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#601 2021-01-20 02:45:47

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
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Re: Large scale colonization ship

We should probably have a nutritionist on the team. Here's one suggestion. First, no iceberg lettuce. I've heard from nutritionists that it basically just holds salad dressing, lots of fibre but no nutrition.
Inspiration: How to Make an at Home Salad Bar

  • romaine lettuce

  • raw spinach

  • cherry tomatoes

  • sliced bell peppers (green & red)

  • sliced cucumber

  • grated carrots

  • snap peas (stringless)

  • green beans

  • strawberry

  • green onion

  • bean sprouts

  • broccoli

Croutons can be made from bread baked on the ship from flour brought from Mars.
Some canned, dried, frozen or refrigerated food brought from Mars:

  • black olives

  • onions - spanish, red

  • chickpeas

  • black beans

  • kidney beans

  • dried cranberries

  • raisins

  • sesame seeds

  • sun-dried tomatoes (Well, greenhouse dried, with a fan?)

Trees will take some time to establish in greenhouses on Mars. Once established, we could add: sliced almonds, dehydrated apple slices, pistachios, pecans.

16 Vegan salad dressing recipes
Trying to avoid dressing with mayonnaise or dairy.

  • Catalina

  • Lemon poppy seed

  • Cherry tomato

  • Maple mustard

  • Greek

  • Olive oil

  • Balsamic vinegar

If we grow agave on Mars, we could add Carrot Ginger, Tangy Miso, and Balsamic Vinaigrette dressing.
Artificial maple extract can be made with vanilla extract, fenugreek seeds, and vodka. Vanilla extract with real vanilla bean and vodka. Maple syrup with artificial maple extract, brown or yellow sugar, and hot water. The extracts and sugar brought from Mars.

Mushrooms can be grown in compost. White mushrooms require growth medium with high nitrogen; most websites recommend a 50:50 mix of compost with horse manure. The mushroom farm a couple km from my house uses composted chicken manure. When the wind blows the wrong way... Shall we say not on the ship? Button mushrooms are another name for white mushrooms. Portobello mushrooms are white mushrooms simply allowed to grow to maturity. Cremini/crimini is actually also the same species. However, Oyster mushrooms grow on straw, sawdust, coffee grounds, other agricultural waste; we could grow them.

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#602 2021-01-20 07:56:27

tahanson43206
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Registered: 2018-04-27
Posts: 16,756

Re: Large scale colonization ship

For RobertDyck re #601 [Nice!]

SearchTerm:Nutrition Call for nutritionist for Large Ship planning http://newmars.com/forums/viewtopic.php … 48#p176048
SearchTerm:Nutritionist

(th)

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#603 2021-01-20 13:08:34

tahanson43206
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Registered: 2018-04-27
Posts: 16,756

Re: Large scale colonization ship

The presentation at the web site below may be of interest to those who are planning cuisine for the Large Ship.

The company came to my attention via the North Houston chapter of the National Space Society.

One of the officers of the company made a presentation which is reported in the Other Space Advocacy Organizations index.

Spira Inc. <info@spirainc.com>

Replacing dye, one dash of Electric Sky at a time
At Spira we’re specialists at helping you incorporate algae-based ingredients in your everyday products.

As scientists, dreamers and creators, we are always experimenting with our products and making everything from cookies and ice cream to smoothies and cocktails. Our community has also created some incredible products that we have been “dye-ing” to share with you. This new time at home has allowed many of you the freedom to experiment, and we want to highlight your work.

Over the next few weeks, we’ll be updating you with recipes and best practices so you can incorporate Electric Sky™ into your everyday life.

(th)

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#604 2021-01-20 18:12:29

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Large scale colonization ship

The company was posted about before and while I did not spot it here in This topic  I am sure with time I can find it....

