President Bush has announced an overhaul to NASA's long-term goals and recommended that the United States once again send men (and perhaps women) to the moon. But the price tag for such ventures would be steep.
As the Seattle Post-Intelligencer noted in its Jan. 12 editorial ("It's easy: Just stop spending"), with growing federal deficits the president's goal might seem misguided. Quite apart from the political benefits, however, we actually have a stronger scientific justification for such missions now than we did three decades ago.
Significant discoveries await us that can only be made on the moon. Admittedly, the moon's virtues aren't obvious. The moon is as dull and lifeless as the Earth is colorful and vibrant. Since Earth is so well endowed, why would we want to set off on another risky venture 250,000 miles into space? Ironically, it is the moon's stability that makes it especially valuable to science.
The moon has almost no water and very weak geologic activity. As a result, it holds a vast archive of information about our solar system's deep past. Rocks on the moon remain unaltered for billions of years, although the occasional impactor smashes some into smaller bits. Most rocks on the moon are pieces of its crust broken up elsewhere on its surface. But some of the moon's regolith -- the loose rocky material that covers its surface -- is from the asteroid belt. Most important, some is meteoritic material from the Earth. Earth's surface is obviously covered with Earth rocks but not from our planet's early history.
Look through a small telescope at the moon, and you will see a few large maria (dry "seas") and many craters of various sizes. Impacts are responsible for all these features, most prior to 3.5 billion years ago. Because the Earth is so much larger than the moon, it should have experienced about 25 times as many impacts over the same period. Each large impact on Earth would have catapulted large numbers of rocks from its surface into space. Some of these fragments would have made their way to the moon.
Based on recent calculations published in the astronomy journal Icarus by author Gonzalez and two colleagues, the moon's surface probably holds about 7 parts per million of Earth material. That's about 57 tons over a 100-square-mile area.
Some of these fragments should contain important chemical clues about the origin of life, clues no longer available on Earth. Not surprising, Earth-based origin of life research has reached an impasse. There should also be rarer Martian meteorites on the moon. And, unlike rocks on Mars, the lunar versions will not have been altered by billions of years of exposure to water vapor. So they may reveal secrets about Martian history that aren't available on Mars itself.
Once we learn how to distinguish planetary meteorites from the lunar background material, we need to follow with manned missions. Realistically, only manned missions can search through large volumes of lunar material to find the few hidden gems.
Manned missions are also essential to build giant optical and radio telescopes made possible by the moon's low surface gravity. Such telescopes would profoundly extend our vision of the universe. Who knows what we might discover in the distant corners of the cosmos from the lunar platform?
Every government expenditure is a legitimate topic for public debate. But the discussion over manned lunar missions should be richly informed by the scientific fruit they would reap. On balance, such missions might turn out to be a wise investment.
Astronomer Guillermo Gonzalez of Iowa State University and NASA's Astrobiology Institute, and Dr. Jay Richards of The Discovery Institute are authors of the forthcoming book "The Privileged Planet" (Regnery 2004).