The W7-X Is One Step Closer to Creating Nuclear Fusion
I've heard of Max Planck and thought it was just a prank...well, maybe not. Seems his work has merit. Although it's just a teaser right now, they haven't actually created power quite yet.
Do you really think that Fusion is possible and is it really better than anything else that is being worked on.
I think power should be generated at each building or utility instead of all these wires all over the place.
What say you?
Do you really think that Fusion is possible and is it really better than anything else that is being worked on.
I think power should be generated at each building or utility instead of all these wires all over the place.
What say you?
Just like homopolar motors (the only true DC motor). They only have one problem, current collectors (brushes). I recall saying this to my old boss. He had worked at Ford in the 1960s. He said they has developed an efficient, continuously variable transmission using homopolar motor-generator sets. The only problem with these, vastly superior to hydraulic transmissions was current collectors. It is now 2016, and the problem is still, current collectors.
Laughing...
The money pit of magnetic confinement has topped $100B. By comparison, inertial confinement devices have shown impressive results with less than one percent of that amount of funding. I strongly suspect that either laser implosion or inertial electrostatic confinement devices will reach break even before the massive, incredibly expensive magnetic confinement machines.
Max Planck rates right up there along with Einstein as one of the great minds that introduced us to quantum physics. Fusion exists in nature. It is what powers stars. Therefore, like anything else in nature, since we know it exists, it is our obligation -- make that our duty, as a species, to replicate this unendingly great power source.
This understanding will take a while to sink in.
The Electric universe model explains some of this, as best I understand it.
Is this some kind of a test? Perhaps.
Controlled Fusion has been the "Holy Grail" of power science for decades. It will most likely be so for several more. I do recall that several promising areas were abandoned 15 to 20 years ago because of a lack of funding. If a reliable source of research funding in sufficient amounts is made available It just might not be decades away but a relatively res years away for the first fusion reactor.
Now me dino has no problem with fossil fuel, mind you, but a proven to be safe fusion fuel engine for trains, planes and automobiles--not to mention electric power generation--should send all those of econazi control freaks looking for something else to be pesky about.
But a massive power plant to drive an all-electric railway system? That's easy to imagine.
https://en.wikipedia.org/wiki/Dilithi...
Wikipedia says fictional dilithium crystals can only be found on certain planets (not of this earth?).
If those crystals are not of this earth, that begs a question about a William Shatner Star Trek movie in which the Enterprise goes back in time.
Movie ends with some World War III survivor dude breaking the light speed barrier with that attracting flying by Vulcans to make a close encounter of the third kind.
I do not recall what the light speed barrier breaker used for fuel. Maybe he found a dilithium crystal meteorite like how kryptonite is obtained to be used against Superman.
As Robin William's Popeye once said, "I have a sensk of humiligration."
Unfortunately barring some unexpected and massive breakthrough in surface-to-orbit technology that reduces the cost to a tiny fraction of what it is now, those powersats won't be coming from Earth. It sounds strange, but for the cost of getting a few powersats into orbit from Earth you could bootstrap a manufacturing facility on Mars that would then continue to produce and ship powerboats to Earth-GEO cheaper.
As an aside as to why it is so much cheaper from Mars:
The energy it takes to go from the bottom of a gravity well is dominant. Thus the energy cost, which drives 99% of the cost of the trip, is far greater from Earth than from Mars. Once you've hit orbit you are "halfway to anywhere in the solar system" as we say. Thus the energy cost is dramatically less from Mars' surface than Earth's surface.
Because this is fundamental, anything that provides that energy cheaper, such as more efficient rockets, does not change the equation. The only tech that would make a difference in the cost differential would be an "instant-teleport" mechanism which bypasses the effect of gravity.
However, in addition to the transportation costs you'd need to factor in the considerable regulatory costs of such a massive manufacturing industry. Unless you could get the factories built in a country that had lax regulations and strong protections against "nationalization" those costs would be lower off-planet. Surprisingly, much of the infrastructure needed for rocketry is shareable with power-sats and not that complicated either.
Now as to transmission safety aspect, the area it would transmit to is generally designed to be fairly broad (kinda has to be to account for beam divergence), and thus the relative poor is really low regarding say a bird flying into it. They would not be useful as a weapon either due to the beam dispersion but a simple failsafe is one of "connected" rx/tx links with GPS targeting boundaries. The former means it is tied to a unique receiver station that must be within the beam for it to transmit. Think of it like a lock and key. The second is a safeguard against someone somehow moving the receiver.
I suspect space based power systems are more likely to be used to power other space based infrastructure. Once the issue of affordable energy storage is resolved, and solar, wind, and geothermal technologies become less expensive, terrestrial power sources will be less demanding than trying to capture Earth's power from space.
But are you sure you need to locate your mine, smelter, and mills on Mars? The Moon might hold some of the needed materials. Failing that, meteoroids are made primarily of iron and nickel--key metals for raw materials.
It requires less energy to go to Mars than the moon - from Earth's surface. The critical difference is the lack of atmosphere. For mars it is just enough atmosphere to provide aerobraking - the act of letting the atmosphere slow you down. The moon, lacking any atmosphere for aerobraking, requires you bring enough fuel to counter the fuel expended to get there. All the delta-v you build up trying to get to the moon has to be countered by thrust provided by rockets you bring - and the fuel to do that. This is the recursive problem of rocketry - since you have to bring more fuel to slow down you need more mass meaning you need more fuel - you can see where this is going.
Now that isn't an infinite recursion but it is enough of one to make it a lot more expensive in terms of mass budget and hence energy requirements and thus cost. So every dollar spent on getting to the moon to build a moon base - and we are only talking about the act of getting there - is less productive and costlier than doing the same on Mars. The moon has other no-atmo problems which increase mass requirements such as shielding and far more drastic thermal variances to deal with, so from a cost perspective it doesn't work out. It only would if and only if there was some resource that could only be obtained from Luna. So far, we don't have anything fitting that bill.
To give you an idea of the numbers (from memory, so bear with me please), from LEO (Low Earth orbit) to the moon requires a delta-v of 6 kilometers per second - nearly a third of that is the landing. From that same orbit to Mars is 4.5 of which only .4 Km/s is for landing. That thin atmosphere makes an enormous contribution indeed!
The asteroid belt does indeed have an abundance of source materials. However, it has economic problems not unlike those of Luna. Indeed, any economically successful attempt at mining "the belt" will depend on Mars. Given that it is easier/cheaper to get to Earth's moon from the surface of Mars you might suspect it is true about the belt, say to Ceres. This is true. Now for this we really want to talk about the mass ratio - the ratio of propellant to cargo (including spacecraft) mass - because mining the belt is all about cargo.
For getting to Ceres, for example, from Earth you have a mass ratio of about 153. Higher numbers are worse. From Mars it is 11. So even to get the mining equipment there it is dramatically more expensive to ship from Earth. Next up are the atmosphere and gravity issues. Frankly, we don't know how to mine an asteroid. Our techniques and equipment all assumes gravity and atmosphere and rely on one or both of these to operate. Thus to mine asteroids means we need to develop that tech and knowledge. Even if we had the technology, a round trip mining mission for 1000 tonne dry cargo gives Mars a 50-fold advantage in propulsion costs alone.
Contrast that to Mars which has both atmo and gravity. Our techniques and technology directly apply to mining on Mars. From there we could cost-effectively send people and/or robots fro Mars to a nearby asteroid for developing that knowledge. Mars is close enough you could, depending on the asteroid, have reasonable latencies for tele-operation.
Every route to exploring, settling, or mining anywhere off-Earth in the solar system is routed through Mars unless you have unlimited funds and a radical anti-Mars stance. Mars is the way station to the stars for humanity. It is a bit like a halfway house for us. Just enough gravity and atmo to be familiar and useful, and located at just the right spot to build the rest of the solar system's infrastructure. It has relatively easy access to the belt, not to mention the entire planet and two nearby moons, from which it can build out even more infrastructure and economy.
Personally, given current technology, the way to go is to build up Mars, and then from that base (possibly w/raw unprocessed material from the belt) build a series of tether launchers to provide orbit-to-orbit infrastructure. Imagine a giant rotating tether where there is shook on one end and a large mass on the other.
For these, the transit craft is launched toward the hook, rendezvousing with it where it gets the delta-v boost needed to put it on a trajectory to the one that "catches" it at the destination (more at https://en.wikipedia.org/wiki/Momentu... ). These require far too much mass to be sent from Earth, and possibly from Mars. But they would reduce the cost of in-system transit enormously.
One last thing: We have the tech and materials to build a space elevator on Mars. We could possibly even build a "rotavator" - a tether that reaches down aspics up (or drops off) cargo from the surface of Mars, or the moon. But these all require significant raw mass. Thus, would be best built from Mars inward. Hell, if you haven't yet go check out that wikipedia link above. That is how, barring unforeseen massive leap in unknown technology, mankind will grow to the stars - and all from Mars.
In Quaid's famous words ... "Get yer ass to Mars" :D
Why is Phobos in the way? Because areostationary Martian orbit is going to be a lot higher than is geostationary Earth orbit. High enough to coincide with the orbit of Phobos.
And actually I don't propose to mine the asteroids. Meteoroids, yes, but not asteroids. You're going to find nothing there but water (with twice as much heavy water as you'll find on earth) and plain ordinary rock. Mars has the mineral wealth. The asteroids will come in handy when, as, and if we solve the contained fusion problem.
You can get down to Mars, I'm sure, with less delta-V (though the transit time is a lot longer). But how about lifting something up? On the Moon you can build an escape-speed induction catapult. On Mars, you need rockets. That same atmosphere that lets you brake and/or parachute down, is a literal drag when you want to lift something up.
Still, Mars has higher gravity--and if you build a beveled spinning ribbon, you can simulate Earth-normal gravity easily. So the crew won't risk going osteoporotic from a long stay.