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#605 2021-01-20 18:36:38

tahanson43206
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Posts: 16,756

Re: Large scale colonization ship

For SpaceNut .... here is a link to the original announcement of the presentation to the North Houston chapter of the National Space Society:

(th)

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#606 2021-01-20 20:21:39

RobertDyck
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From: Winnipeg, Canada
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Posts: 7,782
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Re: Large scale colonization ship

Found a paper on how much people consume from a salad bar. The focus is on influencing people to change their eating habits; not something I agree with. But the useful thing is actual numbers showing how much people eat. In grams per person per day. here

               #1        #2        #3        #4      Average
Broccoli     5.5,6.9      -      5.0,5.3      -        5.675
Cucumbers   12.5,16.9 16.6,17.8     -         -       15.95
Mushrooms    7.8,9.2      -      5.9,6.4      -        7.325
Olives       7.4,9.3      -         -         -        8.35
Tomatoes    17.5,19.0     -     12.2,12.9 14.8,16.4   15.4667
Bell Peppers    -     12.3,11.4     -         -       11.85
Carrots         -         -      7.5,8.1      -        7.8

So now how much greenhouse space for each food for 1,200 passengers?

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#607 2021-01-20 20:53:46

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Large scale colonization ship

Well with some form of dried pasta you can also have a tomatoes sauce that will be quite favorable from many of the same ingrediencies.

The meal planning to use the growth pattern is key to nutrition so as to not have salad everyday....

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#608 2021-01-21 01:51:26

RobertDyck
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From: Winnipeg, Canada
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Re: Large scale colonization ship

I watched the video you linked: Spira. I was a preschooler in the 1960s, the space race was underway. There was a comic book called "Major Matt Mason" about an astronaut living in a permanent base on the Moon. They grew algae, prepared as firm disks called algae cakes. In the comic book they had the flavour of cardboard. So this isn't a new idea. A science fiction book talked about growing algae for food, using human waste (feces & urine) as fertilizer. The problem is algae has to grow *IN* the fertilizer. So if your source of nutrients is shit, then your algae cakes will be a mixture of algae and shit. The Green CELSS Task Force was a group in the early days of the Mars Society that chose to compost human feces as fertilizer for more traditional crops. Green Hab was another group, using a grey water sewage processing system to process feces and urine to become nutrients for a greenhouse. The problem with all of these is processing of human waste to become suitable fertilizer, without contaminating the food. Yes, a composting toilet or grey water system is ideal for Mars. But a spacecraft requires something very compact. Even the large ship requires a compact system, and nutrients must be recycled quickly, not over years.

Here are some issues with fertilizing with human urine. I suggested filtering urine to extract water. The reason is to recycle as much water as possible. So I envision the same system NASA uses on ISS. Or more precisely, after NASA fixes it so it doesn't get clogged with calcium deposits. The process of filtration should remove pathogens. And a lot of urine won't be used as fertilizer; it'll be stored along with dried feces as nutrient delivered to Mars. Here's one website that talks about using your own urine as fertilizer. They recommend not eating food for a month after fertilizing with urine. My solution was to use composted urine only for crops with produce above the fertilizer: peas, beans, strawberries, but not root crops like carrots. The only fertilizer for root crops will be fish poop from tilapia tanks. That's aquaponics. This ensures food is not contaminated.
Fertilizing with human urine

Human urine contains a lot of salt, so has to be diluted. Human urine is extremely high in nitrogen, mostly as urea which is two molecules of ammonia bonded together. There's also some creatine. Composting with carbon matter causes aerobic bacteria to convert it into nitrates. Wikipedia says human urine is low in phosphorus and moderate potassium.

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#609 2021-01-21 07:45:26

tahanson43206
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Re: Large scale colonization ship

For RobertDyck re #608

Thanks for taking a look at the Spira presentation.  Do you want to follow up with the company?

Would they be interested in your project?  As nearly as I can tell they are primarily focused upon finding markets for their products on Earth.

