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ÑóẊîöʼn
8th December 2010, 21:01
Rather than massively derail this thread (http://www.revleft.com/vb/why-hatred-anarcho-p1950654/index.html#post1950654), I thought I would continue a conversation in it's own thread.


Carl Sagan has suggested a novel use for nuclear bombs that are just laying around: spaceship propulsion. We could get to Mars in a couple weeks with a nuclear-powered spaceship.

The idea of using nuclear explosives as a form of spacecraft propulsion actually dates back further than that; Project Orion (http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29) started in 1958 based on an idea proposed by Stanisław Ulam in 1947. A handful of variants were proposed, and the design can still be modified to suit modern sensibilities and knowledge - certainly a nuclear ground launch seems out of the question for the forseeable future. Instead of using fission pulse units for the initial takeoff, it may be possible to use nuclear thermal rocket (http://en.wikipedia.org/wiki/Nuclear_Thermal_Rocket) boosters to gain orbit and, if necessary, boost the vehicle above the Van Allen belts before engaging any fission pulse units. Of course, that increases the material and energetic cost of the spacecraft as a whole. But the great thing about the Orion design is that its massive performance envelope enables that kind of flexibility.

Also, getting to Mars within a couple of weeks is nice... if all you want is a latter-day re-enactment of the Apollo saga. While it provided invaluable scientific data, it is hardly the model for a future colonisation and development of the Solar System, with a view to enriching Earth and establishing a permanent and economically self-sufficient human presence off of Earth.

No, the kind of mission that a design such as Orion deserves would involve something along the lines of retrieving a nickel-iron Near Earth Object, preferably the largest one we can find and drag back to Earth orbit, and using the facilities on board the Orion spacecraft (I'm assuming that it's the 8 million ton version) to stripmine the asteroid and process the materials into an orbital infrastructure capable of constructing another spacecraft of similar size to the original.

From then on, our options are opened up enormously. With the original 8-million-ton Orion vehicle plus the dedicated interplanetary spacecraft constructed in the new facilities in Earth orbit, we could make a good shake of colonising Mars for good. Or we could construct a fleet of solar power satellites and have more energy than we could have ever dreamed of if we'd stayed on the surface. Or maybe we could start getting serious about space stations and start work on an O'Neill-style space habitat. Or we could build titanic solar-powered particle accelerators on the Moon designed not for research, but for churning out antimatter, black holes, strangelets and other physics exotica in industrial quantities - if we're feeling ambitious, we could forget the Moon and just do it on Mercury, with it's greater surface area and more powerful insolation.

Given time and the relatively small initial investment of labour and materials, all of those things could be done - and the human species would be immensely enriched, not only materially but culturally as well, with spaceborne communities each providing their own unique perspective on the human (or perhaps by this time, transhuman) condition. With a genuinely accessible Solar System, people may be inspired to establish their own communities independant of the space programme that enabled them to do so - and who knows what they might come up with?

Lord Testicles
8th December 2010, 21:10
certainly a nuclear ground launch seems out of the question for the forseeable future. Instead of using fission pulse units for the initial takeoff, it may be possible to use nuclear thermal rocket (http://en.wikipedia.org/wiki/Nuclear_Thermal_Rocket) boosters to gain orbit and, if necessary, boost the vehicle above the Van Allen belts before engaging any fission pulse units.

What about this idea:


I call it the Verne gun because frankly, a name like THE ATOMIC CANNON would just not go over well in certain circles. In any case, the principle is the same as Verne's original idea, but using modern technology: you set off a nuclear charge underground where the blast, heat, radiation and fallout can all be contained, and use Orion-type technology to direct its energy into orbiting a very big, very heavy spacecraft. This vessel would experience hundreds to thousands of g's of acceleration--you couldn't put humans in it. But Wang calculates that a 10 megaton bomb could put 280,000 tons into orbit with zero radiation escape into the biosphere. http://www.kschroeder.com/weblog/archive/2009/03/04/the-verne-gun
http://nextbigfuture.com/2010/03/150-kiloton-nuclear-verne-gun.html

(http://www.kschroeder.com/weblog/archive/2009/03/04/the-verne-gun)

ÑóẊîöʼn
8th December 2010, 21:25
What about this idea:


http://nextbigfuture.com/2010/03/150-kiloton-nuclear-verne-gun.html
http://www.kschroeder.com/weblog/archive/2009/03/04/the-verne-gun
(http://www.kschroeder.com/weblog/archive/2009/03/04/the-verne-gun)

It's no good for the sort of thing I outlined in the OP - the intention being that the initial launch vehicle would be crewed, since I'm not assuming crazy advances in robotics and AI. Although of course, if such advances were to happen, the Atomic Cannon (I like that name) would look like an inviting prospect, especially if the robots/AIs in question could be made durable enough to survive the g-forces.

