Okay. So, once we are on Mars, we know basically what we need to do. Set up electromagnetic deflectors, build glass domes with anti-UV coatings, fertilize and compost like there's no tomorrow, live in caves until we can build some apartment buildings that spin to roughly simulate gravity, set up nuclear reactors (hopefully the less messy, fusion kind), distill and heat and pressurize ourselves an atmosphere, bring some farmers along, and set up shop. But, one thing we haven't talked about is how to actually get there.
Until now, in my blog, I've been assuming that I'm dictator of the United States, and I can with a word allocate a trillion dollars of American resources to the greatest project in the history of mankind. I've been acting as if money was no object. However, as anyone who even slightly follows American politics can tell you, money is very much an object. The whole presidential election this year seems to be centered on how to fix the budget crisis without ruining the economy or selling our souls to China. So, what is the cheapest, most efficient way to get out of this world?
First, we should look at our options. And our first option is the old standard: liquid hydrogen and liquid oxygen bi-propellant rockets. These have a very high efficiency and specific impulse (about 455, which is excellent), and since it is stored cold, it can be used to cool the engines before fueling them. Plus, the reaction product is just water, so there is no notable pollution from this type of rocket. There are issues, however, and the most important is thrust to weight ration. Hydrogen is the lightest element, which is good in that exhaust pressure is based on the number of molecules shot out, and that high pressure usually means increased exhaust velocity, and therefore a faster spaceship. However, the downside of lightweight fuel is that force is mass*velocity, so while velocity is high, mass is low, and the thrust to weight ratio is not the best. Also, with liquid propellants one needs to have a lot of pumps and tanks and accouterments, all of which are heavy. Still, of all rocket fuels, this is probably the best all-around fuel that exists, and it is used in the majority of launches currently. Other fuels tend to come with either many more problems or much less power. It's cheap-ish already, and since we can make it from water via electrolysis, and we have oceans full of water, it's not like we will run out any time soon.
The real problem with chemical rockets, though, is that they don't have enough power. One ends up spending a lot of fuel to carry other fuel. For example, with the Saturn V rocket, the biggest, most powerful rocket built to date, over 95% of the liftoff mass was fuel, entirely burned away. At liftoff, it weighed 2.8 million kilos, but could only carry 45000 kilos to lunar orbit, and what came back was a tiny little pod! This is the reason for stages on rockets: any weight you can get rid of during flight is weight your engines don't have to push anymore, which improves efficiency. It's actually cheaper to throw away rocket parts than to keep them on the ship!
So, what we really need is something that explodes so powerfully that we only need to run the engines for a minute or two before you are in orbit. What's the most powerful explosion you can think of? A nuclear bomb, perhaps? Try 50 of them. The principle behind nuclear pulse propulsion is simple: build a rocket with an explosion catcher on the back end, drop a nuke behind it every few seconds, and ride the shock waves into space. This may seem crazy, but in terms of thrust to weight ratio and required fuel supply this is probably the most efficient imaginable way to shoot something into space. The concept has been around since the 1950s project Orion, but was never carried to the test phase, because, well, it is a pretty hard sell. (Okay, here's what we'll do: we'll put you into a rocket, and then explode the most powerful weapon ever created by man right underneath you....What? You don't want to go?) After the 60s, nuclear treaties prohibited the use of nuclear explosives above ground, effectively making these rockets illegal. But, with a potential specific impulse of 6000, there are some who want to bring them back.
The downsides are the (obvious) danger, the expense of weapons-grade fissile material, and the fact that it will shower the radiation of fifty nuclear bombs down onto the populace every time the system is used. The last is the reason I don't much favor this idea; it's not much use colonizing a new world if in the process we ruin the one we have.
What other options are there? Well, there's space elevators, but honestly, I consider those to be a pipe dream. The mechanics work fine, and the physics is sound, but what do you make it out of? The current hopefuls are carbon nanotubes, and graphene ribbons, which can reach the required strength to support their own weight, but have never been made more than a few centimeters long before microscopic imperfections drastically reduce strength causing failure. If we can get from a few centimeters to 50000 kilometers, then it can work, but will still be almost as expensive as using rockets, in addition to being very vulnerable to space debris and meteoroids that orbit outside the atmosphere, and the fact that people on the elevator move SLOW. This will limit daily freight to orbit, and also means that people spend a lot of time in the Van Allen radiation belts, which is dangerous.
Most options that intend to solve these problems do so by creating even more unrealistic technologies, like a fountain of pellets being constantly fired into space, on which we could hitch a ride. Or, an ultra fast mag-lev train 2000 km long made of an iron tube in a sheath that hovers 80 km up in the air, and jumps the tracks when it gets going fast enough (actually, the physics for the hovering part is not the (main) problem, rather the energy supply: it takes a LOT, and if it ever turns off, 2000 km of iron bar will fall from 80 km up, and crush things.).
One idea that I like is basically to shoot stuff into space using really big guns, especially rail guns. The main problems here are air resistance and g-force. To shoot something reasonably aerodynamic into space, we need to get it up to 9 or 10 km/s ( 1.2 km/s higher than actual orbital velocity) to overcome drag. To put it in perspective, if we accelerate that much in one second, we undergo about 1000 Gs of force, which will turn a human body to pulp, and we'll need a rail gun 5 km long. This could be useful for solid freight, but anything with any empty space in it, like a lung, or a computer, would be obliterated. Let's go for a much more gentle 5 Gs. At 5 Gs, most humans will feel terrible, but they will live, and not suffer any lasting damage (For comparison, the most Gs on any roller coaster is 4.5 and only for a few instants). To reach the same speed at 5 Gs will take 200 seconds, and require a launch tube (hardly a gun at this point) 1000 km long (200 sec, average speed 5 km/s, 200*5=1000km), which, by the end, is at an angle of roughly 60 degrees. The cars will need their own rockets to direct themselves into a stable orbit after leaving the atmosphere, but fuel requirements would be minimal.
The gradient would need to be slow, or the curve upward will increase the G force to deadly levels, meaning that we are looking at a structure that starts deep underground and shoots out of a mountaintop. To be efficient, the underground tube will need to be a vacuum, so that air resistance doesn't get in the way of acceleration, and the best place to put it is on the equator, from west to east. Best place to build such a thing, then, is either Mt. Kenya in Kenya, or Kilimanjaro in Tanzania. I favor Kenya for the relative political stability, and the fact that it is almost exactly on the equator, but Kilimanjaro is taller by about 700 meters, and the track could run nearly straight beneath the Serengeti plain for the full length, while in Kenya it would have to curve to avoid starting beneath Lake Victoria. In both places, there are nature and wildlife concerns to be considered, but since the track would be very deep underground (at least 1000 meters), and the exit at an altitude where nearly nothing lives, and the power supply is 100% electric (read: we only need to pollute if we want to), I think that the benefit to humanity, along with the boon to the local economy, will outweigh the potential damage to nature.
However, after launch, we run into that air drag problem in a different way. 10 km/s is about Mach 30. That's so fast that the cars would probably hit the air at the end of the tube like a wall. They might be built to withstand the hit, or be sufficiently aerodynamic that the impact will be minimal, but with aerodynamic shapes, friction heating will become a major problem. Oddly, blunt surfaces are better at heat elimination, because they can make an air buffer that sends the heat around the ship rather than through it, while aerodynamic designs capture heat on the leading edges, destroying the structure. However, a blunt car will need to go faster to escape the atmosphere, which means a longer track, more energy, and more friction which will probably eliminate the benefit. So, the trick is to design a launch vehicle that can withstand the heat of 20 seconds in atmosphere, without being blown to bits. One way is ablative coatings; basically, you coat the ship with hundreds of thin layers of something that will melt off while in flight, carrying heat away with them. If this could ablative coating could be painted on, then the launch vehicles could be reused; just repaint them after they come down. The other way is heat shielding like on the shuttles, but those ceramics are brittle, and I would be worried that impact with the air would shatter them, leading to catastrophic failure and death. All you need is 20 seconds; after that, the car would be 120 km up or so, and outside the meaningful atmosphere, at which point the ship starts its on board thrusters.
But, all of that is a pipe dream. Realistically speaking, a Mars colony in the next thirty years will use our current hydrogen-oxygen bi-propellant systems. There's simply no way we can build anything else to do the job faster than that. And, really, the limiting factors on rockets to present have been lack of demand that would make mass production sensible, because only NASA and satellite TV companies buy them. If we decide to make space a real industry, not just a research project, then the costs will fall greatly, as they always do with mass production. The kilogram cost to orbit is already down beneath $2500 for certain rockets, thanks to private space industry like SpaceX, where when it was just NASA, the price was over $10000/kg payload. At $2500/kg, a trillion dollars will get us 400 million kilos into orbit. If we subtract the cost of building whatever it is we send (say, 250 billion), then we should say 3/4th of that. 300 million kilos.... That's about the weight of a large skyscraper, which usually costs a lot less than 250 billion, but this one will need a lot of technology packed on board.
So. 300 million kilos (assuming that prices don't go down, which, realistically, they will). Tune in next time to talk about a few of the things that will make up that weight!
Sunday, October 21, 2012
Tuesday, October 9, 2012
Farming on Mars
Who are the most important people in the world? What industry is the one industry upon whose back rests all of civilization?
Think about it: if we got rid of all computer developers, what would happen? The internet would fail. Technology would regress to the level of perhaps the 1960s or 1970s. But, we would still be able to live relatively normal lives, just with snail mail and rotary phones rather than email and smart everything. How about if we get rid of all electricians? Things regress rather further. Gas becomes really important. We start living by the sun again rather than flipping switches to stay up in the dark of night. But, suppose we get rid of all the farmers? Civilization collapses. Billions starve. Thousands of species go extinct as desperate humans try to find anything remotely edible for dinner. Nearly all technology regresses out of existence, since we no longer have time to maintain any of it, because we are too busy trying to find food.
So, farming is important. It is even more important on Mars, where there are (we presume) literally zero natural food sources. If we can't farm on Mars, we can never make the planet self sufficient. If we can't be self sufficient, then why go? It will always be prohibitively expensive to ship food from Earth, and what if we miss a shipment? The colony starves to death. Even if we did feed Mars Berlin Airlift style, we would only guarantee that the colony could never grow freely, and the main point of going to Mars is to achieve Earth independence for mankind. Basically, this is absolutely necessary. Farming on Mars must work.
But, can it work? On Earth, we have a billion years of life forms growing and decaying and growing again, all piled up in a rich, glorious, life-giving layer of sediment called topsoil, which provides plants with pretty much anything they need to grow. But, on Mars, this nutrient layer is completely nonexistent. The soil composition of Mars is hard to tell precisely; we honestly don't know very well what it is like. The satellites, of course, can use infrared and gamma imaging to detect precise chemical compositions, but these only function to a maximum depth of a couple millimeters for infrared, or a few centimeters, for gamma. So, we can talk about topsoil, but not about anything deeper than about the length of your hand. We can guess our way deeper than that by looking at craters, where a lot of digging has been done for us, but wherever there are no craters, we have no information.
The good news is that in most areas the soil seems pretty similar to Earth. There's more iron, and less water and nitrogen, but they are all present. The Ph results have been inconclusive, but most figures seem to be mildly alkaline, leading to a variety of carbonate minerals that will help plant growth. Really, all the stuff for growing exists already, except any sort of fertilizer. Now, I'm neither a geologist nor a farmer, and the articles I read on this matter were admittedly a little beyond the scope of my knowledge, but as far as I understood them, the prognosis for farming is actually good.
The colonists will also have some advantages. All irrigation will be mechanized, and all habitat precisely controlled, so the growing conditions in terms of temperature, rainfall, and whatnot should all be optimal. Furthermore, since we will be mixing our own atmosphere, and since CO2 is the main component of martian air, we can easily optimize the CO2 level for plant growth (roughly 2% is what plants like best, which is substantially more than Earth atmospheric levels, but still quite comfortable for human breathing). Most of all, as long as we are selective about the bacteria and fungi we bring to Mars, we can set up an ecosystem that has no plant diseases for the first few decades, and once multiple colony domes are established, the isolated nature of each settlement will protect neighboring food supplies from any blights that might occur locally. Unlike humans, Martian crops will never ask to go on vacation to Earth, so they probably won't need to update their immune systems as often as we do (though it would be wise to breed disease resistant strains just in case), and intentional exposure will not be important. No "Disease Day" for plants.
The bad news is that sun intensity ranges from half to about one third of the light on Earth, there are sometimes global dust storms which block the sun for days, and we'll be starting from zero in terms of any biological components of soil. That zero start point cannot be stressed enough; the other problems may mean slower growing and occasional difficulties, but they can be solved with sun lamps. Easy. Meanwhile, getting fertile soil requires coordinated colony-wide efforts from day one onward into eternity, or it will simply not work. It will be like trying to grow plants on unfertilized sand, which as any gardener knows, is exceedingly difficult. Even though the necessary chemical ingredients are present, they may not be easily accessible to a growing plant. Furthermore, the stakes are very, very high: if the plants don't grow, at least fifty people starve (hopefully more like a thousand), and the world loses about a trillion dollars worth of invested capital. So, it is important to get it right.
