Interstellar Travel proposals?

[qso1]

barobrain:<br />But someone was talking about actually sending out a spacecraft to meet the comet and use the gravity of the ship to "nudge" it safely out of the way.<br /><br />Me:<br />Even a relatively small fragment of comet is far more massive than a spacecraft for which we have launch capability. A craft could detonate a 1 Mt H bomb near the comet at distance and accomplish the nudge, theoretically anyway.<br /><br />But more importantly is the distance at which the craft must rendezveous with the comet/asteroid impactor. If we are able to do this, the interstellar travel scenario based on doom is negated. This gets back to my comment on the plausibility of leaving Earth due to doom and gloom. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[vogon13]

Some theories of the surface of Venus posit a massive volcanic episode that may have affected the whole planet. Is this scenario categorically ruled out for earth?<br /><br />{how 'bout that, a whole new way to destroy the world . . . .}<br /><br />(might want to keep the Orion blue prints handy)<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[qso1]

vogon13:<br />Some theories of the surface of Venus posit a massive volcanic episode that may have affected the whole planet. Is this scenario categorically ruled out for earth?<br /><br />Me:<br />Don't know for sure if the scientific community has ruled it out for earth. IMO, the only way I can see such an event would be for the surface of a planet to be strong enough to keep subsurface molten materials bound up. But with this comes the eventual pressure build and release that would lead to a massive volcanic episode. In the Venus scenario, the crust would have to be really thick or very strong or both. While that may have happened on Venus, I doubt it could happen here because our active volcanoes release pressure which kind of regulates earth and earth is covered largely by water which would act as an inhibitor for all but the most extreme volcanic activity.<br /><br />On Venus, I kind of go with the greenhouse effect which would have been cause by Venus tidally locking for the most part around the sun. 112 IIRC, days of solar heating on an atmosphere that may once have been more like the earth. The greenhouse effect eventually causing perpetual cloud cover until we have the Venus of today.<br /><br />Your right, we just might want to keep those Orion prints around.. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[quarkstorm]

20km!! 20 million tons!!!<br /><br />I don't know where these figures are coming from, typical proposals I've seen were to build a ship of about a few thousand tons.<br /><br />A mid-range Orion would have had a pusher plate diameter of 40m, it would have weighed maybe 2000 tons and would use 1080 bombs. Ablation of the pusher plate from the bombs would in actuall fact be quite low and would be reduced by coating the plate with a silicon based oil. The largest Orion design even considered was a "Super-Orion" 400m in diameter. THe 40m model was certainly feasible in 1960 and remains feasible today. If you follow the link in my sig there is an Orion discussion board.<br />http://en.wikipedia.org/wiki/Project_Orion#Sizes_of_Orion_vehicles ~ Orion Wikipedia article<br /><br />http://www.angelfire.com/stars2/projectorion/ ~ Orion site provides a good introduction on the subject. Read "Why build an Orion" "Why launch and Orion" and "Fallout Fallicies"

 

[qso1]

The figures come from various Orion design studies, the 20Km copper plate from the link below.<br />http://www.astronautix.com/lvs/oritsink.htm<br /><br />Other links for Orion:<br />http://www.astronautix.com/lvfam/orion.htm<br />http://www.astronautix.com/lvs/oriative.htm<br />The Orion ablative design calls for as many as 300,000 nuclear bombs. The U.S. and Soviet Union built perhaps 50,000 bombs between them during an almost half century arms race at a cost of trillions of dollars. Of course, the bombs alone may be relatively cheap to build but as with other aerospace projects, Orion designs eventually might have items not originally foreseen that would drive up its total cost. This has been the actual history of aerospace and space projects since about the mid 1970s.<br /><br />It has also never been demonstrated that nuclear explosives can be fired at the rapid pace required by Orion.<br /><br />As for the midrange design you refer to, I don't doubt the possibility of doing it although I suspect it would be more difficult than the original designers may have realized. Mainly I doubt the economic practicality of it or any of the Orion designs.<br /><br />Excerpt from Wiki:<br />Even at 0.1c, Orion thermonuclear starships will require a flight time of 44 years to reach Proxima Centauri, the nearest star.<br /><br />Me:<br />At 100% C, the flight time would be 4.4 years to Proxima.<br />At 10% C, the flight time would be 44 years.<br />At 1% C, the flight time would be 440 years.<br />At 0.1c, the flight time would be 4,400 years.<br />If you edit this portion of Wiki that I excerpted, are you sure the .1c figure of 44 year transit time to Proxima for Orion (Or any vehicle at .1C) is correct?<br /><br />Assuming the Orion is the way to go, another reason its not practical h <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[quarkstorm]

