ASEN 5158 Space Habitat Design

11/13/2008

Eckart IV: Fundamentals of Life Support Systems

IV.3.1.2 (p. 95-102) Food Supply

Objectives

  1. Identify technology options for addressing food functional requirements
  2. Describe general processes employed by each
  3. Discuss pros/cons (trade factors and integration issues) associated with each

Functional Requirements: Meet nutritional needs of the astronauts in a safe and healthy manner

 

Consider physiological "need" (hunger) vs. Psychological "desire" (learned response)

Also consider shelf life, preparation needs and waste (packaging, leftovers and any non-edible portions)

Candidate Food System Technologies

 

n      Food Preparation

- Fluid immersion cooker

- Forced-convection oven cavity (for roasting and baking)

- Direct contact and/or radiant heating surface cooking processor

 

n      Food Distribution

- Dishes and silverware (Wash or disposable?)

 

n      Food Preservation Methods

- Ultra-high intensity sound

- Electromagnetic pulses

- High pressure

- Chemical additives

- Biotechnology

- Microbial additives

- Intense pulsed light

- Cryo-freezing

- Combination

 

n      Refrigeration Techniques

- Direct coolant loops to a space radiator

- Vapor-compression

- Thermoacoustic refrigeration

- Thermoelectric devices

USDA guidelines met for balanced meals, but other factors related to space flight such as energy expenditure in 0g, 1/6 g or 1/3 g may need to be assessed.

 

Unique physiological aspects of space flight also need to be considered (stress, bone and muscle atrophy, fluid balance, energy requirements, ‘stuffy head’, etc.)

 

Energy intake dependent on individual – ranged from 1910 – 3838 kcal/day per crewmember on first 24 shuttle missions

 

Diet and exercise relationship must also be considered

Current NASA criteria

  • Minimal in-flight preparation
  • Minimal waste (biomass and packaging)
  • Ambient stowage
  • Good taste

 

Also need to consider for longer durations

  • Stability
  • Variety
  • Production during mission

Palatability

·        Taste and smell related - loss of free convective aromas

·        Vision – aesthetically pleasing = more readily consumed

·        Hearing

·        Touch / Texture

Historical Overview

 

Mercury – formulated for ease of swallowing and digestion due to unknowns of micro-g effects

 

Gemini – increased variation, mostly dehydrated sources, finger foods or ‘food-in-a-tube’

 

Apollo – initially same as Gemini, later introduced thermostabilized and irradiated items

 

Skylab

49% dehydrated, 24% thermostabilized 15% natural form or ready to eat, 11% precooked and frozen, and 1% irradiated

Individually packaged in aluminum, galley for rehydrating and heating

Complaints of blandness led to additional condiment selection

Missions included metabolic studies, so nutrient composition was closely regulated

 

Shuttle and ISS

Mainly commercially available thermostabilized, rehydratable, intermediate moisture and natural form foods (nuts and cookies)

Salt and pepper provided in liquid form (water and oil, resp.)

Pre-assembled menus stored in dry form wherever possible and rehydrated

Galley provides hot and cold water

Convection oven available for heating

Colored coded labels for crewmember specific menus, but not controlled

 

Soviet and Russian

Similar evolution from food-in-a-tube to fresh food being highly desired by long duration crewmembers

Options – Bring it or Grow it

 

Bring it…

  1. Rehydratable food: One way to reduce weight and preserve food longer is through dehydration. Before consumption, the removed water has to be re-added to the food item, which is otherwise hard "like a rock." Thus, each pack of dehydrated foods has a label with the exact amount of water and soaking time needed for re-hydration. For example, the label of a sausage patty instructs to add 1 ounce of hot water and wait 3 to 5 minutes. Water is supplied by the Shuttle's fuel cells, which produce water as a byproduct of electrical power generation. Foods packaged in rehydratable containers include soups, casseroles like macaroni and cheese, appetizers such as shrimp cocktail and breakfast items like scrambled eggs.

  2. Thermostabilized food: Heat processed to destroy microorganisms and enzymes. Individual servings of thermostabilized foods are prepackaged for one serving and can be easily cut open after preheating. This food category includes products such as grilled chicken and ham, tomatoes and eggplants, or puddings.

