  Here we report the results of microgravity experiments performed on the
International Space Station (ISS) to study crystallized, metastable colloidal
liquids in the region of the hard sphere phase diagram that has been found to
be glassy on Earth. Using confocal microscopy, we observed the self-assembly of
high density, three-dimensional colloidal crystals from micron-size hard
spheres suspended within a fluid medium. The largest face-centered cubic (FCC)
phase measured 27 x 1.5 x 0.15 mm. From a practical aspect, the fact that a
single, topological defect-free FCC colloidal crystal can be grown in
microgravity and the crystal returned from orbit suggests new routes for
manufacturing colloidal devices, particularly optical elements in space.
