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So, some sort of solar-powered microwave oven rig can cook water out of fairly-saturated soils. Interesting. I'd guess any explorers/settlers ought to take a bunch of these with them.
GW
Spacenut -- my sentiments exactly!
A manned vehicle on a long voyage would have 3, maybe 4, intervals where burns are conducted during the one-way transit. You are not spinning during these burns, you have to eat "astronaut food", and use "zero-gee toilets", and accumulate wastes in a zero-gee holding tank, for those brief intervals of hours to maybe a day.
During the long coast intervals in between, you spin up and enjoy normal Earth food and normal Earth toilets. You do normal Earth cooking. Your waste treatment equipment can be Earth-normal, which is one whale of a lot easier to design and therefore far more reliable.
Antenna pointing problems from a spinning ship can easily be avoided, by a small fly-along antenna module that does not spin, but has a short range omni repeater that you can easily receive in your spinning ship.
The astronaut hab module(s) can be like the Bigelow illustrations we have seen, just with the decks inside rearranged. Because the propellant mass and volume so far exceeds the crew volume, I doubt we are looking at a wheel-shaped hab. That puts us into the baton that spins end-over-end, with the hab at one end. You just use multiple Bigelow-type modules, and trick them out inside differently, to be what they need to be.
If you do it that way (spinning Baton), the decks will be cross section planes inside the cylindrical modules. You size spin rate and radius-from-cg to put 1 full gee at the farthest deck, and make that the day shift work space. There will be a gee gradient radially inward. Make the innermost decks your supplies storage, and the decks just below that sleeping quarters, since sleeping prone confers no gee benefits to health. That might be in the neighborhood of half a gee at the sleeping quarters deck. And that's just fine.
Even untrained civilians can tolerate 3 to 4 rpm long-term. At 4 rpm, the radius to 1 gee is only 56 meters. Given crew sizes of 2 to 6, your ship will likely size out near 150 m long at reasonable baton L/D ratios for a Mars mission. And by "reasonable", I mean structurally-sound: too skinny is too flexible, too weak.
It all works out just fine for a very reasonable rough-out design, actually. We're talking vehicles in the 300-600 ton class for a crew of 6 to Mars, chemical propulsion. Most of that by far is propellant.
Rigid baton vs cable-connected: baton is far more dynamically stable, and easier to control, during spin-up/spin-down operations. The rigid baton encourages modular design, especially with a reconfigurable stack of propellant tank modules. After each burn, you stage-off some empties, and just redock the remaining tank modules to maintain an acceptable baton length at an acceptable L/D and an acceptable spin rate.
A safety consideration: if your baton takes a meteor hit, it doesn't come apart. You just de-spin and patch the hole before you lose all the propellant in the struck tank. If you are cable-connected, and the cable takes a meteor hit, it breaks and you are unrecoverably dead, lost in deep space without propulsion. Also, tanks (and your hab modules) can be covered with foam-and-foil layered meteor "armor" that also doubles as very good insulation. It's hard to imagine how to add meteor armor to a cable.
All those things conspire together to tell me that the spinning baton is the right way to do artificial gravity without building "battlestar galacticas" no one can afford.
To get that same benefit on the surface of Mars, different constraints apply. I haven't thought my way through that problem, but a rotating deck, shaped to a conical angle matched to the spin rate, might be something one could build and operate within some sort of stationary pressurized building. Sort of like a big, slanted, circular moving sidewalk.
The same spin rate limits (3 to 4 rpm max) and gee requirements (one full gee because we know no better) do apply. But for a slanted "moving sidewalk" design, the vector geometry is conical. You get to add the centripetal acceleration to Mars's gravity vectorially. That vector sum should be the one full gee. That vector diagram gives you the right slant angle, too.
GW
Quaoar: I don't really know what payload to stage diameter ratio is used, but visually it looks like 1.5 is a reasonable number.
Space construction yard: There were right and wrong things about how ISS was built. Docking modules is right. Using a launcher 100-1000 times to expensive to send them up there was wrong (shuttle at min $27,000/lb and usually far higher, vs commercial at $2500/lb).
