Colonization of Mars facts for kids

The settlement of Mars is the idea of building permanent homes for humans on the planet Mars. Most plans focus on creating places where people can live. However, the word "colonization" has a broader meaning, which international space law has limited. Instead, space programs often talk about sending humans to Mars for exploring the planet. To settle Mars, humans would need to travel there, set up a lasting presence, and use the planet's own resources.

No human missions have reached Mars yet, but many robotic missions have been successful. Space agencies like NASA, ESA, and SpaceX have explored ideas for settling Mars. They mostly focus on more robotic exploration and the chance of human landings. Groups like the Mars Society and private companies like SpaceX support the idea of settling Mars. The dream of living on Mars has also been explored a lot in science fiction books, movies, and art.

Some big challenges to settling Mars include strong ionizing radiation and fine, toxic dust. Mars has an atmosphere, but it's too thin to breathe. Temperatures change a lot, from about -70°C to 0°C. Mars has underground water and other resources. But it's hard to make power using wind or solar energy there. Also, there are not many resources for nuclear power. Mars's orbit is the third closest to Earth's, but the distance is still a big problem for moving supplies and people.

People want to settle Mars for many reasons. These include learning new things, doing deep research, and making sure humans survive if something bad happens on Earth. They also want to create a new society independent from Earth and use Mars's resources.

Learning About Mars Settlement

What Does "Settlement" Mean?

The idea of settling Mars is different from just sending humans to explore it. Exploration missions aim to land people for a short time to learn.

The words we use for humans living in space have been thought about a lot. Some experts, like Carl Sagan, preferred "settlements" or "cities" instead of "colonies." This is because "colonies" can remind people of colonialism, which has a negative history. Today, "settlement" is often preferred for similar reasons.

However, some people, like Robert Zubrin and the SpaceX Mars colonization program, still use "colonization." They even use the phrase Occupy Mars. They dream of an independent Mars colony, even with current space law limits.

Early Ideas for Missions

Robotic rovers have successfully explored Mars and sent back information. The first successful lander, Viking 1, landed in 1976.

Many ideas for human missions to Mars have been suggested. But no person has traveled there yet, and no return missions have happened. Most current plans from government space programs are just for exploration. They don't aim to build a permanent base right away. To truly settle Mars, permanent homes are needed that can grow and support themselves. Early ideas for building homes on Mars include the Mars Direct and Semi-Direct plans, suggested by Robert Zubrin.

In 2017, the United Arab Emirates announced a plan to build a settlement on Mars by 2117. This project is led by the Mohammed bin Rashid Space Centre.

Mars Compared to Earth

Atmospheric pressure comparison

Place	Pressure
Olympus Mons top	72 Pa (0.0104 psi) (very low)
Mars average	610 Pa (0.088 psi) (very low)
Hellas Planitia bottom	1.16 kPa (0.168 psi) (low)
Armstrong limit	6.25 kPa (0.906 psi) (point where body fluids boil)
Mount Everest top	33.7 kPa (4.89 psi) (low on Earth)
Earth sea level	101.3 kPa (14.69 psi) (normal Earth pressure)

Gravity and Size

The gravity of Mars is only 38% of Earth's. This means you would feel much lighter there. We don't know if this lower gravity would cause health problems like muscle and bone loss, which happens in zero gravity. A project called the Mars Gravity Biosatellite was planned to study this, but it didn't get enough money.

Mars has a surface area that is about 28.4% of Earth's. This is almost the same as the amount of dry land on Earth. Mars is half the size of Earth and has only one-tenth of its mass. This means it has a smaller volume and is less dense than Earth.

No Strong Magnetic Field

Mars does not have a strong magnetosphere (a protective magnetic field like Earth's). Because of this, harmful solar particle events and cosmic rays can easily reach the Martian surface.

Thin Atmosphere

The Atmospheric pressure on Mars is very low. It's far below the Armstrong limit, which is the pressure needed for humans to survive without pressure suits. Since changing Mars's atmosphere (terraforming) isn't a short-term solution, homes on Mars would need to be like pressure vessels. These would keep the air pressure safe for humans.

