Settling Mars (With A Little Help From Andy Weir)
Mars tugs at the human imagination like no other planet. With a force mightier than gravity, it attracts the eye to the shimmering red presence in the clear night sky.”
– John Noble Wilford, Mars Beckons
The red specter of Mars has intrigued people throughout recorded history. Mars was the Roman god of war and second only to Jupiter in the Roman pantheon. In 1877 , the Italian astronomer Giovanni Schiaparelli believed he saw a system of straight lines on the surface of Mars. He called these “canali”. A true translation of this would be “channels”. However, many interpreted this to mean canals, and the interpretation stuck — until we got better telescopes.
The first real pictures of the Martian surface did not become available until the Viking mission in 1976. It was abundantly clear that Mars was cold, dry and virtually airless.
In spite of the seeming hostility of Mars, there is great interest in establishing a permanent human presence there. In some cases, this is seen as human destiny — and a logical next step for our inquisitive civilization of explorers. Others view Mars as insurance against an extinction level event that kills all life on Earth. Whatever the motivation, putting humans on Mars will be difficult and dangerous.
Andy Weir’s book “The Martian”, and the movie made from it, sparked renewed enthusiasm for manned exploration of Mars. Elon Musk says we will soon be able to buy seats for a trip to Mars. I would wait to see how that works out before signing up. Why do I say that? It is really hard to get to Mars. It is even harder to survive once you get there.
Why is it so hard?
One of the coolest things about “The Martian” was how true it is to engineering and science. The author did a great job representing many of the challenges Mars explorers will face. Andy Weir effectively served up physics, chemistry, and engineering with the snarky and sarcastic humor of astronaut Mark Watney.
So, I am going to ask Mark Watney to help me explain some of the difficulties we will face in colonizing Mars.
Mars is really far away!
The distance between Earth and Mars is constantly changing as they travel around the sun. The closest approach in recent history was in 2003, when they were about 35 million miles apart. At their farthest point, Earth and Mars are separated by 250 million miles.
Timing is everything. About every two years, Mars and Earth reach a minimum distance, making travel between the planets more manageable.
However, using conventional chemical propulsion, the voyage can take almost a year, assuming that we leave Earth when Mars is closest, and depending on how much fuel is available. If we plan on returning to Earth, we will need to wait until Mars and Earth are back in alignment. An end to end human mission to Mars could take 3 years!
Going to Mars will be very dangerous!
“Space is dangerous. It’s what we do here. If you want to play it safe all the time, go join an insurance company.”
― Andy Weir, The Martian
In order to setup a colony on Mars, mission planners and engineers need to figure out how to address some basics. Water, Air, Food and Shelter are high priorities. However, power is also critical as all of the above will rely on a reliable power source. They will also have to figure out how to deal with some significant risks.
Water and Air
There isn’t a lot of water here on Mars. There’s ice at the poles, but they’re too far away. If I want water, I’ll have to make it from scratch. Fortunately, I know the recipe: Take hydrogen. Add oxygen. Burn.”
― Andy Weir, The Martian
Water is the key to life. With a reliable source of water, it will be possible to irrigate gardens, produce breathable air, and even make hydrogen and oxygen propellants so that colonists can return to Earth if they need to— but it is not feasible to bring the water our colonists will need from Earth. So, to sustain a permanent colony, it will be necessary to use local sources of water. Fortunately, there is a great deal of water on Mars(!). Unfortunately, it is not easy to get to. Water ice is known to form at the poles, and in craters. There is water in the ground, and the Martian soil has trace amounts of water as well.
Mark Watney was unable to travel to the Martian poles, was not near an icy crater, and could not find underground deposits of ice. He was forced to made water from the chemical propellants he had available. It was a great chemistry lesson, but definitely not an experiment to try at home. And carrying propellants to Mars to make water is even worse than trying to carry the water itself.
Establishing our colony close to a known source of water, is the best solution. In the National Geographic series “Mars”, colonists found a cave full of ice. While that would be a fantastic find, it is probably not wise to plan on finding such a treasure soon after landing. Technology exists to extract water from the soil and Oxygen from the thin CO2 atmosphere. Improving the reliability of these processes is critical to settling people on Mars.
So, the trifecta for securing adequate water and air for our colony on Mars will be: 1) Try to locate the colony near an ice source, 2) extract water from the soil, and 3) Extract oxygen from the atmosphere and local water. We need to pursue all three if we want our colony to succeed. Redundancy is a huge confidence builder when your life is on the line.
