“…Certainly, under terrestrial conditions we can reduce convective transport by lowering the ratio between buoyancydriven convection and diffusion, for instance by decreasing the characteristic length of the system [22], i.e., using capillaries [23,24] or gels [25][26][27]. However, convective flow cannot be completely avoided inside X-ray capillaries of 0.2 mm inner diameter (the minimum crystal size for significant X-ray data collection of macromolecular crystals at conventional sources) and, with gels, the gel polymeric network may in some cases interact chemically with the protein molecules [28,29]. Nevertheless, the nowadays scarce flight opportunities, the existence of g-jitters and relevant values of residual accelerations on board the Shuttle [30] and the complex logistics associated with space experiments, makes it worth to develop research studies devoted to investigate in these on-ground analogs.…”