Large scale colonization ship

kbd512 · 2021-12-03 12:46:22

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RobertDyck · 2021-12-03 15:01:35

kbd512: I said a lot of things hadn't been added yet. I shouldn't have even given that figure. Mass is increasing dramatically very quickly.

Assumption for hull mass is stainless steel. I calculated mass per unit area for the Muliti-Purpose Logistics Module for ISS. That module was built by Italy and has a stainless steel hull. It's more than just a simple metal can, but using a real module for ISS as the basis means every layer of the hull is already included in this estimate.

And you gave a list of stainless steel alloys for cryogenic applications. I remind you, the hull of the ship is holding humans so the inside is shirt-sleeve temperature, not cryogenic. Using austenite alloys means it will not accumulate metal fatigue from temperature cycling, and you can weld it without having to anneal. That makes welding practical in space. Yes, outside surface of spacecraft do experience temperature swings from -250°F/+250°F (-150°C/+120°C); that's the extreme but you have to design for the extreme. Maraging steels... hmm...

The bunks that I describe are unique. I don't know any bunk beds that have both the under-mattress storage compartment of an American aircraft carrier bunk, and drawers like a "Captain's bed". And they should be made of composite materials to reduce mass, like furniture in a modern cruise ship cabin. Yet the storage compartment and drawers must be locked for the very reason you stated. Cabins can be locked so only crew and the passengers assigned to that room can enter, but still with multiple individuals in one cabin, storage must be locked. However, using standard size for single and queen size beds, we should be able to use COTS sheets. I reduced number of bed sizes so bedding would be standard. Laundry becomes simpler with fewer different sizes. So no twin, double/full, or king size beds.

You went into some detail about beds. I'm thinking of the dormitory at the University of Ottawa. In the June of 1979, when I was in grade 11, the social studies teacher took the entire class on a trip to Ottawa to see Parliament buildings. 3 day trip by passenger train, each way. University regular season ended at the end of April, so the teacher was able to book two floors of the University dorm. Beds there were "single" beds: 30 inches wide, with one mattress over a plywood platform, no box-spring. During my trips up north, one location the bed had one mattress on a wooden platform, but it was a thicker mattress and a "pillow top". With 38% gravity, I'm thinking a mattress like University of Ottawa dormitory would be enough. So that would be like an aircraft carrier "rack". As an adult I've gained weight, but again with 38% gravity it should be fine. When I was a young child, the sofa/chesterfield/couch in the living room was a hide-a-bed. That is, remove cushions to reveal a folded bed. The mattress was double bed size, folded double under the sofa seat, and part of the mattress was stored behind the back of the sofa. Once when a relative stayed over, I was asked to sleep on the hide-a-bed. It was quite comfortable. But when I had a girlfriend in the early 2000s, she had a small apartment with a hide-a-bed. I've gained so much weight that a support pipe under the mattress pushed into my back. The mattress of that bed is supported by steel strips that are held with coil springs. My weight pushed the mattress down too far. But again, 38% gravity; and hard platform (composite, not plywood).

I also said for standard cabins with economy furniture meaning bunk beds, the lower bunk could slide on rails. Obviously the bunk beside the washroom wouldn't. With two bunks beside each other, the lower bunks could slide on rails to the centre of the room. The rails would lock in place, just as car seat. You can adjust a car seat forward or back, but when you release the handle it locks in place. Single beds are 30" wide, queen is 60" wide, both the same length, so push two single bunks together makes a queen bed. Again, locking in place so they don't slide apart when sleeping is important. This means a family with two parents and 4 children, the parents could sleep together. It also means drawers must be able to open from either side of the bed. Sounds like a custom bed to me.

"Studio single" is also a standard cabin, just different furniture. Instead of bunk beds, it has a Murphy bed. One mattress on a composite platform, but an actual queen size mattress. When it folds into the wall, a table surface rises for use as a desk. The surface remains level as the bed is raised or lowered, so items on the desk/table surface do not spill off. No drawers under the desk/table surface, so the surface folds down onto the floor when the bed is down. This cabin would have wall units with drawers and cupboards.

