Space probes have viewed it, rovers have explored it, writers have romanticized it and cartoonists have used it for a source of material.
Some scientists, of course, simply marvel at its potential – not just as a potential target to be explored, but also for its potential as the salvation of humanity.
We’re talking Mars. And as several AAPG members observe, it’s time for the talk to be serious.
“The human species needs a frontier,” said Bruce Cutright, project manager at the Bureau of Economic Geology and a member of AAPG’s Astrogeology Committee. “It needs to be excited about the future and they need to see that the future is going to be better and be different, and that’s what space exploration in general provides.”
As Cutright and others see it, the general lack of interest in space exploration today, compared to the collective fervor there was for it in past decades, represents a significant obstacle to human advancement, so it falls to organizations like AAPG to steer the ship of public interest back on course by promoting the next logical giant leap for mankind: the exploration and terraforming of Mars.
“We believe in the spirit of the human frontier, and I think as AAPG members, we are explorationists, and that’s fully within the realm of what we talk about as geologists and engineers,” Cutright said. “The whole idea of terraforming Mars or colonizing the moon or creating orbital habitats – all of these things that sort of come out of the realm of science fiction – aren’t really science fiction.”
“It’s not merely an academic exercise,” added William Ambrose, research scientist at BEG and chair of AAPG’s Astrogeology Committee. “It would be part of a grand, integrated plan for the human species to go beyond just the bounds of Earth, because the entire history of the human species has been one of exploration. I think for that to end, and for we humans to be confined to earth for the rest of the history of our species, is unthinkable.”
“Do I think that Mars is worthwhile? Absolutely. It should be our next step,” concurred James F. Reilly, another member of the Astrogeology Committee who also is a former NASA astronaut, exploration geologist and current associate vice president and dean of science and technology for the American Public University System.
The trio made their case through two presentations at the recent AAPG Annual Convention and Exhibition in Denver: Ambrose and Cutright presented “Water and Other Volatiles on Mars: Resource Base and Implications for Terraforming,” followed by Reilly’s presentation of “Surviving the Red Planet: Preparing the Visiting Geologist to Live and Work on Mars.”
Recipe for a New Earth
“We do not, at least in theory, lack the means to do this,” Ambrose said about the prospect of terraforming the Red Planet. “We have the technology. Scenarios have been formulated by planetary scientists and engineers. They’ve basically figured out how this can be done.”
Ambrose and Cutright’s main blueprint comes from the work of Robert Zubrin and Christopher McKay, a renowned aerospace engineer and a NASA planetary scientist, respectively, who have jointly published a slew of papers and books on the subject.
“The whole goal when we talk about terraforming is to make the existing surface of Mars habitable by humans, and the idea is to try to make it approach the surface environment of earth as closely as possible,” Cutright said.
“It’s essentially building up a sufficient level of greenhouse gas in the Martian atmosphere so that the process of warming up Mars, and also releasing volatiles takes place without an additional input from various sources,” Ambrose said. “And that brings in the possibility of all kinds of terrestrial plants being able to live and prosper in an environment like that, and then suddenly you have the greening of Mars. It might be with anaerobic algae or bacteria or other sorts of extremophiles, but it would begin the process of terraforming Mars in a very short period of time.”
Terraforming would never make Mars exactly like Earth, however.
The air pressure would only ever be a quarter, or a third at most, of what the Earth has on most of the surface at or around sea level, so humans would never be able to exist on the surface of Mars without, at the very least, some supplemental oxygen and a pressure suit. At best, Martian atmospheric pressure would be comparable to the thin air atop the Andes Mountains on Earth – which can support human life, if only barely.
“Obviously, it will never be the same,” Cutright said. “The Zubrin-McKay approach is, ‘How can we take Mars, which is the closest to an Earth-like planet that we’ve got right now, and move it closer to being an Earth-like planet?’”
The Zubrin-McKay plan offers two main approaches: gradual, and what Ambrose and Cutright called “catastrophic.”
The gradual approach would be to slowly create and release greenhouse gases on Mars and let the normal weather patterns spread them around over time, which could be done in two ways.
The first would be by putting a massive parabolic reflector in orbit around Mars – “basically mylar or some kind of aluminized reflector that could capture the sun’s rays and focus them down onto the polar areas of Mars and heat up the surface,” Cutright said, “just the way you would take a magnifying glass and hold it over a piece of wood or something.”
The effect would be to liberate the existing carbon dioxide and water resources from the ice caps and the permafrost into the atmosphere.
