100 year starship

[wiggin]

http://www.100yss.org/

Certainly cool, but probably a waste of DARPA's money. What do you guys think? Will this kind of very early 'seeding' actually produce any results? It seems so remarkably distant as to be irrelevant.

[LittleFuzzy]

http://www.100yss.org/

Certainly cool, but probably a waste of DARPA's money. What do you guys think? Will this kind of very early 'seeding' actually produce any results? It seems so remarkably distant as to be irrelevant.

Can it produce results? Absolutely. See "internet." Will it do so in this case? No telling, but enabling that sort of thing is one of DARPA's primary missions, so. . .

[wiggin]

Can it produce results? Absolutely. See "internet." Will it do so in this case? No telling, but enabling that sort of thing is one of DARPA's primary missions, so. . .

Oh, please, the internet was completely different from this. I'm all in favor of DARPA funding high risk projects that don't quite have the technology to work yet. Plenty of very impressive things have come out of such funding, and I'm all in favor of it.

Yet this is clearly far more speculative - they're not funding research or technology yet, they're funding studies to figure out how they should think about funding research and technology. The relevant technology is so far in the future as to be not just risky but essentially a complete shot in the dark.

[LittleFuzzy]

Oh, please, the internet was completely different from this. I'm all in favor of DARPA funding high risk projects that don't quite have the technology to work yet. Plenty of very impressive things have come out of such funding, and I'm all in favor of it.

Yet this is clearly far more speculative - they're not funding research or technology yet, they're funding studies to figure out how they should think about funding research and technology. The relevant technology is so far in the future as to be not just risky but essentially a complete shot in the dark.

I think those hindsight-colored glasses of yours are giving you an inaccurate picture of the state of IT in the early to mid 60s and the uncertainty of its future.

[wiggin]

From the basic idea of a packet switching network to a working prototype was less than a decade. The technology behind ARPANET was not particularly revolutionary, it just hadn't been implemented yet.

We're talking about interstellar travel, when our very farthest probes have barely hit the outside of our solar system.

[LittleFuzzy]

From the basic idea of a packet switching network to a working prototype was less than a decade. The technology behind ARPANET was not particularly revolutionary, it just hadn't been implemented yet.

We're talking about interstellar travel, when our very farthest probes have barely hit the outside of our solar system.

I'm sorry, I thought we were already quite clear that the direct 'goal' was not the real purpose, anymore than this modern internet was what figures like Bob Taylor or Licklider imagined.

[EyeKhan]

Well, this is interesting stuff to study. Who knows what might come out of it. It can't be that expensive, so why not generate some thoughts, ideas, plans, and maybe innovations?

This endeavor will require an understanding of questions such as: how do organizations evolve and maintain focus and momentum for 100 years or more; what models have supported long term technology development; what resources and financial structures have initiated and sustained prior settlements of "new worlds?"

The first two questions could be useful to answer entirely outside a starship project. The last one is intersting from a historical perspective and would easily be of importance to anyone thinking about Moon or Mars colonization or even Asteroid mining.

[Nessus]

We're talking about interstellar travel, when our very farthest probes have barely hit the outside of our solar system.

You make it sound such a small thing.

[wiggin]

I'm sorry, I thought we were already quite clear that the direct 'goal' was not the real purpose, anymore than this modern internet was what figures like Bob Taylor or Licklider imagined.

As I understand, the goal is to have interstellar capability within 100 years, not an interstellar civilization. That's pretty ambitious and frankly unlikely.

Well, this is interesting stuff to study. Who knows what might come out of it. It can't be that expensive, so why not generate some thoughts, ideas, plans, and maybe innovations?

The first two questions could be useful to answer entirely outside a starship project. The last one is intersting from a historical perspective and would easily be of importance to anyone thinking about Moon or Mars colonization or even Asteroid mining.

There are better ways to study those questions, EK... and really? Moon/Mars colonization? That's almost certain to be a huge money losing proposition. The asteroid mining idea might pay off (big emphasis on the might), but extraterrestrial colonization is unlikely to be worth it short of something like wormhole technology.

You make it sound such a small thing.

On the one hand, it's impressive - a species of essentially apes has managed to put artificial devices unimaginably far away from their home planet. Yet these devices are essentially useless hunks of metal now, and they're only a tiny fraction of the distance to the next item of interest.

I have a lot of respect for NASA and their associated space endeavors - hell, I love SF novels with the best of them. But from a hard-headed look at what's actually worthwhile, I can't see interstellar travel being a reality or useful anytime in the foreseeable future absent some truly remarkable technological developments. Why waste time (and money) aiming for something so remote?

[Nessus]

A man needs only to feed, clothe and shelter himself, all other actions are folly.

