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Workable Fusion Starship Proposed

Soulskill posted more than 5 years ago | from the for-sufficiently-difficult-values-of-workable dept.

Space 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."

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260 comments

These pretzels are making me FIRSTY!! (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#26684427)

These pretzels are making me FIRSTY!!

Oxymoron? (2, Insightful)

gzipped_tar (1151931) | more than 5 years ago | (#26684433)

Workable Fusion Starship Proposed

If it's only a proposal, how do we know whether it is "workable" or not?

Re:Oxymoron? (5, Informative)

getuid() (1305889) | more than 5 years ago | (#26684543)

If what you are proposing relies on technology already in use, or which could very likely be made usable during the next few years (i.e. technology which's basic scientific implications we understand, but just need a little time to figure some "engineering details"), then it's workable. If not, then most probably it's not.

Re:Oxymoron? (-1)

Anonymous Coward | more than 5 years ago | (#26684703)

MOD PARENT DOWN.

He's a fucking tool that pretends to be insightful.

Jesus. His sig sucks, too.

Re:Oxymoron? (0)

Anonymous Coward | more than 5 years ago | (#26684791)

What *is* his sig and how do you see it as AC?
Please!

Re:Oxymoron? (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#26685849)

How fucking stupid are you? You log in and post as AC. DUH.

Re:Oxymoron? (0, Offtopic)

onemorechip (816444) | more than 5 years ago | (#26685971)

He might be logged in but posting anonymously, that means he can see the sig, which BTW is "So this is how Linux dies. With thunderous applause."

Re:Ramscoop design? (2, Insightful)

wjh31 (1372867) | more than 5 years ago | (#26684485)

what with how sparse the ISM is, i cant personally see that that would be workable

Re:Ramscoop design? (5, Informative)

geckipede (1261408) | more than 5 years ago | (#26684621)

Actually it's too dense. At high speeds (significant fractions of lightspeed) a magnetic scoop acts like a very effective braking system in interstellar gas. A Bussard type ramscoop rocket could only be expected to reach about 0.12c even with highly efficient engines.

Re:Ramscoop design? (3, Funny)

wjh31 (1372867) | more than 5 years ago | (#26684655)

ah yes, it would have helped if i had read the ramscoop wiki rather than reading the name and guessing what it meant

100km/s (actual topic of proposal). (0)

Anonymous Coward | more than 5 years ago | (#26685125)

Somehow, from the very first post, this thread got derailed onto a discussion of the speed of light. The paper assumes 100Km/s. Light is 300,000 Km/sec.

We're talking about trips within the solar system.

Re:100km/s (actual topic of proposal). (2, Insightful)

Psion (2244) | more than 5 years ago | (#26686407)

And yet the story's title refers to a 'starship'.

Re:Ramscoop design? (2, Interesting)

Anonymous Coward | more than 5 years ago | (#26686139)

Really? Could a magnetic scoop then be used for braking on a ship that used a different type of propulsion? Because more than half your propellant on an interstellar journey is required due to the need for braking when you get to your destination.

Re:Ramscoop design? (3, Funny)

Anonymous Coward | more than 5 years ago | (#26684493)

I have designed a spaceship that uses a scoop to collect amazon affiliate codes.

It will be able to reach Barnards star in a matter of hours.

from the article.. (5, Funny)

Silm (1135973) | more than 5 years ago | (#26684455)

a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimegampere proton beam,

that has to be right up there with back to the future. I mean, it has a frickin' gigavolt-multimegampere proton beam

Re:from the article.. (2, Funny)

jimbo2150 (1396459) | more than 5 years ago | (#26686295)

I mean seriously folks, is it really too hard to ask for sharks with friggin' gigavolt-multimegampere proton beams strapped to their forehead?

To save time & skip the pdf (5, Informative)

Bearhouse (1034238) | more than 5 years ago | (#26684525)

Re:To save time & skip the pdf (4, Funny)

andereandre (1362563) | more than 5 years ago | (#26684747)

I have read the pdf. Looks good to me, could find no errors in the math, so make it so. Now back to watching pr0n.

In case anyone's wondering (0, Offtopic)

Anonymous Coward | more than 5 years ago | (#26684531)

The trailer for "Star Trek" is going to appear in the Stupor Bowl tonight, so this is part of the advance tangentially related news media that the companies use to whip up interest in the movie.

Re:In case anyone's wondering (2, Interesting)

moteyalpha (1228680) | more than 5 years ago | (#26685291)

That was very interesting as I knew what was going on with the associated news stories that are planted but never knew it was so aptly named. I wonder , do the movie promoters pay the people to do the articles, or are they just lazy, and if somebody writes free copy for them, they jump all over it.
As far as the Nuclear drive, my brother ( who is a Nuclear Engineer ) and I have discussed it for over 30 years and though it might work, it could also end up buried somewhere with a message "Do not open until Christmas 40010".