There are two ways to deal with this. The first is using every bit of human, animal, food, and biodegradable waste as fertilizer, right from the start. We'll need to get over our qualms and pour our sewage on our farms to help get things going. This will help create a closed loop for existing biological material to be recycled. We'll want to lay a sort of underground "floor" to trap irrigation water, and prevent valuable bacteria from leaching into the rocks below, where plants can't reach them. As we develop the soil more and more, we can expand and add local resources to our loop to make it wider.
The second thing we can do is hunt on Earth for forms of bacteria that eat rocks. These creatures, called lithotrophs, are some of the most primitive life forms on Earth, using neither any other living thing, nor the excretions of any other living thing, to survive. Fortunately, they are quite common even today. Unfortunately, most of them secrete chemicals that are not very useful for improving soil quality, such as sulpheric acid. However, if we can find the right sort that will take the soil chemistry of Mars and turn it into something useful, we can seed them onto Mars in domes that are set up by robots before we arrive. With no predators or competitors, they should thrive, eat lots of rocks, die, and enrich the soil for us. The advantage is that the colonists will land with a ready made dome already on the ground, complete with breathable air, temperature control, and a primitive sort of topsoil for farming. The disadvantage is that to do this, we must first invent the robot that can build the dome, and it means at least two flights out instead of one.
Normally, I prefer not to recommend inventing something in order to solve a problem, because inventions usually happen in their own time rather than when you want them to, and cost a lot more money than simply changing existing technology to suit your needs. But, given the supreme importance of this aspect of Martian colonization, in this case I think it would be foolish not to give ourselves every possible advantage, and plan for every possible contingency. If the farmers fail, then everybody dies. Seems they had best not fail.
Now, all of this says nothing about the difficulties that might be inherent in low gravity farming because really these problems are minimal. Gravity is necessary for plants to develop strong root structures, but the amount required seems to be pretty small; microgravity, in theory, is sufficient. The main thing is that the dirt needs to be compacted enough for the roots to grab on to, and hold the plants upright. However, this really isn't a major problem, as it turns out; we've been growing plants in zero gravity in space for a while now. In fact, the Russians grew wheat all the way back on old space station Mir.
There are the BASICS of farming on Mars. I didn't delve deeply into soil chemistry, so this topic may arise again later, but for now, this will have to suffice. Final summation: doable, but difficult. To hedge our bets, we can invent robots that build domes without us, and start biological processes before we arrive. Otherwise, our best bet is to spend a few billion dollars to send a few tons of this along on the colony ship:
Think about it: if we got rid of all computer developers, what would happen? The internet would fail. Technology would regress to the level of perhaps the 1960s or 1970s. But, we would still be able to live relatively normal lives, just with snail mail and rotary phones rather than email and smart everything. How about if we get rid of all electricians? Things regress rather further. Gas becomes really important. We start living by the sun again rather than flipping switches to stay up in the dark of night. But, suppose we get rid of all the farmers? Civilization collapses. Billions starve. Thousands of species go extinct as desperate humans try to find anything remotely edible for dinner. Nearly all technology regresses out of existence, since we no longer have time to maintain any of it, because we are too busy trying to find food.
So, farming is important. It is even more important on Mars, where there are (we presume) literally zero natural food sources. If we can't farm on Mars, we can never make the planet self sufficient. If we can't be self sufficient, then why go? It will always be prohibitively expensive to ship food from Earth, and what if we miss a shipment? The colony starves to death. Even if we did feed Mars Berlin Airlift style, we would only guarantee that the colony could never grow freely, and the main point of going to Mars is to achieve Earth independence for mankind. Basically, this is absolutely necessary. Farming on Mars must work.
But, can it work? On Earth, we have a billion years of life forms growing and decaying and growing again, all piled up in a rich, glorious, life-giving layer of sediment called topsoil, which provides plants with pretty much anything they need to grow. But, on Mars, this nutrient layer is completely nonexistent. The soil composition of Mars is hard to tell precisely; we honestly don't know very well what it is like. The satellites, of course, can use infrared and gamma imaging to detect precise chemical compositions, but these only function to a maximum depth of a couple millimeters for infrared, or a few centimeters, for gamma. So, we can talk about topsoil, but not about anything deeper than about the length of your hand. We can guess our way deeper than that by looking at craters, where a lot of digging has been done for us, but wherever there are no craters, we have no information.
The good news is that in most areas the soil seems pretty similar to Earth. There's more iron, and less water and nitrogen, but they are all present. The Ph results have been inconclusive, but most figures seem to be mildly alkaline, leading to a variety of carbonate minerals that will help plant growth. Really, all the stuff for growing exists already, except any sort of fertilizer. Now, I'm neither a geologist nor a farmer, and the articles I read on this matter were admittedly a little beyond the scope of my knowledge, but as far as I understood them, the prognosis for farming is actually good.
The colonists will also have some advantages. All irrigation will be mechanized, and all habitat precisely controlled, so the growing conditions in terms of temperature, rainfall, and whatnot should all be optimal. Furthermore, since we will be mixing our own atmosphere, and since CO2 is the main component of martian air, we can easily optimize the CO2 level for plant growth (roughly 2% is what plants like best, which is substantially more than Earth atmospheric levels, but still quite comfortable for human breathing). Most of all, as long as we are selective about the bacteria and fungi we bring to Mars, we can set up an ecosystem that has no plant diseases for the first few decades, and once multiple colony domes are established, the isolated nature of each settlement will protect neighboring food supplies from any blights that might occur locally. Unlike humans, Martian crops will never ask to go on vacation to Earth, so they probably won't need to update their immune systems as often as we do (though it would be wise to breed disease resistant strains just in case), and intentional exposure will not be important. No "Disease Day" for plants.
The bad news is that sun intensity ranges from half to about one third of the light on Earth, there are sometimes global dust storms which block the sun for days, and we'll be starting from zero in terms of any biological components of soil. That zero start point cannot be stressed enough; the other problems may mean slower growing and occasional difficulties, but they can be solved with sun lamps. Easy. Meanwhile, getting fertile soil requires coordinated colony-wide efforts from day one onward into eternity, or it will simply not work. It will be like trying to grow plants on unfertilized sand, which as any gardener knows, is exceedingly difficult. Even though the necessary chemical ingredients are present, they may not be easily accessible to a growing plant. Furthermore, the stakes are very, very high: if the plants don't grow, at least fifty people starve (hopefully more like a thousand), and the world loses about a trillion dollars worth of invested capital. So, it is important to get it right.
There are two ways to deal with this. The first is using every bit of human, animal, food, and biodegradable waste as fertilizer, right from the start. We'll need to get over our qualms and pour our sewage on our farms to help get things going. This will help create a closed loop for existing biological material to be recycled. We'll want to lay a sort of underground "floor" to trap irrigation water, and prevent valuable bacteria from leaching into the rocks below, where plants can't reach them. As we develop the soil more and more, we can expand and add local resources to our loop to make it wider.
The second thing we can do is hunt on Earth for forms of bacteria that eat rocks. These creatures, called lithotrophs, are some of the most primitive life forms on Earth, using neither any other living thing, nor the excretions of any other living thing, to survive. Fortunately, they are quite common even today. Unfortunately, most of them secrete chemicals that are not very useful for improving soil quality, such as sulpheric acid. However, if we can find the right sort that will take the soil chemistry of Mars and turn it into something useful, we can seed them onto Mars in domes that are set up by robots before we arrive. With no predators or competitors, they should thrive, eat lots of rocks, die, and enrich the soil for us. The advantage is that the colonists will land with a ready made dome already on the ground, complete with breathable air, temperature control, and a primitive sort of topsoil for farming. The disadvantage is that to do this, we must first invent the robot that can build the dome, and it means at least two flights out instead of one.
Normally, I prefer not to recommend inventing something in order to solve a problem, because inventions usually happen in their own time rather than when you want them to, and cost a lot more money than simply changing existing technology to suit your needs. But, given the supreme importance of this aspect of Martian colonization, in this case I think it would be foolish not to give ourselves every possible advantage, and plan for every possible contingency. If the farmers fail, then everybody dies. Seems they had best not fail.
Now, all of this says nothing about the difficulties that might be inherent in low gravity farming because really these problems are minimal. Gravity is necessary for plants to develop strong root structures, but the amount required seems to be pretty small; microgravity, in theory, is sufficient. The main thing is that the dirt needs to be compacted enough for the roots to grab on to, and hold the plants upright. However, this really isn't a major problem, as it turns out; we've been growing plants in zero gravity in space for a while now. In fact, the Russians grew wheat all the way back on old space station Mir.
There are the BASICS of farming on Mars. I didn't delve deeply into soil chemistry, so this topic may arise again later, but for now, this will have to suffice. Final summation: doable, but difficult. To hedge our bets, we can invent robots that build domes without us, and start biological processes before we arrive. Otherwise, our best bet is to spend a few billion dollars to send a few tons of this along on the colony ship:
Sunday, August 19, 2012
Quantum Conundrums
I have been absent for the past two weekends, as a few of you may have noticed. There was a pretty good reason: my internet has been out of order for a while, and getting new internet as a foreigner in Korea leads to several roadblocks, such as the fact that I will only stay six more months, but all the contracts are for two years or more. So, that's a tidbit from my life. However, as of now, my internet is back, and I can write and research as before, so look for weekly updates again.
Now, speaking of telecommunication problems, how will communications on Mars work? Well, I should be more specific: How will communication to and from Mars work? If you have been paying any attention to the Mars Curiosity rover story, you will know that there was a lot of tension about the landing because of the fact that the landing needed to be fully automated. This was because of a signal delay of fourteen minutes between Earth and Mars, which is the problem I will be trying to overcome today.
Now, before we even get started, we should pause a moment and simply consider how very, very far away Mars is. Mars is so far away that it will take fourteen minutes to reach at light speed! Actually, since Mars orbits differently from Earth, the real distance varies between about four light minutes to twenty-one light minutes, and fourteen is merely the current figure, roughly 252 million kilometers. Anyway, we're talking about really, really far.
Okay, now that our minds are done being blown at the distance, let's think about this problem. First, I want to point out that it isn't really a very big problem. A Mars colony will have people on the ground, so the issues we are seeing with a fourteen minute delay in problem solving for the Curiosity will not exist; people will be on hand to solve issues that arise immediately. A mission of the magnitude I am envisioning will include all the experts required to handle any situation that comes up. Once the colonists arrive, they should be self sufficient, and not rely on Earth for anything, since no matter how fast an SOS gets to Earth, the homeworld won't be able to send help for six months minimum.
Furthermore, even with a fourteen minute delay, we can still communicate with home, send messages that say “I miss you!” or “Mars is awesome, come visit!” Emails are still easy, just, instead of taking less than one second to be delivered, they will take fourteen minutes. Humanity survived for thousands of years before lightspeed communications, and slowing down by a few minutes will not hurt anyone.
However, a lot of our conveniences are tied to very fast communications. The biggest one is the internet; whenever you want to open a web page, a signal goes to the server that hosts it, tells the server to send you information, and then comes back with the information you requested. On Earth, all of this usually takes less than a second. On Mars, it would be a half hour back and forth, meaning you click a link, go make a pot of coffee, watch an episode of Arrested Development or some other TV show, and then come back and your page has loaded. Any interaction with the page would take equally long. It would be like stepping back into the worst parts of the dial up era.
This would not have bothered us before the 1990's, but now, life without high speed internet seems practically impossible. As one who has been living with no internet for the last week and a half, I can attest that really, this isn't the case; life goes on. But, I said in my first post that I plan to spend a trillion US tax dollars building this city on Mars, and at a price tag like that, I would hope that my colonists can at least video chat with their relatives back home. So how can we do it?
Well, lightspeed is pretty much as fast as it gets in terms of actually moving one thing to another place. In fact, we believe it is physically impossible for anything to move faster than light, because to do so would violate causality, and make it look like the effect of something happened before the thing even got there. For example, if a faster than light spaceship hit a planet, we would not see it until after it hit. Then, we would see the light that it had reflected just before it hit, then a little earlier, and so on, so that to an observer on the planet, the ship didn't hit at all; a crater formed, and then a ship shot out of it backwards into space. The ship would be moving backward in time, but the crater would be moving forward. Of course, at lightspeed the ship's mass would also be infinite, so really the whole planet would be obliterated by the impact if this sort of thing happened. Fortunately, we believe that it's impossible.
So where does that leave our communication problem? Seems like a dead end, but there is actually one way around this rule: Quantum teleportation. No, this is not like “beam me up, Scotty!” at all. What happens is this: two tiny quantum particles can be made to interact in such a way that they become “entangled,” which means that they share the same quantum state as one another, even if they are moved apart. Then, we can move the two particles apart to any distance, it doesn't really matter how far. So far, the most we've managed is a couple hundred kilometers, for reasons I'll talk about later. Finally, we can make the particle at one end switch quantum states, and then the other will switch on its own, instantaneously. This switch can be used to represent a bit of data, a 1 or a 0, and voila, instantaneous digital communication.
This doesn't violate causality, because the entangled particles were moved apart at sub-light speeds, which apparently means that they are causally linked; they share the same light cone. Now I don't claim to understand why that makes any difference, since it seems that doing this instantaneous communication would break the old causal links, and make a new light cone of its own, but it's been tested experimentally, and it does in fact work. So, who cares why? Physicists can figure that out later.
