Geodesic,
A design, an outline proposal, some detail on exactly how this works.
When Kennedy proposed going to the moon within ten years, he wasn't asked for a detailed plan. A pity you weren't there to do so. I never liked the hole through the pusher plate model as it weakens the structural integrity of the plate. There is also the problem of rapidly firing pulse units in succession which while attainable would make the delivery system overly complex. I prefer the around the pusher plate model where many delivery points become exposed at the apex of shock absorber compression and take turns firing them off like a gatling gun. Each device detonating as the plate has come down and is protecting the delivery openings. The shock absorbers would be low pressure gas bags. This is the simplest and most effective system. To eliminate the risk of dud bombs throwing the system out of rhythm the bombs could be delivered 2 at a time. I'm working on some schematics now. I'm not an engineer and a serious design study for this fusion Orion would best incorporate an environmental impact study.
If you are serious about wanting to learn more about the Orion drive and its possibilities then here is a list of sources available on the net.
Orion Links.
Phlog,
It's unspoiled. Not wasteland.
An unspoiled wasteland then. Like the moon. We'll just have to agree to disagree on the value of pristine frozen tundra of no use to anybody or anything except a few astronomers and coastal penguins. We used to blow up bombs in Nevada and people walk around the place today. We are talking about a one and a half mile blast radius on a continent the size of the United States. Your concerns are laughable.
There's not much that benefits mankind that needs producing in space in any great volume, so this point is invalid.
Are you an isolationist by any chance? Your lack of vision is extraordinary.
There's no need, we are stood on a massive resource already.
Not massive enough if we want to grow. Increased technology requires increasing population. Advanced tech requires large numbers of specialised scientists. The only alternative to expansion is decline. Stagnation is death.
Q,
Unfortunately, that is all that ProjectOrion is capable of providing.
What have you provided in this debate Q? Apart from snide remarks.
Geodesic,
Oh, another point that ProjectOrion seems to have missed - his proposed launch method is illegal under international law.
Its an international proposal. Laws are reflective of public opinion but slow to change. The issue of law only arises when the question of launch is handed over to the masses. Should the public approve of conquering space in this fashion then the law can be ammended. No big deal. The ship itself can still be built. I have always maintained that a launch should be decided by the people. That necessitates an informed public and the first step in achieving that is steady consistent propaganda.
Truthseeker,
Funny that you say that. Because I've been reading some stuff in some magazine, and they say that they already have enough technology to make it efficient.
Fusion reactors again. The great hope of the 21st century. Not to mention the earlier 20th century and no doubt likely to continue the trend into the 22nd century.
Just like fission, fusion offers both pulsed explosions and (atleast theoretically) steady burn options for rocket propulsion. With higher enthalpy and more plentiful fuel it's obvious that both of these are more practical than fission.
Hydrogen explosions were realised an attainabler goal atleast three years before the first fission bomb was even detonated. Even earlier H.G. Wells wrote about them. It was recognised that fission would produce, for an instant, temperatures and pressures more extreme than those within the interior of the sun. If suitable nuclear fuel were subjected to this then a very small sun might be brought into existance. One which in the next instant, without the gravity that holds the sun together, would blow itself apart. Splitting the nuclei of heavy elements like uranium or plutonium releases tremendous energy but fusing the nuclei of deuterium (the cheapest fuel on earth) can release a thousand times as much energy.
Stanislaw Ulam invented the first successful device after Teller's model failed. Ulam incidentally was the originator of the Orion concept. A genius with few parallels. 'Ivy Mike' was detonated on November 1st 1952 at Eniwetok Atoll in the South Pacific. An 82 ton tank of deuterium ignited by a TX-5 fission bomb. Equivalent to about 1000 Hiroshima's.
