Some of the achievements of small scale comet simulation experiments and modeling are described, which led to a need of large scale simulation experiments such as KOSI. As part of the KOSI effort, a new machine is being built at Tel Aviv University to produce large samples of gas-laden amorphous water ice. These large scale experiments area preparation for the coming CRAF and ROSETTA missions to comets. ¿American Gephysical Union 1991