Re:In case anyone's wondering (-1, Troll)

Anonymous Coward | more than 5 years ago | (#26686249)

my brother ( who is a Nuclear Engineer )

Hi, we're from (country), and we are offering a job to your brother. In fact, he's already on his way to our country as we speak...

Great idea but pie in the sky... (4, Interesting)

Cheerio Boy (82178) | more than 5 years ago | (#26684565)

I'm all for ideas like this but we won't be building things like this until we, as a planet, have a permanent manufacturing presence in space.

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.

Re:Great idea but pie in the sky... (5, Funny)

xch13fx (1463819) | more than 5 years ago | (#26685029)

If anyone needs a colonist I was recently laid off. I can weld and swim well.(You swim to move in zero g right?).

Re:Great idea but pie in the sky... (2, Insightful)

TubeSteak (669689) | more than 5 years ago | (#26685101)

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... (4, Insightful)

Cheerio Boy (82178) | more than 5 years ago | (#26685179)

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.

Re:Great idea but pie in the sky... (1)

A nonymous Coward (7548) | more than 5 years ago | (#26685467)

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.

*THE* gravity well?

The moon has one too. Asteroids have a different but similar problem in being so far away and having such different orbital mechanics.

What exactly are you proposing?

Re:Great idea but pie in the sky... (4, Interesting)

Cheerio Boy (82178) | more than 5 years ago | (#26685601)

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.

*THE* gravity well?

The moon has one too. Asteroids have a different but similar problem in being so far away and having such different orbital mechanics.

What exactly are you proposing?

For practical engineering purposes the gravity well of the moon is weak enough to not be a problem for the transportation of materials off it's surface.

Asteroids do have gravity obviously but almost nothing due to their size. Thus materials transported from them are again easy to move into open space.

What I'm proposing is this:

1) Establish a colony on the moon or at L5.

2) Use moon materials to build the manufacturing framework.

3) Construct mining ships for asteroid field work.

4) Mine asteroids and use the materials to construct the large-scale interplanetary transport.

Now while this is a workable plan it is _also_ pie-in-the-sky as we can't even get our collective butts to agree on how to get a primary established off planet.

My memories of Edward Teller (4, Interesting)

MarkWatson (189759) | more than 5 years ago | (#26684589)

Edward Teller hired my Dad into the Physics department at UC Berkeley and I remember him as a gentleman - he was occasionally at our house. Once my parents had a costume party and Teller was provided with a bird costume - he did not want to wear the mask so he had these big white wings on. The SF Chronicle columnist Herb Caen ran a story the next day saying that Teller was dressed as the angel of peace. Until Teller died a few years ago, my Dad would occasionally travel to Berkeley to visit with him.

Re:My memories of Edward Teller (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#26684755)

Teller was a K U N T with a capital K.

Re:My memories of Edward Teller (1)

Hal_Porter (817932) | more than 5 years ago | (#26685041)

Given that he disagreed with all the other physicists about politics, how do you know he isn't just the victim of character assasination from them?

I remember reading a hatchet job profile of him in Scientific American and thinking he had a much more realistic view of totalitarianism than Communist sympathizers [wikipedia.org] like Openheimer.

Re:My memories of Edward Teller (5, Informative)

Anonymous Coward | more than 5 years ago | (#26686199)

I think it is inaccurate to categorize Oppenheimer as a communist sympathizer. My understanding is that Oppenheimer was more in favor of the Utopian ideals of communism and not the reality of Soviet Russia.

But the root of the problem between Teller and Oppenheimer was that Oppenheimer opposed the hydrogen bomb (fission/fusion) and Teller was all for it. That made Oppenheimer an enemy to Teller.

Teller, instead of leaving it as a difference of opinion as to whether such a powerful weapon was needed, went on the attack and set out to discredit Oppenheimer.

In the cold war it was pretty easy to make Oppenheimer seem subversive. The time was paranoid and anyone with a different opinion was suspect. Others set out to paint anyone as communist who they didn't agree with. Teller used it to his advantage to silence and discredit a rival.

Who knows if Teller or Oppenheimer was right. No fission/fusion device has ever been used in war. The only devices that have been used were the ones that Teller and Oppenheimer and many others invented.

However, a good person, a patriot, and someone who in spite of his own misgivings about the kind of weapon he helped develop, did it anyway and in so doing probably saved hundreds of thousands of American lives, had his own life destroyed because Edward Teller was on a personal quest for his own glory, his own stature, and his own place in history.

