Food

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A mix of fresh raw vegetarian food.

The amount of Food for human beings that can be brought from Earth to Mars is limited, and the logistics of a continued food transport for the long term is expensive. By definition, an autonomous colony needs it's own food production. Reasons for this are cost reduction and the achievement of independence from Earth. Last but not least, locally produced food can be of higher quality and fresh, including a natural mix of vitamins and minerals.

Food requirements

An average human requires about 2,7 kg of food per day, or 985 kg per year. A good target might be one tonne of food per year per colonist, to account for losses. Plants are composed of edible parts and non edible parts. The non edible portion is counted as biomass, and can be used for industrial production or recycled into the food production system. On average, of the solid parts of plants (not water) about 50% of a plant is edible and the rest is biomass. The following table presents a suggested diet based on the Canadian Food Guide.

Food, canadian food guide Weight of

food (gram)

kiloCalorie/kg Calories

per day

Fruit 500 500 250
Vegetables 750 300 225
Protein (meat and beans) 200 4 000 800
Dairy 750 420 315
Grains 240 2 100 504
Oils 40 5 000 200
Total 2 480 925 2 294

Note: Calories as expressed in food guides and nutritional documents are actually kiloCalories. so the Calories of column 4 in this table are actually kiloCalories.

Food that can be brought from Earth

  • Several varieties of dehydrated food.
  • Food that contains large amounts of fat and carbohydrates, such as nuts and dried meats.
  • Concentrated fruit juice.
  • Lightweight, high energy foods with a long shelf-life.

Local Production Methods

  • Vegetable can be grown in greenhouses or on green walls in order to close the carbon cycle.
  • Proteins, fat and carbohydrates can be produced by a biotechnological factory also known as biological reactors.
  • Animals, such as chicken or fish, may be raised in sections of greenhouses.
  • It takes 2000 to 3000 liters of water to produce 1 kg of meat, it only takes 100 liters of water to grow 1 kg of grain. Water will be a very valuable commodity on Mars, so the first generation of settlers may well be vegetarian by necessity. This may be mitigated by water recycling.
  • Growing insects and their larvae (e.g. flour worms or fly maggots) can provide valuable proteins and might consume mostly waste biomass‎. Pigs might be a more palatable alternative, of fish.
  • Algae can produce large amount of food and oil. However, is is impossible to survive only on algae in the long term(reference needed).
  • Some food (possibly genetically modified) may be grown in the Martian atmosphere. Results from the Phoenix lander indicate that some vegetables may be grown in caves safe from radiation(ref needed).

Nutrition and Energy Calculations

Calorie calculation
Unit 1 person 1000 persons
Human calorie intake kilocalorie/day 2300 2300000
Days per year 365 365
Energy per year kiloca 839500 839,500,000
Yearly energy production kilocal/m2 4700 4700
Area to feed humans m2 179 178,617

Food and crop energy and yields

The following table has been compiled from various sources. The values are high but remain bellow record yields and are usually for open field intensive agriculture unless otherwise noted. Most of the energy in plants is stored in the form of carbohydrates, that store about 4000 kilo-calories per kg.

On Mars, these crops could be grown year round, with supplemental artificial lighting, no weather, extra CO2 concentration and optimum irrigation and fertilization. Some Yields might then be significantly higher.