Now there are several ways that this is good. First, if we can mass produce it, you can play streaming video and multiplayer videogames from Mars on Earth servers with zero latency. Second, it solves the problem of communicating while Earth and Mars are on opposite sides of the sun (We can't send radio signals through the Sun, because the Sun emits full spectrum radiation, but quantum communication doesn't rely on sending anything, so the sun won't matter), meaning you don't need to worry about putting long range communication satellites at various Earth and Mars orbital Lagrangian points (although, I would build space stations there anyway, just because, well, why not?). And best of all, this technology or something like it is a major step toward the next big computer revolution, which is quantum computing.
But, making a machine that actually does this is INCREDIBLY hard. There are many reasons why, but the most obvious is that once two particles are entangled, they can very easily become disentangled if they touch well, basically anything. Which is problematic, because we need to move one end of the string to Mars, and how do you move something without touching it? Very carefully, usually with magnetic fields. Even then, it doesn't work very well, which is why we've only managed a couple hundred kilometers so far.
Second, quantum particles are really, really small, which makes detecting their state and changes in their state extremely difficult, again, without touching them. Also, this small size makes them very easy to lose (Where did I put that one quark I had.... Oh, somewhere in this pile of 2,000,000,000,000,000,000,000,000,000 other quarks.... Great...). Scientists at present can do all of this stuff, but inconsistently and not very well (10% efficiency is something to celebrate). We don't have the same level of control as we do at the atomic level, because at the quantum level everything is based on probability, which means that we never even really know where the particles we are measuring are, we only know where they PROBABLY are.
So, all told, telecommunications is a problem that has a potential solution, but the solution is waiting for a major breakthrough in quantum control and manipulation before it can become a reality. How long will that take? We don't know. Will it be ready by the time I am president in 2040? Maybe. We don't know. If it's not ready, should we hold off on colonization? Absolutely not. If worse comes to worst, we can just download an imprint of the entire internet and put it on the colony ship, and run a local high speed network with updates from Earth streaming continuously once communications are set up. At least then Mars has internet, just not connected to Earth at high speeds.
All of the internet, in one ship....How many hard drives do you think that would take? Might be too big. I'll have to do some research....
Friday, July 27, 2012
Dream High
I am probably one of a very limited number of people in the world who think punning references to Korean "Glee" knockoff series with regard to space exploration are funny. We call it "Huffman Humor" around my house, and it consists of jokes that require lengthy explanations before anyone even realizes that they are jokes, and then only get pity laughs.
But, despite the pun, my topic this week is serious. In fact, it may be the most important thing I ever write on this blog. The inspiration was a documentary, or rather the kickstarter trailer of a documentary in the making, which will discuss why the US space program is in a long, terrible decline. The reality of it breaks my heart. So, I am going to take a break from my normal, lackadaisical, semi-scientific, semi-sarcastic approach, and really speak plainly. Honesty is something we don't see too often these days, and I think it is time for some.
We need hope. But right now, we do not have it.
At this moment, I am speaking of America, as an American, so for any international readers, I apologize, but this might not really pertain to you.
America needs hope. We can delude ourselves with lies about our own greatness for only so long before the delusions stop working, and we must face reality. And that reality is that we are a nation fallen from glory, a glory once undeniable, once the envy of the world, and the source of our pride as men and women. In the past, we could be proud, because we were part of something great. Now, America is not great. It's not even good, unless we are generous, or blinded to reality by the mythology we are taught our whole lives.
Honesty. I promised I would give it. So here it is: I have no patriotism for America, at least not as it is now. In fact, as recently as last week, I was considering renouncing my citizenship and immigrating to someplace else permanently. And the simple reason is that I think America is going to fail, to crash and burn because it grew too used to living rich, and forgot how to work for its money. America has forgotten the most important thing it ever knew: How to dream.
There was an America though, once, which knew how to dream, and dream big. I never experienced the 1960s and 70s, so I don't know the full depth of the fervor, the patriotism, and the true, honest belief that American hard work, innovation, and ingenuity could carry mankind off of this world. But, I have seen the look in my father's eyes, on days when he remembers it, and that is enough. From that look, I know the dreams he held. I know from his recollections of his school days how he wished to be a scientist, how as a boy he dreamed of being an astronaut. I know from the Buck Rogers stories he told me at bedtime, when I was young, that the dream of space was buried deep in him, and that it had never let go. It was a dream he passed to me, wittingly or not.
I also know he was not alone in his fervor. During the space race, millions of children wanted to learn science and engineering. Why? Not because it was important to their country, or they had good career opportunities, but because they wanted to go out into the night sky and see what was there. Kennedy's dream of landing on the moon lit a fire in the hearts and minds of the whole nation, a fire that fueled the technological advances of the next two decades, keeping America on the razor edge of advancement.
And then they reached the moon, said the immortal words "A giant leap for mankind," and etched in the memories of the world an event that would never be forgotten. We left our planet. We succeeded. Surely, nothing would prove impossible for us, and a new era would dawn. With baited breath, mankind waited for that future to come....
And it didn't. We made the giant leap, we found a cold, dead rock, and then we leapt right back again. And then, nothing. We didn't try to tame the rock, not even to live on it. After a couple short walks, we left and never returned. And that fire in the hearts and minds of America burned down, to a sizzle. In the younger generation, the fire was never planted. Instead of scientists, they became investment bankers. And slowly, we lost our technological preeminence, and our pride went from a well-earned right to stand tall amongst our fellow men to hollow platitudes.
We need that fire again. We need a project that inspires us to be better than normal human beings, that drives us, instills in us a passion and a belief in the possibility that humanity, and America, truly can be great. We need another goal, a new symbol for the strength and resilience of our people, a symbol that shines in this dark night of our country and says that even now, from the pit of our woe, we have within us the strength to touch the stars.
Mars can be that symbol. Not walking on Mars and coming back, but living on Mars. Staying there. Making Mars a place for humanity. And not just Mars, but all of space! We should be on Deimos, on Io, mining asteroids, building space stations at the opposite side of the sun from our orbit. The solar system is ours for the taking, and all we need to do is grasp it. That is a dream that people, no matter their political affiliation, can agree on. A dream to light a fire in their hearts, the way this picture did, almost half a century ago.
What stands in our way? Two things. First, money. Politicians win few votes by giving NASA money, and therefore they seldom do so. As a result, NASA gets only half a percent of our tax dollars, and still some argue it is too much in a time of economic crisis. As Neil Degrasse Tyson says in this keynote speech, there are a bunch of arguments for going to space (I talked about many of them in my first post), but they are tired and old, and people don't listen to them very well. They take more than an elevator ride to explain, and people these days therefore don't have the attention span to hear them
The second problem is the root of the first: we don't think past our own lives. As human beings, we concern ourselves with the here and now, think fuzzily a few years into the future, but past a decade we don't make any plans. That mistake leads to the argument that "There are problems on Earth. We shouldn't worry about space until those problems are solved." Why not? The fact that one problem exists doesn't mean we shouldn't solve another. Humanity needs to become a planning species, a species that controls their own fate, homo evolutis, the human that determines the next step in his own evolution.
Is this happening? Slowly. We have the environmental movement. We have people realizing that the actions of the last hundred years are going to drastically affect the realities of the next hundred. People are starting to see the need to be careful about long term effects. But with regard to space, people aren't thinking of it as the excellent investment that it is, they are thinking of it as a waste. Politicians are mocked for suggesting that we can live on the moon, when we could have done it twenty years ago if we wanted. Government in the USA deprioritizes the space program. The shuttles are gone. The budget gets cut as costs increase. People are still more concerned with the here and now than what the future will hold, when the fact is that the current here and now was determined twenty years ago by the way people then thought about (or didn't think about) the future.
The same will be true as time goes on. We can't fix the present, because the present is an effect of the past. So we should stop trying. What we can do is fix the future. Our decisions now will affect the fate of humanity for millions of years, which is a great responsibility. Will they look back on us as uncivilized fools who didn't even know enough to plan a century in advance? Will they look back on us as the technologically stagnant era of man between our initial forays into space and the beginning of widespread colonization? Or will they not exist to look back at all, because we did not build a place for them to survive if Earth dies?
Not if I can help it.
But, despite the pun, my topic this week is serious. In fact, it may be the most important thing I ever write on this blog. The inspiration was a documentary, or rather the kickstarter trailer of a documentary in the making, which will discuss why the US space program is in a long, terrible decline. The reality of it breaks my heart. So, I am going to take a break from my normal, lackadaisical, semi-scientific, semi-sarcastic approach, and really speak plainly. Honesty is something we don't see too often these days, and I think it is time for some.
We need hope. But right now, we do not have it.
At this moment, I am speaking of America, as an American, so for any international readers, I apologize, but this might not really pertain to you.
America needs hope. We can delude ourselves with lies about our own greatness for only so long before the delusions stop working, and we must face reality. And that reality is that we are a nation fallen from glory, a glory once undeniable, once the envy of the world, and the source of our pride as men and women. In the past, we could be proud, because we were part of something great. Now, America is not great. It's not even good, unless we are generous, or blinded to reality by the mythology we are taught our whole lives.
Honesty. I promised I would give it. So here it is: I have no patriotism for America, at least not as it is now. In fact, as recently as last week, I was considering renouncing my citizenship and immigrating to someplace else permanently. And the simple reason is that I think America is going to fail, to crash and burn because it grew too used to living rich, and forgot how to work for its money. America has forgotten the most important thing it ever knew: How to dream.
There was an America though, once, which knew how to dream, and dream big. I never experienced the 1960s and 70s, so I don't know the full depth of the fervor, the patriotism, and the true, honest belief that American hard work, innovation, and ingenuity could carry mankind off of this world. But, I have seen the look in my father's eyes, on days when he remembers it, and that is enough. From that look, I know the dreams he held. I know from his recollections of his school days how he wished to be a scientist, how as a boy he dreamed of being an astronaut. I know from the Buck Rogers stories he told me at bedtime, when I was young, that the dream of space was buried deep in him, and that it had never let go. It was a dream he passed to me, wittingly or not.
I also know he was not alone in his fervor. During the space race, millions of children wanted to learn science and engineering. Why? Not because it was important to their country, or they had good career opportunities, but because they wanted to go out into the night sky and see what was there. Kennedy's dream of landing on the moon lit a fire in the hearts and minds of the whole nation, a fire that fueled the technological advances of the next two decades, keeping America on the razor edge of advancement.
And then they reached the moon, said the immortal words "A giant leap for mankind," and etched in the memories of the world an event that would never be forgotten. We left our planet. We succeeded. Surely, nothing would prove impossible for us, and a new era would dawn. With baited breath, mankind waited for that future to come....
And it didn't. We made the giant leap, we found a cold, dead rock, and then we leapt right back again. And then, nothing. We didn't try to tame the rock, not even to live on it. After a couple short walks, we left and never returned. And that fire in the hearts and minds of America burned down, to a sizzle. In the younger generation, the fire was never planted. Instead of scientists, they became investment bankers. And slowly, we lost our technological preeminence, and our pride went from a well-earned right to stand tall amongst our fellow men to hollow platitudes.
We need that fire again. We need a project that inspires us to be better than normal human beings, that drives us, instills in us a passion and a belief in the possibility that humanity, and America, truly can be great. We need another goal, a new symbol for the strength and resilience of our people, a symbol that shines in this dark night of our country and says that even now, from the pit of our woe, we have within us the strength to touch the stars.
Mars can be that symbol. Not walking on Mars and coming back, but living on Mars. Staying there. Making Mars a place for humanity. And not just Mars, but all of space! We should be on Deimos, on Io, mining asteroids, building space stations at the opposite side of the sun from our orbit. The solar system is ours for the taking, and all we need to do is grasp it. That is a dream that people, no matter their political affiliation, can agree on. A dream to light a fire in their hearts, the way this picture did, almost half a century ago.
What stands in our way? Two things. First, money. Politicians win few votes by giving NASA money, and therefore they seldom do so. As a result, NASA gets only half a percent of our tax dollars, and still some argue it is too much in a time of economic crisis. As Neil Degrasse Tyson says in this keynote speech, there are a bunch of arguments for going to space (I talked about many of them in my first post), but they are tired and old, and people don't listen to them very well. They take more than an elevator ride to explain, and people these days therefore don't have the attention span to hear them
The second problem is the root of the first: we don't think past our own lives. As human beings, we concern ourselves with the here and now, think fuzzily a few years into the future, but past a decade we don't make any plans. That mistake leads to the argument that "There are problems on Earth. We shouldn't worry about space until those problems are solved." Why not? The fact that one problem exists doesn't mean we shouldn't solve another. Humanity needs to become a planning species, a species that controls their own fate, homo evolutis, the human that determines the next step in his own evolution.
Is this happening? Slowly. We have the environmental movement. We have people realizing that the actions of the last hundred years are going to drastically affect the realities of the next hundred. People are starting to see the need to be careful about long term effects. But with regard to space, people aren't thinking of it as the excellent investment that it is, they are thinking of it as a waste. Politicians are mocked for suggesting that we can live on the moon, when we could have done it twenty years ago if we wanted. Government in the USA deprioritizes the space program. The shuttles are gone. The budget gets cut as costs increase. People are still more concerned with the here and now than what the future will hold, when the fact is that the current here and now was determined twenty years ago by the way people then thought about (or didn't think about) the future.
The same will be true as time goes on. We can't fix the present, because the present is an effect of the past. So we should stop trying. What we can do is fix the future. Our decisions now will affect the fate of humanity for millions of years, which is a great responsibility. Will they look back on us as uncivilized fools who didn't even know enough to plan a century in advance? Will they look back on us as the technologically stagnant era of man between our initial forays into space and the beginning of widespread colonization? Or will they not exist to look back at all, because we did not build a place for them to survive if Earth dies?
