The amount of energy needed to lift a man to the Moon is about 1000 kilowatt-hours and that costs only 10 to 20 dollars. The difference of nine zeros between this and the Apollo budget is a measure of our present incompetence.

Ultimately, there's no reason why space travel should be, in terms of future incomes, much more expensive than jet flight today.

Space communities will be established first on the Moon, then on Mars, and later on other worlds. But much closer to the Earth, orbital space stations of many kinds will be in wide use by the year 2000.

In May 1967, I was in Dallas to attend the first conference on the commercial uses of space, including tourism. Barron Hilton gave a talk on the Hilton Orbiter Hotel, which he hopes to see in his lifetime. Space tourism is going to be a major industry in the 21st century.

Another tremendously important use of space stations will be for medical research. One paper given at Dallas discussed the engineering problem of a hospital in orbit, which brings a poignant memory to mind.