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Saturday, November 22, 1997, 7:00 a.m. CST
11.22.97
 
STATUS REPORT : STS-87-03s
 
 
STS-87 Mission Science Report # 3s
 
 

Friday was a day of “spectacular” science for the Fourth United States Microgravity Payload aboard the Space Shuttle Columbia, as the calibration of one experiment produced the most precise measurement of temperature ever recorded in space, and another experiment produced some surprising results.

During calibration of an experiment to help better understand how making electronic parts smaller ultimately affects their performance, scientists achieved a temperature measurement to a precision of about one-tenth-of-a-billionth of a degree kelvin.

The experiment’s principal investigator, Dr. John Lipa of Stanford University in Stanford, Calif., attempted to put that measurement into understandable perspective. “The temperature resolution of one-tenth-of-one-billion of 1 degree is equivalent to the ability to measure the distance between Los Angeles and New York to the thickness of a fingernail.”

Dr. Peter Curreri, mission scientist for the Fourth U.S. Microgravity Payload, called the measurement “spectacular,” and said the achievement “has importance for fundamental physics. The information we learn from the experiment can be applied to future generations of microprocessors, where we’ll approach the finite size limit.” Added Lipa: “This fantastic result has the team very excited about the quality of data we’ll be able to obtain during the mission.”

In this study, called the Confined Helium Experiment, researchers use liquid helium — which conducts heat 1,000 times more efficiently than any other material — to take precise measurements of changes in material properties.

Television screens on Earth Friday and early Saturday continued to be filled with images of dendrite crystals growing aboard Columbia in a study designed to improve metals used in automobiles and jet engines. In the experiment, materials are melted and resolidified to observe the growth of dendrites. The study’s lead investigator, Dr. Martin Glicksman of the Rensselaer Polytechnic Institute at Troy, N.Y., described the video images transmitted from Columbia as “spectacular.” Glicksman added, “We’re obtaining extremely valuable, new information from the video and we’re looking forward to the next two weeks of science.”

Two measurement cycles were conducted Friday in the MEPHISTO furnace — a cooperative study by NASA and the French Space Agency to grow crystals in space. Researchers processed sample cartridges of the metal bismuth, with small additions of tin, using directional solidification — a common method for growing semiconductors and metal alloys. As the samples solidified during the test run, the scientists looked at the temperature, speed of growth, and shape of the crystals. Each sample then was measured three ways to identify the internal structure of the crystal — with each measurement involving both a freezing and melting cycle.

Researchers are seeking to understand how gravity-driven convection affects production of metals, alloys and electronic materials. “The information obtained from the first two freezing and melting cycles conducted Friday was excellent,” said the experiment’s lead investigator, Dr. Reza Abbaschian of the University of Florida at Gainesville. “The third cycle also provided excellent data.” He said the furnace facility — which is known as MEPHISTO, for Materials for the Study of Interesting Phenomena of Solidification on Earth and In Orbit — is working “beautifully.” It heated to 750 degrees Celsius, or 1,382 degrees Fahrenheit, for the sample processing.

Abbaschian said scientists “saw unexpected results. The crystal growth velocity for growing smooth crystals was expected to be about 1 inch per hour. But we saw the smooth crystal growth at one-quarter inch per hour. This unexpected result permits science to critically examine existing theories and modify theoretical models based on MEPHISTO results.”

Processing of the first sample in the Advanced Automated Directional Solidification Furnace began late Friday night. Three different lead-tin-telluride crystals were inserted into the furnace, designed for growing crystals in microgravity. The experiment, using precise temperature control, allows for gradual growth of large, nearly perfect crystals. The crystals are of different types of semiconductor materials which determine the speed and amount of information stored and sent by computers and high-tech electronics. The furnace facility, activated and checked out earlier Friday, was heated to 1,050 degrees Celsius — or 1,832 degrees Fahrenheit — in preparation for the first sample processing. Crystallization of the sample will occur about noon Saturday. It will take three days to complete processing of the sample. Knowledge gained from this study may lead to better crystals for electronic applications, as well as improved metal alloys for a variety of products on Earth.

Looking ahead, USMP-4 Mission Manager Sherwood Anderson said late Friday, “While difficulties with Spartan 201-04 may necessitate some adjustments to the USMP-4 timeline, anticipated changes should have no significant impact on our ability to accomplish our science objectives.”

In an experiment not directly related to USMP-4, the “eyes” of a system that could allow NASA spacecraft to automatically link up in orbit got an initial checkout Friday. Researchers at Marshall’s Spacelab Mission Operations Control Center in Huntsville received their first data from the Automated Rendezvous and Capture Video Guidance Sensor Flight Experiment during deployment of the Spartan 201-04 satellite Friday afternoon. “We got all of the data we had planned to get during the deployment phase,” said Dallas Pearson, chief engineer for the project at the Marshall Center. “And we hope to be able to accomplish all of our primary science once the Spartan is back on the robot arm.”

Early Saturday, as the Columbia crew slept, mission planners were determining the detailed flight plan and science to be conducted during the mission’s next 24 hours.

The next scheduled Public Affairs status report will be issued at approximately 7 a.m., Sunday, Nov. 23. For more information call the Spacelab Newscenter at Marshall Space Flight Center at (205) 544-0034 or visit the web sites: For USMP-4 payload and science information: http://liftoff.msfc.nasa.gov/shuttle/usmp4/ and http://science.msfc.nasa.gov/usmp4/usmp4.htm For STS-87 information: http://www.shuttle.nasa.gov

 

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