***
Thanks for the compact review of issues for recycling materials in the Large Ship and on Mars.

On Earth the system is large enough great numbers of us have the luxury of not worrying about the processes that allow us to keep living in comfort and safety. However, even on Earth, and certainly in advanced nations, great numbers of folks are on duty every day designing, building and operating facilities to clean waste products for re-use by plants, animals and humans.

Nature still carries the greater part of the burden, but the increasing numbers of humans on the planet inevitably means humans must take greater and greater responsibility for managing the flows of waste back to re-use.

On the Large Ship, and on Mars, 100% of the responsibility will be borne by humans.  Your post is a concise reminder of what is involved.

(th)

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#610 2021-01-21 16:53:55

RobertDyck
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From: Winnipeg, Canada
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Re: Large scale colonization ship

tahanson43206 wrote:

Nature still carries the greater part of the burden, but the increasing numbers of humans on the planet inevitably means humans must take greater and greater responsibility for managing the flows of waste back to re-use.

In elementary school in the early 1970s, we had a field trip to the city sewage processing facility. At that time it started with a large tank the size of an Olympic swimming pool, with fixed steel rakes across the surface. Water flowed from one end to the other; it removed toilet paper. Then several smaller round settling tanks. One tank filled then left still to allow feces to settle to the bottom. Round so a rotating arm could scrape solids off the bottom. Feces were put in large stainless steel tanks in a heated building; called digesters they used bacteria. The result was called night soil. It was spread on farm fields that only grow fodder - animal feed.

Our province has a number of hog barns. Government regulations require every hog barns to have contracts in place with farms to receive hog manure. They're only allowed to spread a certain maximum per acre, because more will not soak into soil, rain will wash it off into drainage ditches.

The point is food is never fertilized with manure from the same species that eats it. That helps control disease.

And if you're interested in the whole system, liquid from the setting tank has oxygen bubbled through. The sewage treatment plant has a large facility to filter oxygen out of air. Oxygen catalyzes a reaction of urea with water to become oxygen and ammonium. Yea, the reaction needs excess oxygen, but produces one O2 molecule per urea molecule. Then ammonium reacts with oxygen to become water and nitrogen. It doesn't go to completion, but most urea is disposed of this way. That leaves salt, potassium and phosphate. Another tank grows algae to consume those. I think they have a new phosphate removal system now, but that's what they did then.

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#611 2021-01-24 09:06:57

tahanson43206
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Posts: 16,756

Re: Large scale colonization ship

For RobertDyck re #610

Thank you for the helpful review of waste processing in a large community on Earth!

SearchTerm:Waste processing on Earth for a large community - RobertDyck - http://newmars.com/forums/viewtopic.php … 96#p176096

From time to time I will try to renew the (currently missing) Critical Path item of stability of the Large Ship design, and Practical Navigation of the same.

I ** really ** like the idea first proposed in the opening of this topic, to rotate the entire vessel and to do with out bearings.

The matter of practicality of this design is left unanswered.  It ** can ** be answered by placing an experiment in space.  That could be done with a package delivered to the ISS, or it could be done using one of the (now many) smaller launcher companies. 

The experiment would establish:

1) How to compensate for perturbations caused by movement of mass inside the moving (rotating and moving) vessel
2) How to accelerate the vessel toward Mars from Earth from Low Earth Orbit
3) How to decelerate the vessel at Mars

In thinking about this problem in recent weeks, I've pondered the possibility that the vessel could be accelerated along the axis of rotation at appropriate times in the orbit around Earth.  It was given as a principle early in the setup for this topic, that the axis of rotation of the vessel would point through the center of the Sun.  In that case, and if that orientation is maintained throughout the service live of the vessel, then the thrust applied to move the vessel away from Earth might be timed to coincide with the needed alignment with the destination near Mars.

I've also come to the realization that it is completely unnecessary to slow the vessel at Mars.  If the planners think along the lines of Aldrin's Cycler, then the vessel itself could provide the comfortable accommodations for Starship passengers for the trip to Mars, while the Starships themselves tag along like support ships around an aircraft carrier.  At Mars, the passengers and crew would return to the Starships, where they would perform the maneuvers for which the Starships were designed.  Meanwhile, the Starship would coast along it's planned trajectory, to return to Earth after a two year flight.