Not if I can help it.
Monday, July 23, 2012
Magnetic Fields and You
Magnets are cool. Seriously. They are one of the coolest things ever. You can stick them to metallic surfaces, you can make them bend electricity, you can use them to MAKE electricity, you can make them hover. If you have a round one, you can roll it down a whiteboard. Just ask any five to ten year old what the coolest thing in science is, and magnets will rank right after dinosaurs and lasers (which, let's be honest, shouldn't even be considered in the same league, they reek so thoroughly of coolness). Another cool thing about magnets: They prevent everyone on Earth from dying horribly of cancer.
Let's look at how this works. First, it should be noted that the correct answer to the question "How does Earth's magnetic field work?" is "We don't know, but we have a hunch that might be right, assuming our theories about the inner parts of the planet are correct." That hunch is as follows (according to HowStuffWorks.com here): The core of the Earth is made of super hot, super pressurized, solid crystallized iron. Outside the core, Earth's rotation causes some other, slightly less hot, slightly less pressurized, liquid molten iron to spin around the solid iron core, creating a bit electricity and thus a bit of magnetic field. I'm sure there are much more sciency explanations than this one, but that's the gist.
This magnetic field is really weak (only half a Gauss on Earth's surface, and only 1/8 of that 8000 miles up (which is the diameter of the Earth)), but still strong enough to deflect a large part of the harmful solar wind, forcing it to bend out around the Earth. Without it, solar wind would annihilate our ozone layer, expose us to the full brunt of solar radiation, and slowly strip away our atmosphere until nothing was left, a process which, on Mars, is currently in its third step.
Which leaves us with a problem. Mars has no ozone. Well, actually, that's not too big a problem; we'll be forced to live in domes anyway to trap a useful atmosphere, and the domes will need to be glass so that plants beneath them get light to grow. Fortunately, normal glass will block most UV rays on its own, and we've already invented various films and treatments (check one of them out here) that can cut out those remaining few rays and leave us safe and sunny. So, really, the ozone issue is not an issue. And, since we will be distilling our own atmosphere to fill all of these domes, an atmosphere which the sun cannot strip away, the whole solar wind stealing our air thing isn't too important either.
However, the matter of high energy cosmic rays is still a big problem. A lot of this problem will occur in space on the way to the planet, but I will deal with that in a later entry on spacecraft design. For now, I want to limit my inquiries to the colony itself. According to the Mars Radiation Environment Experiment (MARIE), radiation on the surface of Mars should be roughly equal to that on the International Space Station, at about 100-200 mSv (microSieverts) per year. To give some context, the maximum recommended lifetime dose of radiation is about 1000 mSv, which would be 10 years on Mars, not counting the radiation the first colonists would experience on the way there. Cancer risks increase by about 5.5% per Sievert, so at 1000 mSv you have a 5.5% chance, at 2000 mSv an 11% chance and so on. On Earth, we get about 0.4 mSv of cosmic radiation annually (this does not include Earth-bound radiation sources, like nuclear power plants, and bananas. Read here for more information.) So, if we want to live on Mars, chronic radiation is a problem we'll need to solve.
It gets worse. Not only is chronic radiation a possibility, but without the protection of a magnetic field, the extremely intense radiation from solar flares will hit Mars (and our poor fledgling colony) head on. Radiation during these events is sometimes over 100 times background levels. That's a ridiculous 2000 mSv per day, and sometimes these flares last a week of more! In that week, the lifetime risk of radiation induced cancer for every exposed citizen of Mars would go from 0% to 77%. A 77% chance of getting cancer. This radiation dose (.14 Gray in a week) is also high enough to cause chronic radiation syndrome, which is basically all of the nastiness that comes from working in Chernobyl on the wrong day, except drawn out over the course of a year or two. Not a pretty sight.
Okay, so things are grim. How do we fix it? Well, since things will probably take some setting up once we arrive on Mars, the first solution will probably be digging. Mass blocks radiation. Lead, as most of us know, is the best single radiation absorber, but 2 meters of dirt or stone will accomplish the same goal as eighteen centimeters of lead, and won't need to be mined carefully or processed before use. Two meters underground is almost 22 halving thicknesses of dirt, which means that if a solar flare scorches the martian soil with 2000 mSv a day for two weeks, our underground explorers will feel only 0.0005 mSv. Which is completely harmless. So, at least at first, humans can escape the radiation on Mars by building and living in caves, which also have the advantage that they do not require the humans to bring too many construction materials with them to Mars (yay saving money!).
But who wants to move to another planet just to become a cave man? Not me. I like living on the surface, and seeing the sun once in a while. Plus, plants need light to grow, and light tends to be scarce in caves. Of course we can grow our crops underground with full spectrum light bulbs, but it costs energy, energy we could get from the sun, for free, if we could keep the radiation from killing us in our pretty little domes. How can this happen? Well, we could make our own magnetic field. Some people suggest digging into the core of Mars and blasting away with nuclear weapons trying to start a dynamo effect and make a field like Earth's, but I don't buy into the idea; feels too much like Armageddon (an excellent story, but not really related to actual science). So it seems like we should make a whole lot of small magnetic deflectors. After all, it is a very weak magnetic field that repels the solar wind on Earth, right?
Wrong. The magnetic field on Earth works because it has a lot of space to work with. An average deflection of only one degree per thousand miles will mean that everything misses the whole planet if the field takes effect 25,000 miles from the surface (because the diameter of the Earth is less than 25 degrees on a circle with radius 25000 miles, so shifting radiation by 25 degrees in any direction will make it miss Earth). At that height, Earth would have a field strength of .00098 Gauss, which is very weak, but not negligible. But, we don't have the ability to make a field that big. Magnetic fields lose power as a cube of distance, meaning that if you double distance, power drops to 1/8th.
Let's take as an example the strongest electromagnet on Earth, which is 45 Tesla, or 450,000 Gauss, about 900,000 times stronger than the Earth's magnetic field at a range of 0, with a diameter of about two meters. To put that in perspective, this magnet will literally rip a pacemaker out of your heart from ten feet away.
So, how strong is it from 25000 miles away? 25000 miles is 40250 km, or 40,250,000 meters. This is very roughly 2m^26 (rounded to nearest power of 2), so the diameter of the magnet doubles 26 times to reach that distance. That means the strength would be 450000/8^26 Gauss, which leaves you with an infinitesimally small charge (1.5*10^-18 Gauss). (Note: Only the field strengths at given distances in this section are actually real values. One degree per thousand miles is a number drawn from thin air. Actual deflection is not linear, but exponential because as the beam approaches the magnet, the magnetic field gets stronger, and as the angle changes from perpendicular, it also becomes easier to change because there is less momentum fighting against the magnetic field. The energy of each radioactive particle also greatly affects how much it is swayed, and those energies vary hugely. So, these numbers are meant only as an example to illustrate the problem, not as actual mathematical solutions to it.)
A possible solution is produce a lower magnetic field, but with a much bigger radius. Suppose we built an electromagnet with a power rating of 2 Tesla, or 20000 Gauss, but a diameter of 50 miles. At 25000 miles (roughly 50*2^9), this would yield a force of .00015 Gauss, which is more than 1/6th that of Earth. So, wider magnets with smaller charges might work. If you make the magnet with superconductors, then you can run it on much less electricity, and a cooling system is a lot cheaper on a planet which is already quite cold. It would certainly cost a fortune, and take a very long time to build, probably a decade or more of concentrated effort since the crew would be so comparatively small. The thing I don't know is how much power it would take to generate a magnet like this; it could require billions of megawatts to just get the thing going. If the final power input is less than the constant several megawatts required by smaller magnets, then this sort of thing would be a worthwhile project. If the smaller magnets take less power in the long run, then they are probably the better investment, and in any case it seems likely that they will be employed as a short term solution. Whatever else is true, it looks like a good number of years on Mars before the magnetic deflector shields are fully up and running.
Let's look at how this works. First, it should be noted that the correct answer to the question "How does Earth's magnetic field work?" is "We don't know, but we have a hunch that might be right, assuming our theories about the inner parts of the planet are correct." That hunch is as follows (according to HowStuffWorks.com here): The core of the Earth is made of super hot, super pressurized, solid crystallized iron. Outside the core, Earth's rotation causes some other, slightly less hot, slightly less pressurized, liquid molten iron to spin around the solid iron core, creating a bit electricity and thus a bit of magnetic field. I'm sure there are much more sciency explanations than this one, but that's the gist.
This magnetic field is really weak (only half a Gauss on Earth's surface, and only 1/8 of that 8000 miles up (which is the diameter of the Earth)), but still strong enough to deflect a large part of the harmful solar wind, forcing it to bend out around the Earth. Without it, solar wind would annihilate our ozone layer, expose us to the full brunt of solar radiation, and slowly strip away our atmosphere until nothing was left, a process which, on Mars, is currently in its third step.
Which leaves us with a problem. Mars has no ozone. Well, actually, that's not too big a problem; we'll be forced to live in domes anyway to trap a useful atmosphere, and the domes will need to be glass so that plants beneath them get light to grow. Fortunately, normal glass will block most UV rays on its own, and we've already invented various films and treatments (check one of them out here) that can cut out those remaining few rays and leave us safe and sunny. So, really, the ozone issue is not an issue. And, since we will be distilling our own atmosphere to fill all of these domes, an atmosphere which the sun cannot strip away, the whole solar wind stealing our air thing isn't too important either.
However, the matter of high energy cosmic rays is still a big problem. A lot of this problem will occur in space on the way to the planet, but I will deal with that in a later entry on spacecraft design. For now, I want to limit my inquiries to the colony itself. According to the Mars Radiation Environment Experiment (MARIE), radiation on the surface of Mars should be roughly equal to that on the International Space Station, at about 100-200 mSv (microSieverts) per year. To give some context, the maximum recommended lifetime dose of radiation is about 1000 mSv, which would be 10 years on Mars, not counting the radiation the first colonists would experience on the way there. Cancer risks increase by about 5.5% per Sievert, so at 1000 mSv you have a 5.5% chance, at 2000 mSv an 11% chance and so on. On Earth, we get about 0.4 mSv of cosmic radiation annually (this does not include Earth-bound radiation sources, like nuclear power plants, and bananas. Read here for more information.) So, if we want to live on Mars, chronic radiation is a problem we'll need to solve.
It gets worse. Not only is chronic radiation a possibility, but without the protection of a magnetic field, the extremely intense radiation from solar flares will hit Mars (and our poor fledgling colony) head on. Radiation during these events is sometimes over 100 times background levels. That's a ridiculous 2000 mSv per day, and sometimes these flares last a week of more! In that week, the lifetime risk of radiation induced cancer for every exposed citizen of Mars would go from 0% to 77%. A 77% chance of getting cancer. This radiation dose (.14 Gray in a week) is also high enough to cause chronic radiation syndrome, which is basically all of the nastiness that comes from working in Chernobyl on the wrong day, except drawn out over the course of a year or two. Not a pretty sight.
But who wants to move to another planet just to become a cave man? Not me. I like living on the surface, and seeing the sun once in a while. Plus, plants need light to grow, and light tends to be scarce in caves. Of course we can grow our crops underground with full spectrum light bulbs, but it costs energy, energy we could get from the sun, for free, if we could keep the radiation from killing us in our pretty little domes. How can this happen? Well, we could make our own magnetic field. Some people suggest digging into the core of Mars and blasting away with nuclear weapons trying to start a dynamo effect and make a field like Earth's, but I don't buy into the idea; feels too much like Armageddon (an excellent story, but not really related to actual science). So it seems like we should make a whole lot of small magnetic deflectors. After all, it is a very weak magnetic field that repels the solar wind on Earth, right?
Wrong. The magnetic field on Earth works because it has a lot of space to work with. An average deflection of only one degree per thousand miles will mean that everything misses the whole planet if the field takes effect 25,000 miles from the surface (because the diameter of the Earth is less than 25 degrees on a circle with radius 25000 miles, so shifting radiation by 25 degrees in any direction will make it miss Earth). At that height, Earth would have a field strength of .00098 Gauss, which is very weak, but not negligible. But, we don't have the ability to make a field that big. Magnetic fields lose power as a cube of distance, meaning that if you double distance, power drops to 1/8th.
Let's take as an example the strongest electromagnet on Earth, which is 45 Tesla, or 450,000 Gauss, about 900,000 times stronger than the Earth's magnetic field at a range of 0, with a diameter of about two meters. To put that in perspective, this magnet will literally rip a pacemaker out of your heart from ten feet away.
 |
| BOOYAH! |
A possible solution is produce a lower magnetic field, but with a much bigger radius. Suppose we built an electromagnet with a power rating of 2 Tesla, or 20000 Gauss, but a diameter of 50 miles. At 25000 miles (roughly 50*2^9), this would yield a force of .00015 Gauss, which is more than 1/6th that of Earth. So, wider magnets with smaller charges might work. If you make the magnet with superconductors, then you can run it on much less electricity, and a cooling system is a lot cheaper on a planet which is already quite cold. It would certainly cost a fortune, and take a very long time to build, probably a decade or more of concentrated effort since the crew would be so comparatively small. The thing I don't know is how much power it would take to generate a magnet like this; it could require billions of megawatts to just get the thing going. If the final power input is less than the constant several megawatts required by smaller magnets, then this sort of thing would be a worthwhile project. If the smaller magnets take less power in the long run, then they are probably the better investment, and in any case it seems likely that they will be employed as a short term solution. Whatever else is true, it looks like a good number of years on Mars before the magnetic deflector shields are fully up and running.
