  We present an analysis of the economic, political and social factors that
underlay the Apollo program, one of the most exceptional and costly projects
ever undertaken by the United States in peacetime that culminated in 1969 with
the first human steps on the Moon. This study suggests that the Apollo program
provides a vivid illustration of a societal bubble, defined as a collective
over-enthusiasm as well as unreasonable investments and efforts, derived
through excessive public and/or political expectations of positive outcomes
associated with a general reduction of risk aversion. We show that economic,
political and social factors weaved a network of reinforcing feedbacks that led
to widespread over-enthusiasm and extraordinary commitment by individuals
involved in the project as well as by politicians and by the public at large.
We propose the general concept of ``pro-bubbles,'' according to which bubbles
are an unavoidable development in technological and social enterprise that
benefits society by allowing exceptional niches of innovation to be explored.
