Energy: the Achilles heel of deep space exploration 

Energy: the Achilles heel of deep space exploration

Electrical energy is quite literally the lifeblood of any potential Mars base. With the flip of a switch, our modern technology can create oxygen, hydrogen and methane from materials/gasses on Mars, print habitats, and grow food… but none of this happens without power. A base in an austere environment like Mars will simply cease to exist without the electrical capacity to run the heaters, compressors, life support, communication equipment and dozens of other critical systems required for daily life.  Electricity is life. 

Electrical power and our ability to generate it on Mars is one of the critical six factors required for a settlement on Mars to succeed. A 2015 NASA study estimated that a Mars base would need at least 35 to 40 kW electrical power generation capability. In this article we will go over the power requirements for a base, potential power generation technologies and the near future options which could be put into use within the next decade. 

Our current level of technology offers several solutions that range from next generation nuclear powered generators to innovative wind and solar options. These available options pose interesting planning and engineering challenges as each has inherent pros and cons.  

Below is a deeper look at each potential power generating technology and the Pros and Cons behind implementation:  

Nuclear:

Pros: Proven reliability and impervious to weather or blackout periods.

Cons: Expensive, still in development, potentially dangerous and politically divisive.

Nuclear power has been used as far back as the Voyager probes and currently powers the Curiosity and Perseverance rovers.  The rover’s power supply is essentially a nuclear battery called a Radioisotope Thermoelectric Generator (RTG) which converts the heat from a nuclear reaction directly into electrical power via a thermocouple. This power cell is optimal for missions where solar power may not be feasible. The biggest downside of an RTG is that the power output is in the 100 Watts range which only works for smaller craft and is not sufficient for a full base. In 2018 NASA and the Department of Energy expanded this design and built a working demonstration model of the Kilopower Reactor Using Stirling Technology (KRUSTY).  This fission based reactor uses nuclear fuel to generate heat (like the RTG) which is converted to electrical power through the use of a stirling engine.  This next generation system is designed for the moon and Mars and expands the power output from 110 Watts to 10 Kilowatts. In 2022 NASA awarded the initial contracts to expand this design in the next decade to a single 40 KW reactor to meet the energy needs of a moon/Mars base.

Solar:

Pros: Proven, inexpensive, dependable.

Cons: Susceptible to weather/dust/darkness.

Solar is one of the more tried and true power generation options that has been used on Mars for decades; just not at the scale a base will require.  To generate 40KW with Solar panels it would require roughly 4500 square feet of panels on Mars. This is based on a rate of 10 KW per 525 square feet on Earth and adjusting for Mars being further from earth and only getting ~40% of the sunlight.  As the Insight and Opportunity lander/rover demonstrated, dust on Mars is a significant issue that will require either tech or human intervention to ensure power generation levels stay within the 35-40 KW range needed. Additionally, to allow surge capability and a buffer for night time use, solar will need to be paired with some form of energy capture and storage system like the Tesla Powerwall.

Wind:

Pros: Potentially inexpensive and can generate power day/night.

Cons: Airborne Wind Energy system is unproven technology in low density atmospheres, under development and potentially susceptible to severe weather impacts.

Wind power is not normally an option proposed for Mars because the atmosphere is very thin with approximately 1% the density of the Earth’s. However, as NASA’s Ingenuity helicopter has proven, aerodynamically generated lift and sustained flight on Mars is possible using current technology. This demonstrator proves flight is possible which opens up possibilities not previously considered. One novel idea is an Airborne Wind Energy System called Kite Power that uses a parachute styled airfoil or an ultralight glider kite tethered to a generator.  The kites fly in figure eight patterns alternating one leg against the wind causing the tether to spool out out and spin the generator, and then when the kite flies the reverse leg the tether retracts.  The concept was further refined for a Mars application in 2021 by a development team for the European Space Agency who designed a system that used a 540 square foot kite system designed specifically for Mars. The proposed system produces enough power to augment solar power during high load periods or power the base at night when the panels are not producing electricity.  While this type of system has never been tested on Mars, the average wind speeds on Mars between 10-20 mph should provide enough lift to make a lightweight version of the system possible.  Even more compelling, dust storms that would completely block solar power could actually be a benefit as the Curiosity Rover has measured winds that peak around 60 mph during storms.  

Whether it is nuclear, solar, wind or a mix of all three… Power and a solid plan to produce it are essential to a successful base on Mars. Getting the right mix to ensure high output continuous power will be the key to ensuring long term settlements on Mars succeed.