New Mars Forums

Hi Rex!   One or two points about the images you mention.
   It is intriguing that the red filter gives such clear dark spots while the blue filter all but eliminates them. And, given that chlorophyll absorbs red light selectively, I see where you're coming from on this!
   But what about the NASA explanation? Do we know of any kinds of "dark sand" which would give the same effect? Obviously, if there is a perfectly rational mineralogical explanation, and being obliged to employ Occam's Razor in such cases, then we must assume we're looking at dark sand!
   Another thing I noticed is that the spots all seem to be "smeared" to the lower left of their craters. (If up is north, this smearing is toward the south-south west.) In fact, the dark colouring seems to climb up the crater wall, and even extend well beyond it in one case. If, as you contend, the colouring is due to life forms dependent on transient surface water at the lowest point on the crater floor, why would such a life form grow up the dry crater wall and out onto the freezing, dry, wind-scoured plains? And why is that "growth" taking place in the same direction in the case of each crater?
   I don't want to argue against life on the surface of Mars. In fact, as I've said more than once in New Mars, I'm quite convinced that there is life on Mars' surface; perhaps all over the place! But I know what NASA is going to say here: The dark markings are just sand, and the reason for the smearing, always in the same direction, is simply because of the prevailing winds.
   And, if we can't show that it's impossible for sand to selectively reflect different wavelengths of light so effectively, then we probably have no choice but to accept their explanation; whether we like it or not.
   Come back to me, Rex, and convince me NASA is wrong. Nobody would be happier than me if you did!!

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You're absolutely right, Zak. Gravity is such a huge impediment to our access to space that even quite small reductions in its effect would save us a fortune in getting out of Earth's gravity well.
   But it seems unlikely to me, in the light of historical precedent, that a 2% reduction in gravity would be the limit of this machine's performance. If we optimistically assume that the machine actually modifies gravity, in however small a way, you can be sure that every facility on the planet will be made available to enhance its performance! When Phobos compares such a development to the advent of the liquid-fuelled rocket, he/she demonstrates a mastery of understatement unparalleled in human history! This would be THE EVENT of human existence, opening up for us a future such as is difficult to describe adequately in words.
   I, for one, am still watching the calendar and waiting for word to emerge from NASA. I suppose it's fun to anticipate, even if nothing comes of it. But what if it does .... ?!!

Never mind the technicalities! What an absolutely heart-wrenchingly beautiful picture of our next planetary home!!!
   I don't know what it is about Mars portrayed in this form, but it just gets to me in a way I find very difficult to put into words. It must be some sort of obsession because I can't fathom why everybody in the world doesn't feel the same way about it!
   Sorry to have changed the subject!               

Funny how things change, isn't it? For years nobody dared bring up the subject of nuclear powered spacecraft .... remember all the fuss over Cassini with its RTG?
   Now, after 9/11, the Bush administration and NASA are happy to announce they're pushing ahead with nuclear rockets in space and nobody even blinks! Has anyone noticed any press campaigns against it? Where are all the "greenies"?
   Not that I'm against nuclear power in space .... best place for it, probably. (If disposed of properly, the waste certainly won't be contaminating good old Mother Earth.)
   But in spite of all the good it will do the exploratory side of space utilisation, you don't have to be a genius to see why President Bush & Co. are so keen all of a sudden: Nuclear reactors in orbit around Earth can be used to power all those neat toys the military has been writing to Santa about for years! Imagine lasers and particle-beam weapons in orbit with almost unlimited power on tap from a high-output atomic reactor. They must have to place "Caution Wet Floor" signs all over the Pentagon because of the drooling! And in the aftermath of the terrorist attacks on American soil, there is little danger of any serious opposition from environmentalists or those against the proliferation of weapons in space.
   Still, if you look at China's recent pronouncements on their future in space, it looks like they're serious about establishing a permanent place for themselves among the space-faring nations. And I don't believe they're doing it for the greater good of humanity either! If there are going to be orbiting nuclear weapons of whatever type, I'd sooner they have the Stars and Stripes painted on them than the flag of either China or the Russian Federation!
   So, for whatever reason, let's go ahead and harness the enormous power of the atom to help us advance the exploration of the solar system. We can't go on relying on chemical rockets which are obviously not up to the job.
   Maybe, as a much-needed offshoot of all this, we'll end up with the means to defend ourselves against the asteroid threat; a real-life "Spaceguard" as envisaged by Sir Arthur C. Clarke (and others).
   Would this view of mine be representative of all or most of the Mars Society? Or are there members who really don't want to see nuclear power in space? If not, why not?
   Over to you!
                                                       

Well .... Ron Koczor at NASA has had a month so far to test his machine.
   No sign yet of any excited scientists on CNN announcing astounding experimental results and predicting a revolution in transportation!
   Still, Dr. Koczor did say 6 months, and we must be patient; difficult though that's going to be under the circumstances!