An async skyhook would provide an additional martian transport system. One that "touched down" every couple hours or so would give you a circumferential up/down navigation sequence. You could thus have multiple settlements which grow to become hubs. Think of it like a train, one that just happens to actual go up and then down instead of across the surface. It would be quite a way to get more out of the investment as you could use it for cross-planet transportation when not using to to launch or receive long-haul cargoes. Personally I think asnyc hooks are a better choice anyway because of the multiple-location aspect.
Regarding asteroids vs. meteoroids I'm going to have to disagree as one of us is using the term incorrectly. My education holds that meteoroids are too small for mining as they are generally only a few meters across, and often much less than a meter. Of course, back then Pluto was a full-fledged planet so that definition may be too old. However, the bulk of the inner and middle belt asteroids are believed/known to be heavily metallic. These are the "Bright S" and "Bright M" class asteroids. The former are composed mostly of metallic iron with silicates such as magnesium (hence the "S"). The latter are primarily made up of metallic iron (thus the "M"). Ultimately, for purposes of rotation mass (such as in a tether), as long you can manage/contain the stresses it doesn't matter much.
Regarding launching from the moon, sure you benefit form lower gravity and no atmo, but it doesn't make up for the costs of building and maintaining a system there. The moon has some distinctly more difficult and costly environmental problems than Mars does - y0u pay a price for having no atmosphere. The mass you have to take to the moon is dramatically more than for Mars. Whereas on Mars you can get away with, for example, with growing food under millimeters of thin plastic on Luna you're talking very thick glass - measured in feet. Of course, the 28 day day/night cycle would pose other problems - problems that preclude solar power for a moon base. Sure you could set up by the poles, but that isn't where the goods are.
Almost everything you need to build that catapult on Luna you have to ship there. Martian rockets and fuel can be built there. The shallower gravitational well means we can can use less energetic (and volatile) fuel quite effectively.
Until we have something like fusion you can't generate the power on the moon to reliably grow food for a population of any significance. This means a lot of money in importing basic goods - a lunar settlement before a Martian one is a financial gravitational well (and probably after, just less of one). However, Mars we already know has nearly all of the resources to build its infrastructure. The only thing you will need to import much of at first is high technology such as computer tech and the more refined materials - all of which tend to be rather lightweight and functionally dense.
Lunar does is another massive hurdle. It gets everywhere. It is ridiculously fine and very abrasive. And by abrasive I mean enough to wear through three layers of space suit boot. It got into everything, causing problems from moving suit arms to "lunar hay fever". Any mining operation will exacerbate this problem radically. Trying to clean it with wet wipes only made it worse due to their charged natures. The thermal swings are very large, which causes additional problems. Even maintaining a consistent temperature range is rather difficult on the Moon just as it is in orbit.
Lunar bases require a massive increase in requirements and mass, for little to no gain and none compared to the Martian environment. Sure, it has h3, but currently h3 has no real value plus to get it you need to ship in masses of h2 and apply metric captions of energy - making it possibly not cost effective. Even before we manage to control fusion, deuterium is already very valuable and Mars has it in abundance.
Looking historically, if Earth is Europe, the moon is Greenland and the Americas is Mars. Sure, it took longer to get to North America than to Greenland, but it was done because that is where the resources were.
We are left only with the longer transit time--which pretty much guarantees that Mars will always be a separate polity.
A Free Mars has the potential to replicate at a planetary scale what Free America did at the continental scale. Once I started comparing the possible space ward bound scenarios to history it was quite shocking how close some are. This time around, however, our "Columbus" has to seek the support of producers, rather than governments.
Now if I understand you correctly, the costs of building such a vessel in geostationary orbit would be far greater than the cost of first establishing Martian colonies and then building that super-vessel in low Martian orbit, not Earth orbit.
If we then put this together with the Free Mars proposal, that would suggest the first mission this super-vessel would fly, would be a rescue mission for Earth-bound "producers" seeking to defect. Or did I miss something?
But unless we had teleporters or other orbit-to-earth mechanisms a "rescue" mission would be hard to pull off without terrestrial supporters getting them to orbit; a task a bit more difficult than an "underground railroad". Though I suspect there are enough well-funded producers who, upon seeing a free planet where they can thrive, could put the resources behind it.
More realistically we'd be building the tether transport system and/or nuclear-electric "cyclers" not too dissimilar to the one used in "The Martian". I'd expect we'd mostly hold off on operations near Earth for political reasons; no reason to rustle native's jimmies. That said, a pure spaceship with any level of defensive/offensive capability would be a strong defensive play and could generate significant appeal - and fear. Being of the independent-from-Earth mindset we'd most likely use such a vessel to increase our independence in the material sense in the beginning. The less dependent on terrestrial exports we are the better a position we are in for any economic negotiations with terrestrial exporters - and governments.
Though having such a ship could trigger terrestrials trying to build one of their own the sheer cost of it would delay its actual production. It would take them much longer since they would have to ship everything from Earth. Then they would need to develop "space legs": experience which we would already have. I very much doubt there would be much support for launching a nuclear strike against Free Mars.
Even so, we'd be better off with focusing on an orbital defense grid in Mars orbit for a non-aggressive defense posture; only adding offensive capability if the terrestrials got aggressive. It would be rather difficult to launch a sneak-attack from Earth to Mars and any incoming craft would be trackable and almost sitting ducks given the predictability and limited approach orbits and vectors. Of course, our ships that transferred to/from Earth orbit would need some defensive capability as those would be the primary vectors for aggression.
If history is an accurate guide, technological development on free Mars could quickly overtake terrestrial - particularly in the very technologies needed for space travel and defense. A Free Mars space fleet would have the advantage of space-based resources, and thus would be able to have significantly more mass. This mass would be useful for shielding and could be combined with powerful mass accelerators ("railguns") for weaponry if needed. Terrestrial ships would be very hard pressed to keep up - especially with Martian fleet having all the space maneuver experience and adaptation.
What the producers would need to develop is not a teleporter. I believe that would be impossible--or at least I know of no theory of physics or information science that would make that remotely feasible.
No--we would need a universal lander. A small craft, about the size of the now-retired STS orbiter or maybe considerably smaller, that could take off like a conventional airplane, climb to the high troposphere like any airliner, then engage a rocket that would boost it into orbit. That same engineer I mentioned, who talked of building a space-to-space ship in orbit, talked of a landing craft that could also land on and take off from the Moon or Mars.
Mars does have one problem Earth does not have. Its magnetic field is very weak. That would leave anyone on the surface more vulnerable to cosmic radiation. Mars is, of course, much farther away from the Sun than Earth, on average. But still: all cities on Mars would need electromagnetic radiation deflectors, in case of solar flare.
Concerning resource development, the best direction to look in would be beyond Mars, but not much further beyond: to the Galilean Moons of Jupiter, and Titan, the largest moon of Saturn. I doubt you're going to find anything on the other rocks except water ice, and the elements of topsoil--or regolith. The water ice actually would be twice as rich in deuterium as are the oceans of Earth. That applies to every extraterrestrial object. The race would thus be on to develop controlled fusion.
Solar flares are likewise of little concern to a Mars surface dweller. The planet and atmosphere block out most of their radiation. Relatively simple sandbag roofing under a dome can reduce it even further, to the extent that under a small sandbag level roof a settler would only experience about 3 rem during a flare. Fortunately we know in advance and have warning time to get into even more secured areas for the minor duration of a flare. So we have no need of electromagnetic shields, err fields, to provide the protection needed.
Now as to fusion development, what we know currently points to deuterium being a key ingredient. Mars' concentration of which is roughly six times the level of seawater on Earth. So once we figure it out, we don't need to go looking elsewhere for the fuel. Which ties us back into the original topic. ;) Deuterium last I knew was already running at over $10k per kilo (or was it pound? IDR). I can only image what would happened to the price if demand for it suddenly shot up. And with mars having a "high' concentration of it, it wild be come a very hot commodity indeed.
Yeah the teleporter was a tad tongue-in-cheek. A lander would be needed, but that lander has to come back out of the gravity well. At that point we're back to the cost/problem of getting off of the Earth's surface.
It could be based off of a Martian hopper - a VTOL "hopping" coat which uses rockets to go up, "slide over" and go back down. Quite handy for local travel and feasible because of the plentifulness of fuel supply and lower gravity.
The base would need a system to replace Earth-normal gravity for the living space. That other engineer I told you about, envisioned a beveled wheel, spinning at such a rate that the normal force would be one g, a resultant from 0.37 g straight down and 0.93 g horizontal centrifugal "force." The construction crew would be working in low-g conditions--but I believe you could compensate for that by literally having them lift heavy-enough loads by themselves to give their muscles the same workout they get from walking around on earth. Less heavy equipment. Not only is muscle cheaper, but the sandhogs need the exercise.
Make sure, though, to use full-spectrum lighting in the finished base. I might suggest incandescent lighting, using a new technique someone developed at MIT to recapture some of the energy now wasted as heat. Incandescent light has a spectrum more beneficial to human health than do soft-white LED's. The key: you want to replace, as much as possible, the daylight from Earth. Fiber-optic skylight systems can help, I think.
If the people of Earth want to be reasonable, they can build an anchored skyhook that will cut down on the lifting costs. Manufactured goods come up; deuterium and tri-alphium (helium-3) go back down.
The essential sequence is to build a large transparent dome - as large as you can. We can relatively easily ship the initial domes from Earth. You start with 50m imported domes (under 12T in mass), moving on to manufacturing 100m+ sized domes. Then under that dome you build like you normally would. The first buildings would be masonry using Mars dirt. Later you'd use natively grown bamboo and eventually smaller trees. A caveat to that, I suspect, is having fans to provide wind for the bamboo and trees to naturally strengthen, though with the lower stresses in lumber that may not be necessary. This will provide the physical effort needed to minimize the loss early on.