I found a website of a company that manufactures all-composite cabins for cruise ships. That website includes mass of the cabin, including walls, furniture, washroom with all fixtures. Includes light fixtures, wall outlets and switches, toilet, sink, bathtub, plumbing & wiring, etc. I'm using that weight estimate for mass of cabins on my ship.

No free weights in the gym? Good idea! I came to that conclusion back in the 1990s. As I said at that time: "Can you say Blowflex?"

I was a computer software developer from 1981 through 2007, but since 2008 I've been a technician. I have a "standard technician's toolkit" in a backpack that I carry with me to every field service assignment. It's trimmed down, without my laptop computer it's 20 pounds. My laptop is now considered "old", with it's power adapter it's 9 pounds more. I have attachments for my smartphone that me use it for anything I would need a laptop. And that doesn't include specialty tools like cable pulling tools, soldering iron, small torx screwdrivers for Apple computer, suction cups to remove the glass front of an iMac, external DVD drive or floppy drive, USB adapter for hard drives (desktop and laptop), etc. My standard kit does include miniature suction cups for glass front of tablets or "Yoga" laptop computers. At a large company, the employer provides tools, but small companies expect technicians to bring their own. Where you use shared company tools, very often the tool you need goes "missing". Consequently experienced technicians bring a core set of their own tools, even when working for a large company. I'm expecting technicians going to Mars will want to bring their tools with them. Possibly recreational equipment, etc. You certainly won't be able to bring a moving van full of stuff for each passenger, but I expect more than just a "sea bag" per person.

Giving passengers jobs... Hmm... Some people don't like that idea. I had considered a small number of "junior crew" who get a discount by working as crew members. Standard crew would work the same long hours as cruise ship crew, but "junior crew" would have reduced hours. Yup, cruise ship crew work 7 days per week, 8 to almost 20 hours per day for the duration of the cruise: 2 to 11 months. I expect "junior crew" to have a discount on their ticket, but still have to pay for a ticket, and work 8 hours per day. But passengers could arrange something for entertainment: a professional scientist travelling to Mars could give regular lectures on his/her field. An astronomer could give a "tour of the sky", like a planetarium show, on the observation deck. No planetarium, instead you have the real sky. One year I was honoured to be asked to be the keynote speaker at the big annual event of the local chapter of the Royal Astronomical Society of Canada. It was held in a camping park a few hours drive outside the city. Truly dark sky. One individual gave a tour of the sky using nothing but a laser pointer. This guy was really good! I swear he was better than any show at the planetarium. I know the manager of the local planetarium; sorry, but it's true. The planetarium manager has been a member since he was a young child, and he was there too, so he knows.

Giving passengers actual crew jobs? Hm... those outside the military will find this strange. I had thought some people would want to learn how to do that. I had planned to include computer training programs for all shipboard jobs, starting from basics, so passengers could learn how to be crew members. Technical documents, everything required to operate, maintain, and repair the ship. As well as training programs for all sorts of skills people will need on Mars.

I don't want to get into gender roles. People fought against that in the 1960s. If a woman wants to do a job that some traditionalists consider a male role, or vice versa, then so be it. The only consideration is whether that individual can do the job.

I have planned emergency equipment. Each bulkhead will have a pressure tight door that can close the corridor. If a fist size meteoroid punches a hole in the hull, that pressure sub-compartment will seal shut. An alarm will sound, pressure tanks will try to maintain pressure for several seconds, giving passengers time to evacuate before doors automatically seal shut. A storage closet at the base of each spoke will store emergency equipment. This will include a soft airlock that can be sealed to the door frame of a pressure hatch. Anchors in the corridor walls will hold cords to hold the heavy plastic airlock open when all air has been pumped out. That same closet will include at least one pressure suit for use inside the spacecraft, so a trained crew member can enter the compromised compartment, rescue any passengers who remain inside.

RobertDyck · 2021-12-03 15:08:23

I'm using this ship as comparison. This is the SS City of New York. It's a steam ship used to transport passengers across the Atlantic before Charles Lindbergh flew the Spirit of St Louis. It's a transport ship, not a cruise ship. A lot fewer entertainment spaces, but there are some.

