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.