50 years after...

Glandu · 2012-06-01 02:55:31

I think I have to side on Impaler's side, on this one. For mechanical elements, there's a lower limit of price. Prices of cars or planes are showing stagnation since decades. Prices of launches are falling down strongly those days, because they are still faaaar above that minimum cost(and high prices/costs had no incentive to go down until recently). Yet, we will meet a limit, sooner or later.

Even more for machining. I know there's been impressive things done with dynamic extrusion. Yet, it's not enough to build an industrial base. You need good steel, good tools, and good power. Solar power, despite its qualities, lacks punch - especially so far from the sun. Nuclear power has other problems.

For scaling up, you need a lot of steel. Why? Let's begin by the beginning. Scaling up population means scaling up housing & food production(and other things, that I will consider minor even if they are not). For housing & greenhouses you need a lot of transformed materials. For them yuo need a lot of raw materials plus a lot of machining & other transformations.

For getting a lot of raw materials you need mining. Mining does not scale down well. The ground is hard, and only big machines with a lot of strong steel using a lot of power can manage it decently. You won't get anywhere with medieval-style pikes & shovels.

For transforming all that into high-quality finished elements, you need machine tools. For wich, usuallt, quality comes with size. An heavier, bigger machine suffers less from vibrations, is more rigid, and will overall machine more accurately. More power also meansmore speed(and speed control), & therefore ability to have better surface conditions. Surface conditions are very important in a planet that will not yet be terraformed.

el_slapper. I'm imitating Rune, now. But I know when not to be too optimistic.

louis · 2012-06-01 06:36:37

Glandu wrote:

I think I have to side on Impaler's side, on this one. For mechanical elements, there's a lower limit of price. Prices of cars or planes are showing stagnation since decades. Prices of launches are falling down strongly those days, because they are still faaaar above that minimum cost(and high prices/costs had no incentive to go down until recently). Yet, we will meet a limit, sooner or later.
Even more for machining. I know there's been impressive things done with dynamic extrusion. Yet, it's not enough to build an industrial base. You need good steel, good tools, and good power. Solar power, despite its qualities, lacks punch - especially so far from the sun. Nuclear power has other problems.
For scaling up, you need a lot of steel. Why? Let's begin by the beginning. Scaling up population means scaling up housing & food production(and other things, that I will consider minor even if they are not). For housing & greenhouses you need a lot of transformed materials. For them yuo need a lot of raw materials plus a lot of machining & other transformations.
For getting a lot of raw materials you need mining. Mining does not scale down well. The ground is hard, and only big machines with a lot of strong steel using a lot of power can manage it decently. You won't get anywhere with medieval-style pikes & shovels.
For transforming all that into high-quality finished elements, you need machine tools. For wich, usuallt, quality comes with size. An heavier, bigger machine suffers less from vibrations, is more rigid, and will overall machine more accurately. More power also meansmore speed(and speed control), & therefore ability to have better surface conditions. Surface conditions are very important in a planet that will not yet be terraformed.
el_slapper. I'm imitating Rune, now. But I know when not to be too optimistic.

Really, Glandu, this won't do. What do you mean solar power lacks punch? I've never heard anything so ridiculous in all my time here. Solar power can deliver as much punch as you like. Mars is further away but it has a lot less cloud cover, so the difference is not as great as you might think.

The rest of the post seems just as fanciful.

For one thing you don't need steel for housing. There are billions of people who live in homes on Earth that have virtually no steel in them. Hadn't you noticed that? Zubrin showed many years ago how you could make pressurised habs on Mars with ISRU materials - basically Mars bricks. For bricks the most important thing you need is heat - and solar power can provide that.

You comments are complete wide of the mark on mining. Small scale mining has been around since forever and continues to this day. There are plenty of tiny gold mines on Earth. There used to be plenty of coal mines.

You don't need a huge industrial infrastructure for farming on Mars. Farm tools can easily be fashioned. They don't necessarily need to be made from steel. You can use bamboo, ceramics and other materials. Initially we may need to use hydroponics but gradually we can replace that with soil based agriculture. We can manufacture soil on Mars, grinding down rock, adding a bit of sand, some minerals from Mars, some liquid manure from Earth and faecal matter from the humans on the planet. We will of course be careful to recycle nearly all organic matter back into agriculture.

Remember we are talking here about a pretty small community - max. 10,000. In terms of food stuff, they need about 15000 kgs (per day) of foodstuffs. We aren't talking about millions of tonnes. It's still challenging as Mars has no natural conditions for agriculture (apart from sunlight) and it will be expensive, but Mars will be generating huge revenues and the expense can be covered.

Well you said it - quality usually is matched with size in conventional industry on Earth in terms of machine tooling. But there is no necessary link. You can weigh down small lathes with ballast, so there is no reason that the bench itself should be unsteady.

Of course we will import the lathes to begin with. But with those lathes we can make nearly all the tools we need in everyday life on Mars.

I used to be sceptical about plastics production on Mars. But having seen the latest 3D printers on Earth, I think even there we can make progress. We simply need to find ways of producing the plastic feed, how to make it from hydrogen and carbon on Mars.

Overall, I think you make teh common mistake of assuming Earth economics apply on Mars. They don't. There, the key factors are launch and transit costs and also constraints on the amount of tonnage that can be brought in.

Last edited by louis (2012-06-01 12:31:41)

Rune · 2012-06-01 06:42:07

You all know we are talking fifty years after the first landing here, right? I mean, 25 launch windows. I see a lot of wild optimism here, thankfully tempered by some. No freaking way a self sufficient colony numbering in the thousands is up and running by then, IMO. Try a hundred years, and maybe we are talking. Maybe, just maybe, the exponential population growth is starting about this time. I mean, maybe there are permanent residents by then, a few at most. But most of the money going to Mars in those days is going to be from the government, and for scientific/prestige reasons, I expect.

Eventually, yes, all populations have a geometric growth if the resources are available to do so. Plain mathematics. But establishing a seed for that is going to be much more difficult than some optimists realize, like Glandu, Impaler and others are saying. Maybe we'll get around to trying that 50 years after the first landing. I can guarantee you that is not a given, but if we are being optimistic I'll grant that. But even if the best of cases, by this time frame we are beginning to build in Mars the truly large-scale civilization blocks that will enable that growth, not in the middle of the process. Factories (manufactured with as much martian mass as you can, but mostly imported in terms of cost and man-hours to build them) capable of sustained growth and meaningful production will be coming online by then, and the reusable system that gets people there and back will be entering its mature stage of operations and expanding. The construction methods for building on Mars will start to look something close to standard. It would be a miracle if the legal mess of colonizing another planetary body is solved by then, but that kind of thing always trails after reality anyhow.

The most I would say about this time frame, is that by now the picture should be much more clear as to how the colonization effort will proceed. Most of the important questions about that will be able to be answered by this time, and the next step will be decided then and only then. I would very much like to be there to see that!!