Edward Teller was an asshole. He took it personal that Oppenheimer opposed developing the hydrogen bomb and set out to destroy Oppenheimer for it.

Re:My memories of Edward Teller (1)

stox (131684) | more than 5 years ago | (#26685145)

Edward was a remarkable man. Fortunately, not too long before his death, he published his memoirs, which give great insight into his thoughts and outlooks. He was far from perfect, but no real man is.

Re:My memories of Edward Teller (3, Informative)

Vellmont (569020) | more than 5 years ago | (#26685363)


The SF Chronicle columnist Herb Caen ran a story the next day saying that Teller was dressed as the angel of peace.

An interesting story about a man who was awarded the first Ig-nobel prize for peace: [improbable.com]

for his lifelong efforts to change the meaning of peace as we know it.

Then a miracle occurs... (3, Informative)

Monsieur Canard (766354) | more than 5 years ago | (#26684595)

One of my grad school profs worked on a project like this. The concept involved a ship farting (for lack of a more appropriate term) out a series of small fusion bombs. When they went off the heat would cause the shielding at the rear of the ship to sublimate, and this ablation process would drive the ship. As I recall there were only two teensy problems with this: 1) even with the best shielding material available today, the intense heat from the detonation would still cause the maximum heat in the shield to occur at a depth greater than the surface (i.e. the shield would come off in great blobs instead of the slow steady ablation required for thrust) and 2) the amount of anti-matter required for the devices was only about a million times the total amount ever produced on Earth.

But apart from that it worked like a champ.

A great way to make contact with aliens . . . (3, Funny)

PolygamousRanchKid (1290638) | more than 5 years ago | (#26684677)

. . . speeding through their neighborhood whilst "farting out a series of small fusion bombs."

They will come looking for us.

"Hey, Earthling, is this your flatulent spacecraft that fouled our air? We'd just like to return it to you, by chucking it at one of your major cities."

Re:Then a miracle occurs... (1)

Guysmiley777 (880063) | more than 5 years ago | (#26684789)

What does anti-matter have to do with it?

Re:Then a miracle occurs... (1)

Monsieur Canard (766354) | more than 5 years ago | (#26684903)

Good question. Almost as good as what was a guy that sits on a space propulsion committee doing teaching Gaussian quadrature to a bunch of slacker engineers?

I may have combined a couple of his papers on that one, I'll have to look when I get home. It may have been one using fusion and one using anti-matter. I loved hearing his stories about some of the papers he had to review as part of the committee, some were downright interesting, but most seemed to involve some sort of device that pissed-off the 2nd law of thermodyamics and annoyed conservation of energy.

Anathem (0)

Anonymous Coward | more than 5 years ago | (#26685375)

The spaceship is driven with a technology like this

Re:Anathem (1)

trav242 (645556) | more than 5 years ago | (#26685743)

Well, sort of. Remember, the Daban Urnud is made of matter with, in some cases, significantly different properties than the inhabitants of Arbre...

Human starship has already landed on Mars? (1)

C0quette (1466487) | more than 5 years ago | (#26684647)

http://ida.wr.usgs.gov/fullres/divided/m15012/m1501228a.jpg [usgs.gov] That is a NASA picture from Mars. Can anyone come with a good explanation what it shows?! To me it looks like some bhuman built biosphere, yet from sci-fi literature. .

Re:Human starship has already landed on Mars? (0)

Anonymous Coward | more than 5 years ago | (#26684673)

That is clearly a Martian. Someone hasn't read his Stranger in a Strange Land.

Re:Human starship has already landed on Mars? (1, Informative)

Anonymous Coward | more than 5 years ago | (#26684709)

It's just the splash from an impact, probably a meteor. Imagine this:

http://www.core77.com/blog/images/drop_splash.jpg

but with the material property changing mid splash, possibly from the heat of impact.

Earth has them too, but we have more erosion due to weather:

http://www.geocities.com/zlipanov/impact_craters/impact_craters.html

Re:Human starship has already landed on Mars? (1)

C0quette (1466487) | more than 5 years ago | (#26684799)

One of those pictures shows the "Wolfe Creek": http://www.geocities.com/zlipanov/impact_craters/wolfe_creek-australia.jpg [geocities.com], which is a "relatively well-preserved crater that is partly buried under wind blown sand. The crater is situated in the flat desert plains of north-central Australia. Its crater rim rises ~25 meters above the surrounding plains and the crater floor is ~50 meters below the rim. Oxidized remnants of iron meteoritic material as well as some impact glass have been found"

However, it does not retain anything like a dome, or, a droplet frozen in action due to heat... And, the steep rim to the crater floor shows no major signs of erosion. Next explanation, please.