GW Johnson posted details about such a two year flight plan earlier in the forum.

If the Large Ship Franchise planners adopt this scenario, then the ships themselves will have a chance of surviving for many decades, and even perhaps for centuries with appropriate refurbishment.

Assuming that it is desirable to slow the ship upon it's return to Earth (unlike the Aldrin Cycler which did NOT slow) then (perhaps) the same technique can be used in reverse, if there is a moment when the alignment of the axis of rotation matches the needed vector for a thrust to place the ship safely back in LEO.

The services of someone (or a team) well versed in celestial mechanics, and with the appropriate computing tools, would  be welcome.

If such a person happens to see this post, you can communicate with RobertDyck through the Recruiting Portal at NewMarsMember * gmail.com.

(th)

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#612 2021-01-25 02:06:15

RobertDyck
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From: Winnipeg, Canada
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Posts: 7,782
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Re: Large scale colonization ship

Let's look at crew again.

Housekeeping:
Canadian Centre for Occupational Health and Safety: Hotel Housekeeping

Typically, in this case study, housekeepers were responsible for cleaning 16 rooms per shift. The actual amount of work depends on the size of the room and the number of beds. A housekeeper needs between fifteen and thirty minutes to do one room.

With 256 standard cabins, 16 crew cabins, and luxury suites that can be divided into max 16 suites. With housekeeping servicing each room once per week. Working 6 days per week, that requires 3 housekeepers.

Canadian Centre for Occupational Health and Safety: Hotel Laundry

loading bins which weigh 27 kg (60 lbs) of dry laundry, and 55 kg (120 lbs) when wet
...
In one eight-hour shift, 20 bins of laundry are processed by two workers (Figure 1). The dry laundry is handled four times – 27 kg (60 lbs) x 4 handlings x 20 bins = 2,200 kg (4,800 lbs); the wet laundry is handled twice – 55 kg (120 lbs) x 2 handlings x 20 bins = 2,200 kg (4,800 lbs). The workload is distributed evenly, so each worker handles approximately 2,200 kg (4,800 lbs) of laundry every day.

This is by weight. Clothing weight
Per person per week:
1 bath towel @ 700g
1 hand towel @ 350g
2 single sheet cotton @ 350g
1 pillow case cotton @ 200g
7 briefs cotton-mix @ 40g
2 pairs socks cotton-mix @ 50g
2 jeans @ 700g
7 shirts synthetic @ 200g
Total: 5.13kg
For 1,200 passengers + 66 crew, that's 6,494.58kg per week. At 27kg per bin, that's 240 bins. With 20 bins per shift with 2 workers, that will require 4 workers to complete in 6 days.

Using the example of SS City of New York, I estimated 8 housekeeping workers. This more detailed analysis says 7 housekeeping (3 room maids, 4 laundry). Stick to the original 8?

::Edit:: Laundry can be done with 2 shifts per day, 2 workers per shift. That means they won't trip over each other.

Last edited by RobertDyck (2021-01-25 13:31:35)

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#613 2021-01-25 02:54:27

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
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Re: Large scale colonization ship

The movie "Passengers" showed a much larger ship than I'm proposing. I tried to time how quickly it rotates. It appears to be 1 rpm, 60 seconds per rotation. Here's a view out a window. My ship won't have a swimming pool, and won't have Jennifer Lawrence, but...
tumblr_osq6nrGp0T1uyg4r8o1_540.gif
tenor.gif?itemid=13698416
::Edit:: My ship is a wheel, windows on one side of the wheel or the other. That means windows facing aft will face the Sun, windows facing forward will face stars. As the ship rotates, stars will appear to move sideways across the window. Starship Avalon in the movie had 3 separate sections twisted in a helix, so windows faced to the side. That makes the stars appear to move up. Different direction.

