The Wet Side of the Moon [via Nina Reznick]




http://www.nytimes.com/2009/11/20/opinion/20marshall.html?_r=2&th&emc=th

November 20, 2009
Op-Ed Contributor

The Wet Side of the Moon

Moffett Field, Calif.

PICTURE a habitat atop a hill in warm sunlight on the edge of a crater near the south pole of the Moon. There are metal ores in the rocks nearby and ice in the shadows of the crater below. Solar arrays are set up on the regolith that covers the Moon’s surface. Humans live in sealed, cave-like lava tubes, protected from solar flares and sustained by large surface greenhouses. Imagine the Moon as the first self-sustainable human settlement away from Earth and a high-speed transportation hub for the solar system.

We can finally begin to think seriously about establishing such a self-sufficient home on the Moon because last week, NASA announced that it had discovered large quantities of water there.

While we have known for decades that the Moon had all the raw chemicals necessary for sustaining life, we believed they were trapped in rocks and thus difficult to extract. The discovery of plentiful lunar water is of tremendous importance to humanity and our long-term survival.

There have been 73 missions, manned and unmanned, to the Moon, and understanding its chemical composition, particularly finding water, has always been a priority. So why haven’t we seen significant amounts of water until now?

The answer lies in the Moon’s rotation. Unlike Earth, which rotates on a significant tilt to the Sun, the Moon is barely tilted at all. At the poles, some hills remain in permanent sunlight while some troughs are always in shadow. When water lands in sunny spots, perhaps carried by comets or asteroids, the water transforms directly into gas; if it lands in shadow, the water freezes and can remain indefinitely. The lack of light explains why spectrometers — instruments that can be used for remote water detection but rely on reflected light to do so — never picked up on the water.

This changed last month, when NASA shot a satellite into a permanently shadowed region on the Moon’s surface, throwing a plume of material containing water up out of the shadow.

From the perspective of human space exploration, that water is the most important scientific discovery since the ’60s. We can drink it, grow food with it and breathe it — by separating the oxygen from the hydrogen through a process called electrolysis. These elements can even be used to fuel rocket engines. (Discovering water on Mars was not quite as significant because the major hurdle to establishing permanent settlements there is the eight-month journey.)

Creating a permanent lunar habitat is important primarily for our species’ survival. Humanity needs more than one home because, with all our eggs in one basket, we are at risk of low-probability but high-consequence catastrophes like asteroid strikes, nuclear war or bioterrorism.

But it would also lead to valuable technological and other advancements. Consider the side-effects of the Apollo program: it drove the development of small computers, doubled the number of doctoral students in science and math in about a decade and marked a new stage in relations between the Americans and Soviets.

Imagine what we could learn from living on the Moon permanently. On its far side, shielded from the Earth’s radio noise, there is a quiet zone perfect for radio astronomy — which allows us to see objects we can’t from Earth. Out of necessity we could develop bacteria to extract resources directly from the regolith — a useful technology for Earth as well. And an international venture could open a new era of global cooperation.

Almost as surprising as NASA’s announcement is the lack of attention it has received. Thirty years ago, a development like this would have been heralded as one of humanity’s greatest discoveries. Perhaps the indifference is partly because of the disappointment of astronomers, amateur and professional, who tried to watch NASA’s October blast through their telescopes, but couldn’t see the plume. Or perhaps it’s a symptom of our age, that the problems that bedevil us on Earth limit our interest in other worlds — just when we need them (and the inspiration they offer) most.

William S. Marshall is a staff scientist with the Universities Space Research Association based at the NASA Ames Research Center.

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