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Well, I think you have a couple small errors there. The Martian day is slightly longer than Earth's, not shorter. The wind on Mars is probably not capable of being harnessed because of the low pressure. It might be able to pick up dust and skip sand, but it probably can't spin turbines.
You should add that Moon dust is especially troublesome and has no martian analog. That one issue might be enough to make it a bad testbed. Testing mechanical devices in a lunar dust environment makes as much sense as testing them in a Hawaiian hot lava bed, it adds a critical damage characteristic that is not representative of the deployment environment. The only compelling reasons to test on the Moon are psychological, not physical.
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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau |
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Please elaborate.
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![]() Anyways I agree with both of you guys there is no point in testing equipment for mars on the moon because they are so different and better test sites can be found on earth or created in laboratories. Some testing will have to be done in space or on mars, like EDL systems. |
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Not exactly. I was pointing out what those differences are. Martian fines create their own special problems, especially with seals.
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The fact that the Martian atmosphere extends higher also means that, as you gain altitude, the density does not decrease as rapidly as on Earth. All lf the weather on Earth occurs within the first 7 miles, but on Mars, the dust storms nearly reach the top of Olympus Mons which is 15 miles high. That means that you can put wind turbines at relatively higher elevations on Mars without losing as high a percentage of the force of the wind.
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It does on Earth from time to time as well.
Given the 1/2 p v ^2 equation for dynamic pressure: Peak turbine performance on earth is typically at about 33 mph ( 15m/sec ) 1.23 kg/m^3 x 15 ^2 = 138 Pa To match that on Mars - with atmospheric pressure of 0.02 kg/m^3 - you would have to have... 138 = 1/2 * 0.02 * x^2 117 m/sec - 261 mph. So - to get peak turbine performance as produced by 33 mph winds on Earth - you would require 261 mph winds on Mars. The average wind speed on Earth ( about 6.6 m/sec ) would have to be matched by Martian wind speeds of 51 m/sec (114mph)- which is over the peak value I have seen for observed Martian winds. If you think think the very best way to spend mass budget to the surface of Mars is with wind turbines - you're mad. That they would generate SOME electricity is a certainty, some of the time - but it wouldn't be a lot and they make nowhere near as much sense as they do on Earth. What about when the wind stops? It will from time to time, for periods of time that might be anything between minutes and days - and it's not a case of 'turn off the lights' - it's a case of people dying because of failed life support. Every single iota of power you intend to generate via turbines HAS to be match by non-environmentally variable means ( i.e. small RTG derived platforms such as those proposed for Mars Direct ). If you've got the power you need from those, then why both with turbines at all. I agree, however, that the moon offers little usefull analogy to the Mars in terms of exploration systems testing. Things the Earth can't provide however - are the UV radiation - the temperature swings - the air pressure - and the simple reality of being 250,000 miles from home when something breaks down. The argument of going to the Moon so as to make going to Mars easier is without merit. But the brutal fact is that there is currently, political will to revisit the moon -and none to visit Mars. When GWB announced the VSE, I think his words describing the lunar visits as a stepping stone to Mars was a programmatic one, not an engineering or practical one. Doug Last edited by djellison; 09-February-2008 at 09:18 AM. |
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Doug,
Give him a break! Of course the air is thinner on Mars--but so is the sunlight! Everything is less good on Mars. That's why Mars is Mars and Earth is Earth. Get used to it. . . . The only thing that works the same is nuclear. Is that what you propose? __________________________________ Mental, As for testing on the Moon. What is the argument? That we need to blow off the Moon so we can go to Mars? That we can't do both somehow? Like we have to blow off the Azores so we can colonize Massechusetts? What's wrong with the Moon? Why do you hate it so much?
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The differences are not "less good " enough to rule them out. The main objection to nuclear on Mars is that it's heavy, so shipping it there is expensive in energy. Solar, as the rovers demonstrate, works and is low-maintainence, the only problems are dust and night. Wind turbines can work on Mars, according to the number-crunchers who have researched it. In terms of reliability and maintainance, it's somewhere between nuclear and solar. No doubt all three will get some use on the red planet.
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I strongly suspect the wind turbines will stop turning. Good grief, your Strawman army is growing rapidly. As I specifically pointed out, Wind turbines on Mars would be a practical auxiliary power source, providing power when the wind was blowing up the dust and obscuring the sunlight from the solar panels.. In addition, like most auxiliary power systems, a battery backup, a fueled generator, or a nuclear power system could be included for times when there was no sunlight or wind. There are many ways to store power, including lifting water, batteries, and flywheels.
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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau |
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Plus, having a base on the Moon is useful in and of itself.
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"If this were play'd upon a stage now, I could condemn it as an improbable fiction." Shakespeare, Twelfth Night Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor "Every book is a children's book if the kid can read." - Mitch Hedberg "Distance doesnt matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort |
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First off, unless the metal is mined, refined, and constructed there, Mars bases will not have industrial sized 100 ft+ turbines like we have here. An array of smaller sized turbines would work a whole lot better than 1 or 2 huge turbines, and be much easier to transport there. Plus, a Mars base will be built for maximum operating efficiency as possible, not like our energy gobbling systems here on Earth, so they will not need 2 megawatts of wind power to run their systems.
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I doubt that. Chances are a colony, a real colony --not a temporary space base-- will be driven by economic considerations that result in suboptimal efficiencies.
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"What you think you thought you saw you did not see." Agent J, MiB - Manhatten Bureau |
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IMO, the best role for the Moon to play in all of this is in providing processed materials for use in Earth orbit, LaGrange points, Mars orbit, and other space vehicles. The less we have to boost from Earth, the more we can explore for the same money.
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