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Major ice discovery excites Mars researchers (part 1)
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By now, you’ve probably heard the big news about NASA’s recent discovery of water on Earth’s moon. Unfortunately, the timing of that story drowned out a much bigger story – a real shocker with far greater implications for the future of space exploration and settlement.
Did you hear that a team of space scientists discovered ice on Mars … again? The researchers studied several small, fresh, mid-latitude craters on Mars and found strong visual and spectroscopic evidence of ice within the craters or their ejecta blankets. Over a few weeks or months, the ice sublimated away, as one would expect of ice on Mars.
Both press releases coincided with the September 25th, 2009 edition of Science Magazine, which highlights the results from both teams. The news about lunar water generated a vast majority of the media buzz because the surprising headline seems so implausible. Water on the Moon? Are they crazy?
Meanwhile, the ice-on-Mars story passed beneath the radar screen. Yawn, ho-hum. NASA discovers ice on Mars every day, right?
Yes – and no. This latest discovery is vastly different… and in part two of this report, I’ll explain exactly why. But first, let’s learn some important lessons about water from our best teacher, the Earth. We’ll also take a brief tour of our solar system.
Learning from Mother Earth
Scientists have known for decades that our solar system abounds with water. All water is not equal, however. The closest water-world, Earth, teaches us some important lessons about water - and most importantly, its ability to support life, i.e. us.
Earth possesses water in many quantities, forms, and locations. Oceans, ice caps, underground aquifers, atmospheric vapor, hydrated minerals, etc… the Earth stores its vast water supply in ways which translate into varying degrees of usefulness for its ambitious natives. Water is life and food, energy and industry.
Looking closer at these three critical requirements for supporting plant life and human civilization:
Quantity: Water shortages (droughts) mean turmoil and painful death for crops and people.
Location: Vast, pure-water oceans in underground aquifers wouldn’t help desert-dwellers if they lack the means to reach the water, either because it is too deep or too far away.
Form: Likewise, oceans of salt-water can’t satisfy the thirst of a single person or plant.
Technology often mitigates shortcomings in any of these areas. For example, given enough energy, we can boil salt-water and condense the vapor into drinking water. We can reach aquifers by drilling wells or transport pure water from lakes and rivers hundreds of miles through pipelines. We can even release water by heating minerals or create it by combining hydrogen and oxygen directly. These technologies require time, investment, and infrastructure long before we drink the rewards. More conversions require more technology at greater cost and/or time.
Therefore, Earth teaches us that plants and low-tech humans may thrive assuming they can access a) a vast quantity of water; b) in the right forms; c) and the right locations. We need to satisfy all three requirements. Even then, there’s no guarantee that life will flourish… but at least we have a fighting chance.
A brief tour of our solar system
Keeping the three main requirements in mind, let’s look around our solar system and see what places seem the friendliest for life and human settlements. Furthermore, let’s assume current or near-future levels of technology. This isn’t Star Trek, nor is it
Sunward, the outlook for water is poor. The poles of Mercury may contain some sheltered ice, but these locations would be extremely difficult for us to reach. Blast-furnace temperatures have baked the surface of Venus bone-dry. Sun-grazing and near-Earth asteroids and comets may contain ice in small quantities if conditions are just right for preserving the ice, but no one has ever proposed a reasonable way of accessing or using this water.
Farther out, the asteroid belt may shelter ice within some asteroids or “burnt-out” comets. However, the main belt is also difficult to reach with current technology. We can’t formulate realistic plans for harnessing the potential resources of the asteroid belt without critical knowledge about the locations, quantities, and properties of those resources… and the most important and elusive resource is water.
Asteroid researchers are hard at work, and we learn more every day. For example, a recent paper suggests meltwater debris flows on asteroid Itokawa. Other researchers explain the Itokawa findings by enlisting dry processes like YORP.
The main belt guards its secrets well. Thus, it remains a destination for the farther future.
The outer solar system contains vast amounts of water-ice, but again, the main problems are location and access. Three of Jupiter’s largest moons (Europa, Ganymede, and Callisto) are ice worlds, as is Enceladus, a moon of Saturn. Saturn’s rings contain ice crystals, and ice-rich comets probably dominate the Kuiper Belt and Oort cloud. Human explorers can’t reach any of these locations with current technology, however… so the outer solar system remains the exclusive domain of robotic probes for the near future.
What’s left? Earth’s moon, and Mars.
The Moon: good location, but the judges deduct major points for poor form and quantity
In terms of propulsive energy, Earth’s moon is the third-easiest rocky destination in the solar system to reach – trailing some near-Earth asteroids and Mars. Archives of NASA samples and images from the Apollo missions in the 1960’s and 1970’s give us more detailed, hands-on knowledge of the Moon than any other solar system body.
We’ve touched and tasted the Moon. Until recently, we thought most parts were bone dry - except perhaps some sheltered, hard-to-access craters near the lunar poles. Therefore, the recent lunar water announcement does come as a big surprise, and the topic deserves ample media attention.
Unfortunately, even after the recent announcement, lunar water still fails the critical “form” and “quantity” requirements for future exploration and settlement. Settlers could claim cupfuls of water only if they collect and bake tonnes of lunar regolith. Using water for long-term lunar crop growth and as a fuel source minimally requires many thousands of tonnes of water, therefore millions of tonnes of regolith must be processed.
Lunar regolith collection and baking processes require a high level of technology and infrastructure, which means time and major investment. Without a clear return on that investment, governments, corporations, and/or wealthy individuals will continue to shun lunar settlements (i.e. we still face the same economic issues with lunar settlements as we’ve always faced).
Mars: the last planet standing
This brings us back to the discovery of ice on Mars - again. Even before the recent study of small, fresh craters, some select locations on Mars offered future explorers and settlers the best balance of location, form, and quantity. The recent findings reinforce that conclusion while offering some new, attractive options to Mars mission planners and pesky economics majors.
But why? Well, a good explanation requires a thorough review of our current thinking with regards to Mars mission planning, both inside NASA and outside. Since the
Fortunately, your faithful Denver Space Industry Examiner happens to be a leading expert in this exciting field. I'll guide you through the most relevant, slippery details in part two of this report (two weeks from now, most likely).
Lead image credit:
International Astronomical Union
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