Workable Fusion Starship Proposed 260
Adam Korbitz writes "A former colleague of Edward Teller — father of the hydrogen bomb — has published a new paper proposing a design for what could be the first practical fusion-powered spacecraft (PDF). As described at Centauri Dreams, the design has certain similarities to MagOrion, a 1990s-era proposal for a nuclear-powered spaceship with a magnetic sail and propelled by small-yield fission devices. The proposal's author also has links to the British Interplanetary Society's Project Daedalus, a 1970s proposal for an unmanned fusion-powered interstellar probe designed to reach 12% of the speed of light on its way to Barnard's Star."
Oxymoron? (Score:2, Insightful)
Workable Fusion Starship Proposed
If it's only a proposal, how do we know whether it is "workable" or not?
Re:Ramscoop design? (Score:3, Insightful)
We don't need more speed (Score:3, Insightful)
All the interesting places are either within reach now or too far to go there at ANY speed. What we really need is to find a way to autonomously survive in space for a long time.
That should have read... (Score:5, Insightful)
... Edward Teller, the self-described father of the hydrogen bomb.
Other people who worked on the project tend to disagree with that title.
Re:Relativity and time dilation make my head hurt (Score:5, Insightful)
Please read up on Relativity sometime. There are a number of decent resources on the subject.
As is, you've just lowered the IQ of everyone who read this post....
Specifically...
The time dilation effect on an object is irrelevant to an observer at its point or origin. It WILL reach its destination, unless it's aimed wrong, or hits something really hard.
No, there is no such speed as you propose in your second conjecture.
Time dilation is a wonderful thing. It helps to shorten trips from the point of view of the traveller. But it doesn't change the trip at all from the point of view of an observer back at the start point.
Unless, of course, you're carrying one end of a wormhole with you on the voyage. Still doesn't change the voyage from the point of view of the observer back home, but can have some interesting effects later (if, that is, you consider time travel interesting, of course).
Re:Great idea but pie in the sky... (Score:3, Insightful)
Moon colony, orbiting L5 colony, whatever it is it must be permanent and able to manufacture using locally sourced materials because building something like this from within the gravity well doesn't make economic sense.
Under what set of conditions does it make any sense to launch a manufacturing plant into space, then send up raw materials? I assume that's what you mean by "locally sourced" because there isn't any 'local' material at the L5 point.
How would that ever be cheaper than launching pre-built sections and assembling them in orbit?
Re:Great idea but pie in the sky... (Score:5, Insightful)
Moon colony, orbiting L5 colony, whatever it is it must be permanent and able to manufacture using locally sourced materials because building something like this from within the gravity well doesn't make economic sense.
Under what set of conditions does it make any sense to launch a manufacturing plant into space, then send up raw materials? I assume that's what you mean by "locally sourced" because there isn't any 'local' material at the L5 point.
How would that ever be cheaper than launching pre-built sections and assembling them in orbit?
No what I meant by locally sourced materials was either moon mined materials or asteroid mined materials. Probably the latter as I believe things like iron are a little weak [neiu.edu] on the moon.
There's no way shipping ANYTHING up from the gravity well would allow us to build a ship of this nature within any reasonable time frame with the exception of using absolutely huge space elevators.
Oh, but it gets better (Score:4, Insightful)
If you read the proposal, you'll note that the proposed method of working in space seems to be that the rocket engine actually fires in two directions - first, it fires a very high energy plasma beam AT THE SPACESHIP, which, in the vacuum of space, turns the whole assembly into a Gigavolt capacitor. THEN the spaceship fires a GV proton beam back at the rocket. This proton beam then ignites a classic fission explosion (using Deuterium-Tritium), but "very small", and this DT explosion ignites a second, much more explosive Deuterium-only fusion explosion AWAY FROM THE SPACECRAFT. Repeat one million times per second, or as needed.
What could possibly go wrong?
If that's not exciting enough, the whole plasma/proton beam doesn't work on earth, so, hey, we use a disposable argon laser, which can generate a lot of power, but (sadly), is really inefficient. But wait, we can fix that! All you have to do is set off a small hexogene explosion around your rod of solid argon, and the laser will suddenly work at 80% efficiency. Oh, repeat that every microsecond or so.
Honestly though, if you can get past the insane energies involved, he's come up with a rather brilliant way to use readily available fuel (Deuterium, as opposed to Deuterium Tritium, which is hard to come by), and using a whole chain of events, make the process really efficient (i.e. you need a lot less mass to make all this work). And, since your main burn is fusion (which consumes the fission by-products), not a lot of radiation to speak of (oh, well, there are some pesky neutrons, but who doesn't like neutrons?)
Re:Oh, but it gets better (Score:5, Insightful)
Did you know your car runs on explosions [wikipedia.org]? What could possibly go wrong? :P
Or do you ride a bike to work?
Re:100km/s (actual topic of proposal). (Score:3, Insightful)