As we enter a new millennium, people the world over are reflecting on the accomplishments of the past and speculating about opportunities of the future. This document discusses human exploration and development of space.

The work described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology under a contact with the National Aeronautics and Space Administration. The support of the NASA Headquarters Office of Chief Engineer for the development and documentation of the force limited vibration testing technology described in this monograph is gratefully acknowledged.

Science opens the door to speculations about Man's future. This book speculates about space travel in the far distant future based on our understanding of elementary particle physics, astrophysics and gravitation. It is technical in part (some math) although much of the material is understandable to the layman. Its theme: In tens of thousands of years Man may reach beyond our universe to countless other universes located in the space beyond our universe that we call the Multiverse. The multiverse is an infinite 16-dimensional flat space that we call the Flatverse. We see reason to believe that an infinity of universes, including our own universe, may exist within the Flatverse. They are separated generally by large distances - trillions of light years - island universes containing matter and energy. The all-enveloping Flatverse is like a desert - no matter and no energy - with universes dotting the Flatverse like oases. This book makes a leap of tens of thousands of years of research and development - perhaps 50,000 years (four times the approximately 12,500 year period from human hunter-gatherer clans to the present) - to describe travel to far universes from our universe. It describes the general features of a starship, called a uniship, for travel to other universes. Uniships differ significantly. Their drives must enable travel in fifteen different directions in the Flatverse. They require radically different mechanisms for seeing and navigating within the Flatverse. The mechanisms will have to accommodate using our 3-dimensional eyes to see and navigate in the 15-dimensional Flatverse space. The book proposes mechanisms for these purposes based on a fifth force of nature: a baryonic force that was suggested over sixty years ago. We show this force is embodied in a 15-dimensional field similar to the electromagnetic field. As the electromagnetic field enables us to see and navigate in three dimensions, so the fifteen dimensional baryonic field gives us eyes in fifteen dimensions. The book considers entry and exit from universes in some detail. Changing directions and dimensions are also significant problems. This book looks to the distant future and make assumptions that are reasonable but not guaranteed. The most significant assumption is the existence of a fifth force - a baryonic force - that makes travel out of our universe possible and plays a major role in travels in the multiverse. This assumption is supported by theoretical evidence - the conservation of baryon number. The second most significant assumption is the existence of the multiverse of universes. The existence of other universes and thus a multiverse is supported by the need for a mass for the Higgs Mechanism, the need for a quantum observer, and the need for a clock for the universe. The likelihood of these assumptions, and the novel, new perspectives they lead to, caused the author to proceed to explore the possibilities of emerging from our universe and traveling to other universes knowing that it would not be feasible for many tens of thousands of years. After Man has explored the stars, has explored the galaxies of our universe, there will still be the quest to explore the many universes of the Cosmos: to see eternity's sunrise, to reach the heights and depths of fundamental Reality, and so to grow to maturity as a species. This book is not a science fiction book but rather a reasonable extrapolation of current science and technology.