Project for the 21st century: mining lunar resources
THOMAS O. Paine has a love affair with the moon. He sent men there when he headed NASA 16 years ago. And as chairman of the National Commission on Space (NCS), he now joins 14 other commissioners in urging the United States to build a lunar outpost within 20 years.
Critics of the Congressionally mandated NCS study call it the dream of science fiction buffs. But the senators and congressmen who will hold hearings on the NCS report later this month had better take it seriously. Its vision of a 21st-century American space program that moves human activity out into the inner solar system has a great deal of practical analysis behind it.
Returning to the moon is a case in point.
As Paine explained recently, the NCS proposals emerged from an analysis of past economic growth and a projection of the economy of 21st-century America. That economy will include space activity. And the economics of conducting such activity require serious consideration of the moon's wealth.
Two of the most important lunar resources are oxygen and building materials.
Moon soils average 40 percent oxygen by weight, to judge from samples brought back by astronauts and Soviet probes. Combined with hydrogen brought from Earth, this oxygen could be used to make water and fuel rockets. The moon -- or more accurately, a spaceport in lunar orbit -- could literally become a refueling station for spaceships cruising the inner solar system.
Initial experiments also suggest these soils could make excellent concrete. Construction Technology Laboratory, working under NASA contract, has made lunar concrete that's stronger than its high-strength terrestrial counterpart. It tests out at 10,800 pounds per square inch (psi), as opposed to 10,260 psi for the sand-based Earth material.
As Paine notes, ``One of the fundamental economic facts of the inner solar system is the energy requirements to move through it.'' And one of the most costly requirements is climbing out of Earth's gravity. Taking material from Earth into space is like hauling cargo up a 4,000-mile high mountain.
Next-century space operators will go out of their way to avoid that climb. It will be far cheaper, in terms of energy, to take material from the moon, which has only one-sixth earth gravity, or from Mars, with one-third earth gravity. Taking water and other materials from asteroids or even from the Martian moons Deimos and Phobos could be particularly attractive, since the gravitational penalty would be almost nil.
But for oxygen, and especially for building materials, the moon could be an attractive source for near-Earth space projects. Mining lunar resources doesn't have to be astronaut-intensive. You don't need space-suited workers shoveling soil into hoppers nor on-site operators to run factories. Robotic factories controlled remotely from Earth or from an orbiting space station are the likely way for lunar industries to go.
The space tug, which TRW, Inc., is developing for NASA, will preview such tele-operation. This tug will be a rocket-powered craft that carries satellites and other cargo between low and high orbits, or that brings satellites to a space station or the shuttle for repair. The version of this craft for which TRW won the development contract last month can be operated remotely from a space station or from Earth. Instruments and television cameras will allow the ground-based operator to manipulate the craft almost as easily as if he or she were aboard it.
Remotely controlled factories with ``smart'' equipment, rather than humans, on their floors will be developed for many purposes right here on Earth. There's nothing science fictional about expecting such technology to be available by the year 2005, when the NCS suggests it could be used to support an outpost on the moon. The NCS foresees this outpost evolving into a permanently manned base by 2015. But it could be operated remotely, with only occasional astronaut visits in the beginning.
This is the sort of visionary project that probably will seem quite sensible when today's children -- who will carry it out -- have grown up. They will take robotics and space operations for granted. As Paine says, they will very likely look back at us and wonder why we ever doubted the practicality of what will be to them such obviously worthwhile activities.
A Tuesday column. Robert C. Cowen is the Monitor's natural science editor.