Applying photon correlation spectroscopy in space

Transparent models of condensed matter systems can be studied optically using photon correlation in the microgravity environment of the Space Shuttle or the proposed Space Station. Design and packaging becomes more critical than for Earth-bound equipment. Also, to generate enthusiasm enough to assure its expensive deployment, the system must have a target performance at least as good or better than that possible on Earth. Additional properties must be robustness, small physical size, low weight and power consumption, retention of alignments and a well-controlled thermal environment for the specimen. Confidence may be built by careful design and extensive testing. Optical design must give versatility without unacceptable compromise. Performance must confirm known physics, and separate new phenomena from artifacts of the instrumentation or measurement process. Effectively applied risk analysis must prevent potential defects from compromising the entire mission, preferably by substituting 'graceful degradation'.