Since the first manned moon landing in July 1969, humans have looked to continue exploring and probing deeper into space. The effort has led mankind to look towards exploring other celestial bodies contained within our solar system. This recent search has largely been directed towards Mars, the fourth planet from the sun. Mars is a prime target for future human settlements due to it having the most accepting atmosphere of the other planets, and a good amount of in-situ resources—resources and materials that can be found on Mars—that can be used to help build habitats (Naser and Chehab 74). However, even with these benefits in favor of Mars and its colonization, there are still many factors that must be considered when planning a human journey to the Red Planet. As humans venture farther into space and missions are of longer duration, the risks of space become much more amplified. Ensuring the physical and mental well-being of a crew is of utmost importance for long duration missions into space, and without proper measures, no mission will find success.
The Martian environment presents two major challenges that will be analyzed in depth in the Martian environmental challenges section. The first of these challenges is an increased radiation dose that could lead to an increased risk of cancer and other health issues. The second challenge deals with different mental health effects stemming from confinement, a limited number of people to interact with, and an increasing distance from Earth—problems that could compromise the ultimate success of a mission (Pagel and Choukèr 1449). Both of these problems present different risks that have unique potential solutions to prevent them. Without proper precaution for each risk, a long duration mission to Mars will not be able to succeed, and the crews will be negatively affected in the process. This study includes an explanation as to why humans will ultimately have a successful and safe manned mission to Mars—even with the harmful challenges presented by the Martian environment—due to the careful design and consideration of their habitat.
The surface of Mars experiences a much greater magnitude of radiation than that of Earth due to the “absence of a magnetic field and to a low atmospheric shielding” (Horneck et al. 89). This means that astronauts living on Mars, even if confined to their living quarters, will receive very high doses of radiation that humans are not familiar with. The doses of cosmic ionizing radiation, radiation that travels from anywhere in outer space, on Mars can be up to 100 times as much as what humans experience living on the surface of the Earth (Horneck et al. 88). Solar UV radiation is also a very dangerous factor for humans living on Mars, as the short wavelength of UV-C is much more likely to penetrate the weak Martian atmosphere than it is Earth's atmosphere (Horneck et al. 91). This type of radiation contributes largely to humans developing cancers and post mission diseases as it can break down DNA and result in cell mutations and in cell death (Patel et al. 2). UV radiation from the sun can easily be blocked out by specific materials that can be used to build the astronauts habitat, working quarters, and space suit; however, cosmic ionizing radiation can only be blocked out by thick, dense materials—materials which would be hard and costly to send to Mars. Since these materials will have a low availability on Mars, it is important to plan where they will be located in a habitat, likely surrounding the sleeping and living quarters if available at all. UV radiation might also have a negative impact on the growth of plants on Mars, something which would be essential for any long term mission. For these reasons, the design and layout of the crews’ habitat, as well as the materials that can be used to block out UV radiation, must all be carefully considered; with proper measures, UV radiation can be countered and reduced, greatly increasing the rate of survival of astronauts on long term missions (Horneck et al. 92).
Another one of the most serious issues to consider when planning a mission to Mars is the mental health constraints that each member of a crew will experience. The current quickest mission possible to Mars would be around 380 days, and this would leave only 60 days for the crew to live on the surface and conduct experiments. A much more likely possibility would be a 1000 day mission, including the travel there and back, with around 400-500 days of Martian surface living. This extended period of time with an absence of a familiar social network of friends and family will present issues unlike any other humans have faced before (Manzey 782). Crew members will only be able to interact face to face with each other, a very limiting factor on the social health of humans. This can cause conflicts and fights between crew members to deepen and ultimately be another stressor holding a mission back from its full potential. During a mission to Mars, “isolation will be much higher compared to what is known from orbital spaceflight,” meaning that this will be a unique experience for the crew and one to which humans do not have all the answers (Manzey 785). Some of the problems that arise from a conflicting crew can be fixed by maintaining a habitat in which each member of the crew has their own personal space where they can feel safe and secure. By giving each person their own section in the living quarters, the crew will be more cohesive in times when a solution is needed for a problem, so this factor is something that must be considered when designing a Martian habitat (Manzey 785). Another factor that must be considered when planning for the mental health of astronauts is the separation of living and working spaces in the habitat. This helps to provide the astronauts with the familiar feeling of leaving for work and eventually coming back home later in the day, a feeling which will provide normalcy back into their lives (Kozicki and Kozicka 1999). If astronauts live where they work for an extended period of time, many negative effects will make themselves clear, including a decreased efficiency of work and an increased amount of stress and tension in intrapersonal relationships. These negative effects can be counteracted by separating the habitat into three different main areas, the living quarters, the work room, and the agricultural room. In doing so, crew members will feel a higher degree of separation between different parts of their day, and the habitat will feel in total bigger as they spend their time in different areas throughout the day.
