A Materials Scientist in Space
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sion I flew on in January 1990. You'Il share with me the expérience of performing research as well as retrieving the longduration exposure facility (LDEF) with a robotic arm. Some of you may remembèr the first footprint on the moon made by Neil Armstrong in 1969. I'd like you to realize that this event occurred over 20 years ago, and that it was approximately nine years prior to this footprint that a président of this country, John Fitzgerald Kennedy, committed us to that endeavor. He committed us to go to the moon not because it was easy, but because it was hard. It took the collective talents and dedication of many Americans in this country to get there. Materials hâve been called the enabling technology of engineering. I hâve a freshman textbook that says that, and materials certainly hâve enabled us to get to the moon, not just the first time, but to go back repeatedly. We went back many rimes during the 1970s, not just to demonstrate that we could achieve that goal, but to actually explore the moon, bring back samples, and exécute many scientific experiments. It was also during the 1970s that we committed ourselves to the first laboratory in space calied Skylab. We launched three différent crews to that lab, nine différent peuple. The longest créw remained thëre 84 days, the U.S. record in space. By contrast, we hâve been outdistanced by the Soviets, who hâve been in space for over a year. By the end of this décade, we hope the United States will hâve crews permanently manning a U.S. international space station. It was on Skylab that we really started to exploit a variable we've become accustomed to on the ground: accélération or gravity or g. In the Skylab experiments, we started to understand the complexity of fluid physics in a microgravity environment. Original studies of fluid physics in zéro gravity involved the delivery of liquid STS-32 missionspecialist Bonnie]. Dunbarworks with theFluids Experiment Apparatus (FEA) fuels to engines. The shuttle engines using on the middeck ofColumbia. liquid fuels in orbit must use preferentially wetted screens to bring the fuels to the heated ignition beds. However, the Skylab experiments went further by investigating the lack of convective effects on crystal The folloiuing is an edited version of NASA microscopes. So to me it's not an unusual growth and diffusion. Thermal convection expérience. In addition, materials stienAstronaut Bonnie]. Dunbar'sPlenary Address is suppressed under microgravity conditists and engineers are needed to operate at the 1990 MRS Ml Meeting. tions. In a zéro g or microgravity environin space. ment there is no buoyancy or sédiTonight I would like to do several things. I've often been asked, "Why a materials mentation. This allows us to mix very unuI'd like to talk to you about where we've scientist in space?" I hope my présentation sual materials. Surface tension dominâtes been in space, where we are, and where tonight will provide a little more insight on in everything we do, whether it is trying to we hope to go. I'U emphasize the materi
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