Rune. Imitation is the best form of flattery.

louis · 2012-06-01 14:28:41

Rune wrote:

You all know we are talking fifty years after the first landing here, right? I mean, 25 launch windows. I see a lot of wild optimism here, thankfully tempered by some. No freaking way a self sufficient colony numbering in the thousands is up and running by then, IMO. Try a hundred years, and maybe we are talking. Maybe, just maybe, the exponential population growth is starting about this time. I mean, maybe there are permanent residents by then, a few at most. But most of the money going to Mars in those days is going to be from the government, and for scientific/prestige reasons, I expect.
Eventually, yes, all populations have a geometric growth if the resources are available to do so. Plain mathematics. But establishing a seed for that is going to be much more difficult than some optimists realize, like Glandu, Impaler and others are saying. Maybe we'll get around to trying that 50 years after the first landing. I can guarantee you that is not a given, but if we are being optimistic I'll grant that. But even if the best of cases, by this time frame we are beginning to build in Mars the truly large-scale civilization blocks that will enable that growth, not in the middle of the process. Factories (manufactured with as much martian mass as you can, but mostly imported in terms of cost and man-hours to build them) capable of sustained growth and meaningful production will be coming online by then, and the reusable system that gets people there and back will be entering its mature stage of operations and expanding. The construction methods for building on Mars will start to look something close to standard. It would be a miracle if the legal mess of colonizing another planetary body is solved by then, but that kind of thing always trails after reality anyhow.
The most I would say about this time frame, is that by now the picture should be much more clear as to how the colonization effort will proceed. Most of the important questions about that will be able to be answered by this time, and the next step will be decided then and only then. I would very much like to be there to see that!!

Rune. Imitation is the best form of flattery.

No, I don't accept the 25 launch windows limitation. What exactly stops us transiting at sub-optimal times? As far as I can see, once you have your transit craft in place, it's really a matter of fuel.

Anyone would think I was predicting a civilisation of millions. All I was suggesting was a figure between 1000 and 10000 and maybe closer to 10000 than we might expect.

For a community of 10,000 we are talking about an average of 200 per annum transiting to Mars. We might be building up to a fleet of say 35 craft launched over several decades, each able to carry 10 people to Mars. Maybe the average length of stay on Mars will be in the region of 3 years. [EDIT: Schoolboy error on that calculation. Of course the key issue is how long people stay on Mars. I doubt there will be many lifetime stayers in 2070, so most people will be coming back to Earth. If the average stay by then is 5 years, you probably need something more like 200 craft - a significant increase over my previous estimate. Makes me think we will need to invest in creating superliners to ferry people between Earth and Mars, carrying more like 100 people than 10. ]

You're talking as though the only way to produce something is with a huge mass production factory. You're also talking as though Mars will be a high consumption society. I don't think it will in terms of private consumption. For many decades it will be a fairly frugal sort of society - in the sense that people won't be buying huge amounts of clothes, paper, carpets, curtains, furniture and so on - the sorts of things that consume so many resources on Earth. The production will go on the essentials of life: habitat construction, energy production, plumbing, wiring, lighting, agriculture, transport.

You don't need a sophisticated vehicle to get from A to B.

The First Five Decades on Mars will be a time when the settlement's energies are focussed on quite a narrow range of essential tasks:

Energy production (using imported PV panels but also ISRU reflectors)

Water sourcing

Mining for iron, aluminium, calcium, basalt, silica, etc

Atmospheric separation and electrolysis of water.

Rocket fuel production.

Steel production

Ceramics production

Plastics production

Artifical soil production

Food agriculture

Materials agriculture (e.g. bamboo, flax)

Farm tools manufacture

Electric motors manufacture

Electric light bulbs manufacture

Basic vehicles with wire wheels

Brick kilns

Glass production

3D printing of plastic parts

It's not that long a list. It is focussed on the big mass objects (food, habs, electric motors etc) that are extremely expensive to import from Earth. But there will be many imports from Earth still e.g. medicines, computers, fertiliser concentrate, space suits, 3D printers, copper cabling, lathes etc.

From 30 years on the Mars community may be able to manufacture basic rockets for launch to LMO - similar to the Armadillo spacecraft perhaps.

A final point: remember it is Musk who is leading the drive to Mars. And Musk is very clear in his own mind that he wishes to establish humans on Mars. There is only one way to do that: through
ISRU and the creation of an appropriate scale industrial infrastructure. I think Musk will be putting a lot of effort into getting this right.

Louis: A mouse is as much an organism as an elephant.

Last edited by louis (2012-06-02 18:15:36)

clark · 2012-06-01 18:54:30

http://www.nydailynews.com/news/mission … -1.1088536

Ha! Even the truly insane only plan 20 by 2030.

louis · 2012-06-01 19:13:06

clark wrote:

http://www.nydailynews.com/news/mission … -1.1088536
Ha! Even the truly insane only plan 20 by 2030.

You really take those proposals seriously? That's sad.

Tinned food? Isolated in their pods? Not allowed to speak to friends and family for a year before they go?

Complete and utter tosh.

However, nice graphics.

Louis: Good things happen all the time, and quickly too. You will be surprised how quickly we colonise Mars.

Rune · 2012-06-03 04:56:46

louis wrote:

No, I don't accept the 25 launch windows limitation. What exactly stops us transiting at sub-optimal times? As far as I can see, once you have your transit craft in place, it's really a matter of fuel.

Mainly, physics. The mass ratio of a rocket designed for Hohmann transits is completely incapable of achieving the much higher delta-v's of anytime travel. Sure, you can stage things and any velocity is achievable in theory. But there are limits to what is reasonable, or economical. A reusable chemical stage would launch once every two years, and would need refueling at both ends of the trip, period. No two ways around that, the window may be a bit wider or a bit narrower, but it will be a window, and it will happen every two years or so. If you want magic, invoke fusion like everybody else does.

louis wrote:

[EDIT: Schoolboy error on that calculation. Of course the key issue is how long people stay on Mars. I doubt there will be many lifetime stayers in 2070, so most people will be coming back to Earth. If the average stay by then is 5 years, you probably need something more like 200 craft - a significant increase over my previous estimate. Makes me think we will need to invest in creating superliners to ferry people between Earth and Mars, carrying more like 100 people than 10. ]

A plane carries hundreds of people. So do trains, or ocean liners, or the old wooden sailing ships. So hardly a superliner, just a decent-sized transport for a mature transportation system. I assume things like that (and bigger) will be flying by this time. Probably built in orbit in the first place, from materials not brought from Earth. But I would bet the oldest of them is no more than a couple of years into service. We are in the biplane era at most in manned spaceflight, if that much. Maybe in the glider era that preceded it.

louis wrote:

You're talking as though the only way to produce something is with a huge mass production factory. You're also talking as though Mars will be a high consumption society. I don't think it will in terms of private consumption. For many decades it will be a fairly frugal sort of society - in the sense that people won't be buying huge amounts of clothes, paper, carpets, curtains, furniture and so on - the sorts of things that consume so many resources on Earth. The production will go on the essentials of life: habitat construction, energy production, plumbing, wiring, lighting, agriculture, transport.

