Greetings from Palmia Observatory
Well the 23rd annual Mars Society Convention was held online this year from October 15-18, 2020. It was quite different from the in person meeting previously held in Irvine, CA, but we can still make some brief comments for those Martians of you who could not attend online.
The theme this year was "Rising together to Mars." The president of the Mars Society, Robert Zubrin, kicked off the convention, which had multiple events and presentations by scientists and experts. My summary comments try to beginning with some of what we know about Mars from robotic landers and orbiting spacecraft and then move on to what is required for humans to get to Mars and land there and survive and end up colonizing the planet and becoming Martians.
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| Mars Society 23rd annual convention poster (Source: The Mars Society) |
The theme this year was human exploration and colonization of Mars. This will build on previous robotic explorers who are currently on the surface or in orbit, but will require much larger landing vehicles. For robotic landers in the 1-2 ton range, the thin Martian atmosphere can absorb about 99% of the kinetic energy, but human landers will require more advanced techniques.
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| Curiosity Mars Rover Update (Source: Abigail Fraeman, Deputy Project Scientist, JPL) |
For the moment, let's delay talking about how humans will survive the journey to Mars, with all of the solar and cosmic radiation bombarding the spacecraft, but begin with what are the requirements for humans to live on and colonize Mars. We can see immediate needs for oxygen, water and power and eventually food. What is required so that Mars could be a self supporting colony of individuals without continual resupply from Earth?
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| Essential Requirements for Mars colonization (Source: Prashanth Sharma, UPES) |
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The Curiosity Rover has been climbing up Mt. Sharp, investigating all of the interesting geology along the way. We see evidence of flowing water on the surface, which raises the possibility of water below the surface or near the poles.
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| Essential Requirements for Mars colonization (Source: Prashanth Sharma, UPES) |
So, while humans couldn't survive in the atmosphere without a spacesuit, the presence of carbon dioxide is a good thing because it can be a source to make oxygen and carbon bases rocket fuels like methane, CH4.
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| Essential Requirements for Mars colonization (Source: Prashanth Sharma, UPES) |
How do you get oxygen out of carbon dioxide? Well, when the latest rover, Perseverance, lands on Mars it carries a prototype converter, called MOXIE, to evaluate how effective is it to extract the oxygen from available carbon dioxide.
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| MOXIE ISRU prototype installed on Perseverance Rover (Source: Michael Hecht) |
One of the primary needs for making oxygen from Mars rather than transporting it from Earth is for the rocket launches from Mars to return to Earth. To launch a crew of four from Mars requires about 25 tons of oxygen, while the oxygen required for breathing for a 150 day mission for four astronauts is just 1/2 ton. The fuel required for the return flight is on the order of 7 tons of liquid methane, which is considered the fuel of choice because it can be manufactured on Mars.
Ok, so maybe oxygen can be produced in-situ on Mars, but what about finding water? The search for water on Mars begins with what is known about the ever changing climate on Mars. Mars is subject to wide swings in its orbital obliquity. The reason seems to be, unlike the Earth which has a large enough moon to stabilize the variation in obliquity to just a narrow region, the Martian moon is not large enough to do this. So, with the wide range of obliquity, Mars has a wide range in solar insolation at the surface, which has big impact on the availability and possibility of liquid water on the surface.
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| Climate change on Mars due to obliquity changes (Source: Carol Stoker, NASA Ames) |
Radar observations of the Martian surface show evidence of ice at various locations. Ice and liquid water have different radar reflectivity than Martian regolith and can be measured from orbit. This map shows the possible locations for ice that is just below the surface.
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| Potential of ground ice from radar measurements (Source: Carol Stoker, NASA Ames) |
Whether ice or water is stable on the surface or slightly below the surface depends on the atmospheric pressure and the temperature from solar insolation. This next chart shows possibility of liquid water, again just below the surface. Liquid water is not stable on the surface and would evaporate in the sunshine.
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Ok, so there seems to be available sources of water and ice at various locations on Mars, mostly dependent on the latitude, with more ice and water nearer the poles. Maybe you would have to dig or drill a little bit to find it, but it could be there.
