Prospector Base has a sick bay. In Red Dragon, Trudy Trudeau was treated for a gunshot wound there. Looking ahead, Mars explorers and colonists will face a unique set of medical challenges and health risks. What perils will those first arrivals face? And what sort of facilities will they need to survive while up to 170 million miles from home?
"Floating in a most peculiar way" may be a transformative personal experience, but it comes with downsides. The effects of zero-gravity will be acute on the months-long transits to and from Mars. Bone density loss resembling osteoporosis begins on exposure and increases with duration. Recovery can be slow. Astronauts returning from the International Space Station to Earth can take two or three years to return to their pre-flight bone density. It is unknown at this time if the stay on Mars' 0.38 g's would continue the loss of bone mass or simply delay the recovery.
Zero-gravity reduces muscle mass, including heart muscle. Without resistance to gravity, muscles atrophy. The heart works less to maintain blood pressure. Blood volume also drops as the body adapts to zero-g. Returning astronauts experience a condition called Orthostatic Intolerance. The weakened heart pumps less blood to the brain, resulting in light-headedness and fainting when standing for extended periods. This will presumably be a risk on Mars, though the low g environment there can be expected to present an intermediate risk to full Earth gravity.
The best mitigation for bone density loss and muscle atrophy is to mimic gravity during the transits to and from the Red Planet, an engineering feat yet to be seriously addressed by either NASA or SpaceX. The addition of resistance and cardio equipment for astronauts on the International Space Station moderates, but does not completely eliminate, the effects of zero gravity.
Mars orbits the sun 40 million miles outside the orbit of Earth, receiving 57% less solar radiation. But because Mars' atmosphere is so thin, the flux of UV light reaching the surface is roughly equal to that on Earth at sea level. However, the percentage of the shortest wavelength ultraviolet light, UVC, is much higher.
UVC is the most damaging form of UV light but is nearly completely filtered by Earth's atmosphere. Little or no exposure on Mars would result in severe sunburn and other associated UV damage such as skin cancer and cataracts. Fortunately, very few missions contemplate sunbathing astronauts.
The same suits that protect explorers against the extreme cold and near-vacuum will safeguard against UV exposure. Visor materials already in use in Earth orbit will sufficiently protect users on Mars. However, mission planners must account for rapid ultraviolet light degradation of biological compounds used for pressure suits, habitats, and equipment. The sudden fragility of the Prospector Base dome material in my upcoming book, Blood Moon, is attributable to UV degradation.
Ironically, the efficacy of UV and environmental protection of Mars dwellers could lead to vitamin D deficiency. Humans will take vitamin D supplements on Mars, as astronauts currently must do aboard the International Space Station.
Space is swarming with high energy particles (both charged and uncharged) and rays (i.e., photons). Long term exposure to these particles can lead to radiation sickness, cardiovascular disease, cognitive impairment, cancers and leukemias. But thankfully for us, Earth possesses two features that limit the flux of cosmic radiation that reaches the surface–a strong magnetosphere and a relatively dense atmosphere. Mars unfortunately lacks both. The level of cosmic radiation reaching the surface of the Red Planet is approximately seventeen times that of Earth.
As I noted in my October 2021 issue, the best shielding material for cosmic ray particles is high density polyethylene. The high hydrogen density of this resin provides an effective, though not perfect, shielding material used on the ISS. The top protection for astronauts on Mars will be to site their base underground, either utilizing natural features such as lava tubes, or by constructing permanent subterranean structures.
While it may be possible to adequately shield habitats and vehicles, the suits worn for extra vehicular activities must balance bulky shielding with the need for dexterity. Astronauts must sacrifice some protection from cosmic rays to be able to perform tasks while on the surface. But given the severity of health consequences, they will need to limit EVAs during mid-day when solar particles will be at maximum intensity. Colonists may need to take prophylactic doses of iodine to minimize effects.