Part of the huge ISS expense is expected, in that all of the the ISS modules were one-of-a-kind items. In "general vehicle construction" this does not have to be true. You can adopt a modularized approach and standardize the modules, and then use them for multiple vehicle designs and missions. Then they are not so very expensive over the long haul, as you get to amortize their development costs over several different projects.
But it does require that you think ahead, have a long-term plan, and stick to it. That is something NASA has not had since end-of-Apollo/start-of-shuttle. They have had no long-term plan, just a series of political footballs kicked to them by congresses. (No better with ESA, either.)
GW
Now THAT is an interesting idea (freezing out the CO2 to counteract greenhouse warming). I haven't got a clue as to how to figure out if it can work, much less how to make it work as a practical item.
Wow! Neat idea! First reversible geoengineering proposal I ever heard of! Reversible things are actually worth trying.
GW
For a given atmosphere, variables affecting entry gees, end-of-hypersonics altitude, and peak heating rates are (10 entry speed, (2) entry angle relative to horizontal, and (3) ballistic coefficient. Higher speed, steeper angle, and higher ballistic coefficient all act to increase gees and heating, and to decrease altitude, very sharply.
Entering from low circular orbit does two very beneficial things: (1) velocities are inherently low enough to eliminate the risk of "skipping off the atmosphere", and (2) entry angle is inherently very shallow, unless you are extremely wasteful in sizing your deorbit burn.
A pretty good sizing approach for the deorbit burn is the burn needed to take you into a surface-grazing ellipse. More is wasteful, much less might be ineffective.
Maneuvering around between high orbits low orbits, and elliptical orbits, costs propellant which must be dead-headed to Mars as payload for the outbound trip. In fact, it costs quite a bit, which is what my "Mars Mission Study 2013" posted over at "exrocketman" found.
The lowest circular orbit stable for the requisite time seems to be the best overall choice for missions that stage out of orbit, so as to make more than one landing in the one trip to Mars. That's probably somewhere near 300 km altitude on a 1-year time scale, maybe nearer 500 km on a multi-year time scale.
GW
RobertDyck:
You were right about cold temperatures in Winnipeg. I had the local weatherman, an aquaintence of mine, look up historical records. Feb 1 and 2, 1996, they were -41.8 and -41.2 C. That's -43 F. So the -85 F figure was a wind chill. Now I'm no longer sure of the -61 F figure for Embarrass, Minnesota, those same mornings. Those were supposed to be actual thermometer readings.
Where I was in Mankato (40 miles off the Iowa border in southern Minnesota), the -31 F was a real temperature. The wind chills had been reported as -70F to -80 F all the night before, but the real temperatures were -30 F (-34 C) class. It was 40-knot windy. Those temperatures were unusual record-setting lows for that vicinity.
All of that was a real education for a Texas flatland boy who had never before lived anywhere north of Dallas. I came home to Texas with a taste for airconditioning after that experience.
I did see the other day where a satellite thought it saw Antarctic high plateau temperatures of -136 F (-93 C) last antarctic winter.
GW
Biggest problem with aerocapture/aerobraking schemes is the factor-2 variability of Mars atmospheric density profiles at high altitudes. Your design has to allow for this, so it is not as simple and lightweight as you might think at first. They had to allow for that with the probes that have used it, in the sense that the differences get partly made up at lower altitudes by lift during entry, and the rest "lost" in the uncertainties of chute deceleration.
Big items to be landed on Mars will not find chutes useful, as they penetrate to too low an altitude for a chute to deploy, much less do any deceleration good. That leaves retro-thrust rocket braking as the only practical terminal landing method.
I think for aerocapture, you will have to accept a factor-2 variable outcome, and carry the orbital maneuvering propellant to make up for it. For aerobraking, you will have to carry the extra propellant to make up the uncertainty in your retro-thrust rocket-braked terminal landing propellant.
Either way, you will be carrying extra propellants. Propellants that could do direct braking or orbit modification anyway. You won't save as much at Mars trying to use aerocapture/aerobraking as you would think at first glance. It is the density variability at high altitude that causes this dilemma.
Earth's atmosphere does not suffer this kind of variability at high altitudes, which is why we had no prior experience with it at Mars. It's why the landing ellipses were so very large on Mars, until very recently.