That said, you can leverage the actual gravity to maintain high muscular/skeletal stress on mars via good old fashioned weight lifting. You just have to lift more mass to reach the higher stresses. No need for a complex spinning system when we can set up a gym and build masonry buildings. We already know that you can increase the body's gravitational stress adaption over normal local environment - we call them bodybuilders. There is no reason to expect it to not work the same on Mars.
You can't "lift weights" in space without simulating gravity, but on Mars you certainly can. It might even be possible to maintain the higher strength those born and raised on Earth would initially have.
However, in the medium term I'd expect allowing the body to adapt to the gravity would be more beneficial. A lower body mass means lower caloric and oxygen requirements. This places a smaller burden on food and oxygen consumption, thus extending the value of the crops and atmospheric conversion systems already in place.
For lighting, I agree on full-spectrum for the main human areas. However, by building and living under a transparent dome "outdoors" from the housing built under it would provide direct sunlight on a regular basis as well. I'd expect skylights in the housing to keep daylight power consumption down as well as more natural light - just as we do here.
Regarding the H:D ratios, there are several papers on it, but of course they are all behind member-walls but there are articles referencing the 6x of them. I'm sure I can dig one or two up if you want.
That really is the key to settling Mars - being able to simply do what we do here.
Of course I would recommend using plain old-fashioned human muscle as much as possible for all building projects. That saves at least some of the cost of shipping heavy equipment.
But the price of simply adapting to 0.37 g is still high. It limits the bodies where one might visit. That applies not only to Earth but also to Venus.
"The one thing no space agency has ever even thought to deal with, is gestation and parturition in a low-gravity environment." Not quite.
While we have no data on it in humans, remember that a fetus gestates in a functionally zero-g environment. This is why a fetus can be upside down for weeks on end without the problem of blood rushing to the head and causing injury.
Indeed the data we do have is on nonhuman studies, the problems found were in adjusting to Earth's gravity. Note these tests were done in orbit, thus without the effects of gravity at all. There is no reason to believe an area of lesser gravity would be worse.
Jellyfish in space! Nope, not joking. http://www.sciencedirect.com/science/...
Note that jellyfish evolved to live in a micro-gravity area - the oceans, and that their problem when moving to Earth was that they did not develop their "microgravity receptors" - something they did not need in orbit. These are creatures who are very susceptible to microgravity because that is what they use to determine up versus down - something crucial in Earth's oceans.
We've also set pregnant rats up. The main part that we saw "underdevelop" was vestibular. This also makes sense in that this ability is less important in orbit - and possibly a case could be made that it would be detrimental. However, we saw no neuroanatomical differences, and got some surprising results. The two primary factors considered were "righting behavior" and tilting the head. In a gravity well tilting the head up alters your blood pressure and heart rate as the body accounts for the gravitational shift this produces. Right tests were done in contact based, and aquatic.
Initially the rat pups had a delayed ability to right themselves. However, by the end of the first week of life, this was entirely gone in all cases. The first time their head was elevated, they had a resulting change in heart rate, but no tin successive ones. This shows rapid (and unexpected by the authors of the second study) adaptation to gravity. It should also be noted that the pregnant rats were more angularly active rather than linear (gravity).
While we've not yet done the test, there is evidence to support a theory that rats gestated and born in orbit would be adapted to the environment from birth. Their angular receptors and processing were higher and the urge to "right" themselves was initially nonexistent. Of course, in a true 3-d environment this makes sense. Indeed lacking the more linear driven receptor and impulse could be very beneficial for that environment.
A primary cause of space emotion sickness is the fact that we develop for 1G and a linear driven space. Our brains don't properly process what we see versus what we feel. However, if human prenatal development were similar to rats, then it is quite possible native-born "free-spacers" would likely be generally immune to the effect. They might also function more effectively. Personally I thin that would be a fascinating time in human evolution and would lead to a branching of the species as free-spacers evolved biologically adapted to zero-g. Native floaters would be more sensitive to angular momentum changes such as twisting than to a linear gravistatic change.
We did fish way back in the 70s. Earth-born fish had a few days of freak-out called "looping" but adjusted and swam normally unless you shook their bag. The native born fish had zero swimming problems. All spaced fish had looping episodes and adaptation to Earth gravity once landed. No fish have ever vomited in space. Terrestrial fish transports report fish can indeed vomit due to motion sickness.
I think fish studies are particularly enlightening because of their ability to ge emotions sickness while also having two primary up/down mechanisms - one gravity based on the other visual - just as we humans do. In fish the visual is light sourcing where they will turn their back on the light because that is "up". Not all, but most, fish tested do this.
The Japanese did "vomit comet" runs with a the medaka breed of fish to find ones which didn't loop, then bred non-looping fish. Personally I think that is incredibly cool and interesting. They then took these fish to space where they mated. A lot. That is what medaka do - mate daily. There were eggs visible less than 24 hours after launch.
While the adults had to adapt to life on earth, the offspring did not - neither the 11 fry born in space nor the remainder that finished up on Earth. These fish had zero problems breeding, gestation, or (in the case of the kids) adapting to Earth. There is reason to believe that given a few week post-adjustment non-selectively bred medaka would mate in space as well.
We know, now, that epigenetics can cause a dramatic change in a short time. Indeed in the most recent rat gestation in orbit study I am aware of there were hints at epigenetic effects which is why they visually recorded the mothers movement to provide a comparison of behavior.
This is one of the things that intrigues me most about what we discover regarding adaptation and gravity. The more we learn the more it makes sense in an evolutionary context.
So yes, we don't have hard data on humans, yet. But the data we do have on both fish and rats, and worms classified as animal, as well as some insects, do not give reason to believe it substantially problematic. Naturally our tests have been on no-G environment because we aren't on Mars yet.
Of course, on Mars we do have gravity. So the "answer" is logically between those two research extremes. I would project that since most of our linear adaptation occurs after birth, we would still develop it. Much of the gravitational effects are likely more binary than relative since the primary sense around gravity is up versus down.
Indeed the main concern regarding reproduction in space is 1) the method and 2) space radiation. We've already slain the radiation dragon regarding Mars, and well, Mars' gravity is certainly enough to allow our normal human experience to work as it always has. The lower gravity of Mars may well have positive results for the mother as the effect of baby weighing parts of her anatomy down during late term may be lessened.
That virtually all results of what we have tried demonstrate consistency with evolutional expectations, I'm bullish on the notion.
suspicious0bservers.org has a lot of these links and discussions.
As far as our behavior is concerned, awareness and self control seems to be key. (this is my work to this end)
This, of course, will be AFTER they outlaw the disposal of any spent fuel that might be created.
Kevin Fong (Extreme Medicine: How Exploration Transformed Medicine in the Twentieth Century) expressed many fears about the effects of low or no gravity, and higher radiation, both on the journey to Mars and life on Mars. https://www.wired.com/2014/02/happens... He placed his hope in artificial gravity. To be sure, much of his discussion talks about micro-gravity, not the 0.38 g of Mars. How much gravity is enough gravity? Fong doesn't say.
The Mars One project, which talks hopefully of sending people on one-way trips so they can spend their lives collecting and studying samples and reporting back to Earth, has this article on flight safety concerns.
http://www.mars-one.com/faq/health-an...
The chief way they recommend compensating for lesser gravity, is exercise.
Ars Technica has this article about long-term adaptation to the Martian environment.
http://arstechnica.com/science/2016/0...
They express concern that Mars lacks a magnetosphere, and speak of radiation either causing a new species, or merely killing the colonists or condemning them to live in permanent shelter.
Space Safety similarly discusses the gravity effect:
http://www.spacesafetymagazine.com/sp...
If you subscribe to Quora, you can read this discussion on the subject:
https://www.quora.com/Can-humans-live...
Here's another article from Live Science:
http://www.livescience.com/33082-woul...
This discussion on Stack Exchange asks the question you and I are really discussing: how much gravity is enough?
http://space.stackexchange.com/questi...
I'd like to break out the discussion into three phases, so we can discuss the problems of, and solutions for, each. They are: the flight to Mars, the initial settlement-building project, and living there long-term--I mean very long-term. Decades. Centuries, if Robert A. Heinlein was at all correct in his own speculation (The Moon is a Harsh Mistress) on low-gravity, or low-er gravity, living.
First, the flight to Mars. Anyone traveling to Mars, even if one-way, must sustain his bones and protect himself from radiation on the way. From what I've read, the best protection against radiation is not a leaden bulkhead or hatchway, but a magnetic shield. Robert Winglee (Advanced Propulsion Laboratory, UWash)
http://earthweb.ess.washington.edu/sp...
proposed a magnetic solar sail to drive a ship. I find the thrust minimal, but his magnetic generators would be just the thing for a radiation shield.
The gravity is another thing. Notice that every article I cited suffers from the same flaw. They speak of the deleterious effects of having no gravity to speak of. 0.38 g is not zero. The question is now to get the crew and passengers there and have them able to start working as soon as possible, without having to drink lots of raw milk that in any case would be sour once you got it there. I suggest building a ship in the form of a cylinder, or a saucer housing a centrifuge. Or if you don't want to wait that long, launch a pair of modules, one for habitation, the other a counterweight holding your initial construction materials. (Heavy equipment, not so much--I'll get to that.) Tether these together and spin them for 0.38 g, and at least you'll be simulating the Martian environment. (Spinning for Earth-normal gravity might require a ridiculously long tether, or a spin that would produce a noticeable Coriolis effect.) And make sure every member of the crew exercises regularly. Strength training, too.
Some wags at NASA did talk of a continuous-acceleration transit. I find that a prodigious waste of fuel. Even rigging for spin to simulate 0.38 g is better than that. Ideally, the crew could bring along consumables for a long, lazy Hohman transit, or better yet, build their habitats with gardens that can provide fresh vegetables and regenerate the oxygen. And: recycling. Is. Paramount. Especially for water.
