Human Exploration of Mars is Decades Away
Human Exploration of Mars is Decades Away
Mark Davis MD
Death is waiting for any voyager who attempts a trip to Mars in the next decade. Recent schemes by super wealthy individuals to send a contingent of people to the Red Planet, in the near future, are foolhardy and misdirected. Scientists have not discovered the means to protect the human body from radiation hazards of deep space. In the six months it takes to reach their destination either corpses or the near dead will arrive. Every organ system in the body will become dysfunctional. Presently there is no protective systems known which can inhibit the deteriorating effects of long-term space flight on human physiology.
Weightless environments create less need for the supporting structures of bone and muscle. These systems diminish rapidly unless challenged through exercise. As time moves on muscles, especially of the legs and back, become smaller and sometimes atrophy to a point that makes them useless. More interesting the types of muscle fibers change. Endurance slow twitch muscle is replaced with rapid fire fibers which prevents the body from performing heavy tasks. The ability to stand, walk and climb steps is difficult for those returning from months spent on the International Space Station (ISS). Bones fair even worse.
When gravity is reduced to extremely low levels bone repair and replacement is minimized. Over time bone mass decreases substantially. Leg bones, hips and the spinal column are especially hard hit, losing as much as 1.5% of their mass per month. Bones become porous, fragile and fracture more easily. Doctors note this is a form of premature osteoporosis. Cortical bone erodes more rapidly than the inner matrix. Bone metabolism is usually in fine balance. Osteoblasts build up bone components, while osteoclasts deconstruct them. In space the preponderance of bone metabolism is loss of structure by osteoclasts. Consider that a person on the ISS for 3 to 5 months takes 2 years to regain bone mass lost. Currently a journey to Mars takes 180 days. Bone loss during that time period could reach catastrophic levels. One more reason deep space flight should be delayed.
Radiation is the single worst factor confronting astronauts as they leave Earth’s orbit. On or near the Earth’s surface the atmosphere filters out harmful radiation.Moving beyond the outer layers of this planet’s protective cover are the Van Allen Belts. These are zones of charges particles held in place by the Earth’s magnetic field. Extending out as far as 30,000 miles they shield this planet from the destructive forces of high energy particles which could wreak havoc on human physiology. More to the point without their filtering effects life would cease to exist. ISS visitors who remain in orbit for at least 6 months receive five times more radiation than if on the ground. As the length of stay in orbit increases astronauts receive exponentially more exposure to these harmful rays. What are effects on the body?
Elements of the immune system, when bathed in the effects of radiation, face eventual collapse if exposure is prolonged. Antibody response is slowed as lymphocytes are severely injured. Chromosomal damage prevents keys cells in the system from reproducing. These T cells enable the body to fight off infection. As the number of immune cells are reduced infection can spread unabated. Long-term, cancer in its many formats, occurs because the body cannot inhibit the growth of these noxious cells. NASA is aware Cosmic rays change the brain’s structure. From premature dementia to electrophysiologic detriment the mind ability to function normally ceases. In deep space, beyond Earth’s protect shields, solar radiation is more penetrating with much higher dosages delivered to body tissues. In addition to neurological problems bone marrow is affected which depletes the source of many blood cell types, causing death of the individual from aplastic anemia.
Much worse than a collapsed immune system, dementia, cataracts, bone marrow suppression and changes in the fluid content of the body is premature aging. Deep space studies in this area are conclusive with no present treatments to slow the effects of this type aging known. Essentially every system in the body is affected. NASA is investigating countermeasures including enhanced exercise devices. This research is ongoing. Presently there are more questions than answers.
Billionaire entrepreneurs will knowingly risk livesin their quest to place astronauts on the surface of Mars. Human physiology is fragile, easily challenged and cannot bear up against the hazards noted in this article. These well-known facts are being minimized by those rushing to complete the end game. Maniacal obsession by the super wealthy to venture to the Red Planet in less than a decade will only lead to disaster. Mars’ environment is hostile and unwelcoming to humans. Early astronauts will not have to worry about this because they will never reach the surface. NASA’s time table is realistic, the schedule of those who are obsessed is not. In twenty-years humans may have the knowledge and wisdom for interplanetary flights. At this point in history even returning to the moon is challenging. Let’s hope level minds decide on the longer time table, if not a dark future is ahead for the bravest and foolish amongst us.
