RENO, NEVADA -- Where should humans plant their feet next, beyond Earth orbit? Both the Moon and Mars loom large for those wanting to put our planet in a rocket ship's rearview mirror. But each destination stirs up debate as to cost, timing, and practicality.
No doubt, one person's vision of the future can be another individual's unwanted diversion.
That was the scene at the 40th American Institute of Aeronautics and Astronautics (AIAA) Aerospace Sciences Meeting, held here January 14-17. At special sessions on space colonization, the lunar dust flew and the Martian mudslinging got heavy-handed.
Natural laboratory
For Paul Spudis, a geologist at the Lunar and Planetary Institute (LPI) in Houston, Texas, the Earth's Moon is the ideal setting for the first colony.
Making the case for the Moon's value is topped by its closeness to Earth. Being just three days away, as the rocket flies, it's an easily accessible location. Alien, yet familiar thanks to Apollo moonwalkers and robotic probes, the Moon is resource-rich terrain, Spudis said.
"My contention is that you can go anywhere on the Moon and make what you need to survive," Spudis remarked. What good is the Moon? It is a natural laboratory for planetary science, a place to observe the Universe, a source of materials and energy, and a place to learn to live and work in space, he suggested.
"An aspect of going to the Moon first is learning how to explore," Spudis said. "We can learn how to explore a planet on the Moon. It's a simple fact. We don't know what the best, optimal mix of people and machines are to explore a planet. How do machines and humans act synergistically?" he posed.
Another reason to colonize the Moon next, Spudis argued, is to ameliorate risk of future planetary missions by re-acquiring NASA's experience base through lunar missions.
Icy reception
A human return to the Moon -- and planting a lunar base there -- is made all the more feasible by purported findings of lunar ice, Spudis emphasized.
"Going to the Moon's poles. That's where I would go to make humanity's first foothold off the planet. We now know the Moon does have water, both at the north and south poles. The current estimate is on the order of 10 billion metric tons. I happen to think that's an underestimate," Spudis added.
Because that water ice is in concentrated form, far less energy to process the material is needed. Small manufacturing plants, followed by even larger processing machinery, can convert that water ice into fuel and water to support human settlers on the Moon. Also, exporting lunar polar water is "a very obvious market," Spudis suggested. Fuel made from water ice could be supplied to commercial and governmental clients operating in cis-lunar space - the distance between the Earth and the Moon, he said.
"You can make propellant … sell it, and hopefully, sell it at a profit," Spudis said.
Spudis said that the federal government does have a role in getting America back to the Moon and getting to Mars. But that role is not in colonizing those celestial bodies. "The only way we're ever going to really colonize the solar system is to produce commodities of some type that people want," he said.
And what are those products?
"I don't think we have enough imagination to imagine the markets of the next century, let alone the markets of the following century," Spudis concluded.
Water world
Go direct to Mars. Go past the rock pile that is the Moon.
"Mars is the most promising place to establish a new branch of human civilization," countered Robert Zubrin, president of the Mars Society. Historically, where best to locate a civilization has been dominated by the richness of the resources of the location involved, he said.
"It's true that the Moon is not completely bereft of resources. But compared to Mars, it's like Greenland compared to North America. Yes, there may be water at the Moon's poles. There's enough water on the Moon to cover the whole world with a layer of water a few microns thick," Zubrin said.
In contrast, Zubrin added, Mars is a water world. Current estimates are there's enough water on the Red Planet today to cover that globe some 2,000 feet (600 meters) thick -- a difference of five orders of magnitude, he said.
Sporting a 24-hour day similar to our Earth, Mars's day-night cycles are favorable for plant growth. While sunlight is more intense on the Moon than on Mars, lunar day-night cycles run in two-week time intervals. Then there's the Moon's lack of atmosphere, while the Martian atmosphere is thick enough to mask out harmful solar-flare energies, Zubrin said.
"What this means is, on Mars, we would be able to grow plants in greenhouses by natural sunlight," Zubrin suggested.
Branch office of civilization
Among other Mars pluses, Zubrin underscored that where there has been the action of water, there is the formation of many mineral ores. Furthermore, geothermal reservoirs below Mars' surface, he said, could be available and yield a huge source of energy for future colonists.
"The Moon is so resource-poor that the establishment of a colony there is vastly more difficult than establishing one on Mars," Zubrin emphasized. "We're talking about a new branch of civilization. The fundamental resources to do it are not there on the Moon … they are there on Mars," he said.
"We want to create a new society and that's all there is to it. I believe we should commence, essentially immediately, a program to send humans to Mars. I think we can have humans on Mars within 10 years. We already know more about Mars than they knew about the Moon in 1961," when then President Kennedy green-lighted America's quest to send humans to that world.
"We are certainly prepared to initiate a humans-to-Mars program now," Zubrin said. Initial sojourns back and forth to the Red Planet will set the stage for more extensive bases. "Once we can become self-sufficient on Mars, then I think we can start colonizing Mars," Zubrin concluded.
Moon base in 2010
"Going to Mars is going to require a political decision on the part of some government," said Douglas O'Handley, a space engineer for Orbital Technologies Corporation in Madison, Wisconsin. "Frankly, I don't think we're there," he argued.
