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Project Orion: The True Story of the Atomic Spaceship
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.
I read this book a few months ago and I agree with the reviewer that this is an excellent book. However, it tends to concentrate a great deal more on the politics surrounding Project Orion than the science much to my chagrin. Much of the information surrounding Project Orion is still classified so I don't necessarily blame the author for this, but those intending on reading the book should qualify their expectations.
I did get a great appreciation for the sheer size and magnitude of truly difficult engineering problems and the organizations and minds assigned to solving them.
All in all, it's a quick and easy interesting read that engineers and NASA junkies will likely enjoy.
If you are ever in Idaho, you should visit EBR-1, the world's first breeder reactor. It is decommissioned, cold, and open for tourists during the summer season. Outside, they have some prototype nuclear jet engines - devices that took in air, heated it with a fission reactor, and expelled it for thrust. Neat stuff - would have been nasty as hell had it ever gone into service, but neat none the less.
EBR-1 is about 4 hours drive from the west entrance of Yellowstone National Park, and about 45 minute from Craters of the Moon National Park, so there's plenty of other stuff to do in the area.
www.eFax.com are spammers
Another good book that bears on this subject is Robert Zubrin's Entering Space: Creating a Spacefaring Civilization. He discusses the atomic bomb drive as well as other postulated ideas for interstellar craft, such as solar wings and some trick with laser and mirrors (IIRC).
Even better, for slashdot folks, is that Zubrin takes this stuff seriously in a scientific sense. He discusses the energy needs and expected capabilities of the various craft, and in general covers a lot of "practical" ground. This is the same guy who is behind The Mars Society, which actively works to enable and encourage mannned missions to Mars.
Slashdot has covered Zubrin and Mars Society before; see this and that. He also has a mars-specific book titled The Case for Mars: The Plan to Settle the Red Planet and Why We Must. I recommend both his books to anyone who thinks we need to get off this rock.
Feasable nuclear engineering: 500 billion
Buncha rocket scientists: 10 millon
Building the engine: 1 billion
Putting Manhattan into orbit:Priceless.
All Troll + "offtopic" mods are meta moderated as "Unfair", because you abused the system.
The shielding burns up, but at a predicted rate, and it lasts long enough to get the craft on the ground. Shuttle shielding is the opposite, it's a ceramic that simply "holds" the heat (vast simplification there, but well).
And it's ablation again with Orion. Sure, the explosions ablate part of the shielding, but it lasts long enough to get the craft where you want it to be.
And to answer your other question, the idea is like the engine of a car. If you can hear the individual pistons firing, then you've probably got a problem! But they do fire individually. Same thing with Orion (or similar) - the bombs are chucked out the back at a pretty rapid rate. At least in the designs I remember - I haven't read the book but I will based on the review. It sounds fascinating!
This is a design by Robert Zubrin for a rocket that produces a continous atomic blast using water with a high concentration of Uranium or Plutonium salts.
Nuke Your Way to the Stars
Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.
You can find more info about advanced propulsion techniques (like the Orion-project) and other interesting space-science stuff at Warp Drive When?.
Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
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.
"To Do Is To Be" - Socrates, "To Be Is To Do" - Sartre, "Do Be Do Be Do" - Sinatra
Cool hack if ever I have seen one! Build-your-own Mars Base in one of the most Mars-Like places on Earth, and do real research on how to operate said base when (not if) we get to Mars.
If you keep up with the web traffic on this project, NASA's position seems to be basically "Great work guys!" and "Can we send our best people?" to which request the Mars Society seems to graciously and intelligently accede.
It's attitudes like this that explain why my children won't have mutant powers.
Keep in mind that all controlled, sustained nuclear reactions we have engineered to date are fission reactions. An inefficiently converted but uncontrolled fusion reaction (aka Hydrogen bomb) will still give more "bang for the buck," literally and figuratively.
taken! (by Davidleeroth) Thanks Bingo Foo!
It's been done. Short story, in the 1950's they were still testing nuclear weapons. They put one at the bottom of a long mine shaft and put a heavy metal plate on top to partially contain the explosion. The plate was last seen moving at about six times escape velocity.
On the other hand, it probably vaporized before leaving the atmosphere, see Operation Plumbob for more information.
For more on Ted Taylor -- his work on fission bombs, his participation in Project Orion, his speculations on how small a nuclear bomb could topple the World Trade Center towers (decades ago), and his concerns about nuclear proliferation -- I strongly recommend John McPhee's The Curve of Binding Energy (BN). McPhee (BN) is an excellent writer, and this is one of his books I enjoyed the most.
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The interview is great for conveying the commitment and enthusiasm Freeman felt for the Orion Project. They really believed that the ship would be build and flown to Mars last century. With NASA's new administrator Sean O'Keefe talking about alternative propulsion systems (including nuclear), who knows maybe Dyson's ideas will actually see the light of day.
yea i stole your sig- whats the big deal, it sucked anyway.
I remember reading an interview with Freeman Dyson a couple years ago in wired. He mentioned a week he visited his Daughter, Esther, at Harvard. During the time, she never attended a single class.
When he asked her about it, she said something like "you don't go to Harvard to study, you go to meet people."
It's interesting that she was one of the fist heads of ICANN.
autopr0n is like, down and stuff.
First, the starting point of Orion was asking the question, "How do we get multi-ton payloads into space?". Chemical rockets, then and today, take tremendous amounts of resources to get a few hundred kg into space. Then and now, that doesn't really do much for anyone.
