New Mars Forums

I guess this is more of a cultural issue, but I (and I belive the majority of American's) live to work.  No matter what the job is, most people here feel a need to be working, to be doing something for a vast majority of their lives.  I can certianly vouch for myself, my parents, and the majority of the people I know.  This is also backed up by work statistics, Americans work more hours on average than nearly everyone else in the world, including most so called "developing nations."

Not trying to bring jingoism and what not into this, but I wanted to point out an important cultural diffrence.

I would point out that LSS work on the ISS, which is resupplied every month or so, may not be all that applicable to those of a Mars mission which has to work for many months to years without resupply.  Likewise other critical issues such as radiation shielding would not addressed as well.

If you want a space mission with some usefull mars spin-offs, I think the moon is the place to look, as it requirments are similar.

Well obviously a permanent city of mars is quite some ways away, but a Martian McMurdo that GCN, RobertDyck, and I propose is certianly the next step after an intial series of exploration missions.  The only way a permanent presence is going to happen on the planet is a gradual build up of people and resources on the planet, because, as you point out, if we were to try and carry the costs of it all at once it would be far to great.  But spaced out over time, it is possible.

As for complaints that the mass of the components is to much, I have to disagree.  For the most part, the mass of the expansion equipment falls under 20MT, within the throw weight of the Mars Direct plan.  The only tricky item is the heavy duty nuke, which we (mostly) all agree is an absolute necessity.  I'm all for leveraging martian resources, but I think some realisim in the approach is necessary.  Developing metal and plastic refining techniques on mars is critical, but it will be VERY difficult.  Not something that I would put my focus on at the start, certianly not making my mission dependant upon it for it's success.  I think this would be a good topic for another thread however.

The reason I advocate a refuelable reactor are three-fold.  Firstly to keep it's weight down.  For a large nuclear reactor it's fuel is a not-insignifigant fraction of it's weight.  This weight increases as you increase the amount of time the reactor can operate before being refuled.  Secoundly, a Mars Reactor may very well be called to sever well beyound the 15-30 year period a submarine is expected to.  The build up of a mars base will be a very slow operation, and the fewer nuclear reactors we have to send, the better.  Much better to simply have to send the fuel for the thing instead of a whole new unit.  Thirdly is the issue of safety.  A decomissioned nuclear sub can safely be complety unfuled and scraped, but on mars dealing with large amount of radioactive waste and potentialy radioactive parts at one time will be difficult to impossible, but leaving the reactor just sitting there is  hazard as well.  Better instead to deal with it's parts and spent fuel one small more manageable bit at a time.

I agree with most of what GCN says with a couple exceptions.

Without a doubt the 2 most important commodities on mars are power and water.  So GCN is right, in building a permant base you need to find a source of water, and you need a large scale heavy duty nuclear reactor.  I think 1-2MW may be overkill at the start, but it does gives you pleanty of growing room later when you want to do more energy intensive stuff like smelting in an electrofurnace.  Water is not so easy but finding a pleantiful reliable source will be a huge benifit.  I think GCN is probably right when he recomends a melting the permafrost with a drilling rig.

Taking care of water and power eliminates two of you heaviest and most redundent componets that you would import from Earth.  That is those little nukes and all of the martian stay LSS requirements and the rocket fuel for the assent and perhaps TEI phases of flight.  It should also give you pleanty of methanol and methane to power your rover with.

As for a heavy duty ISRU I am doubtfull as to how much one of these realy needs to be scaled up.  The Sabatier process is dead simple, and is exothermic so requires relativily little energy to get going (in fact, on mars you would probably be more worried about getting rid of the excess heat).  The big limiting factor is the electrolisis of water, which is fairly energy intensive.  Scale up the rate at which you can electrolise the water, and you will speed up the rate at which you can produce your other by-products.  I guess some additional equipment would be needed, but not that much, mainly extra tanks and electrolisis units.

As for earth moving equipment, alot will eventualy be required, but what and how much you actualy need at any one time depends upon what you actualy want to do.  Also, these machines can usualy serve more than one duty.  For example, you bulldozer could also have your back-hoe on the other end.  The dozer/backhoe is your primary requirment, after which you would probably want a dumptruck and a crane, and eventualy another dozer.