GW
I like the Bigelow inflatables. I like seeing how the pressure shell is unobstructed by mounted equipment. This enables a fast patch if punctured, rather than evacuation/depressurization as with Mir. The advantage of the inflatable isn't weight, it's shroud diameter for launch. If only heat shields could really deflate and stow like that.
The big rocket would be nice, if the commercial launch industry developed it, not the government. Period.
You put the Falcons, Atlas-5, and Delta-4 on a plot of unit cost vs payload size, and you see that a launcher capable of 100+ tons to LEO should cost under $800/lb or $2000/kg. You look at NASA's historical costs with Titan-4 and NASA's projections for SLS on that same plot, and you see unit costs 4 to 10 times higher than they should be. Titan never got the commercial redesign that Atlas and Delta got. Those two no longer resemble their roots as government ICBM's used as launchers.
The civilian government (not just US, none of them) knows nothing about simplifying rocketry to reduce logistical support tails. The military knows more about that, but does not generally deal in launcher-capable rockets any more. That's simply a sad fact of life that must be dealt with intelligently.
Congress demonstrably does not deal with anything intelligently any more. That problem appears erratically over historical time, and actually predates the Civil War, which is why we had one. That's also why a way-too-expensive SLS (and all the other designs before it) were mandated upon NASA, needed or not.
Atlas and Delta fly for around $2500/lb in the 15-20 ton class fully loaded. Falcon-9 is about the same at 13 tons. Falcon-Heavy looks to be about $1000/lb at 53 tons. A fully-loaded commercial 130-ton payload rocket should be around $500-800/lb; unfortunately, there is not such a thing.
If SLS fully loaded really is near the projected $4000/lb fully loaded in the 100+ ton class, and I think it will be that high or higher (maybe as much as $8-10,000/lb), it will never be affordable to use for any of the potential missions that might use it. Period. You are simply far better off financially by launching smaller stuff with the commercial rockets and docking it together in orbit.
GW
I see good ideas here for desalination by freezing, the same way the ocean does it with polar pack ice. The concept is easy, getting equipment that produces mass quantities quickly is very hard. You don't do that with "a small chamber".
Lest you dismiss "mass quantities" as a Coneheads comedy issue, quantify how much water you are going to need every single day to support, say, a dozen folks in a permanent base. Add to that water needed for making rocket propellants, especially if you want to make a suborbital flight to another site every month or so. That takes tons, not kilograms, of propellants.
How "easy" or "hard" something actually is has a lot more to do with what quantity-rate ballpark you are playing in, and a whole lot less with exactly what scientific principle you choose to employ.
GW
Hi Tom:
"I don't think every rich person is a criminal, this is a rather unfortunate attitude to have." -- I never said they were. But observation over decades does show that every significant pirate (word choice? those who achieve by depriving others) is rich. That's exactly how they got rich. There are many other rich folks who are not pirates. We have one or two right here in Waco. Good folks, they are.
"The main problem with the docking bay of the station of 2001 A Space Odyssey was that is was rectangular," -- this kind of docking bay mentioned as a concept, not a specification of shape for actual design. Many shapes could serve, and circular is quite probably the easiest to build. Circular would not be the easiest to close, if the bay were to be pressurizable. If not, that one design problem goes away.
GW
Hi RobertDyck:
Most of the time you are right - people exaggerate horribly, misusing the wind chill notion. They're doing it again right now. I even heard one news reporter claim that because the wind chill had reached -40 F that car antifreeze wouldn't work any more. BS, the only thing that matters to physical effects is real air temperature. But, those two winters I spent in Minnesota I was very careful to sort that out and get the real air temperatures. Those two were century-scale record-setting cold and snowy winters.
That night it was so cold in Mankato, they were reporting 30 below all night, with 40 knot winds. It's true, too, I was there. You didn't leave town either. A couple of people who did, died that night. The corresponding wind chills were reported as -70 to -80 F. Actually, wind chill is almost meaningless once you're that cold. If you are not dressed for it, you're quickly dead. The numbers don't matter.