Contrary to what you think, Mars is going to be a VERY high consumption society, if you measure that consumption by the mass of the materials needing to be manufactured. Why? Well, because, just to name a few things, here in Earth you don't have to manufacture air, soil, or light. I don't care how much frugal the martians are on their needs, here on earth the square meters you need to live in came for free, the soil in which the food you eat is grown came for free, and the air you fill your lungs with is free. Or more correctly, a huge biosphere paid for it for you. In mars, every ton of air and soil has to be manufactured (of course with materials form Mars! no other way), every square meter of livable land has to be walled and protected, and most likely lit with additional lights. That is a huge added cost, and the machinery needed to produce all of that, and the new generations of machinery needed afterwards, is going to be huge. The size of the smallest possible >90% independent colony is likely to be much bigger also that you suppose (or I, for that matter).

louis wrote:

Louis: A mouse is as much an organism as an elephant.

And both need a full biosphere.

Rune. To make a pie, you must first create the universe, you know.

RobS · 2012-06-03 06:45:31

As long as the Earth is "behind" Mars in its orbit by, say, 30 to 120 degrees, a propulsive impulse will allow a ship to move out away from the sun and catch up to Mars. The size of the delta-v will vary. Once Earth passes Mars and is ahead of it, though, it is extremely difficult to get to Mars because any ship has the Earth's 100,000 kilometers per hour of forward motion around the sun, and you would need to cancel it out and fly around the sun retrograde; then when you encounter Mars, it's moving forward at 60,000 kilometers per hour, which requires a huge delta-v to land. You can't aerobrake off that velocity difference, either; the atmosphere is too thin.

There is a solution, but it also requires a lot of energy; rather than fly less than 180 degrees around the sun to encounter Mars, you fly more than 180 degrees around and catch up with it from the rear. But to do that, you have to fly closer to the sun. For example, a Hohmann trajectory to Mercury takes about 60 days, and when you are there a propulsive manuever in Mercury's gravity well will send you on a Hohmann trajectory to Mars, which takes 200+ days (I don't remember the exact times; you can look them up). You can do the same thing with Venus, but Venus and the Earth align fairly rarely compared to the Earth and Mercury (which align for a direct flight once every 100 days). With a powerful enough engine, you don't need an inner planet at all; you fly on an orbit that takes you closer to the sun, fire your engine at perihelion, and head back out to Mars, or you leave Earth on an elliptical orbit that goes close to the sun, then flies farther out and crosses Mars's orbit when Mars happens to be there. These inner planet encounters have been called "fry-bys" because your ship has to deal with a lot of heat and solar radiation. But if they are large and their technology is advanced, that's solvable.

I've written a massive 18-volume novel about the settlement of Mars--one volume for every 26 months--and in volume 16 (about 35 years after initial settlement of Mars) the Earth-Mercury-Mars trajectory is first initiated. At that point, Mercury has a small (50-75 person) station at the north pole next to an ice-filled crater and Mars flies "caravels" (flying saucer shaped vehicles that spin for artificial gravity inside, have a heat shield on their large, round bottoms, and can accommodate 150 people for six to 10 month trips) to bring migrants to the Red Planet. As a caravel approaches Mercury, a capsule containing up to twelve passengers heading for the innermost planet detaches and heads for "Portal" station, which is located in the penumbra of Mercury's L2 point. It uses a solar thermal engine to execute a 9 km/second delta-v to dock to Portal station, where a shuttle takes the passengers to the surface of Mercury. Meanwhile, another capsule with passengers heading from Mercury to Mars uses a solar thermal engine to head from Portal to the caravel, where it docks and deposits its passengers several days after Mercury flyby. This system gets passengers to the Mercury station more cheaply than a direct flight, because the caravel's costs are spread out among 150 passengers; it is also safer and more comfortable. The system also brings passengers to Mars roughly 9 months after the main flood of migrants had arrived, right after opposition, so it spreads out the demand on Mars's shuttles (which have to rendezvous with interplanetary vehicles in Mars orbit to land passengers and cargo). The system also ties Mercury and Mars together; the worlds have similar gravity and their scientists are doing similar geological research, so exchanges between them are valuable.

RobS · 2012-06-03 07:25:24

Unfortunately, there are so many unknowns about Mars and about the course of 50 years of settlement, it is hard to predict what the place could be like. My 18-volume novel carried Mars forward about 40 years. It assumed several things:

1. The initial price of launch to low Earth orbit was $2000/kg ($1000/lb) using Falcons and that reusable vehicles brought the price down to about a quarter or a fifth of that over 40 years.

2. The launch cost from low Earth orbit to Mars was initially 3 or 4 times as much as the cost to LEO and that it declined to a mere doubling after 40 years. So the cost of going from the surface of Earth to the surface of Mars drops from $7,000/kg to about $500/kg. You need to have some sense of this. This decline was accomplished through use of solar thermal rockets (very cheap) for trans-Mars injection of cargo, and them later solar sailers (even cheaper). Humans go to Mars on 6-month trajectories at first, and once fuel gets cheaper, 3-month trajectories. Toward the tail end of the novel, gas core nuclear becomes available and allows the interplanetary vehicles to complete 2 round trips every 26 months, rather than 1. Until then they usually use chemical propulsion; sometimes they use solid-core nuclear engines, but they are so expensive they aren't worth it.

3. The intial transport vehicle is a capsule with an inflatable hab able to transport 4. Larger habs allow 7 to use the capsule. Then a larger capsule is developed allowing 12 passengers plus an inflatable. Once you are flying a dozen or so of these capsules every opposition, you switch to the caravel, which is an inflatable with a heat shield on the ventral side and a small engine and fuel tanks on the dorsal side. It holds 125-150. When you are flying a half dozen of them, you switch to galleons, which have a similar design to the caravel but hold 450. The galleon II will hold a thousand passengers and is 65 or so meters in diameter and about 15 meters high. Shuttles flying between the Martian surface and orbit are modifications of the second stages of the shuttles flying from the Earth' surface to low Earth orbit, so their technology advances in tandem.

4. Phobos and Deimos are extremely important. Initially, they are the source for methane and oxygen fuel for trans-Earth injection and are visited twice every 26-month period for maintenance purposes (once when astronauts arrive from Earth and once when they depart). Early on, their water, methane, and oxygen are exported to Earth orbit to supply the fuel for trans-Mars injection. Once solar sailing technology comes on line, they are the cheapest source for everything off Earth, it just takes 1-2 years for the items to arrive! Caravels and galleons are placed permanently on Phobos to provide rotating, gravitied housing. Inflatable greenhouses stretch across the moon's surface to export food to the moon, Mercury, Venus and tourist hotels in low Earth orbit. Plastic made from Phobosian chondrite is used to manufacture zillions of export items. A large dry dock on Phobos is the place caravels and galleons are inflated, the different pieces imported from Earth are installed, and the shake-down cruises are between the moons.

