Project Orion: The True Story of the Atomic Spaceship

Johnzo writes: "It seems ludicrous to imagine that a spaceship could ascend into orbit and beyond by riding the impulses produced by a series of external atomic explosions. Such an idea would perhaps be more properly confined to science fiction -- like the Niven & Pournelle classic Footfall. But Footfall drew its inspiration from a real-life project, a project that, according to George Dyson's Project Orion: The True Story of the Atomic Spaceship, continues to offer exciting possibilities for space exploration." This sounds like a fascinating book; read on below for johnzo's full review. Project Orion: The True Story of the Atomic Spaceship author George Dyson pages 345 publisher Henry Holt & Company rating 9/10 reviewer johnzo ISBN 0805059857 summary An excellent high-level introduction to the characters, engineering, culture, and future of the Orion project, and an ideal jumpoff point to other readings about the atomic age.

The chief advantage of an Orion-style spaceship can be explained in terms of specific impulse, which is the time during which a mass of fuel will produce enough mass x g thrust. Conventional chemical rockets, constrained by exhaust temperature, can produce specific impulses of about 430 seconds. Orion-style engines promised a specific impulse that was an order of magnitude higher than that--"2000 to 3000 seconds for first-generation designs, 4000 to 6000 for larger vehicles using existing bombs." The combination of long specific impulse and high thrust was unique to Orion, and would have allowed for the sustained high-acceleration maneuvers necessary for long-range manned space flight. And, like nuclear bombs in general, Orion scaled up more easily than it scaled down. The original Orion reference design massed 4,000 tons, and unlike the Apollo missions, which sent 600 lbs into space for every pound that came home, more than half of Orion's launch weight would have returned to Earth from a voyage to Saturn. Had it fulfilled its promises, Orion would have enabled manned space travel on a grand scale, with thousands of tons of payload and year-plus mission durations. It would have let us go into deep space in spaceships instead of mere disposable, unmanned spacecraft.

From 1958 to 1965, a team of physicists and engineers at General Atomic in California pursued the Orion dream. Project Orion tells their story ably. Dyson explores high-minded science and baroque bureaucracies in short, manageable, anecdote-loaded chapters. It's a terrifically easy read; with just freshman physics and a passing knowledge of 1950's America, I was able to follow along with no problems. The book begins by explaining the basics of Orion, the 1950's atomic establishment, the dot-com-like culture at General Atomic, the experiments that gave rise to the Orion idea, and the seed funding from ARPA. Dyson moves on to introduce us to some of Orion's chief characters, notably Stanislaw Ulam, who originally patented the atomic-pulse-drive idea, Ted Taylor, the Orion project leader and namer (he "just picked a name out of the sky," says the book) and Freeman Dyson, the celebrated scientist who was on board for the first two years -- and, who, not coincidentally, is George Dyson's father.

From there, it's on to the fun parts, beginning with the chapters detailing the engineering problems that Orion's designers faced. Most obviously, how do you design a pusher plate that won't shake itself apart or ablate under repeated impacts of nuclear plasma? (answer: with a thin coat of oil, reapplied between each atomic pulse.) How do you cushion the crew from the hundred-g shock of the pulse-unit explosions? (answer: with two-stage shock absorbers.) How do you shape the expansion of the propellant plasma so that you hit the pusher plate right? (answer: you take advantage of directed-energy weapons research to shape your atomic charges.) How do you eject your atomic charges from around the rim and orient them so that they explode correctly? (answer: you talk to Coca-Cola about bottling plant design.) And how do you cope with a pulse-unit misfire that sprays your pusher plate with jagged shrapnel instead of friendly plasma? (no answer given.)

Since GA's Orion program was a small shop that wasn't straightjacketed by job descriptions, the physicists were free to envision operational details and space missions for their baby. After concluding its engineering coverage, Project Orion looks at some of these missions. Freeman Dyson proposed a mission that would have landed on the moon, orbited Venus, Earth, and Mars, and then gone out to to Enceladus, Saturn's second-innermost satellite. The mission would have made clever use of tricks like planetary gravity boosts, in-atmosphere decelerations, and propellant harvesting to stretch its range. The senior Dyson was vexed by the problem of atomic contamination, though; even if it used the cleanest bombs available in the late fifties, an Orion launch would still introduce considerable amounts of toxic fission products into the Earth's magnetosphere. Dyson estimated that about ten people would die from atomic contamination for every Orion launch. This was about one percent of the estimated fatalities attributed to the atomic tests of the day. Instead of waiting for cleaner bombs to solve this problem, GA collaborated with friendly factions inside NASA--including rocket pioneer Wernher von Braun, who was an enthusiastic supporter of Orion--to discuss rocket-boosted Orion models. Proposals were made to either loft Orion into orbit wholesale or to boost it in pieces and conduct final assembly in orbit. Rocket-powered auxiliaries were also discussed; these would serve as landing craft and inter-Orion taxis.