The atmosphere is also toxic because it's mostly carbon dioxide (95%). It has very little oxygen (less than 0.4%). This thin air also means that ultraviolet sunlight is not filtered out. This can break down molecules like ammonia. Also, because the atmosphere is so thin, temperatures change a lot between day and night, usually by about 70°C.

Water and Climate

Water on Mars is rare. Rovers like Spirit and Opportunity found less water than in Earth's driest deserts.

The climate is much colder than Earth's. Average surface temperatures are between -87°C and -5°C. The coldest temperature ever recorded on Earth was -89.2°C in Antarctica.

Mars is about 52% farther from the Sun than Earth. So, it gets less sunlight. However, because its atmosphere is so thin, more of that sunlight reaches the surface. Sunlight on Mars is like a moderately cloudy day on Earth. Mars's orbit is more oval-shaped than Earth's, which causes bigger temperature changes throughout the Martian year. Mars has no rain and almost no clouds, so it's usually sunny, except during dust storms. This means solar panels can work very well on clear days.

Global dust storms are common. They can cover the whole planet for weeks, blocking sunlight. This has caused temperatures to drop by 4°C for several months. These dust storms would affect solar power production for long periods and make communication with Earth difficult.

Temperature and Seasons

Mars has a tilt of 25.19 degrees, similar to Earth's 23.44 degrees. Because of this, Mars has seasons just like Earth. But they last almost twice as long because a Martian year is about 1.88 Earth years. Mars's temperatures are more like Earth's than any other planet's in the Solar System. While generally colder, Mars can have Earth-like temperatures in some places and at certain times.

Toxic Soil

The soil on Mars is toxic. It has high levels of chlorine and chemicals like perchlorates. These are harmful to all known life forms. Some tiny organisms on Earth can handle high perchlorate levels, but it's still a big problem for humans.

Can Life Survive?

Plants and animals cannot survive naturally on the surface of Mars. However, some extremophile organisms (which live in harsh conditions on Earth) have survived in environments that are similar to Mars.

Length of Day

A Martian day, called a sol, is very similar to an Earth day. It lasts 24 hours, 39 minutes, and 35.244 seconds.

Living Conditions for Humans

Conditions on Mars are closer to Earth's in terms of temperature and sunlight than any other planet or moon. The only exception is the cloud tops of Venus. However, the surface of Mars is not good for humans or most known life forms. This is because of radiation, very low air pressure, and an atmosphere with only 0.16% oxygen.

In 2012, scientists reported that some lichen and cyanobacteria survived and adapted well to photosynthesis after 34 days in experiments that partly copied Martian conditions. These experiments were done in the Mars Simulation Laboratory (MSL) in Germany. Some scientists think cyanobacteria could help create self-sustaining human outposts on Mars. They could be used to make food, fuel, and oxygen.

Humans have explored parts of Earth that are similar to Mars. Temperatures on Mars (in warmer areas) are like those in Antarctica. The air pressure at the highest altitudes reached by piloted balloons (35-38 km high) is similar to Mars's surface. However, the pilots were in pressurized capsules, not exposed to the low pressure.

For humans to survive on Mars, they would need to live in artificial Mars habitats with complex life-support systems. Water recycling would be very important. Humans are mostly water and would die in days without it. On Earth, a person uses a lot of water daily. Astronauts on the International Space Station (ISS) use much less and recycle about 70% of their water. Similar, but even more efficient, systems would be needed on Mars. Getting water from Earth would be too expensive. NASA has looked into finding water on Mars by drilling.

How Mars Affects Human Health

Mars is a difficult place for humans to live. New technologies are being developed for long space travel that could help with living on Mars. The longest time a person has spent in space continuously is 438 days (by Valeri Polyakov). The most total time in space is 1,111 days (by Oleg Kononenko). The longest time spent outside Earth's protective Van Allen radiation belt was about 12 days during the Apollo 17 Moon landing. This is short compared to the 1100-day trip to Mars and back that NASA is thinking about for 2028. Scientists also think that many body functions could be harmed by the Mars environment. High radiation levels cause physical side effects that need to be managed. Also, Martian soil has high levels of toxins that are bad for human health.

