STS-75 Day 13 Highlights

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On Tuesday, March 5, 1996, 8 a.m. CST, STS-75 MCC Status Report # 23 reports:

Aboard Columbia, crew members continue to work around the clock investigating flame behavior in a controlled, microgravity environment. Early today, a balky cooling system froze up again but was cleared using the same procedure run a couple of days ago.

The flash evaporator system core flush procedure was identical to the one carried out on Saturday to melt ice and recover use of the subsystem which is designed as a subtle method for dumping excess water overboard without disrupting the experiments on board. The FE also cools the freon used to keep orbiter and payload electronics at operating temperatures.

The unit was turned on to evaluate its operation with freon running at a slightly higher temperature than usual to prevent ice formation in the core. The test was conducted on one of two controllers for the unit. A second test on the alternate controller may be conducted later.

Columbia is scheduled to pass within 50 to 60 miles of the tethered satellite at 10:25 this morning, just as the satellite enters orbital sunrise. It is unclear whether the crew will be able to view the satellite as it did several days ago.

This morning, the astronauts took time out from science operations to discuss the progress of the mission with reporters in the United States and Europe.

With an extra day on orbit for science operations, the seven astronauts will continue work supporting the United States Microgravity Payload experiments. The end of Columbia's 19th mission is now scheduled for 6:19 a.m. central on Friday.

Despite the intermittent freeze-up of the FES, the orbiter continues to provide a stable environment for USMP operations. Columbia is in an orbit 181 by 173 statute miles.

On Tuesday, March 5, 1996, 6 a.m. CST, STS-75 Payload Status Report # 18 reports: (11/15:42 MET)

Along with yesterday's decision to extend the third United States Microgravity Laboratory (USMP-3) mission by one day to enhance science return, the space science network also expanded with an historic first for microgravity science. "This is the first time a principal investigator has commanded a microgravity science instrument on the Space Shuttle from his home institution -- a U.S. college campus," USMP-3 Program Scientist Dr. Steve Davison reported, referring to the remote commanding of the Isothermal Dendritic Growth Experiment (IDGE).

Dr. Martin Glicksman, of the Rensselaer Polytechnic Institute (RPI) in Troy, N.Y., has the distinction of being that principal investigator. Around 9:10 a.m. CST, one of Dr. Glicksman's team members, who joined him from the NASA Lewis Research Center, sent a command to their experiment in Columbia's cargo bay. That step began a third science phase for the dendrites research team, to continue studying how metal alloys solidify free from the convective flows caused by Earth's gravity.

Throughout the mission, the Rensselaer Operations Control Center crew has been working hand-in-hand with their counterparts at the NASA Marshall Space Flight Center's Spacelab Mission Operations Control to analyze data produced by the IDGE experiment. Now, with RPI in the driver's seat, the results of their first growth cycle became clear, as the first dendrite of this operational phase emerged in record time. The characteristics of these microscopic crystals help determine the strength and flexibility of products such as automobile engine blocks and jet engine turbine blades. The ultimate goal of the IDGE investigation is to improve ground-based materials processing for metals ranging from aluminum to steel.

Another collaborative effort between NASA centers is the Advanced Automated Directional Solidification Furnace (AADSF) investigation. AADSF brings together a sophisticated Marshall- developed furnace for growing semiconductor materials and a science team under the direction of Principal Investigator Dr. Archie Fripp of NASA's Langley Research Center.

The three delicate lead-tin-telluride crystals that have been successfully grown by AADSF during this mission are slated for microscopic study when the samples are returned to Earth. Referring to the detailed science support provided by the Spacelab Mission Operations Control cadre, Dr. Fripp commented that his experiment performed "flawlessly." "The pilot and crew put the Shuttle in the proper attitudes required for sample processing and held them there," Fripp said. Monday afternoon, the high- temperature AADSF furnace was cooled and prepared for landing on Friday.

The Critical Fluid Light Scattering Experiment, known as ZENO, also shows the value of cooperation between NASA, academia and industry. Under the direction of Dr. Robert Gammon of the University of Maryland in College Park, the ZENO team includes members of NASA's Lewis Research Center and Ball Aerospace. As his research team moves to within millionths of a degree of the point where the xenon sample will exist simultaneously as a liquid and a gas, known as the critical point, Dr. Gammon also complimented the work of the Spacelab Mission Operations Control cadre. This special operations team works with the orbiter crew to put the Shuttle in the best possible position for the USMP-3 microgravity experiments. The basic science questions that the Zeno investigation seeks to answer could improve chemical engineering processes ranging from applying special paints to handling toxic waste.

The MEPHISTO investigation brings together nations working toward a common goal, with their French Space Agency center in Toulouse, France, and their NASA teams at the Marshall Center and the University of Alabama in Huntsville all gathering data about crystal solidification. "Most of the materials we use are formed by solidification," explained MEPHISTO principal investigator Dr. Jean-Jacques Favier. "This is true for semiconductors as well as high-strength alloys." The Information Age has linked people from around the world, and research conducted by the international MEPHISTO team could lead to faster computers and more versatile metals.

In the next 24 hours, combustion experiments in the Middeck Glovebox will continue gathering more science than originally planned, as crew members burn additional samples for the Radiative Ignition and Transition to Spread Investigation. The Marshall- managed Glovebox experiments are contributed by NASA's Lewis Research Center and the National Institute for Standards and Testing. Meanwhile, the MEPHISTO team plans to speed up one of their furnace's solidification cycles to coincide with a Shuttle thruster firing to monitor its effect on their sample.

On Tuesday, March 5, 1996, 4 p.m. CST, STS-75 MCC Status Report # 24 reports:

Columbia's astronauts had one last look at the Tethered Satellite late this morning telling flight controllers they could see both the satellite and the tether hanging beneath it.

Lighting precluded a viewing opportunity during the point of closest approach between the two spacecraft, but one orbit later the crew saw and filmed TSS from a distance of about 450 nautical miles. The videotape was played back for flight controllers on the ground this afternoon. Today's pass of the satellite marks the final viewing opportunity for the seven astronauts on board Columbia.

Shortly before 7 p.m. central today, Franklin Chang-Diaz, Jeff Hoffman and Claude Nicollier will participate in the final on-orbit interview for the flight. The three crew members will discuss their missions with both Univision and Telenoticias, the two largest Hispanic television networks.

Wednesday morning, Commander Andy Allen will attempt to make contact with the crew of Atlantis on Launch Pad 39-B. STS-76 Commander Kevin Chilton and the crew of the next Shuttle/Mir mission will be on board Atlantis participating in a final dress rehearsal of their planned March 21 launch.

Columbia continues to provide a stable platform for the continuing scientific investigations being conducted in the United States Microgravity Payload.

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