Beyond that, defining the term "worthwhile" is pretty much up for grabs. If nothing else, colonizing other worlds might provide a remote chance of species survival the next time the world needs another globe-encompassing war. They'd have to hope that they'd be able to return to Earth relatively soon, of course, as a self-sufficient colony seems like an unlikely prospect.

Anyway, my personal view (some of the time) is that mankind should be a tool for science, not the other way around. I suspect you'll find even more disapproval for this idea than you'd find support for the first sentence of my post.

[Loki]

What's the purpose of science?

[Nessus]

As it, as a broad term, does not directly serve feeding, clothing and sheltering people (segments of it do, but that's irrelevant to your question), it is devoid of purpose and a completely futile activity.

[Loki]

Is it meant to benefit humanity in any way? Other than finding out answers to questions that you don't think they should act upon?

[Nessus]

Is it meant to benefit humanity in any way?

I am unsure how to further clarify myself on this particular issue.

Other than finding out answers to questions that you don't think they should act upon?

I do not understand what you mean by "don't think they should act upon".

[Loki]

I.E. Use the science to benefit humanity.

[Nessus]

I'm still not getting what you're after, maybe you could try to explain?

Edit:

Here are my problems vis a vis comprehension. You use nebulous terms such as "benefiting humanity" without defining them. The only objective benefit-ings for an individual are the three I listed, food shelter and clothing, beyond those we start getting into trouble. And I am utterly unsure we could hope to define any objective benefits to humanity as a lump whole. We could probably agree on some benefits for all of humanity, but in doing so we would need to agree to some number of subjective axioms, which a differently minded person may want to question. So I am unsure what question you are posing to me, exactly. On the matter of nutrition, shelter and clothing I already explained that science as a whole is largely a purposeless and meaningless pursuit; if you have some favourite candidates for humanity-wide benefits, we can discuss each one specifically but you'll have to list them first.

[Loki]

You seem to be of the view that we should promote science for the sake of promoting science, which is to say that we shouldn't expect to have our lives improved as a result. I.E. We should research A because it will allow us to research B, which would allow to us research C, etc. We shouldn't research A in order to help us produce something that benefits humanity, like some technology or medicine.

[Nessus]

Please see the edit I made to my post while you were posting; I'm sorry I'm so impatient

[Loki]

I never said something must benefit all of humanity; just that it benefits some of it. And do you really think that the internet, phones, TVs, cars, railroads, etc. don't benefit humanity?

[LittleFuzzy]

As I understand, the goal is to have interstellar capability within 100 years, not an interstellar civilization. That's pretty ambitious and frankly unlikely.

You are getting way to hung up on this term "interstellar."

[Nessus]

I never said something must benefit all of humanity; just that it benefits some of it. And do you really think that the internet, phones, TVs, cars, railroads, etc. don't benefit humanity?

As net wholes, do they benefit humanity? I'm not willing to guess either way without data. And I'm skeptical comprehensive studies have been done, or can be done with the current level of science funding. And the process you described in

I.E. We should research A because it will allow us to research B, which would allow to us research C, etc. We shouldn't research A in order to help us produce something that benefits humanity, like some technology or medicine.

could arguably benefit some of humanity; can you propose some minimum percentage of humanity that has to experience (or think it experiences) a benefit from some action for it to be, uh, humanity-benefiting?

[Loki]

I fail to see why there needs to be any threshold. Either science is intended at some point to have practical application or it does not.

[Nessus]

Hold up there bucko, you just shifted the goal posts by some stadiums. Since when do practical applications alone count as beneficial? This is what I meant by subjective axioms!

[Loki]

Hold up there bucko, you just shifted the goal posts by some stadiums. Since when do practical applications alone count as beneficial? This is what I meant by subjective axioms!

Erm, what's the purpose of practical application?

[Nessus]

Besides nutrition, shelter and clothing for human beings? Arbitrarily definable. And that ignores the other side of the equation; what is 'benefit', exactly? If not nutrition, shelter and clothing alone.

[Loki]

Besides nutrition, shelter and clothing for human beings? Arbitrarily definable. And that ignores the other side of the equation; what is 'benefit', exactly? If not nutrition, shelter and clothing alone.

So should anyone bother with the application unless it directly relates to nutrition, shelter, or clothing?

[Nessus]

So should anyone bother with the application unless it directly relates to nutrition, shelter, or clothing?

You tell me, you're the one who wanted benefits!

(Get it?)

[Loki]

I'd rather stay friends.

[EyeKhan]

As I understand, the goal is to have interstellar capability within 100 years, not an interstellar civilization. That's pretty ambitious and frankly unlikely.

That's actually not the goal, as far as I what I read. The goal is to spur innovative, out of box thinking on these topics with the hope that if the unlikley goal is never reached, at least useful spinoffs would result.

There are better ways to study those questions, EK... and really? Moon/Mars colonization? That's almost certain to be a huge money losing proposition. The asteroid mining idea might pay off (big emphasis on the might), but extraterrestrial colonization is unlikely to be worth it short of something like wormhole technology.