Over half a century later we still cannot cause hydrogen nuclei to fuse into helium nuclei for use as a power source. We are at best able to achieve 25% of the parameters necessary for the simplest sustained fusion reaction. Fusion reactors or what I like to term 'fantasy engines' would require 500 million degree's to work. State of the art in magnetic confinement has only reached breakeven point. The plasma density and average particle confinement time in our very best deuterium-tritium reactors now allow us to get back as much energy as we put into the system!
After all these decades it is unreasonable to expect that further incremental gains will accelerate. Instead they will steadily decline annually as we futilely attempt to squeeze more and more efficiency out of the technology. Just as chemical rocket technology gains similarly decrease each year.
The race is not always to the swift nor the battle to the strong, but that's the way to bet. Orion may be crude but its also rugged and flexible. Ideal for pioneering space. An Orion using hydrogen bombs would achieve much higher performance, use far cheaper fuel, have greater payload capacity and would produce a cleaner exhaust compared to a fission driven version.
Steady fusion is a pipedream. I wish it wasn't so. It would be nice to see fusion reactors solve earths energy problems and open up the solar system. I would be its strongest supporter. Despite the fact that a waste product would be tritium (useful for nuclear weapons manufacture) and the reactor walls would become radioactive over time necessitating periodic burial and replacement.
A bell nozzle as used in chemical rocket engines is 94% efficient. A magnetic nozzle for a steady fusion drive might be around 60%. That's a lot better than Orion's 25% so steady fusion looks very attractive. Unfortunately it's like anti-gravity, wormholes and hyperspace. Fun to talk about but not much more than mental masturbation at this point.
I'm pragmatic. I prefer engineering which is challenging but realistic. Right now we are caught in a vicious circle. We don't see companies rushing to build affordable launch vehicles because there is no demand. There is no demand because there is little in space except satellites and a half complete ISS. The reason we don't have much up there is because it costs too much to launch anything. So around and around we go. We have to break the cycle.
An Orion massing 100 thousand tons with nearly equivalent payload would change everything. Early explorers crossed the oceans because there was something to reach. Orion, by industrialising space would give us bases to reach. An incentive to stage regular launches to orbit. Regular flights would bring down costs and competition would cement the new cycle of rapidly diminishing costs. Once in orbit we are halfway to anywhere. Space industries such as the construction of interplanetary ferries would make the solar system available to the common man and woman.
Life is not about avoiding all risks. Quite the opposite. Nothing worthwhile is ever gained without risk. In this instance the risks and dangers are negligibler and the rewards infinitely priceless. One launch far from any living ecosystem and utilising all the innovative methods we can think up to reduce residual radiation would herald a new Golden age of exploration and expansionism.
slotty,
Launching from the Antarctic would have a massive effect on payload. All of the worlds launch centres are located as close to the equator as possible, as this aids a rockets launch to the east.
It isn't a significant gain. Extremely worthwhile for big dumb chemical boosters but not important for a fusion Orion as it creates a lot more thrust. This type of single stage to orbit vehicle doesn't even need an orbital trajectory.
Also given that you want to detonate nukes to propel this spacecraft, what would you do about G forces?
Shock absorbers. Extremely large ones. For a 10 thousand ton model they would be around 4 stories high. So for a 100,000 model 40 stories. It would be like riding a pogo stick during boost phase.
and what would be used to shield the crew from radiation?
The plate and and lower decks would provide enough shielding for anything over 10 thousand tons. Only the smaller vehicles proposed by Nasa would have required extra shielding. Such a small Orion would have been far less efficient. Partly because of the extra shielding mass.
Phlog,
Try not to laugh too much
Small minds are often easily amused. Rather unimaginative dullards snickered at the first cars too. Submarines and armoured military vehicles were a standard joke for awhile. As were hunting rifles for warfare rather than using useless muskets. Edison's electric lightbulb experiments were the target of much uproarious laughter.
Ofcourse the biggest laughingstock around is Nasa and it's giant fireworks. I wonder how many more Shuttle pilots will get barbecued before they realise what a joke they are.
No atomic bomb has ever accidentally detonated.
