Human exploration of the solar system can be said to have begun with t
he Apollo missions. The Apollo Project was publicly funded with the na
rrow technical objective of landing human beings on the Moon. The tran
sportation and life support systems were specialized technical designs
, developed in a project management environment tailored to that objec
tive. Most scenarios for future human exploration assume a similar lon
gterm commitment of public funds to a narrowly focused project managed
by a government organization, which becomes a single customer for a l
arge industrial complex supporting the mission. Advocates of human exp
loration of space have not yet been successful in generating the polit
ical momentum required to initiate such a project to return to the Moo
n or to explore Mars. Alternative scenarios of exploration may relax s
ome or all of the parameters of organizational complexity, great expen
se, narrow technical focus, required public funding, and control by a
single organization. Development of the Moon using private investment
is quite possibly a necessary condition for alternative scenarios to s
ucceed.