When I was in middle school, my biology teacher showed our class the sci-fi movie “Star Trek III: The Search for Spock.”

The plot drew me in, with its depiction of the “Genesis Project” – a new technology that transformed a dead alien world into one brimming 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: Was it logical? This assignment had a huge impact on me.

Fast-forward to today, and I’m an engineer and professor developing technologies to extend the human presence beyond Earth.

For example: I’m working on advanced propulsion systems to take spacecraft beyond Earth’s orbit. I’m helping to develop lunar construction technologies to support NASA’s goal of long-term human presence on the Moon. And I’ve been on a team that showed how to 3D-print habitats on Mars.

To sustain people beyond Earth will take a lot of time, energy and imagination. But engineers and scientists have started to chip away at the many challenges.

A partial checklist: Food, water, shelter, air

After the Moon, the next logical place for humans to live beyond Earth is Mars.

But is it possible to terraform Mars – that is, transform it to resemble the Earth and support life? Or is that just the musings of science fiction?

To live on Mars, humans will need 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 virtually no oxygen. And it’s very thin – only about 1% as dense as the Earth’s.

The less dense an atmosphere, the less heat it can hold on to. Earth’s atmosphere is thick enough to retain enough heat to sustain life by what’s known as the greenhouse effect.

But on Mars, the atmosphere is so slight that the nighttime temperature drops routinely to 150 degrees below zero Fahrenheit (-101 degrees Celsius).

So what’s the best way to give Mars an atmosphere?

Although Mars has no active volcanoes now – at least as far as we know – scientists could trigger volcanic eruptions via nuclear explosions. The gases trapped deep in a volcano would be released and then drift into the atmosphere. But that scheme is a bit harebrained, because the explosions would also introduce deadly radioactive material into the air.

A better idea: Redirecting water-rich comets and asteroids to crash into Mars. That too would release gases from below the planet’s surface into the atmosphere while also releasing the water found in the comets. NASA has already demonstrated that it is possible to redirect asteroids – but relatively large ones, and lots of them, are needed to make a difference.

Making Mars cozy

There are numerous ways to heat up the planet. For instance, gigantic mirrors, built in space and placed in orbit around Mars, could reflect sunlight to the surface and warm it up.

One recent study proposed 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 all over Mars, including the polar ice caps, where the aerogel could melt the existing ice to make liquid water.

To grow food, you need soil. On Earth, soil is composed of five ingredients: minerals, organic matter, living organisms, gases and water.

But Mars is covered in a blanket of loose, dustlike material called regolith. Think of it as Martian sand. The regolith contains few nutrients, not enough for healthy plant growth, and it hosts some nasty chemicals called perchlorates, used on Earth in fireworks and explosives.

Cleaning up the regolith and turning it into something viable wouldn’t be easy. What the alien soil needs is some Martian fertilizer, maybe made by adding extremophiles to it – hardy microbes imported from Earth that can survive even the harshest conditions. Genetically engineered organisms are also a possibility.

Through photosynthesis, these organisms would begin converting carbon dioxide to oxygen. Eventually, as Mars became more life-friendly to Earthlike organisms, colonists could introduce more complex plants and even animals.

Providing oxygen, water and food in the right proportions is extraordinarily complex. On Earth, scientists have tried to simulate this in Biosphere 2, a closed-off ecosystem featuring ocean, 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 is doing.

A house on Mars

Buildings could be 3D-printed; initially, they would need to be pressurized and protected until Mars acquired Earthlike temperatures and air. NASA’s Moon-to-Mars Planetary Autonomous 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 a planet from solar wind and cosmic radiation. Without a magnetic field, too much radiation gets through for living things to stay healthy. There are ways to create a magnetic field, but so far the science is highly speculative.

In fact, all of the technologies I’ve described are far beyond current capabilities at the scale needed to terraform Mars. Developing them would take enormous amounts of research and money, probably much more than possible in the near term. Although 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 to resolve before people get started on turning Mars into another Earth. Is it right to make such drastic permanent changes to another planet?