Those were real air temperatures that one morning, not wind chills. Point Barrow was reporting +32 F that very same morning it was -31 F in Mankato. There wasn't anybody in the Yukon reporting anything, but I'd bet it was actually warmer there that same day, as that's where the cold air mass came from. Before that air mass left the Yukon, I'd also bet it was pretty close to -100 F there.
GW
Looks to me like the wheels are the weak link. That's sad, because this thing is supposed to go off-roading into the rocky slopes of a mountain, not roll around in the soft sand. I have a really hard time believing this. But there it is, in the photo.
GW
Hi Bob:
There's nothing magic about the form factor of the Centaur tankage. The magic is the pressurized balloon approach, which is why it is as lightweight, and as cheap, as it is. Same idea could fit a variety of L/D form factors. It's just manufacturing tooling design. It would suffer long-term boiloff problems, but that's another issue.
There's nothing magic about the venerable old engine Centaur uses either. ULA has teamed up with XCOR to explore a lower-cost / same-performance LOX-LH2 engine. They just did their first subscale burn test a couple of weeks ago. The baseline design is 25,000 lbth, just like the "stock" engine, but expandable to 50,000 lbth. I believe it uses XCOR's piston-pump technology, not turbopumps.
So, I don't see why the basic Centaur stage design couldn't be adapted pretty readily into a lunar lander (or a Mercury lander, for that matter), with the potential to be very inexpensive, and very long-life reusable. Combined with an entry capsule, you have a reusable Mars lander pretty easily that way, too.
GW
Assuming nothing goes wrong, the only piece that reenters is the small return capsule. Having one with you enables an emergency free return if the engines both fail before arrival home. But there are two engines.
The propellant modules that come home arrive in LEO essentially empty. To be reused, they would need to be refueled on-orbit from some sort of tanker. The habitat would need to be restocked with supplies from some sort of freighter. Depending upon the nature of the engine design, they might not need refurbishment before re-use. At least, that's the kind of design I would recommend.
Point is, any ship capable of taking men to and from Mars orbit, can take men to near-Earth asteroids (asteroid defense missions), or to orbits about Venus and Mercury. Or it can return to Mars orbit. Why not build it just once to accomplish all those things as the time becomes right for each of them? A different lander would be needed at Mercury, but Venus and the asteroids need no landers at all. You will need more propellant modules, but so what?
GW
The manned vehicle in my chemical powered design was around 600 tons outbound, and a bit over 300 tons inbound to a recovery in LEO, not a free return. It was well under 200 m long, and spun at less than 4 rpm for 1 gee in the lowest deck, about 0.5 gee in the very upper (storage) deck.
Crew of 6, 3 reusable landers, 6 landings plus a Phobos visit, were the features in what amounts to a "cadillac" mission without actually going overboard into the "battlestar galactica" problem. That stuff is posted as "Mars Mission 2013" over at http://exrocketman.blogspot.com.
Sure, there are some not-absolutely-rigid dynamics issues to be resolved with a baton, but nothing anywhere as severe as a completely-nonrigid cable-connected design approach. Simple thrusters can spin it up and down. You put the hab spaces at one end, the engine cluster at the other, and a combined parallel-series stack of docked propellant modules in between.
Every module is small enough to launch with commercial rockets we have, except the landers, which have to be built-up in LEO from smaller components. They're just too fat to ride a Falcon-Heavy, although light enough.
GW
The image in post 1 above is called "frozen sea" or "pack ice", located in Elysium Planitia. If that is what it really is, ice frozen from a now-gone sea, it is likely freshwater ice. That is what happens in the polar regions here. The salty sea water freezes into ice at the surface, leaving the salt in the unfrozen sea water below. Excepting salt spray surface contamination, the ice is fresh water.
Personally, I think the next probe to Mars ought to land on one of those supposed blocks of ice. It should carry a drill capable of sampling 10's to 100's of meters down, plus examples of the ISRU and ISPP gear we are contemplating. Objective 1 - is that really the dirt-covered ice that it appears to be? Objective 2 - if ice, is it freshwater ice? Objective 3 - does any of our ISRU/ISPP gear really work on Mars? Objective 4 - what kinds of problems do we run into operating our ISRU/ISPP gear on Mars over extended periods of time?
