Martian Farming Case

Page 1“Farming in Space?” by Joyner and Allen

NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Problem Statement Congratulations! Y ou are leaving Earth forever. You are selected to be part of a mining colony of 100 people located on the planet Mars. Before you head to Mars, however, you need to fi gure out how to feed yourself and your colleagues once you are there. Your group is tasked with selecting the foods to be grown on Mars.

Suppose that enough food can be taken to supply the entire colony for several months (approximately 90 days). After this, food for the colony must come from what can be grown. Th e colony manager is instructed to keep costs as low as possible while still providing a sustainable food supply that meets the nutrient requirements for adult humans. You may assume that all of the colonists are healthy adults of average height and weight with no known food allergies.

By the time you arrive on Mars, a dome-like structure will already be in place to maintain an Earth-like air composition, pressure, and temperature. Within this dome there are 1000 acres available for growing foodstuff s. You can bring seeds, soil, and fertilizer with you, but keep in mind that seeds require time to germinate and grow to maturity, and diff erent plants have diff erent growth requirements. Additionally, certain foodstuff s require more fertilizer than others, which is additional weight you must bring with you, increasing the cost of the trip.

Some Mars facts: Mars has a 687d orbital period and a 24h 40m day-night cycle, and sunlight is about 44% as intense as at Earth. Mars has plenty of carbon dioxide and water for your use, but you will still need to collect it and recycle all that you use. Th e soil and air are extremely poor in carbon and nitrogen compounds, hence the need for fertilizers and other organics. Outside of your dome, the air pressure will be at most about 1% that at Earth’s surface. Th e outside day-night temperature will vary by 60 to 80°C, with a daytime maximum above the freezing point of water during the summer. Martian-analog soils on Earth would include those of the ash-infused Columbia plateau in North America, and the Dry Valleys of Antarctica.

Your problem-solving method will proceed thus: • In Part I, you will identify some potential challenges related to sustainable agriculture. • In Part II, you will choose fi ve criteria to be used for ranking potential Martian crops. • In Part III, you will use your criteria to rank a list of given crops and identify the top three. • In Part IV, you will refl ect upon the context of the problem, the method of solution, and the results, and

thereby identify strengths and weaknesses.

Developing a Sustainable FoodDeveloping a Sustainable Food Supply on MarsSupply on Mars

by Helen S. Joyner, School of Food Science, University of Idaho, Moscow, ID Michael L. Allen, Department of Physics and Astronomy, Washington State University, Pullman, WA

Farming in Space?Farming in Space?

 

 

NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Page 2“Farming in Space?” by Joyner and Allen

Part I – Sustainability Considerations In an inhospitable environment such as the Martian surface, sustainability becomes a major issue. Sustainability implies that whatever resources are used to grow crops (e.g., water, fertilizer) can be replaced so that the growth of crops can continue, producing the same quantity and quality of crops indefi nitely.

Questions 1. As a group, write down two challenges in terms of sustainability you would face when developing a sustainable

food supply for a Martian colony (or any area that is severely lacking in agricultural resources). Keep in mind the space and time limitations you have (1000 acres of growing space and several months’ worth of food).

2. A sustainable food supply requires more than just resource management. It also needs to provide people with suffi cient calories, macronutrients, and micronutrients for health, productivity, and well-being. Write down at least two challenges of producing such a diet sustainably in an area severely lacking in agricultural resources.

 

 

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Page 3“Farming in Space?” by Joyner and Allen

Part II – Selecting Criteria for Growing Foods From the list below, choose the fi ve most important criteria for selecting appropriate foods to grow in the Martian colony, keeping in mind the constraints given in the problem statement and your responses to the previous questions. Write a paragraph justifying why these fi ve are the most important.

