About 30 years ago an engineer (Gerard O'Neill) noted that a basic impediment to the colonization of space and the expansion of the human race to other parts of the universe is a simple, inexpensive design for human habitation. What he proposed has come to be known as an O'Neill colony or trash can colony. For a pile of related information and renderings check out the site at http://www.nss.org/settlement/nasa/index.html . (Here's another good link) In true engineering tradition he worked out and published all the structural details for such a colony using technology available at that time. There are an incredible number of intertwined issues that had to be resolved during this process. These include such considerations as adjustable solar radiation protection, sufficient solar illumination to allow plants to grow, heat rejection, and sources for raw materials. One of the most intriguing ideas he had was to build such colonies at the Lagrange points of the earth-moon system. These are points that can be found in the gravitational fields surrounding many two body systems. At these points the net gravitational forces are such that an object of negligible mass placed at the Lagrange point remains there (a sort of solar system equivalent of the Sargasso Sea). A colony built at such a location would require only minimal amounts of fuel to remain in position. Additionally, it is expected that over the lifetime of the solar system a large number of meteoric bodies have accumulated there providing ready building material for the colony.

In this lab you will consider some similar interrelated design issues. The constraints are admittedly artificial but they are rooted in reality. The question is which one do you consider first? Which one is the most limiting? How do you begin? A perfectly reasonable approach is to start with the first constraint and find a solution to it. Then try the second and see if you have to adjust your solution to the first constraint. This approach will work. Another approach proceeds by writing down all of the constraints as a set of mathematical equations with multiple variables. Treat these equations as a normal system and try to solve it. What will usually happen is that there are too many variable for the number of equations. You then have to arbitrarily assign a value to some of the variables to make the system solvable. Your choices may lead to an unsolvable system and require that you go back and try again. See how it goes!