Customer Reviews

Centauri Dreams: Imagining and Planning Interstellar Exploration

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It will be surprising to many people that the initial planning of humanity's first voyages to the stars has already begun. Those of us who grew up in the early days of the American space program, and whose vision of the future assumed that by the end of the twentieth century space flight would be commonplace and relatively easy, and who assumed that manned missions to Mars and further would be the next step within several years after the Apollo moon landings, became impatient with the slow and methodical pace of space exploration carried out in the immediate vicinity of Earth and by robotic probes sent about the Solar System- even though these missions were usually brilliantly planned and executed.

This book brings the welcome news and consolation that, even though the first interstellar mission of any kind is probably still at least several decades away, imaginative and intelligent people are already working on the theoretical basis for such future voyages, and some of the engineering problems are being addressed. So at least we don't have to wait until the rest of the solar system has been explored to get an idea of how the next colossal task will be approached. Much of this work is being done by various research agencies associated with NASA, by the European Space Agency, and even by academics and assorted dreamers.

Paul Gilster does an excellent job of explaining the current state of the planning for adventures to the closest stars, providing lucid descriptions of the work even now being done on such amazing concepts as laser-powered sails and antimatter drives. I have read a fair number of the popular scientific works intended to introduce laymen to difficult subjects (string theory, hyperinflation, etc.), and this volume is at least as clear and readable as anything I have seen by Allan Guth or Brian Greene. Besides being a primer, however, Centauri Dreams is also a fine piece of investigative reporting, since the author discusses the people who are doing this imaginative work and places their endeavors within an institutional context to show some of the bureaucratic and political hurdles that must be overcome.

Mr. Gilster also relates interstellar planning to the development of notions of interstellar travel within science fiction, showing how fictional (and often very much misguided) thought has influenced scientific thought.

Centauri Dreams is an exciting and important read. Highly recommended.

This book is about sending a space mission to a nearby star. I know, it sounds more like science fiction than fact. We're talking about really long missions. Perhaps several hundred years or even a couple of thousand years. Even the one-way light time to our objective would be on the order of five or ten light years.

Gilster starts by mentioning some possible destinations: Alpha Centauri (closest, at 4.3 light years) and Epsilon Eridani (10.7 light years but may be more interesting biologically). Or possibly Barnard's star (5.9 light years) or even Tau Ceti (11.9 light years).

Yes, we could try to get a spacecraft to move much faster. But that's not easy. And there's a much, much higher chance for the spacecraft to be destroyed just by hitting a very small object. The author warns us that at such speeds, a grain of sand would look like a torpedo. Even if one of the speculative propulsion technologies the author then discusses could be made to work, the chance of the spacecraft surviving the trip might be rather small.

On the other hand, the author also tells us about space telescopes that will be looking for terrestrial planets in the next few years. What if one of them finds a planet that looks like it harbors life? Would we then start taking a mission to that planet seriously?

Still, how does one get there? Gilster explains that chemical rockets are unlikely to be the right answer. Even nuclear propulsion is too weak. The first alternative he suggests is antimatter. With all due respect, I find this idea preposterous. The next idea is a Laser Accelerated Plasma Propulsion System (LAPPS). While this idea might work in theory, present technology is several orders of magnitude short of being usable.

Next we get a technology that come a little closer: solar sails. The author discusses a 249 x 249 foot sail that is being built by L'Garde, a California corporation, that can take a 3-kilogram payload out of the solar system. It would take this sail 100,000 years to get to Alpha Centauri, which shows that with today's technology, we are about two orders of magnitude short of what we need for such a mission to make any sense. The author explains that with expected improvements in technology, we're likely to get one of those factor-of-ten improvements. But the next one will not be so easy. Nevertheless, this is the least speculative of the ideas presented in the book.

Gilster also tells of another (but more speculative) idea that might give us a similar speed, namely Mini-Magnetospheric Plasma Propulsion (M2P2), which is advocated by Robert Winglee at the University of Washington. This involves creating a "magnetic sail" kilometers in diameter which would hitch a ride on the solar wind. This idea needs much more work than a normal solar sail, but I think it is worth pursuing.

After this, we see a technology that would supply enough speed to our spacecraft if it worked: a laser-beam driven sail. All we need is 65 trillion watts of power on the ground! Plus the technology to deliver it to the spacecraft sail. And then get the craft to survive the flight. I guess all this is worth investigating, but this technology is nowhere near where it needs to be so far. At best it seems impossibly expensive.

The final portion of the book deals with some obvious problems: how do we communicate with the spacecraft when it is so far away? How will spacecraft navigation work? Or power? And best of all, how will the spacecraft maintain itself? What sorts of AI algorithms will need to be developed?