Tuesday, July 17, 2012
Plastics: Make it Possible!
A day or two later than I wanted this week, due to vacationing and teaching small children to write essays. But, now I am back, sun burnt, with a broken phone, and a waterlogged ear, wondering how we can make plastics on Mars.
Really, the answer is: We can't. There are no oil deposits to use in plastic creation. We can recycle plastics we bring to Mars with us, but with no major local sources, plastic making via petroleum will be prohibitively expensive. And, since we use plastics in pretty much everything, this is a pretty big deal. So, we need a functional replacement.
There are several potential replacements being developed by people who figure that Earth is going to run out of oil pretty soon, and be in a similar situation (which is true, and will make plastic alternatives, especially biodegradable ones, a pretty decent investment direction starting around 2020 or so, when rising oil prices make them the cheap alternative.) Let's look at these one at a time, and see if we can choose the best option.
One option is using mycelium. In this TED talk, Eben Bayer outlines a way to create new plastic-like materials. His company has developed a way to grow mycelium, which is basically mushroom roots, into a replacement for styrofoam, moldable into any shape, growable, and 100% compostable. It uses farm wastes like rice hulls and mulched corn husks for food, and the mycelium as a glue and polymer to provide shock or acoustical absorbency. It is fire resistant, light weight, and uses all materials with no waste, since it incorporates any un-eaten corn husks or whatnot into the structure of the end product. It makes great insulation, and they are even researching how to use this mycelium glue to replace things like particleboard and fiberboard, which are wood byproducts and thus won't be available on Mars for a long time after colonization. Really, one of the coolest companies I found, so check them out here!
It's cool, but not a complete solution. Styrofoam is only one style of polymer based material, and the process takes a bit more time and storage space than normal plastic manufacturing, since each product in a run requires a separate mold, and takes about five days to grow. That decreases turnover time, limiting capacity somewhat with regard to Earth bound use. But, on Mars, quantity won't be too important for the next hundred years or so, and mycelium has the added benefit of improving soil quality, meaning that littering with this stuff would actually help the colony out, rather than polluting. A further advantage is the fact that since this process involves growing fungus to fit a mold, the factory equipment involved is pretty simple (mulcher, cleaner, pasteurizer, and some way to mix in the fungus), and would not take up too much space on the colony ship.
So, these shrooms should definitely make the trip, but more is needed for the more diverse, high-tensile uses of plastics. You can't use Styrofoam to replace a heart valve, or as a microwaveable dish, or as the external shell of your laptop. So we look at other alternatives. One promising alternative is starch plastics, which are biodegradable, and can be worked into a wide variety of strengths and flexibilities, allowing them to substitute for most other types of plastic easily. The main drawback here is that they usually use high soil depletion food crops, such as corn, as the source of the starch. This is a double whammy on the new colony, because not only will using these crops to make plastic reduce the available food supply, growing this kind of crop in the first place will deplete nutrients from soil which is already in desperate need of enriching. Corn requires constant application of fertilizer or it will deplete soil in only a few harvests, and constant fertilizer is something that should not be counted on, on Mars. Other crops with lower soil impact will be preferable for the first few years.
The last option I want to explore is algae. Several US companies are already starting to create plastics out of algae, and although some of them use petroleum based additives the technology for pure algae plastic is not at all distant. Algae is cheap and easy to grow, hydroponic, which means it doesn't deplete soil nutrients at all, and inedible, so it doesn't have a tendency to drive up food costs on Earth, or make colonists on Mars choose between getting food or the container to put it in. It can be used almost exactly like starch to make plastics, with only slightly more processing, and can create the same wide variety of products. The one problem is that in its current incarnations, algae based plastics are not biodegradable; in other words, they are just like normal plastics. If we go to Mars, it would seem intelligent to live green from the very start, and thus never need to deal with the problems we made for ourselves on Earth. Of course, biodegradable algae plastics are not out of the question, and in fact are under development currently (see here to read more).
Really, some combination of the three is likely to be the answer to the question of Mars plastics. Algae and mycelium will be needed just to fill out the biosphere, whether we make plastics out of them or not, and corn is a food crop that we should certainly bring along, even if we don't grow it for a few years while we build up soil quality (which is a whole issue in itself, to which I will probably devote an entry at some point). Mycelium manufacturing takes the least equipment, making it most economical, but the low variety of present uses is limiting, and I wouldn't really want to drink from a styrofoam cup made of fungus, even though it would probably be very safe.
Oh, yeah, and the algae factories apparently smell like a fish market. Ah well, that's the price you pay, I suppose.
Really, the answer is: We can't. There are no oil deposits to use in plastic creation. We can recycle plastics we bring to Mars with us, but with no major local sources, plastic making via petroleum will be prohibitively expensive. And, since we use plastics in pretty much everything, this is a pretty big deal. So, we need a functional replacement.
There are several potential replacements being developed by people who figure that Earth is going to run out of oil pretty soon, and be in a similar situation (which is true, and will make plastic alternatives, especially biodegradable ones, a pretty decent investment direction starting around 2020 or so, when rising oil prices make them the cheap alternative.) Let's look at these one at a time, and see if we can choose the best option.
One option is using mycelium. In this TED talk, Eben Bayer outlines a way to create new plastic-like materials. His company has developed a way to grow mycelium, which is basically mushroom roots, into a replacement for styrofoam, moldable into any shape, growable, and 100% compostable. It uses farm wastes like rice hulls and mulched corn husks for food, and the mycelium as a glue and polymer to provide shock or acoustical absorbency. It is fire resistant, light weight, and uses all materials with no waste, since it incorporates any un-eaten corn husks or whatnot into the structure of the end product. It makes great insulation, and they are even researching how to use this mycelium glue to replace things like particleboard and fiberboard, which are wood byproducts and thus won't be available on Mars for a long time after colonization. Really, one of the coolest companies I found, so check them out here!
It's cool, but not a complete solution. Styrofoam is only one style of polymer based material, and the process takes a bit more time and storage space than normal plastic manufacturing, since each product in a run requires a separate mold, and takes about five days to grow. That decreases turnover time, limiting capacity somewhat with regard to Earth bound use. But, on Mars, quantity won't be too important for the next hundred years or so, and mycelium has the added benefit of improving soil quality, meaning that littering with this stuff would actually help the colony out, rather than polluting. A further advantage is the fact that since this process involves growing fungus to fit a mold, the factory equipment involved is pretty simple (mulcher, cleaner, pasteurizer, and some way to mix in the fungus), and would not take up too much space on the colony ship.
So, these shrooms should definitely make the trip, but more is needed for the more diverse, high-tensile uses of plastics. You can't use Styrofoam to replace a heart valve, or as a microwaveable dish, or as the external shell of your laptop. So we look at other alternatives. One promising alternative is starch plastics, which are biodegradable, and can be worked into a wide variety of strengths and flexibilities, allowing them to substitute for most other types of plastic easily. The main drawback here is that they usually use high soil depletion food crops, such as corn, as the source of the starch. This is a double whammy on the new colony, because not only will using these crops to make plastic reduce the available food supply, growing this kind of crop in the first place will deplete nutrients from soil which is already in desperate need of enriching. Corn requires constant application of fertilizer or it will deplete soil in only a few harvests, and constant fertilizer is something that should not be counted on, on Mars. Other crops with lower soil impact will be preferable for the first few years.
The last option I want to explore is algae. Several US companies are already starting to create plastics out of algae, and although some of them use petroleum based additives the technology for pure algae plastic is not at all distant. Algae is cheap and easy to grow, hydroponic, which means it doesn't deplete soil nutrients at all, and inedible, so it doesn't have a tendency to drive up food costs on Earth, or make colonists on Mars choose between getting food or the container to put it in. It can be used almost exactly like starch to make plastics, with only slightly more processing, and can create the same wide variety of products. The one problem is that in its current incarnations, algae based plastics are not biodegradable; in other words, they are just like normal plastics. If we go to Mars, it would seem intelligent to live green from the very start, and thus never need to deal with the problems we made for ourselves on Earth. Of course, biodegradable algae plastics are not out of the question, and in fact are under development currently (see here to read more).
 |
| This is algae! It's your friend! |
Really, some combination of the three is likely to be the answer to the question of Mars plastics. Algae and mycelium will be needed just to fill out the biosphere, whether we make plastics out of them or not, and corn is a food crop that we should certainly bring along, even if we don't grow it for a few years while we build up soil quality (which is a whole issue in itself, to which I will probably devote an entry at some point). Mycelium manufacturing takes the least equipment, making it most economical, but the low variety of present uses is limiting, and I wouldn't really want to drink from a styrofoam cup made of fungus, even though it would probably be very safe.
Oh, yeah, and the algae factories apparently smell like a fish market. Ah well, that's the price you pay, I suppose.
Sunday, July 8, 2012
Regarding Germs
There is an amazing opportunity waiting for us on Mars: The chance to escape, once and for all, from disease. However, is it really an opportunity? Or is it a temptation best avoided?
At first glance, Mars with it's completely sterile environment, devoid of all life, and therefore all germs, viruses, and the like, seems like a boon to humanity. We can go live there, and as long as the colonists are detoxed before flight, they will never again catch a cold, a flu, or indeed any other dangerous germ borne illness. When we move to Mars, we can simply leave germs behind, for the most part. Of course, no antibacterial soap is perfect, and no matter what, humans and their livestock will carry some pathogens into space, however, a short term quarantine before flight should allow the astronauts immune systems to finish off anything that they were carrying, and avoid picking up anything new.
When they get on board ship, their bodies will already be accustomed to defeating all the diseases they carry with them. By the end of their journey to Mars, some of those strains may have died out completely in the absence of new, defenseless hosts. Any strains that do remain are benign, and have lost the ability to hurt us without mutation.
Mutation is possible, but is a matter of odds. On Earth, bacteria populations are estimated to be 5*10^30, or 5,000,000,000,000,000,000,000,000,000,000,000. That's a lot. A whole, whole, lot. Of course this is an estimate (found here: http://www.sdearthtimes.com/et0998/et0998s8.html ), but the obvious thing is that with so many bacteria the odds of a mutation are very, very high, probably happening every second or so. Some of those mutations make deadly diseases, others might create new, useful medicinal treatments. But, now consider Mars. Presumed bacteria population: 0. How much will we bring with us?
An average human has roughly 10^14 bacteria living in and on their body (so says wikipedia here: http://en.wikipedia.org/wiki/Human_microbiome ), about 1000 species. We need these bacteria to live, so getting rid of them completely is out of the question. If we assume at least 100 people are going to Mars (I'd rather have a thousand, but that's rather unlikely), that means 10^16 bacteria. Let's double that number, to include livestock (rabbits, perhaps, and goats, maybe a few cattle), and then double it again to account for topsoil traveling with the plants on board ship (roughly a trillion bacteria per kg of soil, and I expect they will need to carry at least 20 tonnes of topsoil to create a ground layer that can grow crops for 100 people), and we can estimate 4x10^16 bacteria on board our colony ship. That means that a mutation with good odds of happening once every second on Earth will probably only happen once every five million years in our Mars colony.
That's a very big deal, because it means that Mars will probably have roughly the same strains of bacteria for the first few thousand years after colonization, since population growth after landing will be limited to the size of human settlements, and even at a very high rate of settlement, it is not likely that we will ever reach Earth-like microorganism populations. Humans will almost certainly adapt to beat all of them, and then will almost certainly not need to adapt any more, which is a problem. See, if we don't adapt, it is like our immune systems using outdated software. Imagine if you didn't update any of your computer's software for five thousand years, and then plugged into the internet. Your computer would explode. That's what it would be like for humans who live on Mars their whole lives, always exposed to the same bacteria and viruses, and then come back to Earth. They will suffer extreme immune deficiencies, which could make any Earth tourism very dangerous.
This is why I said that the lure of a disease-free Mars is a temptation. While it is true that we could solve a lot problems for individuals by eliminating disease on Mars, we would lose the ability to return safely to Earth in two generations or so. Longevity and health on Mars would come at the cost of isolation. Soon, even trading with Earth would become risky, because there is no knowing when some chance germ will ride along against which the Martian humans have no immunity. An epidemic could easily cripple the young colonies, where every person will be necessary, and one death might mean that suddenly nobody on the planet knows how to fix the air purifiers.
To some extent, this separation is unavoidable, and will almost certainly occur. There is simply no way that the Mars biosphere can keep up with the robustness of the Earth biosphere. And for some diseases, there is absolutely no reason to let them travel to Mars. For example, simple screening can completely eliminate all sexually transmitted diseases from the Martian population. AIDS will be a non-issue on Mars. Depending on how many people are willing to go, it may even be possible to be selective and create a population devoid of most genetic risk factors. Similarly, parasites and certain diseases can be done away with. For example, there is no reason to bring malaria to Mars, or any disease for which a vaccine is available, since Earth can simply send the vaccine instead and immunity can be achieved without an outbreak taking place.
