Gregg Maryniak on Economist.com

The debate has moved on to another module.
http://www.economist.com/debate/days/view/359/showCommentModule:1

Here's the comment I submitted:

Dear Madam,

Neither a manned mission to the Moon nor one to Mars should be our next major goal. However, people should return to the Moon at some point, and we can't tell whether NASA should be involved because that depends on how things develop over the next generation of space activity. Our next major goal should be to bring enough asteroid material to near-Earth space to support industry that doesn't depend on lifting materials from Earth's surface.

Unmanned science missions should continue and expand. Their funding should not be jeopardized by rob-peter-pay-paul schemes for plant-the-flag missions. They should go to all the planets and moons, to various asteroids and Kuiper-belt objects, and to Lagrange points for long-term observations without the interference of Earth's various forms of electromagnetic noise.

I disagree with Mr. Maryniak's statement that "the goal of activity in space should be to improve life on Earth." The goal of activity in space should be to improve life, full stop. People should live in space, permanently. The terrestrial biosphere doesn't have the resources to support a hundred billion humans; the solar system does.

The Moon is the closest major source of raw materials to Earth -- in distance. But distance is not what matters most in space. What matters most is delta-vee: how much do you have to accelerate your payload to get it to the destination. In terms of delta-vee, numerous near-earth asteroids are closer than the Moon.

The Moon has oxygen. But so do most objects in space. The Moon's basalt can provide silica (glass), some metals such as aluminum and magnesium, and basalt fiber (a high-tensile-strength material similar to fiberglass). But asteroids have a much wider range of raw materials than the Moon does. You can make almost anything out of the elements found in carbonaceous asteroids: plastic, carbon-fiber composites, solvents, lubricants, food, rocket propellant, ordinary fuel for use in fuel cells. Stony asteroids have materials similar to lunar ones, and more. Metallic asteroids have metals that don't have to be separated from silicon and oxygen in an energy-intensive chemical process.

The Moon can provide a base at the bottom of a smaller gravity well than Earth's, launching a narrow range materials to low earth orbit. Near-earth asteroids can provide the entire resource base for a civilization in space, without the disadvantage of being at the bottom of the Moon's gravity well.

--- In spacesettlers@yahoogroups.com, "Combs, Mike" wrote: