Going to Mars To stay - How Much Mass To LEO

John Creighton · 2004-12-17 22:08:54

In many of the recent discussion there was debate over whether Zubrins plan is a one shot deal like Apollo or a stepping stone to lasting exploration and then colonization. In my opinion going to mars to stay means planning in a way that leads to reusability and growth, maximizing the value of human labor both in terms of science and industrialization.

The essence of going to Mars to stay means a permanent presence on mars and it is clear it is cheaper to keep the same crew then doing a crew rotation every two years. The initial goal of going to mars to stay is to lower the cost of a sustained presence on mars until it is feasible to increase the size of the presence on mars. Initially people will be there for scientific reasons given the superiority of humans over robots in many scientific endeavors. They will also be there to test out life support systems and institute resource utilization.

To fully ask how much mass do need to go to mars to stay we must ask what technologies do we significantly need to reduce the cost. The most obvious technology is a refuable nuclear rector. Not having to bring a whole reactor each mission will dramatically reduce the mass that needs to be shipped to mars to sustain a crew there indefinitely. Thus a good starting point to figure out how much launch capacity do we need to stay, might be to ask how big a rocket do we need to launch a refulleble nuclear reactor in one peace. Preferably automatically refualable reactor like the CANDU reactors. I say one peace because it is probably not practical initially assemble one on mars.

GCNRevenger · 2004-12-17 22:42:28

Things high on the list of heavy cargo would be an inflatable perminant HAB dome, which would probobly be fairly heavy if the little Transhab hit about 8MT, that would likly weigh quite a bit. Something fairly large and able to comfortably sustain 12-18 people for years. One floor or two (or three), buried or only partially buried perhaps, with LSS and airlock(s) built in... basically a "base in a box" that would need little assembly to be habitable.

Robotic bulldozer(s) or other marsmovers , probobly Methanol fuel cell powerd, of at least modest size would be need for basic earth moving needed for the dome and for future projects, which will have to be fairly heavy in order to get traction in the low Martian gravity.

An ISRU plant designed for duability and not light weight would be needed with an order of magnetude capacity beyond what is called for in "exploration class" missions and with an extended tank farm for future storage. An additional ancillary reactor to produce Methanol may also be called for to make superior vehicle fuel. Building this device in pieces would be fairly difficult.

And yes, a large ~1.0-2.0MWe reactor capable of being refueled on site with Uranium from Earth, preferably with waste heat recycling, would be needed. This would call for a reactor with a turbine converter, likly Brayton cycle, which would also require various compressors and coolant handling systems. A heavy shielding "blind" over the core to permit astronaut supervision of refueling might be nice.

Oh and a water drilling rig, which may have to sublimate the underground ice with compressed hot CO2, and condense the water out of the product gas mixture. Dust seperation and water fractioning would require some fairly heavy equipment.

These are all things that you wouldn't want to ship in pieces, and would likly be too heavy for MarsDirect. You'd need bigger 40-50+MT payload masses.

John Creighton · 2004-12-17 23:02:22

These are all things that you wouldn't want to ship in pieces, and would likly be too heavy for MarsDirect. You'd need bigger 40-50+MT payload masses

Hmmm 40-50 MT payloads with a 20% mass fraction that means 200-250 MT to LEO, which means 2-3 SDV launches? Of course with a nuclear thermal stage I think 2 SDV launches could get that kind of payload too mars. Of course these are all just estimates. Hopefully those things can be made lighter.

GCNRevenger · 2004-12-18 00:15:27

My estimates might be a little bit high, but I think that the size of these payloads would match well with the NASA DRM style system, which calls for two light HLLV launches to LEO, one with payload/aeroshell/lander and one for the nuclear TMI stage... I doubt that they will be a great deal lighter though, TransHab weighs in at 8MT roughly.. the reactor will be pretty big with its radiators and compressors.. etcetera.

Austin Stanley · 2004-12-18 01:49:24

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

MarsDog · 2004-12-18 06:06:50

In order to firm up various mission details, more accurate satellite survailence is needed. Perhaps appoaching spy satellite resolutions. Then several rovers could confirm underground water, and intact landing of supplies, before human landing.

I see it as a construction site development. Have the robots take all the initial risks. The first few unmanned landings would work out some of the bugs in the plan.

RobertDyck · 2004-12-18 11:58:52

One feature of going to Mars is to reduce mass sent to Mars. I know GCNRevenger keeps arguing against that principle, but it is absolutely necessary. You can't send a modern container ship with millions of tonnes of cargo, rockets just cost too much. The goal is to start with a small scouting/science mission, then send relatively small production equipment that can build heavy, robust facilities on Mars. The final facilities will have to be big and heavy, but the equipment shipped from Earth cannot be. That's the trick, how do you send something small and light that can "leverage" Mars resources to produce final equipment that's robust.

First, we'll definitely need a substantial nuclear reactor. The Mars Homestead project is currently planning on 2 reactors, one for life support, lights, etc, and a second for backup. When not used for backup it would be used to power ISRU and manufacturing equipment. You could plan to use a thorium reactor since MGS found thorium on Mars, but it will probably be a while before we locate a concentrated mineable deposit so plan the initial Mars settlement to use a reactor from Earth.

Next you'll need to harvest resources, the most important one is water. Mars Homestead is planning to locate a subterranean permafrost deposit and use waste heat from secondary coolant of the reactor to melt the permafrost, then pump up liquid water. It'll be salty, muddy water but that can be filtered. "Secondary coolant" is usually water; primary coolant circulates through the reactor and something else (usually water) is boiled with a heat exchanger and piped through a turbine. Primary coolant is exposed to radiation so that ensures the turbine isn't exposed to low-level radiation and if any steam leaks it isn't radioactive. Steam is high pressure before the turbine, but low pressure after. Low pressure steam is piped down into permafrost and return warm water comes back to the heat exchanger. Since the salty, muddy water you pump up will be filtered for drinking water, you don't want to risk a leak in the steam pipe releasing radiation into it.

Another thing is air. Pioneer Astronautics developed the Mars Atmosphere Carbon DiOxide Freezer (MACDOF). It uses the principle that Mars at night is almost cold enough to freeze CO2 into dry ice. A fan blows Mars air through a filter to remove dust (fines) into a canister with freezer coils. CO2 freezes as dry ice frost. When it's full, seal the canister and warm the dry ice to sublimate it into CO2 gas. That will pressurize the canister so you don't need any pump at all. Ingenious design, but doesn't collect anything other than CO2. That's enough to produce fuel for an ERV, but a settlement needs other things. That can be modified by pumping filtered Mars air into the canister, pressurizing to 10 bars, then freeze dry ice. All other gasses will accumulate, including CO. Since slightly more than 95% of Mars air is CO2, that will concentrate everything else 20 times, including CO. That would bring CO to a toxic level. Add a catalyst like the catalytic converter from a car to combine CO + O2 -> CO2. There isn't much O2 in Mars air, but there's more of it than CO. The catalyst will also break ozone into O2, not necessary but it will do so. Actually, NASA developed a catalyst for breathing masks when evacuating a burning building that does this at 20°C, a lot cooler than exhaust from a car. The catalyst at the top of the chamber would be heated to +20°C while freezer coils at the bottom are cooled to 170°K (-103.15°C). Both in one canister will take power, but it'll remove all CO. As CO2 is frozen it'll reduce pressure, a sensor will control a pump to add more Mars air, maintaining 10 bar pressure. Once the pressure doesn't drop any further, close a valve and turn off the pump, but keep the catalyst warm and coils cold. Then when CO levels drop below detection threshold by a sensor, turn off the catalyst heater but keep the coils cold. A thermometer will monitor temperature, when it stops getting colder you're done. Then open a second valve to a "mix gas" holding tank and use a fast scavenger pump to capture as much as possible, reducing canister pressure and pressurizing the storage tank. When that's done close the valve, and open a third valve to a CO2 holding tank. Then heat the dry ice to sublimate it. It only takes -78.5°C to sublimate dry ice so that can use low level waste heat from manufacturing processes or low pressure steam from the reactor's secondary coolant. You don't need to pump out CO2, as it sublimates it'll pressurize itself. There's a trace of water in Mars air, which will freeze as ice in -103.15°C and the -78.5°C won't melt it, so the canister will accumulate a little ice. There isn't much, but it'll have to be melted out a couple times a year.

Mix gas produced: (% by volume)
61.0% N2
36.1% Ar
2.1% O2
0.75% CO2
0.0056% Ne
0.00068% Kr
0.00018% Xe

Just add oxygen to this and you have breathable air.

Or use a sorbent to scrub the last trace of CO2, add hydrogen and burn. Oxygen and hydrogen burn to form water, but nitrogen and hydrogen burn to form ammonia. It won't make enough water to convert all ammonia to ammonium hydroxide, so it'll be anhydrous ammonia. You have to scrub all CO2 out before adding hydrogen to avoid forming CO and water. Ammonia liquefies at -33.35°C and 1 atmosphere pressure, easily separating it. The rest of the gas would be Ar, Ne, Kr, Xe, and any unburned N2. That almost pure argon (>99%) could be used to fill the gap between panes of sealed casement windows. Argon conducts heat more slowly than air, helping to keep heat in; especially important for a greenhouse with its large windows.

RobertDyck · 2004-12-18 12:56:28

I should add, anhydrous ammonia can be mixed with water to form ammonium hydroxide, a liquid nitrogen fertilizer for the greenhouse. Ammonia can also be used for an absorption cycle freezer, so it is a refrigerant. That type of freezer uses heat at one point (from the nuclear reactor) and releases heat at another point, then chills a third point. That runs your freezer from heat alone, more efficient that converting heat from a power plant into electricity to run a compressor. This type of fridge is used on Earth in RVs since it can be run by propane. This refrigerant can be used for the CO2 freezer mentioned above, or refrigerators in the habitat kitchen, or other industrial processes that need a freezer.

Martian Republic · 2004-12-18 17:06:23

The question was:

How do we put a permanent base on Mars?

In the short term, the answer is simple, it can't be done. At least it can't be done in a ten or twenty year time frame of today's date at least. To be able to sustain a base on Mars for a long period of time and limit the exposure to budget cuts on earth, it going to have to be a big base with lots of people on it and even approaching the size of a small city to have the ability to sustain itself. Currently we do not have the technology, infrastructure or even the financial capability to pull it off. We don't have the technologies to launch such an effort, because we would have to be able to ten's of thousands of people to Mars to man it and even nuclear fission could not serve us to get that many people to Mars in a timely fashion. We also don't have the infrastructure to either get people to Mars or maintain them in space or put them down on Mars either and most of it can't come from the earth directly, because it too heavy and would not be practical to do it either. We also don't have the financial capability to finance such an operation either, because it would cost too much to build all the stuff that we would need to make a reasonable long term or permanent base on Mars feasible or doable. Now I'm not saying that it can't be done, but we are going to have to have JFK type mission statement of Grand Government Mission Enterprise that we intend to accomplish, a LaRouche type vision of building city on Mars with power station, Agro/Industrial complexes with mining facilities, FDR type of stating what we intend build on the level that we intend to build it and then figure out how to do once we made the commitment to do it, with an Abraham Lincoln type financial reorganization of the American Monitory system and Money supply. To be able to assemble the resources to attempt a permanent colony on Mars, we would also have to put together a skunk works in space/moon and possibly harvest near by asteroids as they crews past the Earth if they were Iron, nickel or carbon content to assemble the mass we need for our stated goal. We just won't be able to bring enough stuff from Earth in the for seeable future other wise. Unless we can do all this, it not going to happen and even then it will take forty to fifty years to accomplish it even then.

What everybody else has said would make a good start in a first effort, but it would ultimately fail and come up short of our goal to guarantee a permanent base on Mars.

Larry,

Dayton3 · 2004-12-18 18:10:22

Why would you need a refuelable nuclear reactor?

Aren't the nuclear reactors being installed aboard Virginia class submarines capable of running "for the life of the boat" (that is 30 years)?

Could a smaller version of that type of reactor be built?

Even one that ran for 15 years without refueling would probably be worth the trouble on Mars wouldn't it?

idiom · 2004-12-18 18:15:07

Zubrin's plan is built around maximum scouting/science. Thus every two years the base is placed in an entirely different location until someone strikes it lucky and finds a reasonable source of water.

This is why each mission needs to take its own reactor unless you boost it back to Mars orbit to land it somewhere else...

RobertDyck · 2004-12-18 18:16:49

it can't be done in a ten or twenty year time ... we do not have the technology, infrastructure or even the financial capability to pull it off ... ten's of thousands of people to Mars to man it

Um, what! No. At least I am talking about 12 people on Mars constructing the first base. That's after a couple 4-person science missions to scout the geology and test ISRU technology. We do have the technology now. We do have the resources. The primary reason for detailing how it can be done is to kill such grandiose and unjustifiable statements as this. For more details look at http://www.marshome.com]www.marshome.com

Here's my time frame:
• late-2011, launch a robotic sample return mission to demonstrate ISPP
• 2014, it returns with the Mars soil sample
• also 2014, launch the ERV or MAV
• 2016, launch the first manned mission to Mars
• also 2016, second ERV or MAV launches
• autumn-2016, first footprints in red dust
• mid-2018, first astronauts arrive back on Earth
• also mid-2018, second mission launches for Mars
• again mid-2018, launch cargo lander with heavy lab
• still mid-2018, third ERV or MAV launches
• late-2018, second mission lands at same location
• autumn-2020, astronauts arrive back on Earth
• also autumn-2020, launch third mission, base preparation
• again autumn-2020, launch base-size nuclear reactors
• still autumn-2020, launch cargo lander with small mining/extraction/manufacturing equipment
• late-2022, third mission arrives back on Earth
• also late-2022, launch 12-person construction crew in one-way lander, not designed to park in Mars orbit, not designed for return to Earth, does not include habitat. No ERV, long duration stay on Mars.
• again late-2022, launch production scale mining/extraction/manufacturing equipment
• 2023, construction team arrives on Mars

The 12-person construction crew will live in the 3 habitats, 4-person each, left from prior missions only as construction shacks. They will build a permanent base using Mars materials, including a full-size apartment for each crew member.

Martian Republic · 2004-12-18 22:23:39

it can't be done in a ten or twenty year time ... we do not have the technology, infrastructure or even the financial capability to pull it off ... ten's of thousands of people to Mars to man it
Um, what! No. At least I am talking about 12 people on Mars constructing the first base. That's after a couple 4-person science missions to scout the geology and test ISRU technology. We do have the technology now. We do have the resources. The primary reason for detailing how it can be done is to kill such grandiose and unjustifiable statements as this. For more details look at http://www.marshome.com]www.marshome.com
Here's my time frame:
• late-2011, launch a robotic sample return mission to demonstrate ISPP
• 2014, it returns with the Mars soil sample
• also 2014, launch the ERV or MAV
• 2016, launch the first manned mission to Mars
• also 2016, second ERV or MAV launches
• autumn-2016, first footprints in red dust
• mid-2018, first astronauts arrive back on Earth
• also mid-2018, second mission launches for Mars
• again mid-2018, launch cargo lander with heavy lab
• still mid-2018, third ERV or MAV launches
• late-2018, second mission lands at same location
• autumn-2020, astronauts arrive back on Earth
• also autumn-2020, launch third mission, base preparation
• again autumn-2020, launch base-size nuclear reactors
• still autumn-2020, launch cargo lander with small mining/extraction/manufacturing equipment
• late-2022, third mission arrives back on Earth
• also late-2022, launch 12-person construction crew in one-way lander, not designed to park in Mars orbit, not designed for return to Earth, does not include habitat. No ERV, long duration stay on Mars.
• again late-2022, launch production scale mining/extraction/manufacturing equipment
• 2023, construction team arrives on Mars
The 12-person construction crew will live in the 3 habitats, 4-person each, left from prior missions only as construction shacks. They will build a permanent base using Mars materials, including a full-size apartment for each crew member.