Re:Human starship has already landed on Mars? (1)

Hal_Porter (817932) | more than 5 years ago | (#26684901)

Well if its not a frozen droplet it must be a human built biosphere.

LOL (1)

C0quette (1466487) | more than 5 years ago | (#26685031)

LOL. I was trying to avoid that, but realize the my bloody foot is aching. The "golf-ball surface" is annoying too. Surely, someone has a better resolution image somewhere. The so-called Face on Mars (http://www.space.com/scienceastronomy/060921_mars_images.html) was defaced here http://www.space.com/images/060921_mars_faceB_02.jpg [space.com]. I am sure this "biosphere" must be defaced too, somewhere.

Re:Human starship has already landed on Mars? (1)

venuspcs (946177) | more than 5 years ago | (#26684813)

If it was (ever) a Biosphere it was a long time ago. Blowing it up you can clearly see that the bottom (and bottom right) of the object has been destroyed/eroded and the top (presumably the entrance) is almost completely buried.

Re:Human starship has already landed on Mars? (1)

ezsailor (683625) | more than 5 years ago | (#26684973)

Oh c'mon. You can clearly see that it is the nose of the God of War....

Re:Human starship has already landed on Mars? (4, Informative)

Urza9814 (883915) | more than 5 years ago | (#26684981)

Dude...you've got what appears to be about a 50px kinda round thing in a crater, and your first assumption is a man-made biosphere? Well, I've got about a hundred pictures of alien spacecraft for you to look at then....

Seriously though, different planets have vastly different conditions, so it's no surprise you don't see things like this on Earth. I'd say it's essentially a sand dune. There's a _lot_ of similar formations on Mars. In fact, there's a few more on the string of pictures that original is from:
http://ida.wr.usgs.gov/html/m15012/m1501228.html [usgs.gov]

There's one in the first image, there's some somewhat similar phenomenon in the second and third, there appears to be one in the fourth, two in the fifth, and part of one in the sixth.

Re:Human starship has already landed on Mars? (1)

im_thatoneguy (819432) | more than 5 years ago | (#26686269)

It's a pristine impact crater.

Look around it there are at least 30 others in progressively more eroded states ALL AROUND IT. IN THE SAME PHOTO.

Impact crater with bump in the middle... impact crater with bump in the middle... impact crater with bump in the midle. that one is just much less windswept and eroded.

Use your eyes not your crazy brain. No on second thought... use your crazy brain. It fails the brain test too.

Don't you think NASA would photoshop out a secret NASA project. Or at least not send the sattelite to image its itsy bitsy little mars colony acros the vastness of Mars? Do you know what the chances of that are? Even if they didn't know about it they would then suddenly be excited or censor it when someone told them.

Not to mention it's pretty tricky to diver several trillion dollars to build a mars base without anyone noticing.

Such audacity.... (1, Funny)

Anonymous Coward | more than 5 years ago | (#26684661)

It takes a lot of balls [wikimedia.org] to travel several light years without a road-side service plan.

Relativity and time dilation make my head hurt (0, Redundant)

caseih (160668) | more than 5 years ago | (#26684663)

Something I've always wondered about with regards to Project Daedalus and the like is the effects of time dilation as the velocity increases. I suppose at 0.12 * C the time dilation on the probe relative to, say, observers on Earth and Barnard's star is probably minimal. But it seems to me that going faster and faster you reach a point where although it might only take the probe x number of years to reach the star, on Earth it takes significantly more time. Therefore in the case of an unmanned probe, since it's time passage on earth that matters, at a certain point it's not desired to have the probe go any faster.

This line of thought leads to some interesting, paradoxical situations. First, as an object approaches C the time dilation effect becomes such that from a frame of reference of the origin, the object never in fact can reach its destination. Would it not become in essence stuck in time? Secondly there must be some point at which if an object is travelling at x*C, there must be a speed y*C such that another object could reach its destination before the first object, even though the second object is travelling at a lower velocity relative to C. Or maybe not since both objects do experience time dilation.