On the other hand, getting to the Moon on a commercial basis is conceivable in the near future, O'Handley said. "I think a lunar base can be established by 2010 as the next step. It's doubtful whether it's going to be the United States that does it, unfortunately."
O'Handley reported on the results of a recent study on a self-sustaining lunar base. That lunar colony would manufacture raw materials and build structures for use on the Moon, building up transportation infrastructure, as well as produce oxygen, nitrogen, carbon dioxide, water and food for life support and export elsewhere.
"The colony would be considered "self-sustaining" when it can achieve the goal of surviving without any supplies from Earth for a period of 52 months," O'Handley reported.
Energy needs of a colony -- no matter where it's located -- is always a daunting issue, O'Handley emphasized. "No one is going to sell any permanent colony anywhere in the solar system unless we have nuclear power. If we have a problem in the United States with nuclear power, we can buy it from the French and let the Russians launch it. Doing that, we've eliminated the whole U.S. problem," he said.
Sustaining a lunar operation solely on solar power is worrisome. Better to have nuclear power as a primary source, with solar energy as a backup, O'Handley noted. Learning how to live, work and sustain a colony on the Moon would give a leg up on any future plan to sustain a Mars base, he added.
Could the Moon harbor evidence for how life may be sprinkled elsewhere?
O'Handley said there is growing scientific interest in the prospect that lunar water ice -- deposited directly there by impacting comets -- could carry amino acids.
"Detecting amino acids in the lunar water ice is an exciting possibility. It would do more to put the nail in the coffin as to how unique life is or how common," O'Handley said.
21st century engineering project
While the land of Oz had its "lions, tigers, and bears," Mars has algae, mosses, and lichen. Those are early ingredients for the transformation of Mars said James Graham, a scientist in the Department of Botany and Center for Limnology at the University of Wisconsin-Madison.
Over the decades, Mars has been viewed as a potential global engineering project. Numbers of scientists have speculated on how best to reset the climate clock on Mars back to an earlier time. Doing so is called "terraforming" -- the ability to transform the dry and cold Mars we know today into one that is more Earth-like.
For example, spreading dark substances over Mars' polar caps, thereby inducing them to melt and thicken the atmosphere was one idea, Graham said. Another proposal was to orbit the planet with giant reflecting mirrors. These huge reflectors would focus additional sunlight onto the Martian surface and ostensibly raise the planet's temperature.
More recently, and arguably more reasonable research, suggests that the manufacture and release of greenhouse gases on Mars could be used to drive the globe's climate to a warmer stable state.
A Mars makeover
Looking into the future, Graham said he assumes an opening chapter of planetary engineering will be giving Mars a denser atmosphere. That condition is one in which liquid water is stable, and a higher average surface temperature is present on the planet.
Given those conditions, Graham said, there are Earth organisms that might one day be transplanted to Mars to effect the early stages of the biological terraforming of the Red Planet.
There are two start-up stages, Graham outlined, in giving Mars a makeover.
First, the microbial stage where a variety of photosynthetic microbes, including algae and cyanobacteria would establish a self-sustaining biosphere and begin the transformation of the Martian regolith and atmosphere.
Fast growing green algae, like that found in the Antarctic, Graham reported, are able to survive repeated freezing and thawing - of considerable value in an early terraformed Mars environment. Another class of algae, Micrasterias denticulata, which grows in ponds within the alpine moorlands, has been shown to have a high resistance to strong radiation, he said.
Cyanobacteria are widespread members of lakes, streams, and soils, and also commune in Antarctica, especially in the Dry Valleys region. Using "screening pigments and quenching agents," cyanobacteria fend off ultraviolet radiation, and are known to have mechanisms for repair of damage to their DNA. These attributes and others make them good candidates for the terraforming of Mars, Graham said.
Repeat roll
Following the transformations effected by the microbial stage, Graham said he terms the next step as the "bryophyte stage" of terraforming. Bryophytes are extremely important in terrestrial polar and alpine ecosystems where the severe climate prohibits flowering plants.
"More than 460 million years ago, bryophytes once had a significant part in terraforming Earth. Perhaps at some point in the future, they will repeat their role on Mars," Graham noted.
In a second stage, mosses and lichens would be introduced on Mars. They would fix atmospheric carbon dioxide into degradation-resistant organic compounds and transform the atmosphere into one with appreciable amounts of oxygen. This action, in turn, opens the way for flowering plants and eventually agriculture on the surface of Mars, Graham said.
"Lichens are important as Martian colonists. They are a pioneer species that can break down rocks, helping to form mineral soils and create conditions permitting other plants to be introduced to Mars," Graham emphasized. Mosses, too, will likely play an important role in terraforming by sequestering large amounts of carbon dioxide in the form of decay-resistant organic compounds in future Martian peatlands, he added.
Graham advised that further research is needed to improve our understanding of the physiological and ecological roles organisms might play in terraforming Mars.
At present, cyanobacteria, algae, lichens and mosses, he concluded, are top candidates in kick-starting the renovation of the Red Planet into an Earth II.
So, the Moon or Mars … which shall it be? As the AIAA program ended, while many were enlightened about the prospects for human explorers tromping across those worlds this century, the real debate here in America must play out in the halls of Congress and in the minds of the taxpaying public.
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