Last edited by RobertDyck (2021-01-25 16:48:26)

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#614 2021-01-25 15:04:04

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Large scale colonization ship

Not sure if this has been suggested already: if the colonisation ship is placed on a Hohmann transfer orbit, there would appear to be no reason why it would need to expend propellant entering Mars orbit.  The passengers and freight that it carries obviously do.  But they can disembark from the ship in a much smaller vehicle, or within direct entry capsules.  If the time spent in the smaller transfer vehicle is less than a day, no one is going to care if they need to travel in airliner conditions to knock tens or hundreds of thousands of dollars off of their ticket.  Maybe there is a market for a relatively small and lightweight transorbital vehicle, that can dock with a passing passenger ship and transfer passengers and freight to a station on Phobos, from which they then travel to the surface via SSTOs.

Ps. If your ship gets built in the next 30 years, I don't think we can rule out the possibility of Jennifer Lawrence as a passenger :-)

A swimming pool sounds like a pointless extravagance.  However, it would provide good cosmic radiation shielding and a substantial reserve water supply.  You might as well do something useful with the water, rather than having it sit in a tank waiting for the time it may one day get used.

Last edited by Calliban (2021-01-25 15:16:04)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#615 2021-01-25 15:56:58

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
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Re: Large scale colonization ship

tahanson43206 and Calliban: thank you both for your encouragement. However, this is not an Aldrin Cycler. This is a ship designed to travel from Mars orbit to Earth orbit and back. A cycler has it's own problems. I feel it creates more problems than it solves. You can't unload passengers and cargo at a reasonable pace, it has to be done very fast, all at once as the cycler passes the planet. Loading the cycler with new passengers and cargo has to be done at the same time as unloading. Again, all at once, before the cycler leaves. How does a shuttle carry passengers from Mars surface to the cycler, rendezvous and dock, unload passengers, then return to Mars? The cycler is on its way back to Earth. All that would have to be done while in a trans-Earth trajectory. Basically, the shuttles to deliver passengers, cargo, supplies, and propellant to the cycler cannot return to Mars. Then how do you repair the cycler, or perform regular maintenance? It will always be enroute to one planet or the other. It cannot ever park in planetary orbit for maintenance.

By the way, a cycler is not in a perfect Hohmann transfer orbit. That would be the most energy efficient transfer orbit from one planet to the next. However, upon return it will reach the original planet's orbit when the planet is not there. For example, a Hohmann transfer orbit from Earth to Mars is 8.5 months one-way. That means 8.5 months return. After 17 month round trip, Earth will not be in the same place. Earth orbits the Sun every 12 months, so Earth will be 5 months past the rendezvous point. This means a cycler has to change its orbit with every planetary pass. That requires propellant. The ship can use gravity of the planets to help with course changes, reducing propellant required, but the cycler will always need some propellant.

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#616 2021-01-25 16:19:49

RobertDyck
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From: Winnipeg, Canada
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Posts: 7,782
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Re: Large scale colonization ship

Water: my ship design includes a water tank the full height of the sun-facing wall of the habitation ring. The ring with cabins is 19 metres wide, but only 2.43 metres (8 feet) high. Windows in that wall will pierce the water tank, which is why windows in that wall specifically will have 4 inches of mineral oil between two panes of window. The water will be 4 inches thick. Can you "thick" or "deep"? It's a wall, the tank built into the wall is the full height of the wall. I'll use the word "thick". The tank will have a bladder with 2 pockets. Basically a plastic bag with 2 parts. One part holds potable water, the other holds grey water. As passengers consume water for a shower, sink, or toilet, it will be processed. I could list all the recycling equipment, but it ends with grey water deposited in the other pocket of the bladder in the water wall. The cabin dehumidifier will deliver water to the water processing assembly, which deposits grey water to the bladder in the wall. This means as water is consumed from one pocket in the water wall, it ends up in the other one. So total volume of water in the water wall remains constant. Well, constant less any moisture temporarily in the toilet bowl, in the sink, or in the bottom of the shower. Final water processing will filter grey water to become potable; so drain water from one pocket in the water wall, deliver to the other. Again, total volume of in the water wall remains constant.