It's just my opinion, of course, but not addressing these specific objectives at this oh-so-very-interesting site is another piece of prima facie evidence (among several lines of evidence) that NASA still yet has no intention of sending people to Mars.
One could make similar cases at other interesting sites, but I think this is one of the best. Any base or colony we intend to plant will need water. It's a whole lot easier to get from massive freshwater ice deposits than any other imaginable source on Mars.
GW
"I do not believe that desalination is that big of a deal" -- here on Earth that process is quite energy-intensive (because the process energy efficiencies are low) and the machinery is big and heavy and expensive. Most large plants now use permeable-membrane technology, for best efficiency and lowest operating costs, but face frequent very-expensive membrane replacements due to its high vulnerability to clogging. The smallest and most trouble-free machinery is also the least energy-efficient: the vacuum-flash distillation process used on ships for about a century now.
"Let's have a location that is close to dramatic scenery." -- actually I do agree with that, in so far as is practical. Part of keeping people sane is having interesting places to look at and explore.
GW
"Can you name a billionaire who got rich by picking someone's pocket?" -- how about the several "robber-baron" capitalists of 1860-1910? Might not be "billions", but equivalently-large sums when inflation-corrected. Another single example: tell me the big pharma corporations aren't doing exactly the same thing today, when drug prices in the US are factor-10 higher than in Canada, for exactly the same drugs made by the same companies, on the same production lines? Why? Because they can (money talks very loudly in government). Happens all the time. Has been happening for many, many centuries.
"The design that I was thinking of is simular to this image" -- a wheel station would have been the more useful one to build, although also harder to build. The one pictured appears to have a stationary docking core, requiring a moving joint. If you look at an on-axis enclosed docking bay instead, you need not use a joint. You just match spin to enter and dock, as in the movie 2001 "A Space Odyssey". That does require a larger design to make the gradients in the bay practically nil, but it also provides very low radial gradients out at the inhabited rim. Wheels make great space stations, but not such great ship designs: we need a lot more propellant mass and volume than we do inhabitable mass and volume.
GW
You can avoid all those difficult start-up dynamics difficulties if you go with a rigid (or at least semi-rigid) baton instead of a "loosey-goosey" cable-type connection. Shapes like that are really easy to build up from docked modules that current rockets can launch.
GW
For purposes of the kinds of discussions we are having here, engine efficiency is just the overall energy conversion efficiency: shaft power output divided by the heat release of the chemistry powering it. Your car is at the very best around 25% efficient by that measure, usually closer to 15%, assuming you drive around without rat-racing on paved roads, and that you don't pull heavy trailers, either. Off-road, around a third of those figures. Pull a heavy trailer, and you'll further cut those reduced efficiencies in half.
To figure fuel-oxidizer ratios, you have to balance the chemical equation (which does require knowledge of product species as an input). Quite often, you have to do this running fuel-rich. The coefficients are the molar proportions. The ratio of input oxidizer coefficient to input fuel coefficient is the molar oxygen to fuel ratio. If you multiply those balance coefficients by the corresponding molecular weights, the oxidizer-to-fuel ratio is then by-mass. The "r" you see in most rocket propellant combination data presentations is oxidizer-to-fuel ratio by mass. It's generally not stoichiometric, but fuel-rich, as I said. That's driven by where Isp maximizes, and that balance is chamber pressure-sensitive, which is why recommended r is a function of design chamber pressure.
GW
Hi Tom:
Actually I quite agree with you about inefficient government and about the example of the McMurdo base. The inefficient government that is indifferent to costs (except to be penny-wise and pound-foolish for political grandstanding) is exactly why I do not support an SLS done by NASA (it'll never be cheap to fly). As for McMurdo, Mars is much tougher to reach than Antarctica. The problem with McMurdo is that it's too easy to reach: you don't have to abandon it and go home. Any base NASA might establish and then abandon on Mars would be an inviting target for the likes of an Elon Musk. But only if there was some real prospecting done at that base while people were there.
I really do believe that, (1) if NASA ever does go to Mars (and currently they quite evidently do not want to, because none of the necessary things have been happening), and (2) if they actually establish a temporary base there (a really big if, because their entire orientation is toward flag-and-footprints stunts), they will abandon it, precisely because it would be too much expense to support a continuing presence there. There will be one, and only one government-funded mission to Mars, if any at all.
