Author Topic: MCT Speculation and Discussion Thread 4  (Read 610560 times)

Online guckyfan

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Re: MCT Speculation and Discussion Thread 4
« Reply #1580 on: 02/03/2016 09:59 AM »
Flatulence is a great resource for ISRO production of propellant.  ;)

You think India is building a methane engine? ;)

Online Lampyridae

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Re: MCT Speculation and Discussion Thread 4
« Reply #1581 on: 02/03/2016 10:42 AM »
If you're going to Mars for years, drinking a protein shake on the way is going to be the very least of your psychological worries, I PROMISE you. Ridiculous.

Might as well send people there naked too, or at least in briefs. The mass of clothes adds up. Shave everybody bald before the flight... could save 500gm or so for people with long hair. Offer lower prices to women since they have lower life support requirements and mass less and take up slightly less space. Pre-launch laxatives to clear the digestive systems of unneeded mass and minimise the upchuck on-orbit. Repurpose privacy partitions to be worn as clothes. Acceleration couches may as well be removed to be used as furniture on the surface. But why acceleration couches? Surely a hammock is just as good. Which can be turned into partitions. Which can be turned into clothes on arrival...

It will certainly be smelly aboard these MCTs.

Hmmm. Lots of unpleasant things I can do to these econocolonists.
« Last Edit: 02/03/2016 10:43 AM by Lampyridae »
SKYLON... The League of Extraordinary Gentlemen's preferred surface-to-orbit conveyance.

Offline Krevsin

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Re: MCT Speculation and Discussion Thread 4
« Reply #1582 on: 02/03/2016 11:18 AM »
If you're going to Mars for years, drinking a protein shake on the way is going to be the very least of your psychological worries, I PROMISE you. Ridiculous.
I am reminded of a proverb involving the backs of camels, straws and breaking.

People will tolerate a lot of discomfort, but what will finally break a person is usually something seeming relatively petty in the grand scheme of things.

Online guckyfan

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Re: MCT Speculation and Discussion Thread 4
« Reply #1583 on: 02/03/2016 11:29 AM »
I am reminded of a proverb involving the backs of camels, straws and breaking.

People will tolerate a lot of discomfort, but what will finally break a person is usually something seeming relatively petty in the grand scheme of things.

Yes, but we are talking about a few months of transfer. That the diet on Mars needs to be a lot better for colonists I think no one would dispute. I don't think that Soylent is the way to go but it is an option for the trip.

Offline JamesG123

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Re: MCT Speculation and Discussion Thread 4
« Reply #1584 on: 02/03/2016 11:44 AM »
Hmmm. Lots of unpleasant things I can do to these econocolonists.

It would make for spectacular "Mars One" ratings... :o

Offline Krevsin

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Re: MCT Speculation and Discussion Thread 4
« Reply #1585 on: 02/03/2016 12:48 PM »
I am reminded of a proverb involving the backs of camels, straws and breaking.

People will tolerate a lot of discomfort, but what will finally break a person is usually something seeming relatively petty in the grand scheme of things.

Yes, but we are talking about a few months of transfer. That the diet on Mars needs to be a lot better for colonists I think no one would dispute. I don't think that Soylent is the way to go but it is an option for the trip.
"A few months" is still a very long time for a human to live through. Remember, there's not much to really do during the transfer. Sure, there's exercise, some leisure activities (reading, watching TV, various games, et cetera) and the occasional maintenance work to occupy your time. Boredom might be a serious morale issue and you do not want to compound that issue with a bland diet.

Offline Burninate

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Re: MCT Speculation and Discussion Thread 4
« Reply #1586 on: 02/03/2016 01:29 PM »
I agree that going to a super restricted diet wouldn't be good. But consumables mass could still be quite low without that extreme.

A) Where do you get 5kg/day?

Basic human life support requirements per day are about 5kg - less than 1kg oxygen, less than 1kg dry food, and over 3kg water (including water in food).

This assumes either doing something other than normal bathing, or 100% recycling of cleaning water.
Quote
B) Wait, what?  10 cargo missions per crew mission... of MCT?

I believe Musk tweeted that.

Quote
And how many propellant missions per crew mission is that?

I don't know... depends on the size of MCT and the architecture.

Quote
If you limited it to 6km/s each = 5:1 mass ratio @ 380s (probably not reasonable, given 3.2 C3, 0.5 minimum to MTO, more for single-synod reuse, and largely propulsive SSRP EDL), 40 prop launches to feed 10 cargo launches

That assumes that the MCT arrives in LEO empty.

If BFR is really too large for any existing pad, I would expect MCT to either go to a higher energy orbit than LEO or arrive with significant propellant.