In order to mitigate the negative effects of the Martian environment, a Martian modular habitat is one of the most popular design ideas for a future human base on Mars. Normal designs for modular habitats usually range from a series of 3 to 6 upright cylinders or domes that are connected via small hallway paths between each module. One reason a modular habitat is so popular among scientists is that it provides the crew members with many mental health benefits and helps to counteract some of the previously mentioned negative effects. In using a modular habitat, it is very easy to make a physical split between the astronauts' work, living, and agricultural spaces (Heinicke et al. 408). This also leaves them with room to personalize their surroundings and create a greater sense of their home, as each crew member will receive their own room in the living module. This model of habitat also allows for the protection of crews from many types of radiation events. Through the use of the right materials, specific radiations and their effects can be greatly reduced to the point where they are no longer a concern. Solar events are also a concern, but “solar events can be predicted…a week ahead,” allowing for a crew to gather in a designated safe spot in one of the modules with extra layers of material protection surrounding them (Kozicki and Kozicka 2002). This increased protection from radiation can also be used in the agricultural space to protect any food the astronauts are attempting to grow, promoting the long term success of the mission. Lastly, a modular habitat is also good at counteracting other dangerous events such as a fire in one of the modules, as any of the modules can easily be cut off from another by removing the hallway connecting them. This provides an extra layer of safety to the crew members on a long term mission. Overall, modular habitats on Mars can mitigate almost all negative effects observed in section 2 and can provide for a safe mission while on Mars. This will contribute to the success of the mission and create crew members that can return to living normal lives once they return to Earth.
Another popular solution for dealing with the harmful Martian environment is an underground habitat, an idea that has been proposed by opponents of building a standing surface structure as a Martian base. While this might be costly through excavation, it could be done on Mars through the use of lava tubes made by formerly active volcanoes. These lava tubes can be several kilometers in diameter due to the reduced gravitational field on Mars, and can “house protected habitats large enough for small compounds” (Naser and Chehab 84). It is most likely that any habitat built in a lava tube would need to be inflatable, as any other structure would be both too difficult and expensive to build underground. By building a habitat underneath the surface of Mars, crew members would be very protected from all types of radiation, even allowing the habitat itself to be made from less dense and costly materials. This benefit is very important for the survival of the crews, as the more time they spend protected from solar and space radiation, the longer the mission can be without a large magnitude of negative effects. The mental health of crew members is still something to consider though, as they would have to go with a reduced amount of natural sunlight. This can create unprepared for issues, and combined with the limited amount of personal space in an underground habitat, can harm the mission and its research. It would also be more difficult to separate the astronauts' work from their living quarters in an inflatable base, leading to decreased productivity and increased tension in the smaller environment. Altogether, an underground habitat can protect the crews of a manned Mars mission relative to their physical health; however, their mental health could be negatively harmed, ultimately making it a safe but less impactful mission.
From the research gathered, evidence points towards a modular habitat ultimately being the most successful model for any future manned missions to Mars. This conclusion was made based on the ability of a modular habitat to both protect its crew members from outside radiation and upkeep their mental health to the highest degree possible. The modular habitat can also be designed in a way that can protect the agricultural aspect of the mission, which is one of the most important aspects contributing to the overall long term success. While the underground inflatable habitat does have a few benefits that a modular model doesn’t, a modular habitat design is ultimately superior due to unknown and unresearchable elements of an underground habitat. The modular habitat is not completely perfect though, and it does present some challenges that must be considered if it were ever to be used on Mars. One of these considerations is the fact that since each module is connected by a thin, small hallway, the connections between modules are very susceptible to damage from Martian storms and dust. This could potentially cut off the crew's access to certain areas in their habitat that would have to be rebuilt. Another limitation of a modular habitat is that because of its size, part of it would need to be built with in-situ resources, meaning that further advancements in current technology are necessary in order to make this an efficient process. These negative effects do not outweigh the ultimate safety of the crew and the success of this mission that a modular habitat would ultimately provide. Even with these constraints and limitations, a modular habitat model would ultimately be the most successful option when compared to an underground inflatable habitat while considering the effects that the Martian environment might have on the crew.
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