<i>The figures come from various Orion design studies, the 20Km copper plate from the link below. <br />http://www.astronautix.com/lvs/oritsink.htm </i><br /><br />This article is either factually inaccurate in the extreme or it is a proposal for some hypothetical "Extra-Super-Orion." If you read the links I posted you will see that the mainstream Orion ideas were somewhat more realistic and practical. A few thousand tones not a few million with a pusher plate 20- 40 metres across not 20 kilometres.<br /><br /><br /><i>Me: <br />At 100% C, the flight time would be 4.4 years to Proxima. <br />At 10% C, the flight time would be 44 years. <br />At 1% C, the flight time would be 440 years. <br />At 0.1c, the flight time would be 4,400 years. </i><br /><br /><br />0.1C is 10% C

 

[qso1]

quarkstorm:<br />This article is either factually inaccurate...<br /><br />Me:<br />Nonetheless it was there and I referenced it because if one is going interstellar, the most cutting edge methods of reaching an interstellar destination are going to be required.<br /><br />I knew you'd say that, thats why I broke the speed thing down the way I did because the decimal is before the 1 and that to me implies going below numeral 1. 10% would have sufficed. And again, I don't think it will ever be practical to build a starship of anykind with existing or near term tech as long as we live in the current economical situation.<br /><br />quarkstorm:<br />A few thousand tones not a few million with a pusher plate 20- 40 metres across not 20 kilometres...<br /><br />Me:<br />Look at the tonnes figure. A few thousand? Thats still beyond any demonstrated practical space capability I have ever seen. ISS might weigh in at 500 tons by now but its not very practical in terms of how it was taken to orbit.<br /><br />If private enterprise cracks the cost barrier in another decade or two, the Orion you mention, and there were several types studied, including the original which was interplanetary rather than interstellar. But the Orion you mention may be practical as far as getting it to orbit.<br /><br />But even you called it somewhat realistic and practical.<br /><br />Bottom line is the cost barrier which defines practically in today or the near futures terms.<br /><br />Orion would require a hefty budget if done the traditional NASA/contractor approach. In this approach, they will say Orion is easy to do for a few hundred billion, then as time goes on, they encounter the challenges of detonating nukes in rapid fire sequence, the challenges of keeping it on course, the materials that may be needed if current materials calculations are off. Not to mention requiring at least one demonstration of the vehicles propulsion before man rating it. Before you know it, the inevitable cost overruns (Trillions?)co <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[annodomini2]

<blockquote><font class="small">In reply to:</font><hr /><p>Me: <br />At 100% C, the flight time would be 4.4 years to Proxima. <br />At 10% C, the flight time would be 44 years. <br />At 1% C, the flight time would be 440 years. <br />At 0.1c, the flight time would be 4,400 years. <br /><br /><br />0.1C is 10% C <p><hr /></p></p></blockquote><br />I'm guessing its a typo, as 0.1% C would be 4400 years <div class="Discussion_UserSignature"> </div>

 

[nexium]

Hi annod: Yes/ a typo. You left out the % in the line with 4400 years. Also 4250 years is long enough unless we we decided the old distance to Proxima is about 5% short. Neil

