 10, K minus 9, 8, 7, 6, 5, 4, 3, 2, 1, solid rocket ignition, and lift off, lift off of Columbia on a voyage to the future. The isothermal dendritic growth experiment, or IDGE, is a microgravity material science experiment planned to fly on board the space shuttle Columbia as part of the United States microgravity payload mission. It is a fundamental materials research experiment to help better understand and correlate what parameters affect the size and shape of crystals which determine the final properties of materials. IDGE was conceived at the Rensselaer Polytechnic Institute in Troy, New York, which is responsible for the science and dendritic growth chamber development. Dr. Martin E. Glicksman of RPI is the IDGE principal investigator. Well, what we hope to accomplish in the IDGE experiment is to be able to observe the growth rates and crystal morphologies of dendritic crystals as they form and develop in the microgravity environment of low earth orbit. This experiment will constitute a basic check of the physics theories of dendritic growth and provide some critical data for the assessment of the scientific concepts that form the framework of our understanding of this rather important metallurgical phenomenon. The experiment will take place inside this experiment apparatus container which will be mounted on the support structure inside the cargo bay of the spacecraft. The experiment apparatus is a miniaturized automated space laboratory that was designed and built by a team of engineers at the NASA Lewis Research Center in Cleveland, Ohio. The specific objective of this space experiment is to improve the quality of metals through the study of succino nitrile. This material was chosen because it mimics the behavior of iron in its melting and solidifying process with one additional advantage. It is clear and transparent. Metals are not transparent. We cannot see what is happening to their structure when they solidify. If we were able to better understand what is occurring to the crystalline structure of the metal, we would stand a much greater chance of improving its qualities. That then is the objective of this space experiment. This containment vessel houses the device through which we will attempt to learn and understand the internal changes taking place inside these solidifying materials. Inside the containment vessel of the automated space laboratory, there is an isothermal bath. It is a two-gallon tank filled with a mixture of ethylene glycol and water in which the temperature can be maintained to within two-thousandths of a degree. It has a heater coil in it and a small impeller down at the bottom to assure good mixing of the ethylene glycol and water so that there is an even temperature distribution within the vessel. The isothermal tank also has four windows on it to accommodate the necessary photography. And to the tank are two 35-millimeter cameras which record the dendritic growth and two slow scan television cameras. The television cameras monitor the dendritic growth and activate the 35-millimeter cameras when growth in the experiment begins. The rack around the tank provides a place to mount the circuit boards. The experiments will take place inside this growth chamber which was conceived and developed at Rensselaer Polytechnic Institute. The chamber is constructed out of stainless steel and glass. Their misters extend from the bottom of the growth chamber up into the volume of succino nitrile. They measure the temperature of the dendritic growth with an accuracy of two-thousandths of a degree Celsius. Succino nitrile, or SCN, is encapsulated in the volume of the growth chamber. The SCN is 99.9% pure and was chosen because it mimics the behavior of iron in its melting and solidifying process. SCN is a solid at room temperature and melts at 58 degrees centigrade. That's 136 degrees Fahrenheit. Now let's take a closer look at what we expect to achieve and learn through these experiments. During the solidification process, dendrites are formed. Dendrites are branching tree-like crystals that form during industrial metal production. Understanding and correlating what parameters affect the size and shape of this crystallization will help us to understand and subsequently be able to predict the final properties of many metals, alloys, and superalloys. And how we propose gathering that information is through this isothermal dendritic growth experiment. The growth chamber is filled with SCN material and contains a stinger that is used to form the dendrites. First, the SCN material is melted by raising the temperature of the isothermal bath. The molten SCN is then cooled to just below its freezing point by reducing the temperature of the isothermal bath. The SCN will not solidify at this temperature because it is such a pure material. The stinger is a hollow shaft which is also filled with the polymer SCN and extends right into the volume of this SCN material in the growth chamber. Using thermal electric coolers, additional chilling is started at the top of the stinger shaft which is located outside of the growth chamber. Once the stinger cools too far below the freezing point, the SCN inside the shaft solidifies. The solidification process moves down the shaft and pops out at the stinger tip which is being monitored by the slow-scan television cameras. When the SSTV and associated software spot a dendrite forming, the 35mm cameras are triggered. The cameras are set to expose six pictures at regular intervals as the dendrite grows to fill the field of view. This entire process is monitored in Huntsville, Alabama at NASA's Marshall Space Flight Center to assure that the experiment is progressing as expected. In the Payload Operations Control Center, or POC, the growth velocity of the dendrite is measured. If necessary, timing of the experiment can be adjusted and remelted to repeat the experiment as often as might be required. After the flight, the 35mm photos will be analyzed for size and shape information. These are dendrites which were grown on Earth. You can see the effects of gravity in their formation. There are no arms or branches on top of this dendrite. As this material solidifies, it gives off the heat of fusion. The heat works upward, causing the top of the sample to stay a little bit hotter. As a result, the bottom solidifies a little sooner than the top. As the bottom cools, gravity is creating a force which speeds up the downward growth of the arms of the dendrite. These convective forces confound the effect of dendritic growth and make it difficult to understand the formation of these dendrites. The space environment will simplify this process and enable us to better understand the process of crystallization. The dendrites will be more symmetrical because gravity will not be distorting the solidification process. These experiments will be most beneficial to metal manufacturers. They will provide a fundamental understanding of how dendrites grow so that we can better understand how to make predictions of the quality of an end product. If we understand the process, we can improve it. If we can improve it, we will be able to reduce scrap and produce stronger and more ductile materials. It will be possible to achieve whatever kind of property may be needed to satisfy the consumer. Everyone making products out of any metal will benefit from what is learned from these experiments. In the future, automobiles, airplanes, ships and many other metal products will be a little better and somewhat less expensive because of the isothermal dendritic growth experiment.