I repeat, the question was:

How do we build a permanent base on Mars?

I didn't say that we could not get to Mars with the present technology we have today. But, I did say that we could not build a permanent colony on Mars with the present technology or infrastructure that we have in place right now.

But, the question was not about building a temporary structures on Mars for a short period of time.

If we are going to build anything close to being permanent on Mars it going to have to be big and massive along with being a fairly self-contained units. So what ever we put up there is going to have to be diversified too and we can't do that with what we have right now. Just to get enough people out there to man our base so that we could approach something even close to being permanent on Mars, will be a challenge that we could not meet. Even if we could get a few hundred people on Mars, it would not be enough to constituted being a permanent colony on Mars and even a few thousand might not be enough to do the job, let alone twelve people being considered a permanent colony. Twelve people for colony on Mars and then considering it a permanent colony, that ridicules.

Larry,

RobertDyck · 2004-12-19 00:22:58

How do we build a permanent base on Mars?
I didn't say that we could not get to Mars with the present technology we have today. But, I did say that we could not build a permanent colony on Mars with the present technology or infrastructure that we have in place right now.

Do you want me to quote my whole paper "Aluminum from Feldspar" that I presented at the Mars Society conference last August? I went through the chemical process to extract aluminum from Bytownite, a form a fledspar that MGS found to be 21-26% of average Mars surface. You can't extract aluminum from just any form of feldspar, it needs to have a high aluminum content or it doesn't work at all, but it does work with Anorthite or Bytownite. Since Mars has Bytownite, it works fine.

A byproduct of producing aluminum from bytownite is silica gel. Calcinate that to remove all water, then melt it and you have high purity silica. Add feldspar to form glass. Do you want me to get into more details to make fibreglass?

The iron minerals can be smelted to form steel, carbon introduced as carbon monoxide from Mars air.

You can also make portland cement for concrete or mortar. Bricks, all forms of plastic. I could give you step-by-step chemical processes to make every plastic except fluoropolymers from Mars resources. Fluoropolymers require fluorine; it does exist but we haven't found a concentrated deposit yet.

Remember I was the ISRU guy for the Mars Homestead project? I do know how to make construction materials from Mars resources.

Commodore · 2004-12-19 00:41:58

How do we build a permanent base on Mars?
I didn't say that we could not get to Mars with the present technology we have today. But, I did say that we could not build a permanent colony on Mars with the present technology or infrastructure that we have in place right now.
Do you want me to quote my whole paper "Aluminum from Feldspar" that I presented at the Mars Society conference last August? I went through the chemical process to extract aluminum from Bytownite, a form a fledspar that MGS found to be 21-26% of average Mars surface. You can't extract aluminum from just any form of feldspar, it needs to have a high aluminum content or it doesn't work at all, but it does work with Anorthite or Bytownite. Since Mars has Bytownite, it works fine.
A byproduct of producing aluminum from bytownite is silica gel. Calcinate that to remove all water, then melt it and you have high purity silica. Add feldspar to form glass. Do you want me to get into more details to make fibreglass?
The iron minerals can be smelted to form steel, carbon introduced as carbon monoxide from Mars air.
You can also make portland cement for concrete or mortar. Bricks, all forms of plastic. I could give you step-by-step chemical processes to make every plastic except fluoropolymers from Mars resources. Fluoropolymers require fluorine; it does exist but we haven't found a concentrated deposit yet.
Remember I was the ISRU guy for the Mars Homestead project? I do know how to make construction materials from Mars resources.

The question is, just how much hardware do we need to make all that stuff in reasonable quanities?

RobertDyck · 2004-12-19 00:49:48

To see floor plans and images of the permanent base http://www.marshome.org/images/viewer.p … 4#tn]click here. The top row are images produced by the Mars Homestead architect, Georgi. (His name is pronounced "Yorgi".)

