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Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.
Is it possible that we could make Mars like Earth one day? – Tyla, age 16, Mississippi
When I was in middle school, my biology teacher showed the sci-fi movie “Star Trek III: The Search for Spock” to our class.
The plot drew me in, with its portrayal of the “Genesis Project” – a new technology that transformed a dead alien world into one teeming with life.
After watching the film, my teacher asked us to write an essay about that technology. Was it realistic? Was it ethical? And channeling our inner Spock: Was it logical? This assignment really impressed me.
Fast forward to today, and I am an engineer and professor developing technologies to extend human presence over Earth.
For example: I am working on advanced propulsion systems to take spacecraft beyond Earth orbit. I am helping to develop lunar construction technologies to support NASA’s goal of a long-term human presence on the Moon. And I was on a team that showed how to 3D print habitats on Mars.
It will take a lot of time, energy and imagination to sustain humans off Earth. But engineers and scientists have risen to the many challenges.
Partial checklist: Food, water, shelter, air
After the Moon, Mars is the next logical place for humans to live outside of Earth.
But can Mars be mapped – that is, changed to resemble Earth and support life? Or is that just the stuff of science fiction?
Life on Mars will require liquid water, food, shelter and an atmosphere with enough oxygen to breathe and thick enough to retain heat and protect against radiation from the Sun.
But the Martian atmosphere is almost all carbon dioxide, with almost no oxygen. And it’s very thin – only about 1% as dense as Earth.
The less dense an atmosphere is, the less heat it can withstand. The Earth’s atmosphere is thick enough to retain enough heat to sustain life through the so-called greenhouse effect.
But on Mars, the atmosphere is so thin that nighttime temperatures regularly drop to 150 degrees below zero Fahrenheit (-101 degrees Celsius).
So what’s the best way to give Mars an atmosphere?
Although there are no active volcanoes on Mars now – at least as far as we know – scientists could trigger volcanic eruptions through nuclear explosions. The gases trapped deep in a volcano would be released and then flow into the atmosphere. But that scheme is a bit harebrained, as the explosions would also send deadly radioactive material into the air.
A better idea: Redirect water-rich comets and asteroids to crash into Mars. This would also release gases from the planet’s surface into the atmosphere and also release the water found in comets. NASA has already shown that asteroids can be redirected – but relatively large ones, and lots of them, are needed to make a difference.
Making Mars cozy
There are many ways to warm the planet. For example, giant mirrors, built in space and placed in orbit around Mars, could reflect sunlight onto the surface and heat it up.
One recent study suggested that Mars colonists could spread airgel, an ultralight solid material, on the ground. The airgel would act as insulation and heat trap. This could be done all over Mars, including the polar ice caps, where the airgel could melt existing ice to form liquid water.
To grow food, you need soil. On Earth, soil is made up of five ingredients: minerals, organic matter, living organisms, gases and water.
But Mars is covered in a blanket of loose, dust-like material called regolith. Think of it as Martian sand. The regolith is low in nutrients, not enough for healthy plant growth, and hosts some nasty chemicals called perchlorates, which are used on Earth in fireworks and explosives.
Cleaning the regolith and turning it into something viable would not be easy. What the alien soil needs is some Martian fertiliser, perhaps by adding terminators – hardy microbes imported from Earth that can survive even the harshest conditions. Genetically engineered organisms are also possible.
Through photosynthesis, these organisms would begin to convert carbon dioxide into oxygen. Eventually, as Mars became more inhospitable to life for Earth organisms, colonists could introduce more complex plants and even animals.
Providing oxygen, water and food in the right proportions is extremely difficult. On Earth, scientists have tried to simulate this in Biosphere 2, a closed ecosystem containing ocean, tropical and desert habitats. While all of Biosphere 2’s environments are controlled, even scientists struggle to find the right balance. Mother Nature really knows what she’s doing.
A house on Mars
Buildings could be 3D printed; first, they needed to be pushed and protected until Mars could attain Earth-like temperatures and air. NASA’s Moon to Mars Autonomous Planetary Construction Technologies program is researching how to do exactly this.
There are many more challenges. For example, unlike Earth, Mars has no magnetosphere, which protects the planet from the solar wind and cosmic radiation. Without a magnetic field, too much radiation passes through for living things to stay healthy. There are ways to create a magnetic field, but so far the science is very speculative.
In fact, all of the technologies I’ve described are far beyond current capabilities at the scale needed to colonize Mars. Developing them would require a huge amount of research and money, much more than was probably possible in the short term. While the Genesis device from “Star Trek III” could lay out a planet in a few minutes, it would take centuries or even thousands of years to lay out Mars.
And there are many ethical questions to be resolved before humans start converting Mars into another Earth. Is it right to make such permanent changes on another planet?
If all this leaves you disappointed, don’t be. As scientists create innovations to terraform Mars, we will also use them to improve life on Earth. Do you remember the technology we are developing to 3D print habitats on Mars? Right now, I’m part of a group of scientists and engineers who are using that same technology to print houses here on earth – which will help combat the world’s housing shortage.
Hello, strange children! Have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.
And since curiosity has no age limit – adults, let us know what you think too. We won’t be able to answer every question, but we’ll do our best.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by: Sven Bilén, Penn State
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Sven Bilén is co-owner of X-Hab 3D, Inc. which received funding from NASA STTR to develop lunar construction technologies and develops concrete 3D printing systems. He receives funding from NASA, DARPA, and the US Air Force related to concrete 3D printing technologies.