Physical Changes

The different gravity on Mars might harm human health by making bones and muscles weaker. There's also a risk of osteoporosis (weak bones) and heart and blood vessel problems. Astronauts on the International Space Station (ISS) live in zero gravity for six months. This is about the same time as a one-way trip to Mars. This helps researchers understand how astronauts might feel when they arrive on Mars. Once on Mars, the gravity is only 38% of Earth's.

Microgravity affects the heart, muscles, bones, and brain. For example, on Earth, blood stays mostly below the heart. In microgravity, there's nothing pulling the blood down. This can cause problems. Astronauts often have puffy faces and thin legs. After returning to Earth, they can lose a lot of blood plasma. Long space flights also cause bones to lose minerals and muscles to shrink. When astronauts return, they can feel dizzy, sick, and disoriented. These health effects would be a serious concern on Mars. Recovering from bone and muscle loss can take a long time, and some effects might never fully go away.

Radiation Danger

Even though Mars is farther from the Sun than Earth, dangerous amounts of radiation reach its surface. Mars lost its inner dynamo, so it has a weaker global magnetosphere than Earth. This, combined with a thin atmosphere, allows a lot of ionizing radiation to reach the surface.

There are two main types of radiation risks: galactic cosmic rays (GCR) and solar energetic particles (SEP). Earth's magnetic field protects us from charged particles from the Sun. Our atmosphere protects us from GCRs. We can reduce solar radiation, but for GCRs, the only solution is heavy shielding. This would mean about 15 centimeters of steel, 1 meter of rock, or 3 meters of water. This means human settlers would need to live underground most of the time.

The Mars Odyssey spacecraft has an instrument called MARIE to measure radiation. MARIE found that radiation levels in orbit above Mars are 2.5 times higher than on the International Space Station. This is much higher than the total radiation from thousands of nuclear weapon tests. The average daily dose was about 0.08 Gy per year. Three years of this level would be more than NASA's safety limits. The risk of getting cancer from radiation after a Mars mission could be twice what scientists thought. Sometimes, solar proton events (SPEs) cause much higher doses. In September 2017, radiation levels on Mars's surface temporarily doubled due to a huge solar storm. Building homes underground, possibly in Martian lava tubes, would greatly reduce radiation exposure.

Much is still unknown about space radiation. In 2003, NASA opened a facility to simulate space radiation and study its effects on living things. They also test shielding methods. Early on, some thought low-level radiation might not be as dangerous. But a 2006 study showed that protons from cosmic radiation might damage DNA twice as much as thought. This means astronauts face a higher risk of cancer and other diseases. Because of the high radiation on Mars, a 2009 report said that "Mars is not an easy place to visit with existing technology." NASA is looking into new ways to protect astronauts and spacecraft, like deflector shields made of plasma.

Mental Effects

Because of communication delays, new ways are needed to check on astronauts' mental health. Researchers have created a Mars simulation called HI-SEAS in Hawaii. Scientists live in a simulated Mars lab to study the mental effects of being isolated, doing the same tasks, and living in close quarters for up to a year. Computer programs are being made to help crews with personal problems when they can't talk directly to experts on Earth.

Changing Mars to Be Like Earth (Terraforming)

Terraforming Mars means trying to change the planet so that Earth life could survive there without special protection. Ideas for terraforming of Mars have been suggested, but there's a lot of debate about if it's possible and if it's right to do.

How Many People Are Needed for a Colony?

There's no clear answer on the smallest number of people needed for a colony to survive without problems like inbreeding. One study suggested at least 110 people for a Mars colony. Other studies for interstellar settlements suggest numbers from 198 to 10,000.

To be self-sustaining, a colony would need to be big enough to provide all necessary services. These include:

• Managing the environment: making gases, controlling air, collecting water, growing food, and processing waste.
• Making energy: like getting methane for vehicles or processing materials for solar panels.
• Industry: getting and processing ores, making tools, clothes, medicine, glass, and plastics.
• Building: creating and fixing structures as the settlement grows.
• Social life: raising and educating children, health care, cooking, cleaning, and making decisions. Time for sports and fun is also important.