RobertDyck · 2004-12-19 00:52:07

The question is, just how much hardware do we need to make all that stuff in reasonable quanities?

That is the point of the Mars Homestead project. If you want to help, volunteer.

Austin Stanley · 2004-12-19 01:37:17

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.

MarsDog · 2004-12-19 05:32:51

http://www.imdiversity.com/villages/nat … sp]Toshiba mini-nuke

Nasa is short of funds;
Christmass hamper, size of a http://www.google.com/search?q=toshiba+ … =utf-8]big spruce tree, from Japan would help.

GCNRevenger · 2004-12-19 12:45:51

"One feature of going to Mars is to reduce mass sent to Mars. I know GCNRevenger keeps arguing against that principle, but it is absolutely necessary. You can't send a modern container ship with millions of tonnes of cargo, rockets just cost too much. The goal is to start with a small scouting/science mission, then send relatively small production equipment that can build heavy, robust facilities on Mars. The final facilities will have to be big and heavy, but the equipment shipped from Earth cannot be. That's the trick, how do you send something small and light that can "leverage" Mars resources to produce final equipment that's robust."

Impossible. Absolutely, completly, entirely impossible. It is a chicken/egg problem, you can't go making huge quantities of bulk materials to build a base with unless you have heavier lift to send the factories of nessesarry scale! You keep on going on about the chemistry of producing building materials, but I don't think you have the foggiest notion of the factories or the required equipment to make materials on any kind of scale. Tons quantities, not kilograms, will be required to build a base of signifigant size. You take Earthly factories completely for granted,

No concieveable reloadable multimegawatt nuclear reactor that is light-liquid or gas primary cooled will fit MarsDirect style hardware, even a small I don't think this can be done, making it refuelable will greatly increase the core mass because of the divisions in the pressure vessel required (see Candu), superheavy duty turbines/compressors, and large low-temperature radiators. It would be hard enough to cram the dinky 300/100kWe throw away Brayton style Prometheous reactor, and it measures in the region of 10-15MT or so. The little SP-100 reactor, which is several times too small and is purely a throw-away high-temperature piece of equipment, weighed in around 6MT... and thats no shielding, no carrier, and no waste heat system.

An Aluminum/Glass/Iron smelter will be a very heavy piece of machinery if it has to be able to crush and sort the ores, process them and refine them, and finally to CAST pieces of useful size. This is not going to be easy, it will by nessesitty be very heavy because of the high forces to deal with semi-molten metal and the thermal resistance needed. This is to say nothing about the milling machinery/workshop either.

So would a bulk polymer plant, which is a whole different animal then an ISRU methane/oxygen/water plant, which would require a great deal of chemical-cooking hardware to produce anything other then simple Alkyl polymers. I don't think you comprihend the amount of trouble it would be to make anything else, like Polyesters and Polyamides (alkyl and aromatic), on any kind of scale. Do you even know the chemistry behind them?

I think you are also vastly overstating the availability of water when we set up shop, it won't be easy to get it out of the ground in signifigant quantities, and it will always be precious commodity. Recycling and hoarding every drop and gram of Hydrogen in whatever form will be paramount concern for the whole first century after landing, so get the idea of concrete out of your head. Its probobly too precious to waste on bulk polymers most likly either... Earth on the other hand, has no such shortage.

Martian bulldozers will also be pretty heavy since they will have to reclaim the water in their exhaust and will have to have more mass to produce the same force because of the lower gravity. So would a water drilling rig, NASA DRM estimates that the multikilometer-scale drill alone would weigh ten tones, and that isn't counting the tractor for it or the water mining system or any of the plumbing and so on.

And finally, an ISRU plant with enough capacity to make Methane and LOX for a Martian RLV capable of a dozen "Delta-II up/Atlas-V 55X down" scale flights a year or support a base of 12-18 will have to be quite large, which is what will be needed to support a "beyond McMurdro" phase. Certainly more then a few tons for a little explorer-class operation, especially with surface vehicle fuel demands.