But cost per launch will nonetheless have to be incredibly low by current standards.

Why would an MCT arrive in LEO (with around 200 tons, per Shotwell) packing 50 tons of propellant in place of 50 tons of gear?  When half of you are performing increasingly desperate reasoning-from-first-principles and begging-the-question ("Oh come on, I can drink 3000 calories of vegetable oil...") to reject NASA's estimate of consumables?  When 50 tons of propellant would send MCT... directly into the inner Van Allen belt and no further?  What does BFR being too large for any existing pad have to do with it?
« Last Edit: 02/03/2016 01:37 PM by Burninate »

Online Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #1587 on: 02/03/2016 02:24 PM »
I drink Soylent for lunch. This is not "drinking 3000 Calories of vegetable oil."

Building a colony transporter with the economics needed to make it feasible is not something that has ever been done before. It most CERTAINLY will involve thinking from first principles, as Musk is wont to do.
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Offline oldAtlas_Eguy

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Re: MCT Speculation and Discussion Thread 4
« Reply #1588 on: 02/03/2016 04:03 PM »
I drink Soylent for lunch. This is not "drinking 3000 Calories of vegetable oil."

Building a colony transporter with the economics needed to make it feasible is not something that has ever been done before. It most CERTAINLY will involve thinking from first principles, as Musk is wont to do.
The first principle in Musk's mind is cost followed by almost eliminating training, which is also a major cost. That would include using normal diet, fresh like foods. Each MCT would need a core group that is the operator/maintainers but most of the group of 100 are just passengers along for the ride with little training. Many of the specialists/crew may not be colonists and return. Similar to a ocean passenger ship crew.

Offline Burninate

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Re: MCT Speculation and Discussion Thread 4
« Reply #1589 on: 02/03/2016 04:44 PM »
I drink Soylent for lunch. This is not "drinking 3000 Calories of vegetable oil."

Building a colony transporter with the economics needed to make it feasible is not something that has ever been done before. It most CERTAINLY will involve thinking from first principles, as Musk is wont to do.
The first principle in Musk's mind is cost followed by almost eliminating training, which is also a major cost. That would include using normal diet, fresh like foods. Each MCT would need a core group that is the operator/maintainers but most of the group of 100 are just passengers along for the ride with little training. Many of the specialists/crew may not be colonists and return. Similar to a ocean passenger ship crew.
The NASA estimates are nowhere near a normal diet or fresh-like foods.  Those foods are shelf-stabilized in some way, and there's no food freezer or refrigerator, and they're dehydrated wherever it's practical.   28% water content by mass is extremely low for foods that can be eaten without only a minimal kitchen.

http://www.cnet.com/news/houston-we-have-a-tortilla-problem/

While we're on that example, how much water content is in the food *you* eat?

Let's take a typical flour tortilla from a supermarket:
http://www.caloriecount.com/calories-mission-foods-8-premium-flour-i99186

These are bland, highly refined foods that we would expect to be almost completely digestible;  Subtract the macronutrients from the weight and you will find a decent estimate for water content.  We actually tend to lump the indigestible vegetable matter into carbs as 'fiber'.

(47g weight - (18g carbs + 3g protein + 3g fat)) / 47g weight = 49% water by mass.  While typically you put something wet on one, I can just about palatably eat a flour tortilla dry (unlike a corn tortilla).


How about something we already dehydrate?  Grapes / raisins are probably the most popular.

http://nutritiondata.self.com/facts/fruits-and-fruit-juices/2050/2

(165g weight - 138g macronutrients) / 165g weight= 16% water by mass.


Maybe something we tend to keep on the shelf?  How about dry rice?  Hell, we use that to literally dehydrate things (like phones) that get too much water on them, by sucking moisture out of the air.

http://nutritiondata.self.com/facts/cereal-grains-and-pasta/5711/2

1 - 162/185 = 12.4% water by mass.

When we cook it:

http://nutritiondata.self.com/facts/cereal-grains-and-pasta/5804/2

we raise it to 1-(45+4)/158 = 69% water by mass.


Let's try a shelf-stabilized energy bar (designed to be a precooked meal replacement sitting next to your water bottle):

http://www.clifbar.com/products/clif-bar/clifbar/banana-nut-bread#nutrition

1-58/68= 15% water by mass.  Impressive.




Continuing on, how about what I just had for breakfast?


