Building-out Mars: Powering Our Colony

With enough energy we can do just about anything. On Earth, water treatment and distribution, provision of sustainable irrigation for farming practises and distribution of energy to all people can and must be done.

Deptford Power Station London, 1952. Credit: The Northcliffe Collection/ Associated Newspapers Limited

On Earth, we have had a long time to develop our current energy system, moving from wood, to more energy dense material such as oil, gas and nuclear. And even now we are transitioning to a more sustainable basket of energy technologies each year. It has become abundantly clear that renewables, led by Solar and Wind are the clear leaders in this space, on a cost and feasibility perspective. Very often in the media there are announcements of certain countries running their "longest streak on renewable power ever", or "longest run without firing up a coal plant". 

Power Generation Maintenance / Operations worker inspects some rotating equipment. Credit: DRAX

We are moving into a strong energy disruption to generate a more sustainable, distributed and fair energy system. This is in line with the 2030 Sustainable Development Goals. By developing a more resilient, flexible and decentralised energy system, along with efficiency increases, we have a real shot at meeting them.

UN 2030 sustainable development goals. Some appear more visible in the media than others. This blog focuses on energy generation, distribution and adjacent goals. Credit: UN

On Mars, our colonists have had zero hands-on experience, relying only on data and analysis returned from Mars via long-distance communication with Perseverance and Curiosity rovers, the Hope mission from UAE. 

Being 1.5 AU out from the Sun, our colonist crew on Mars has much lower intensity light reaching their community. In fact, Mars receives about 40% less irradiance at the surface than Earth.

Above Earth's atmosphere, approximately 1300 w/m2  of solar radiation is received. However, due to Earth's atmospheric composition of light-sensitive molecules (think Ozone and radical species) of some of this energy (roughly 1/4 of this) is absorbed. The remaining 1000 W/m2 irradiance arrives overhead at the equator at noon. On the surface of Mars, for the equivalent time and location, 590 W/ m2 is received. This is a significant shortfall and a blow to powering our crew's expeditions and living arrangements.

This makes use of solar panels for energy generation a more challenging prospect. Even with increasing efficiencies in solar technology, reducing costs for panels, a drop of 40% of prospective power generation - and that is when the sun is shining, with the air relatively dust free.

With the crew needing oxygen, methane fuel for flight, water and a sustainable power source (nuclear units will only do so much for so long), there will need to be reliable power. To achieve this, the crew can have a suite of energy technologies working together to give uninterrupted power.

Given that this equipment all needs to be shipped from Earth, the design will need to be optimised.

As beautiful as it is - this Arizona dust storm is vastly different to the storms on Mars. These storms are much more localised - not extending across the North American continent. Credit:

During the month long martian dust storms which happen annually - although not fixed in one season of the year - like Earth weather patterns - the sun can be blocked out for weeks at a time. During these storms, the day and appear as night, yet this is the 'mini' dust storm which can be foreseen. These storms can blanket areas with continental proportions. A pop culture reference of such dust storms was seen in the Blade Runner remake with Ryan Gosling.

However we don't even need to go into the future - rather the past in Australia. In Sydney 2009 - residents were treated to a deep Orange-Red sky - courtesy of sand-storms blowing off the interior of the country. 

Eerie loss of depth in field of view - Sydney Harbour 2009. Credit: u/LadderOne

Escalating this to a higher level - every 3 Martian years (5.5 approx. Earth years), the sandstorms can aggregate and encircle the whole planet in a dusty cloak for weeks. 

Considering these challenges, the Martian colonists have some tough design choices to make when they consider how to power their enterprise on Mars.

But first, let us start with the other end of the equation - considering the use case, and the actual requirements that the Martian team will have when they arrive on Mars. A useful model for this could be the International Space Station. 

On (Oct. 4, 2018) the ISS photographed by Expedition 56 crew from a Soyuz spacecraft. Shot taken after undocking. Credit: NASA/Roscosmos

Already in orbit for approximately 23 years (The station celebrated the 20th anniversary of the launch of the first element Zarya in November 2018.) - albeit always growing toward the current configuration. Here there is some excellent data around the energy that is required. For convenience, we can assume the energy input to the station can be considered to be approximately equal to the input of the electrical output of the solar panels extending far and making up a good portion of the extent of the station. 

Approximately 2,500 m2 of solar panels grace the wings of the ISS. From these, the crew receive anywhere from 84 - 120 kW of DC electrical power. However, this isn't a constant power generation rate. Even being above the atmosphere as mentioned earlier, the ISS doesn't receive constant solar exposure. Indeed the crew experience 16 sunrises and sunsets per day as they maintain orbit approximately 400 km from Earth. In addition - the crew also experience great extremes in temperature outside of the Earth's atmospheric protection - with 'night' time temperatures of (-) 200 degC, seeing (+) 200 degC when the ISS is exposed fully to solar radiation.

With this power, the crew can power their experiments in all the orbiting laboratories there. In addition, the ISS has ammonia radiators - used to dissipate these extreme heat temperatures, and indeed heat from the equipment inside.

In the next article we will cover the loads on this power system, and build out our understanding of power requirements for a Martian mission.

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