A Permanent Outpost on the Moon?

A Permanent Outpost on the Moon?
By SASWATO R. DAS
Copyright by The New York Times
Published: November 24, 2009
http://www.nytimes.com/2009/11/25/opinion/25iht-eddas.html?ref=global


The discovery of a significant amount of water on the Moon, announced recently by NASA, has fired up space enthusiasts and would-be lunar colonists. Building a permanent base on the Moon suddenly seems a lot less daunting.

Cynics are already talking of humans polluting the Moon’s water, while wags are joking that it’s only a matter of time before bottled water companies get involved in harvesting lunar water, if not physically, then somehow in marketing campaigns.

NASA’s announcement of water on the Moon has also complicated things for President Obama, who hasn’t seemed very keen on resuming a manned program to the Moon.

But more than anything else, what last week’s discovery underscores is that our instruments are finally coming of age: we are witnessing another golden era of astronomy, when our instruments’ capabilities are beginning to equal those required to test our theories. (Recently, we have also confirmed the existence of black holes and seen planets around other stars; we have found that the universe is speeding up; we have seen the ripples from the beginning of the universe.)

The idea that the Moon has water is not new. In the first century A.D., the Greek historian Plutarch wrote about it in “De Facie de Orb Lunae” (“On the Face of the Moon”), when he hypothesized that the dark areas we see were seas. Four hundred years ago, when Galileo first turned his telescope to the Moon and saw its mountains and craters, he too wondered whether the dark spots were oceans. In “Siderius Nuncius” (“Starry Messenger”), which Galileo published in 1610, he wrote that the Moon’s “brighter part would represent the land surface while its darker part would more appropriately represent the water surface.”

In 1647, after years of observations, Johannes Hevelius published the first lunar map and painted large swaths of the surface blue. Four years later, the Jesuit astronomers Francesco Maria Grimaldi and Giovanni Battista Riccioli published a map of Moon that codified the nomenclature that is still in use, calling the depressions maria or seas.

Over the next two centuries, the idea of a Moon awash with oceans was kept alive by astronomers and authors, from William Herschel (the discoverer of the planet Uranus) to Jules Verne (“From the Earth to the Moon”).

Then, as astronomical telescopes got better, it appeared that the Moon is airless and waterless. And a lunar atmosphere was needed to retain water since sunlight breaks down water into its constituent hydrogen and oxygen, and the Moon’s weak gravity is unable to prevent them from escaping. Even if there had been water on the Moon at one time, it would have escaped long ago, the thinking went.

Yet some astronomers refused to give up the idea that the Moon had some water or, at least ice. The ice would have come from comets which crash onto the Moon’s surface (comets contain a lot of ice). And, they reasoned, some of the ice would remain at the bottom of craters and in areas that don’t get sunlight because of the Moon’s tilt.

The first tantalizing data that ice may indeed be present in craters near the lunar poles was suggested by the Clementine probe in 1994 and reconfirmed by the Lunar prospector in 1998. Estimates of the amount of ice on the Moon ranged from a few million tons of ice to a few billion tons, enough to fill a small lake.

This is exactly what NASA has confirmed by “bombing” the Moon last month with one of its spacecraft. Its target was Cabeus, a crater close to the Moon’s south pole, which never gets any sunlight. NASA’s Lunar Crater Observation and Sensing Satellite hit paydirt — the impact dug up significant amounts of ice from the crash site.

Another spacecraft, the Lunar Reconnaissance Orbiter was watching, and observed the water. NASA scientists said last week that about about 25 gallons had been detected, immediately and dramatically changing the viability of a self-sustaining lunar base.

Water is heavy, making transporting the huge amounts of water that would be required to maintain a lunar base prohibitively expensive. Even if the water on the Moon is present as ice near the poles, it is a much simpler proposition to get it to a lunar base using, say, a rover, than it is to ship it from the Earth. A pound of payload bound Moonwards would cost up to $100,000 to hoist.

In addition to drinking and bathing, the lunar water could be used for hydroponics to grow plants. And it could easily be broken down to give oxygen to breathe and hydrogen that could work as a fuel for rockets for the inevitable Earth vacation.

President Obama will have to factor in the hopes of space cadets as he decides the fate of NASA’s space programs. The July report by the Augustine review panel wasn’t encouraging of crewed lunar missions or a permanent lunar base. The recent announcement has raised the political stakes of President Obama’s upcoming decision.

Forty years ago, when NASA astronauts Neil Armstrong and Buzz Aldrin walked on the Moon, it seemed reasonable that the Apollo missions would be soon followed by hotels in orbit and a permanent outpost on the Moon.

They haven’t happened yet. But the discovery of ice on the Moon raises hopes again that, some day, humans may indeed live on the Moon.

Saswato R. Das is a science and technology writer in New York.