There has been a lot of talk of a manned mission to Mars lately. President Bush recently stated we build a base on the Moon and work twards sending a
manned mission to Mars. Bush's father, on the 20th anniversary of the first manned moon landing, made a similar call for lunar colonies and a Mars
expedition. But the plan was prohibitively expensive -- an estimated $400 billion to $500 billion -- and went nowhere. No one knows what the new
venture might cost or how NASA would pay for it.
My question is how human physiology could withstand such a journey.
What are the human challenges of a long-duration mission to Mars. Can the psychological and physiological challenges of this trip be met?
We don’t just need to create an atmosphere that astronauts can survive, they need to thrive. It does us no good just to get the people there alive; we
need to ensure they get to the red planet in top physical and mental shape for the mission to be successful.
NASA scientists are considering a human mission, possibly as early as the year 2012. But the journey would be a long one, unlike any human space
mission ever undertaken. The trip to Mars could take as long as 26 months. Our current space vessels could not carry enough fuel to complete the
entire trip, so scientists must devise a way to manufacture fuel for the return trip. Food would also need to be grown or manufactured during the
But the greatest unknown is the human factor. Astronauts making the trip to Mars could not look back and see the Earth. How would they deal with the
psychological effects of the long, dark journey? Physical changes could play a role too -- exercise is less effective in space than on Earth, because
the force exerted by gravity is reduced. Exercising on a treadmill in space, for example, produces a force of only 50 to 70 percent of one's Earth
bodyweight. Finding effective ways to exercise is important to maintaining muscular strength and bone density during long stays in microgravity.
What are the effect of weightlessness on the human body?
Fluid redistribution is one of these effects. It occurs when bodily fluids shift from the lower body (where they normally abound due to the downward
tug of gravity) to the head and upper body. This redistribution of fluids is coupled with fluid loss. When the brain senses the increased volume of
fluid in the upper body, it interprets this as being an increase in the total volume of fluid in the body. The brain then responds by triggering the
excretion of fluids, making astronauts prone to dehydration.
The cardiovascular system. On Earth, the heart must operate against gravitational pressure to sustain blood flow. Under zero-gravity conditions, that
force is absent, causing the heart to lessen its pace according to the decreased demands.
Bone deterioration as a result of zero-gravity is extremely deleterious to an astronaut’s health. This deterioration occurs when the amount of
physical stress on bones decreases.
Similar to bone deterioration, muscles atrophy as a result of disuse. In space, actions and movement require considerably less exertion because the
force of gravity is practically non-existent. As a result, astronaut’s muscles become deconditioned.
The decreased production of red blood cells is another consequence of living in microgravity. Scientists are not sure why this occurs, but evidence
has shown that decreased exertion and prolonged weightlessness result in mild cases of‘space’ anemia.
Balance disorders can also result from extended exposure to zero-gravity.
The immune system is also affected by weightlessness. Astronauts become quite susceptible to illness when in space. The human immune response lowers
and the quantity of infection-fighting cells in the immune system decreases after prolonged exposure to microgravity.
Minor effects of weightlessness on the human body includes puffiness in the face, flatulence, weight loss, nasal congestion and sleep disturbance are
usually only minor (yet common) annoyances.
There are other hazards, too, Van Allen noted. For instance, the long-term effect of cosmic radiation outside the Van Allen belt is unknown. On a trip
to Mars and back, probably every cell in the body would be hit by an ionized particle or a proton, researchers say, and they have very little idea
what that would do. "If every neuron in your brain gets hit, do you come back being a blithering idiot, or not?" A round trip to Mars put the
exposure at 130,000 millirem over two and a half years. That is equivalent to almost 400 years of natural exposure.
Some psychological effects of being away on a mission of this length could include boredom, anxiety, sleep trouble, somatic complaints, anger,
disorientation, depression and an inability to perform their duties. One of the biggest concerns on a mission like this would involve sexual rivalry
between crew members.
I don’t see how we can overcome all of these issues. Remember the trip is likely to last more than two years.
[Edited on 26-3-2004 by kinglizard]