#1. Suggest a better way and explain why its better. #2. Whether a profit is made is not always the measure of a good idea. #3. Asteroid mining almost certainly would pay off. Especiailly if there were heavy engagement of robotics, as was suggested by DW. The time and expense, and the extreme consequences of error, for moving an asteroid in local orbit likely would nix it. But insitu? The payoff would likely be gargantuan and the expense merely rather large.

[Draco]

A Fusion Thruster for Space Travel
Clean, highly energetic reaction delivers a lot of drive from a drop of fuel

28 June 2011—Designers of satellites obsess about how little fuel their creations are able to carry into space. So the propulsion method they choose for maneuvers such as orbital transfers has to deliver a lot for a little.

Now a NASA engineer has come up with a new way to fling satellites through space on mere grams of fuel, tens of times as efficiently as today’s best space probe thrusters. The answer, he says, is fusion. You might be thinking, "Fusion? Really?" But it’s not as far-fetched as it sounds at first blush. The engineer delivered the details today at the IEEE Symposium on Fusion Engineering in Chicago.

Instead of using deuterium and tritium as the fuel stocks, the new motor extracts energy from boron fuel. Using boron, an "aneutronic" fuel, yields several advantages over conventional nuclear fusion. Aneutronic fusion, in which neutrons represent less than 1 percent of the energy-carrying particles that are the result of a reaction, is easier to manage. "Neutrons are problematic, because for one thing they’re difficult to harness," says John J. Chapman, the concept’s inventor and a physicist and electronics engineer at NASA’s Langley Research Center, in Virginia. To make use of neutrons, "you need an absorbing wall that converts the kinetic energy of the particles to thermal energy," he says. "In effect, all you’ve got is a fancy heat engine, with all its resultant losses and limitations."

In Chapman’s aneutronic fusion reactor scheme, a commercially available benchtop laser starts the reaction. A beam with energy on the order of 2 x 10¹⁸ watts per square centimeter, pulse frequencies up to 75 megahertz, and wavelengths between 1 and 10 micrometers is aimed at a two-layer, 20-centimeter-diameter target.

The first layer is a 5- to 10-µm-thick sheet of conductive metal foil. It responds to the teravolt-per-meter electric field created by the laser pulse by "acting as a de facto proton accelerator," says Chapman. The electric field releases a shower of highly energetic electrons from the foil, leaving behind a tremendous net positive charge. The result is a massive self-repulsive force between the protons that causes the metal material to explode. The explosion accelerates protons in the direction of the target’s second layer, a film of boron-11.
Illustration: NASA Langley Research Center
Click on image for a larger view.


There, a complicated nuclear dance begins. The protons (which carry energy on the order of roughly 163 kiloelectron volts) strike boron nuclei to form excited carbon nuclei. The carbons immediately decay, each into a helium-4 nucleus (an alpha particle) and a beryllium nucleus. Almost instantaneously, the beryllium nuclei decay, with each one breaking into two more alpha particles. So for each proton-boron pair that reacts, you get three alpha particles, each with a kinetic energy of 2.9 megaelectron volts.
Illustration: NASA Langley Research Center

Electromagnetic forces push the target and the alpha particles in the opposite directions, and the particles exit the spacecraft through a nozzle, providing the vehicle’s thrust. Each pulse of the laser should generate roughly 100 000 particles, making the method tremendously efficient, says Chapman. And according to his calculations, improvements in short-pulse laser systems could make this form of thruster more than 40 times as efficient as even the best of today’s ionic propulsion systems that push spacecraft around. The specific power of the proton-triggered boron fuel would be so great that a mere mole of it (11 grams) would yield roughly 300 megawatts of power. (According to Chapman, using this aneutronic fusion technique with helium-3 isotopes would yield 493 MW per mole. But boron is a more attractive fuel source because it is abundant on Earth and helium-3 is scarce.)

Another big advantage of fusion space propulsion, Chapman claims, is that some of the energy can be converted into electricity to power a spacecraft’s onboard control systems. "A traveling wave tube—basically an inverse klystron—captures most of the particles’ flux kinetic energy and efficiently converts it into electrical energy," says Chapman. The process, he says, is 60 to 70 percent efficient.

The NASA engineer acknowledges that this collection of ideas is still a long way from being a practical device. For example, losses from the alpha particles striking the walls of the exhaust nozzle or each other lower the net power output. Figuring out how to control the particles’ path is an important consideration.

Asked how long it will be before his fusion reactor is pushing spacecraft toward Mars, Chapman acknowledges that a decade of work might be required before that happens. "It takes teamwork to get something to the point where you put it in space," he says. His aim so far is "to get the idea out so other minds can begin thinking about it."

Something related to the topic http://spectrum.ieee.org/aerospace/s...space-travel/0