Eggs

http://nutritiondata.self.com/facts/dairy-and-egg-products/120/2

1-56/220 = 75% water


Bread

http://nutritiondata.self.com/facts/baked-products/4876/2

1-17/28 = 39% water


Banana

http://nutritiondata.self.com/facts/fruits-and-fruit-juices/1846/2

1 - 54/225 = 76% water
« Last Edit: 02/03/2016 05:09 PM by Burninate »

Offline Burninate

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Re: MCT Speculation and Discussion Thread 4
« Reply #1590 on: 02/03/2016 04:50 PM »
I drink Soylent for lunch. This is not "drinking 3000 Calories of vegetable oil."

Building a colony transporter with the economics needed to make it feasible is not something that has ever been done before. It most CERTAINLY will involve thinking from first principles, as Musk is wont to do.
The problem is not thinking from first principles, it's rejecting actual research that's been done and the optimum that's been chosen in a program where every kilogram costs $30,000 extra, which has plenty of incentive to minimize mass and ramp up the ECLSS;  And ensuring everyone that this is all an irrelevant, useless assessment, because you choose to drink Soylent for lunch sometimes.
« Last Edit: 02/03/2016 04:51 PM by Burninate »

Online RonM

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Re: MCT Speculation and Discussion Thread 4
« Reply #1591 on: 02/03/2016 05:05 PM »
I drink Soylent for lunch. This is not "drinking 3000 Calories of vegetable oil."

Building a colony transporter with the economics needed to make it feasible is not something that has ever been done before. It most CERTAINLY will involve thinking from first principles, as Musk is wont to do.
The problem is not thinking from first principles, it's rejecting actual research that's been done and the optimum that's been chosen in a program where every kilogram costs $30,000 extra, which has plenty of incentive to minimize mass and ramp up the ECLSS;  And ensuring everyone that this is all an irrelevant, useless assessment, because you choose to drink Soylent for lunch sometimes.

Yes, a lot of effort has gone into this subject. No need to throw that reseach out the airlock. NASA has a variety of dehydrated foods that are very mass efficient. So does private industry. While Soylent or something like it can be part of the food selection, there is no reason to make it the only food.

Offline Burninate

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Re: MCT Speculation and Discussion Thread 4
« Reply #1592 on: 02/03/2016 05:45 PM »
Another interesting food tidbit:

http://www.pbs.org/newshour/updates/astronauts-crave-tabasco/

Apparently microgravity nasal congestion dulls the sense of smell aboard the ISS, so despite problems with wafting odors, familiar foods tend to taste unpleasantly sweet or bland ("like plastic"), and astronauts tend to go in heavy on the spicy stuff.

Offline Paul451

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Re: MCT Speculation and Discussion Thread 4
« Reply #1593 on: 02/03/2016 08:13 PM »
A space freezer can be an air lock opened to space for some foods.

No it can't. "Space" isn't cold. It's a vacuum. If you keep your food in an open airlock, it will have the same temperature as any other section of the ship's hull, which will be whatever temperature it is radiating at. (Probably room-temperature, for obvious reasons.)

Food has been consistently rated the most important morale boosting thing Astronauts get

Astronauts are crew. Crew morale is important. Colonists are cargo. Only their survival rates matter.

But seriously, I think people are getting themselves knotted up over this. Things like Soylent merely give you a simple number to use as your starting point. If you can't close your case with such products, you ain't gonna do better with more reasonable foods. Now once you've crossed your eyes and dotted your tea, if you still have mass budget left over, by all means add some tinned tomatoes or an entire greenhouse module. But you have to start somewhere.

(Musk himself may just end up adding an extra supply ship, because "fuel is cheap".)

Online Robotbeat

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Re: MCT Speculation and Discussion Thread 4
« Reply #1594 on: 02/03/2016 09:11 PM »
I drink Soylent for lunch. This is not "drinking 3000 Calories of vegetable oil."

Building a colony transporter with the economics needed to make it feasible is not something that has ever been done before. It most CERTAINLY will involve thinking from first principles, as Musk is wont to do.
The problem is not thinking from first principles, it's rejecting actual research that's been done and the optimum that's been chosen in a program where every kilogram costs $30,000 extra, which has plenty of incentive to minimize mass and ramp up the ECLSS;  And ensuring everyone that this is all an irrelevant, useless assessment, because you choose to drink Soylent for lunch sometimes.

Yes, a lot of effort has gone into this subject. No need to throw that reseach out the airlock. NASA has a variety of dehydrated foods that are very mass efficient. So does private industry. While Soylent or something like it can be part of the food selection, there is no reason to make it the only food.
Completely agree.
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Offline Hotblack Desiato

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Re: MCT Speculation and Discussion Thread 4
« Reply #1595 on: 02/03/2016 09:41 PM »
Regarding weight and water content in food: how about freeze drying?

