Exploiting the Resources: Water
One of the biggest issues in habiting Mars is obtaining a supply of water. In his book titled Mars: A Warmer, Wetter Planet, Jeffrey Kargel outlines the human need of water. He states that any single human might require up to 4kg of water per day for drinking. So theoretically, a 14-day mission on Mars might require over 600 kg of water for the health of the astronauts alone. However, hydration is not the only use for water in space. In an atmosphere mainly filled with carbon dioxide, electrolysis could provide a means to obtain oxygen. (Electrolysis is a process by which water is transformed into oxygen and hydrogen gas through the use of an electrical current; read more about it here). According to Kargel, a 10-person base would require about 100 kg/day of water to use for this function.
Long-term, self-sufficient settling of Mars would also require a steady production of agricultural elements (such as food, medicines, etc). Kargel estimates that the same base would require another 100 kg/day of water to account for the vegetation.
Overall, a short, 14-day mission on Mars would then require approximately 2 tons of water for the support of the astronauts on board. Keep in mind, however, that this water is only to be used on the planet; the astronauts will need additional water for the months of travel to and from Mars.
Where will the astronauts obtain water? Well, there are two main options:
1. Bring it with them – The ships will need to have enough room and power to carry this payload out of Earth’s atmosphere and into Mars. There is a narrow margin of error, and water will become a limiting factor to the length and completion of the mission.
2. Find it in somewhere space – Asteroids have been known to commonly carry ice and could potentially be mined to provide large quantities of water. Naturally, such an operation carries controversial risks which may outweigh the sought outcome. The logical choice would be to find water where the mission will take place: on Mars.
We know from both satellite images and rover exploration that Mars, like Earth, has polar icecaps which are made of frozen water, and there exists evidence that water used to flow on the surface in liquid form. Due its temperature and pressure, the surface of Mars no longer hosts flowing water. However, scientists believe that because of the way the ice caps were formed, there still exists liquid water under the surface.
I propose that we exploit this resource and find all of the water we need at the polar icecaps. Mining ice there would require rather simple technology and could be done autonomously. This would allow operation to continue without human presence in the planet. Once liquid water is reached, it could be pumped to the surface and used as needed. The biggest advantage is that ice, which would be a byproduct from mining, could be melted and used as water, too!
I pose the following question to the reader: It is clear that mining the icecaps would provide the resources needed to complete a mission of indefinite length on the surface of Mars, but what are the implications to the well-being of the astronauts? To the resources on Mars?
Resources (In-text included):
Your calculations may be an order of magnitude off if these missions used some of the water recycling technology already in effect on the ISS. Even so, that is still a lot of water needed.
As you point out, oxygen can be a problem too. Of course, terraforming the planet would help with both of these issues, but I guess you don’t want to wait around 100 years.
Comment by PlanetaryEngineer — November 28, 2010 @ 11:19 PM