Getting to Mars

Space Travel Between Planets

Mars needs less energy to reach from Earth than any planet except Venus. Using a simple path called a Hohmann transfer orbit, a trip to Mars takes about nine months. Faster paths are possible, taking four to seven months, but they need more fuel. Going faster than six months is hard with regular chemical rockets. It might be possible with advanced technologies like Variable Specific Impulse Magnetoplasma Rocket or nuclear rockets. With these, a trip could be as short as two weeks. In 2016, a scientist suggested a tiny robotic probe could reach Mars in "as little as 72 hours" using a laser-powered sail.

During the journey, astronauts would face radiation, so they would need protection. Cosmic radiation and solar wind can damage DNA, increasing the risk of cancer. The long-term effects of space travel are unknown. Scientists estimate an added cancer risk of 1% to 19% for males on a round trip to Mars. For females, the risk is higher due to more glandular tissues.

Landing on Mars

Mars has gravity that is 0.38 times Earth's. Its atmosphere is very thin, about 0.6% of Earth's. The gravity is strong enough, and there are some air effects, but the atmosphere is too thin to help much with slowing down a large spacecraft. Landing human missions on Mars would need new braking and landing systems. These would be different from what was used for Moon landings or robotic Mars missions.

If super-strong materials like carbon nanotubes become available, a space elevator could be built to land people and supplies on Mars. A space elevator on Phobos, one of Mars's moons, has also been suggested.

Phobos as a Space Elevator for Mars

Phobos orbits Mars in a special way, always showing the same side to the planet. It's about 6,028 kilometers above the Martian surface. A space elevator could stretch down from Phobos to Mars, reaching about 28 kilometers above the surface, just outside the atmosphere of Mars. Another cable could extend 6,000 km in the opposite direction to balance Phobos. In total, the elevator would be over 12,000 km long.

A rocket launch would still be needed to get to the bottom of the space elevator, 28 km above the surface. The surface of Mars rotates at 0.25 km/s at the equator, and the bottom of the elevator would rotate at 0.77 km/s. So, only a small speed change would be needed to reach the elevator. Phobos orbits at 2.15 km/s, and the outer part of the elevator would rotate at 3.52 km/s.

What Equipment is Needed for a Colony?

Settling Mars would need a lot of equipment. This includes things for people to live comfortably and machines to make food, fuel, water, energy, and oxygen. Key equipment would be:

• Basic utilities like oxygen, power, local communication, waste disposal, and water recycling.
• Homes for people.
• Storage areas.
• Workspaces.
• Airlocks for entering and exiting, and for managing dust.
• Equipment to get resources from Mars. At first, this would be for water and oxygen. Later, it would be for minerals and building materials.
• Equipment for energy production and energy storage, like solar panels and maybe nuclear power.

• Areas and equipment for growing food.
• Equipment to make rocket fuel. This would likely be hydrogen and methane for fuel, with oxygen as an oxidizer.
• Fuels or energy sources for surface transportation. Methanol or carbon monoxide/oxygen engines have been suggested. These can be made from the Martian atmosphere without using Mars's water.
• Equipment for communicating with Earth.
• Equipment for moving around on the surface, like space suits, crewed rovers, and possibly Mars aircraft.

Basic Services

For the colony to work, it would need basic services like power, water, and communications. These systems would need to be built to handle the harsh Mars environment. They would either need to be fixed while wearing a space suit or be inside a human-friendly area. For example, if the colony uses solar power, it would need large energy storage for when dust storms block the sun. Automatic dust removal systems might also be needed. If the colony grows beyond a few people, systems would need to use Mars's local resources as much as possible. This would reduce the need for supplies from Earth. For example, recycling water and oxygen, and using any water found on Mars.

Talking to Earth

Communicating with Earth is fairly easy when Earth is visible from Mars. NASA and ESA have put communication equipment on several Mars orbiters. So, Mars already has communications satellites. While these will eventually wear out, more will likely be launched before any human missions.