GW Johnson · 2021-12-03 16:05:57

RE my post 947 above: I went back and found the "exrocketman" article that examined Starship as a "lighter" to load/unload colonization ships in low Mars orbit. That was titled "Spacex Starship as a Ferry for Colonization Ships" dated 16 September 2019. Basically, the more you refill it, the more payload you can carry up and down, and the bigger your landing pad surface areas need to be. I showed over 200 metric tons payload with a full 1200 ton refill, but about 51 sq.m of landing pad surface was needed to support the Mars weight of the loaded vehicle, sitting on "soft fine sand" at 0.1 MPa safe bearing pressure.

I had also run a very generic colonization ship trade study for Mars and for Ceres, with different propulsion systems. That might have some bearing on what Rob is trying to do with his big ship design. My assumptions were propulsive departures from low Earth orbit and low Mars orbit, and propulsive arrivals in low Mars orbit and returning to low Earth orbit. That was "Colonization Ship Study" dated 9 September 2019. Regardless of the assumptions, if you look at the trends vs propulsion, you can easily see why I keep mentioning nuclear explosion propulsion. The ion drive would spend weeks to months in the Van Allen belts departing from Earth, and again upon returning to Earth. Not good for humans aboard.

Now, there are some metals with better hot strength than 300-series stainless steel. But they are not very good at cryogenic cold temperatures. If you have to do both, 304L stainless is about as good as it gets, and will have some weak strength at 1200 F, All these have just about the same strength at 1200 F, some can go hotter without scaling, but are weaker still at that hotter temperature. 316 and 347 are a couple of those. If you do not need the cold performance, 17-7PH will have 2 or 3 times the strength of 304L at 1200 F, and will go as high as 1400-1600 F, maybe even 1800 F with no strength left at all, depending upon how weak you can tolerate. But it is brittle as hell colder than about -65F. And I think it scales badly. Not sure how reusable that might be.

Titanium is NOT a heat-resistant metal, despite all the public beliefs, and all the hype. Its max recommended service temperature is the same as plain mild carbon steel: 700 to 800 F. The density is 0.174 pci vs steel's 0.283 pci, with more-or-less comparable tensile strengths at ambient. Aluminum is lower density still, at 0.10 pci, but has pretty much turned to butter structurally at around 350-400 F. If you don't believe me, then go look in Mil Handbook 5.

The main problem with titanium is that it is not formable. Not even the wrought forms. Try to bend it or stretch it, and it just cracks to pieces. Even the wrought sheet had better stay fairly flat, pretty much as supplied. You buy an ingot or casting, and literally carve away everything that does not look like your finished part. LOTS of waste during manufacturing.

But I am not a materials engineer by training or by trade. So go look in Mil Handbook 5 for yourself.

GW

kbd512 · 2021-12-03 17:47:54

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Calliban · 2021-12-03 18:08:25

This reference gives some interesting information on the strength of metals for high temperature steam plants.
https://www.imoa.info/molybdenum-uses/m … -steel.php

The strength of all steels falls off the edge of cliff at 450°C. The higher the room temperature strength of the steel, the greater the gradient of decline at that temperature. Adding molybdenum improves the situation slightly, but there isn't a great deal of benefit. Low alloy carbon steels lose half of their strength between 500 and 550°C. Nickel alloys such as inconel have much better temperature resistance. But they are expensive. Tungsten of course has excellent temperature resistance and is extremely strong. But it one of the densest metals and is extremely difficult to work.

Last edited by Calliban (2021-12-03 18:11:28)