Re:Relativity and time dilation make my head hurt (2, Informative)

Anonymous Coward | more than 5 years ago | (#26684763)

no not at all u have it completely wrong
as u approach the speed of light
time at that velocity "slows" down

so if something is 6 light years away
and u are going .5 light speed
then it takes 12 years

so on earth 12 years would pass for it to arrive
however if u were on the ship it would take less then 12 years to arrive

in the extreme case if it was 6 light years away
and u were going light speed then on earth it would take 6 years for the ship to arrive
but if u were on the ship it might take seconds or no time at all

so the ship still moves and time in that frame of referance slows down but remains the same else were

Re:Relativity and time dilation make my head hurt (4, Insightful)

CrimsonAvenger (580665) | more than 5 years ago | (#26684825)

First, as an object approaches C the time dilation effect becomes such that from a frame of reference of the origin, the object never in fact can reach its destination. Would it not become in essence stuck in time? Secondly there must be some point at which if an object is travelling at x*C, there must be a speed y*C such that another object could reach its destination before the first object, even though the second object is travelling at a lower velocity relative to C. Or maybe not since both objects do experience time dilation.

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:Relativity and time dilation make my head hurt (5, Informative)

MoralHazard (447833) | more than 5 years ago | (#26684831)

From your post, you don't make it 100% clear, but I suspect your understanding of time dilation might not be 100% accurate.

Say the distance from Earth to another star is 1 light-year, and we manage to accelerate a probe to an average speed of 0.1*c (1/10th the speed of light). For the sake of our thought experiment, let's assume the probe comes back, too, for a total trip distance of 2 light-years.

On earth, 20 years will have passed--it's a simple, easy "distance = rate * time" kind of thing. No time dilation to consider.

If you placed a clock on the spaceship, though, you'd see some time dilation effects on the moving clock. It would have experienced less than 20 years' worth of time passing. So if your Earth-bound clock and your space clock were perfect, and you synced them up before the trip started, they would be out of sync when the ship got back.

Remember, in your own reference frame, you don't experience any time dilation. The fact that the ship is travelling fast doesn't make clocks on Earth run slower.

If this isn't clear, go read the Wikipedia article on time dilation, and read the part where it talks about muons decaying as they travel from the upper atmosphere to the surface of the Earth. That's the easiest example to understand, I think, as long as you get how radioactive decay operates.

Re:Relativity and time dilation make my head hurt (1)

PatrickThomson (712694) | more than 5 years ago | (#26685589)

I think the point the GP was trying to make is a valid one - if we made a probe that travelled to a certain star at 0.9c, there's no point doubling its fuel tanks so it can go at 0.95c. From our P.O.V, the probe would take 19 years instead of 20 - clearly not worth it. If it was a manned spaceship, the time dilation would reduce the supply requirements sufficient that it might be worth it.

Re:Relativity and time dilation make my head hurt (1)

MoralHazard (447833) | more than 5 years ago | (#26685769)

Patrick, did you read the second paragraph in the GGP? If not, go back and look at this quote:

"First, as an object approaches C the time dilation effect becomes such that from a frame of reference of the origin, the object never in fact can reach its destination. Would it not become in essence stuck in time?"

This is nonsensical in special relativity. In the frame of reference at the spacecraft's origin (Earth), the spacecraft will certainly reach its destination eventually as long as it has a positive velocity on that course. Time dilation's got nuthin to do widdit, there is no "time dilation effect" on our perception of how long it takes for the craft to reach its destination. If the craft moves with an average speed of 0.1c, it will take 10 years to reach a star that is 1 light-year from Earth. Period.

And WTF about the "stuck in time" part? Maybe he's thinking of how an observer perceives an object travelling toward the event horizon of a black hole. In that scenario, the object appears to slow down asymptotically as it approaches to the event horizon, never actually reaching it, at least to an outside observer.

You make a good point, in your post. In the GGP's case, though, I think he's on a completely different track.

Re:Relativity and time dilation make my head hurt (1)

PatrickThomson (712694) | more than 5 years ago | (#26686501)

the GGGP is getting a little confused. From a stationary observer's P.O.V, time slows down for someone else going faster and/or falling into a black hole, and if that traveller were ever to reach C (or the event horizon) time would stop. From the traveller's P.O.V, they cover a light year in much less than a year, and the length contraction turns the universe into a paper-thin disk of dust that they promptly slam into and explode. I always found that amusing.

Light Speed Too Slow?? (1)

rogeroger (1125533) | more than 5 years ago | (#26686019)

Prepare ship for ludicrous speed! Fasten all seatbelts, seal all entrances and exits, close all shops in the mall, cancel the three ring circus, secure all animals in the zoo! (Colonel Sandurz)

Re:Relativity and time dilation make my head hurt (1)

ZombieWomble (893157) | more than 5 years ago | (#26684865)

You're slightly misunderstanding the effects of time dilation here - time dilation from the probe's point of view has absolutely no effect on the time a "stationary" observer sees its journey take.