“..have I mentioned I’m sick of potatoes? Because, by God, I am sick of potatoes. If I ever return to Earth, I’m going to buy a nice little home in Western Australia. Because Western Australia is on the opposite side of Earth from Idaho.”
― Andy Weir, The Martian
Keeping people alive healthy on Mars will require a varied diet. In order to produce the full range of nutrients and vitamins needed, our colony will have to establish a large and varied botanical garden.
This will be a non trivial undertaking as there is no way to demonstrate conclusively how well Earth plants grow in Martian soil. And it is not very practical to send the colonists with tons of Earth dirt (is that redundant?)…. The good news is that researchers are optimistic based on what they know about Martian soil chemistry. Even better, it is thought that that hops will grow well in Martian soil(!). Establishing a local beer supply will be key to the happiness and contentment of colonists.
Building a large scale agricultural production will require time, experimentation, and equipment in addition to seeds, water, lights, and soil modifiers. And providing colonists with a varied diet will be critical to maintaining mental and emotional health.
The colony will initially have to rely on supplies form Earth, but if it is to last, steady progress will have to be made in expanding the food supply.
“Problem is (follow me closely here, the science is pretty complicated), if I cut a hole in the Hab, the air won’t stay inside anymore.”
― Andy Weir, The Martian
Building our colonists a place to live means contending with surface conditions that include very low atmospheric pressure, almost no oxygen, extreme cold, low pressure, and high radiation.
Bringing inflatable habitations from Earth is feasible, but these will not provide the durability and radiation protection needed for long term living.
Further, every pound used to carry habitat materials to Mars is a pound that cannot be used to carry something else. And given the fact that the cost per pound of materials transported to Mars is likely to be hundreds of thousands of dollars —if not more. It doesn’t make sense to take things that can be manufactured in place.
Habitats can be placed underground, for example in lava tubes that are known to exist on Mars, or placed above ground and covered with martian regolith (soil) to protect colonists from radiation exposure. Scientists and architects are working to understand how to make use of in-situ materials combined with materials brought from Earth, and construction techniques such as 3D printing. It is even thought that with some added Earth based fillers, Martian bricks could be used to build homes.
Another challenge is picking the right location for settlement in advance, since once on the ground colonists will not be able to easily relocate their base of operations. Identifying a site that is close to ice, building materials, and geological features needed to shield the habitat will be a challenge and drive the need for advance missions to find suitable locations.
“With no magnetic field, Mars has no defense against harsh solar radiation. If I were exposed to it, I’d get so much cancer, the cancer would have cancer.”
― Andy Weir, The Martian
Beyond Low Earth Orbit, our colonists will have significant risk for radiation sickness, and an increased lifetime risk for central nervous system damage, cancer, and degenerative diseases.
The radiation that colonists will see on the surface of Mars, will also be much higher that that of Earth.
Advance missions and studies are needed to better quantify the radiation environment, but it is clear that shielding during the trip to and from Mars as well as shielding of Martian habitats, and limitations on surface travel may be required to prevent colonists from severe illness and early death.
Some visionaries foresee terra-forming Mars so that humans can live outside without pressure suits. However, Mars lacks a magnetic field such as we have on Earth, so radiation protection will always be an issue — even if we can kick start a martian atmosphere.
“If the oxygenator breaks down, I’ll suffocate. If the water reclaimer breaks down, I’ll die of thirst. If the Hab breaches, I’ll just kind of explode. If none of those things happen, I’ll eventually run out of food and starve to death. So yeah. I’m fucked.”
― Andy Weir, The Martian
Keeping things running on Mars will be tough. Electronics do NOT like the space radiation environment. They also don’t like temperature extremes or vacuum. And bumpy rides such as they will experience on the ascent into Earth orbit and landing on Mars are not fantastic for them either.
Today, we use special space rated parts in hermetically sealed boxes. When a box fails — we replace it. That is not the best approach for a Mars colony. We cant bring enough replacement boxes, and it is a long way back to Earth if our colonists run short on spares.
To make matters worse, some have suggested that we send equipment, power systems, habitats, and supplies to Mars in advance of the explorers so they don’t have to carry everything with them. The idea is that once everything is on the ground, and we verify that it is working — it will be safe to send the astronauts in a smaller spacecraft. This means that the hardware will have to operate for years without failure — and perhaps a couple of years before colonists even arrive.