Again, the water wall protects the habitation ring only. It does not protect the observation deck, Mars simulation chamber, or greenhouses. They're all on the upper deck. tahanson43206 and I discussed making greater use of the second deck. I concluded the gym can be spread across two decks. However, that means if there's a solar proton event (solar flair or coronal mass ejection) then the upper deck will be off limits. The *ENTIRE* habitation ring is a big radiation shelter. That includes cabins, dining rooms, kitchens, bar, laundry, medical, bridge, and the lower deck of the gym.

So water is used for something useful.

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#617 2021-01-25 18:42:27

RobertDyck
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From: Winnipeg, Canada
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Posts: 7,782
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Re: Large scale colonization ship

I was wondering if people would question my list of laundry. My girlfriend claims women will have a lot more. Comments?

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#618 2021-01-26 07:32:33

tahanson43206
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Registered: 2018-04-27
Posts: 16,756

Re: Large scale colonization ship

For RobertDyck re topic ....

(laundry is good) (food is good) (rotation is good) (atmosphere is good) (waste treatment is good) (many aspects of Large Ship are good)

Please return to the critical path for a moment ... Let's go back to the beginning .... why do you need to fly through the atmosphere if you are not landing?

There has to be a reason grounded in something!

The recent discussion about Void's Ballistic Delivery idea has provided a number of useful facts to consider, including but not limited to GW Johnson's re-statement of the considerations for planning a flight to Mars.

(th)

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#619 2021-01-26 11:55:54

RobertDyck
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From: Winnipeg, Canada
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Re: Large scale colonization ship

It's a big ship. It will require a lot of propellant. We can eliminate propellant for Mars orbital insertion by using aerocapture. On simple principle of physics is traveling to the surface of Mars from Earth actually takes less propellant than the surface of the Moon. That may not be intuitively obvious. The reason is TMI for a Hohmann transfer does not take much more delta-V or propellant than TLI. Of course we use an express trajectory that uses 10% more propellant to reduce transit time from 8.5 months to 6. The express trajectory is the one for free return, so it's a safety thing.

But the big point is the reason Mars takes less propellant. The Moon has no atmosphere, so landing must be completely propulsive. Mars has an atmosphere, so a rover or lander can use direct entry to enter the atmosphere at interplanetary speed, use the atmosphere to slow down. Usually aeroshell, parachute, then small landing rockets like Viking or Phoenix. For an orbiter, the Moon requires propulsive orbital insertion. For Mars you can use aerocapture. If you don't use the atmosphere, you abandon the advantage of Mars.

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#620 2021-01-26 12:54:54

RobertDyck
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From: Winnipeg, Canada
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Posts: 7,782
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Re: Large scale colonization ship

Obviously propellant for return to Earth comes from Mars. Or one of its moons.

I suggested an open cycle gas core nuclear thermal rocket. That has the highest Isp of current technology. The version NASA talked about in the 1960s was estimated to have 6,000 seconds. However, developments of the 1990s should increase that to 9,000 seconds. Not my estimate, I read it. With high thrust. The catch is how do you recover the uranium when the engine shuts down? If it has to dump uranium at shutdown, that would be wasteful of uranium so expensive.

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#621 2021-01-26 13:14:38

tahanson43206
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Re: Large scale colonization ship

For RobertDyck re #619 and #620

Thanks for restating the reasons to plan to fly a passenger ship with 1000+ passengers and 60+ crew through the atmosphere of Mars.

If there is a trajectory that would allow you to enter orbit around Mars without spending more than fine-tuning propellant, would you be willing to consider it?