5. Mars exports anything it can make a profit on. I am assuming they find some pretty rich gold deposits, and an ataxite or chondrite-enstatite body is found that is enriched in PGMs. Deuterium is enriched in Martian water. I assume that environmental protection hysteria makes it almost impossible to launch reactors, uranium, and plutonium into low Earth orbit, so Mars becomes the main source for radioactives. Because of the high cost of testing gas-core nuclear engines on the Earth's surface, both the US and China set up test reservations on Deimos, where the radiactive exhaust is harmlessly exhausted into interplanetary space.

6. Mars propaganda, from a very early point stresses that Mars is a very family friendly, safe place to live; no drug trafficing, no crime, a village that cares for everyone (and a great singles scene, though they don't advetise that). The aim is to encourage immigration, to inspire college students to aspire to emigrate to Mars, and they manage to retain 70-80% of the arrivals. You want some people to go back; they will then go to Mercury, the moon, become NASA administrators, etc., and their Mars experience will be useful for Mars's further expansion.

7. Mars is multicultural and very diverse. Early on, a Mars Commission is set up by the various space programs to settle and explore the place. As the flight price comes down, every country wants to have a citizen or two on Mars; it's one of those prestige items a country wants. As Mars gets bigger and more autonomous, it encourage competition. The Americans promise to send 1,000 over the next 10 years? Maybe China should send 1,200, then. That sort of thing.

8. Livability is an emphasis early on. After 10 years, most housing moves into inflatable "open ground" domes. The housing has large water tanks or agricultural terraces on their roofs for radiation protection. Pile drivers drive steel anchors deep into the ground to hold down the domes and thousands of tonnes of Martian water are added to the ground to form an "ice table" several meters down, to freeze the pore space shut and make the domes airtight. Wells monitor the water levels, inject warmed water into the ground when the dome temperature gets too high, pulls heat out of the ground water layer above the ice in the dust storm season, and desalinates the ground water as it causes chemical weathering of the regolith.

In my scenario, Mars reaches about 7,000 people in 40 years. Fortunately, whenever the Earth undergoes a recession and governments cut their subsidies, the price of gold goes up, so Martian income stays roughly the same. Population grows by about 30% every 26-year period and starts with 6. As the population grows, they gradually acquire more autonomy. The Commissioner in charge of the entire operation lives on Mars by about year 15 or 20, and the Commission gets abolished in favor of an independent "Mars Commonwealth" about year 35. Because Mars has many of the experts in space craft operation and design, it becomes the center for exploration of the outer solar system and a major economic partner for the moon, the asteroid belt, Venus orbit, and Mercury.

Last edited by RobS (2012-06-03 07:35:56)

SpaceNut · 2012-06-03 08:50:45

louis wrote:

What exactly stops us transiting at sub-optimal times? As far as I can see, once you have your transit craft in place, it's really a matter of fuel.

Rune wrote:

Mainly, physics. The mass ratio of a rocket designed for Hohmann transits is completely incapable of achieving the much higher delta-v's of anytime travel.

http://www.brighthub.com/science/space/ … 37154.aspx

Traveling to other planets is just like rendezvousing with another spacecraft in a different orbit, because that is exactly what you are doing. The interplanetary spacecraft is moving from Earth’s orbit to, say, Mars’ orbit, to rendezvous with the red planet. In traveling to Mars, the spacecraft is moving to a higher orbit. Remember from Orbital Mechanics part 1, to raise the apogee of an orbit, we fire the engines at perigee. On a Mars mission, Earth orbit is the perigee—but since we are leaving the home planet and moving into solar space, it is now called perihelion. Mars’ orbit is aphelion. A Hohmann Transfer Orbit trajectory does the job nicely, with the engines fired in the direction of Earth’s movement in it’s’ orbit.

Example:
=spirit-061203-browse.jpg.jpeg?size=webview

this is when spirit a rover will leave to Mars and its trajectory

As you can see from the image that is why we have only a 2 month launch wind as the fuel to get to mars greatly increases....

Now to answer the other part of the question for a slower transit: this is then about consumables, the life support system and effects of 0 g on the crew, longer exposue to radiation, ect... all of which increases the size of the ship....

Now onto the list of louis of which I agree that these are the major players in growth of a colony and are the main subject to ramping up of population with each transport of new members.. but if all that proceeding crews to mars each time comeback then there is no population growth...
Rune is also correct in the assertion of a much larger mass of machines to make life possible as it was noted here on earth that water, air, land, and power to an extent are free with minimal machines for the food we need.

GW Johnson · 2012-06-03 11:06:02

I surely am glad to see that porn spammer gone. My sincere thanks to whoever did that.

Here's something to think about when looking at a 50-year interval into the future: we're going to have way-better traveling machines 5 decades from now. 50 years ago, the original Atlas was severely challenged to loft a 4000 lb Mercury capsule to LEO. Now, its descendant Atlas-V-HLV can fling 29 metric tons to 23 deg LEO out of Canaveral.

We will not be limited forever to minimum-energy transfers, although they do now (and always will) make economic sense with unmanned stuff. For manned stuff, there'll be much hotter propulsion available, for the fast trips that are nearly straight-line shots to Mars. We've been yakking about NERVA, gas core NTR, pulse propulsion, and a host of others. Some are electric, some even solar.

I dunno what we'll really have 5 decades from now, but it'll make high-pressure LH2-LOX shuttle technology look like a quaint rotary engine-propeller combination on a WW1 biplane, as compared to the air turboramjets of the SR-71 ca. 1960. About 5 decades separates those two, also.

Far sooner than 50 years from now, you will not be limited to "best launch windows" to Mars that are about 2 years apart.

That is, if somebody will actually get to work on it, instead of retreading old shuttle stuff. Damn Congress anyway.

There has to be a way to "up" the engine thrust/weight on the electric stuff above 10^-4. There's a few guys working this, but it's not big time stuff. VASIMR is one, but they don't have a (T/W)engine solution, either. They have the Isp at around 6000 sec, they just don't have any significant vehicle acceleration capability. Until they do, it's not a fast-trip system.

There has to be a way to quickly and safely revive the NERVA/Dumbo-type nuclear thermal stuff. It will involve telling the politicos to either get lost or else get on board and tell their constituents the real truth about this stuff. Same for pulse propulsion (for which the really serious side effect is not radiation, it's EMP, something not yet understood in 1959, but we got an inkling of, in 1962).

Microgravity illness is fought with one of 2 things based on current physics: (1) fast flight times, or (2) spin the ship. We pretty much know the spin rate limit for "typical civilians": under 4 rpm. We don't know what partial gee is sufficiently therapeutic, so until we do, use 1 gee. Simple enough. At 4 rpm, that's a 56 m spin radius.

Radiation is fought with shielding. Use the water and wastwewater tanks you already know you gotta have anyway. Smart designers would make the shelter the flight deck. The enemy is not so much cosmic rays as it is solar storms. About 20 cm thickness of water is enough, and not so much as to cause secondary shower effects with the cosmic rays.

