The author begins by describing how the very latest rocket propulsion
and spacecraft technology, and planned developments in nuclear and
electric propulsion technologies, are the key factors which will enable
a human expedition to Mars to take place. Of particular importance are
the challenges of transporting cargo to Mars and in providing necessary
life support for the crew, including the supply of consumables, such as
food, water, air and fuel, for the return journey. In this regard the
author considers how the International Space Station fits into the
strategy for a human journey to the Red Planet, in its preparation of
astronauts for long-duration spaceflight and the possible hazards posed
by space radiation and prolonged weightlessness. He concludes by looking
at the possible political obstacles to such a journey, but points out
that sooner or later humans will have to make a choice; stay here on
Earth or explore the Solar System beyond.