If this all leaves you disappointed, don’t be. As scientists create innovations to terraform Mars, we’ll also use them to make life better on Earth. Remember the technology we’re developing to print 3D habitats on Mars? Right now, I’m part of a group of scientists and engineers employing that very same technology to print homes here on Earth – which will help address the world’s housing shortage.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A view of Mars on August 26, 2003.
| Photo Credit: NASA/AP

The idea of transforming Mars into a world more hospitable to human habitation is a regular feature of science fiction. But could this be done in real life?

Scientists are now proposing a new approach to warm up the earth’s planetary neighbour by pumping engineered particles —similar in size to commercially available glitter and made of iron or aluminium — into the atmosphere as aerosols to trap escaping heat and scatter sunlight toward the Martian surface. The idea would be to augment the natural greenhouse effect on Mars to raise its surface temperature by roughly 28º C over a span of a decade.

This alone would not make Mars habitable for people, but the scientists who developed the proposal see it as a potentially doable initial step.

“Terraforming refers to modifying a planet’s environment to make it more earth-like. For Mars, warming the planet is a necessary, but insufficient, first step. Previous concepts have focused on releasing greenhouse gases, but these require large amounts of resources that are scarce on Mars,” said University of Chicago planetary scientist Edwin Kite, who helped lead the study published this week in the journal Science Advances.

“The key elements of our paper are a novel proposal to use engineered nanoparticles to warm Mars’ atmosphere, and climate modeling that suggests this approach could be much more efficient than previous concepts. This is important because it presents a potentially more feasible method for modifying Mars’ climate, which could inform future Mars exploration strategies,” Kite added.

NASA has sent robotic rovers to explore the Martian surface and the InSight Lander to study the planet’s interior. The U.S. space agency’s Artemis program aims to put astronauts in the coming years on the lunar surface for the first time since 1972 in preparation for potential future human missions to Mars.

There are numerous challenges to human settlements on Mars: lack of breathable oxygen, harmful ultraviolet radiation due to its thin atmosphere, salty soil hostile to growing crops, dust storms that sometimes cover much of the planet and more. But its frigid temperatures are a serious impediment.

“We propose to show that the idea of warming Mars isn’t impossible. We hope that our finding encourages the broader scientific community, and the public, to explore this intriguing idea,” said study lead author Samaneh Ansari, a doctoral student in the electrical and computer engineering department at Northwestern University in Illinois.

The median Martian surface temperature is about -65º C. With its tenuous atmosphere, solar heat on the Martian surface readily escapes into space. The proposal would aim to allow liquid water to exist on the surface of Mars, which has water in the form of ice at its polar regions and its subsurface.

The scientists proposed continuously releasing tiny rod-shaped particles — nanorods — into the atmosphere at a rate of about eight gallons (30 liters) per second for years.

“The idea is to either ship the material or better yet, ship the manufacturing tool and make the nanorods on the planet since iron and aluminum are abundant on the surface of Mars,” Ansari said.

The researchers are mindful of the possibility of unintended consequences in terraforming another world for humankind’s benefit. Scientists, for instance, are eager to learn whether Mars has harboured life in the past — or perhaps currently, in the form of subsurface microbes.

“Although nanoparticles could warm Mars, both the benefits and potential costs of this course of action are currently uncertain. For example, in the unlikely event that Mars’ soil contains irremediable compounds toxic to all earth-derived life, then the benefit of warming Mars is nil,” Kite said.

“On the other hand, if a photosynthetic biosphere can be established on the surface of Mars, that might increase the solar system’s capacity for human flourishing,” Kite added. “On the costs side, if Mars has extant life, then study of that life could have great benefits that warrant robust protections for its habitat.”

NASA has announced the first detection of possible biosignatures in a rock on the surface of Mars. The rock contains the first martian organic matter to be decisively detected by the Perseverance rover, as well as curious discoloured spots that could indicate the past activity of microorganisms.

Ken Farley, project scientist on the mission, has called this “the most puzzling, complex, and potentially important rock yet investigated by Perseverance”.

Perseverance is part of Mars 2020, the first mission since Viking that is explicitly designed to seek life on Mars (officially, to “search for potential evidence of past life using observations regarding habitability and preservation as a guide”). Arguably, that objective has now been achieved: potential evidence for past life has been found. But much more work is needed to test this interpretation of the data. Here’s what we do know.