RobertDyck · 2021-12-03 18:53:02

kbd512,
You're hitting on some of my hot buttons. University has 2 semesters per year, ostensibly 4 months each but in reality only 3 months of class time each. The rest is exams and vacation time. So university students typically study/work only 6 months per year. Most claim they have jobs during the summer, but cost of university is so high that they would be better off completing university early. Then they could get a good paying job. I had proposed a local provincial version of advanced placement high school so students graduate with full credit for first year university. That way the just skip first year university. Then schedule exams to fit within a single week. There are typically 5 courses per semester, a 3-hour exam for each course, so 15 hours of exams. You should be able to schedule that within a single week. Reduce Christmas vacation to one week, keep spring break (one week), start classes the beginning of September on the same day as high school, and have classes run to the end of June (like grade school). That's 10 months, but with 3 semesters with 3 months class time per semester, so 9 months of class time. It includes 1 week of exams at the end of each semester, one week vacation for Christmas and one week vacation for spring break. Currently 2nd, 3rd, and 4th year are 2 semesters each for a total of 6 semesters. With what I proposed it's 3 semesters per year, so those 6 semesters are completed in 2 years. That does not reduce class time by even a minute, nor does it reduce lab time nor assignment time. It only reduces vacation time. Combine that with advanced placement, and a 4-year bachelor degree is completed in 2 years. Charge the same annual tuition as today, and it means total cost of a bachelor degree is cut in half. I convinced the provincial Minister of Education to do this. Administration for the University of Manitoba got him fired and kicked out of cabinet. All initiatives he started were undone.

So yea, rich people who consider themselves "elite" do take half a year off. I also met a lot of civil servants who do very little at work, and refuse do anything during the summer. They want to go to a cottage and sit on a dock drinking beer or their favourite cocktail.

Dr. Shannon Rupert has run MDRS since it was built. She complained that many crew tried to treat it as a hotel, and expected maid service to clean up after them. She had a massive problem of equipment not properly maintained, and the facility left untidy, not clean. She pointed out real astronauts have to do the work, no one will do it for you. But scientists who spent 2 weeks at a time at MDRS did not understand that. she ended up moving into MDRS permanently. She now has a loft under the dome of the hab, above the bedrooms for crew. She tries to remain unseen during simulations, but she's there to ensure people do their work.

As for male vs female: certain jobs require strength, but most jobs today do not. Decades ago the US air force did a study of female fighter pilots. Their lower centre of gravity meant they should be able to withstand high G manoeuvres better. Lower body weight is also an advantage, so the aircraft can carry that much more ammunition/ordinance. They found female fighter pilots did work just as well as the men. However, some guys who viewed that job as a "man's job" didn't like the result.

During World War 2, all able bodied men were conscripted (drafted) into the military. That left too few left to do necessary support jobs like manufacturing ammunition, etc. Women were recruited. But women didn't have the upper body strength necessary to unload heavy truck loads of cargo. So they developed wooden pallets and a device called a pallet jack. Forklift trucks were also invented. With that, a woman could move more cargo at one time than even the strongest man.

Yup, I've seen female plumbers, truck drivers, engineers. Yes, I would argue standards should not be lowered for female police or fire fighters. I met a female police lieutenant who know what she was doing when all the men were either standing around doing nothing, or actively doing things wrong. There are some jobs that more men do than women, but I wouldn't assign gender roles, I would let anyone qualified do it.

SpaceNut · 2021-12-03 18:58:55

The cleanliness and organization problem goes across more than the work being done at a research station as I have seen it even where I work. Its part of its not my job to act grown up and take care of my things; its not part of what I was hired for (insert unionized worker blinders here) job description...

kbd512 · 2021-12-03 21:00:18

Robert,

Most people who would go to Mars are not independently wealthy, especially after they just spent every last cent they had to buy a ticket to go there. Therefore, they need jobs. The majority of people who are independently wealthy won't be going to Mars, because there's no tangible benefit to doing so. There are no Gucci or Luis Vuitton stores on Mars. Moreover, we don't really want people who are unwilling to do real physical work. Those would be the same freeloaders who want to live in adult playpens, protected from all consequences of bad decision making. Trust me when I say you don't want such people anywhere near where you live.

I happen agree with Dr Rupert's assessment of people looking for an all-expenses-paid vacation, rather than a job that requires real work to be done, and her admonishment regarding the importance of minding the store. One of the first things you learn in the military, is that your mommy and daddy don't live there with you. It's your job to clean up after yourself. That's simply part of being an adult. People who don't clean up after themselves are either not adults or they're physically disabled. Since we're sending able-bodied adults to Mars, that means they need to clean up after themselves.