The time it takes for a message to travel one way (due to the speed of light) is about 3 minutes when Earth and Mars are closest. It can be up to 22 minutes when they are farthest apart. This long delay makes real-time conversations, like phone calls, very hard. NASA has found that direct communication can be blocked for about two weeks when the Sun is directly between Mars and Earth. This is called superior conjunction.

A satellite at the L₄ or L₅ Earth–Sun Lagrangian point could help with communication during this time. Even a group of communication satellites would be a small cost for a full colonization program. However, the size and power needed for equipment at these distances make L4 and L5 locations difficult. Also, these stable regions can attract dust and asteroids, which could be a risk. Still, the STEREO probes passed through these regions without damage in 2009.

Recent work by the University of Strathclyde and the European Space Agency suggests another way to communicate. They propose using special orbits that allow a relay spacecraft to "hover" above Mars, out of the planets' orbital plane. This would allow continuous communication during solar conjunction.

Robots Paving the Way

Robotic systems like the Mars Exploration Rovers Spirit, Opportunity, Curiosity, and Perseverance could prepare the way for a human colony. These robots could find resources like groundwater or ice, which would help a colony grow. These systems can last for years or even decades. As seen in commercial spaceflight, private companies might also own some of these systems. Robotic missions also cost less and have fewer political risks than early human missions.

Robots could set up the basics for early human landings and bases. They could produce things like fuel, oxygen, water, and building materials. Setting up power, communications, shelter, heating, and basic manufacturing can start with robots before humans arrive.

The Mars Surveyor 2001 Lander MIP (Mars ISPP Precursor) was planned to show how to make oxygen from the atmosphere of Mars. It would also test solar cell technologies and ways to deal with Martian dust on power systems.

Before people travel to Mars on the future SpaceX transportation system, many robotic cargo missions would go first. These would carry necessary equipment, habitats, and supplies. This equipment would include "machines to produce fertilizer, methane and oxygen from Mars' atmospheric nitrogen and carbon dioxide and the planet's subsurface water ice." It would also include building materials for transparent domes for early farming areas.

Stages of Settlement

Experts have described different stages for settling Mars:

1. Pre-settlement: A small outpost (in the near future).
2. In-settlement: A permanent settlement (in the medium future).
3. Post-settlement: A society that can support itself (in the long future).

Money and Mars

Making Space Travel Cheaper

The rise of reusable rockets in the 2020s has greatly lowered the cost of getting into space. SpaceX Falcon 9 rockets, for example, are very affordable. SpaceX has successfully developed reusable technology with Falcon 9 and Falcon Heavy. They are also working fast on making their Starship reusable. This is expected to "greatly impact the cost of space travel" and make the space launch market more competitive.

Another way to fund space colonization could be through prizes. For example, a 2004 US commission suggested offering a prize to the first group to put humans on the Moon and keep them there for a set time before they return.

Using Mars's Resources and Trading with Earth

So far, there's no clear proof of many valuable resources on Mars that Earth would want. The huge distance between Mars and Earth would make trading between the planets very difficult.

Local Trade on Mars

Some early Mars colonies might focus on using local resources for their own needs, like water or ice. Local resources can also be used to build things. One source of Martian ore known to be available is metallic iron from nickel–iron meteorites. This iron is easier to get than iron from the iron oxides that cover the planet.

Another thing that could be traded between different parts of a Mars colony is manure. This is because Mars soil is very poor for growing plants.

Solar power is a good option for a Mars colony's energy. Mars gets about 42% of the sunlight Earth does. But because Mars's atmosphere is so thin, almost all that energy reaches the surface. This is unlike Earth, where the atmosphere blocks about a quarter of the sunlight.

Mining Asteroids from Mars

Since Mars is much closer to the asteroid belt than Earth, it would take less energy to get to the Asteroid belt and bring minerals back to Mars. Some think that the Moons of Mars (Phobos and Deimos) might actually be asteroids caught by Mars's gravity.