As for habitation, I do not think the large dome GCN calls for will be necessary or practicle in the short term.  Alot of ground work would be required to set it up, and then you have to bring in all the furnature, partions, equipment, and LSS to furnish it with.  All in all quite a lot of mass and work.  But you get fairly little pay-off for it.  A big dome is less safe then multiple distributed facilites, offers no more protection from radiation, is probably generaly less space efficent, and most importantly does not eliminate the necessity of a hab during the transit portion of the flight.  Since you are going to have to use a hab for the 6 month journey in, why not make use of it on the base.

I would use smaller domes for agriculture work though.  Lots of earth work is still required, but much fewer furnishings most be imported, and the LSS requirments are not as intense either.  Along with a green house, an ammonia fertiliser plant would also be necessary.  The Haber process is not to disimilar to the Sabatier process, simple and reliable, if you have the nitrogen (not a given) the machinery shouldn't mass that much.

After you have food, power, and shelter taken care off the next items are on your list become much more difficult.  The refining and utilisation of metals and plastics on mars is certianly very possible, but the machinery is much more special use and very heavy.  Since there is little call for mass production, you would have to bring alot of mold for everything you wanted.  These are fairly heavy, so you might as well end up bringing the real thing instead, in which case you might as well have brought the real thing.  So instead of casting, automated milling machines would probably be used.

Anywhere here is my priority list and estimated mass amounts (very rough).
#1. 2 MW refuleable nuclear reactor 50MT+
#2. Water extraction system 20MT? (depends on what exactly is eventualy needed)
#3. Expanded ISRU plant (water electrolisis, methane and methanol production) 5MT
#4. Dozer/Backhoe 5MT
#5. Dumptruck 2.5MT
#6. Crane/Dredge 5MT
#7. Air Liquification Plant 20MT
#8. Greenhouses 5MT each
#9. Ammonia Plant 2.5MT

The solution for composit tanks would be a thin coating of a more corrosion resistant material, in this case probably titanium or zincronium.  Although I'm not sure how exactly you would deposit such a coating onto the inside of a composit tank.  Conventional plating techniques obviously will not work on non-metals.

That said most chloroflourocarbons (like Teflon and Kel-F) are okay for working with Perchloric Acid that is fairly concentrated.  Heck, even some common plastics like polyethylene and polypropylene could be used.  But that doesn't necessary apply to anhydrous (>85% concentration) perchloric acid, and like GCN when the stuff is heated it is dangerously reactive/explosive even.  I'm not sure if Kel-F could stand up to it, you would have to test it.

Hmm, I had not considered the possiblity of pad accident.  That could be bad, very bad.  Liquid F2 would burn with, well pretty much anything, even traditional exstinguisher gases like CO2, Halon (a chloroflurocarbon), and chemical salts would burn.  It would be pretty much unextingusihable, because Flourine is such a strong oxidizer.  And of course, you wouldn't want to breath flourine either, and all the burn products would of course also be very toxic (just about everything associated with flourine is toxic).

But it still might be worthwhile on Mars.  Flourine shouldn't be that (flourspar should exist on Mars) hard to find, and you would need it for other purpouses any ways.  And it's toxicity/reactivity wouldn't be as dangerous in Mar's cold low-pressure atmosphere.  Just something to think about.

Well if you introduce a HLLV that replaces the shuttle, it's increased launch capacity would improve the economics some what.  Instead of spending ~1billion for 20MT in orbit you would be paying ~1billion for 80MT+ of payload.  This is an improvment over the old Saturn V which was nearly 3 billion (inflation adjusted) for the same amount.

Not to say that some staff reduction is not a good a necessary thing.  Certianly those persons who's job it is to inspect and refit the shuttle for flight will no longer be necessary if it is replaced with a HLLV, although they may just transfer over to the CEV.

I'm sorry if I misunderstood what you proposed.  It was my understanding that you were thinking about shaping an individual strand in such a fashion.  Please forgive me for being a little short tempered, some of your earlier inqueries have reduced my patience.