As the probe speeds up, the time the observer on earth sees it take remains equal to the distance it must travel divided by its velocity (in Earth's frame). Time dilation affects the probe because what the probe sees is a relativistic shortening of the distance it must travel, thus giving a reduced total time of travel. This is resolved by the probe experiencing a reduced journey time compared to the time which passes on earth.

As a result, the second paradox you describe does not occur (although the concept of simultaneity does get kind of wacky in relativity in other ways).

Re:Relativity and time dilation make my head hurt (1)

venuspcs (946177) | more than 5 years ago | (#26684889)

That is an interesting paradox, but it is flat out wrong. If you take two remote control cars (one capable of 40 mph and one capable of 20 mph) and you have the 40 mph car take off, then half a minute later the 20 mph car and they are both going the same direction for 1 mile. Which one will get there first? Now do the same with a couple of jet airplanes both flying the same direction leaving 30 minutes apart with the first one flying at Mach 5 and the second at Mach 2.5. Again the faster one will get there first. Frame of reference aside this is true. Now with that said if you took two space ships, one traveling at .5c and one traveling at .25c and had them leave a year apart (with the faster one first), both traveling in the same direction. It would appear to us (hear on Earth) through Visual Observations that the slower one gets to the destination at the same time (or close to it) as the faster one. That is an optical illusion caused by speed. However, they would not arrive at the same time or even any where close to the same time. They would arrive relative to the distance/speed they where traveling just like the remote control cars or the jet planes. However, relative the person(s) onboard the space crafts the persons on the slower (.25c) craft would age at almost three times the speed of those on the .5c craft.

Re:Relativity and time dilation make my head hurt (3, Informative)

david.given (6740) | more than 5 years ago | (#26684997)

But it seems to me that going faster and faster you reach a point where although it might only take the probe x number of years to reach the star, on Earth it takes significantly more time. Therefore in the case of an unmanned probe, since it's time passage on earth that matters, at a certain point it's not desired to have the probe go any faster.

Actually, it's the other way round; from the point of view of someone on Earth, clocks on a rapidly moving spacecraft appear to go more slowly.

The actual time dilation factor, known as the Lorentz factor, is a simple 1/sqrt(1 - v^2), so for your vehicle going at .12c the difference in speed in clocks is 1.007 --- as you say, negligible. An observer on Earth sees a second metronome on the vehicle tick every 1.007 seconds.

This usually works out to your advantage. Passengers on a fast-moving ship will have less time to get bored, and there'll be less wear and tear on the structure. A sufficiently fast moving ship can cross the galaxy in subjective days (see A World Out Of Time by Larry Niven), although you're still going to get to your destination at least 100,000 years later. (You'd need a Lorentz factor of about 5000000 for that, which means you'd need to be travelling at 0.99999999999998c.) OTOH you run into severe navigational problems: such as the inability to dodge oncoming obstructions. Because, of course, the faster you go, the less warning you have of them...

Re:Relativity and time dilation make my head hurt (1)

rachit (163465) | more than 5 years ago | (#26686399)

Not to mention the acceleration getting to that speed would either take a very long time or turn the passengers into soup.

Re:Relativity and time dilation make my head hurt (0)

Anonymous Coward | more than 5 years ago | (#26686425)

And, since your mass is also dilating, the amount of energy it takes to accelerate is always increasing, and some of those oncoming obstructions are dwarf galaxies you're pushing out of the way.

Emphasis on 'Workable Fusion' (0, Flamebait)

number6x (626555) | more than 5 years ago | (#26684687)

Shouldn't we have 'workable fusion' first in order to base the starship's propulsion system on it?

If we don't have to develop a workable fusion engine first, then they should use my idea. It will allow travel at twice the speed of light.

All we need is fairy dust and unicorn piss to power it.

Re:Emphasis on 'Workable Fusion' (1, Funny)

Anonymous Coward | more than 5 years ago | (#26684735)

I thought we had workable fusion. It just needs a bit of fission to get started...

Re:Emphasis on 'Workable Fusion' (1, Informative)

Anonymous Coward | more than 5 years ago | (#26684961)

We have a number of workable and controlled fusion devices. They just work on a small scale and need more power to work than they generate.

20 Years (1)

venuspcs (946177) | more than 5 years ago | (#26684715)

That is how long it will take before someone finally manages to open a sub-space corridor (warp drive).

We don't need more speed (3, Insightful)

Anonymous Coward | more than 5 years ago | (#26684751)

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.

Re:We don't need more speed (0)

Anonymous Coward | more than 5 years ago | (#26684815)

Alpha Centauri seems pretty interesting to me and at .12c we could get a probe there well within a single lifetime.

