The paper discusses the potential effects of space environment on solidification; reviews the previous solidification experiments in space and suggests new-experiments. The proposed experiments in space include (a) breakdown of planar interfaces in transparent systems, (b) thermal perturbations ahead of interfaces, (c) dendrite spacings, (d) fragmentation of dendrites and their transport, (e) solute concentration profiles in castings, (f) maximum undercoolings in alloy melts under containerless conditions; ultrafine structures produced on freezing of highly under-cooled melts, (g) preparation of wires and ribbons from alloys; solidification in ultrathin films and (h) dendritic shrinkage.

Recent developments in fabrication of cast metal ceramic particle composites by liquid metallurgy techniques are outlined. Difficulties encountered in preparing cast composites in the ground environment (including non-uniform distribution and agglomeration of dispersed particles and relatively poor bonding between dispersoids and matrix) and how these can be overcome in a microgravity environment have been discussed. This paper also reviews experiments performed by various space agencies including NASA and ESA on fabrication of composites in space. Some new experiments concerning fabrication of cast composites like dispersion of submicron ceramic particles in molten metals, preparation of cermets with very large volume fractions of ceramic particles and dispersion of flake-type ceramic particles to achieve grain refinement have been proposed.