We come now to living on Mars, and why I expressed hope the crew would not need a lot of heavy equipment. Muscle. Is. Cheap. Not only that, but simple ergonomics might demand high-muscle-strength tasks. The only reason for any equipment heavier than shovels, picks, mattocks, etc., is to save time, and to build skyscrapers. Time is of the essence, because the crew must take along, or ship ahead, oxygen and fresh water supplies that can last until the construction gang can build greenhouses for regenerating oxygen, and (depending on where they land) find water, or at least ice. And I recommend: everybody works, and everybody does some heavy lifting. They have to keep their strength up.
And so we come to long-term life on Mars. This presents a city-planning problem and facing whether to adapt permanently to a light-gravity environment. If the city that I would call Areopolis hoped to host anyone who came to visit but not to live there, they'd have to build a centrifugal habitat, as I designed. And even if you wanted everyone to remain adapted to Earth-normal gravity, I wouldn't object to building a medical complex with a light-gravity ward, for the treatment and management of patients suffering from chronic heart disease, for instance.
No one is going to know the adaptive effects of light-gravity living, and whether those changes are all to the bad, all to the good, or simply "work out better" one way or the other, until you have a population willing to do the light-gravity thing all the time. Best to build the beveled, spinning cylinder for the "control" population and let the "experimental" population continue to live, work, and exercise in the native light gravity of Mars.
In any event, we do have a radiation hazard. But I'll allow that another variation on Robert Winglee's magnetic solar sail would be ideal to keep the radiation to a minimum. I don't want to enclose people and subject them to artificial lighting alone. A transparent dome, with a magnetic generator to augment whatever shield the planet itself provides, would serve better. And make sure to have full-spectrum lighting throughout.
Martian industry, like city building, would de-emphasize heavy equipment and favor plain ordinary human muscle, perhaps with draft horses to augment this. As before, muscle goes a long way in a light-gravity environment. Furthermore, muscle wants to work--that is how muscle stays strong.
As you can see, I have a few doubts about long-term effects. But I also see a few solutions, including some that make good economic sense. Who would have thought, with the invention of tractors, steam cranes, and whatnot, that the humble draft horse would ever come back? Or that ironworkers, sandhogs, and other high-muscle working people could do so much more even without so much heavy equipment to operate and, more to the point, maintain?
Finally, I've given you what links I could find. I'd like to see some links to your own sources.
Before we get into the science, let us look at the common thread in the links you provided. My advice on anything from "Mars One" people is to ignore it - they really don't know what they are talking about. Enough so that I am inclined to think it a scam, but refrain from assuming that because I also don't like making such conclusions absent good data for it. They mix in accurate stuff with fundamental flaws. For example, they correctly state that dust storms are not a wind hazard due to the difference in pressure. A 100 MPH wind on Mars would be a gentle breeze. However, in that same article they claim Mars' dust storms make solar not-so-viable and we don't have nuclear reactor capability to send to Mars. This is absurdly false on both fronts.
While our slowdown of nuclear research (politics) has slowed our understanding, the fact it we've had the ability for decades doesn't change. There is a large contingent of people in NASA, who are not nuclear physicists and engineers, opposed to nuclear research for political and funding reasons. Sadly this effect persists throughout NASA and in science more broadly. Probably because most scientists don't study economics. ;)
But back to the links more broadly. None them use the known research. All of them propose spending large amounts of money to solve problems in a more complex way, or to not go at all because the author doesn't know something. The former was a hard lesson for me to come to grips with.
Take magnetic shielding, for example. There are two camps in the industry on flight time shielding: one wants money for research on new toys and the other sees the problem as solved well enough to move on. Those who want money to spend on researching magnetic shielding ignore the basic fundamentals. First, we aren't protected from cosmic and solar radiation by Earth's magnetosphere as much as is publicly assumed - we get it from the fact that we have a big atmosphere and planet. At sea level on Earth you receive on average around 150 millirem annually. In Aspen, Colorado you get twice as much. For cosmic radiation the major mitigating factor is the sun, not Earth. Low earth orbit has about half of the cosmic radiation exposure you get in interplanetary space - because the planet is physically blocking about half of background levels.
Because of long duration stays on the ISS we have astronauts who have logged more radiation exposure than would be received on a round trip to Mars. In some cased double the radiation dosage a Mars return mission would get in total (travel on surface). None have experience radiological based side effects. I've found that this isn't surprising to the people in the nuclear research industry. We have a lot of data on the effects of radiation at various levels on humans and there is nothing novel about radiation on Mars or in space. Radiation simply isn't the problem the media, or those who want money to "solve it" with more tech likes to make it. Magnetic shielding sounds sexy, and maybe someday we will have it. But it isn't needed.
The real radiation risk during spaceflight is a big solar flare. We've handled this problem. Indeed we solved it back in the sixties. In the event of flare being detected the Apollo crews were to go into the lander which had higher shielding. The data we have on Apollo flights and flares showed that the lunar lander was more than sufficient to protect them from the largest flares we have ever recorded. With existing basic craft design and materials, the largest flares on record would have delivered to an unprepared Mars-bound passenger abut 38 rem. Humans don't get burst-rad sickness under 75rem doses. Any sane interplanetary craft would have a "shelter" behind the stores to reduce that, of course, and we have "early warning systems" so there would be little to no reason the travelers should be unprepared for flare. By stacking food and water stores we can reduce that highest-ever recorded dose level to 8 rem. Anyone telling you 8 rem is too risky and dangerous is either ignorant or scaremongering.
For Mars, the levels are easily tolerable. Consider https://www.nasa.gov/jpl/msl/mars-rov... to look at measured levels:
"The observations have been almost entirely due to galactic cosmic rays, which contribute a slowly varying dose rate of about 210 micrograys per day. Variations are due to day-to-night differences in the shielding provided by the atmosphere. "
Now, a microgray is tiny. On a sidetone IMO much of the confusion around radiation is the fact that we use so. damned. many. ways to measure it. Above I mentioned 75rem as the dosage where radiation sickness begins. So who does the above compare? Well it depends on the type of gray! However, in general 3Gy is ~300 rad (yet another term!) and is considered a high dose, though more than 1 Gy is known to start the bottom end of rad-sickness effects such as nausea and blood changes. So the above recording my Curiosity rover - entirely unshielded BTW - recorded around 210 micro-Gy with a peak of 260 due to a solar particle event (a solar flare). So unprotected real-world measurement shows it to be well below illness-inducing levels. Using http://www.aqua-calc.com/convert/radi... we can see that 260 micrograys we can see that since 1 µGy = 0.0001 rem for gamma radiation then this translates to roughly 0.026 rem. That is no cause for concern.
If we consider high-energy protons the conversion is 1 µGy = 0.001 or about .26 rem. Again, well below dangerous levels. the long-term risk is in slightly elevated risks of cancers - more so among women than men. But again here the medical data on radiation exposure long-term shows this risk to, for example, raise a risk from under one percent to under one percent or sometimes to 1.6 percent. I'll point you to Chernobyl. This was a case of large exposures to a comparatively large group or people of various age ranges. Despite what we in the west might have done, much of the affected area remained inhabited despite the radiation levels. http://www.world-nuclear.org/informat... is one starting point that shows it isn't the problem we've assumed it to be. Indeed, consider one if the "main lessons" from the worst radiological accident in human history: "Psychosomatic disorders and the screening effects were the only detectable health consequences among the general population."
Yet back in NASA-land, despite Curiosity explicitly showing the unprotected exposure levels are not a problem, we somehow need to send more robots to figure it out. For this, lets look at http://www.space.com/23875-mars-radia... which concludes at the start that radiation isn't the risk some insist it to be. The data collected clearly shows this to be the case, but we might somehow find different results if we did it again, so we need more missions to repeat it. They mention that these (again, unprotected) levels could statistically increase your "risk" of developing cancer by 5%. But they leave out that a 5% increase in a single-digit percent change is really tiny. If you had a 10% chance of developing cancer, and saw a 5% increase in it what is your new statistical chance of getting cancer? 10.5%. However, what is not mentioned is that this is a cumulative risk - where we look at a variety of cancers, calculate a statistical increase, then sum up that increase and get to 3 or 5 percent increased total risk.
According to BEIR estimates, every 100rem above natural Earth exposure levels equates to a 1.8% overall increase of a fatal cancer over 30 years. Basically assuming a non-smoking healthy individual with an Earth risk of fatal cancer at some point in their life is 20% then to raise that to still less than 21% would take an exposure of ~18 rem in flight followed by decades of life on Mars. Technically yes, that is an increase. Is it problematic? Not in my view. More specifically, the risk increase in leukemia is .3 percent. Yet as we saw w/Chernobyl the actual increase has been zero. This actually makes sense when you look at the raw numbers rather than the X% increase absent the amount it is applied to.
Now on the effects of "microgravity" - a term which is unhelpful because people use it to mean "anything less than 1G". You'll see the term used in describing ISS, Skylab, and SS missions but also applying to the gravistatic environment of the moon and Mars. Here again we have the jockeying for funding affecting NASA. The fact is we have limited data on anything between orbit and 1G. We have limited bed-rest studies which can replicate partial effects on earth, but those are too limited to be of much value. We are replicating the effect, not the cause, and I think we can both agree that the cause comes with other effects ignored.
So what we do is apply basic reasoning. Let us consider 1G one end of the spectrum, and 0 the other. Mars is at .36 on that spectrum. So we have worst-case and "best-case". I think it entirely logical that Mars is in-between, and I am sure you'd agree. So what are worst case knowns?
First: muscle loss. This is a known, and solved problem in zero-g. Resistance training limits this problem. We have astronauts able to play tennis within days of returning to 1G because of resistance training. As noted earlier, basic physics shows us that all of the resistance solutions we have come up with for orbital environments are irrelevant on Mars where we can simply lift weights - something you are absolutely spot-on about with physical labor. Now that said we've had maximum strength loss of 30% and muscle mass loss of 15%. Even prior to resistance training on-orbit astronauts recovered to 1G in days. It stands to reason that "recovering" to less than 1G would take less time than to a full G. Of course, we don't need to do that.
