Carl Sagan was a member of the scientific team that sent the Voyager One and Voyager Two space vehicles out of our solar system.

To test how the system works, the team tried making two different kinds of pores - some that were uniformly sized tubes, others that had a narrow bottleneck at one point and then widened out.

On the first level, two types of feasible structures are considered by one single enterprise. Influences of coefficients on choice of system are figured out by analysis of costs;