Most jobs that a highly technologically advanced civilization requires, that you're personally interested in doing, may not require physical strength, but I you've also never worked aboard a ship before and I'm guessing you've not done much construction work, either.

Since I was actually in an aviation squadron that operated from USS Carl Vinson and USS John C. Stennis, I really don't care about what your US Air Force study shows. Pilots represent around 1/100th of the jobs in the US military, despite the number of aircraft we have. If we made 100% of all fighter pilots women, which I'm not at all opposed to if they're truly the best for the job, then we could save around 100 pounds per crew member, maximum. That 100lbs represents 40 seconds of extra flight time, 1 Hellfire missile, 1 .50 cal and mount with no ammo, 166 rounds of 20mmx102mm ammo, 1/2 of a Sidewinder or SDB, or 1/5 of the smallest JDAM we use. In other words, an utterly meaningless amount of weight relative to the 29,320lbs empty weight of the F-35A. We could save 2,000 pounds of weight in each F-35 by switching to CNT wiring, if we were that concerned about weight. +/-100lbs in a fighter jet of that size has zero practical effect on its operational capabilities. In the micro fighter concept I proposed, 100lbs would be a lot- and yes, I would primarily be recruiting women to fill those ejection seats, out of necessity. That said, nearly all of the fighter pilots I've seen, men or women, weigh between 150lbs and 220lbs. They walk out to the jet with 30lbs to 40lbs of gear on. I've seen some petite female helo pilots, but vanishingly few petite fighter pilot for that reason. No matter how big or small you are, you climb aboard the jet wearing that gear. Flight time is only around 250 hours per jet pilot per year, 400 tops even with combat, which leaves the other 8,510 hours spent on the ground, lifting and moving heavy crap in extreme heat and cold. That requires strength only granted by sufficient muscle weight.

People who are short and stocky withstand high-G maneuvers best, but it's mostly about wearing a properly-fitted G-suit, proper technique, proper hydration, and adequate rest. Tall lanky people don't do as well. People who are dehydrated fare far worse than anyone who is properly hydrated.

In our squadron, we packed up and moved by hand absolutely everything we owned that wasn't self powered (our jets), every 2 weeks to 6 months. That requires a lot of upper body strength, so the women in our squadron packed things up and then, for the most part the men moved those heavy steel boxes. The smart women who attempted to move those boat anchors quickly realized that the boxes weighed as much as or more than some of them did, and then politely asked for help, which was provided without comment or complaint. After observing the results first hand, you begin to see the absurdity of the notion that men and women are equal in all things. They are not, and all blather to the contrary is just noise being made by people who have never once done what they're asserting is so easy to do. Everyone talks a good game until the rubber meets the road, and then harsh physical reality takes over.

This sort of commentary reminds me of my own son's assertion that, "he already knew all there was to know about driving" (yes, he actually said that to me before he was even done with driving school), whereupon not even 2 seconds later he promptly ran my Impala into the curb of the Lowes parking lot I took him to so that he could practice driving, then got upset because I yelled at him. For reasons only he could tell you about, he mistakenly thought I cared more about the car than him. My admonishment to him was merely, "Son, forget about the stupid car, I don't care about the damn car, WE'RE IN THE CAR!" I yelled at him to bring attention to the most salient point of fact that was top of my mind while he was learning to drive- his life is in real immediate danger while driving, and watching a video in a classroom is not equivalent to the experience required to drive a powerful and heavy motor vehicle in close proximity to immovable objects and other motor vehicles. That's classic Dunning-Kruger, as is the rest of this silliness about fighter pilots and flying.

All that said, these young people are going to another planet to build another branch of human civilization from scratch. There will be manual labor galore and a dearth of machines to make that labor simpler and easier to do. That's primarily construction work involving hard and dangerous manual labor. There will be no continuation of humanity without more people living on Mars, which means creating and raising children to carry on, and hopefully, to do a better job than we have done. Only women can create more people, so they're just as essential to the task as any construction worker. To that end, the nuclear family is the bedrock upon which all high-functioning human civilizations are built.