  3. Intermediate moisture food: This term describes food items which are preserved by restricting the water available for microbial growth while retaining sufficient water to give the food a soft texture and allow it to be eaten without further preparation. Food items representing this category are dried peaches, pears and apricots, and dried beef.

  4. Natural form food: Food items such as nuts, granola bars and cookies are classified as natural form foods. They are ready to eat, packaged in flexible pouches and require no further processing before consumption in flight.

  5. Irradiated meat: Beef steak and smoked turkey are irradiated products. The meat is cooked, packaged in pouches and sterilized by exposure to ionizing radiation so that they are stable at ambient temperature.

  6. Frozen food: These foods are quick frozen to prevent a buildup of large ice crystals. This maintains the original texture of the food and helps it taste fresh. Examples include quiches, casseroles, and chicken pot pie.

  7. Fresh food: These foods are neither processed nor artificially preserved. Examples include apples and bananas.

  8. Refrigerated food: These foods require cold or cool temperatures to prevent spoilage. Examples include cream cheese and sour cream.

Grow it…

 

VI.5 Fungi and Conversion of Inedible Plant Material for Food Conversion

 

            Conversion of inedible biomass from crop harvest

            Enzymatic hydrolysis – natural process, enzymes can be produced by fermentation

            Fungal conversion

            Protein extraction

            Lipid (fat) extraction

 

VI.6 Animals as Human Food

 

            Inefficiency factors must be addressed

            Some more efficient sources – fish, milk and chicken

                        Small mass, short life cycle preferable

            Crew time for tending and preparation

            CELSS equilibration challenges

           

VI.7 Aquaculture

 

            Rapid growth (~6-12 months), steady state production (~12-18 months)

            Tilapia commonly considered

            Omnivores may help with CELSS functions (carp, crustaceans, crawfish, etc.)

            Maintenance and breeding challenges must be addressed

            Large mass of water required – emergency buffer?

            CEBAS AQUARACK experiments balanced ecosystem, CO2 producers/consumers

 

VI.8 Food Management (Production, Storage and Processing)

 

            P/C systems cannot produce food, so all must be brought

            Water can be reprocessed for dehydrated food mass, however

            Generally accepted that production will be gradually phased in

            Benefits include reduced food launch mass due to recycled wastes

            Shelf life issues - stored food must be stabilized

                        thermostabilized, irradiated, dehydrated, refrigerated

            Preparation by rehydration or heating (and remember, no natural convection in 0g)

Summary

 

Briefly summarize historical context

Sum up total mass Human I/O and calorie data

What about leftovers?

Identify processing / preparation requirements

Consider variety (to an extent)

Investigate other applications (military, backpacking, etc.)

Address packaging, including novel concepts

            biodegradable / edible packaging

            dual use material

            individual vs. bulk packaging

            ratio of edible : non-edible, typical fraction

            etc.

 

What are impacts of food in terms of spacecraft and/or ECLSS design?

 

  1. Launch Mass (transitions to other subsystems)
  2. Storage Volume (decreases over time)
  3. Power (storage and preparation)
  4. Waste (mass & volume increase over time)      includes packaging and biomass ~ leftovers?
  5. Integration potential (instead of just waste)
  6. Subsystem responsibility?
                different impact level for short/long missions

 

Some interesting ‘food for thought’…

 

http://www.wired.com/news/space/0,2697,64976,00.html?tw=wn_19techhead

http://spaceflight.nasa.gov/living/spacefood/index.html

http://spaceflight.nasa.gov/shuttle/reference/factsheets/food.html

http://www.space.com/scienceastronomy/generalscience/food_819.html

http://inventors.about.com/library/inventors/blfrdrfood.htm

http://home.howstuffworks.com/food-preservation4.htm

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

http://theepicenter.com/mre_military_meal_ready_to_eat.html

 

NASA Food Technology Commercial Space Center - http://www.ag.iastate.edu/centers/ftcsc/index.htm

 

The challenge for NASA FTCSC is to develop new processes and products that will permit astronauts to feed themselves with a combination of foods prepared on Earth and food products from crops produced in space. Food systems must be developed for both short- and long-term missions, including 90-day missions on the International Space Station and one- to three-year missions on outposts on the moon or Mars. The mission of the NASA FTCSC is to engage the food industry and academia to develop these food systems.

 

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