Gravity, defined as the force that attracts two bodies to each other, exists everywhere in the universe. Since spaceships and the International Space Station are in perpetual free fall above the Earth, their forward motion equals the speed of its “fall” towards the planet. Thus, astronauts in space cannot feel the pull of gravity. Rather, they feel the sensation of weightlessness.
Astronauts, who are in space for several months to a year, are not only affected temporarily but also in the long term. Astronauts experience a disruption in their proprioceptive system, so they feel like their limbs are not attached to their bodies and they lose sense of direction. This is because the human body relies on the vestibular system within the inner ear to act as its motion sensor. The vestibular canal has sensitive accelerometers that feed the brain signals to indicate motion and direction. Without the feeling of “falling” produced by gravity, human bodies feel limp and hard to control. The effect usually leads to immediate disorientation: many astronauts suddenly feel themselves upside-down, for example, or even have difficulty in sensing the location of their own arms and legs.
Over time, astronauts who constantly feel this disorientation develop Space Adaptation Syndrome, which is a severe form of space sickness. Nausea, vomiting, and poor concentration are just a few of the syndromes that may develop from the feeling of zero gravity. Although astronauts will eventually adapt to the floating feeling, it is their brains rather than their stomachs that do the adapting. The brain learns to ignore the confusing signals from the vestibular canal while visual signals become the main source of signaling information for the body to balance. Thus, in space, it is extremely important that astronauts have visual stimulation; wherever their feet are placed signals the direction “down”.
Since visual stimulus becomes the sole, essential factor in an astronaut’s sense of balance in the space shuttle, we propose a solution that would combine the use of biological properties of water and materials with the need for a visual stimulus to create an ultimate illusion of gravity.