RobertDyck · 2021-12-03 23:06:54

kbd512:
I've lived on my own since I was 22. I cleaned my own apartment. I've owned this house since 1990, and clean it myself. I do my own laundry. I'm sure the military would not like how I keep my house, but to anyone who doesn't like my housekeeping, just stay out of my house. I've repaired my own furnace, twice. I did hire a repair technician to repair my clothes dryer. Actually, I learned what he did and used principles for the second repair of my furnace. I also had to ask assistance from a couple friends to replace my water heater. Don't try to lecture me about taking care of stuff.

I did a little construction work. I suspect you haven't. When I was just 8 years old, my father built a detached double garage for our house. I was interested and watched. The whole family participated in shingling the roof. My father built scaffolding around the garage, we all pitched in. Our neighbour then hired my Dad to build a double garage just like it. I helped. My father built a bedroom for my brother and myself in the basement, and I helped with that. I learned framing, drywall, hanging ceiling tiles, electrical. As a teenager, my father had my brother and I build a couple more garages, including the one for his house after my parent's divorce. I poured the trowelled the concrete sidewalk from the house to the garage myself. My father claimed I would make mistakes, so I made a point of not. Decades later the sidewalk had shifted, so he had to lift the blocks to re-level them. He said he thought I had poured it as 3 separate blocks. I told him it was one single pour, but I trowelled edges and separation lines so it looked like three blocks. And if the ground heaved (as frozen ground does in winter) then the sidewalk would split at the lines I had trowelled in. It worked so well that even after my father lifted the blocks, he still thought they were separate blocks.

I saw a documentary on TV about Canadian fighter pilots. The show focused on a Canadian fighter pilot, flying a CF-18. Yes, that's the same as a Navy F/A-18C Hornet but with Canadian colours and the dashboard calibrated in metric. Not many women choose to do it, but those who do are just as good. By the way, I found it interesting she was concerned with impressing the "boys" so she could get a date. Just the same as male fighter pilots trying to impress girls on the ground. Same same.

However, we need to stop talking about military. You keep bringing back military stuff. In civilian life, men don't have significant strength beyond that of women. Expect a typical non-military man to lift a 100 pound box? Not going to happen. I've applied for warehouse jobs where applicants had to lift 50 pounds. The fact that I can lift 100 pounds, as long as it's not often, is something that health and safety has concerns about. You're supposed to get a forklift or powered pallet jack to lift something that heavy.

This reminds me of a scene from the TV show M*A*S*H. A truck had somehow turned onto it's side. The doctors tried but the truck wouldn't budge even a tiny but. Even with as may doctors and orderlies as they could line up along the length of the truck, it didn't budge. Then a jeep with marines showed up. Just 4 marines pushed the truck easily as if it was a toy, pushed the truck upright onto its wheels. Different people do different things, but if you think all men could do that... no. The surgeons could right a truck, but they can save the life of a wounded soldier. Different skills. If there's a woman who wants to be a soldier like Vasquez from the movie Aliens, then more power to her.

kbd512 · 2021-12-04 02:06:47

Robert,

I already told you what living aboard a ship involves. It's hard physical labor, plain and simple. There is not infinite space or weight to have every conceivable piece of machinery to move heavy cargo around, and there certainly won't be aboard an interplanetary transport. Moving heavy cargo around is a good reason for having all those strong young men aboard.

Immediately after telling me that I need to stop talking about the military and asserting that there's no need for civilians to lift 100 pounds, you then tell me that you can lift 100 pound boxes and have worked in a warehouse filled with 100 pound boxes. This bizarre argument is over, by your own admission of basic reality- that manual labor frequently involves moving lots of heavy stuff around, and that you can easily do it, despite never having spent a day in the military.

Do I ever tell you that you need to stop talking about being a civilian? If not, then perhaps you could return the favor.