The discussion of the optimum trajectory for a flight to Mars seems to me to be ongoing.  The floor is the Hohmann Transfer trajectory.  It is the one that I'm pretty sure you are planning to use.  That trajectory has the distinct and immutable disadvantage that it delivers the spacecraft to Mars with a deficit in momentum, that has to be made up.

After thinking about the options available to you (after careful study) you have decided to invest in the hardware you will need to provide thermal protection for the vessel, and the reinforcement of flimsy structures to withstand the enormous stresses of passage through the atmosphere.

GW Johnson made a helpful comment in his recent post in the topic about a Ballistic Delivery System for Mars.  As I remember it, and paraphrasing (correction welcome if I missed something) the Hohmann Transfer trajectory delivers a vessel using it to Mars with the lowest possible velocity at the point it reaches Mars, of all the infinite alternative trajectories.

That tells me that there are other trajectories that can deliver the Large Ship to Mars without a deficit of momentum.

The ideal tool to find the optimum trajectory for a given flight probably already exists, and chances are it is in use in the major spacefaring nations.

SearchTerm:LargeShip discussion of reasons for atmospheric slowing (see posts 619 and 620)

(th)

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#622 2021-01-26 14:32:11

RobertDyck
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From: Winnipeg, Canada
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Re: Large scale colonization ship

No, I did not propose a Hohmann Transfer. I propose an express trajectory. Hohmann takes 8.5 months to transit to Mars. Express takes 6 months. One great advantage of express is that it's the only trajectory that gives a free return to Earth. Similar to Apollo 13, if something serious goes wrong, this trajectory uses the gravity of Mars to turn back toward Earth. The trajectory for Apollo was deliberately designed to do this, and a good thing because Apollo 13 had to use it. Returning from the Moon took 3 days, returning from Mars will take many months, but you will return. An express trajectory arrives at Mars with an excess of energy. That means the craft will have to slow in order to enter orbit.

Curiosity rover used Hohmann. Spirit and Opportunity used express.

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#623 2021-01-26 17:53:15

RobertDyck
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Re: Large scale colonization ship

We need a trajectory specialist. Using trajectories from Mars Direct, a trip to Mars will take 6 months, wait in Mars orbit 14 months, then return to Earth. Once in Earth orbit it will be a rush to offload passengers and cargo, reload the next group of passengers and cargo for Mars, load propellant and food and supplies, then you're off. That's far from ideal.

Ideal would be travel to Mars, remain in Mars orbit long enough to offload passengers and cargo, refuel, load food and parts for repair and maintenance, and enough time left to do repairs or maintenance before returning to Earth. Time between trips should be spent in Earth orbit, not Mars orbit. While waiting for planets to align, the ship could be used as a space hotel for tourists.

So how do we calculate a set of trajectories that do that?

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#624 2021-01-26 18:49:59

tahanson43206
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Registered: 2018-04-27
Posts: 16,756

Re: Large scale colonization ship

For RobertDyck re #622 and 623

Thanks for clarification about the trajectory plan you'd prefer .... the free return is definitely a bonus!

Thanks too, for the call for assistance ... I'll invite SpaceNut to consider how we might broaden our outreach effort ...

***
For SpaceNut ... if you have a bit of time, can you (would you) look for documentation on the Express trajectory ... GW Johnson may well have already covered it in his usual thorough manner.

For SpaceNut ... we have a new request to add to our recruiting effort ... A trajectory specialist (with access to the needed tools) would be a real plus for the team slowly assembling here.

One suggestion I do have is to see if we can find someone who GW Johnson would be comfortable working with.  GW keeps saying he's old as the hills and getting older, but I note that he does just fine withExcel,  Wordpress and a Windows 10 computer (when it's not cranky). 

(th)

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#625 2021-01-26 19:17:53

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,782
Website

Re: Large scale colonization ship

You know, I repair computers for a living. I am a software developer; lost my job when I won the nomination for the federal election and got buried. I taught intro programming using "C" language in the early '90s, and recently taught Office. I've done some advanced stuff in Office like VBA programming and OLE. If he needs help, I'm here.

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