A simple tether system has been shown to be effective. We've got a pair of non-habitat spacecraft still in orbit which are tethered and rotating - and have been doing this for years without fail. As such a simple counter-weight tether for interplanetary travel providing some level between .38 and 1 (or more!) is a solved solution. Of course, when people think "artificial gravity" they are almost always thinking of Star Wars, Star Trek, or BSG style. But we've already proven mathematically and experimentally the we can use tethers to produce long-arm, low-RPM (i.e.: 2 RPM) with a tether to a counter-mass to provide a full 1G to interplanetary travelers. Now, I'd recommend we go with initially providing .75 to provide a transition period to Mars-Standard gravity, decreasing as you get to Mars. For counterbalance you can use the otherwise discarded booster stage, which you then discard when done with.
So the removes the long-term zero-g environment concern entirely. If we are OK with astronauts on the ISS going for eighteen months in zero-g, we can't really complain abut even 8 months of zero-g in transit to Mars, let alone somewhere in between the two. This reduces us the Martian gravity levels. Given we know the extreme of 0 is manageable, it stands to reason that .38 is as well.
When you talk to astronauts, they will tell you the situation around zero-g adaptation is well understood and overrated. We have literal reams of data on this. Most of it is offline because it hasn't been digitized - gotta spend the money on more research! Ultimately, as you hinted at, the only thing that will matter is people being on Mars or in an equivalent tethered station in LEO. But at that point, why not simply do it on Mars? You mention an experimental population and a non-experimental one. This is post-colonization. The first, say, 50 years of martian settlement will be oriented completely around adapting to and building the settlement - not catering to people concerned about lower gravity effects and returning to Earth. Counter to some claims, tourism is unlikely for quite a while. Thus for the settlement of Mars, an increased gravity environment is unnecessary and indeed I would argue is wasteful.
IMO, which is open to change, a better use of those resource would be to build the surface-to-orbit tether I talked about earlier. With this you open up easy travel around Mars, and easier travel between orbit and surface. Now in this rotating tether, which can literally bootstrap itself with low tonnage, you have the means to go from surface to a spinning platform. The ability to provide a high level of gravistatic environment is a side-effect of the mandatory spin to power the tether in the first place!
Now this is where Phobos comes in. It actually has a use, the more I think about it. With the tether providing very cheap access to orbit, we also have cheap access to Phobos. Now on Phobos, we build a receiving elevator tether (non-rotating) to get from orbit to Phobos. On the "outside" of Phobos, which is tide-locked to Mars we build another elevator. Now we have the ability to send stuff from Mars to orbit to Phobos, to anywhere else really damned cheaply. Plus we have a place where we can actually assemble a fully-rotating space station! Personally, I find that to be phracking cool. Plus, that tether now becomes the inbound destination for craft from Earth or the belt, rather than Mars orbit. Thus, the delta-v to get to Mars, and the mass required become much smaller. The craft would need no aeroshield, no drogue parachute, and minimal thrusters to match the angular velocity of the "external" tether tip on Phobos.
Anyway, back to the effects of sub-1G. There is one actual problem when considering a return to earth: bone density decrease. In absence of a gravistatic environment bones lose calcium heavily. We've no found an exercise regimen which loads the bones in a 0G environment. However, as noted above, we aren't talking about living in that environment. We don't know how much loss would be a problem for Mars, and there is only one way to find out. However, it stands to reason that as bone density is a function of gravistatic load of the skeletal system as a whole, that the loss would continue to the point it is needed on Mars. We do know that in a gravistatic field weight training increases bone density and decreases loss (as in elderly concerning osteoporosis). One study of many can be found at https://www.ncbi.nlm.nih.gov/pubmed/9... and any search for osteoporosis and bone density will yield a trove of information showing the effects. In essence, we know the solution for bone loss in a moderate gravity environment.
Now as to more references, as I mentioned earlier much of the work was done prior to digital publishing and there is no real budget/effort at NASA to digitize them. Most of what has been done is only available behind the member-walls and paywalls. For example:
http://jap.physiology.org/content/81/...
http://www.comprehensivephysiology.co...
https://www.ncbi.nlm.nih.gov/pubmed/9... (mentioned above)
http://jap.physiology.org/content/91/...
Two key things you'll pick up from physiology research is a) they are trying to mimic gravity in a non-gravity environment and thus have to work around this, and b) they are concerned with the making return to Earth easier. Since we don't have the conditions for (a) to limit us, hard work pays off dramatically as you've noted, and (b) is not a concern for the settlement of Mars, the extremes found in free-space are not to be found on Mars. We already accept the extremes for ISS occupation. Thus, I think it reasonable to conclude that the risks for Mars are lower and thus at least, if not more, acceptable to those who would take them.
Ultimately the only way to get hard data is to put someone in the environment. For the money and risk it would take to put someone in an equivalent environment in LEO, we could put them on Mars. When you ask astronauts you get almost universally, that they'd rather be on Mars doing it than in LEO. I've even asked high-schoolers which they would rather do, and again almost universally (though less so) they prefer the idea of doing that on Mars.
The work of Robert Zubrin and Richard Wagner is very well organized and referenced. I'd recommend a second edition of "The Case for Mars" as a solid collection point. He only touches on some of the points we've discussed but goes more in depth on the radiation and gravity effects. The references are often not online directly but can be obtained with effort. One of the only-briefly touched upon aspect is the tethering system. So far I'm the only one I've found advocating for building a tether based transportation system from Mars - probably because it isn't seen as "sexy" nor involves metric tonnes of research money. We've figured out the materials science, we've figured out the mechanics, and we know what needs to be done. The hard part is actually done. Also probably because, at the risk of hubris, not many take the longer term view I do.
On that note I really want to express my gratitude for your involvement in this discussion. Your questions and perspective have helped me, almost forced me in a good way, to crystallize some of the stuff that has been at my periphery - such as the Phobos aspect. It also pushed me out of where I normally look. For example I've not paid much attention to the HASTOL experiment because it is terrestrial. However, a key element of it is also very applicable to martian tethering and elevator build out - the self-feeding nature. I'll need to do some work (mostly math) on minimums needed to start with usable "bites" and determine growth rates, but it does neatly solve an early settlement problem, along with some others. Plus it provides the path to the Phobos relay. I've been meaning and wanting to put together and publisher a larger "plan" that takes off from the point of being able to get to and bootstrap martian settlements on the cheap - a problem we've really already solved, but alas bootstrapping launch capability has always prevented me - it just felt missing. Now I am re-invigorated and excited - which admittedly has been a bit lacking for a few years.
Thanks to you and this discussion I feel I've now got somewhere to go with this, and thus I offer my sincere gratitude. So feel free to keep asking questions if you want, I welcome them enthusiastically! :)
I would still recommend, for the flight out, a simple tether system for getting people to Mars. (Zubrin's Mars Society recommends that, too.) That way, they'd be fully acclimatized as soon as they were ready to deploy the aerobrakes. The flight crew would also be in better shape to accomplish the landing, because they would have their reflexes fully adjusted to the task.
Just to be clear: to me "microgravity" means zero or near-zero--say, whatever the astronauts feel while their ship is under thrust. The Martian and lunar gravity levels, I call "light" (or maybe "ultra-light" for the Moon). In light gravity, as I said before: muscle is cheap. It makes sense to replace heavy-duty winches with block-and-tackle assemblies with plain ordinary human power as an energy input. That's just one example. In every way possible, let's have human beings do the heavy lifting. It will keep them strong and save having to ship heavy equipment ahead.
Here's another thing you might not have considered: livestock. Will the colony need any? The two uses for livestock are food and draft. The main reason to carry and raise draft animals is that they might be easier to take care of than heavy equipment. That, and serve as a source of fertilizer.
When it comes to food: I suspect, thought I cannot prove, that the vegan lifestyle, with vitamin and mineral supplementation, might have more bang for the payload gram than our conventional eat-everything diet. That means a diet of fruits and vegetables--including garbanzo beans and other concentrated protein sources.
Companion animals might be a problem. Dogs and cats are out. They are meat eaters. How are you going to feed them? (Well, maybe we'll allow cats, and prepare food from snakes or mice.) Even rodents--rabbits, groundhogs, squirrels, and such--would compete with the humans for the fruits and veggies.
Back to that other bottom line: as you say, we cannot know what compromises human development might make until people actually live full-time at 0.38 g--by standing on Mars without a centrifuge. I'll take you at your word: for fifty years, the people will have a city, or cities, to build, plus at least one skyhook. Plenty of ways to get exercise, from the work itself. And I meant that about the universal rule: everybody works. Cardio machines--stationary bike, elliptical machines, and maybe treadmills--for supplemental electric power, and using human muscle whenever possible for the physical acts of building. Yes, I said supplemental electric power--for a small-scale nuclear reactor would do quite nicely, with some supplementation from sun and wind.
"Here's another thing you might not have considered: livestock. Will the colony need any? "
Absolutely! Indeed animals are crucial to developing a fully-fledged agricultural foundation. Hoover animals are actually pretty good at soil maintenance - from tilling and trampling to, as you say, pulling a plow, but also in terms of fertilizer production. If we look strictly at energy conversion animals are poorly suited. But, as with life, the answer is more interrelated than that. The biological process and biodiversity you gain are quite valuable and much more difficult to replace. One neat thing about the larger livestock is the ability to essentially use weight training on them to give them more muscle power than the natural martian environment would provide - somewhere between Earth and Mars, giving them more utility in that regard.
As to diet, vegan would be a terrible plan. Vegan diets are detrimental to cognitive capability, to reaction time, and to cyclic food store survival. At least those first two we will want settlers to have in peak performance rather than dulled. Also, the inclusion of animals brings the biodiversity level up which is critical for robustness. Vegan sources of proteins are insufficient for the task without heavy supplementation from Earth. I could go on about the "diet" options, but that is a discussion at least as large as this one!
