.htm