Larger payloads will be required then what MarsDirect offers in order to send factories to make materials on any useful scale. 25MT payloads aren't going to cut it and it won't be practical to break down into pieces. It would cost a bundle for two MarsDirect shots anyway... Ssince MarsDirect is inherintly too small to even perform scout missions, a NASA DRM "50MT" sized mission will be employed anyway. Use a solar-ion tug to eliminate the nuclear TMI stage could save a bundle on rockets too.

RobertDyck · 2004-12-19 13:18:44

Martian bulldozers will also be pretty heavy ... will have to have more mass to produce the same force because of the lower gravity.

That point I must object to. The lower gravity means lower weight that must be lifted for a given mass (mass * gravity = weight) so less force is required to lift a bucket full of soil. That means a lighter front-end loader.

Aluminum extraction: remember I said 21-26% of Mars soil is bytownite? We don't have to crush it, just scoop it up and process. Since you're a chemist, would you be willing to help determine chemical ways to separate? The paper I presented at the Mars Society conference started with the assumption of pure bytownite, but soil isn't pure. I breezed over differential dissolution; this dissolves in water and can be washed away first, that dissolves in hydrochloric acid, this other won't be dissolved so left behind. I know how several minerals will respond, but I don't know them all. Would you be willing to work on constructively developing ISRU equipment?

Grypd · 2004-12-19 14:11:23

Bulldozers rely on there weight and grunt to be able to scoop. For the front end of a Bulldozer to actually bite into the soil relies purely on the force downwards of their mass and gravity. So it is impossible for them to be scaled back in weight. If we find that Mars like the Moon has the regolith fairly loose for about 15cm then being very compacted it becomes a different matter.

If this is the case then a Martian Bulldozer to be able to function will have to be a lot heavier to be able to do the same amount of work. On the Moon Bulldozers will likely not work and this may be the case on Mars too. The gravity element will simply not be powerful enough.

Of course there are other ways to be able to scoop Regolith up like Draglines or even rotating brushes and it can allways be done by a lot smaller digging implements. But only going to there and trying it out will we find out.

edit
And dont forget the possibility of permafrost. in that case its a whole different matter this material will be so hard it becomes time for a little bit of a blast.

Martian Republic · 2004-12-19 21:57:54

it can't be done in a ten or twenty year time ... we do not have the technology, infrastructure or even the financial capability to pull it off ... ten's of thousands of people to Mars to man it
Um, what! No. At least I am talking about 12 people on Mars constructing the first base. That's after a couple 4-person science missions to scout the geology and test ISRU technology. We do have the technology now. We do have the resources. The primary reason for detailing how it can be done is to kill such grandiose and unjustifiable statements as this. For more details look at http://www.marshome.com]www.marshome.com
Here's my time frame:
• late-2011, launch a robotic sample return mission to demonstrate ISPP
• 2014, it returns with the Mars soil sample
• also 2014, launch the ERV or MAV
• 2016, launch the first manned mission to Mars
• also 2016, second ERV or MAV launches
• autumn-2016, first footprints in red dust
• mid-2018, first astronauts arrive back on Earth
• also mid-2018, second mission launches for Mars
• again mid-2018, launch cargo lander with heavy lab
• still mid-2018, third ERV or MAV launches
• late-2018, second mission lands at same location
• autumn-2020, astronauts arrive back on Earth
• also autumn-2020, launch third mission, base preparation
• again autumn-2020, launch base-size nuclear reactors
• still autumn-2020, launch cargo lander with small mining/extraction/manufacturing equipment
• late-2022, third mission arrives back on Earth
• also late-2022, launch 12-person construction crew in one-way lander, not designed to park in Mars orbit, not designed for return to Earth, does not include habitat. No ERV, long duration stay on Mars.
• again late-2022, launch production scale mining/extraction/manufacturing equipment
• 2023, construction team arrives on Mars
The 12-person construction crew will live in the 3 habitats, 4-person each, left from prior missions only as construction shacks. They will build a permanent base using Mars materials, including a full-size apartment for each crew member.