It doesn't have to be Battlestar Galactica: imagine a long slender ship assembled from docked modules about 300-500 tons in mass and maybe 150-300 m long. Put the habitat at one end, engines at the other. Now spin it end over end whenever in coast, at pretty close to 1-2 rpm. That ought to work, and be both dynamically stable and very easy to do. That's smaller than the ISS, and we built that (at $27,000/lb delivered; now it's down to $2500/lb, and it's soon headed for $1000/lb).

50 years from now, folks will think an assembly like that is tiny. In 10 years, it will look "just about right" for going to Mars, Venus, and the NEO's. In about 25 years, and with hot-enough propulsion retrofitted to the same basic hardware, it'll look pretty good for visits to the main asteroid belt.

Leaving Earth orbit does not mean we go back to the Apollo model of [one launch-one-trip, one trip-one landing, “flag-and-footprints” plus some towsacks of surface rocks]. We should instead take advantage of the orbital assembly we have learned over the last decade or so. And start thinking like real explorers. It's not a race this time.

GW

Last edited by GW Johnson (2012-06-03 11:09:58)

louis · 2012-06-03 11:48:06

Rune wrote:

louis wrote:
No, I don't accept the 25 launch windows limitation. What exactly stops us transiting at sub-optimal times? As far as I can see, once you have your transit craft in place, it's really a matter of fuel.
Mainly, physics. The mass ratio of a rocket designed for Hohmann transits is completely incapable of achieving the much higher delta-v's of anytime travel. Sure, you can stage things and any velocity is achievable in theory. But there are limits to what is reasonable, or economical. A reusable chemical stage would launch once every two years, and would need refueling at both ends of the trip, period. No two ways around that, the window may be a bit wider or a bit narrower, but it will be a window, and it will happen every two years or so. If you want magic, invoke fusion like everybody else does.

NASA seem to agree with me. From their site:

"When travelling among the planets, it's a good idea to minimize the propellant mass needed by your spacecraft and its launch vehicle. That way, such a flight is possible with current launch capabilities, and costs will not be prohibitive. The amount of propellant needed depends largely on what route you choose. Trajectories that by their nature need a minimum of propellant are therefore of great interest. "

I am not getting the message from that that a Direct Shot is impossible. I am getting the sense that you would have to put up so much fuel/propellant that it is highly desirable to avoid them and stick with Hohmann transfers. However, against that, I think you have to accept that we will be in a different era once we are established on Mars. Musk and Space X have already dramatically reduced the cost of launches and Musk hopes to get them down to less than a $1000 per Kg. If you then factor in that we can get rocket fuel to orbit much more easily from Mars, I think we can consider moving outside the launch windows, at least for passenger craft (perhaps cargo would stay within the Hohmann launch windows).

Unfortunately I haven't been able to find any figures for how much more propellant/fuel you need per Kg of load to operate outside the launch windows.

Rune wrote:

louis wrote:
[EDIT: Schoolboy error on that calculation. Of course the key issue is how long people stay on Mars. I doubt there will be many lifetime stayers in 2070, so most people will be coming back to Earth. If the average stay by then is 5 years, you probably need something more like 200 craft - a significant increase over my previous estimate. Makes me think we will need to invest in creating superliners to ferry people between Earth and Mars, carrying more like 100 people than 10. ]
A plane carries hundreds of people. So do trains, or ocean liners, or the old wooden sailing ships. So hardly a superliner, just a decent-sized transport for a mature transportation system. I assume things like that (and bigger) will be flying by this time. Probably built in orbit in the first place, from materials not brought from Earth. But I would bet the oldest of them is no more than a couple of years into service. We are in the biplane era at most in manned spaceflight, if that much. Maybe in the glider era that preceded it.

Well in terms of space travel I think it would be a superliner. All things are relative. How about ten transits as a lifetime for such a vehicle?

Rune wrote:

louis wrote:
You're talking as though the only way to produce something is with a huge mass production factory. You're also talking as though Mars will be a high consumption society. I don't think it will in terms of private consumption. For many decades it will be a fairly frugal sort of society - in the sense that people won't be buying huge amounts of clothes, paper, carpets, curtains, furniture and so on - the sorts of things that consume so many resources on Earth. The production will go on the essentials of life: habitat construction, energy production, plumbing, wiring, lighting, agriculture, transport.
Contrary to what you think, Mars is going to be a VERY high consumption society, if you measure that consumption by the mass of the materials needing to be manufactured. Why? Well, because, just to name a few things, here in Earth you don't have to manufacture air, soil, or light. I don't care how much frugal the martians are on their needs, here on earth the square meters you need to live in came for free, the soil in which the food you eat is grown came for free, and the air you fill your lungs with is free. Or more correctly, a huge biosphere paid for it for you. In mars, every ton of air and soil has to be manufactured (of course with materials form Mars! no other way), every square meter of livable land has to be walled and protected, and most likely lit with additional lights. That is a huge added cost, and the machinery needed to produce all of that, and the new generations of machinery needed afterwards, is going to be huge. The size of the smallest possible >90% independent colony is likely to be much bigger also that you suppose (or I, for that matter).

I was careful to say PRIVATE consumption. I think if you look around your home and start subtracting the many things you won't find in the Mars settlement - home furnishings, "throwaway" clothes, cars, large cookers, lamp standards, books, newspapers etc that takes out a huge amount of per capita material. In the first decades we won't have needs of roads, and all the huge amount of road signage. We won't have aeroplanes. Apart from the demands of space medicine, the Mars inhabitants should relatively young and in A1 health. There will be a huge resource saving there. Similarly, to begin with, Mars won't be carrying the burden of raising or educating children and young people. There will be no crime, no need for police or courts, no people dependent on welfare. No armies or security services. Put all that together and you have huge resource savings.

I agree though, that in terms of resource use, Mars inhabitant may still use more than Earth inhabitants. It is certainly true their energy use will be far greater than that of Earth inhabitants.

We have our living spaces on Earth as well. The key difference (a resource-heavy one) is pressurisation. I think to a certain extent there will be some "gain" for Mars in that the living space allowance will be less generous than on Earth. If we also build with my favoured method of trench and cover the amount of construction materials required will be far less.

I think the biggest resource call will be agriculture, because of the lack of organic matter on Mars, and the need to produce something like half a tonne of food per annum per person. Of course once you have your soil, with careful husbanding, and recycling of organic matter it needs only a little "topping up".

I guess rocket fuel will be another huge call and rocket manufacture also when that becomes possible.

Impaler · 2012-06-03 12:05:25

Just as an aside if Solar Electric propulsion or any low thrust high ISP system is used on slow trajectories of 1-2 years the Delta V 'window' issues is greatly diminished because your craft is going into Solar orbit initially matching that of the Earth and transits to an orbit matching Mars eliminating most of the repetitive velocity issues. Effectively your Delta V cost is always well above the Hollman minimum but its far more consistent varying only +-20% for any Earth-Mars position. The transit times mean this is really only a Cargo option of course but it's very nice to be able to send Cargo to any hypothetical Mars base continually rather then waiting through 26 month intervals. We manage to maintain Antarctic research stations with a cargo resupply window of 3 out of every 12 months but supplying a base under windows of 1 of every 26 months would be a MUCH harder thing, you need to stockpile a lot more and the delivery process needs to be a lot more reliable.

