High Frontier can help Mars Direct

In response to sentences from my earlier e-mail and Mark's e-mails under the above title:" And that a garden in a green house on the Moon seems more likely to succeed than one on Mars, since there is less gravity and no winds on the Moon, the average temperature is higher, and it is days travel time from Earth rather than the months it is to Mars. I suspect you're right. Zubrin makes the opposite argument. He states that growing crops on any airless body is impossible because he assumes the glass would have to be sufficiently thick to screen out radiation. Of course that's not the method suggested by O'Neill, but we can leave space mirrors the size of cornfields right out of our thinking because that's just plain silly, to hear him say. But there's a fine print to his "plastic wrap" crop fields on Mars which require neither thick glass nor radiation shielding; one which Mars advocates sometimes overlook. It assumes a many-decades-long effort to thicken the Martian atmosphere via release of CF's at a rate comparable to current global production levels. As things stand right now (and for many decades to come), the pressure vessel for a Martian greenhouse would need to be no less sturdy than one for the moon or HEO. The chief difference would be the relative levels of insulations." There were studies of how nuclear or ionizing radiation (which is what cosmic rays are) effects plants 35 to 40 years ago, and the results are that plants can take powers of ten more than animals can. There was a Scientific American article on this, and I am sure a lot of more detailed articles then and since. Meaning gardens can grow with shielding from cosmic radiations, but the gardeners must limit the time they spend in their unshielded gardens. From what Mark said, Zubrin is way off on this. There are other issues for a "plastic wrap" garden on Mars. Mars has no oxygen in its atmosphere and so no ozone protection from the hard solar ultra-violet radiation. Plastic left outside on Earth breaks down in a few months or years from the soft ultra-violet which gets through our ozone layer. Exposed plastic wrap would rapidly be destroyed on Mars. Another issue for gardens everywhere that use "regolith" for soil, is oxygen. When green cells first started producing oxygen from photosynthesis onEarth, the oxygen was consumed in oxidizing the iron and other materials in Earth's surface, so essentially no free oxygen appeared in the atmosphere for millions of years. The soils of Mars, the Moon and asteroids, will be a sponge for oxygenalso, and plantsrootsmust have oxygen in the soil or the roots will die. Roots of green plants use oxidative respiration like we do, consuming oxygen and sugars, to stay alive. The green plant parts above the ground produce oxygen only when "the Sun shines", but when in the dark they also consume oxygen. Studies on soy beans suggest that they do best with about 5 % oxygen. And, in response to " I have been warming to the idea of colonizing the Moon. I don't want to subvert the goals of this group, but it might be useful to discuss that in detail. Discussion is fine, but I doubt I'll ever feel that the moon as a location for permanent settlement could effectively compete with orbital habitats. I feel that all the points which O'Neill made about the disadvantages of a planetary location apply to the moon. I'm sure the moon, as a nearby source of raw materials outside the steepest parts of Earth's gravity well, will see significant development. But I don't anticipate the moon being settled in a manner analogous to the settlement of the New World." My thinking about the High Frontier (and O'Neill habitats) is that they are the only way to achieve the full potential of space, but I suspect there is a roll for a lunar colony in the near future. Sort of like St. Louis, Missouri in opening the western part of the United States. St. Louis served both those going to Kansas and California, and I can see that the Moon could serve those going to O'Neill habitats in cis-lunar space, to highly eccentric Solar orbits, Mars, the main belt asteroids, the Trojan asteroids, and where-ever. Best wishes, Jay Huebner