 

[Aetius]

I've also read proposals of using a network of neutral particle beam generators (less complicated, less expensive than lasers) to fire a concentrated beam at a magnetic sail spacecraft. A laser aboard the magnetic sail spacecraft would ionize the incoming particle stream, which would then be deflected off the sail field, thus providing thrust.<br /> <br />The NPB generators could be constructed on Mercury, from mostly native materials. Launched into orbit around the planet, they would collectively use the powerful solar flux to propel interstellar spacecraft to enormous velocities.<br /><br />Anyone else a fan of this approach?<br /><br />I also like Zubrin's magnetic sail augmented Orion idea.<br /><br />If you could mine the He-3 from Saturn, Uranus, or Neptune, the fusion power available could help produce relatively large quantities of antimatter. Add some reaction mass from the Kuiper Belt for an added kick, and who knows? Maybe interstellar travel won't remain a pipe dream forever.<br /><br />The key is, in my opinion, that we must learn how to industrialize the planets first.

 

[qso1]

Interstellar travel is far enough into the future IMO that if we finally do it, it will probably be with something not imagined today.<br /><br />aetius:<br />The key is, in my opinion, that we must learn how to industrialize the planets first.<br /><br />Me:<br />I agree to a certain degree, that being maybe we could industrialize one of the gas giants. But before even that, we have to industrialize LEO and lunar. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[quarkstorm]

The first logical step in my view is asteroid mining, asteroids have the advantage of low escape velocities compared to planets. Since launch costs are one of the major costs; to me this gives asteroids the strongest economic case.

 

[qso1]

True, but it would probably come only after some type of experience is gained in LEO. Experience such as developing and testing equipment that would be used to mine asteroids. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[Aetius]

I must say that I agree about starting with LEO, the Moon, and the near-Earth asteroids.<br /><br />Mars is such a rich world in terms of potential that it sells itself in terms of settlement, in my opinion. But I've gradually come to the conclusion that humanity has no future on Mars without first creating a thriving lunar and cislunar economy to pave the way.

 

[qso1]

Unfortunately, I'm a little more cynical. I don't think well get to the moon once another President is elected and more excuses for cutting NASAs budgets are brought out. Mars, forget it.<br /><br />I hope I'll be proven wrong.<br /><br />Mars is one planet that could steer us back towards space but for reasons other than industrialization. If microbiological life could be detected, maybe even brought back in sample form. The trip back would probably kill them and cause some division among scientists as to whether they were life. But there could be enough support to send humans to look at it once and for all. With any real luck, actually image squirming martian microbes under a microscope.<br /><br />From that, much of the study of said microbes probably should be conducted within their native environement and this leads to establishment of a base to support the expanding science teams on future missions to catalog, study martian microbes.<br /><br />As for the industrialization part. This will greatly depend on private enterprise having a profitable reason to establish a foothold in LEO and beyond. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[quarkstorm]

Space exploration will only progress if it can turn a profit, hence mining and other space based industries. It's unlikely that martian bacteria, however interesting, can generate any money for the people who discover or study them.

 

[qso1]

Thats true, but space mining interest is more likely to be in asteroids than in mars. Asteroids require less energy to land on or leave and there is no atmosphere to deal with. Landing craft would not require thermal protection for asteroid landings.<br /><br />The Mars life scenario is one more for scientific pursuits and because it involves the study of life, something that would capture public imagination. It would be a starting point and with a base established for researching life forms, private industry might then take an interest in Mars.<br /><br />But there again, I'm mainly speculating so its really anyones guess as to how itll all play out. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[barobrain]

I hope we do travel in space (beyond the moon), how about just to explore? I understand there needs to be a profit or some reason to go... I just wish it wasn't the only reason we would go.<br /><br />Maybe I was just born in the wrong century. I hope I do see it happen in my lifetime though.

