We have previously discussed what resources are necessary to sustain an offworld colony on Mars, but not the specific technologies that are needed to provide for those needs. Developing or improving these technologies have filled the lives of many scientists and engineers for the past half century, and will enable the lives of Mars colonists.
In this post, we will do our best to provide an introduction to the key components of human survival beyond Earth. We’ll also provide links to resources for readers interested in digging deeper into these particular topics.
Before humans can live on Mars, we must first get there. Before we can settle Mars permanently, we must be able to send explorers with the resources to explore Mars and return to Earth safely. The first challenge is that no existing rocket has the capacity to carry humans to Mars in a single launch. At present, many launches would be required to assemble the needed equipment and fuel in near-Earth space prior to a Mars mission. The more pieces a mission must be launched and constructed from, the more challenging and expensive this orchestra of orbital assembly becomes. Additionally, a larger portion of your launch mass must be dedicated to carrying out meeting and mating of separate portions to assemble a whole mission.
The Saturn V Moon rocket was large enough to send people and cargo to Mars, but it has been discontinued since 1972. By 2020, at least two heavy lift rockets are expected to be flying: NASA’s SLS and SpaceX’s Falcon Heavy. Heavy rockets such as these would allow human Mars missions to be constructed from just a few independent launches, or for hardware to be sent to Mars from a single launch. Once these rockets have proven themselves, humanity’s ambitions can be unleashed toward Mars. The Falcon Heavy has taken its first step in proving itself by sending the test payload ‘Star Man’ towards Mars in 2018.
Cost-effective and reliable rockets must be available before a sustained human presence can be established on Mars. This is no easy task, because these two goals can be at odds with each other, and it takes many tests and launches to demonstrate reliability. At present, SpaceX is landing the first stage of their rockets and launching them again on subsequent missions. As SpaceX is able to refine this technique, launching things into orbit will get substantially cheaper, at a tenth or less the current price.
Any explorer sent to Mars must also have access to food, water, and enough fuel to return to Earth. By providing some of these supplies by using resources already on Mars, we become capable of doing more with less. We would be able to send more astronauts and scientific equipment to Mars, and they would be able to stay longer. There is something powerful about the idea of living off the land of Mars, just as explorers have been doing on Earth for millennia. Nobody leaves the driveway with everything they may need for a cross-country trip. When we can provide these vital resources reliably and efficiently, we can move from exploration to colonization; from habitats to homes.
You may not be accustomed to thinking of Mars as a place rich with resources, but it certainly is. Mars has rich mineral and material resources, in an abundance found nowhere closer to Earth. Today, serious organizations are preparing to mine asteroids, and large ones may hold a trillion dollars in mineral wealth. Mars has a trillion times that potential. Before humans used them, the Earth had mineral wealth accessible on the surface. On Mars, these resources still lay upon the surface, waiting for us to take and shape them. Mars has an atmosphere which is not hospitable or harmful to life. In comparison, Venus has air rich in acid and so hot that it is inhospitable to even hardened machines. Mars’ atmosphere is accessible anywhere and can be harvested more easily than ground resources. Gravity is very important to both our bodies and technologies. The longest a human has spent without gravity has been a year, and re-adjusting took weeks. Even making and using a toilet is a very involved affair without gravity. One of the greatest challenges of getting people to Mars is keeping them healthy during the many month interplanetary flight without the influence of gravity.
Resources are one thing – gravity, another – but what about water, food, and fuel? The atmosphere of Mars contains abundant carbon and oxygen in the form of carbon dioxide. Its soil and ice caps also contain a surprising amount of water. With these in-situ (native, local) resources and a source of energy, it is possible to produce breathable air, drinking water, and rocket fuel. If we don’t make these things on Mars, every ounce of food for the crew and litre of fuel for the voyage home will need to be launched from Earth and carried safely to Mars’ surface. This would be extremely heavy and therefore expensive. Key thinkers on the colonization of Mars, including Robert Zubrin and Elon Musk, agree that using Martian resources is vital for any mission, and have published their plans for how to accomplish this.