CM Edwards, in my statment I was refering specific to examining the phenomenon of molecules moving within a carbonnano tube.  For such a stituation all of what I said is certianly true.  But in a more general sense my comments are motivated by a general misunderstand of what the nano-scale relm realy is and what it entails.  Alot of people have got this weird concept in there head (propigated by Eric Drexler, Ralph Merkle and others) that you can slap molecules around and build gears and what not on a nano-scale just like you could on a macro-scale.  But this is foolishness, the chaotic nature of the realm makes such machines impossible.

Nanotechnology IS real, I am probably going to focus my career in chemistry around it in some fashion.  But it is not normal physics just scaled down, it is something else entirely.  Real nanotechnology is pretty much indistinguishable from normal chemistry except that it's products are chemicals usefull on the nanoscale.  It is not "grey goo" or "miracle utility foam" that SF loves to talk about.

I don't think you truly understand the meaning of the word "nano" in nano tubes.  Things on the nano scale are small, REALY small.  Realy, realy, realy small.  And at such extreaml small scales, things work really diffrently.  The physical forces and concpets that dominate in our macro scale universe such as gravity are irrelevent when applied to the nano-scale.  Other forces such as ion attraction, hydrogen bonds, dipole-dipole interactions, and van der Waalss forces, are much more relevent.  Most of our physical measures such as distance, velocity, momentum, pressure, and even position are useless in this enviroment, replaced with temperature and concentration. Also things happen on a MUCH more rapid pace then they do in our macro universe.  Chemical bonds are formed and broken faster than you could possibly precive it happening.  And everything is in constant random (brownian) motion in all directions at speeds that if they were scaled up to the macro would be more like those of spaceships then man.

To put it simply, things don't work on the nano-scale like the do in the macro-scale.  Diffrent sets of physical forces predominate and a entirely diffrent set of conditions exists than does on our level.

I think one of the big problems with reusable rockets is that they focus to much on re-using the upper stage and not enough on re-using the lower stages.  The lower stages are much more massive and thussly genearly more expensive, if anything it makes more sense to reuse them then it does the upper stages.  Likewise the lower stages genearly undergo much less stress then the upper stages, they never go into space and thus they never have to deal with re-entery.  The problem with this is that the vertical geometry of space-flight has always made designing the lower stages to be recapturable more difficult.  I don't have an easy answer to this, but I think it is something that should seriously looked at.  It makes no sense to waste all the engines and tankage on a lower stage which never realy leaves earth in the firstplace.

As for scramjets, I am hopefull, but I think it is still way to early to start placing any bets on these.  We are relay only just getting started here.  There max velocity is only Mach 12 or so anyways so certianly it will have to switch into some other mode of opperation or be augmented somehow to achive orbit.  You also have the problem (as someone else pointed out) that you are generating all this horizontal velocity inside the atmosphere and so making alot of drag to go with it.  I still hold the hope that a scramjet might be usable as some sort of reusable upper stage though.

NTR were discussed earlier, and I am with GCN on this one.  It may not be possible to generate the necessary thrust for a lower stage, but they should definetly work fine for an upper stage, and they will certianly be deployable before scramjets ever will.  Making them reusable would be tricky however, as you have to service a nuclear reactor.  I am optimistic about the material concurns though.  Materials are something you can test reliability for pretty succesfully, unlike complete launch systems which have a tendency to fail in new and unusualy ways.  In terms of the cermaic designs one of the things I know they have been working is making them with regular microfactures already built in so that they fail less often and in a more regular way.

As for maglevs and railguns, I just don't think they are going to work.  You might be able to set up some sort of railgun-scramjet-rocket system that would get small satilites into orbit, but you would never deliver people or other large cargos that way.

Heh, well as it seems to be your idea, you should have the honor of naming it.  Jupiter is a good one though, IMO.

If you have geo-thermal heat, why bother with a kilometer tall tower in the first place?  Just use that to power your turbine in the first place.

Again it's not so much an issue as to if you might be able to use it to generate power.  There are a LOT of ways to generate electricity and heat, you could put out a realy long anttenna and gather radio waves for example.  The issue is not all of these methods are practicle, and building a kilometer plus tower on Mars certianly qualifies as impracticle, IMO.