Why, four decades after men first ventured into space are there no regularly scheduled commercial flights into orbit? Some 35 years after the Wright brothers’ 1903 flight the commercially viable DC‑3 was flying. But today the cost of placing payloads into orbit on the Shuttle is perhaps a magnitude more than on Apollo. By contrast, in the past twenty years the cost of airline tickets per passenger mile have dropped by 30 percent, with twice as many people now flying. The costs of other goods and services have declined as well. The cost of shipping oil, for example, has dropped 80 percent.

For too long space enthusiasts have ignored economics at the peril of their passion. If men are to journey to Mars, markets are the means.