In fact, I would not be surprised if a self-improving AI took such a route off the planet if it did not calculate that exterminating us, working with us or ignoring us was worthwhile.

Lord Testicles
8th December 2010, 21:39
It's no good for the sort of thing I outlined in the OP - the intention being that the initial launch vehicle would be crewed, since I'm not assuming crazy advances in robotics and AI.

Could you not send them up separately, assuming that it's cheaper to put a couple of humans into orbit as opposed to something that weighs 8 tonnes. Although maybe I'm just looking for an excuse to set off a 10 megaton bomb. :unsure:

ÑóẊîöʼn
8th December 2010, 22:32
Could you not send them up separately, assuming that it's cheaper to put a couple of humans into orbit as opposed to something that weighs 8 tonnes. Although maybe I'm just looking for an excuse to set off a 10 megaton bomb. :unsure:

It's actually cheaper in terms of cost per kilo to send up a single 8 million (not eight) ton spacecraft into orbit using multiple (re-usable) NTR boosters than it is to try and lift the same gross weight into orbit using chemical rockets, which have an awful lot of disposable parts.

Of course, it's best in terms of efficiency to use the fission pulse units to achieve orbit, but that has numerous environmental complications. For the original design the Orion spacecraft would do a nuclear lift-off using fission pulses from Jackass Flats, Nevada, but that was back when artificial satellites were really new.

But if you really must use fission pulses to launch, a better launch site these days would be somewhere in Antarctica, the Pacific Ocean, the middle of the Sahara Desert, or the Arctic Ocean. This would provide the space necessary so that only mild EMP shielding would be needed for facilities relatively close to the site, with the rest of the world protected by the atmosphere and the curvature of the Earth. Take-off would be from a (floating, if necessary) steel platform, coated in graphite to minimise fallout.

JacobVardy
28th December 2010, 05:37
What about using an Orion craft, and captured asteroid to build a space elevator? Is this in any way feasible?

Nial Fossjet
28th December 2010, 22:30
Project Orion is not feasible at all. There's a lot of technical explanations for why.

ÑóẊîöʼn
29th December 2010, 18:25
Project Orion is not feasible at all. There's a lot of technical explanations for why.

Would you care to point us to them?

Rooster
14th January 2011, 21:40
This is what annoys me. When I was a kid I was expecting to be living on the moon by now!

And surely a land based mass accelerator would be more efficient for sending up to space the materials to build an Orion space craft, instead of just a land based nuclear take off.

Rafiq
14th January 2011, 22:42
Sadly, I don't think we has humans will ever make it past Jupiter... Jupiter that is... if we are lucky.

ÑóẊîöʼn
15th January 2011, 07:19
And surely a land based mass accelerator would be more efficient for sending up to space the materials to build an Orion space craft, instead of just a land based nuclear take off.

Not at all. Because in the first instance, anything launched from a mass driver would only be accelerating for the brief period that it is in the armature. Then, once you have launched the materials (and smashed to pieces anything remotely fragile that you were foolish enough to submit to extreme acceleration) you have to have to assemble the materials into a spacecraft - not the easiest thing in the world to do when you have next to no industrial infrastructure whatsoever in space.

That's the whole point of building the thing on the ground before launching it - we currently have no industrial presence in space, but an 8 million ton spacecraft with a sizeable amount of such facilities already on board would be a huge boon if it were to be launched.


Sadly, I don't think we has humans will ever make it past Jupiter... Jupiter that is... if we are lucky.

Actually, if you look it in terms of energy expenditure, achieving a stable orbit means you are half-way to anywhere else. Lowering the cost of going into orbit is key.