Since landing in Jezero crater a few years ago, Perseverance has traversed a series of rocks formed nearly four billion years before present. Mars back then was far more habitable than the cold, dry, toxic red planet of today.

There were thousands of rivers and lakes, a thick atmosphere, and comfortable temperatures and chemical conditions for life. Many of the rocks in Jezero are sedimentary: mud, silt and sand dumped by a river flowing into a lake.

The new discovery concerns one of these rocks. Informally named “Cheyava Falls” (a waterfall in Arizona), it is a small reddish block of what looks like a mudstone, enriched with organic molecules. The rock is also laced with parallel white veins. Between the veins are millimetre-scale whitish spots with dark rims. For an astrobiologist, all these features are intriguing. Let’s take them one-by-one.

First, “organic molecules”, are made of carbon and hydrogen (commonly with sulphur, oxygen or nitrogen as well). Examples include the proteins, fats, sugars, and nucleic acids from which all life as we know it is constructed.

Organic matter is common in rocks on the earth, most of it derived from the remains of ancient organisms. But the term “organic” is slightly misleading: such molecules can also be produced by non-biological reactions (in fact, we know this was happening four billion years ago on Mars).

Simple non-biological organic molecules are common in the universe, and NASA’s Curiosity rover already found them in mudstones in Gale Crater. They were also reportedly detected by Perseverance in Jezero crater last year.

Nevertheless, Ken Farley considers the new observation the first truly “compelling detection” of organics made by Perseverance. NASA has not told us which types of organic molecules are actually present in Cheyava Falls, so it is hard to evaluate their origins. They could turn out to be biological, but a full analysis using laboratories on the earth would be needed to settle this question.

Next, the veins. These are composed of calcium sulphate, which precipitated like limescale when liquid water ran along fractures in the subsurface. Veins like these are common in Martian sedimentary rocks (Curiosity saw plenty of them), and of course they are not “biosignatures” even though they normally represent habitable conditions.

My own work has shown that microorganisms inhabiting subsurface fractures can produce chemical fossils that get trapped in calcium sulphate veins. Strangely, however, the veins in Cheyava Falls also contain olivine, an igneous mineral. This might suggest that the water was injected at temperatures too high for life. We need more data to know one way or the other.

Finally, what about those whitish, discoloured spots? These look like the “reduction spots”, also called “leopard spots”, commonly seen in red sedimentary rocks on the earth. Such rocks are rusty-red because they contain an oxidised form of iron. When chemical reactions modify the iron to a less oxidised state, it becomes soluble. Water carries the pigment away leaving a bleached spot behind.

On the earth, these reactions are often driven by subsurface-dwelling bacteria. They use the oxidised iron as a source of energy, just as you and I use oxygen in the air. On Mars, bacteria-like organisms could have used the organic matter in the rock to complete the reaction (just as we use glucose from the food we eat).

Reduction spots haven’t been seen before on Mars, although bleached linear “halos” observed by Curiosity in Gale crater are somewhat similar. As one of the few astrobiologists to have studied reduction spots on the earth – and found evidence for biological processes within them – I am personally delighted. But as ever, caution is needed.

Potential non-biological causes need to be explored and ruled out. Iron-dissolving reactions can and do happen in sedimentary rocks without life. The dark margins of the Cheyava Falls spots are enriched in both iron and phosphate, an association previously suggested to occur around some calcium sulphate veins on Mars. This observation is consistent with life, but also with chemical reactions driven by acidic fluids.

The new findings will nevertheless embolden those calling on NASA and the European Space Agency to proceed with the troubled multi-billion-dollar sample retrieval programme, which Perseverance was supposed to begin. The rover has now cored out a piece of the Cheyava Falls rock. If current plans are realised – a big if – then future spacecraft will collect this piece (and others) and bring it to the earth.

It will then be analysed in state-of-the-art laboratories far more capable than the instruments aboard Perseverance. Until that happens, we cannot be sure whether Perseverance has really found fossils of ancient life on Mars. The evidence so far is not definitive, but it is certainly tantalising.

Sean McMahon is reader in astrobiology, University of Edinburgh. This article is republished from The Conversation.