Closed Ecosystems

Space settlement relevance

Orbital space settlements will be located between the planets. While the Sun will provide ample reliable energy, there are essentially no material resources in the immediate vicinity. All materials will need to be transported from Earth, the Moon, the asteroids, comets, or other planets and their moons. Thus, the space colony designer may assume ample energy but must conserve materials. Therefore, the life support system of the colony should recycle all materials.  Since we would prefer a life support system consisting primarily of plants, animals, and single-celled organisms, our life support system may be described as an ecosystem. Because our space colony's ecosystem is does not import or export materials, we call it a closed ecosystem.

 Space settlement ecosystem components

Relevant links

Lessons

Closed ecosystem construction and observation

In this lesson each student or team builds a close ecosystem and observes its development and/or decay.  Then, optionally, the class develops hypotheses based on the observations and runs experiments on a number of closed ecosystems to test the hypotheses.

Prepare the closed ecosystem

  1. Get a large clear bottle with a cap.
  2. Collect several plants, small animals, some soil, and some water. The water may contain pond scum or other living material.
  3. Place the collected materials into the bottle.
  4. If possible, puts a thermometer and/or other instruments into the bottle so that you can read them after the bottle is sealed.
  5. Put the cap on the bottle and seal the space between the cap and bottle with melted wax or other air-tight material.
  6. Place the bottle where it will receive at least indirect light. This is the energy source.
The class now has a number of closed ecosystems.

Observe development

 Try to determine whether each ecosystem was truly closed. It is quite likely that most of the initial closed ecosystems will die very rapidly. That's ok. Most things fail the first time. That's why we do this with bottles not astronauts.

Design and run experiments

  1. Examine the records and discuss the results of the closed ecosystems
  2. Form one or more hypotheses to explain why some ecosystems lived longer then others.
  3. For each hypothesis:
    1. Create two sets of 5-10 closed ecosystems where the sets differ in only one aspect chosen to test the hypothesis.
    2. Observe the development of these ecosystems.
    3. Determine if the hypothesis was correct.
    4. Write a report describing the hypothesis, background information, experimental method, and results. Discuss the meaning of the results in the last section of the report.
    5. Publish the report on a www server (see free www servers) and send email to globus@nas.nasa.gov so we can link to your results.