The Microgravity Research Division of NASA funds materials science research through biannual research programs known as NASA Research Announcements (NRA). Selection is via external peer review with proposals being categorized for ground based research or flight definition status. Topics of special interest to NASA are described in the NRAs and guidelines for successful proposals are outlined. The procedure for progressing from selection to a manifested flight experiment will involve further reviews of the science and also of the engineering needed to complete the experiment successfully. The topics of interest to NASA within the NRAs cover a comprehensive range of subjects, but with the common denominator that the proposed work must necessitate access to the microgravity environment for successful completion. Understanding of the fundamental nature of microstructure and its effects on properties is a major part of the program because it applies to almost all fields of materials science. Other important aspects of the program include non-linear optical materials, glasses and ceramics, metal and alloys and the need to develop materials science specifically to support NASA's Human Exploration and Development of Space (HEDS) enterprise. The transition to the International Space Station (ISS) represents the next stage of the Materials Science program.