Incredibly poorly organized. ( )

This book tells the story of one of the most audacious proposals ever to emerge from America's military/industrial complex - the creation of spaceships powered by exploding atom bombs. Improbable though that may sound, the American government expended considerable sums of money and tied up a team of some of the finest minds for a period of seven years, exploring the feasibility of such a proposal and even carrying out a few (non-nuclear) experiments to prove the concept.

The project arose out of the wartime work on the Manhattan Project; after the atomic attacks on Hiroshima and Nagasaki, there were those in the scientific community who were exceptionally conflicted over what they had done. On the one hand, they were deeply engaged in the scientific problems that building atomic bombs posed. On the other, they could not avoid a sense of responsibility for the massive loss of life they had enabled. "The physicists have known sin", said Robert Oppenheimer; and Edward Teller was a vocal proponent of the peaceful uses of nuclear weapons, such as using atomic bombs to speed civil engineering projects. Using such weapons to power a spaceship fell into this category.

There was a side-effect of the proposal. For various technical reasons, the science and technology worked better when the spaceship was bigger. The early proposals for a test vehicle were for something with an all-up weight of 250 tons; the first full-scale prototype would have weighted 4,000 tons and have a diameter of 135 feet. Later plans called for vessels of 10,000 tons - and in those days before atmospheric testing was banned, these ships would be launched from ground level, with a 1.1 kiloton explosion every second.

This was not just a wild idea sketched on the back of an envelope; it was a wild idea that was fully costed, with the engineering worked through and the science fairly well understood (though there remained areas where there were unknowns which the team wanted to explore further in smaller-scale - but fully nuclear - tests). Eventually, though, it became untenable, mainly because of inter-service rivalry (the US Army considered anything nuclear to be their responsibility because it was ordnance, and lived in fear of getting to the Moon to find they had been beaten, not by the Soviets but by the US Air Force; the Air Force considered they should have the project because it involved flying; NASA was set up as a civilian organisation in the middle of this, but were already fairly committed to Wernher von Braun and his chemical rockets, even though the unit cost of lifting a ton of payload using Orion was a fraction - say a hundredth - of the cost of Apollo, and you still had a working spaceship at the end of the mission instead of a twelve-foot bit off the top of the rocket); and increasing concern over nuclear fallout and the various test ban treaties that came into force through the 1960s.

But the idea persists; current thinking about pulsed propulsion systems draws on the Orion concept, even though achieving fusion by targeting deuterium pellets with high energy lasers is at the same time far cleaner and more politically acceptable, though it presents more technical hurdles to leap. The original Orion concept is not dead, however; launching large vehicles from the ground has been replaced by assembling them in high orbit via conventional launches, and then using nuclear explosions to break orbit for a voyage to Mars or beyond. And some of the papers on the Orion project are still classified, mainly those dealing with controlled yield micro-munitions.

The book itself is a bit of a mixture; there are quite detailed technical sections; other parts read a lot like personal memoirs, as George Dyson collected a lot of material via interview. His father, Freeman Dyson, was one of the theoretical physicists recruited to the project from the UK; oddly, the concept Freeman Dyson is best known for nowadays, the Dyson Sphere (a megastructure by means of which an advanced technological civilization can collect the entire energy output of its star; astronomers are debating over whether there are candidate stars currently visible which are having Dyson spheres constructed around them) is not mentioned in the book. The narrative works on a number of levels: there is the story of the project itself; an account of what the scientists from the Manhattan project did next after 1945; a company history of the defence contractor General Atomics, itself a sub-division of General Dynamics; and even elements of local and social history of post-war California. That GA attracted so many of the best minds on the planet to La Jolla must, in some way, have sown the seeds that led to Silicon Valley some thirty years later.

I had heard of Project Orion; but I had always assumed that it was purely a paper proposal. It was not. The USA gave all the signs of being quite prepared to cut metal on this project, making the utopian future of 'Star Trek' at least theoretically possible. There were those who wanted to offer the Soviet Union a place on the project as a gesture of goodwill and a step towards peace. This seems dreadfully naïve now; yet faced with the horror of nuclear war, the scientists reasoned, any attempt to forge goodwill between the superpowers would be worth trying. And the prize? Elon Musk talks today about making the human race into a space-faring civilization by the 2030s; Orion offered this prospect in the 1960s. The team were preparing mission profiles for a journey to the moons of Saturn by 1970; and the technology of a 10,000 ton spaceship offered the first chance for interstellar voyages. An ocean liner-sized spaceship held the prospect of being able to make the trip to Alpha Centauri, 4 light-years away, in 150 years; obviously, well beyond one lifespan, but in a large enough vessel, not impossible on a generational basis. Perhaps, the book closes by asking, Orion is an idea whose time may still yet come. ( )

Excellent retrospective on the attitudes and culture which prevailed in the 1950s - a time of techno-optimism which made even Apollo seem tame. Not particularly well-organized, but it's fairly forgiving if you want to skip through boring sections.

Dyson is quite adept at teasing the audience with tidbits of secret info - both regarding Orion's capabilities (attentive readers will note that he provides all the necessary information to calculate the still-classified standoff distance) and hints of other spinoff projects which may or may not continue to this day.

While the anecdotes surrounding the fascinating cast of researchers who worked on the project sustain the work throughout, the highlights are without a doubt the imagined voyages of the Orion spacecraft. Was a hundred-man expedition to Saturn in the 1970s within America's reach? It certainly was not for the risibly lowballed cost estimates being thrown around in La Jolla.

The conceit of the scientists - not all, by any means, particularly not by the ones who lived through the war in Europe - who believed that simply placing Soviets and Americans together on the same spacecraft would make the public decide that global competition doesn't matter and usher in a new era of world peace. The dream of the techno-optimists was fundamentally an internationalist one, born by the New Atlantis's conquest of the Old World in 1945, the one moment in time when even a materialist might have been forgiven for believing that history might have come to an end. ( )

Nicely written by the son of one of the principals. Seems like the most extreme science fiction, but all true. Every word.

Check mout Freeman Dyson and His son George in the excellent book "The Starship and the Canoe" by Kenneth Brower. ( )

Long book about a project that never happened. Did enjoy the mental challenges of thinking up the project. Probably a little long for a book. ( )