As far as answering your challenge to my claim that it needs to be big, I will defer to GCNRevenger answer. He answered it sufficiently well in that you need both size and the infrastructure to make what you propose work for what you want to accomplish on Mars.

You can show us a model and it good that you have a plan and I have no problem with that and that even a starting point for creating a permanent Mars colony. But, even it you could get your Aluminum in small quantities, and I stress small quantities, it going to be labor intensive and it not being either machined into a finished part nor does it deal with other things that need to be products, which are also labor intensive too. To put together a major factory down here, it takes 5 to 6 years to do it and we don't have to worry about the transportation to Mars to do it and it doesn't have to be completely self-contained even after it been built either.

For example:
1. It take six month build the buildings.
2. It would take another six to twelve months to buy all the machines and set them into place. The reason it take so long to do it is, you have to dig a foundation for each major machine that you put in. There sometimes referred to as statues, because you have to dig ten to fifteen foot deep and then put six foot layer of concrete with iron rods crisscrossing it and welded together. They did several of those where I use to work. One of the smaller ones was fifteen foot across and about thirty foot long and about ten foot deep being filled up with about six foot of concrete. It took eight to ten concrete trucks to fill it up to where they wanted it. I watched them do that for four machines of the same size over about a ten year period. The biggest one they laid down was twenty foot wide and about hundred and fifty long bed and about ten foot deep with six foot of concrete in the bottom for the foundation. They had ten cement trucks for this project and they made four or five runs per day for two days. So what my point you might say? My point is, this is all NC equipment and not conventional mill or lathes. So anybody that thinks that there going to go to NC equipment so that they can get away from having people on either the moon or Mars needs to consider this problem. Even if you go with smaller NC equipment so you don't have to lay down as big a foundation as I'm talking about, you will still have a foundation problem that you will have to deal with before you even start setting your NC equipment or robots in some cases. Let just say for the argument sake that it going to take one and half to two year to assemble major factory down here on Earth without the transportation problem to get to Mars.
3. Now it takes another two to three year to train your employee and get them working together to produce something fairly efficiently and be able to make a decent profit on what they produce without generating too much crap in the process.
4. Now keep in mind that there still not producing everything they need for the product that there producing. They order there casting from a foundry. They off load some of the machine process to other manufactures in sub-contracts. They have suppliers for carbon inserts, tool, fixtures, maintaince, etc. If they need tires, they go to a tire manufacture and don't produce it themselves. With many other sub-contractors and suppliers beside.

My point, this Martian Colony of twelve people does not have this kind of support nor could they spare the man power to do something like this and neither do have they enough diversity to do it either because of there small number. On paper you can make anything happen, but in the real world, what your talking about doing is just not going to happen.

Larry,

GCNRevenger · 2004-12-19 22:18:23

"Bulldozers rely on there weight and grunt to be able to scoop. For the front end of a Bulldozer to actually bite into the soil relies purely on the force downwards of their mass and gravity."

So would a front-end loader if it were trying to cut into the ground. Or a backhoe that uses its weight to cut into the ground.

I could dig up the synthesis and reactants needed if you have a specific polymer you'd like to make though my knowledge of inorganic (minerals) is limited. I could make a stab at it.

SpaceNut · 2004-12-20 06:09:36

Ok so I am late jumping into this topic long weekends with family and such. Thanks for posting it thou John:

Where do I start, in order to know the down mass we must detail the needs for the given size crew and the stay time frames plus a buffer zone on consumables and this includes energy needs.

Energy needs are not only for science, lighting, Heat and other uses. So what is the exact quantity of the supply that we can send and what forms of creation can be supplied for the safety of the crew(solar, nuclear..).

If nuclear we can detail out what it would provide and we know how much it weighs but what happens when it is not working for any reason or that it must work at a reduce power available rate. What them would the crew do for there energy needs?
Multiple power sources are needed and they each must be capable of at least half of all power requirements or needs each or more.

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