A training ground for astronauts, a laboratory for engineers trying to find what will work, the Johnson Space Center is a series of substitutions for outer space -- translated as brilliantly or crudely as current technology, ingenuity, and budgets will allow.

Complicated infrastructures create small zones suitably "pure" to simulate conditions elsewhere. Outer space certainly doesn't look like this, but if we want to simulate it here, this is the infrastructure we need.

It's all here: a lunar landscape set up for practice in Building 9; the Space Environment Simulation Laboratory in Building 32, where huge nitrogen tanks allow temperature to be varied from 260 degrees to minus 280 degrees Fahrenheit; and a circle enclosing 5.74 acres merely drawn onto the earth and dubbed, for a time, the Lunar Simulation Area.

Though the landscape might seem conventional, the logic is clearly that of another world: a place, here, that conforms to ideas and realities of somewhere else, far away. Here are the seeds of an idea that has reshaped the ways we live.