Scientists have been collecting data for years concerning people who have spent time up in space. Over the years, they have determined that during short-term stays of about six months have a definite physiological effect.
The immune system suffers when a person is isolated over time. This can cause astronauts to be more prone to infection by viruses, bacteria, and fungi. Allergy symptoms may also increase. Because of this, astronauts headed to Mars will need to bring along heavy duty drugs that they would not mix together until they had arrived. (Sounds like a job for a good chemist?)
And it’s not just infections they’ll need those drugs for. Other aches and pains may also abound.
A common, early occurrence in 40 percent of all astronauts is space sickness — a form of motion sickness that is only experienced in space. The symptoms include nausea and vomiting, headaches, dizziness, and general weakness and discomfort. Usually this condition lasts only a few days as the astronaut adapts to the change in his environment.
The blood circulation during life in space begins to get used to flowing much more easily because gravity is not affecting its function. The heart beats faster and the blood pressure rises, causing astronauts to experience puffy faces, nasal congestion, and headaches. This also causes their legs to get thin, and as we now know may even lead to a stiffening of their arteries
A bit odder change occurs to the shape of red blood cells themselves. The shape becomes more spherical, and fewer cells remain within the bone marrow. The cell shape returns to normal once the astronaut returns to Earth. However, no studies of missions over a year long have been made, nor do we yet know how Martian gravity, which is less intense than Earth’s, will affect them.
The change in circulation and subsequent muscle loss, as well as bone loss over time, can be a cause for concern when considering a longer mission. The Mars-bound astronauts may need a ship that could somehow lessen the burden by producing artificial gravity, and be equipped with exercise gear meant to keep the limbs and body in shape. But that’s not the most pressing problem.
Without a shield to keep radiation bombardment from getting inside, any spacecraft sent to Mars might as well be considered a microwave oven considering how cooked the crew would be by the time they arrived. They will be likely to experience flashes of white-hot light behind their eyes along the way thanks to such unhealthy visitors as solar flares and cosmic rays. If they did manage to survive thanks to shielding, they might still be bombarded enough to eventually develop cancer, heart disease, and nerve or brain damage
Here is a video of NASA discussing the MAVEN mission and their thoughts on reaching Mars:
[image courtesy of NASA/JPL-Caltech]