RobS: Your list of preconditions is good in the sense that I agree that all that needs to happen for any kind of settlement to occur. I'm skeptical of the rate though, is your 40 year time-frame starting from today or at the fist landing (which I'd put beyond 2035 minimum). If your timeline starts their and all the preconditions are filled then say it's reasonable to have Antarctic Station level of activity on Mars in the 2200 time frame, even that station would be have a cost comparable to the ISS program, several Billion dollars a year, a similar amount of money would likely be spent on similar stations on the Moon and in follow-on ISS stations.

louis · 2012-06-03 17:53:24

RobS wrote:

Unfortunately, there are so many unknowns about Mars and about the course of 50 years of settlement, it is hard to predict what the place could be like. My 18-volume novel carried Mars forward about 40 years. It assumed several things:
1. The initial price of launch to low Earth orbit was $2000/kg ($1000/lb) using Falcons and that reusable vehicles brought the price down to about a quarter or a fifth of that over 40 years.

Well we are about there now aren't we?

RobS wrote:

2. The launch cost from low Earth orbit to Mars was initially 3 or 4 times as much as the cost to LEO and that it declined to a mere doubling after 40 years. So the cost of going from the surface of Earth to the surface of Mars drops from $7,000/kg to about $500/kg. You need to have some sense of this. This decline was accomplished through use of solar thermal rockets (very cheap) for trans-Mars injection of cargo, and them later solar sailers (even cheaper). Humans go to Mars on 6-month trajectories at first, and once fuel gets cheaper, 3-month trajectories. Toward the tail end of the novel, gas core nuclear becomes available and allows the interplanetary vehicles to complete 2 round trips every 26 months, rather than 1. Until then they usually use chemical propulsion; sometimes they use solid-core nuclear engines, but they are so expensive they aren't worth it.

I certainly use a factor x4 for calculating cost to Mars. I think it feels about right, even if it is difficult to quantify.

RobS wrote:

3. The intial transport vehicle is a capsule with an inflatable hab able to transport 4. Larger habs allow 7 to use the capsule. Then a larger capsule is developed allowing 12 passengers plus an inflatable. Once you are flying a dozen or so of these capsules every opposition, you switch to the caravel, which is an inflatable with a heat shield on the ventral side and a small engine and fuel tanks on the dorsal side. It holds 125-150. When you are flying a half dozen of them, you switch to galleons, which have a similar design to the caravel but hold 450. The galleon II will hold a thousand passengers and is 65 or so meters in diameter and about 15 meters high. Shuttles flying between the Martian surface and orbit are modifications of the second stages of the shuttles flying from the Earth' surface to low Earth orbit, so their technology advances in tandem.

Sounds interesting.

RobS wrote:

4. Phobos and Deimos are extremely important. Initially, they are the source for methane and oxygen fuel for trans-Earth injection and are visited twice every 26-month period for maintenance purposes (once when astronauts arrive from Earth and once when they depart). Early on, their water, methane, and oxygen are exported to Earth orbit to supply the fuel for trans-Mars injection. Once solar sailing technology comes on line, they are the cheapest source for everything off Earth, it just takes 1-2 years for the items to arrive! Caravels and galleons are placed permanently on Phobos to provide rotating, gravitied housing. Inflatable greenhouses stretch across the moon's surface to export food to the moon, Mercury, Venus and tourist hotels in low Earth orbit. Plastic made from Phobosian chondrite is used to manufacture zillions of export items. A large dry dock on Phobos is the place caravels and galleons are inflated, the different pieces imported from Earth are installed, and the shake-down cruises are between the moons.

I am not convinced about the Phobos and Deimos benefit - you've got to operate on them and you have to put in a full support structure for that. That's costly.

RobS wrote:

5. Mars exports anything it can make a profit on. I am assuming they find some pretty rich gold deposits, and an ataxite or chondrite-enstatite body is found that is enriched in PGMs. Deuterium is enriched in Martian water. I assume that environmental protection hysteria makes it almost impossible to launch reactors, uranium, and plutonium into low Earth orbit, so Mars becomes the main source for radioactives. Because of the high cost of testing gas-core nuclear engines on the Earth's surface, both the US and China set up test reservations on Deimos, where the radiactive exhaust is harmlessly exhausted into interplanetary space.

Good point about the radioactives. Mars is good for that.

I don't think we should consider only mineral wealth. There are many other ways of developing Mars. For one thing, I wouldn't be surprised if creative and design agencies located there. They might find the location brings them extra business. They will be able to meeting with earth based clients through virtual meeting technology.

RobS wrote:

6. Mars propaganda, from a very early point stresses that Mars is a very family friendly, safe place to live; no drug trafficing, no crime, a village that cares for everyone (and a great singles scene, though they don't advetise that). The aim is to encourage immigration, to inspire college students to aspire to emigrate to Mars, and they manage to retain 70-80% of the arrivals. You want some people to go back; they will then go to Mercury, the moon, become NASA administrators, etc., and their Mars experience will be useful for Mars's further expansion.

I think for the first 50 years I don't think there will necessarily be a strong pro-immigration policy. There are going to be a lot of conflicting pressures I think.

RobS wrote:

7. Mars is multicultural and very diverse. Early on, a Mars Commission is set up by the various space programs to settle and explore the place. As the flight price comes down, every country wants to have a citizen or two on Mars; it's one of those prestige items a country wants. As Mars gets bigger and more autonomous, it encourage competition. The Americans promise to send 1,000 over the next 10 years? Maybe China should send 1,200, then. That sort of thing.

I think that sort of national competition is quite likely. The community will of course be very multi-racial from early on because America is and I think Space X, will be drawing on the US community to begin with. It will I believe resemble a cross between an American university campus, a military base, and an Antarctic base.

I think there will be religious rivalry as well. Mormons, Muslims and Mennonites will definitely want to get in on the act! Muslims with Saudi backing will probably have the funding available to make it a reality as well.

RobS wrote:

8. Livability is an emphasis early on. After 10 years, most housing moves into inflatable "open ground" domes. The housing has large water tanks or agricultural terraces on their roofs for radiation protection. Pile drivers drive steel anchors deep into the ground to hold down the domes and thousands of tonnes of Martian water are added to the ground to form an "ice table" several meters down, to freeze the pore space shut and make the domes airtight. Wells monitor the water levels, inject warmed water into the ground when the dome temperature gets too high, pulls heat out of the ground water layer above the ice in the dust storm season, and desalinates the ground water as it causes chemical weathering of the regolith.

Interesting ideas.