I fear that without a government exploratory mission, private interests will take a very long time indeed going to Mars on their own speculative dollar. Visionaries like Musk and Branson are rare, and would rather be paid to explore than fund it themselves. Exploration has little profit to it. That behavior has been true for centuries, even with visionaries, who are rare indeed. Most of the seriously-monied powerful interests are actually quite brain-dead, as far as progress goes. They got rich and powerful by cheating and picking others' pockets, not by actual speculative investing. Different from, but just as bad as, governments.
The problem is, that if there ever is a government-funded exploration trip, they most likely won't do it right. It'll be a stupid flag-and-footprints stunt, not real exploration. Which is what happened with Apollo on the moon. What we've learned about the moon has come from probes other than the landings, excepting for some few returns from the last 3 landings with the rover cars. But you don't learn a lot about buried resources just scratching around in the surface dust. No drill rig.
GW
Hi Quaoar:
To answer your questions, (1) I think a small-crew base could answer a lot of the adaptation questions in a lot less than 50 years. Although Tom disagrees, I don't think it would take a 100+ population to do most of that. But in practical reality, the adaptation base would slowly grow with time, anyway.
(2) I have come to think in recent months that we ought to start from orbit with smallish landers, and then also go to the surface and establish an adaptation base, all in that first mission. To do that smartly, with maximum probability of success, means that first mission ought to explore multiple sites to get real "ground truth" before establishing the the adaptation base at the "best" one. Multiple landings requires orbital staging (and a reusable one-stage lander), while you need to land everything and everybody at one site to establish a real base of any kind. So, do both in the one mission, as it is very, very, very unlikely in the extreme that a government agency of any nation, or even a consortium of government agencies, will ever fund more than one mission.
Tom disagrees with me, but I don't really believe the private entities will, in the next century or so, establish on Mars any sort of settlement, colony, or even just a base, until the necessary ground truth has been obtained by government(s) to let them plan their enterprise. That's just the nature of private companies, and it has been true for at least 500 years now. (The flip side is that there will be no continuity in the management of that adaptation base if a government mission actually plants one. They will operate it until it is time to come home, and then abandon it, all in the one mission.)
I doubt even Elon Musk will send anything to Mars until either (1) the government pays him to, or (2) the government has found a suitable site and verified ground truth about what resources are really there to use. Which government do I mean? Take your pick. Any or all of them. Doesn't matter. It was like that 500 years ago, too.
As for making ISRU/ISPP work at making propellants, yes I think so, but how good depends upon which one you are really talking about. I think using the Martian atmosphere to make LOX-LCH4 will work, as long as (1) you bring the hydrogen from Earth, or (2) you have an easy source of water at your landing site, and all the means necessary to extract it. I just think it will take years not weeks to accumulate tons of propellant, with any gear we can afford to take there.
If instead you want to use LOX-LH2, your site has to have lots of easy water, or your ISPP cannot work. But solar-powered electrolysis will generate hydrogen and oxygen faster, I think, as long as you can liquify them. Rapid liquifaction is the "long pole" in that tent. In part, because you must store immense volumes of uncompressed gases before running them through the liquifaction plants. "Plants" plural because the equipment to liquify hydrogen gas is quite different from the equipment to liquify oxygen.
Both propellant combinations ultimately require some amount of water. Until we have actual ground truth, we don't know where the water really is, how much there is, what quality it is, or how to transform that which does exist into a usable form. Remote sensing as it exists today cannot answer any of those crucial questions. Neither can zapping surface rocks with a laser, or scratching mere centimeters down with a sampler. You gotta drill 10's to 1000's of meters to find out for sure.
I think I get viewed as a pessimist because I really am an engineer versed in a lot of this stuff. Actually, I am an optimist. But I am also a realist. It's just that everything (in all aspects of life) is always more complicated, and takes longer, than any of us want.