No horses initially, but cows, goats, pig, sheep and a few fowls like chicken, along with some aquatics like tilapia are all on my list. Mid and long term the use of the above "standard farm animals" have additional uses including well, think Little House on the Prairie if you're old enough. Much of the meat of settling Mars is really homesteading once you get the dome(s) in place. it is cheaper to import hydrogen feedstocks than crates of clothing. Fabric and leather is freaking heavy, as the movers found out when they got to my wife's seeing room supplies. :D We are actually very good at utilizing pretty much the entire animal, which becomes even more beneficial on Mars. But don't think of it as competition for food.
For example you can, and should, feed a cow on grass which humans won't eat. Grass is quite easy to grow and manage, requiring little that a (small) herd of cows or other ruminants don't provide. Humans can't eat it, but it provides biomatter, food for cows which provide fertilizer (think of bone and blood meal, not just the patties), leather, and tallow - each of which has any uses. This is part of why Zubrin is absolutely wrong on Mars needing a million specialized working people to be "self sufficient". No society starts out with fully specialized people, it needs a lot of generalists and base tech from which it grows. Multi-use is very advantageous, and maybe critical, to establishing a settlement. In the research project we even went so far as to consider toilet paper sourcing and feminine hygiene products.
For me I tend to think about it like my wife and I took on our new (functionally smaller) kitchen we moved. We wound up decreasing our bevy of single-use tools in favor of fewer multi-purpose ones because it saved a lot of room. Each use doesn't have to be perfect, just functional and not painful or problematic. Good enough really is good enough.
The tricky part is really the transfer between planets. I've laughed myself light-headed a few ties at the image of a cow with its legs stuck straight out floating around in space eyeballing the walls but tethering solves that "problem" anyway. But we do know we can transport and gestate at lest some mammals, fish, insects, and probably fowl in orbit safely. Maybe we could repeat the Japanese fish study and selectively breed cows that have a better tolerance for free-fall, or maybe we start by sending younger (and thus smaller and more adaptable!) ones first.
Either way, it doesn't really seem that insurmountable. Of course, you send enough pre-packaged food to last if the first batch or two of cows, for example, don't work out. But you will need animals for a viable agricultural system on Mars. You do need to account for lesser mass in a native-born animal, but the really important parts of most animals are the fatty bits, from organs to marrow and the lovely marbling of the meat. And mmmm bone broth.
Plus, this "industry" is a capability that doesn't require high-tech, is well known, has wide ranges of success, and can use human power. Heck even have some electric sewing machines for under-dome clothing, blankets, furniture, etc. made from locally-sourced animals would be far more cost-effective than relying on shipping the finished products from Earth. Sometimes I amuse myself by imagining a colony of Quakers or Amish in a few 100m domes on Mars. But it also makes me think about what we actually need and how we can do things with lower import requirement and more bootstrapping.
And yeah, everybody works is absolutely crucial in the first decades. The availability of an agricultural base expands the ease of contribution. Even children can take care of animals and make usable products from plants and animals. Mechanical engineers can sew or knit, or make furniture. It even gives you pastime options - something important to psychological health.
An undertaking as large as a settlement needs only a few true sophisticates, namely the transport crews. You need at least one, preferably two, skilled pilots aboard each transport. Between them they must combine the functions of boatswain (in charge of rigging and so on), coxswain (to steer the ship and bring it in for landing), quartermaster, and communicator. Each officer should also be trained in first aid. It would help to have a flight surgeon on board, but we're probably talking general practice and "telemedicine," in which a handful of doctors in the fleet can coach people on the other transports, even through surgery if they had to.
But other than that, you would need the most humble occupations you can imagine. Farmers and animal husbandmen, of course. And masons. And ironworkers.
This also reminds me of another movie from early in this century: Armageddon. The key scene: Bruce Willis' oil drillman character finds out that NASA want to send a bunch of their usual test-pilot astronauts to operate a drill. And they don't even know how to put the drill together. The chief drillman convinces NASA that it's easier to teach oil drillmen astronautics than to teach astronauts how to drill in rock. Which is how they handle it.
Say--do you think you could use wood for any application? Isn't the Martian atmosphere incredibly rich in carbon dioxide--96 percent? And what better carbon sink than a forest? You mentioned furniture--why not use wood for furniture or even flooring, interior wall trim, and so forth?
I would agree with sending calves, piglets, etc. I still recommend horses, as draft animals. A good draft horse can pull more than a plow. Substitute literal horse power for motors, and you've got yourself a way to keep the animals exercised, and a good source of slow-but-steady motive power.
I keep coming back to the interplanetary transport problem. As I see it, interplanetary transport is a compromise between delta-v and consumables. The easiest transit to calculate is the Hohman transit--an ever-so-gentle elliptical orbit that jumps off from Earth and intercepts Mars, with very little delta-v for trans-Martian (or, on the return, trans-Terran) injection and orbital insertion at destination. On the other hand, you have to carry usable oxygen, or else recycle as tightly as you can imagine. Now here I'm thinking mainly of how to carry in the second or third wave of settlers, plus any supplies and equipment they want to bring with them. Build a flying "bolas" consisting of two gently curved platforms, one at each end of a rigid tether--rigid because at the center of this rigid tether, or mast, you have a hub holding engines, sensors (mainly cameras and radar), and a complete reaction-control system. The pilots don't have to sit in this hub--they can sit on one of the platforms and steer this odd-shaped ship from there. Such a double platform could carry any kind of specialized modular transport you can imagine, plus extra fuel, oxygen, and a foldable dome that could enclose all the modules and let people leave the confines of their transports during transit. It could carry more than a capsule you would put on a heavy-lifting rocket, or a skyhook climber. It could also carry the kind of universal lander I mentioned several messages back: a craft that could take off like a conventional aircraft, fire rockets to boost it to orbit, then fire another rocket to intercept one of those double-platform transports and "land" on it. While on board, they can re-fuel--and at Mars they have their own ship to enter the atmosphere and land in much the same way as they took off--though probably on a much longer runway. This is not that super-ship I first talked about--it serves only one purpose, and that is to get a few planeloads of settlers from Earth to Mars so they can take an active role in expanding the city and eventually building that super-ship.
On the transit craft, you could indeed have two important parts at each end of the tether, but I feel safer with all the good at one end and otherwise "useless" ballast at the other. If the tether were to break I'd rather just lose my artificial gravity for the remainder of the trip than part of my ship and/or supplies. Especially the in the early launches mass will still be at a premium and the fewer redundant systems such as a way to recover the "other half" doesn't seem to me to be worth it. Especially if I am looking to bootstrap a tether system. I'd say the first dozen launches, at least, will prioritize landed mass over reusability. But on the Hohman transit orbit, absolutely spot-on. This is one of the reasons behind the Phobos outside elevator(s) - that is precisely the transits they are best suited for. Then with the initial surface-to-low-orbit tether building itself (it has roughly two years between import cycles initially) and a few test you can cut some of the mass and delta-v requirements from incoming rockets thus increasing the usable delivered mass.
Of course to help that along we'd also be sending some payloads (almost assuredly unmanned initially) back using the tether. From there I'd split transpiration and manufacturing focus on expansion of the tether, an additional base, and gearing up for orbit to Phobos tethering. A second base has the obvious benefit of serving as "backup", but can also double "launch" capacity from the surface. Say the first tether has a "pause-point" on the surface every two hours. This would give you about 13 spots along its path around the planet, and for simplicity assume no repeats (there are designs that can hit the same location twice per day). You can only send one shipment at each touchdown. But if you have two stations, you can now ship something twice per cycle. I need to do the math and research on a double-ended hook to see if you could add an additional cycle in there thus cutting the distance between terminals and doubling the number of sites.
But ultimately, all else being equal, you get twice the to-orbit production by splitting the same output capacity among two terminals. Or you could do a little bit of specialization - maybe another site has better access to a specific resource through expansion.
Among that initial need will be the production of dome material and solar panels - both of which Mars has the right stuff for in pretty good measure. I'm thinking of first doubling the same-site dome count, then building up to start a second, if smaller in scope, site and prepositioning the materials. I think while this approach may not be as efficient as focusing on making a bigger single-site settlement, there is psychological benefit to it. Knowing you have a second site ready provides some comfort. You can also then "go visit" other people by hooking up a "shuttle" to take you to another station. I believe this would help ameliorate the feeling of being so far from the rest of humanity.
It also provides "proof". See, personally, I'm happy with someone like Elon wanting to provide the rockets to get you to "my" planet. But I want to the guy who (in part) is the real-estate developer on Mars. Every full dome you can produce on Mars - and get to an independent site, is less mass to be transferred from Earth and more "see, we can do this". Who knows, maybe an Amish or Mennonite community might find the travel in exchange for more isolation worthy of selling off their terrestrial holdings to pay for the trip and start-up - then we'd have the ability to trade, and a community of craftspersons!
Or perhaps some universities would get together (after we've established the surface to phase relay and external elevator) would be interested in leasing or renting out a site for some research. It isn't inconceivable for them to get together and do it. Some of the research might even decide to stay. It also thus provides an income flow from Earth to Mars. It becomes cheaper to get there, and you can send more higher value goods. Especially goods such as satellites and an almost-super ship.
A cycler ship isn't a bad idea, just not one for right out of the gate. But once we have surface to Phobos and the external elevator for Mars to belt, venus, Luna and LEO we can build our first massive earth-bound export - a tether for that end. I say export but only in terms of mass, I'd expect "us" to manage and operate it - and thus charge the fees. Now once we have this, we can build a cycler. A craft that only goes from interplanetary tether to interplanetary tether. This is pretty close to that super ship. Using materials from Phobos and Mars we can build the shell, furnishings, fuel tanks and fuel, water and food tanks, and supplies. We then "cycle" it to Earth with a crew.
