A manned mission to Mars would be difficult, but a settlement is a whole other ball game. There are thousands of things that we need to think about and prepare for. Millions of variables make a settlement on the red planet near impossible. Radiation, food, climate and everything in between. This includes energy. Our overarching question being “Is a colony on Mars viable?” one of the main questions that we need to consider is that of energy. For a colony on Mars to function you will of course need quite a bit of power and bringing that power from earth will be inefficient, expensive, slow and outright stupid. So, in the following paragraphs I will be going through the ins and outs of generating electricity on the Martian surface.
Initial Sources of EnergyOne of the first problems we will encounter when we touch down on the red sand will be setting up base. Of course, Nasa and SpaceX will have thought this through and the landing craft that we came down on would serve as a temporary HQ. But the days of living in a dysfunctional space ship will be numbered. We will certainly have to expand beyond and build a sizeable colony to fit all the future colonists and facilities that we need in order to survive, while still having plenty of living space for the inhabitants to be comfortable.
In order to build and power all of our Martian facilities and living space we will need a large amount of energy. The way we create such energy will depend on a few factors: price, efficiency and difficulty. For an energy source to be viable for use in the interplanetary colony it will need to be cheap to send it to Mars, it will need produce lots of electricity and consume minimal resources at the same time and to be easy to set up quickly for the settlers since they don’t want to spend all their time doing one thing when they can be doing something more important. Some concepts for initial energy sources on Mars include Elon Musk’s concept from SpaceX that is compared to a colourful whistle from a kid’s birthday party, in Elon’s words “that party thing where you inflate it and it rolls out”, the idea for this is to have a really big one of these made of really thin solar panels, so when it rolls out the solar array will already be set up and ready to go. One of the advantages to this is the fact that since it will be filled with air and likely very light, moving it around into the optimal positioning in terms of access to sunlight with surely not be too difficult. Other methods for creating initial sources of energy on Mars include NASA’s more favourable option, nuclear energy, they have designed a small reactor called “Kilopower”, also known as KRUSTY (Kilopower Reactor Using Stirling Technology). The advantages of nuclear power are that it’s lightweight and reliable. Other sources of energy either require too much fuel (making them to heavy) or can’t be counted on in all seasons. Solar power, for example, relies on consistent sunlight. That’s something that’s lacking on Mars, since it depends on the time of day, the time of year, the location on the planet surface and how bad the planet’s dust storms are, which can last for months. Nuclear energy operates regardless of the weather or time of day. Also, the number of solar panels and batteries required would once again make the rocket to Mars extremely heavy (requiring more fuel for take-off). Kilopower works like a Stirling engine, it has a sealed cylinder with one part hot and the other cold. The working gas inside the engine is moved by a mechanism from the hot side to the cold side. When the gas is on the hot side it expands and pushes up on a piston. Kilopower reactors range from 1 kilowatt (about enough to power a household toaster) to 10 kW. To effectively run a habitat on Mars and create fuel, about 40 kW would be needed, so NASA would likely send four to five of the reactors to the planet’s surface to start with. Long term Sources of Energy Once humans have touched down and set up base, they’ve got the power running and are completing their missions and research, they will find that their small nuclear generators won’t do the trick in the long run and will have to start setting up their long-term solution. Creating enough energy to support a group of colonists that could reach into the hundreds will be no simple task and luckily the brains at NASA have already made a solution for their problem.
In the first couple months our nuclear generators will be able to produce around 50 to 100 kilowatts, but too support a Mars colony we will need to produce upwards of 10 megawatts of power, that’s ten thousand kilowatts. For that amount of energy, we will need to dig deep and harness the power of the planet, using geothermal energy. There are three ways for generating geothermal energy on Mars, dry steam, flash steam and binary cycle. The one that we would most likely use on Mars and is the most common on earth is dry steam. Dry steam plants work by piping hot steam from underground reservoirs directly into turbines from geothermal reservoirs, which power the generators to provide electricity. After powering the turbines, the steam condenses into water and is piped back into the earth via the injection well.
But why can’t we use solar, nuclear, wind or radioisotope thermoelectric generators (RGTs). With Mars being so far away from the Sun and solar power generation on Mars certainly wouldn’t be our first option. RTGs are fine for generating tens of watts but are not suitable for powering Martian villages with hundreds of residents, much less cities with thousands of residents that Elon Musk plans to put there. Wind energy on Mars would not be an amazing idea seeing as the atmosphere of Mars is 2% of that on earth. Being hit with a 200 km/h wind would feel as though some one had brushed you with a feather. Proper nuclear power production would likely be a long-term option when Mars has a more robust infrastructure. And that of course leaves us with geothermal energy.
Scientists believe that there is a suitable water table for geothermal power production less than a kilometre from the surface. Wherever this water table is, it will definitely be prime real estate for the Martian colony. The planet’s low gravity, a third that of Earth, should make it much easier to drill on Mars. That’s because the planet’s lower gravity will compact the soil less. And then once hot water is brought to the surface, it would be flashed to steam and used to power a turbine to generate electric power. Mars’ low atmospheric pressure will also allow steam to be much more fully expanded before it is condensed.
The rovers on Mars have detected methane, which is either the product of hydrothermal activity, or of bacteria living in geothermally heated environments. If it is there, deep drilling is also the key to finding past or extinct Martian life. If we are able to drill all the way down to get the heat, then we will also have to work out some way to get the heat out. On Earth that’s been with water, but that’s surely in short supply on Mars. With the amount of CO2 trapped in Martian ice, it is likely that we can melt that down and use it as our exchange fluid in the generator.
Once we get about five-hundred kilowatts of nuclear power, we will be able to start drilling and begin work on the 10-megawatt geothermal energy plant.All of our educated guesses still depend on how accessible Martian geothermal energy proves to be. If it’s easy enough to get at, we’ll get at it with equipment from Earth. If it’s difficult to get at, we may have to wait until we can turn Mars’ iron oxide to Martian steel for drilling pipe. The most likely outcome is that the colonists will have to drill almost 10 kilometres down to reach the pay dirt. The biggest challenge we will face is how we can drill with low power since you can only drill as fast as the power you have.
It’s likely the tech will develop to get geothermal energy from deep within Mars. But it is just as likely that we won’t be able to take the Earth technology straight to Mars. It should be around twenty years after the first humans arrive on Mars that we will have geothermal energy up and running.