RobertDyck · 2021-12-04 09:24:37

kbd512: you said what it's like to work for the NAVY onboard a ship. Perhaps I wasn't assertive enough. My mother absolutely hated the military, whenever I expressed interested in military technology she had a panic attack. But the military is about killing people, it isn't about building anything. War is mass murder. Wars have *NEVER* been fought for any principle, they're always about money and power. Before World War 1, wars were profitable. Enemy nation would be sacked and looted to not only pay for the war, but ensure profit for victor. Many have demonized Nazi Germany for looting their enemies: taking art, gold, etc. But that has been done since prehistoric times through all wars before WW1. Looting is no longer accepted by western nations, and that's the primary reason war is so rare in Europe. Before prehistory European nations have used war to land and resources from other nations. That means war is armed robbery, mass murdering anyone who attempts to defend themselves. Even World War 1 was about resources: Russia and the Austro-Hungarian empire wanted a sea port in the Mediterranean. They competed for influence over Bosnia and Herzegovina. Assassination of Archduke Franz Ferdinand quickly escalated and both dragged in their allies.

I can't stop talking about being a civilian, because civilians *ARE* the nation. Civilians build everything. The military is a drain on resources. Sacking your enemy to make war profitable is really nothing but armed robbery, it's criminal and cannot be justified. Result is massive destruction of everything. Are you familiar with the Bronze Age Collapse? Other than that, military drains resources. Civilians build everything.

tahanson43206 · 2021-12-04 10:22:04

For RobertDyck .... it seems to me the common denominator for ** all ** wars is testosterone, although a ** few ** may be driven by desperation to feed the population of a region.

I have often thought that if Hitler had simply undertaken to charm the world with the quality of German made products, we would all be speaking German and much better off.

China's Chairman Xi is (apparently) doing something similar to that ... he seems to be pursuing an economic charm offensive in regions on his borders, having entirely sucked up the manufacturing capability of the Americans.

This topic is about Large Ship .... the immediate debate topic was gender roles aboard Large Ship. I suspect that by the time that ship is flying, women will have quietly assumed all significant roles in managing the vessel and keeping men busy wrestling and other amusements.

(th)

SpaceNut · 2021-12-04 10:23:15

Sort of true but there are branches of it that target rebuilding and that is the structure that we are looking to bring forward. Its the logistics and more which is what makes it capable as its a can do attitude.
ex was the seabee's of the Navy
https://www.navy.mil/Press-Office/News- … es-on-nav/

back to topic

We launch the pieces to construct the ship to orbit and use it to now transport to mars and it seems that we are now looking at landing it on mars if I get the post.

GW Johnson · 2021-12-04 10:50:41

I may be wrong, but I think what Rob has in mind for the large ship is an orbit-to-orbit transport that never lands anywhere. It is serviced in low orbit at both ends of the journey by small ferry vessels capable flying up to orbit and back. On Mars that can be single stage, using aerobraking to return to the surface, with propulsive touchdown. On Earth, that is necessarily a two-stage vehicle, also using aerobraking to return to the surface, and very likely using either wings or propulsion to touch down.

This transport that never lands is instead serviced by ferry vehicles, analogous to the scheme used with ships for centuries before we were capable of building deep-water harbors. The transoceanic ship would anchor offshore. It would be loaded and unloaded by smaller boats termed "lighters" that had drafts shallow enough to reach the shore more effectively. It's a well-proven strategy, and it worked very well for centuries.

It applies directly to the concepts being debated here, and does not depend in any way upon the propulsion selected for the large ship. Although, if the large ship used propellants that could be made on Mars, then the two-way journey becomes feasible, with the better forms of chemical propulsion. Some sort of nuclear just looks even better.

But unless you have really effective radiation shielding built into your large ship, good enough to conn it through maneuvers while immersed in the Van Allen belts, then you can forget about electric propulsion while departing or arriving at Earth. The transit times through the Van Allen belts are too long; that must be done rather quickly with people. Mars does not present that severe radiation exposure problem, since it has no radiation belts. You can use electric propulsion there; it will just cost you spiral-in/spiral-out time.

GW

kbd512 · 2021-12-04 11:22:50

Robert,

Navy ships are still ships. They still require supplies and equipment, like any other ships. They're still crewed by sailors, like any other ships. The crew still has a duty to their ship and to each other, like any other ships. So long as civilian ships are similarly space and weight constrained, then the same basic operating principles still apply equally to their ships. I assert that interplanetary transports are far more space and weight constrained than any ocean-going ship, of whatever description, ever has been or will be.