At Earth it meets up with the high-quality goods such as computer systems, some Earth supplies and maybe some people or a nuclear rocket (hey I can dream!). The crew then has the return cycle to work on integrating the terrestrial systems into the martian craft. Then as needs and production meet you can add to it. You get the bulk of the mass from the rendezvous with Mars, and the high-tech pieces, and cargo, from Earth. Of course if we do have cargo for Earth it can go along. Or maybe we build our second one. Two is more comforting than one big one, after all.
For times when Mars & Earth are not close, we can send low time-value cargo - up until we have enough shielding to not be worried at all about some crew or passengers being in transit for a year or so (now about those nuclear rockets ...). It is funny; I see dismissive arguments against Mars being the time it takes to get there - even if we have awesome shielding - being an end-all factor. But if that were the case, we would not have crossed the Atlantic a couple hundred years ago, now would we have? It took around two months to cross from England to America. Anyway, I don't want to get too sidetracked as you have some excellent other questions.
On wood, that was actually my first analysis task - well wood vs bamboo and what we would need to do either. Bamboo is treatable like wood, and in some ways easier to work with and grow. You can use a long bamboo culm as-is and in torsion structures easier and with less mass than tree based lumber. They also grow quite fast compared to most trees. Technically bamboo is a grass but most wouldn't know it from wood in the right applications (such as bamboo "hardwood" flooring at Costco). The lower growth requirements and greater flexibility in early constructions lend bamboo a distinct advantage. Bamboo is (depending on which kind) prolific and doesn't have the root requirements of trees.
On trees, we do have some good candidates from a pure lumber aspect such as pawlonias - a very fast yet strong tree you can cut down and watch it regrow. They are also very prolific in seed output and easy to get going. But, trees do give me a concern in the early days. We've learned that wood is so strong because of the wind forces acting on it during its growth - it essentially rebuilds itself adapting to the wind. The wind's effects on the upper tree structure form leaves to branches is "pushed" though to the trunks and roots. In order to replicate that we would need the large domes to have a semi-controllable (ie. containing within reasonable limits) chaotic wind mechanism. Since we know we need it, but not exactly how, I'm a little leery we'd get it right early on. Of course, with the lower gravity and lighter structures it may not matter. I'd probably still take some seeds if possible. Experiment early, experiment often!
But on the other hand we have bamboo which while it is strengthened by wind during its growth, it grows strong in very low wind areas and its structure doesn't produce the wind loading that a tree does - this isn't as dependant on it. I think this gives it an advantage in having a greater margin for error. Plus it produces lighter structures. Some of it is edible, too. But wait, there is more! It is a natural pipe. Ok, not a lot more, but it is something.
It might be possible to use it to cheaply and simply create sharpened hollow spikes you drive into the ground through which you pipe hot saturated steam. This steam then becomes part of the local permafrost to provide a very solid anchor as long as you still have permafrost. That is all speculation on my part, but if it worked it would be a significant advantage in that it is little refinement for such a gain. I also would love to see testing on bamboo (and wood) in the same temperature range we'd see on Mars but that isn't terribly easy to get funded so I don't see much likelihood. Thus, both bamboo and wood testing would probably by something undertaken in situ by settlers.
Fortunately, the most important aspect of either bamboo or tree logs is still present - the ability to sit under a clear dome on a clear black martian night with a nice campfire, some marshmallows, and the most amazing view of the stars any modern human could ask for. Then when you've had your rest, you get back on the tethers, ascend to your tall ship and steer her by the nearest start to pick up more people and cargo.
In looking up Hohmann transits, I found this article from Scientific American:
https://www.scientificamerican.com/ar...
They propose what they call an alternative, but it reads to me like an extension: ballistic capture. That means you calculate a transit that will put your spacecraft near enough to Mars, and just ahead of Mars in its own orbit, that Mars will catch up to it and capture it. Such a transit makes aerobraking easier, hence less expensive all around.
I suspect, though, the author makes the same mistakes you cited earlier, about worrying too much about the radiation hazard. He writes:
"For manned missions, ballistic transfer would be a mixed blessing. On one hand, its longer journeys would add to the challenges of ferrying people to Mars. We're already worried about Mars-bound explorers driving each other crazy stuck in a tin can for six months, not to mention soaking up unacceptably high space radiation doses. For that reason, robotic missions look to be the first potential beneficiaries of Belbruno and Topputo's new low-energy transfers."
Hm-m-m-m. It seems to me you had the solution to that problem, or maybe we each had a different solution, and our solutions could work in tandem. So what's he worried about? The stir-crazy aspect? I've seen the Mars Society habitat design. That baby isn't an Apollo Command Module. It's large enough even to have a laboratory and an infirmary. With slight modification, like maybe another deck, it could have an observatory. Plenty to do, and if everyone's on the same page, the crew should be fine.
But has anyone tried to calculate a permanent shuttling orbit between Earth and Mars? That is, an orbit that would intercept Earth and Mars at regular intervals? It's easy enough to inject into an orbit that has its apoapsis (or aphelion, to be precise) at the average orbital radius of Mars, and its periapsis at the average orbital radius of Earth (1 AU). But can we calculate that so that the orbit intercepts Mars and Earth at those respective points? I had in mind that the payload transports jump onto the ferry platform at origin, ride it during the transit, then jump off and insert into orbit around the destination planet. The transports would expend the delta-v, but at least a human crew would have the benefit of a comfortable gravity. And remember: the ferry platform could carry extra fuel and consumables. That might not seem much of an advantage, but I figure the ferry could provide a permanent solution to the problems of artificial gravity and radiation shielding. It would even allow a higher class of repairs en route.
Remember our original scenario: the Earth-bound governments--or maybe the UN-IPCC--start the project as an ostensible way to solve the global warming problem. Then, in the middle of the project, they write it off. But the Martians fool everybody, prepared as they are to become self-sufficient as rapidly as any settlement can. Then you come to what I had in mind: a large group of refugees take off in "universal landers." If they had a ferry platform to jump onto, they could then negotiate for the fuel to land on Mars, or at least get near enough to the skyhooks to ride down. Such vehicles as they have would even give them a good bargaining position.
I can well understand using bamboo instead of traditional wood, for all the reasons you raise.
Since you mentioned nuclear rockets, I do remember the NERVA program. No one ever followed up on it. It would have been the heavy lifter to end all heavy lifters, but no one dared use such a rocket in Earth's biosphere. But that super-ship I mentioned earlier, could use Nerva engines if it ever wanted to get somewhere fast.
He also fails to understand we already put humans in a tin-can for more than a martian transit and have been for years. Now, as we've seen the radiation isn't the dragon he thinks, but I'd be leery of extending the most radiation-intense portion by 25% or more. We'd have to get a lot more bang for the buck and I don't see the case for it.
Ahh NERVA. A sad casualty of our political anti-nuke BS; on of many. NERVA, or nuclear rockets in general, gives you two options: a shorter transit time (and thus a bigger window), or more payload. You don't get both, and the duration increase isn't the halving one might expect from the payload double option. If it were available, I'd go with more payload. There was work done on gas core versions of it which were able to obtain three times the thrust duration (up to around 3,000 seconds of firing IIRC) - which is where you get the double payload or increased speed. There also increased risks with going faster.
Now about the refugee scenario. If we combine the export of a tether system to Earth orbit, it might be possible to use HASTOL as the shuttle. With what we know now, landing a lander on Earth that will then pick up cargo (people) and come back up is a monstrous undertaking. But if the they could get a hold of a mach 12 plane capable of meeting up with the tether. ;)
In the scenario it would depend on when in the process the break occurred - it is crucial to determining what options are available. Which is one reason you want to focus on being able to replicate the habitat and set up the initial tethers as soon as you can. Also, if Musk and Co. aren't on Mars by the time the break occurs, and they have their HLV ready/able to send just people and cargo to LEO in large amounts, that could be the breakpoint in favor of refugees.
And yeah the Mars Society's hab design is pretty neat, isn't it?
http://www.tethers.com/papers/HASTOLA...
Your variation on the scenario depends most heavily on who controls the skyhook: the space-borne civilization, or (for lack of a better setting) the UN on Earth. I gather you figure if people can get off the ground, the space-borne folks control the tether--because a rotating tether stays in orbit and has no anchor to the ground. Hard to figure on the "interplanetary law" angle--unless we just say that possession--defensible possession--is nine tenths of the law.
So let's assume we're the Martians and we control the skyhook. If I read that HASTOL paper correctly, the aircraft is supposed to meet the skyhook, let it hook onto the payload (which could be a cargo or passenger module), then let go. The skyhook sweeps the payload aloft, and the plane goes back down for a landing. In a refugee-rescue scenario, then, the flight crew would place their plane on autopilot, join the passengers in the module, trigger a remote control to release the module when the skyhook hooks on, and let the plane flame out and ditch in the ocean. Correct? Or could anyone possibly build a plane that could take off and let the skyhook carry payload, plane and all aloft? That would almost be a requirement--or at least would be far more convenient. Because the pilots could shut down their SCRAMjets (the best model I can think of for an engine that can achieve Mach 12) and use rocket thrusters to jump onto whatever kind of ship can meet them and carry them out to Mars.
About powerful rocket engines: I agree that delta-V and payload mass present a compromise. I also know that, given the equation for energy (the capacity for work), twice the thrust would translate either into carrying twice the payload, or increasing maximum speed by about forty-one percent. Energy varies directly as mass--and as the square of speed. So yes, I would carry double payloads. It would be an inherently more efficient use of the bigger engine.
Concerning confinement: to be scrupulously fair, the ISS is a maze of tin cans that together have as much total room as a Boeing 747. But the quarters are still cramped. Zubrin's habitats have room enough to stand up in, and at least three decks: laboratory/sick bay/airlock, control country/galley/lounge, and living berths, in order from lower to upper. I should think the crew could at least feel that they had more room even than aboard the ISS.