• Water usage • Fertilizer usage • Space required for growth • Yield • Post-harvest processing required • Waste generation • Total kilocalories provided • Protein content • Carbohydrate content • Fat content • Micronutrient content • Additional structure needed for growth/processing/storage • Time to grow to harvest • Labor/fuel required for growth/processing • Shelf life after processing

 

 

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Page 4“Farming in Space?” by Joyner and Allen

Part III – Foodstuff Selection After discussing colony needs and constraints with specialists in plant and soil science, you have generated a list of foodstuff s that could potentially be grown on Mars:

• Corn • Barley • Peas • Spinach • Fish • Rice • Potatoes • Soybeans • Broccoli • Oats • Wheat • Peanuts • Winter squash

Using the tables below, select the three foodstuff s that are optimal as determined from the fi ve criteria you chose in Part II. Ignore the other criteria when making your selection. Possible scoring systems include (but are not limited to) assigning more weight to criteria that are considered more important or assigning diff erent numbers of points to diff erent categories (e.g., high=1, medium=2, low=3).

If the criteria you select result in more than three optimal foodstuff s based on your scoring system, you must determine and justify a way to break any tied scores. Write a paragraph identifying your three chosen foodstuff s and justifying why they are the most appropriate to grow on Mars.

Water usage Fertilizer usage Space required for growth

Yield Post-harvest processing

Waste generation

Time to grow to harvest (fast

growth: low)

Labor required for growth & processing

Corn Medium High High High Medium High Low Medium

Rice High High High Medium High Medium Medium High

Oats Low Low High Low High Medium Low Medium

Barley Low Medium High Low High Medium Low Medium

Potatoes Medium High Medium High Low Low Medium Low

Wheat Low Medium High High High Medium High High

Peas Low Low Low Medium Medium Medium Low Low

Soybeans Medium Low Low Low Medium Medium High Low

Peanuts Low High Medium Low Medium Medium High Low

Spinach Medium High High Low Low Low Low Medium

Broccoli Medium High High Low Low Low Low Medium

Winter squash

High Medium High Low Low Low Medium Medium

Fish High Low Medium Low High Medium High High

Total calories provided

Protein content Carbohydrate content

Fat content Micronutrient content

Additional structure needed for growth, processing, storage

Shelf life after processing

Corn High Low High Low Medium Medium High

Rice Medium Low High Low Medium Medium High

Oats Medium Low High Low Medium Medium High

Barley Medium Low High Low Medium Medium High

Potatoes Medium Low High Low High Medium Medium

Wheat Medium Medium High Low Medium Medium High

Peas High Low High Low High Low High

Soybeans Medium Medium Medium Medium High Low High

Peanuts High Medium Medium High High Medium High

Spinach Low Low Low Low High Low Low

Broccoli Low Low Low Low High Low Low

Winter squash

Low Low High Low High Low Low

Fish High High Low Medium High High Low

 

 

NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Page 5“Farming in Space?” by Joyner and Allen

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Case copyright held by the National Center for Case Study Teaching in Science, University at Buff alo, State University of New York. Originally published October 2, 2015. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work. Licensed photo in title block © Dutchscenery | Dreamstime.com, id 28067696.

Part IV – Refl ection Discuss the following questions with the members of your group. Choose someone in your group to take minutes of the discussion.

Questions 1. In reference to Part II, are there criteria not listed that you would add to the list? If so, what would you add?

Would these criteria be ranked among your top fi ve? If so, then justify your choice.

2. In reference to Part III, are there foods not listed that you would add to the list? If so, explain why you would add these foods to the list and estimate values (high, medium, low) for each criterion. Include a formal reference to any information you have to look up. If you think the list is complete, explain why.

3. Consider your three best foods: could you survive indefi nitely on this diet? Be productive and healthy? Be happy? Why or why not?

4. Why do you think your group was restricted to only three foods?

5. How do you think your fi nal list of three foods would change if you included more than fi ve criteria for ranking each food?

6. Would you grow additional types of foodstuff s after developing the infrastructure to sustainably produce your three chosen foods? Explain your answer.

7. Part II lists 15 criteria for ranking foods. Which of these criteria are related to sustainability? Justify your selections.