Because of the profound isolation on Mars, screening equipment for cancer, heart disease and cognitive impairment must be brought along. Anyone stricken with these diseases will need to be treated in place. The length of time to return to Earth, plus the rigors of the trip itself, makes treatment in place the superior option if the patient is to survive at all. The mission medical equipment must include mini labs that can generate designer pharmaceuticals, and possess the basic raw materials to do so.
No doubt about it. It's cold on Mars. Even in the garden spot of Hellas Planitia, summer nighttime temperatures can dip down to minus 50 degrees F. Midwinter minimums can drop as low as minus 160degrees F. For reference, carbon dioxide dry ice freezes at minus 109 degrees F. Exposure to such temperatures would be lethal in seconds. Any failure of the heating systems in suits or vehicles could result in rapid onset of extreme frostbite.
Treatment for mild cases is relatively simple–water baths of gradually increasing temperature. But severe frostbite often requires surgical removal of damaged tissues. Prevention will be paramount, but any mission medical facility must be equipped for surgeries. Medical staff must be competent to perform such life-saving procedures.
The dust on Mars is incredibly fine, and pervasive. It will be tracked inside bases and vehicles on the suits worn on extra vehicular activities. If not controlled, airborne particles in these enclosed environments could pose serious health risks. Perchlorates, ubiquitous in Martian soil, are highly reactive oxidizers that can cause lung irritation even in low concentrations. Silica is another known pulmonary irritant and carcinogen. Other heavy metals and toxic compounds found in closed depressions on Earth (think Death Valley) are also likely to be present in Martian soil.
Astronauts cleaning up after an EVA may wear a respirator. Suits and hand-held equipment carried inside should be washed, and the effluent properly treated to ensure fugitive dust does not become airborne. Treatment for exposure could range from steroids or other anti-inflammatories for lung irritation to various chelating agents for arsenic and heavy metal poisoning.
Add to the above list of health risks: cuts, burns, broken bones, and electrocution. Because of a gravity environment, people will fall, vehicles will crash or roll over, accidents will happen. Electrical equipment will require maintenance. In spite of everyone's best efforts, someone will get hurt. And there will need to be an ample supply of first aid and trauma gear to deal with it.
If we are sending people to Mars, we expect them to return to Earth alive. They will need the equivalent of an army field hospital, plus specialized diagnostic, pharmaceutical and exercise equipment. Due to mass and volume constraints, everything must be miniaturized and optimized for light weight. Most materiel must be prepositioned, including the basic habitat and vehicles. The flight bearing humans will carry food and water to keep the crew alive for the two-to-three-year mission duration, plus exercise equipment, trauma treatment supplies and pharmaceuticals.
To have "the right stuff" to survive the rigors of the Red Planet and return safely home, Mars visitors must possess more than grit and superb health. They must be medically self-sufficient, with world-class clinician(s), diagnostic and pharmaceutical equipment. Think of that the next time you reach for a Band-Aid® in your medicine cabinet.
For Further Readinghttps://davidson.weizmann.ac.il/en/online/sciencepanorama/dangers-zero-gravity#:~:text=In%20the%20absence%20of%20gravity%20there%20is%20no%20weight%20load,mass%20within%205%2D11%20days.
https://www.nasa.gov/mission_pages/station/research/station-science-101/cardiovascular-health-in-microgravity/https://en.wikipedia.org/wiki/Ultraviolet#Solar_ultraviolethttps://www.smithsonianmag.com/air-space-magazine/do-space-station-crews-take-vitamin-pills-180949990/#:~:text=Zeke%20Mazur%20of%20Imperial%20Beach,Johnson%20Space%20Center%20in%20Houston.
https://www.sciencealert.com/these-martian-features-could-serve-as-natural-radiation-sheltershttps://www.nasa.gov/feature/space-radiation-is-risky-business-for-the-human-bodyhttp://marspolar.space/files/hellas-basin-preliminary.pdfhttps://en.wikipedia.org/wiki/Martian_soil