GW
I know of what you speak, in spite of being a Texas flatlander. I spent two winters and a summer in southern Minnesota 1995-1997. Those were two record-setting winters for cold and snow, even by their standards. Real education for me. Feb 2, 1996 it was -31 F (-35 C) in Mankato where I was, -61 F (-52 C) at Embarrass, MN up near the Canadian border, and Winnipeg was reporting -85 F (-65 C). The afternoon high that day was -14 F (-26 C) in Mankato (same day in Dallas TX it was 97 F (36 C) with raging grass fires). I had a can of beer freeze solid that afternoon in less than 5 minutes, and not thaw for 3 hours after I took it back inside.
From New Year to mid-March 1996, it was always at least -20 F (-29 C) every morning, and never got above 0 F (-18 C) in the afternoons. Never had a place to plug in a block heater, so I just had to learn how to start a car dead cold-soaked. The next winter was about 10 F (5 C) warmer, but a whole lot snowier. 10 miles west of me, a man kept a 20-foot deep slit trench open all winter with his snowblower, just to get in and out of his house, on the second floor! His home was covered all winter by a 50-foot snowdrift. The snow that didn't melt came two days before Halloween, and we did not see the Earth again until mid-April. It all melted in 2 weeks and caused massive flooding.
All of that was an experience to remember, but not to repeat.
GW
Sounds like you are talking about using the lander as the manned transit vehicle. From a dead-head return propellant standpoint, Apollo showed it is better not to land the return vehicle (hardware and/or propellant). Just take down the minimum landing vehicle and surface stay supplies and equipment. I think the habitat required for a surface stay of weeks is different from the transit habitat for years in space.
From a radiation shielding standpoint, there is merit to your sideways cylinder geometry with the nuke in the middle. Depends upon the numbers whether the surface crew could stay in the vehicle cabin while on the surface. In the vertical geometry I looked at, they could not. How big a surface habitat is needed depends upon both crew size and length of stay. Different mission plans have different surface stay requirements of the landers. Cannot generalize.
GW
History says don't plant the colony on the first trip, if you expect it to succeed. It says do the exploration first to find out what all is there, and where exactly it is (and by implication, what quality the resources have). You can also plant a small base or station on that first trip to experiment with adaptation, if your during-the-trip results say things look good. If they don't, you'd better be exploring more than one site, or you won't get to plant that adaptation base. It takes real ground truth to answer the exploration questions. Remote sensing just doesn't hack it, not even today.
By adaptation, I mean using the resources you found to figure out ways and means to live off the land. That station may or may not stay populated permanently, but it is inherently manned by a small crew, since it has to be supported mostly (or entirely) by supplies shipped from Earth. It takes a lot of time in "adaptation" to figure out not just how to survive, but how to thrive. Once you have those answers, then it is time for mass quantities of colonists. It is inherently impossible to predict how long it will take to get those answers, even working at "best possible speed".
Actually, I quite agree with the notion that we could send up dozens of folks at once, right now. The 53 ton payload of Falcon Heavy would support such a manned transfer vehicle surface-to-LEO. But it is premature to send that many people to Mars (or even to the moon). A small crew needs to spend months-to-years figuring out how to make our ISRU/ISPP equipment really work well, and all the rest of adaptation, which goes far beyond our current concepts for ISRU/ISPP.
Even then, the problems of water, air, and propellants with ISRU/ISPP pale in comparison to the problems of growing food, mainly because we don't yet know how to build large pressurized buildings on Mars from local materials. Especially considering that (1) radiation protection at one level or another will be required of that vacuum-proof building, and, (2) its windows must let in the right portion of the light spectrum (some but not too much ultraviolet). We are just starting to develop designs for ISRU/ISPP. Nobody has any credible building designs yet. What are you going to use for concrete, for example? Some of these must be greenhouses, others residences. Not the same design at all.
And there are a whole plethora of infrastructure problems yet to be solved for any colony to thrive, not just survive. What kind of surface transport do you use? How do you build roads? How do you make steel? Aluminum? Plastics? Concrete? Etc? Some of us are talking about those things on this forum. But there are no credible designs or processes undergoing even early experimental trials yet. Just some laboratory benchtop stuff, and only for a very few of the many issues we have to resolve for a successful colony.
Nope, planting a colony is premature. We need to finish the exploration (started by robot probes), and start the adaptation process (which needs that surface base/experiment station).
GW