Our military is controlled by civilian authority. We do not act without their explicit approval. We were ordered to kill people deemed to be our enemies by your fellow civilians. We take an oath to obey their commands, no matter what we personally think of such orders or the people giving them. What we did was done with a keen eye to protecting innocent life while defeating our enemies. All loss of innocent life is regrettable, but all of it occurred carrying out the orders of civilian authorities. Your reductive assertion that "civilians build everything" very conveniently ignores the fact that civilians are also behind nearly every act of war in modern times.

From interacting with someone who once fancied politics, and now wants to be a dictator to everyone living on another planet, it's pretty clear that excessive pride in self / ego is a significant contributing factor regarding why we have so many pointless wars. A bit of self-examination could do wonders, but that would require real work rather than finger pointing.

kbd512 · 2021-12-04 11:41:43

GW,

An article from the International Journal of Astrophysics and Space Science:

Radiation Analysis for Moon and Mars Missions

An article from NASA on the Van Allen belt radiation levels (very simplistic):

The Deadly Van Allen Belts?

And another from NASA (very simplistic):

The Van Allen Probes and Radiation Dose

I think passive shielding would be sufficient to adequately protect the crew, since this ship will have considerably more shielding than capsules or ISS modules.

Edit (I like this one because of how the dose rate is modeled for a 1m sphere using various shielding materials):

Analysis of the passage of a spacecraft between the Van Allen belts considering a low and high solar activity

Edit #2:

OPTIMIZATION OF LOW THRUST TRANSFER ORBITS OF A SPACECRAFT CONSIDERING THE RADIATION HAZARD FROM THE VAN ALLEN BELTS

Last edited by kbd512 (2021-12-04 14:00:06)

RobertDyck · 2021-12-05 04:44:02

The saucer landing sequence from post #964 is from the movie "Star Trek Generations". The blue bar labelled "saucer module separation systems" is the LCARS interface, a fictional graphical user interface used in Star Trek TNG/DS9/Voyager. The ship Enterprise D was supposedly built in orbit of Mars, supported by a facility on the surface at Utopia Planetia. That ship was not supposed to land either, but the engine section exploded. The saucer section separated before the explosion, but was hit by the blast wave and pushed into the planet's atmosphere. The landing was a crash, lower decks were crushed, and the ship would never fly again. But again, that's fiction, we're attempting to design a ship that could actually be built.
tumblr_mvzk7qQARq1rzu2xzo4_r1_400.gifv tumblr_mvzk7qQARq1rzu2xzo5_r2_400.gifv tumblr_mvzk7qQARq1rzu2xzo8_r1_400.gifv

RobertDyck · 2021-12-05 20:49:25

Reminder of an old image. I had envisioned pressure tight compartments for standard cabins like this...
kFu65wI.jpg?1

RobertDyck · 2021-12-05 21:43:23

Talking to kbd512, he raised electric propulsion. In year 2000 I sent an email to the Russia rocket corporation Energia. They responded in February 2001... in Russian. I got it translated.
Page 1, Page 2

RobertDyck · 2021-12-05 22:22:59

Link to calculation of sunlight collector area required for oxygen generator: Post #898

RobertDyck · 2021-12-05 23:06:58

ISS Cupola construction

Another reference: (click image for source)

RobertDyck · 2021-12-05 23:52:22

We need to get cabin mass, so I can calculate ship mass reasonably. I used mass of an all composite cabin for cruise ships. The standard cabin for our ship will be more compact. How do we estimate cabin mass?
LiteCab™ Lightweight Composite Cruise Ship Cabins

kbd512 · 2021-12-06 11:51:22

Post moved to another thread.

Last edited by kbd512 (2021-12-21 09:24:15)

Calliban · 2021-12-06 12:28:20

You could use a stainless hull of reduced thickness by attaching bracing cables between points on the hull and a central shaft. The cables could be carbon fibre and would be prestressed to partially balance the forces imposed by internal pressure and rotation. Redundancy could be built into this system, which would allow cables to be replaced individually once they surpass a precalculated fatigue life. All of this is done inside of the ship, so no spacesuits are needed.

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#951 2021-12-03 12:46:22

Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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Re: Large scale colonization ship

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