Re:We don't need more speed (1)

tylerni7 (944579) | more than 5 years ago | (#26685973)

I don't mean to sound like an asshole, but it's not that interesting.
Sure, it would be nice to send a probe there, because it is another star, but interesting is more like, Eridani, which is about 10ly away, but has a planet.
I'm not saying that Alpha Centauri isn't interesting, I'm just saying you're missing the point of the OP. The idea is that even if we were to be able to travel at the speed of light, we aren't going to be able to travel more than 70ly away. While there is plenty of stuff in a 70ly radius, compared to the entire universe, that's a tiny, tiny fraction of the space.
So, we either need to survive in space for a long time, or travel significantly faster than the speed of light.

As a side note, I suspect that trying to send humans out even 4.2 light years away would cause massive problems. Even if they traveled at the speed of light, being completely unable to communicate with anyone on Earth would probably drive them all mad, and if it did, no one would ever know until 4 years later.

Of course, this doesn't apply to probes, but ideally we would send humans out to other planets at some point.

Re:We don't need more speed (1)

perryizgr8 (1370173) | more than 5 years ago | (#26686189)

Even if they traveled at the speed of light, being completely unable to communicate with anyone on Earth would probably drive them all mad, and if it did, no one would ever know until 4 years later.

no, we'd have to wait 8.4 years. they've got to come back too.

Re:We don't need more speed (1)

tylerni7 (944579) | more than 5 years ago | (#26686367)

What? Are you suggesting that astronauts on an interstellar mission would wait until they are asked before they send a mission update?
I'm pretty sure they would send out status reports every day or so, regardless of whether anyone asking them.

I have no idea what you are proposing, and either way, it doesn't really change the gist of what I was saying.

Re:We don't need more speed (1)

VinylPusher (856712) | more than 5 years ago | (#26686483)

It sort-of does apply to probes though. They can't communicate with Earth, we can't communicate with it. Someone would have to do the risk analysis and work out the probability of the probe successfully scouting the remote target and returning within transmit distance of Earth.

Whatever that figure is, we would have to send out multiple probes to give any reasonable chance of a successful mission.

so... (0)

Anonymous Coward | more than 5 years ago | (#26684767)

...no warp yet?

c'mon, that's lame...

That should have read... (4, Insightful)

gyrogeerloose (849181) | more than 5 years ago | (#26684819)

... Edward Teller, the self-described father of the hydrogen bomb.

Other people who worked on the project tend to disagree with that title.

Re:That should have read... (1)

thegameiam (671961) | more than 5 years ago | (#26685371)

I'd characterize Teller's role in the H-bomb as similar to Oppenheimer's role for the A-bomb. As Oppenheimer is routinely called the "father" of the A-bomb, it seems reasonable to use the same language. Obviously, both projects were the result of a substantial number of people working a lot of hours.

Re:That should have read... (1)

Scaba (183684) | more than 5 years ago | (#26685571)

My mother had the same problem whenever my father would describe himself as such. How could he be the father when she worked on the project, too?

Kinda optimistic (2, Informative)

Ancient_Hacker (751168) | more than 5 years ago | (#26684945)

Hmmm, if we can't build lasers and power supplies like that on Earth, even given tens of years and billions of $, how soon will these be doable in outer space, with 100% reliability.

The old project Orion looked into atomic kabang propulsion. There were a few major showstoppers-- two dud impulses in a row and the pusher plate goes flying off into space. No way on Earth to test it. Which is kinda important for a device that has to be 100% reliable with no misfires.

Also the idea of discharging all those Joules in 10 nanoseconds is mighty ambitious-- just the inductance of the objects limits the rate of current rise to a whole lot more than that.

Re:Kinda optimistic (4, Funny)

DriedClexler (814907) | more than 5 years ago | (#26685059)

Yeah, and what's worse, they can't even get acronyms right:

practical fusion-powered spacecraft (PDF).

That should be abbreviated as PFS or PFPS, not PDF.

Only 12%? (0)

Anonymous Coward | more than 5 years ago | (#26685133)

only 12 percent of the speed of light? pussies.

Where is the ZPM? (1)

Joe The Dragon (967727) | more than 5 years ago | (#26685285)

Where is the ZPM?

Re:Where is the ZPM? (1)

The MAZZTer (911996) | more than 5 years ago | (#26686343)

Actually in the Stargate universe currently (end of Season 5) the humans of Earth have multiple ZPMs. Spoilers ahead if you haven't seen the last episode of Season 5 yet.

.

.

.