Back to skyhooks: I assume now that you propose the Martian low-orbit skyhook would swoop down and snag a payload from ground level. Do you have in mind a rail sled that would accelerate the cargo to the speed of the hook? How fast would the hook travel? Would the hub carry thrusters to add back whatever speed the hook lost on each passage and especially with each load? (Surely you're not proposing a perpetual-motion machine.)
Yeah, in this fictional scenario with the intent of the would-be colony to get the free-thinkers out where they will die and "leave us alone", I doubt there would be much work in laws about it. Alternatively, since the colony would have either succumbed to the obvious failure of not accepting governance by the enlightened and perished, or the government simply cut us off, I'd expect they would not have any control over the tether anyway. Particularly so since tethers would initially be unmanned, possibly turning into small habitable space over time - much like small towns develop around interstate rest stops. Either way the arrogance of the looters would leave a wide opening to use the earth tether(s).
HASTOL is pretty heady and complicated stuff, which is why I don't see it as something simple enough for all but the technically brightest remaining; hence someone like Musk in my example scenario. However, assuming the refuge scenario you've got it right on how it would play out unless the pilots were of a more heroic archetype and thought they could get at least one more flight in. I don't care what math you want to throw out there, making a rendezvous with a skyhook at mach 12 isn't for the casual pilot or unsteady hand.
I also just realized I forgot to answer your question about calculating the cycler orbit. Yes, it has been done a few times. The best summary I can find - which actually lists some results is at https://en.wikipedia.org/wiki/Mars_cy.... As you'll see from the wikipedia link, the best case is an embark/debark rendezvous occurring every two years or so - about the same as sending rockets in the prime windows. The advantage comes in having more than one and in the delta-v coming from the cycler rather than the launch systems on either end. In Aldrin's proposal you'd have each one having complementary orbits where when one has a 5 month transit to Mars, the other gets a 5 month transit to Earth; they then each spend nearly two years outside martian orbit.
Personally, as proposed I find that latter bit wasteful. I also forgot to mention on the bolo cycler design the you actually want the thrusters at one or both ends of the bolo, rather than the middle. You need work on "pull" thrust under tension.
On confinement, there is some amazing work done by Christopher Alexander on how large or small a given space feels, and most of it has to do with how many steps it takes to get from purpose to purpose (such as the kitchen counter to the sink, or the bed to the bathroom). Stairs (and one would assume ladders) tend to extend how one feels about distance. Thus a have with tether-gravity that has multiple floors will, cubic foot for cubic foot, feel larger. Sure the total cubic space of ISS is large, but it is the individual areas you work in that the brain localizes the sense of proportion to. I've been in naval vessels, mainly submarines, that had a lot of cubic space and felt tight and cramped. Same thing w/a B52 btw.
Now, back to hooksville! Yes, the martian surface hook reaches down to the surface. The best illustration, I think, is https://en.wikipedia.org/wiki/File:Cy.... The calculations I've done and with some crosschecking with others, show we can do it with no acceleration needed. This is because the relative velocity between the hook and the ground station is zero. This leaves the sudden acceleration to be considered next. Fortunately that is determined by your arm length and how far up you need this first stage tether to go.
For my async tether I'm looking at an orbital period of 2.62 hours "touching down" 6 times per orbit. From the point of view of the ground station the tip/pod visually comes straight down, pauses, then goes straight up. From the point of the view of a pod getting hooked from the ground, all acceleration is straight up. This acceleration is .49g for Mars (pluss Mars' .38 for a total of about .87g.
This is well within tolerable; heck we go to amusement parks for far more than that. It is a somewhat tight window, I'll grant that. But there is only one moving part and you know exactly where it is going and how fast. You could probably have faster/longer ones which require say a 60 m/s velocity. At the top end you can get to a 1g tether bet here you're looking at 500 m/s velocity so there you're back into rocketsville to get to it. Sure, the is still easier than on Earth but ... it is still around 1100-1200 MPH or about Mach 1.5. Easier in Mars atmo, but more to bootstrap.
Incidentally the above 'hook made of Kevlar is plenty strong and would need to possess total mass of 1100 x max payload - assuming a safety factor of two. But we have Zylon, M5, and Spectra 2k which are both stronger and lighter - I still need to run those calculations someday.
Now another option is to also incorporate Deimos with its larger orbital period and thus higher angular velocity. You'd go surface to Phobos to Deimos to wherever. While they don't share a plane, the two moons orbits take them close enough that you can transfer between the two with almost no delta-v needed - and Deimos out outside stationary orbit. Most people like the tether-to-rocketplane approach for reasons I'm sill flummoxed by. For Earth the reasons are obvious, but not to me for Mars (or the moon for crying out loud).
To me since we have the materials for it, the maths, and the tech and the greater simplicity of ground station it just seems to make more sense. Maybe we like rockets and magnetic launch too much. Maybe I like elegant and simple solutions over big and cool too much.
Nonetheless, Weinstein proposed one from Phobos to the edge or martian atmosphere which would have a relative velocity to the ground of .52 km/s, provide 1g to cargo, and give you two windows per day 60km above the ground.
Now his system is different. It consists essentially of a series of cable connected platforms. Not to dissimilar fro a ski-lift. You'd transfer cargo from cable to cable at each section joint, and travel around 100-150 MPH meaning it takes a couple days to get up or down to those points. But a smaller one you can transit to after a tether pickup ... Anyway, getting sidetracked again. Onwards to stationkeeping.
So clearly for tethers hanging off of the moons the mass is enough to keep station so long as we aren't shipping large asteroids through the setup. But the rotating hooks do need a form of stationkeeping. There are two primary avenues. First, if you send equal mass in each direction you balance it out. Not technically perpetual motion, since it is fully valid physics. The other it post-use thrusters. These can be slow and efficient electronic thrusters.
The math on it generally works out to a rue of thumb of periodically shipping in propellent which works out to be around a 10% margin. By that I mean if you figure a one-way tether with that type of thrust you're looking at a "surcharge" of each payload being 10% - or every 10th pickup is all fuel. Of course, every cargo run "the other way" reduces this. The earth tether can leverage an electric tether to account for it.
Oh and yes, for the belt we pick big asteroids and put tethers there too. ;) You get a tether, and you get a tether - tethers for everyone! Then we start building powered bolo launchers - think space railgun to boost cargoes to 30-100 km/s velocities.
Then in few decades later we start building these at Mars: https://en.wikipedia.org/wiki/Orbital...
Just to blow the Earthers' minds muahahaha >:D
edit: oh and we routinely have submarines submerged on missions for four or more months though most are around 90 days. The limit is food stores. That is cramped.
Turning now to transits between the Martian surface and its orbit: yes, I can see that the tether could easily swing its hook down so it would be nearly stationary for just long enough to hook onto a cargo and swing it up. It would take precise timing and co-ordination, but we can manage that well enough. That works to get a cargo up. Now how do you get one down?
I haven't asked too many questions about the Phobos skyhook. As I recall, Phobos has a shorter sidereal month than the Martian sidereal day--so that Phobos rises in the west and sets in the east! So how would a tether work with Phobos as an anchor?
Concerning confinement: as I thought, a vessel with multiple decks feels less confining than a vessel with one deck or especially with one room. That conforms to my own experience. I have lived fifty-nine years in various dwellings, some with more space than others, and arranged in all sorts of ways. The only problem with a dwelling with multiple floors is negotiating the stairs.
All things considered: obviously a Martian society will survive, even the worst-case scenario of abandonment--and be in good case to declare independence.
And I agree on one other point: I prefer my solutions technically simple. It saves time, resources, and effort.
So Phobos, the core idea is you can put (multiple) hooks on each side. It is tide-locked so the same side always faces the planet. It is sub-stationary orbit as well. You don't take it down to the surface because its orbit is off-center, thus you need a smaller version of the rocket plane. But in my view Phobos' advantage is in interplanetary catch and release. On the upward side you run a 6,000 Km cable to which incoming craft dock with and outgoing ones release from.
For outward bound craft the elevator 's tip has a velocity of 3.52 km/sec would result in a hyperbolic velocity of about 2.6 km/sec. This is the Hohmann elliptical transfer velocity needed to reach the Earth/Moon system, and is also nearly the transfer velocity needed to reach the inner edge of the asteroid belt. The interior cable can reach all the way to the upper atmosphere but with the surface picker it doesn't need to.
The interior(s) one would be sized to reduce the delta-v needed to transfer from pickup to Phobos and the reverse. Most Phobos elevator ideas say the same thing on going to the surface: "Just roll off the side and fall". But then you still need shielding and landing equipment and supplies. With a LMO<->surface transporter we can move more effective cargo.
A HASTOL escape scene would make for a thrilling part of a movie, certainly.
Here's my problem. The nearest I have to a report that mentions payload and seating capacity is this report for the Airbus A320.
http://www.airlines-inform.com/commer...
It quotes a max payload of 18.6 metric tons and a seating capacity of 180 in a one-class configuration. The problem: as I understand it, commercial airlines count seats as structure, not payload. But in designing a 14-ton module for hooking onto an LEO tether, seats are part of payload.
You might have sources I don't have. The question becomes: how many passengers could a single 14-metric-ton module comfortably carry, with provisions for a five-month transit and allowing for whatever raw materials they might bring with them so the Martians don't regard them as freeloaders?
After I sent my last message I anticipated your reply. You have to roll until you're belly up, match speeds in orbit--a forced orbit, too--hook on, and ride it down. I assume if you time the release just right, the module doesn't have to brake, or at least not too hard. It seems counterintuitive, but that's the tale the cycloid tells.
So Phobos becomes the hub for an intermediate step between the surface and an interplanetary trajectory. The LMO skyhook gets you into orbit, and Phobos can fling you out, with minimal burns for setting the transit you want and correcting it en route.
Phobos also gives you a way to launch a cargo on a Hohmann transit at the same interval as the inbound Aldrin cycler. Again, no need for that inbound cycler, because you don't need to "ride the sled."
It would also make a great way to play out the scene where another John Galt says, "The transit is now cleared. We are returning to Earth."