The asteroid 16 Psyche in the main belt could have minerals worth over 10,000 quadrillion dollars. NASA launched the Psyche orbiter in 2023, which is set to reach the asteroid by 2029.

511 Davida could have $27 quadrillion worth of minerals. Using the moon Phobos to launch spacecraft is good for energy and a useful place to send missions to main belt asteroids.

Mining the asteroid belt from Mars and its moons could help a lot with settling Mars.

Where to Settle on Mars

The Poles

Some have suggested setting up the first base at a Martian pole. This would give easy access to water.

Caves

Caves would naturally protect humans from dangers on Mars. These dangers include radiation, impacts from space rocks, and the big temperature changes on the surface.

Mars Odyssey found what look like natural caves near the volcano Arsia Mons. People think settlers could use these or similar structures for shelter from radiation and tiny meteoroids. Geothermal energy (heat from inside the planet) is also thought to be present in areas near the equator.

A team of researchers found about 139 caves that are worth exploring as possible shelters. Each was within 60 miles (96 km) of a good landing site and had been photographed in high detail.

Lava Tubes

Several possible Martian lava tube entrances have been found on the sides of Arsia Mons. On Earth, these tubes can have long passages that offer full protection from radiation. They would also be fairly easy to seal using materials found on Mars, especially in smaller parts.

Hellas Planitia

Hellas Planitia is the lowest plain on Mars. The air pressure there is higher than in most other places on Mars.

How Humans Might Change Mars

There has been a lot of discussion about how humans on Mars would affect any possible native life there. More deeply, people have talked about how we understand human life compared to alien life, and their different values.

Protecting the Planet

Robotic spacecraft sent to Mars must be cleaned very well. They can have at most 300,000 tiny living things (spores) on their outside. They must be cleaned even more if they touch "special regions" with water. Otherwise, there's a risk of contaminating experiments or even the planet itself.

It's impossible to clean human missions to this level. Humans carry trillions of microorganisms of thousands of types, and these cannot be removed without harming the person. Keeping them contained seems to be the only option, but this is a big challenge if there's a hard landing (a crash). There have been workshops on this topic, but no final rules have been set. Human explorers could also bring Martian microorganisms back to Earth if Mars has life.

Rules and Politics

The 1967 United Nations Outer Space Treaty states that no country can claim space or its inhabitants. Many parts of this treaty prevent the legal colonization of outer space.

NASA has faced several budget cuts. During Barack Obama's presidency, the goal for NASA to reach Mars was less emphasized. In 2017, President Donald Trump promised to send humans back to the Moon and eventually Mars. He increased NASA's budget by $1.1 billion, mostly for developing the new Space Launch System.

It's not clear how the first human landing on Mars will change current rules about space exploration and living on other planets. Since Mars is a very challenging and dangerous place for humans, the laws and culture there will likely be different from Earth's. With Elon Musk announcing his plans for Mars travel, it's uncertain how a private company possibly being the first to put a human on Mars will affect things globally.

Thinking About Right and Wrong

Some argue that settling Mars might take attention away from solving problems on Earth. They say that plans for Mars are often about our plans for Earth. Jeff Bezos, who founded Blue Origin (a competitor to SpaceX), has called Mars colonization a "Plan B." He suggests we should protect Earth by developing space and moving all heavy industry into space.

It has been pointed out that the impact of human settlement on Mars, especially regarding planetary protection, hasn't been fully answered.

Some argue that there are physical and social problems that need to be solved for long-term survival on Mars. Former President Barack Obama said Mars would be more unwelcoming than Earth "even after a nuclear war." Others point out that Earth and underground shelters on Earth could still offer better conditions and protection from terrible events. Lord Martin Rees, a British scientist, has called Mars colonization a 'dangerous delusion.' Elon Musk has said that staying on Mars is life-threatening and needs to be "glorious" to be worth it. Some also argue that robotic missions are better for exploring Mars because human missions are too expensive, dangerous, and boring.