Two were taken back to the Milky Way after the Replicators occupying Atlantis back in Season 3 were destroyed. One of those was put aboard the Odyssey to help give them a chance against the Ori. It's never again mentioned but it's likely still there. In addition I find it interesting that at the time of the last Atlantis episode the Odyssey is on a super-duper top-secret mission... maybe that's the next SG-1 movie? Though I thought they were gonna spice up the SG-1 pilot for that, but I can take an original picture instead. :)

The other ZPM was used to power the Ancient drone chair on earth. The chair was destroyed but the ZPM was not mentioned. I guess the writers are free to either write it off as being destroyed or having the SGC/IOA use it somewhere else.

Three are currently powering Atlantis.

So five in total.

Oh, but it gets better (4, Insightful)

capn_nemo (667943) | more than 5 years ago | (#26685429)

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?)

Pretty obvious? (0)

Anonymous Coward | more than 5 years ago | (#26685825)

Why would anyone propose a non-functional fusion starship? Duh.

My capacitor is bigger (1)

VernorVinge (1420843) | more than 5 years ago | (#26685891)

There is a laser bombardment fusion device at Lawrence Livermore which I had the pleasure of visiting in college. The actual yield on the device never got close to break even, and the project was deprioritized in favor of the ITER tokamak. The peper makes no suggestions on how a ship will generate and store the necessary gigajoules of energy to maintain a sustained reaction. We may need a separate nuclear reactor to providing the ignition energy.

Woah (1)

Arancaytar (966377) | more than 5 years ago | (#26686327)

reach 12% of the speed of light on its way to Barnard's Star.

That is fast, but since Barnard's Star is 6 light years away, assuming a constant acceleration and deceleration it would still take 100 years to arrive.

Amazing (1, Offtopic)

Eravnrekaree (467752) | more than 5 years ago | (#26686393)

Building a starship is the least of our concerns. It baffles me that we are discussing building a fusion spaceship when it seems that very little is being done to get fusion working for making our energy here on earth. Our priorities are all mixed up. While we are spending billions on wars to give money to banks so they can use it to by their yachts, we desperately need to be spending that money on fusion and clean, environmentally friendly energy sources NOW. We cant afford to wait any more on this.

It amazes me there is not a more strong and powerful call from scientists globally to rapidly expand fusion research adn development. We should be funding not one but many different technologies via government funding, having a sort of competition with different designs being tested. With several projects development different designs and with funding to new designs that can do fusion better, cheaper and smaller, such as the Polywell, we have a better chance of getting something that will work.

With our destroying our planets environments with CO2 and toxic fossil fuel related wastes and set to totally deplete the entire supply of oil in 40 years, and with a supply that simply cannot bring electricity to everyone on planet, such as those in Africa, to alleviate the poverty and suffering there, our energy crisis for producing energy for use here on earth is the greatest challenge we face. If fusion is feasible for a spaceship, why the hell are we not building fusion plants right now or at least spending billions on development of this. We need to stop dilly daddling around here, we cant afford to sit around longer and wait for markets to somehow come up with a solution. Its clear that government funds most nuclear fusion development and corporations are not doing what we need to be doing to solve our worlds problems.

If we can develop fusion, global warming is solved and we dont have to worry about it anymore. Then why are we not doing it. Why is it sometimes I get the feeling that while everyone moans about global warming, no one wants to take the initiative and actually fix the problem? There needs to be a strong call from the scientific community to expand funding for fusion development and research as well as other renewable, environmentally friendly technologies. We need to tax the oil companies as well so that we can fund these projects with the money that consumers are struggling to pay at the pump. While we have a planet in crisis it makes me FURIOUS that oil company CEOs are using money wrenched from hardworking people via their monopoly to fund their yachts when we desperately need this money to be put into fusion research. Its like these wealthy CEOs are saying to the people of the world "screw you all, Im going to spend all of the money on my yachts and let this planet go to hell". That we see so little priority on this energy crisis in government policy, in regulating oil company profits and through a democratic and science directed process regulating their research and development priorities around goals of eliminating fossil fuel dependance ASAP? We cant afford inaction and the same old same old with oil companies wanted to pollute the environment and oceans with their rigs, to spend all of their money on yachts and oil exploitation, and for fleets of wasteful fuel inefficient 20 mpg cars when we can have 80 mpg NOW. Is it because they want their to be a global warming crisis, for whatever political agenda they have?

Re:Amazing (0, Offtopic)

Eravnrekaree (467752) | more than 5 years ago | (#26686415)

I would like to add, with what they are doing and their frittering away the money of their "oil pump taxpayers" from their duopolies, those CEOs are going to need those yachts to visit their beachside cottages and plush new york condominiums, on diving expeditions. They will be underwater.

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