 

[tomnackid]

Unfortunately, I'm a little more cynical. I don't think well get to the moon once another President is elected and more excuses for cutting NASAs budgets are brought out. Mars, forget it. <br />------------------------------------------------------------------------------------------<br /><br />As much as I want to see Americans on the moon again I seriously doubt that if the US doesn't do it it will never happen. Presidents, government agencies, even nations come and go. Space settlement is an issue for the long term. I think we will spend AT LEAST the next century perfecting our abilities to live and work in space before we see any real, permanent settlement. Right now we are at the level of trying to explore American from europe using log rafts. Just barely possible, but hardly practical in the long run. We still as yet haven't progressed to the "viking longboat" level much less carvels, clippers or steam.

 

[Aetius]

I meant the Chinese, not the Americans. NASA will never have the resources needed to do any more than plant another flag and do some valuable scientific research. It's not in the colonization business.<br /><br />The Chinese have the money, the industrial base, and the good old Communist disregard for human life necessary for large-scale lunar and cislunar colonization.

 

[doubletruncation]

Suppose an impending threat to the Earth is discovered, and we have time to make an Orion interstellar ship of the type outlined in the above posts - who gets to go on it? It certainly doesn't seem large enough for everyone. I wonder if it really would be feasible for humans to work like mad to make such a spacecraft if the vast majority of people didn't expect to get a spot on it (or for anyone they know to get a spot on it), I suspect complete chaos, hedonism and despair would be more likely. I think we'd (humans) need to have the thing complete and in reserve somewhere before any impending catastrophe is discovered. <div class="Discussion_UserSignature"> </div>

 

[doubletruncation]

<font color="yellow">qso1:<br />Mars is one planet that could steer us back towards space but for reasons other than industrialization. If microbiological life could be detected, maybe even brought back in sample form.</font><br /><br />I think the possibility of native life on mars is probably more a hindrance for humans going there than a motivation. Once anything biological from the Earth is put on that planet any discoveries of microbial life will always be viewed with skepticism. <div class="Discussion_UserSignature"> </div>

 

[qso1]

That is certainly true but one can only hope that we can determine which is martian and which is earthly. Otherwise, how will we ever be able to know if simple life forms exist on other worlds beyond the shadow of reasonable doubt. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[vogon13]

Depends on the specific threat. I think. Big undeflectable stellar core fragment headed for collision with earth in 500 years would allow for a series of craft to be built. I suspect society wouldn't fall apart till last generation of folks are staring at the damn thing.<br /><br />Enough lead time, and you can send several craft out and cut birthrate last 100 years so there is hardly any one still on earth for the big splat.<br /><br /><br /><br />Now if they decide the sun is qoing to blow up July 26, 2009 . . . . . . . .<br /><br /><br /><img src="/images/icons/tongue.gif" /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[doubletruncation]

<font color="yellow">That is certainly true but one can only hope that we can determine which is martian and which is earthly. Otherwise, how will we ever be able to know if simple life forms exist on other worlds beyond the shadow of reasonable doubt.</font><br /><br />I just mention this since I have heard a lot of scientists use this as an argument against sending people to Mars (though mostly they are astronomers who are annoyed with the massive cuts in NASA space science to fund human exploration <img src="/images/icons/wink.gif" />). Since we do share meteorites with Mars, I think it's always possible that the Earth has already infected mars (or vice versa). I guess what we'd really like to know though is if life has managed to live on Mars without humans somehow bringing it there. (It's always possible that we've already brought something there that is capable of living on the surface, but there's really nothing we can do about that now). If upcoming mars landers include experiments to detect life, and if they show nothing at a very strong level, then I think people might be given the green light (even though there still might be life that was just not detected)... If they find something though, I could imagine people urging caution to keep the laboratory as clean as possible and then perhaps a strong emphasis would be placed on robotic study of martian life. <div class="Discussion_UserSignature"> </div>