Is it possible that we could ever make Mars like Earth? - Tyla, age 16, Mississippi
When I was in high school, my biology teacher showed our class the science fiction film "Star Trek III: The Search for Spock."
The plot attracted me, with the description of the "Genesis Project" - a new technology that transformed a dead alien world into a world teeming with life.
After watching the movie, my teacher asked us to write an essay about such technology. Was it realistic? Was it ethical? And to channel our inner Spock: Did it make sense? This assignment had a huge impact on me.
And now, today, I am an engineer and a professor developing technologies to expand the human presence beyond Earth.
For example, I work on advanced propulsion systems to propel spacecraft beyond Earth's orbit. I help develop lunar building 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.
Keeping humans alive beyond Earth will require a great deal of time, energy and imagination. But engineers and scientists have begun to tackle the many challenges.
A partial checklist: food, water, shelter, air
After the Moon, Mars is the next logical place for humans to live beyond Earth.
But is it possible to terraform Mars - that is, to turn it into an Earth-like planet that can support life? Or is that just the stuff of science fiction?
To live on Mars, humans would need liquid water, food, shelter, and an atmosphere with enough oxygen to breathe, but also an atmosphere thick enough to retain heat and provide protection from radiation from the sun.
But Mars' atmosphere is almost entirely carbon dioxide, with almost no oxygen. And it's very thin-only about 1% of Earth's density.
The less dense an atmosphere is, the less heat it can hold. Earth's atmosphere is thick enough to hold enough heat to support life, which is known as the greenhouse effect.
But on Mars the atmosphere is so thin that temperatures regularly drop to -101 degrees Celsius (150 degrees below zero) at night.
What is the best way to give Mars an atmosphere?
Although Mars doesn't have any active volcanoes now-at least not that we know of-scientists could trigger volcanic eruptions via nuclear explosions. Gases trapped deep inside a volcano would be released and then released into the atmosphere. But that plan is a bit misguided, since the explosions would also release deadly radioactive material into the air.
A better idea: divert water-rich comets and asteroids to crash into Mars. That too would release gases from beneath the planet's surface into the atmosphere, while also releasing the water in the comets. NASA has already shown that diverting asteroids is possible, but it would take relatively large and numerous asteroids to make a difference.
Making Mars Cozy
There are many ways to heat up the planet. For example, giant mirrors built in space and orbiting Mars could reflect sunlight back to the surface and heat it up.
A recent study suggested that Mars colonists could spread aerogel, an ultralight solid material, on the ground. The aerogel would act as insulation and trap heat. This could be done anywhere on Mars, including the polar ice caps, where the aerogel could melt existing ice to create 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, dusty material called regolith. Think of it as Martian sand. The regolith is low in nutrients, not enough for healthy plant growth, and it harbors some nasty chemicals called perchlorates, which are used on Earth in fireworks and explosives.
Clearing the regolith and turning it into something viable wouldn't be easy. What the alien soil needs is some Martian fertilizer, perhaps made by adding extremophiles - hardy microbes imported from Earth that can survive even the harshest conditions. Genetically modified organisms are also a possibility.
Through photosynthesis, these organisms would convert carbon dioxide into oxygen. Eventually, as Mars became more suitable for Earth-like organisms, colonists could introduce more complex plants and even animals.
Providing oxygen, water and food in the right proportions is extremely complex. On Earth, scientists have tried to simulate this in Biosphere 2, a closed ecosystem with oceans, tropical and desert habitats. Although all of Biosphere 2's environments are controlled, even there scientists struggle to get the balance right. Mother Nature really knows what she's doing.
A house on Mars
Buildings can be 3D printed; initially, they would need to be pressurized and protected until Mars could reach Earth-like temperatures and air. NASA's Moon-to-Mars Planetary Autonomous Construction Technologies program is investigating exactly how this could be done.
There are many more challenges. For example, unlike Earth, Mars does not have a magnetosphere, which protects a planet from solar wind and cosmic rays. Without a magnetic field, too much radiation gets through to keep living things healthy. There are ways to create a magnetic field, but so far the science is highly speculative.
In fact, all of the technologies I have described are far beyond current capabilities on the scale needed to terraform Mars. Developing them would require vast amounts of research and money, probably far more than is possible in the short term. While the Genesis device from "Star Trek III" could terraform a planet in a matter of minutes, terraforming Mars would take centuries or even millennia.
And there are a lot of ethical questions that need to be resolved before people start turning Mars into another Earth. Is it right to make such drastic permanent changes to another planet?
If all this disappoints you, don't be. As scientists create innovations to terraform Mars, we will also use them to make life better on Earth. Remember the technology we are developing to 3D print habitats on Mars? Right now, I am part of a group of scientists and engineers who are using that same technology to print homes here on Earth - which will help address the global housing shortage.
Hello, curious kids! Do you have a question you'd like an expert to answer? Ask an adult to send your question to [email protected]. Tell us your name, age, and the city you live in. And since curiosity knows no age limit - adults, let us know what you are wondering too. We can't answer all questions, but we'll try our best. This article is republished from The Conversation, a nonprofit, independent news organization that brings you facts and reliable analysis to help you understand our complex world. It was written by: Sven Bilén, Penn State Read more: Sven Bilén is co-owner of X-Hab 3D, Inc., which has received funding from NASA STTR to develop lunar construction technologies and is developing 3D concrete printing systems. He receives funding from NASA, DARPA, and the U.S. Air Force related to 3D concrete printing technologies.