In the end, of course, all of this work amounted to nothing. For various reasons -- nuclear test bans, lack of funding, and indifferent brass -- the Orion project was never permitted to conduct any of the nuclear test shots necessary to advance its work. The Orion staff made only a single successful test flight during the entire duration of the project, and this was conducted with 1m-diameter model powered by C4 charges. By 1959, Freeman Dyson had left the effort; he had seen that NASA wasn't going to budge away from Von Braun's giant rockets, and he knew that NASA was the only agency that would be able to support Orion. The project staggered on for four more years under Air Force funding, but the Air Force wasn't the right fit for Orion; no one could figure out a clear and present military use for all that lifting power. The USAF repeatedly approached NASA for money, but NASA was interested only in the conservatively incrementing known technologies, not in wholesale revolution. Orion was orphaned by 1965, its knowledge scattered through hundreds of classified documents and dozens of scientist's brains.

The book ends on a fascinating note, with modern-day retrospectives from various Orion staff. Some of them--including Ted Taylor--have renounced the idea of atomic weapons entirely. Some of them are convinced that Orion could never be made to work safely and reliably. Others believe that Orion is an idea whose time will come. NASA agrees with them, in some small measure; they're looking at Orion again as a space-exploration and asteroid-intercept technology. They're having a tough time finding details and data from the General Atomic project, though -- much of Orion's data is still classified. Dyson has had more success in hunting down those documents than NASA. When he contacted them in the course of his research, they begged him for copies!

I greatly enjoyed reading Project Orion. The only disappointment it held for me was its heavy reliance on Freeman Dyson's recollections, and the consequent weighting of the book towards Dyson's year of involvement. I suspect there's a lot of interesting detail missing from the latter six years of the project. That aside, Project Orion is an excellent high-level introduction to the characters, engineering, culture, and future of the Orion project, and an ideal jumpoff point to other readings about the atomic age.

You can purchase Project Orion: The True Story of the Atomic Spaceship from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

Comments

Someone explain this to me please

[Winterblink]

I've heard of the Orion concept before and quite frankly I can't understand how you build something to withstand an atomic explosion for propulsion purposes and not have it blow itself to smithereens. I DO realize that we're not talking about megaton sized explosions here. :) However I'm still fuzzy on how a very low power explosion could keep the damage to the craft down while still providing an effective means of propulsion. Or is this similar to the impulse engines of star trek (the greatest scientific precursor ever, *snicker*), where the nuclear reaction is fed constantly by small amounts of reactive mass?

Nukes for Nasa

[Angus McNitt]

The only question I would have about using Nuclear power for space launch woudl be not only be residual radiation at the launch site, but the weight of the craft itself. Too much weight and it won't lift, too little and you cook the occupants. Even a minimal craft woudl have to be very heavy. I would think re-entry would be very problematic. How do you retard you downward velocity enough not to destroy yourself landing. Make a blast chamber that stayed in space or burned up in atmosphere? Would be a great way to lauch heavy componants to a large space station thouhg.

Also if you had an interuption in the blast progression, what would keep you from falling like the giant lead weight the craft would be? To use the Footfall reference again, wasn't that their major concern after the first one when off; keeping them going at the correct rate? Too little you fall, to fast and you either pulp your occupants or start to damage the "bomb guns". I guess now that part would be safer to test due to computer modeling. You wouldn't have to convert hundreds of tons of Nevada's sand into glass.

Now, if you used it as a space based propulsion, that would be great. It would also help get rid of all those old Russian and American nukes that have been removed due to Anti-Balistic Missle treaties. Also any background radiation would disapate failry quickly.

I'm not a physicist, so feel free to pick holes in this.

We should use Orion as a contingency

[Chairboy]

I'd like to suggest the following: BUILD an Orion ship in the middle of the desert over a period of years. Whenever a big piece of military hardware is decommissioned, install it somewhere on this Orion ship. Sidewinders, old A-10 guns that fire depleted uranium, hell, even ICBMs.

Why? Just in case.

Let's say an asteroid or comet threatens civilization: You'd have a solution that, as messy as it would be, would at least be superior to millions of people getting killed.

What if aliens threaten us? We'd have SOME sort of defense.

What if some unforseeable natural disaster takes place in space and only a big old spaceship will solve it? I'd rather we be prepared then not.

Store is unfueled, keep the nukes where they are now. This way, it's no real threat to anyone. Keep the warheads off the ICBMs it has onboard, all this stuff could be installed in a day or so, if we were properly motivated.

Have schools and colleges build simple re-entry capsules that don't have to be super lightweight.

Put one or two submarine reactors onboard along with a big resevoir of water. Like Niven-Pournelle's Archangel, you could use water for attitude control. For 'precision' maneuvering, you could fire off an ICBM (properly aligned, of course).

This would be neat, and it could be done a LOT cheaper then when you use purpose built components.

Re:Space travel isn't feasible

[Caradoc]

SSTO (or Single Stage to Orbit) vehicles still use chemical fuels - they just use them more efficiently.

I think we're going to see some progress in this field over the next few years, assuming that the American Taxpayers don't start squawking that the money for the space program would be better used to feed people who're too lazy to work.