Even the launch of a spacecraft can cause significant strain on the human body. Once a rocket ship clears the launch tower, the pilot and crew are already experiencing four times the gravity on the surface of Earth. Blood gets pushed down into the feet and falling unconscious becomes a serious risk. This is why astronauts launch with their chests facing up; it distributes the gravitational force over a larger surface area, diminishing the overall drop in blood pressure.

Astronauts also face extreme disorientation from the bones in the inner ear moving around. This can lead to nausea and vomiting within the first ten minutes of a mission. But their struggles are far from over here.

The lack of gravity in space can take a bizarre toll on the body. Fluids congregate toward the top of the body, resulting in swollen features. This can affect astronauts’ eyesight, including optic nerve swelling, changes to the retina and to the shape of the eye resulting from increased pressure inside the skull.

The lack of gravity also takes its toll on an astronaut’s muscles and bones. Living on the Earth’s surface translates to a constant level of resistance that keeps our muscles functioning and working. In space, astronauts’ muscles can atrophy, leading to weaker bones and an overall lack of strength.

Astronauts on long journeys also face sleep deprivation, diseases caused by radiation, and depression. Given the extreme stresses space-faring explorers undergo, it’s no surprise that NASA would look to an experienced agency for guidance. The Navy’s research is sure to help the space agency send astronauts off with the best possible tools to survive in deep space, and hopefully complete their long and arduous journey from Earth to our close neighbor in the solar system, Mars.