Colonialism Concerns

Space colonization has been seen by some as a continuation of imperialism and colonialism. Especially regarding Mars, questions have been raised about how decisions would be made, why people would work there, and how land would be used. Many people call for fair and democratic ways to explore and settle space to prevent racism, sexism, and other unfairness.

The idea of space exploration as a "New Frontier" has been criticized. Some say it's an unthinking continuation of settler colonialism and manifest destiny, suggesting that exploring new lands is just part of human nature.

The main way people think about claiming territory in space is called surfacism. This compares supporting the colonization of Mars to opposing the colonization of Venus.

Dangers During Pregnancy

One ethical challenge for space travelers is pregnancy during a trip. A pregnant person on a spacecraft would create more risks for herself and everyone else. The pregnant person and child would need extra food and special care. The pregnancy would also affect the crew member's duties. We don't fully know how the space environment would affect a child's development. However, a fetus would be more sensitive to solar radiation in space, which would likely harm its cells and genes.

Who Supports Mars Settlement?

Several non-government groups support Mars colonization for different reasons. One of the oldest is the Mars Society. They promote a NASA program for human exploration of Mars and have set up Mars-like research stations. Mars to Stay supporters want to turn emergency return vehicles into permanent homes once explorers decide it's possible to live there.

Elon Musk started SpaceX with the long-term goal of developing technology for a self-sustaining human colony on Mars. Richard Branson hopes to help start a population on Mars in his lifetime. He believes it's "absolutely realistic" and will happen. He thinks that over the next 20 years (from 2012), they will take hundreds of thousands of people to space, which will provide money for bigger things.

Author Robert Zubrin has strongly supported Mars exploration and colonization for many years. He is part of the Mars Society and has written several books about it, both fiction and non-fiction. In 1996, he wrote The Case for Mars: The Plan to Settle the Red Planet and Why We Must. He continues to support Mars and space exploration.

In 2013, Buzz Aldrin, the second person to walk on the Moon, wrote an article supporting a human mission to Mars. He saw the Moon "not as a destination but more a point of departure" to settle Mars and become a "two-planet species." In 2015, Aldrin presented a "master plan" for NASA. It suggested astronauts with a "tour of duty of ten years" could colonize Mars before 2040.

There are also critics of Mars colonization. American political scientist Daniel Deudney argues that a fully developed Mars colony could be a danger to humans remaining on Earth. His book, Dark Skies, challenges the idea that a Mars colony would be friendly to Earth. He says this is an assumption, and a future Mars colony might have its own goals and desires, different from Earth's.

Mars in Stories

Many fictional stories describe Mars colonization in detail. Some examples include:

• Aria (2002–2008), a Japanese comic series
• Away (2020), a TV show on Netflix
• Climbing Olympus (1994), by Kevin J. Anderson
• First Landing (2002), by Robert Zubrin
• For All Mankind (2019), a TV show on Apple TV+, from Season 3 onwards
• Icehenge (1985), the Mars trilogy (Red Mars, Green Mars, Blue Mars, 1992–1996), and The Martians (1999), all by Kim Stanley Robinson
• John Carter (2012), a movie
• Man Plus (1976), by Frederik Pohl
• The Martian (1992) and Return to Mars (1999), by Ben Bova
• Mars (2016), a TV series by National Geographic
• Mars Diaries (2000), by Sigmund Brouwer
• Mars Underground (1997), by William K. Hartmann
• Martian Gothic: Unification (2000), a video game
• Mr. Nobody (2009), a movie
• Red Faction (2001), a video game
• Red Planet (1949), by Robert A. Heinlein
• Surviving Mars (2018), a video game
• Terra Formars (2011), a Japanese comic series
• TerraGenesis (2016), a video game
• The Expanse (2016–2021), a TV series
• The Martian (2011), by Andy Weir (and the 2015 film)
• The Martian Chronicles (1950), by Ray Bradbury
• The Sands of Mars (1951), by Arthur C. Clarke
• The Space Between Us (2016 film)
• Tom and Jerry: Blast Off to Mars (2005), an animated movie
• Total Recall (1990), a movie
• We Can Remember It for You Wholesale (1966), by Philip K. Dick

See also