Certification of SRM1960: Nominal 10 μm Diameter Polystyrene Spheres (“Space Beads”)
Experimental, theoretical, and calculational details are presented for the three independent micrometrology techniques used to certify the mean diameter of Standard Reference Materisd 1960, nominal 10 μm diameter polystyrene spheres (“space beads”). The mean diameters determined by the three techniques agreed remarkably well, with all measurements within 0.1% of each other, an unprecedented achievement in the dimensional metrology of microspheres. Center distance finding (CDF), a method based on optical microscopy, gave a value of 9.89 ± 0.04 μm, which was chosen to be the certified mean diameter. The supporting measurements were done using metrology electron microscopy (MEM) and resonance light scattering (RLS). The MEM technique, based on scanning electron microscopy, yielded 9.89±0.06 μm for the mean diameter of the microspheres in vacuum, while the RLS value was 9.90 ±0.03 μm for the microspheres in liquid suspension. The main peak of the diameter distribution for SRM 1960 is nearly Gaussian with a certified standard deviation of 0.09 μm, as determined by CDF. Off the main peak, there are about 1% oversized particles and a negligible amount of undersized particles. The report gives a detailed description of the apparatus, the experimental methods, the data-reduction techniques, and an error analysis for each of the micro-metrology techniques. A distinctive characteristic of this SRM is that it was manufactured in microgravity aboard the NASA space shuttle Challenger and is the first commercial product to be made in space.
Standard Reference Materials :: Description of the SRM 1965 microsphere slide/
During the NASA Apollo missions to the Moon, several elementary experiments were performed to look at what happens when liquid materials are solidified without the effects of Earth's gravity. The results of these early experiments were very interesting, prompting NASA to conduct more sophisticated materials experiments at every opportunity. From the results obtained to date, many possibilities exist for new alloys, improved semiconductors, radiation detectors of Impressive characteristics, sophisticated high technology glasses, new pharmaceutical products, and other novel materials. Can these possibilities be transformed into practical, costeffective products for the benefit of mankind? The world's technologically leading countries are trying to find out.
The growth of materials processing in space - A history of government support for new technology
Development of a given technology for national defense and large systems developments when the task is too large or risky for entrepreneurs, yet is clearly in the best interest of the nation are discussed. Advanced research to identify areas of interest was completed. Examples of commercial opportunities are the McDonnell-Douglas Corporation purification process for pharmaceutical products and the Microgravity Research Associates process for growing gallium arsenide crystals in space.