Food and crop yields
Food type Tonnes

/ha

kg

/m2

kilocalorie

/kg

kilocalorie

/m2

Notes
Apples, pears Australia 65 6.5 571 3714 https://www.goodfruit.com/calculate-target-yield/
Ontario 25 2.5 580 1450
Oranges, citrus Florida 130 13 470 6110 https://www.hort.purdue.edu/newcrop/morton/orange.html#Yield
Israel 50 5 470 2350 https://www.haifa-group.com/citrus-tree-fertilizer/crop-guide-growing-citrus-trees
Banana Puerto Rico 70 7 1000 7000 https://www.hort.purdue.edu/newcrop/morton/banana.html#Yield
Strawberries England 30 3 330 990 https://vegetablegrowersnews.com/article/tunnels-varieties-double-uk-berry-yields/
California 90 9.0 330 2970 Hydroponic https://cals.arizona.edu/strawberry/Hydroponic_Strawberry_Information_Website/Costs.html
Australia 150 15.0 330 4950 http://www.nuffieldinternational.org/rep_pdf/1450740021NickyMannFinalReport.pdf
Dwarf fruit trees California 72 7.2
Potato UK 50 5.0 850 4250 https://potatoes.ahdb.org.uk/sites/default/files/GB%20Potatoes%202016-2017.pdf
Sweden 26 [1] 2.6
Sweet potato california 27 2.7 860 2346 https://ucanr.edu/repository/fileaccess.cfm?article=54045&p=%20MKCWZJ
Tomatoes 150 15.0 180 2700
Water melon 36 3.6 300 1071
Cabbage 90 9.0 250 2250 https://www.kzndard.gov.za/images/Documents/Horticulture/Veg_prod/expected_yields.pdf
Beans 20 2.0 3470 6940 Hydroponic : https://uponics.com/hydroponics-yield/
watercress 25 2.5 110 275 https://ipmdata.ipmcenters.org/documents/cropprofiles/HIwatercress.pdf
Alfafla (luzerne) Jordan 180 18 230 4140 Hydroponic : https://www.hindawi.com/journals/isrn/2012/924672/
canola 3 0.3 8840 ? 2652
Rice China 17 1.7 1300 2210 http://www.xinhuanet.com//english/2017-10/16/c_136683786.htm
Wheat 10 1.0 3400 3400
Canada[2] 5.9
6[3] 0.6
Oats 4.3 0.4 3890 1673
3.2
Barley 7 0.7 3540 2478
soya 3 0.3 4460 1338
Corn 12 1.2 960 1152
Fodder Corn Canada[2] 50 5
Bamboo[4] 4 For wood type products

Meat production

Meat production may some day be artificial, but may for some time come from animals. Vegetable alternatives exist for meat, and usually require less energy for their production. Therefore producing meat may be a question of demand and opportunity, rather than a question of need. Animals can produce meat from unused biomass, but the demand for other uses may be higher than the demand for meat production.

Energy in meat and meat products and dairy products.
Food type kg

/m2

kilocalorie

/kg

kilocalorie

/m2

Notes
Meat 5000
fat 9000
protein 4000
Salmon 2080
Tilapia 1290
chicken 2390
milk 420
Eggs 1550

Feed conversion ratio (FCR) is a measure of efficiency. It is the ratio between the mass of feed and the mass of product output. For dairy cows, for example, the output is milk, whereas in animals raised for meat (such as beef cows, pigs, chickens, and fish) the output is the flesh, that is, the body mass gained by the animal, represented either in the final mass of the animal or the mass of the dressed output (from Wikipedia).

Feed conversion ratios
Livestock FCR
Beef 4.5–7.5 calculated on live weight gain[5]
Dairy
Pigs 3.8-4.5 About 1 for piglets, grows higher and higher with time[6]
Sheep 4-6, 40 4-6 on grain, 40[7] on straw. This is an example of the difference between the production from high value food and the production

from lower value biomass.

Poultry 1.6-2 A hen can lay up to 330 eggs per year. Maturation is about 40 days.

Note than hens and many birds may require gravity for feeding/drinking, and transportation to Mars may be a problem.[8]

Criquets 0,9-1.0 Seems unlikely to be below 1....[9]
Fish 1-1.5 Tilapia is 1[10]. Salmon about 1,3[11]. Higher for fish to fish conversion, almost 4 in many piscicultures.
Rabbits 2.5-3

Artificial food

There is no existing complete food than might be considered artificial.

  • See vitamins for the basic vitamin requirements that need to be obtained from food.
  • Industrial proteins and carbohydrates are not produced directly from base chemicals but require biological reactors. There are a number of experiments being done to produce artificial food from the output of biological reactors, but these have not, to this time(2019), been proven to be more economical that naturally produced food.
  • Beyond meat, a vegetable meat substitute, may be considered as artificial in some ways, but is more a modified food. Entirely vegetarian diets are possible.
  • In-vitro meat is possible, but requires large amounts of energy for its production. Modified vegetables, such as Beyond Meat might produce a better substitute.

See also

References