RobS wrote:

In my scenario, Mars reaches about 7,000 people in 40 years. Fortunately, whenever the Earth undergoes a recession and governments cut their subsidies, the price of gold goes up, so Martian income stays roughly the same. Population grows by about 30% every 26-year period and starts with 6. As the population grows, they gradually acquire more autonomy. The Commissioner in charge of the entire operation lives on Mars by about year 15 or 20, and the Commission gets abolished in favor of an independent "Mars Commonwealth" about year 35. Because Mars has many of the experts in space craft operation and design, it becomes the center for exploration of the outer solar system and a major economic partner for the moon, the asteroid belt, Venus orbit, and Mercury.

I think Musk is likely to favour early self-government so I wouldn't deny that could come earlier than we suspect. I have noted elsewhere that self-government is not banned by the Outer Space Treaty.

Perhaps we will see something a bit like the self-government enjoyed by a university.

RobS · 2012-06-03 21:23:17

Of course, what I wrote was a novel, and when you are writing a novel you need to speed things up somewhat for dramatic purposes. I doubt Mars could grow as fast as I make it; or perhaps it would be more precise to say that I have traced an optimal speed and reality will be slower.

I used some of the other ideas you mention, too. Once private groups can immigrate to Mars, the Mormons establish a strong presence (they develop various businesses, including a department store that eventually becomes a part of Walmart), an imaginary evangelical church in Nigeria sends lots of folks (they get into construction early and build the first church), a Zen monastery (they do agriculture and set up a big statue of the "Mars-witnessing Buddha," and are always telling people to slow down and relax more) and a new age religious movement that seeks to green father Mars with fertility from mother Earth (they get into large domes with terrestrial ecologies and sell lots of agricultural products, and have some strange rituals). The last group creates their own village in the wilderness. The first Mormon temple, Baha'i temple, and Catholic cathedral all get built about the same time, about 30 years on; a round mosque (with a mehrab or prayer niche that can be moved, depending on which wall is closest to Earth at the time) is built a few years later. The Wahhabi women can appear in public, fully covered of course, if they are accompanied by robotic chaperones. There is also an active philosophy club and various clubs pushing socialism, capitalism, and other ideologies, and lots of agnostics and atheists of course. Mars also has a small pool of people able to make movies, thanks to a James Cameron type who travels to Mars twice and stays for two years each time to make movies there. A university is founded very early, though it doesn't amount to much for a few years (neither did Harvard, for 6 or so years). A hospital is also founded early on. The big pork-barrel project Mars gets is "Bio-archive," a project to set up domes on Mars representing fairly complete ecologies (by year 38, Serengeti dome even has a few lions, which soon discover they can jump quite high and pull monkeys from the lower branches of trees). Bio-archive is a ridiculous waste of money (like many NASA projects?) but it is helpful anyway. The novel follows quite a few different characters, including a pot-smoking navy officer in charge of the United States' plutonium manufacturing effort and a very ambitious Indian civil engineer). I used to have it on the web and will probably put it back up some time; currently I am rereading and editing.

Last edited by RobS (2012-06-03 21:26:10)

RobS · 2012-06-03 21:51:47

Impaler: I started with the Earth departure in July 2035 and Mars landing in February 2036. The novel ends in November 2073. The dates are rather arbitrary; I had started setting everything in 2020, but decided that was too soon, and I had to shift everything 15 or 17 years because I didn't want to recalculate all the opposition dates (which recur on a 15 to 17 year cycle). As it was, the shift caused problems when characters commented about US presidential elections, which would have occurred 16 years later rather than 15, but I resolved that by having them talking about primaries instead and assumed that primaries had gotten pushed so early that they occurred the fall before the election. This actually made for a useful satire about the ridiculous nature of American politics. With the Falcon and Dragon, a Mars landing could indeed happen in 2022 or 2024, but I think the early 2030s are more likely.

If the price of getting people to Mars drops to about 1/100th the cost of getting stuff to the International Space Station via the Space Shuttle (which is what I assume, bu the 2060s and 2070s), you can see how much bigger Mars can be with the same budget as ISS. By 2073 it's exporting several hundred tonnes of gold and several hundred tonnes of platinum-group metals every 26 months. Gold currently is close to $2,000 per ounce, which is $32,000 per pound and $64 million per tonne, and with continued economic growth worldwide, the price can only go up, so 100 tonnes per year can bring in 6.4 billion dollars. Of course, we have no idea whether Mars has gold deposits, how rich they are, and where they are. If you assume as much gold on Mars as on the dry land on Earth (which is comparable in area, though the geology is different) and you start exploiting only the very richest deposits (which is what you would do), and if a gold mining settler can be gotten to Mars and equipped there for even $64 million (and by the end I have the price down to about $3 million in 2000 dollars), you can make money exporting gold. Terrestrial operations are currently recovering an ounce or two per ton of rock processed; they are going after very thin deposits because the rich ones are used up.

louis · 2012-06-04 01:20:21

RobS wrote:

Impaler: I started with the Earth departure in July 2035 and Mars landing in February 2036. The novel ends in November 2073. The dates are rather arbitrary; I had started setting everything in 2020, but decided that was too soon, and I had to shift everything 15 or 17 years because I didn't want to recalculate all the opposition dates (which recur on a 15 to 17 year cycle). As it was, the shift caused problems when characters commented about US presidential elections, which would have occurred 16 years later rather than 15, but I resolved that by having them talking about primaries instead and assumed that primaries had gotten pushed so early that they occurred the fall before the election. This actually made for a useful satire about the ridiculous nature of American politics. With the Falcon and Dragon, a Mars landing could indeed happen in 2022 or 2024, but I think the early 2030s are more likely.
If the price of getting people to Mars drops to about 1/100th the cost of getting stuff to the International Space Station via the Space Shuttle (which is what I assume, bu the 2060s and 2070s), you can see how much bigger Mars can be with the same budget as ISS. By 2073 it's exporting several hundred tonnes of gold and several hundred tonnes of platinum-group metals every 26 months. Gold currently is close to $2,000 per ounce, which is $32,000 per pound and $64 million per tonne, and with continued economic growth worldwide, the price can only go up, so 100 tonnes per year can bring in 6.4 billion dollars. Of course, we have no idea whether Mars has gold deposits, how rich they are, and where they are. If you assume as much gold on Mars as on the dry land on Earth (which is comparable in area, though the geology is different) and you start exploiting only the very richest deposits (which is what you would do), and if a gold mining settler can be gotten to Mars and equipped there for even $64 million (and by the end I have the price down to about $3 million in 2000 dollars), you can make money exporting gold. Terrestrial operations are currently recovering an ounce or two per ton of rock processed; they are going after very thin deposits because the rich ones are used up.

Yes, I always make the same point when discussing gold mining. People sometimes assume you are talking about going several kms under the surface like they do in South Africa, whereas we are really talking about using a power drill to get the stuff out on the surface from some exposed deposits.

Of course there is the issue of processing. The ore can probably be purified substantially with not too many resources on Mars. Of course, we don't have to worry about pollution on Mars...well, within reason I mean.