The other gradual approach, Cutright described as “basically building greenhouse gas factories that take the in-situ material of Mars, which are basically chlorofluorocarbons, and introducing them into the atmosphere.
“And Mars is rich with a variety of minerals and different chemicals – there is sufficient carbon and fluorine and hydrogen where you can manufacture greenhouse gases from what we call chlorofluorocarbons,” he continued. “I think one of the key things to think about is that there is a huge volume of water on Mars, and this is one of the underlying reasons people can look at and talk about terraforming Mars as a practical approach.
“Mars is locked in an ice age. Water and carbon dioxide are already on the planet. You just need a little change to release that into the atmosphere. It actually needs the introduction of greenhouse gases if the planet is to be rendered to the point that it could be habitable for humans,” Cutright added.
The “catastrophic” approach to terraforming would be to introduce more volatiles into the Martian climate by finding ice and ammonia-rich comets and asteroids and sending them crashing down to the planet’s surface.
It would take two comets roughly the size of the Shoemaker-Levy comet that struck Jupiter 11 years ago to add sufficient volatiles like water, ammonia, carbon dioxide and methane to the Martian atmosphere to increase the atmospheric pressure, they explained.
The best candidates would be in the outer solar system, because it would take much less energy to move them into an orbital path to intercept Mars than it would to divert asteroids or comets closer to Mars.
“The basic issue is what’s called the ‘Delta-v’ – the change in orbital velocity needed to move something around the solar system, because the farther out you go from the sun, the slower the objects are moving,” Ambrose said. “It takes less energy to divert even a large object from its existing orbit to bring it into the inner solar system, and through the magic of orbital mechanics, the object can be slowed down with gravitational assists going around one of the other planets – Jupiter, Saturn, even Venus – so when we get the object toward Mars, it’s actually moving fairly slowly.”
It wouldn’t require a “big effort” to do this, he said, but it would take a little bit of effort over a long period of time to divert the orbital paths of major comets.
It would take about 10 years to locate and bring the comets into orbit around Mars, and then it would take about 40-50 years for the dust to settle, during which time the other two, more gradual methods could be used in conjunction to gradually warm the planet to habitable temperatures.
So, Ambrose and Cutright said, Mars could be turned into a more Earth-like planet in as short a time as about 50 years, according to some estimates, or up to 250 years according to others.
MSRP On a New Earth?
Of course, setting up gas-factories and orbiting reflectors and moving asteroids around the solar system is going to take some monetary investment on Earth, but the venture defies easy quantification or a simple, straightforward price tag.
“The way that people have looked at it is as a percent of gross domestic product,” Ambrose said. “Rather than a straight ‘How much is it going to cost?’ in terms of dollars, it’s ‘Could we afford 1 or 2 or 5 percent of the world’s gross domestic product to create another earth?’ By those analyses, the answer is ‘Yes, we could afford that.’”
And it would require some regular maintenance, too.
Mars is no longer geologically active, so it has no plate tectonics, which has two major implications for its habitability:
♦ First, it has no protective magnetic field like the Earth has, so any intense solar flares in Mars’ direction will strip the atmosphere by up to 30 percent at once.
“So the question is, after building up a Martian atmosphere, is it going to survive in the long term? A solution to that really hasn’t been fully addressed yet,” Ambrose said.
♦ Second, the lack of plate tectonics also means the minerals in the ground aren’t being replenished over the millennia as happens on Earth.
“Our mineral deposits that are so valuable to us here on earth are generally the product of the cycling of convective currents in the mantle and plate tectonics,” Cutright said. “We think Mars has had a lot of volcanism, so there may be some very good mineral deposits on Mars, but we just haven’t been there to find them. But they are probably more rare than what we would see on Earth.”
Both problems can be managed by regular trips to nearby asteroid belts, though.
“Mars is sitting right next to the asteroid belt, which has these huge reserves of platinum group metals, rare earth metals, all of those – iron, nickel, cadmium, chromium – are closer to Mars than they are to Earth,” Cutright said. “So when we think of terraforming Mars, we’re not thinking only of Mars; we’re thinking of the environment it sits in and the other resources that can be brought to bear to make colonization of Mars more attractive.”
“But again, because of Mars’ weaker gravity and lack of a magnetic field, the terraforming we’re talking about is not a process that’s going to maintain itself forever. It would require some level of maintenance going forward in the future,” he reiterated.
“But it would be nothing more strenuous than our efforts on Earth to protect the environment here,” Ambrose added.