Simpler, repairable, redundant, and rugged equipment will be needed for our Mars colony — not bleeding edge technology. But it seems clear that resupply from Earth will be needed for a long time as the colony builds infrastructure, sources local materials and builds a large and diverse production base to produce its own equipment and spare parts.
“…engineers typically describe landing on Mars as “7 minutes of terror.” “
Landing on Mars is still hard, Deborah Byrd in SPACE | November 25, 2018
Another significant issue that needs to be addressed before we send large numbers of people to Mars is entry, descent and landing (EDL). The thin atmosphere makes landing our colonists and their supplies on the surface difficult. We know how to land in a dense atmosphere like Earth, or in a vacuum like the Moon. Mars has just enough atmosphere to make this more more difficult than either.
Our experience to date has been with much smaller spacecraft. Figuring out how to safety land our larger spacecraft will be challenging. And advance missions to demonstrate these technologies are needed.
There is no shortage of people that want to go to Mars. NASA certainly wants to send a manned mission, but given the way that NASA programs and politics work, that is likely decades and tens of billions of dollars in the future.
The Mars One program planned to send colonists volunteers to Mars in the 2020s to establish a permanent colony — but went bankrupt earlier this year.
Elon Musk has promised human missions to Mars in the mid 2020s with colonization to follow. SpaceX is developing a large capacity rocket that it intends to use for the Mars initiative. However, as I illustrated above, there is much more to do if we intend to colonize Mars than build a rocket to send people there.
The thing about planetary exploration that is hard for politicians and citizens alike to support is that to do it “right” you need to spend twice as much. However if you do that you will get a 10X improvement in mission success and and reduce the chance of death by a factor of ten too. I made up these numbers, but my own experience in NASA programs for over 35 years tells me that this is essentially true. Done the conventional way, sending people straight there, I would not be surprised to see a 20% or higher probability of catastrophe and death.
Technology Demonstration and Survey Missions
“Ever set up a camping tent? From the inside? While wearing a suit of armor? It was a pain in the ass.”
― Andy Weir, The Martian
Virtually everything we want to do on Mars is much harder than here on Earth. We need to take steps to figure out how to do things efficiently and effectively before we send our colonists there.
Go back to the Moon
Using the moon as a test bed for Mars mission technologies can significantly reduce the risks of going straight there. While the moon is not an identical environment, many of the technologies needed to support Mars colonists can be tested. The production of water, hydrogen and oxygen on the lunar surface would also reduce the need to carry these up from Earths steep gravity well on expensive disposable rockets.
Keep sending robots, and conduct short human missions
Robotics missions and short term human explorations can be used to fill in the gaps in our information, find a good site for permanent settlement, and start building up infrastructure for a colony to include stockpiling Martian produced water.
The key here is having a logical campaign versus a single triumphant (or disastrous) event.
The propulsion technologies NASA and SpaceX use today are essentially the same as those used by Apollo. Nuclear thermal propulsion systems such as the NERVA program (demonstrated decades ago) can triple the efficiency of propulsion and cut the journey time in half. This means less volume and mass dedicated to simply getting there, as well as more flexibility in planning missions.
Research should be conducted to evolve current space systems for avionics, life support, thermal control, power, and others so that we have more rugged, reliable, and repairable systems. Again, testing these out on the Moon will increase confidence and reliability.
Build an interplanetary logistics base
While the Moon could become a logistics based for interplanetary exploration, it has also been proposed that we use the Martian Moon Phobos as a logistical base.
Phobos which is a 7 mile wide irregularly shaped body believed to contain a great deal of ice. Phobos could serve as a filling station for spacecraft coming and going from Mars. It could also serve as a base to stockpile supplies using transfer ships that do not have to be designed to land on Mars.
Share the cost
Sharing the cost between government, commercial and private investors is becoming more common — as is international mission collaboration. However, these efforts are frequently mired down in politics and take much longer to accomplish at much higher cost. We need to break the code on politics so that such ventures can be efficient. Without a doubt, collaboration could be a huge force multiplier in making a Mars colony happen.
A different breed of colonists
In order to be successful, our colony will need fewer hot shot pilots and more botanists, engineers, doctors, and chemists. Today’s astronaut core has evolved since Apollo days, but is still dominated by pilots. We need our colonists to have a bit of Macgyver in them so that they can adapt, and make do with less.
So let’s go to Mars! But let’s do it the right way and give our colonists a fighting chance.