Actionable proposals already exist for securing water on Mars.1 Since water can largely be recycled, the question of whether we bring our own drinking water to Mars or extract it there is not a crucial one for the viability of human exploration on Mars. Unfortunately, the same cannot be said for food. The ability to produce food on Mars is crucial for viable long term settlement. In fact, it can provide substantial benefit for even relatively short missions.2 The first Martian explorers will likely conduct experiments to refine and demonstrate this technology. Humanity must first prove that food can be produced safely and reliably before explorers and colonists can rely on Martian food at all. Martian agriculture could also accept human waste as an input, thus serving as part of a system for recovering nutrients and water.
There are substantial challenges to growing food on Mars. The Martian atmosphere is much thinner than Earth’s, and plants are accustomed to growing in very biologically active soil. Much research is already being done on this front in simulated Martian environments, which will help us develop this precious technology more quickly and cost effectively than if we waited to experiment on Mars.
Experiments 3 4 have shown that Martian soil will likely be an adequate growing medium, with some known challenges.5 Other experiments have examined the challenges of growing plants in a low pressure environment. Plants that can thrive with low pressure and low oxygen would allow large greenhouses to be built on Mars.6 This would be much cheaper than oxygenating and pressurizing them to match human requirements.7 Keep in mind that pressurized structures are under constant strain, requiring that they be very strong. Developing plants and growing techniques that are capable of producing food at Mars’ ambient pressure would be very handy for the long term habitation of Mars, but we do not need to have that worked out before our first trips. Even growing food in a pressurized environment (like a crew module) for our first food growing operation on Mars could still be a wise move because less food would need to be imported from Earth. Establishing this experience early on would go a long way to laying the groundwork for rapidly growing, thriving Martian cities.
Keeping people alive during a trip to Mars and back is a challenging task. However, scientists and engineers have explored the underlying problems in great detail and have designed promising solutions. If fuel, water, and food can be secured from the in-situ resources of Mars, then larger, longer, cheaper, and more frequent missions become possible. In short, humans can start exploring Mars in the near future. The challenges for doing so have been outlined above, and the techniques are already in development. These bold initial missions will accomplish much more than exploring Mars, they will establish the foothold necessary for permanent Mars habitation. The technology and techniques described here are also applicable to crossing interplanetary space for other human exploration missions, such as to Venus or to the asteroid belt and its rich resources. These technologies are a crucial part of humanity’s coming of age in the solar system.
In our next article, we will discuss the greater challenges of establishing permanent human habitation and civilization of Mars.
- Wiens, Jordan, Forest Bommarito, Eric Blumenstein, Matt Ellsworth, Toni Cisar, B. McKinney, and B. Knecht. “Water extraction from Martian soil.” In Fourth Annual HEDS-UP Forum, p. 11. 2001. [↩]
- It is, after all, a very long way home even after the mission crew leaves the surface of Mars. If Martian-grown food could even partially feed the crew on their voyage home, it would mean substantial savings on launch weight from Earth. [↩]
- Perchonok, Michele H., Maya R. Cooper, and Patricia M. Catauro. “Mission to Mars: food production and processing for the final frontier.” Annual review of food science and technology 3 (2012): 311-330 [↩]
- Davies, Fred T., et al. “Growing Plants for NASA–Challenges in Lunar and Martian Agriculture.” Combined Proceedings International Plant Propagators’ Society. Vol. 53. 2003. [↩]
- Navarro‐González, Rafael, et al. “Reanalysis of the Viking results suggests perchlorate and organics at midlatitudes on Mars.” Journal of Geophysical Research: Planets 115.E12 (2010) [↩]
- Richards, Jeffrey T., et al. “Exposure of Arabidopsis thaliana to hypobaric environments: implications for low-pressure bioregenerative life support systems for human exploration missions and terraforming on Mars.” Astrobiology 6.6 (2006): 851-866 [↩]
- At its thickest, Mars’ atmosphere is a 20th of Earth’s. [↩]