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Hey I'm all for nuclear power, but personally I wouldn't want to drive around with radiation leaking through the back seat. I haven't studied nuclear powered rovers too much, so I might not know what I'm talking about. I just think you would have too much of a problem with radiation shielding. I mean you already have to be concerned about the cosmic radiation and occasional solar flares -- the Martian atmosphere blocks some but not all of it. Why would you want more radiation coming from your own vehicle?
"Nuclear power or fuel cells are the logical power plants..."
What about internal combustion? Fuel cells are nice but combustion is much more powerful -- something like 50 times more power per kg. Why do engineers that make things for space automatically discount "old technology"? For example: if you had two bases a couple hundred miles apart you could lay some rail between them and use a silane powered steam locomotive. Silane burns in CO2. Old technology isn't cool but it works.
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For example: if you had two bases a couple hundred miles apart you could lay some rail between them and use a silane powered steam locomotive. Silane burns in CO2. Old technology isn't cool but it works.
Combustion may be more useful on Mars for cars, but I would without question use maglev for rail systems. It is far too hard to lay down new, improved rail lines later, whereas replacing car engines isn't as hard.
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Hey I'm all for nuclear power, but personally I wouldn't want to drive around with radiation leaking through the back seat.
*Aw c'mon...don't be a party pooper, MarsGuy. You wouldn't want to be a glow-in-the-dark astronaut? Sheesh.
--Cindy
We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...
--John Sladek (The New Apocrypha)
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You can get the benefit of nuclear without the radiation if you mounted the reactor on a separate vehicle or on a trailer. If the pressurized rover with the crew had a bulldozer blade that cleared a dirt track as it moved forward, most of the time a computer-driven rover (with the nuclear reactor on board) could follow a half kilometer behind, using terrain recognition software to recognize the dirt track cleared by the bulldozer blade. If the rover with the reactor couldn't find the dirt track, someone could take over and drive it remotely from the pressurized rover. The reactor, meanwhile, would be making methane and oxygen from atmospheric CO2 and from exhaust water. Once a day or two the pressurized rover would approach, drop off its water, and fill up, running itself off the methane and oxygen in between. That way the reactor would always be available, but not a source of radioactivity.
Alternatively, you could mount the reactor in your manned vehicle, but I suspect radiation shielding would add a lot of mass.
-- RobS
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The mobile ISPP might not be a bad idea.
I see most nuke powered vehicles being of the "truck" variety, designed to follow set paths and transport bulky materials from site to site (water to base from the polar caps). the vehicles would only aproach manned bases at predetermined times so base personel can limit exposure to the limited radiation that would be produced by such a machine.
For rad shielding, a sheet metal box can be incorperated into the vehicles, either between the reactor and crew area or completely surrounding the reactor. The boxes would be filled with sifted regolith on arrival and provide the same shielding that a solid shield imported from earth would while saveing on transport mass.
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The other thought would be battery technology, a small two or four person All-terrain rover on mars would not be that heavy. You could run a rover with probably a very nice range from a nuclear powered charging station. If the vehicle is going to be using a nuclear power source, I doubt it would be large enough to warrant a huge amount of shielding. I doubt 40 hp at the wheels would require a huge power requirement. consider the Martian G. I doubt much more then 100 bhp and 100 lb.ft of torque would be required. The reactor for that would be pretty small and the shielding required would fit in a nice package.
We are only limited by our Will and our Imagination.
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Electrolysis. Clean burning and the exhaust is water which could be recycled as drinking water. The vehicle would have to stay within range of the hydrogen supply but on the up side it could share the same reactor the colony uses for electricity.
Well, if it captured it's exhaust, and had a solar cell on it, couldn't it also be able to perform electrolysis on that in case of emergencies, ie ran out of fuel, camp for a bit and let it build up more fuel, or need more oxygen for the crew. Just a thought.
We are only limited by our Will and our Imagination.
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I suspect a manned vehicle would have solar panels on the roof for an emergency, but they probably would generate barely enough power to run life support. A square meter gets about 500 watts of sunlight falling on it at high noon, and with 30% efficient solar panels that's only 150 watts per square meter. If you take into effect the sun angle and nighttime, I think you divide that number by pi, basically, so you're talking about 50 continuous watts per square meter (or multiply by 24 and you're talking about 1.2 kilowatt-hours per square meter per day). If the rover needs 2 continuous kilowatts to run life support (48 kilowatt-hours per day), it would need 40 square meters of solar arrays, which is 6.5 meters (21 feet) square. Pretty big, for a mobile vehicle!
But the vehicle could also carry panels to set on the ground in an emergency to charge up batteries or fuel cells, then you'd pack them up and drive until the surplus was gone, and then deploy them again. If you figure cells mass 5 kg per square meter and you can carry 500 kilos of cells, that's 100 square meters, good for 5 continuous kilowatts (120 kilowatt-hours per day). If life support needs 48 kilowatt-hours per day, that leaves 72 kilowatt-hours for driving. You wouldn't be able to go very far or very fast, but in an emergency it might be good enough.
-- RobS
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great idea, but isn't it a little overkill? It is a waste of techology in my view, unless the truck is being used day in and day out, for exstensive peroids of time. . .but the suspension would go out eventually, long before the reactor
"I am the spritual son of Abraham, I fear no man and no man controls my destiny"
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