So, we have a chance of mining and making the oxygen and water that humans would need for survival without resupply from Earth. But, let's return just a little bit to the radiation hazards of making the trip to Mars. This slide compares the radiation risk for previous ventures into orbit and to the moon.
The Earth's atmosphere provides a lot of protection from solar radiation and the magnetic field also deflects low speed charged particles from the sun. Higher energy cosmic rays just pass right through that and strike the surface. You can see that the trip to Mars is the most dangerous compared to earlier trips.
It turn out that for the journey to Mars you would be surrounded from radiation coming from the sun too but cosmic radiation comes from every direction. But when you arrive and land on Mars, the radiation effects are almost half of what if was during the journey because Mars itself blocks cosmic rays from on direction and you also have nights and days.
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| Radiation risks comparison between missions (Source: Sarah Baaout, sck cen) |
Next, the issue of growing food on Mars has to contend with the thin atmosphere as well as the higher radiation environment. To grow food on Mars will require a controlled environment, which means a lot of materials and infrastructure will have to be invested in the project. A lot of support systems are need to control the environment and provide water for the plants. Many different types of watering and feeding the plants are being considered and evaluated.
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| Growing food in controlled environment (Source: Nikita Dvay, HabitatMarte.com) |
Studies have been done on the radiation tolerance of plants. In this next screenshot you can see that plants are more resistant to radiation damage than us weak humans. In previous conferences we have seem various proposals to use mirrors or fiber optics or even artificial lighting to provide a safer lower radiation environment for growing plants if needed. The lesser amount of special infrastructure needed to safely grow a food supply will make surviving on Mars easier.
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| Some plants are not as sensitive to radiation damage (Source: Nikita Dvay, HabitatMarte.com) |
Now we have already seen that to get water and oxygen we will need a lot of power. Power will be needed to run the ice thawing or drilling or mining operations and it will also be needed to make oxygen and rocket fuel from the available carbon dioxide. One source of available power is solar power, but the solar energy from the sun is 1/2 that available compared to the Earth and the weather and dust on Mars is a special risk. There is much interest in using nuclear power systems because of the higher power density and less reliance on the variability of solar power.
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| Potential Space Power Sources (Source: David Poston, www.spacenukes.com) |
The day/night cycle imposes severe requirements on the power system. Especially for the Moon, where the night time when there can be 14 days of darkness. For solar power systems, the shortfall of solar insolation would need to be met by energy storage or other power sources. The case for small nuclear power plants is growing stronger as research shows its feasibility.
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| Power requirements between Moon and Mars (Source: David Poston, www.spacenukes.com) |
This summary slide shows some of the issues and the history of power systems in space.
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| Power requirements between Moon and Mars (Source: David Poston, www.spacenukes.com) |
There also many ongoing architectural studies about how to construct habitats on Mars and how they might be configured to support all of the necessary infrastructure and still provide an environment that humans could safely live. Separately, the Mars City Design event and contest involves artists and architects in preparing plans and concepts to show what life on Mars might be like.
In this screenshot you can see various domed type structures, fabricated mostly from materials extracted from Mars. You can see structures to support agriculture and water and waste systems and habitats for living. Other studies look more to living under the Martian surface in pre-existing lava tubes or caves.
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| An example of Martian community and architecture (Source: Barbara Belvisi) |
Finally, some out of the box thinkers are also considering what the economy of Mars might be, or better maybe has to be in order to make the colony a self sustaining colony. Here are some dollar numbers for your consideration. Hmm, I guess if you were planning to make just a one-way trip you could save yourself about $250k?
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| Some studies look at economics of Mars inhabitation (Source: Robert M) |
So, there were many other interesting topics that showed up in the convention, but that is all of my comments. So, this brings us to the end of our summary of the events at Mars Society 2020 conference. This sign off performance was by Bob McNally with his latest version and rendition of the Mars song, with the words to the chorus shown in the slide screenshot. Can't you see yourself just singing these words to the chorus as we go "We're moving on to Mars, On to Mars!"
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| Singing the Mars song (Source: Bob McNally) |
Until next time, here from our burrow, stay safe, as we recover more of our freedom,
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