variety of scientific backgrounds (biologists, physicists, engineers, etc.), it is unlikely that the crew expertise in a given increment will match the large variety of experiments taking place. In addition, through 2005, the primary occupation of all crew members will be ISS assembly. In this situation, any technical innovations that permit the automation of routine tasks or the robotic manipulation of experiments will greatly increase efficiency. The task group also notes that another way to maximize the scientific output of the ISS-based research would be to allow investigators to participate directly in experiments. Scientists could spend time on the ISS as short-term residents or travel with shuttle crews during routine supply and transfer missions. This approach might not be immediately realistic owing to the stringent demands on crew time and expertise during ISS construction. However, as the assembly phase approaches completion, the demands on personnel time should become more flexible, allowing greater crew involvement in research projects and the possibility of having nonastronaut scientists aboard the ISS.

PROTEIN CRYSTAL GROWTH

Since the beginning of the NASA protein crystal growth program in 1985, a variety of equipment has been used to grow and observe crystals in the microgravity environment. Useful and innovative hardware development on systems for the ISS continues today. A complete description of the equipment that is or will soon be available is provided in Appendix A. Options for investigators range from liquid-nitrogen-cooled dewars capable of holding large numbers of samples but providing minimal environmental control or observation to refrigerated trays aligned with Michleson-Morley phase-shift interferometers. The task group was particularly impressed with the prototype of the X-ray Crystallography Facility (XCF), which can grow and cryopreserve a reasonable number of samples as well as provide important monitoring capabilities, such as video feedback and X-ray diffraction data. While this approach of monitored growth appeared to the task group very promising, it is important to recognize that in some situations large numbers of samples might be an effective alternative to a few carefully chosen and observed samples.

The Hardware Development Process

It is clear that NASA's microgravity crystallization program and its associated crystallography hardware are not yet mature. However, it is important that researchers interested in exploiting the microgravity environment on the ISS have access to hardware that is state of the art and the most efficient available. To achieve that goal, collaboration and communication between the various laboratories involved in hardware development should be established. Many of the key pieces of hardware so far have been innovated by external investigators, so it is not necessary to have centralized hardware development within NASA. Multiple developers will encourage variety and creativity, while preventing NASA from getting locked in to a single hardware approach. However, the efforts of hardware developers must be coordinated and communication between them improved to ensure that different programs are not producing instruments with duplicative capabilities and that technological advances are quickly shared and integrated into all equipment where appropriate. In addition, since the modular structure of ISS racks will permit instruments from multiple hardware designers to coexist, it is important that the systems be compatible to allow experimenters to take advantage of the full variety of equipment (e.g., samples could be grown in one type of hardware yet monitored by another developer 's system). Finally, the most vital step in hardware development is for the research community at large to have input into the instrumentation development process, as cutting-edge science problems can drive the development of innovative new technologies. An example of the critical nature of the collaboration between science and engineering for effective use of large facilities can be seen in how synchrotron sources and the instrumentation for beam lines have evolved most successfully when bureaucratic structures are not allowed to divorce scientific goals from the work on the technology needed to explore those goals.

The most important characteristic of NASA-sponsored hardware development should be flexibility. If a variety of equipment types are available, investigators, with the help of hardware developers and NASA staff, can match their experiments to the instruments best suited to their needs and goals. A modular approach should be emphasized so that individual systems can be upgraded as technology advances. Finally, NASA needs to be prepared to abandon completed hardware or hardware under development if it becomes clear that better systems or



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