Impaler · 2012-06-04 03:05:20

Oh Brother... GOLD mining as an economic justification? Do you have any idea how ridiculous that is, even if Mars had deposits far richer then any on Earth (exceedingly doubtful) the mass of equipment needed to establish and conduct modern mining operations is just staggering. A hundred tons of gold is more then the largest mine on Earth produces from Open Pits that are miles across and which process in excess of a hundred thousand tons of ore a day. Not to mention the price of gold is horribly unstable in the long term, a few decades ago it was worth a fraction of its present value and a few decades prior to that it was worth even more then today (inflation adjusted), if the demand for gold jewelry declines the price will collapse.

Are we trying to have a serious discussion here or are we engaging in 'soft' Sci-Fi fantasy unhinged from reality? I'm getting the sense that half this forum is trying to be serious and engage in at-least a minimum BOE calculations and sanity checking and the other half is engaging in the wildest fantasies. Am I out of line to expect a high caliber of engineering and logical rigor on the forum, I thought that was the point of the Mars Society?

Last edited by Impaler (2012-06-04 03:09:06)

Glandu · 2012-06-04 05:07:48

Louis : Gold mining is exactly the kind of operation that is extremely steel-consuming. Everything, in fact, will be steel-consuming, as everything will need tools, and most of the time tools are best made of steel.

We will need shitloads of steel. Period. It can't be replaced for many tasks, including the most basic ones for survival.

RobS · 2012-06-04 06:33:58

You certainly won't starting exporting anything like a hundred tonnes a year. You'd start the way all mines start: going after extremely high concentrations. So you'd start with only one or two localities special localities. They won't last long; pretty soon you'll be going after poorer concentrations and mining underground to go after them. But the initial rich concentrations, and some investment, will get you started, and the poorer concentrations will keep you going. That's the idea, anyway. There may be new technologies to use, too, such as "panning" for gold with liquid carbon dioxide.

Regarding the price of gold, apparently a very large fraction of it is consumed making jewelry for India, where the culture expects women to have gold jewelry. As the economy of India grows, that demand can only go up. Economic uncertainty generally pushes up the gold price, too.

clark · 2012-06-04 08:16:49

To Impaler: you are on a board discussing the feasibility of people living out their days in a glorified soda can, surrounded by vacuum, on an alien planet. To put it mildly, who died and decided that your brand of logic represented what was and was not sane?

If some of you actually spent the same amount of time and energy thinking of what living on mars really meant, as opposed to the clinical effort of calculating how to get there, you might realize how insane all of this really was.

GW Johnson · 2012-06-04 09:22:42

Well, right after the initial "tin can" base setup, it might not be quite so confining if the folks there had supple, lightweight mechanical counterpressure suits, instead of the clumsy gas balloons we have been using. Think vacuum-proofing "underwear", and ordinary outer clothing suited to the weather and the job. We've known how to do this since 1969. Only inappropriate compression requirements are holding it back today.

Then there's habitats. Big open spaces inside, and good panoramic views outside, tend to support mental health. Sounds like the "tin can" approach is the wrong one, long term. The old science fiction transparent pressure domes concept points the right way, it just has to be done with regard to meteroid repair and radiation protection. Clear walls, solid roof.

The real problem is open-"air" agriculture on Mars. 7 mbar total P, 0 mbar water vapor partial-P. Ain't gonna happen until Mars gets terraformed some. That means dry-land plants and animals and soil organisms will need the same sort of clear-wall/solid roof dome that the folks live in, just whopping larger to cover the acreage. I dunno how to do that, but I bet we do know in less than 50 years.

Meanwhile, it might be possible to do aquaculture farming in ponds under an ice-plus-regolith cover. Done right, the water plus ice supplies the external pressure on the organisms. No spacesuit needed, just a wetsuit and oxygen scuba rig. No pressure dome. But because there is no pressure dome, this concept is scalable to very large acreages very easily. Underneath cover like that, we're talking artificial lights for the photosynthesis, whose waste heat keeps the water liquid.

There's clearly things we could do to keep folks on Mars sane and healthy and living productive lives. But it won't (and can't) look like Earth until the planet is terraformed.

I agree, living inside a tin can is definitely not the way to do it. Even nuclear sub crews need lots of time ashore.

GW

Impaler · 2012-06-04 11:57:01

RobS: Indian culture could easily come to the realization they are over-paying for Gold and opt for different Jewelry styles, cultural practices are subject to change under market forces and they are changing no ware faster then in the rising Asian states. Meanwhile Political uncertainty that drives up Gold prices also makes financing of new Maned Space flight missions exceedingly unlikely so 'gold from space' is a self defeating idea, the stability necessary to make any space adventuring possible would deflate the gold price. The same logic can be applied to virtually any rare resource that might be obtained in space, if we haven't figured out how to recycle or substitute for those materials in coming decades were not going to be living in a world that can afford ambitious space programs.

clark: Actually I agree with you LIVING on Mars is insane, the serious people talk only about exploring Mars in what amounts to a Martian Apollo program.

GW: Nuclear Subs, ISS and every single long-duration isolation study show that tin-cans are perfectly adequate for a multiple years when you select tough individuals. A mars first landing expedition crew is going to be selected from people with nerves of steel and I have no doubt they will be able to cope with isolation and confinement if given space station levels of volume.

clark · 2012-06-04 12:29:42

Impaler, the mars society is predicated on colonizing mars, so your expectation of what should constitute appropriate behavior is misplaced.

If you believe in exploration only, and are rationale, impaler, then you know that human space exploration is a fools errand. Sending humans to explore only makes sense if you want to send people there permanently, otherwise you are better off with robots.

But I digress, living on mars, or space, is a life of loss.

RobS · 2012-06-04 14:39:39

GW Johnson: I don't think a roof is needed. Solar radiation is screened out enough by the atmosphere for plants, probably even during solar storms; they are a lot tougher than humans. Cosmic radiation won't kill plants in the quantity we're dealing with, either. As for micrometeoroids, as far as I know, anything smaller than a fist is stopped by the Martian atmosphere as well; Mars doesn't have tiny craters. As far as I know, open domes are not limited by either of those factors. They are rather daunting engineering challenges, though.

Counterpressure suits: I agree, something like that is needed.

Impaler: You may be right about the Indians and jewelry and the rest of the discussion about gold and PGMs. I don't know. But there are a lot of people with business plans to harvest PGMs from asteroids, so there are people who think that will work, and it may be easier to do it on the moon or Mars where there's gravity to make the separation processes work, than in zero gee. Otherwise, you're hauling back to earth about 5,000 to 10,000 tonnes of nickel/iron/cobalt for every tonne of PGMs, and that can't be more profitable than extracting the stuff on the moon or Mars. Dennis (?) Wingo has published an entire book about mining PGMs on the moon.

Clark: I am not sure what you are saying. The humans versus robots debate is quite old and I suspect even as robots get better, we'll find a value for humans to be involved, especially as the technology for transporting them and keeping them alive and comfortable gets better. But who knows; my crystal ball hasn't been very clear.

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