It can be done on earth, is a well understood process and reduces the weight of the food.

Of course, not everything can endure freeze drying, for example meat can be freeze-dried, but reconstituting it turns it into a slurry (still edible), although apparently it works with bacon. There are plenty of other types of food which can endure freeze-drying.

A system that cleans water (maybe via active coal, can be regenerated, and reverse osmosis) allows reduction of the mass without losing too much of the quality.

Okay, the quality will be like instant meals (add water and heat), but they are not so bad either. That stuff just needs adjustion to the different environment, as earlier pointed out, it needs to be spicier (will martians be chili-heads?).

Online TomH

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Re: MCT Speculation and Discussion Thread 4
« Reply #1596 on: 02/03/2016 09:46 PM »
..meat can be freeze-dried, but reconstituting it turns it into a slurry.....

I spent a lot of summers of college and grad school working as a wilderness guide. I never had much problem with any kind of freeze dried meat: beef, chicken, ham, shrimp. And I ate a lot of it over the years.

Online docmordrid

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Re: MCT Speculation and Discussion Thread 4
« Reply #1597 on: 02/03/2016 09:50 PM »
I drink Soylent for lunch. This is not "drinking 3000 Calories of vegetable oil."

Building a colony transporter with the economics needed to make it feasible is not something that has ever been done before. It most CERTAINLY will involve thinking from first principles, as Musk is wont to do.
The problem is not thinking from first principles, it's rejecting actual research that's been done and the optimum that's been chosen in a program where every kilogram costs $30,000 extra, which has plenty of incentive to minimize mass and ramp up the ECLSS;  And ensuring everyone that this is all an irrelevant, useless assessment, because you choose to drink Soylent for lunch sometimes.

Yes, a lot of effort has gone into this subject. No need to throw that reseach out the airlock. NASA has a variety of dehydrated foods that are very mass efficient. So does private industry. While Soylent or something like it can be part of the food selection, there is no reason to make it the only food.
Completely agree.

What's the sodium content of the NASA foods? The commercial versions have near edema inducing levels.
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Offline Burninate

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Re: MCT Speculation and Discussion Thread 4
« Reply #1598 on: 02/03/2016 10:24 PM »
Nobody seems to be reading the links I posted, so I'll post them again:

An assessment of long-run consumables needs:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150003005.pdf

Two articles on ISS food:

http://www.cnet.com/news/houston-we-have-a-tortilla-problem/

http://www.pbs.org/newshour/updates/astronauts-crave-tabasco/




Regarding weight and water content in food: how about freeze drying?
While freeze-drying saw a number of earlier applications in food processing & medical products, eating freeze-dried food was basically popularized by products developed for NASA's short-duration spaceflights in the 60's.  If you ever go to the NASM you'll probably walk away with souvenir 'Astronaut Ice Cream', developed under contract for NASA in 1968, or a package of freeze dried strawberries.

I think it's still used for some portion of the menu, but a lot of freeze dried food is not very palatable or is hard to rehydrate, per NASA's history of its space food program at:

http://www.nasa.gov/audience/forstudents/postsecondary/features/F_Food_for_Space_Flight.html


What's the sodium content of the NASA foods? The commercial versions have near edema inducing levels.
This is handled in the PBS link.

You can guess that it was roughly in line with the RDA before the ISS program, but... NASA decided during the ISS program that the optical hypertension they were observing in long-duration spaceflight was worrying enough that they cut planned sodium intake by half, eliminating basically all commercial food options.  In my experience commercial canned savory foods, and also many frozen prepared foods and restaurant dishes, tend to have 2 to 10 times as many miligrams of sodium as they have calories of macronutrients;  This ratio has been useful for me in cooking for someone with a 2000mg/d diet (the right ratio is 1:1 on average).  IMO, the only way the US gets away with an average as low as 3400mg a day is by replacement of many savory dishes with heavy use of sugary foods & soft drinks, which the American palate does not require to be salty.

A system that cleans water (maybe via active coal, can be regenerated, and reverse osmosis) allows reduction of the mass without losing too much of the quality.

You're pushing a steam engine on a rocketry program.  The ISS ECLSS is extremely sophisticated, and recovers (if the estimates in the first link are based on that, as I suspect), ~85% of water lost to the toilet, and ~100% of everything else.
« Last Edit: 02/03/2016 11:59 PM by Burninate »

Online docmordrid

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Re: MCT Speculation and Discussion Thread 4
« Reply #1599 on: 02/03/2016 10:39 PM »
I'll eat most any food so long as the place is well stocked with sriracha or habaņero sauce. Sign me up.
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