Congratulations bill on having the courage to launch into writing. A lot of us like to imagine we have the talent and the tenacity to try it but few of us ever do!
   My grasp of orbital mechanics is tenuous, to say the least, but I may be able offer some small assistance.
   I note you have chosen an exhaust velocity of 10,495.8 kms/sec for your ship, and then you set this as your ship's velocity. ( I'm not sure why you don't set the ship's velocity closer to twice this level, in accordance with Zubrin's figures?)  In any event, you ask how long it would take, at an acceleration of 0.4g, to reach 10,495.8 kms/sec. Using an equation I remember from highschool: s = ut + 1/2 at*2  (where s = distance, u = initial velocity, t = time, and
a = acceleration), and with a little judicious transposition of terms, and inserting your values of velocity and acceleration, I came up with a time of 8 weeks, 5 days, and some 22 hours!!
   At first I thought I must have made an error. It seemed like too long a time to accelerate to 10,495.8 kms/sec. Then I realised just how fast that speed really is: it's 3.5% the speed of light!
   I think from this you will see the problem. If you could instantaneously attain a speed of 0.035c (where c = light speed in vacuo), you might very well get from Mars to Saturn in not much more than 31 hours and 45 minutes. However, even at the very respectable acceleration of 0.4g, you have no hope of reaching that velocity in a reasonable (from your story's point of view) timeframe. In other words, its going to take a lot longer than you'd hoped.
   Even if we assume you can maintain a constant acceleration of 1g, it's still going to take you about 3.5 weeks to reach 10,495.8 kms/sec.
   Another problem may be how much reaction mass you can carry and how long you can keep on pushing it out at these high velocities. Although a fusion powered rocket is going to be far more efficient than any chemical (or fission powered) rocket, it is still a rocket. It still relies on throwing something backwards in order to go forwards! How much reaction mass does it take to keep accelerating at 0.4g for so long? How much can you reasonably expect to carry?
   I regret I don't know the answers to these questions but I hope I've at least thrown some light on the limitations of the situation. I think, bill, it's more complicated than you thought and it would be best to seek the advice of someone with some real "smarts" in this department.
   Incidentally, this whole topic gives you an appreciation of authors like Sir Arthur C. Clarke, who do all the arithmetic for their stories and make them sound so plausible by including just enough fact to hide the fiction!!
   A fascinating topic, bill. But is there anybody out there who can really "flesh out" the mathematics and set this comic book story on its rightful path to publication?
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I like the idea of nuclear rockets if they are going to produce the goods and get us to Mars in, say, 4 to 6 weeks instead of 6 to 8 months. Especially if disposal of spent nuclear fuel is going to be safe and easy.
   Has anybody heard any more about that Israeli scientist's Americium-powered nuclear rocket engine? Apparently you can sustain fission in even thin sheets of Americium, which means you just pump propellant straight between the sheets of Americium which heat it up to very high temperatures on its way to the exhaust nozzle. Very simple and efficient. And I think the one-way time to Mars was supposed to be reduced to about a month with such an engine.
   Imagine the savings in consumables alone(!), and you could possibly ignore the zero-g problems too with such brief transit times.
   I'm not sure about the relative merits of thermal nuclear versus plasma engines. Does anyone have projected figures for the journey time to Mars with the various types of motor? Because time is really what counts in the end, isn't it?

