Space Beads
Dale Kornfeld of NASA Marshall Space Flight Center was conducting experiments aboard the space shuttle to determine the effect of microgravity on chemical reaction rates of emulsion polymerization, as well as on the morphology (shape) of polymer microspheres grown in microgravity. The first experiments of the Monodisperse Latex Reactor (MLR) were conducted in 1982 aboard space shuttle flight STS-3 and resulted in microspheres as large as 5 m in mean diameter. A subsequent experiment on a later shuttle flight, STS-6, produced particles of 10 m mean diameter. In 1984, the NBS group obtained samples of the 5 m and the 10 m materials and did a detailed intercomparison between the space-made particles and earth-made particles of similar composition. In both cases, the space-made materials were found to be superior in terms of individual particle sphericity, narrowness of size distribution, and, importantly, in particle rigidity. An agreement was then made between NASA and NBS for NASA to provide a sufficient quantity of the 10 m material to make up 600 5 mL vials containing liquid suspensions of the polystyrene microspheres for use as an SRM.
...In 1985, SRM 1960 was first offered for sale to the public through the NBS Office of Standard Reference Materials (OSRM), making the SRM the first commercial product to be manufactured in space (SRM-1961, the nominal 30 m spheres, was the second space-made product). The sale of the space beads was reported in hundreds of newspapers, magazines, and television/radio news stories around the world, from the NewYorkTimes to the CBS Nightly News to ABC's Good Morning America. The work was also featured on a National Public Radio program and on an Australian science show, Beyond 2000. Later on, SRM 1960 won an IR-100 award from Research & Development magazine for being among the top 100 products of 1985. Over the years, SRM 1960 has proven to be a valuable tool for the calibration of particle-sizing instruments in the United States and around the world. Samples have been purchased by dozens of U.S. and foreign companies for use as primary particle-sizing standards. These companies include not only the makers of particle-sizing standards and instrumentation, but also every day users who need to maintain accuracy and traceability of their measurements. Among the primary users are major pharmaceutical companies, Fortune 500 petrochemical and chemical companies, small-to-midsized biomedical instrumentation companies, particle standard supply houses, and numerous firms, of all sizes, involved in the measurement of particle size. Several U.S. Government and non-profit labs, including NASA Ames, Battelle Northwest, EPA, FDA, Los Alamos, Sandia, and the USGS have also purchased SRM 1960. In the international arena, the material has been used by research laboratories in Australia, Austria, Brazil, Canada, England, France, Germany, India, Italy, Japan, Korea, Mexico, Norway, Spain, Switzerland, and Thailand. Sales of SRM 1960 average about 25 vials per year through the NIST OSRM. The OSRM also offers for sale another version of the space beads, SRM 1965, which are standard microscope slides with small patches of particles in both regular arrays and micro-sphere chains. These have been used throughout the world for educational and training purposes, as well as to satisfy the needs of those who wish to own something made in space. In addition to OSRM, the micro-spheres are also sold through the European Community's Bureau Communautaire de Reference (BCR). The demand for SRM 1960 is spurred, in part, by its incorporation into several document standards in the United States. For example, the U.S. Pharmacopeia, in its test entitled 'Particulate Matter in Injections,' specifies the use of SRM 1960 for calibrating the liquid-borne particle counters used in the test. As a water-quality standard, SRM 1960 is listed by the National Oceanic and Atmospheric Administration (NOAA) in its compilation of Standard and Reference Materials for Marine Science as a physical standard for the assessment of water and sediment quality. The particles have also found application in the monitoring and assessment of air quality, especially with regard to the Environmental Protection Agency (EPA) PM10 standard that specifies a cutoff of 10 m for the aerodynamic diameter of particulate emissions from motor vehicles, smokestacks, and other industrial emission sources. In the medical field, SRM 1960 has been valuable as a calibration standard for blood-cell counting and sorting, as the mean diameter of the SRM is very near that of human red blood cells. Thousands of hospitals and medical testing laboratories throughout the U.S. use blood-cell counters to check for sickle cell anemia, Tay-Sachs disease, and other blood abnormalities, and SRM 1960 helps to ensure the quality and accuracy of such tests. SRM 1960 will, undoubtedly, find more applications in the medical field as biotechnology and medical diagnostics become more pervasive in our daily lives. In addition to the above applications of SRM 1960, other areas of scientific research where the material has found use include: electron microscopy; chemical chromatography; powder metallurgy; ceramics; food processing; photographic films; and basic particle research, among many others. The rigid demands of ISO9000 will likely increase the importance of particle-sizing standards such as SRM 1960, as companies become more concerned with quality control, conformance assessment, and reliability issues. ...
Certification of 10 m Diameter Polystryrene Spheres (“Space Beads”)