But, if Mars and Earth mean to be in contact with each other, it will be necessary to intentionally expose Mars to at least the more mild Earth germs. Martian children will still need to be immunized against Earth illnesses, like tuberculosis and tetanus, and for these diseases a simple vaccine should solve the problem. The really unfortunate part is that Martian humans will also need to be exposed to incurable but common diseases as well, so that if they ever return to the home world they aren't at a physical disadvantage. The flu, the cold, and perhaps the occasional stomach bug will all be necessary ailments to make sure that Martian immune systems stay up to date. In essence, there will need to be annual germ deliveries from Earth to make sure that Mars gets sick.
And now, I am certain that my name will be cursed forever on Mars, as the one who suggested an annual "Disease Day." It's sort of a holiday. Like Christmas, except that instead of presents, you get the flu.
At first glance, Mars with it's completely sterile environment, devoid of all life, and therefore all germs, viruses, and the like, seems like a boon to humanity. We can go live there, and as long as the colonists are detoxed before flight, they will never again catch a cold, a flu, or indeed any other dangerous germ borne illness. When we move to Mars, we can simply leave germs behind, for the most part. Of course, no antibacterial soap is perfect, and no matter what, humans and their livestock will carry some pathogens into space, however, a short term quarantine before flight should allow the astronauts immune systems to finish off anything that they were carrying, and avoid picking up anything new.
When they get on board ship, their bodies will already be accustomed to defeating all the diseases they carry with them. By the end of their journey to Mars, some of those strains may have died out completely in the absence of new, defenseless hosts. Any strains that do remain are benign, and have lost the ability to hurt us without mutation.
Mutation is possible, but is a matter of odds. On Earth, bacteria populations are estimated to be 5*10^30, or 5,000,000,000,000,000,000,000,000,000,000,000. That's a lot. A whole, whole, lot. Of course this is an estimate (found here: http://www.sdearthtimes.com/et0998/et0998s8.html ), but the obvious thing is that with so many bacteria the odds of a mutation are very, very high, probably happening every second or so. Some of those mutations make deadly diseases, others might create new, useful medicinal treatments. But, now consider Mars. Presumed bacteria population: 0. How much will we bring with us?
An average human has roughly 10^14 bacteria living in and on their body (so says wikipedia here: http://en.wikipedia.org/wiki/Human_microbiome ), about 1000 species. We need these bacteria to live, so getting rid of them completely is out of the question. If we assume at least 100 people are going to Mars (I'd rather have a thousand, but that's rather unlikely), that means 10^16 bacteria. Let's double that number, to include livestock (rabbits, perhaps, and goats, maybe a few cattle), and then double it again to account for topsoil traveling with the plants on board ship (roughly a trillion bacteria per kg of soil, and I expect they will need to carry at least 20 tonnes of topsoil to create a ground layer that can grow crops for 100 people), and we can estimate 4x10^16 bacteria on board our colony ship. That means that a mutation with good odds of happening once every second on Earth will probably only happen once every five million years in our Mars colony.
That's a very big deal, because it means that Mars will probably have roughly the same strains of bacteria for the first few thousand years after colonization, since population growth after landing will be limited to the size of human settlements, and even at a very high rate of settlement, it is not likely that we will ever reach Earth-like microorganism populations. Humans will almost certainly adapt to beat all of them, and then will almost certainly not need to adapt any more, which is a problem. See, if we don't adapt, it is like our immune systems using outdated software. Imagine if you didn't update any of your computer's software for five thousand years, and then plugged into the internet. Your computer would explode. That's what it would be like for humans who live on Mars their whole lives, always exposed to the same bacteria and viruses, and then come back to Earth. They will suffer extreme immune deficiencies, which could make any Earth tourism very dangerous.
This is why I said that the lure of a disease-free Mars is a temptation. While it is true that we could solve a lot problems for individuals by eliminating disease on Mars, we would lose the ability to return safely to Earth in two generations or so. Longevity and health on Mars would come at the cost of isolation. Soon, even trading with Earth would become risky, because there is no knowing when some chance germ will ride along against which the Martian humans have no immunity. An epidemic could easily cripple the young colonies, where every person will be necessary, and one death might mean that suddenly nobody on the planet knows how to fix the air purifiers.
To some extent, this separation is unavoidable, and will almost certainly occur. There is simply no way that the Mars biosphere can keep up with the robustness of the Earth biosphere. And for some diseases, there is absolutely no reason to let them travel to Mars. For example, simple screening can completely eliminate all sexually transmitted diseases from the Martian population. AIDS will be a non-issue on Mars. Depending on how many people are willing to go, it may even be possible to be selective and create a population devoid of most genetic risk factors. Similarly, parasites and certain diseases can be done away with. For example, there is no reason to bring malaria to Mars, or any disease for which a vaccine is available, since Earth can simply send the vaccine instead and immunity can be achieved without an outbreak taking place.
But, if Mars and Earth mean to be in contact with each other, it will be necessary to intentionally expose Mars to at least the more mild Earth germs. Martian children will still need to be immunized against Earth illnesses, like tuberculosis and tetanus, and for these diseases a simple vaccine should solve the problem. The really unfortunate part is that Martian humans will also need to be exposed to incurable but common diseases as well, so that if they ever return to the home world they aren't at a physical disadvantage. The flu, the cold, and perhaps the occasional stomach bug will all be necessary ailments to make sure that Martian immune systems stay up to date. In essence, there will need to be annual germ deliveries from Earth to make sure that Mars gets sick.
And now, I am certain that my name will be cursed forever on Mars, as the one who suggested an annual "Disease Day." It's sort of a holiday. Like Christmas, except that instead of presents, you get the flu.
Sunday, July 1, 2012
I Think I'll Try Defying Gravity
This post will be weird. I talk about childbirth. Also, my idea is weird. But enough said. Let's begin.
One major problem on Mars (or, anywhere else, for that matter) is that the gravity will be different. As in, you will weigh just over one third of your Earth weight on Mars. This....could create some problems.
The largest problem, at first glance, is the same problem experienced by astronauts in the microgravity of space: loss of muscle and bone mass. A person who lives on Mars for too long, and anyone born on Mars, will probably not be able to return to Earth gravity without extreme discomfort and danger, because our bodies only grow strong enough for our environments. If my muscles think I weigh 52 lbs. and suddenly I go back to earth and weigh 140, my muscles won't be able to cope.
A related problem is bone growth. I might be born on Mars, but my genes are still designed for Earth gravity. Most of you will know that bones grow faster at night, because they are not being pressed by gravity and activity as much. As a result, the lower pressure from Mars gravity poses a major problem. Our bodies, normally programmed to grow only when we rest, may be convinced that we are always resting, and therefore that we should always be growing. Giantism could thus become epidemic, along with all of its related health problems. The effects of low or micro gravity on children have not been studied thoroughly, since all the people who have spent substantial time in space were fully grown adults. So, really, we don't know how bad this might get. It could be that just standing upright is enough to convince your bones not to go into growth mode, and if so, this is a non-issue.
Another potential problem is childbirth. Not being female, I'm not an expert, but I do know that kids skulls are subjected to some very intense pushing and smooshing on the way out, and that their skulls are soft enough on Earth that forceps delivery can sometimes cause skull fractures. If, as I suspect, low gravity means more fragile bones for the fetus, then mothers giving birth could potentially crush the skulls of their babies with the force of the muscles required to push them out. Lower gravity could also lead to an increase in breech births. The exact causes of breech births are unknown (We don't even know why most babies come out head first: I read everything from "the baby gets top-heavy" to "it's instinct" to "the mother just needed to role on the floor"), but it seems likely that there is a gravitational component involved in aiding babies when they determine which way is down. If that is the case (and I should stress again, I don't really know for sure), then lower gravity would make it harder, increasing complications.
All other complications aside, the real issue is bone and muscle mass and density. This is the problem we KNOW is real, and it would mean that Mars-born humans would have a lot of trouble making trips to Earth, which we know that someday they will probably want to do. Ergo, we must try defying gravity (teehee).
To get ideas for this, I looked into possible spacecraft designs. One major school of thought regarding interplanetary and interstellar spacecraft is to build torus shapes as habitations, and spin them to simulate gravity via centrifugal force. Build a big ring, spin it at the right speed, and stand people inside it, and they are pulled outward by exactly the same level of force that pulls us downward on Earth. The bigger the circle, the fewer the rpms need to be. Voila, microgravity problem solved. People can now stay in space as long as they want without getting all weak and breakable.
On a planet this becomes more difficult, because the planet is pulling down at the same time that the torus is pulling outward. You might have experienced a carnival ride where you stand in a padded, circular room, the room spins, and then the floor falls away. You don't fall out because you are pinned to the wall by centrifugal forces, but you can't move either, because the force needed to pin you to a wall safely is perhaps 2 Gs, and pulls you heavily into that padded wall. Less force, and you might fall out of the ride, because Earth's gravity is still present. We can only use centrifugal force to ADD gravity, we can't get rid of the existing gravity.
Mars gravity, however, is less. So we can reach Earth gravity if we can add the right amount. What we need to do is build a spinning house. Specifically, a spinning house with a curved floor. You see, the addition of two forces in different directions (in this case, one outward force, and one downward) can be seen as a single force that is their sum, a new vector, in a new direction that averages the old ones. So, if I spin a torus to add .62 g of force at a certain radius, while Mars pulls downward with .38 g, there will be a certain, perfect angle at which I can tilt the floor, where gravity will pull exactly 1 g perpendicularly.
The problem with this is that at all other radii, the force from the rotation will be different, and the angle will change. To account for this, the floor will need to be curved such that "down" is always perpendicular to the floor. If you make the radius big enough, and the rotation slow enough, the difference in angle becomes gradual, leading to a gentle upward slope away from the entrance to the building in the center. As you walk outward and up the slope, you will get heavier and heavier, but down is always directly beneath your feet. You can walk perpendicular to the slope of a hill, and a ball on the floor won't roll back down.
In fact, if the designers built the slope right, the ball would roll upward. You see, a human being sticks up off the floor, and a human's center of gravity is not at floor level. To optimize balance, it would be best to build the curve so that it fits a radius just under 1 meter less than the actual radius, so that our feet, below 1 m, are slightly heavy, and our heads, above 1 m, are slightly light, and on the whole, an average height person comes out to be Earth weight. This means objects at floor level will have more outward pull than the floor angle compensates, and will roll upward. Unfortunately, this also means that rolling office chairs will be a bad idea.
(WARNING: This paragraph may contain math type stuff.) The building itself will need to be HUGE, and the bigger it is, the better, because the bigger it is, the slower it can spin, and the less difference in weight and angle from one point on the radius to the next. At a radius of 50 m, .62 g is a rotation of 17.439m/s, a little less than 3 rpm, which, at a radius of 51 m will cause a velocity of 17.787m/s, for .632 g, increasing or decreasing by roughly 2% (.0124 g) per radial meter. So, a person 2 meters tall would have feet that were 4% heavier than his head, which might be dizzying, but would be tolerable.
This will be quite a construction project. Basically, it means building a spinning football stadium on Mars. And it can never stop, either. If the spin stops, all the furniture goes sliding down the slope. A difficult feat for engineers. This will have to be built with on-site martian materials, as shipping costs would render it completely impractical to build on Earth. Only the outer edges will really be good for human habitation. The center would make a very nice little park or low gravity playground or gymnasium. It will need a VERY reliable and substantial power supply, probably fusion, although current fission reactors would work, and I would want a triple fail-safe on the machinery, and would probably still bolt my furniture to the floor. It probably won't exist for a couple years after original Mars landing, due to all of these concerns.
However, aside from fusion power (which we could skip, but I don't want too), all of the technology is already achievable, it just needs a bit of scaling up in terms of size. Once that is done, gravity problems go away, and this can be the first apartment building on the red planet.
One major problem on Mars (or, anywhere else, for that matter) is that the gravity will be different. As in, you will weigh just over one third of your Earth weight on Mars. This....could create some problems.
The largest problem, at first glance, is the same problem experienced by astronauts in the microgravity of space: loss of muscle and bone mass. A person who lives on Mars for too long, and anyone born on Mars, will probably not be able to return to Earth gravity without extreme discomfort and danger, because our bodies only grow strong enough for our environments. If my muscles think I weigh 52 lbs. and suddenly I go back to earth and weigh 140, my muscles won't be able to cope.
A related problem is bone growth. I might be born on Mars, but my genes are still designed for Earth gravity. Most of you will know that bones grow faster at night, because they are not being pressed by gravity and activity as much. As a result, the lower pressure from Mars gravity poses a major problem. Our bodies, normally programmed to grow only when we rest, may be convinced that we are always resting, and therefore that we should always be growing. Giantism could thus become epidemic, along with all of its related health problems. The effects of low or micro gravity on children have not been studied thoroughly, since all the people who have spent substantial time in space were fully grown adults. So, really, we don't know how bad this might get. It could be that just standing upright is enough to convince your bones not to go into growth mode, and if so, this is a non-issue.
Another potential problem is childbirth. Not being female, I'm not an expert, but I do know that kids skulls are subjected to some very intense pushing and smooshing on the way out, and that their skulls are soft enough on Earth that forceps delivery can sometimes cause skull fractures. If, as I suspect, low gravity means more fragile bones for the fetus, then mothers giving birth could potentially crush the skulls of their babies with the force of the muscles required to push them out. Lower gravity could also lead to an increase in breech births. The exact causes of breech births are unknown (We don't even know why most babies come out head first: I read everything from "the baby gets top-heavy" to "it's instinct" to "the mother just needed to role on the floor"), but it seems likely that there is a gravitational component involved in aiding babies when they determine which way is down. If that is the case (and I should stress again, I don't really know for sure), then lower gravity would make it harder, increasing complications.
