Alone among all creatures, the species that styles itself wise, Homo sapiens, has an abiding interest in its distant origins, knows that its allotted time is short, worries about the future and wonders about the past.

Mars tugs at the human imagination like no other planet. With a force mightier than gravity, it attracts the eye to its shimmering red presence in the clear night sky. It is like a glowing ember in a field of ethereal lights, projecting energy and promise. It inspires visions of an approachable world. The mind vaults to thoughts of what might have been (if Mars were a litter closer to the warming Sun) and of what could be (if humans were one day to plant colonies there).

Alone among all creatures, the species that styles itself wise, Homo sapiens, has an abiding interest in its distant origins, knows that its allotted time is short, worries about the future and wonders about the past.

The American civil space program is growing to maturity. It has passed through the joys and crises of precocious childhood and now is being called upon to do grown-up things, like earn a living and establish permanent roots in space.