Excellent stuff CaptainRich, RobS, and Phobos .... so much food for thought!!
   Given that surface conditions on Mars are effectively a vacuum, we are going to have trouble not only with the temperature but also with pressure. So I think the tented area will become a must. However, I'm not sure of the evaporation rate of moisture at, say, 15-20 degreec C under conditions of about 320 mbars. I suspect it will result in the concrete drying out way too fast, which apparently leads to a weaker structure.
   Now we could always pump up the tent to a higher pressure; 1 bar would give us Earth conditions, which we're familiar with, and the problem would be solved.
   But from what I can make out here, we're dealing with a necessarily portable "bubble" which can be moved along as each section of the building is completed (yes?). Even assuming we can get away with 320 mbars, which I very much doubt, that means a vertical pressure on the tent of at least 3.3 tonnes for every square metre of ground surface enclosed. Allowing for a bit of "elbow room" in which to work, it seems likely that an area of about 100 sq. metres at a time will need to be tented, which gives a vertical force of at least 330 tonnes!
   It's one thing to talk about a permanent dome with massive footings to restrain it, but how are you going to hold down what is effectively a hot-air ballon with 330 tonnes of lift, using temporary anchoring devices?! And then blithely shift it along about 10 metres every few days?
   As a matter of fact, I can see that this whole thing could become a bit of a "chicken and egg" conundrum for cementing or concreting of any sort on Mars. It seems you need strong footings (presumably of concrete) in order to anchor a tent or dome, but you need a fairly well-pressurised dome before you can mix and pour the concrete!!
   I think Phobos is right when he/she suggests that a completely new system of building may have to be devised for Martian conditions.
   A thought just occurred to me: What about bricks which interlock like a 3-D jigsaw puzzle with some sort of specially formulated epoxy sealer or glue between them? That way we get away from the water-based-material problem which is what's causing most of the trouble.
   Any thoughts?
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Just after Proto-Earth was hit by that Mars-size (or bigger) object, its rotation period (day) was approximately 5 hours long. Is there any indication of its rotation period prior to the impact?
   Tidal forces and transfer of angular momentum have slowed Earth's rotation and pushed the moon further away; hence our current 24 hour day. But Mars has never had (as far as we know) a moon of sufficient mass to influence its rotation. Does this mean Mars has always had a day of 24 hours, 39 minutes, and 23 seconds?
   In addition to these questions, how about a metaphysical one! : Is it not remarkably "spooky" that our next-door planet has practically the same length of day as we do, after 4.6 billion years of totally independent and profoundly different history?!
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Alexander raises very pertinent issues about corruption in government; which, of course, is what we're all trying to minimise in any future governmental system on Mars.
   I use the word "minimise" because it is probably impossible to eliminate corruption. Too many people are too easily swayed by their own greed.
   The kind of government you mention, where the people make all the decisions directly, is probably more feasible today than ever before because of electronic communications. As has been mentioned elsewhere in this section of Forums, everybody could vote on every issue via their home computer.
   I suspect, though, that after the initial novelty wore off, a lot of people would abandon voting in favour of other pursuits. It would mostly be such boring statutory stuff that all but the most politically motivated people would just give up.
   But the Swiss system might satisfy MOST of Alexander's requirements for fair government. As I understand it, if a particular issue catches the attention of the public, they can instigate a referendum on it by gathering a certain number of signatures on a petition (100,000 from memory but I am ready to be corrected on this). This way, if something makes enough people hot under the collar, the government has to act upon it. But the average person doesn't have to get involved in the more humdrum day-to-day decision making which is best handled by politicians paid to do it. I'm sure this system is imperfect too, but it seems to offer more of a 'hands-on' opportunity to the ordinary citizen.
   What do others think about it?
   ( Incidentally and just for the record, I'm not actually advocating constitutional monarchy for Mars. I have a very open mind about it all. But I would urge caution in setting up anything too 'brand new'. History has shown that it can take a long time to eliminate all the loop-holes in a new constitution, and dictators have emerged by squeezing through those loop-holes. A tried and trusted system, however flawed, may therefore be preferable to something untried. I always think of that old adage: "The price of liberty is constant vigilance".)
                                                       

Wow!! Just imagine channeling two thirds of US$370 billion into research and space exploration! That is one utopian thought, Phobos!
   Unfortunately, you know as well as I do that that ain't gonna happen. I understand your pacifist ideals and sympathise with them very much. If only we could get people to stop all the greed, aggression, and lusting after power, the world would be so much better as to be unrecognisable.
   But having said all that, let's return to history. The longest periods of stability and relative prosperity have, as I've said, occurred under the rule of empires. (I know .... empires come a very poor second to utopias!) But the most effective empires were those with crushing military superiority. It's not good enough to be invincible; you have to LOOK invincible! Otherwise you get people constantly testing to see how tough you really are; which leads to endless minor wars and the slow haemorrhaging of resources that eventually brings down most empires. Sorry! Too much history .... boring!
   Anyway, what I mean is I think America should look as strong as possible; for all our sakes. But then, like you Phobos, I do ask how much is TOO much.
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You can always count on RobS to come up with a bunch of interesting figures and ideas! And nicely expressed, too ... I could almost imagine myself in the bulldozer!
   I don't pretend to be an engineer and I freely confess to having forgotten most of the mathematics I learned in school, but I'm going to stick my neck out here and ask a question which may brand me as a half-wit!
   In RobS's highly absorbing discourse on the kevlar dome (the 100m hemispherical one), he says:"so the dome will have an upward force on its outer edge of 50,000 tonnes." This is obviously derived from simply multiplying the surface area of the hemisphere, 15,708 sq.m, by the pressure, 3.3 tonnes per sq.m.
   Is this actually correct? Surely some of the pressure is acting sideways; most obviously where the dome approaches the ground. This sideways pressure is balanced by the air pressure pushing in the other direction on the dome wall diametrically opposite. As you climb the dome wall, it gradually becomes less vertical and more horizontal, and the force vectors on the dome become stronger in the upward direction. (Stop me if I'm making a fool of myself!)
   It seems to me, relying on intuition in order to avoid vectors and calculus(!), that the actual total vertical force vector is more likely to be equal to the surface area of the ground multiplied by the pressure. i.e. 7854 times 3.3, or 25,918 tonnes. Any competent mathematician out there should be able to verify this ... or shoot it down!
   If I am not mistaken, the upward pressure on any dome shape will therefore be independent of the actual curvature of the dome and dependent solely on the ground area enclosed.
   Also, if I'm right, we won't have as much trouble preventing the damned thing blowing away like a party balloon!!
   Any thoughts?