I found this book very interesting, but it does appear that it will be a long while before we have a successful mission to another star.

A well researched book that takes a realistic look at how we might one day explore the nearest stars. And this is a very big
dream indeed. The problems with making such a mission work are daunting. But the book doesn`t dive into science fiction, at
least not much.
The book takes a realistic look at not only the possible systems that could send a probe on an interstellar mission, but at the
massive problems that must be solved. The truely mind boggling distance to the nearest star is only the most obvious of these
problems.

i just finished this book, and i have to say, it is one of the better books on this subject i have read. if youve read Zubrins entering space, and/or the case for mars then you are probably familiar with most of the concepts in this book, but if you are into realistic visions of mankinds future in space i would HIGHLY recommend this book, it makes me feel like a kid again, watching the first shuttle launch and thinking (if we can do this, there is nothing we cant do!) the title of this book sums it up well, if you want to rekindle the feeling of endless possibilities for the future, read this book and dream the dream.

I like that I have finally found a book that discusses interstellar travel in serious, but very readable way. It isn't too heavy on jargon, but gives you just enough to not make you feel like the book was dumbed down. I highly recommend this book as a purchase. The only reason I gave it 4 stars instead of 5 is I have some quibbles on the pacing and structure of the book. Chapters sometimes seem to end abruptly with no warning, and he occassionally gets a bit too chatty, but these are minor quibbles.

Centauri Dreams was a fun book for the futurist some time ago. The book enables the reader to let go into the future and think about interstellar space travel. The book is well structured and enlightening to the non-scientist and non-engineer. The technologies the author discusses are being researched but the practical applications will be years, decades, perhaps centuries, into the future for travel outside of the solar system --- even if we do now have a structured human effort to find an Earth-like planets outside of our solar system. The book has an associated blog that is fun too and has caused me to reflect upon the book from time-to-time. I recommend the book if you want to sit back and think about how your great-great grand children will cross the Milky Way Galaxy with a dash of realism and a dash of science fiction. Every great adventure begins with a map. This book is a creative map into the future of space travel.

I was hoping this book would be a technical discussion about robotic interstellar travel. I was disappointed to discover that it was largely a non-technical series of interviews of people working in the fields of interstellar space flight. I was hoping to get a real understanding of the energy required to attain relativistic velocities but I was disappointed. I also wanted to learn a lot more about ion propulsion but this was only lightly touched on. There was not a single illustration or graph in this book. I also did not follow the logic of the topics covered; it was as if the author just assembled chapters based on the people he was able to get interviews with.

How long would it take the space shuttle to go one light-year? The shuttle orbits the Earth at about 5 miles per second (18,000 mph). Light travels at 186,000 miles per second, which is about 37,200 times faster than the shuttle. So the shuttle would need about 37,200 years to go one light-year.

Proxima Centauri is 4.2 light years away = 156,240 travel years. So, how much faster would a "space ship" need to travel to get to PC in a day?

Gilster did an excellent job researching and describing various methods of interstellar propulsion, communications and AI. Life support systems got relatively little space because the book is mostly (although not entirely) about unmanned interstellar probes rather than manned starships. However, I found one omission very jarring -- total absence of any consideration of increasing human lifespan.

There are two ways to get some place very far during one's lifetime: 1) go very fast; 2) live a very long time. Gilster points out that a multi-decade (let alone a multi-century) interstellar probe will by necessity be a relay effort, with younger researchers inheriting the project from the older ones. He also laments the modern society's short attention span and calls for resurrection of midaeval outlook, when many generations would spend their entire lifetimes on projects like cathedrals. He does not seem to realize that this problem can be solved by a fairly modest increases in human lifespan, while true defeat of aging would make interstellar travel possible with TODAY's technology (almost).

And like it or not, the amount of research currently put into geriatrics, biotechnology and life extension is enormous, absolutely dwarfing the research into advanced propulsion, or even all space technologies put together. I would bet more than even money that by the time it will be possible to send a probe to the nearest star at 2% the speed of light (200 year trip), people sending the probe on its way will expect to still be around when it arrives to its destination. And incidentally, that would take care of Gilster's other lament -- lack of long-term thinking. For someone who truly does not age can't afford NOT to think in long term. If ice caps are going to melt in 100 years, if an asteroid will hit Earth in a millenium, if Sun blows up into red giant in 5,000,000,000 years, it all becomes MY problem, and I have to do something about it. That is truly unprecedented in human history, and must be taken into account by anyone who seriously considers the future.

What we have here is a reporter that is surveying what many scientist and engineers are planning for a spaceship to the closest stars based on current technology.

If your interested in this subject, don't want any mathematics or diagrams and don't want to get much into theory but have the reassurance that this is at least theoretical real and not fiction then this book is for you.