All other complications aside, the real issue is bone and muscle mass and density. This is the problem we KNOW is real, and it would mean that Mars-born humans would have a lot of trouble making trips to Earth, which we know that someday they will probably want to do. Ergo, we must try defying gravity (teehee).
To get ideas for this, I looked into possible spacecraft designs. One major school of thought regarding interplanetary and interstellar spacecraft is to build torus shapes as habitations, and spin them to simulate gravity via centrifugal force. Build a big ring, spin it at the right speed, and stand people inside it, and they are pulled outward by exactly the same level of force that pulls us downward on Earth. The bigger the circle, the fewer the rpms need to be. Voila, microgravity problem solved. People can now stay in space as long as they want without getting all weak and breakable.
On a planet this becomes more difficult, because the planet is pulling down at the same time that the torus is pulling outward. You might have experienced a carnival ride where you stand in a padded, circular room, the room spins, and then the floor falls away. You don't fall out because you are pinned to the wall by centrifugal forces, but you can't move either, because the force needed to pin you to a wall safely is perhaps 2 Gs, and pulls you heavily into that padded wall. Less force, and you might fall out of the ride, because Earth's gravity is still present. We can only use centrifugal force to ADD gravity, we can't get rid of the existing gravity.
Mars gravity, however, is less. So we can reach Earth gravity if we can add the right amount. What we need to do is build a spinning house. Specifically, a spinning house with a curved floor. You see, the addition of two forces in different directions (in this case, one outward force, and one downward) can be seen as a single force that is their sum, a new vector, in a new direction that averages the old ones. So, if I spin a torus to add .62 g of force at a certain radius, while Mars pulls downward with .38 g, there will be a certain, perfect angle at which I can tilt the floor, where gravity will pull exactly 1 g perpendicularly.
The problem with this is that at all other radii, the force from the rotation will be different, and the angle will change. To account for this, the floor will need to be curved such that "down" is always perpendicular to the floor. If you make the radius big enough, and the rotation slow enough, the difference in angle becomes gradual, leading to a gentle upward slope away from the entrance to the building in the center. As you walk outward and up the slope, you will get heavier and heavier, but down is always directly beneath your feet. You can walk perpendicular to the slope of a hill, and a ball on the floor won't roll back down.
In fact, if the designers built the slope right, the ball would roll upward. You see, a human being sticks up off the floor, and a human's center of gravity is not at floor level. To optimize balance, it would be best to build the curve so that it fits a radius just under 1 meter less than the actual radius, so that our feet, below 1 m, are slightly heavy, and our heads, above 1 m, are slightly light, and on the whole, an average height person comes out to be Earth weight. This means objects at floor level will have more outward pull than the floor angle compensates, and will roll upward. Unfortunately, this also means that rolling office chairs will be a bad idea.
(WARNING: This paragraph may contain math type stuff.) The building itself will need to be HUGE, and the bigger it is, the better, because the bigger it is, the slower it can spin, and the less difference in weight and angle from one point on the radius to the next. At a radius of 50 m, .62 g is a rotation of 17.439m/s, a little less than 3 rpm, which, at a radius of 51 m will cause a velocity of 17.787m/s, for .632 g, increasing or decreasing by roughly 2% (.0124 g) per radial meter. So, a person 2 meters tall would have feet that were 4% heavier than his head, which might be dizzying, but would be tolerable.
This will be quite a construction project. Basically, it means building a spinning football stadium on Mars. And it can never stop, either. If the spin stops, all the furniture goes sliding down the slope. A difficult feat for engineers. This will have to be built with on-site martian materials, as shipping costs would render it completely impractical to build on Earth. Only the outer edges will really be good for human habitation. The center would make a very nice little park or low gravity playground or gymnasium. It will need a VERY reliable and substantial power supply, probably fusion, although current fission reactors would work, and I would want a triple fail-safe on the machinery, and would probably still bolt my furniture to the floor. It probably won't exist for a couple years after original Mars landing, due to all of these concerns.
However, aside from fusion power (which we could skip, but I don't want too), all of the technology is already achievable, it just needs a bit of scaling up in terms of size. Once that is done, gravity problems go away, and this can be the first apartment building on the red planet.
Friday, June 22, 2012
Mars > Moon
I was going to wait until next week to write this one, but I got too excited. So, here is post number two, a full four days early.
Some people will almost certainly wonder: Why go to Mars? If the main purpose is to get leibensraum, then the Moon offers a lot of good space to live, and is much cheaper and closer to home. People on the moon might even be able to go vacationing on Earth! Surely the moon is the logical first step.
Well, there are arguments either way, I suppose, and I fully approve of building moon cities as well as Mars cities, but I do think that Mars cities will be easier to build, easier to live in, and above all else, easier to sustain. There is one very big reason for this: Air.
The moon has no atmosphere of any kind. It is empty space straight down to the rock. This presents a few unique challenges for colonists. First, as a colony ship was descending to the surface, it would need to use thrusters (and therefore fuel) to control its descent. There can be no airbraking, since there is no atmosphere. That means that the landing craft will have to be designed far differently than our current aircraft, and have an increased fuel capacity, which will make them heavier, and thus more expensive, offsetting some of the cost difference between Mars and the moon.
Once landed, with no air on the moon, a colony will need to import its own atmosphere. This is possible, of course, but difficult, and, as before, expensive, further offsetting the cost differences between Mars and the moon, but this will really cause problems when it comes to colony expansion. Every time a settlement on the moon gets overpopulated, the people will need to get an air delivery from Earth before they can build a new settlement. This means colonial development will be tied intrinsically to Earth, and population expansion thus strictly limited. If the lunar colonies wanted to produce air of their own, they would have to mine it, and then chemically separate the various components from the rocks they dug up, a time consuming, and expensive process, and less effective than it would be even on Earth, since lunar soil is less oxidized, and has no organic nitrate contributions. In short, just getting air to breathe would be a problem for generations.
Another issue is that on the moon, there could never be an aerodynamically based travel system. No air, no airlines. If ever the Moon reached a stage of development where there were multiple cities, all transit between them would have to be by train, or lunar buggy, because airplanes and helicopters simply wouldn't work, and travel by rocket is likely to be prohibitively expensive on a world where oil and accessible chemical fuels don't exist. Hydrogen fuel would be possible, but creating it would have to be done at the expense of destroying the already relatively small lunar water supply (more on that later). Not that trains are bad; they might, in fact, be better for the colony. But the point is that flight on the moon would be limited only to rockets leaving, and landers coming in.
Mars, on the other hand, has an atmosphere. This means that landing spacecraft can use drag chutes, airbrakes, and aerodynamically controlled flight to get where they want to go without needing extra fuel. It means that Mars Airlines is someday going to be a possibility, and flying in to remote areas for exploration or rescue will be something that can be done quite cheaply. The Martian atmosphere will need refining, but all the gases needed for Earth atmosphere are present, so making ourselves some breathable air will mostly involve mixing, not mining. The atmosphere does lack oxygen, but it has abundant CO2 for plants, which can then synthesize the oxygen we need. Turning rocks into air won't be very necessary. As a result, a Mars colony could grow much more easily.
The issue of water will also come into play eventually. Mars has substantial water reserves in the form of polar ice caps and there is also evidence of water permafrost, and even geological evidence of flowing water at some time in the past. We can access water there by simply digging up and thawing the soil, and if we melted the ice cap we could cover the whole surface of Mars 5 meters deep (only the area, mind you; elevation was not included in this calculation). The moon, by comparison, is extremely dry. There is some water present, recently discovered in the deep shadows of polar craters, but the total estimates are only 500-700 million tonnes (I will assume that these are metric tonnes, though the article I was reading didn't specify), which is 500-700 billion liters. For comparison, Earth currently uses about 6 trillion liters of water per day just to support humans (not including the water used by animals and non-crop plants), which means we would go through the entire water supply of the moon ten times daily.
Water can be recycled, but not quickly; much is trapped in the living organisms necessary to maintain a viable biosphere. In short, we could expect, by harvesting all the easily available water on the moon, to supply drinking and irrigation water for a good sized city, perhaps even a few million people, with stringent water conservation laws. The most water rich areas of the moon, even with the recent discoveries, are roughly as wet as the Gobi, a little wetter than the Sahara or Atacama deserts. Whereas, on Mars, we could have swimming pools, showers, and hot tubs, and probably support a billion people comfortably with sustainable conservation measures.
On Mars, two of the biggest problems are expected to be the lack of a magnetic shield from solar radiation, and possibly dust storms. As for the first, the moon has the same problem; either place, we will have to create a magnetic field of our own, or else develop some other sort of radiation shielding. As for the dust, on that point the moon is a clear winner. Mars sometimes has planet wide dust storms, which would frankly be terrifying. However, the lunar victory on this point is not unqualified; solar wind does blast some dust up off the surface to play havoc with instruments and filters. And, worse than that, lunar dust is electrically charged due to constant exposure to solar radiation, and will statically cling to any uncharged thing it touches, a habit which could cause problems. So, while the moon won't have dust storms like Mars, a lunar colony will still have dust to deal with.
Lastly, the temperature. On Mars, average temperatures range from -87 C (spit is ice) to 0 C (still cold, but bearable with a good stout coat). You wouldn't want to go out and play, since you can't breath the atmosphere, but the variation is tolerable for most machines without too much redesign. We've even measured -89 C on Earth, so life on Mars would roughly equate to life in Antarctica. On the moon there is no air, so of course there is no air temperature. But the surface temperature of the moon varies hugely, over 250 C, from above boiling on the light side to dry ice on the cold side. Any equipment would have to withstand huge and rapid temperature fluctuations.
Now don't get me wrong, I think that colonizing the moon is a great idea. In general, I am enthusiastic about colonizing pretty much any rock we can fly to, since the more places we go, the more we discover, and the more humanity can grow and learn. Even today, I spent a good couple hours trying to figure out if kite colonies on Saturn, Neptune, and Uranus are feasible (All three planets have atmospheric regions where the temperature and gravity are roughly Earthlike, and the pressure is high (10-50 bar), but survivable with modern technology. Neptune seemed especially promising, with a potential water belt right in the temperature zone I wanted. However, the winds (1200 mph in some cases) made me conclude that though a giant kite or plane could fly there permanently, the turbulence would make the life of colonists very uncomfortable.). But, whenever I think about where to go first, I think that Mars will be the easiest colony to land, the easiest to make permanent, and the easiest to expand using only local resources.
In short: Mars wins.
Some people will almost certainly wonder: Why go to Mars? If the main purpose is to get leibensraum, then the Moon offers a lot of good space to live, and is much cheaper and closer to home. People on the moon might even be able to go vacationing on Earth! Surely the moon is the logical first step.
Well, there are arguments either way, I suppose, and I fully approve of building moon cities as well as Mars cities, but I do think that Mars cities will be easier to build, easier to live in, and above all else, easier to sustain. There is one very big reason for this: Air.
The moon has no atmosphere of any kind. It is empty space straight down to the rock. This presents a few unique challenges for colonists. First, as a colony ship was descending to the surface, it would need to use thrusters (and therefore fuel) to control its descent. There can be no airbraking, since there is no atmosphere. That means that the landing craft will have to be designed far differently than our current aircraft, and have an increased fuel capacity, which will make them heavier, and thus more expensive, offsetting some of the cost difference between Mars and the moon.
Once landed, with no air on the moon, a colony will need to import its own atmosphere. This is possible, of course, but difficult, and, as before, expensive, further offsetting the cost differences between Mars and the moon, but this will really cause problems when it comes to colony expansion. Every time a settlement on the moon gets overpopulated, the people will need to get an air delivery from Earth before they can build a new settlement. This means colonial development will be tied intrinsically to Earth, and population expansion thus strictly limited. If the lunar colonies wanted to produce air of their own, they would have to mine it, and then chemically separate the various components from the rocks they dug up, a time consuming, and expensive process, and less effective than it would be even on Earth, since lunar soil is less oxidized, and has no organic nitrate contributions. In short, just getting air to breathe would be a problem for generations.
Another issue is that on the moon, there could never be an aerodynamically based travel system. No air, no airlines. If ever the Moon reached a stage of development where there were multiple cities, all transit between them would have to be by train, or lunar buggy, because airplanes and helicopters simply wouldn't work, and travel by rocket is likely to be prohibitively expensive on a world where oil and accessible chemical fuels don't exist. Hydrogen fuel would be possible, but creating it would have to be done at the expense of destroying the already relatively small lunar water supply (more on that later). Not that trains are bad; they might, in fact, be better for the colony. But the point is that flight on the moon would be limited only to rockets leaving, and landers coming in.
Mars, on the other hand, has an atmosphere. This means that landing spacecraft can use drag chutes, airbrakes, and aerodynamically controlled flight to get where they want to go without needing extra fuel. It means that Mars Airlines is someday going to be a possibility, and flying in to remote areas for exploration or rescue will be something that can be done quite cheaply. The Martian atmosphere will need refining, but all the gases needed for Earth atmosphere are present, so making ourselves some breathable air will mostly involve mixing, not mining. The atmosphere does lack oxygen, but it has abundant CO2 for plants, which can then synthesize the oxygen we need. Turning rocks into air won't be very necessary. As a result, a Mars colony could grow much more easily.
