Most scienceScience fiction films and television shows of the past century have featured people walking on the floors of spaceships and space stationsSpace station, much as they would on the surface of Earth. Their vehicles appear to have standard Earth gravity. However, one of the most significant challenges for ‘real’ humans living and working in space is the absence of gravity. Long-term exposure to a zero/micro-gravity environment can have an extremely negative impact on the human body. This includes atrophy of muscle, reductions of bone mass, weakening of the cardiovascular system, and fluid shifts in which fluids shift from the lower body to the upper body causing numerous symptoms (for example, it has been determined that astronauts exposed to microgravityMicrogravity on long-duration spaceflights can suffer deleterious effects on the eye’s optic nerve).