Second, you have to remember that the Orion project started during the era of above-ground nuclear testing. Yes, an Orion launch would have created some fallout and upper-atmosphere contamination. But compared to the 10 MT (US) and 60 MT (USSR) monsters that were being fired for test purposes, the pollution wouldn't have seemed so bad.
Of course, times have changed, and I doubt anything like this will be ever be used in the atmosphere except in dire circumstances (Footfall, Deep Impact).
sPh
Way I see it there are three approaches to nuclear propulsion: 1) Orion -- putty-putty bang-bang, 2) NERVA -- high power density reactor which heats up hydrogen that squirts out a conventional rocket nozzle, and 3) VASIMIR (Variable specific impulse magnetic rocket) -- use the nuclear reactor for an electric power station and accelerate hydrogen or other gas with a magnetic rocket nozzle (there is also ion drive, but VASIMIR is popular these days because it offers the greatest thrust of all the electric schemes). The book, in talking the politics, indicated that NASA Huntsville though that Orion was pie-in-the-sky before doing something like NERVA first. VASIMIR is a more recent proposal and was not under consideration in that era. My understanding is that NERVA would be a replacement 3rd stage to a Saturn V -- that way the reactor would not be turned on until you got into space. One thing about NERVA is that its propellant is stores as liquid hydrogen, which is one of the bulkiest, least dense liquids around. The NERVA stage would have been huge, essentially the same diameter as the S-IC and S-II rocket stages below it, making the nuclear Saturn V one continuous cylinder until you got to the payload fairing. Given the weight of the reactor and given the bulk of the hydrogen tank, I am wondering if the 800-second specific impulse compared to the 430-second specific impulse of the regular Saturn S-IVB upper stage would have been a wash. Orion had a bulk problem too. If it was ground launched, if could have had a much bigger diameter pusher plate to capture more of the nuclear explosion and be more efficient (or perhaps less inefficient). Its efficiency came from the ultra-high temps of a nuclear blast compared to a sustained nuclear reactor and its inefficiency came from most of that efficiency being wasted apart from the little bit captured by the pusher plate, and the bigger the pusher plate the better. I thought they said a ground launch Orion could be in the 10000-second specific impulse range while the Orion launched as a third stage of a Saturn V was reduced to about 2000-second specific impulse because of the smaller pusher plate -- you start getting into the is it worth the bother range. I actually think that the Orion approach would be by far the easiest from the engineering standpoint, given how much work and testing went into bomb making. The only holdup is the idea of polluting even space let alone the Earth with that much fission fragments.
Just briefly I had the opportunity to meet George Dyson (a really nice down to earth guy). If the name sounds at all familiar, his sister is Ester Dyson (used to be chairperson of ICANN) and father is Freeman Dyson (a well known theoretical physicist). From what I've heard, George was always the odd one out in the family taking his own path. He used to live in a great looking tree house on the north end of Vancouver Island and then went on to research and build baidarkas (an Aleut Kayak).He has a great book on the kayaks called "Baidarka" which in the first half covers the history of the their development and Aleuts interaction with Russian traders and then moves on to cover the vessels themselves and his work.
He then went on to research and write a book on A.I. titled "Darwin Among the Machines: The Evolution of Global Intelligence". In addition to the original theories about using nuclear explosions to propel space ships, his father had the concept of building a huge structure around a star that people would live on the inside of and the star would provide the energy. You may remember this from a Star Trek Next Generation where they brought back Scotty, it was the Dyson Sphere. A final interesting tidbit is that George Dyson's grandfather Sir George Dyson was an English composer and founder of the National Federation of Music Societies.
Overall, it's an interesting family with some incredible minds in it. The BBC has a short piece on his AI book and on the left hand column is a real audio interview with George. There are also plenty of other links on google if you plug in his name.
The reason that a rocket engine has a conical 'bell' is to control the behavior of the exhaust gases. Specifically, the shape of the exhaust bell controls the efficiency of the gas flow, and prevents losses which could reduce thrust. All of the exploding happens inside the rocket, and it is the escaping gasses which the exhaust bell is designed to affect.
FYI, one of the main uses of explosion control is shaped charges, the kind that police special units use to get through walls/roofs/ceilings. A simple shaped charge can be made by placing two explosives in a 'V' shape, the resulting explosion will be pointed toward the opening in the 'V'. It's not magic, the explosion is very radial, but more heads toward the open end of the 'V' than any other direction. To get a charge which points most (nearly all?) of the explosion in one direction, put something strong and heavy around the explosive where you don't want damage. Example - a piece of angle iron (an 'L' shape of steel) with strips of C4 along the inside of the 'V' will shape the explosion and direct it toward the open end. Unfortunately, Newton's Third Law still applies (for every action there is an equal and opposite reaction), so the force of the explosion will want to move the angle iron. So you weight it down with sandbags. This is pretty much how LAPD started using shaped charges to enter buildings through the roof. A few pieces of angle iron with explosive in them, some sandbags, arrange on the roof, get behind something and BOOM. This was later refined - the shaped charges (iron pieces, wiring, & everything) were attached to a piece of particle board, placed on the roof, a few sandbags were dropped on top, and you could create yourself a nice entry hole for your SWAT team in a few seconds.
Caveat: I haven't experimented with shaped charges, I've just read about them.
sPh