The issue of water will also come into play eventually. Mars has substantial water reserves in the form of polar ice caps and there is also evidence of water permafrost, and even geological evidence of flowing water at some time in the past. We can access water there by simply digging up and thawing the soil, and if we melted the ice cap we could cover the whole surface of Mars 5 meters deep (only the area, mind you; elevation was not included in this calculation). The moon, by comparison, is extremely dry. There is some water present, recently discovered in the deep shadows of polar craters, but the total estimates are only 500-700 million tonnes (I will assume that these are metric tonnes, though the article I was reading didn't specify), which is 500-700 billion liters. For comparison, Earth currently uses about 6 trillion liters of water per day just to support humans (not including the water used by animals and non-crop plants), which means we would go through the entire water supply of the moon ten times daily.
Water can be recycled, but not quickly; much is trapped in the living organisms necessary to maintain a viable biosphere. In short, we could expect, by harvesting all the easily available water on the moon, to supply drinking and irrigation water for a good sized city, perhaps even a few million people, with stringent water conservation laws. The most water rich areas of the moon, even with the recent discoveries, are roughly as wet as the Gobi, a little wetter than the Sahara or Atacama deserts. Whereas, on Mars, we could have swimming pools, showers, and hot tubs, and probably support a billion people comfortably with sustainable conservation measures.
On Mars, two of the biggest problems are expected to be the lack of a magnetic shield from solar radiation, and possibly dust storms. As for the first, the moon has the same problem; either place, we will have to create a magnetic field of our own, or else develop some other sort of radiation shielding. As for the dust, on that point the moon is a clear winner. Mars sometimes has planet wide dust storms, which would frankly be terrifying. However, the lunar victory on this point is not unqualified; solar wind does blast some dust up off the surface to play havoc with instruments and filters. And, worse than that, lunar dust is electrically charged due to constant exposure to solar radiation, and will statically cling to any uncharged thing it touches, a habit which could cause problems. So, while the moon won't have dust storms like Mars, a lunar colony will still have dust to deal with.
Lastly, the temperature. On Mars, average temperatures range from -87 C (spit is ice) to 0 C (still cold, but bearable with a good stout coat). You wouldn't want to go out and play, since you can't breath the atmosphere, but the variation is tolerable for most machines without too much redesign. We've even measured -89 C on Earth, so life on Mars would roughly equate to life in Antarctica. On the moon there is no air, so of course there is no air temperature. But the surface temperature of the moon varies hugely, over 250 C, from above boiling on the light side to dry ice on the cold side. Any equipment would have to withstand huge and rapid temperature fluctuations.
Now don't get me wrong, I think that colonizing the moon is a great idea. In general, I am enthusiastic about colonizing pretty much any rock we can fly to, since the more places we go, the more we discover, and the more humanity can grow and learn. Even today, I spent a good couple hours trying to figure out if kite colonies on Saturn, Neptune, and Uranus are feasible (All three planets have atmospheric regions where the temperature and gravity are roughly Earthlike, and the pressure is high (10-50 bar), but survivable with modern technology. Neptune seemed especially promising, with a potential water belt right in the temperature zone I wanted. However, the winds (1200 mph in some cases) made me conclude that though a giant kite or plane could fly there permanently, the turbulence would make the life of colonists very uncomfortable.). But, whenever I think about where to go first, I think that Mars will be the easiest colony to land, the easiest to make permanent, and the easiest to expand using only local resources.
In short: Mars wins.
Wednesday, June 20, 2012
A Whole New Red Party
I am running for President of the United States in 2040. Whatever planks I may use to compose my platform (who can say what issues will arise from the muddied abyss that is American politics?), my main goal in this is simple: I need access to a trillion dollars of US tax money. Why? Because I know the best possible use for it.
What is the best thing a person can do with a trillion dollars? Solve world hunger? Rebuild aging infrastructure and thus spur economic recovery? Bribe China not to take over the world? Better: Move to another planet. Specifically, a small, cold, reddish one.
"But, Sir!" you will undoubtedly protest, "You will only be able to take perhaps a thousand people to Mars! A trillion dollars for a thousand people? Ridiculous! There's not even anything on Mars that we want! Don't go to Mars, end world hunger instead! Mars is a waste of money!"
To you, I have a variety of responses. First, World Hunger is also on my to do list, and will cost ever so much less money to solve. Basically, it is a matter of increasing the US beef price with taxes so that demand drops, and having the government buy surplus feed grain and sell it at a loss in impoverished nations (funded by the money from the taxes on beef). We eat less meat, and are healthier, and the poor in the third world get to eat, and are healthier, and the beef manufacturers are angry, but they can suck it up. Done. Now on to real business.
Second, the idea that there's nothing we want on Mars is, if I may put it bluntly, an utterly stupid, small minded idea. Or else, perhaps entirely correct. We don't want anything ON Mars. What we want is MARS ITSELF. I'm not saying go there, mine, bring back minerals, trade, etc. I'm saying go to Mars, and live. Just live. What do we get out of that? A planet. A whole planet. Real estate. That's why we go to Mars: it is another place for us to live, and the land area is roughly equal to the combined land area of all the continents of Earth.
Thinking in terms of dollar and cents economics with regard to Mars is ridiculous. How valuable is Mars? How valuable is the Earth? Mars is about a third the size, so, given a thousand years of growth to build cities and ecosystems, we can expect Mars to be worth about a third of the price. How much to buy a third of the Earth? Much more than a trillion dollars. More, even, than a trillion dollars with a thousand years of interest on top. In short, the investment is good in its own right.
But, even without real estate, we can expect a very high return on investment when it comes to going to Mars. How do I know? Well, consider this: NASA has produced more patents than any other government office, and the proceeds from those inventions go right back into government coffers. Currently, the USA makes five times NASA's annual budget from these patents. If NASA itself actually received the proceeds of its own work, we would probably be living on Mars already. Now, I do not claim that a trillion dollar mission to Mars will produce 5 trillion dollars per anum of revenue, and I do not claim that the revenue will be recovered instantly. However, I do claim that with great problems come great inventions, and I don't think it unreasonable to expect this trip to pay for itself over the following few years, and then start generating big profits for the USA, which will translate to increased revenue for the government, which then will become either more benefits or less taxes for the American public.
So, we will make money, we will own another planet, but neither of these are the main reason to go to Mars. The main reason is that going to Mars will save mankind from cataclysm and possible extinction. Yes. Cataclysm and possible extinction. To many those sound like doom and gloom fear-mongering words, but let me explain. No, the Earth is not currently on the brink of disaster. The greatest danger at the moment to the survival of humanity itself is humanity itself, via the threat of nuclear war, which we can all agree is dwindling nicely. But I am talking about asteroids. A collision with a large asteroid could disrupt plate tectonics, unleash earthquakes and tsunamis the likes of which have never been recorded, and, most importantly, block the sun with dust. The last is most important, because a blocked sun will mean winter weather for possibly years. It will mean that plants have little or no light to grow by. It will mean crops die. It will mean that after the earthquakes, and tsunamis are over, when the remnants of humanity are pulling together to bring civilization back from the ashes, they won't succeed, because they will starve to death.
When will this happen? Well, it happens roughly every two million years in a cataclysmic way, and we are due in the next few hundred thousand. In a "human extinction" way? Perhaps once every two hundred million years. So, we probably have a while to wait. Probably. If we don't nuke ourselves to death first, which we probably won't. Probably.
I don't like probably. Not at all. Especially not when the statement is "The human race will probably be alive a thousand years from now." I would much prefer "The human race will DEFINITELY be alive a billion years from now." And that is exactly the promise that Mars holds for us. Because, while Mars too will occasionally be hit by giant asteroids that will destroy all life, those asteroids will never hit both Mars and Earth simultaneously. That means that when it happens, we can repopulate. If we can establish permanent, self sustaining settlements on Mars, the human race will live until the Sun burns out (unless we kill ourselves, and even that becomes more difficult). Instead of a few hundred thousand years, we buy ourselves a few billion.
So, yes. When I am president, I will end world hunger, operate a bipartisan cabinet, oppose high priced pharmaceuticals, broker peace in the Middle East even at the expense of Israeli power, support tax breaks for environmentally friendly citizens, create a simple and fair tax system with no loopholes for the rich and a living wage deduction for the poor, and end world hunger. But none of these are the point. These decisions will be important for a decade, maybe even a century if I am lucky. But I like to think long term. Like, where will we be in a hundred million years? And, if we don't branch off this rock, the answer to that question is simple: nowhere.
What is the best thing a person can do with a trillion dollars? Solve world hunger? Rebuild aging infrastructure and thus spur economic recovery? Bribe China not to take over the world? Better: Move to another planet. Specifically, a small, cold, reddish one.
"But, Sir!" you will undoubtedly protest, "You will only be able to take perhaps a thousand people to Mars! A trillion dollars for a thousand people? Ridiculous! There's not even anything on Mars that we want! Don't go to Mars, end world hunger instead! Mars is a waste of money!"
To you, I have a variety of responses. First, World Hunger is also on my to do list, and will cost ever so much less money to solve. Basically, it is a matter of increasing the US beef price with taxes so that demand drops, and having the government buy surplus feed grain and sell it at a loss in impoverished nations (funded by the money from the taxes on beef). We eat less meat, and are healthier, and the poor in the third world get to eat, and are healthier, and the beef manufacturers are angry, but they can suck it up. Done. Now on to real business.
Second, the idea that there's nothing we want on Mars is, if I may put it bluntly, an utterly stupid, small minded idea. Or else, perhaps entirely correct. We don't want anything ON Mars. What we want is MARS ITSELF. I'm not saying go there, mine, bring back minerals, trade, etc. I'm saying go to Mars, and live. Just live. What do we get out of that? A planet. A whole planet. Real estate. That's why we go to Mars: it is another place for us to live, and the land area is roughly equal to the combined land area of all the continents of Earth.
Thinking in terms of dollar and cents economics with regard to Mars is ridiculous. How valuable is Mars? How valuable is the Earth? Mars is about a third the size, so, given a thousand years of growth to build cities and ecosystems, we can expect Mars to be worth about a third of the price. How much to buy a third of the Earth? Much more than a trillion dollars. More, even, than a trillion dollars with a thousand years of interest on top. In short, the investment is good in its own right.
But, even without real estate, we can expect a very high return on investment when it comes to going to Mars. How do I know? Well, consider this: NASA has produced more patents than any other government office, and the proceeds from those inventions go right back into government coffers. Currently, the USA makes five times NASA's annual budget from these patents. If NASA itself actually received the proceeds of its own work, we would probably be living on Mars already. Now, I do not claim that a trillion dollar mission to Mars will produce 5 trillion dollars per anum of revenue, and I do not claim that the revenue will be recovered instantly. However, I do claim that with great problems come great inventions, and I don't think it unreasonable to expect this trip to pay for itself over the following few years, and then start generating big profits for the USA, which will translate to increased revenue for the government, which then will become either more benefits or less taxes for the American public.
So, we will make money, we will own another planet, but neither of these are the main reason to go to Mars. The main reason is that going to Mars will save mankind from cataclysm and possible extinction. Yes. Cataclysm and possible extinction. To many those sound like doom and gloom fear-mongering words, but let me explain. No, the Earth is not currently on the brink of disaster. The greatest danger at the moment to the survival of humanity itself is humanity itself, via the threat of nuclear war, which we can all agree is dwindling nicely. But I am talking about asteroids. A collision with a large asteroid could disrupt plate tectonics, unleash earthquakes and tsunamis the likes of which have never been recorded, and, most importantly, block the sun with dust. The last is most important, because a blocked sun will mean winter weather for possibly years. It will mean that plants have little or no light to grow by. It will mean crops die. It will mean that after the earthquakes, and tsunamis are over, when the remnants of humanity are pulling together to bring civilization back from the ashes, they won't succeed, because they will starve to death.
When will this happen? Well, it happens roughly every two million years in a cataclysmic way, and we are due in the next few hundred thousand. In a "human extinction" way? Perhaps once every two hundred million years. So, we probably have a while to wait. Probably. If we don't nuke ourselves to death first, which we probably won't. Probably.
I don't like probably. Not at all. Especially not when the statement is "The human race will probably be alive a thousand years from now." I would much prefer "The human race will DEFINITELY be alive a billion years from now." And that is exactly the promise that Mars holds for us. Because, while Mars too will occasionally be hit by giant asteroids that will destroy all life, those asteroids will never hit both Mars and Earth simultaneously. That means that when it happens, we can repopulate. If we can establish permanent, self sustaining settlements on Mars, the human race will live until the Sun burns out (unless we kill ourselves, and even that becomes more difficult). Instead of a few hundred thousand years, we buy ourselves a few billion.
So, yes. When I am president, I will end world hunger, operate a bipartisan cabinet, oppose high priced pharmaceuticals, broker peace in the Middle East even at the expense of Israeli power, support tax breaks for environmentally friendly citizens, create a simple and fair tax system with no loopholes for the rich and a living wage deduction for the poor, and end world hunger. But none of these are the point. These decisions will be important for a decade, maybe even a century if I am lucky. But I like to think long term. Like, where will we be in a hundred million years? And, if we don't branch off this rock, the answer to that question is simple: nowhere.
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