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SimEarth: Terraforming Mars by the Numbers
An anonymous reader writes "Today NASA has an online terraforming simulation based on the McKay/Zubrin/Fogg model of Mars' weather modification. The simulation shows that the greening of Mars can be done in at least three ways: 1) mirrors melting stored carbon dioxide in tropical soil and polar dry ice; 2) a fluorocarbon (CFC) factory; 3) blowing a vent thruster in the side of a methane-rich asteroid and engineering a collision (perhaps many impacts, but a mere 0.3 km/s impulse drive if using an outer solar system asteroid, such as Chiron, beyond Saturn). Irrespective of the merits or wisdom of these huge engineering projects, their simulation allows moving back the clock to a previous time when Mars was blanketed by greenhouse gases, and thus much warmer."
What do they plan to do about the fact that Mars has a very weak magnetic field, which is why it lost its atmosphere to begin with?
Without creating a large magnetic field to shield mars from the solar wind, any terraformation will only be temporary.
if i own an object and drop it on the side of the road, and don't come back for months ... that doesn't change the fact that i own the object. if someone else comes along and asks if it's been abandoned -- the answer is probably yes. the question is then: if he/she picks it up and uses it, is that illegal? will anyone come after him/her for doing so?
even if i own the object and -could- complain, by having abandoned it i've stopped paying attention. thus, it's rather safe to use, even though it's someone's property. not by legality, but by practicality.
"Insightful"? Insightful is realizing the trip to Mars doesn't have to be zero-G. Ever hear of a centrifuge? Send two ships. Tether them. Spin about common CG.
If all this should have a reason, we would be the last to know.
I'm going to assume that you're making a statistical argument about cosmic rays, and not talking about some novel weapon developed by Martians for the war of the worlds.
Estimates of radiation exposure for interplanetary travel (that I've seen) are typically around 50 to 100 rem per year of exposure. Delivered over a brief period, this dose would indeed cause serious effects. Spread out evenly over the course of a pair of six month trips (say) this dose is much more manageable. Radiation workers in Canada and the United States are already permitted up to 5 rem per year. I know a few people (doctors who have been involved in clinical radiation therapy) who have received lifetime work related doses of more than 50 rem, and they seem pretty healthy still. There would be a continuous low level of cellular damage, but not above the rate that the body can easily repair. There would also be an increase in lifetime cancer risk of anywhere from 0.1 to 10% depending on who you ask. I'd certainly be willing to take that chance for the opportunity to go to Mars. Even a dose of 150 rem associated with a three-year journey is not intolerable, since it is delivered over an extended period of time. I have to die of something; it might as well be cancer. The health data associated with my demise could also be quite valuable.
Incidentally, even if every cell in your body was exposed to a cosmic ray, that's not particularly alarming. Damage would have to be done to genetic matter in the cell nucleus to kill or mutate the cell--and the nucleus isn't that big a target. Cells can also repair some types of radiation-induced damage to DNA.
~Idarubicin
That's not an inconsequential engineering problem. You have to deal with making sure that the anchor between the two ships can hold up to the force of them seeking to tear apart from each other for three years. Then, you have to worry about how to handle course corrections while spinning, hooking up and accelerating to a 1G force, and detaching and braking once you arrive. These are not trivial tasks for multi-ton objects carrying passengers, lander units, and enough supplies and fuel to make the round trip. Furthermore, what sort of planning to you do for in case the tether between the two ships breaks?
I think you're overly optimistic about the prospects of terraforming. No matter how successful terraforming is, it will ALWAYS be a new, different and exciting place. The geography will always be different, it will always be much colder, and it's not necessarily going to be all green like earth. Even a successful terraforming effort will leave a lot of red lying around. I don't think terraforming will take away from Mars's uniqueness and adventure.