Human and rodent ground-based models of space flight environments.

Today, as we stand on the brink of the 21 century, access to space is still limited and flight costs are still high. Flight opportunities of any kind are rare, but at the same time it is clear that a new era is dawning. The completion of the International Space Station (ISS) will provide mankind, for the first time, with an international, permanently manned outpost for research in space. Looking ahead further, practically every national or international space agency is studying approaches for a return to the moon or an initial manned mission to our “sister planet” Mars. All these circumstances clearly indicate that human presence in space will be a continuing and growing event well into the new century. When we look back at the 40-year history since the first man travelled through space, many questions regarding the effects of space flight on human beings have been examined and answered. Yet our knowledge is still far from complete. More questions remain to be asked and answered, and as usual in science, for every question we answer a host of new questions arise. To answer those new-born questions there is great need for more research opportunities to be undertaken in both the traditional arena of space flight operations, and the often over looked ground-based models that simulate microgravity.