mfb said:Via taxes: in many countries "we" do. Same goes for medical fees. The US is one of the rare exceptions of first-world countries where this is not standard.No one suggests to start construction in 2017. "Current technology" in this context means we have an idea how to build things and we had working prototypes already, which means something like TRL 5-6 - a fission reactor is fine, a fusion reactor is not. Of course such a spacecraft would need 20+ years of dedicated development, then a lot of construction work, and you probably want such a spacecraft to fly around in the solar system for at least 10 years to see if that works before it leaves the solar system.
200 years? The ISS in LEO, with its 100 KW of PV array, had something like 20 years dedicated development. The largest fission reactor ever designed for space was in the 100 KWe range, ever launched in the KWe range.mfb said:... Of course such a spacecraft would need 20+ years of dedicated development, then a lot of construction work,...
Electricity was developed over that time by the efforts of individuals across the globe, and by a system that paid handsomely for incremental improvements. There never was a central plan that imagined, 'lets start with Franklin and Faraday, so that 200 years later we'll have the modern, partially nuclear powered, electrified city'.mfb said:200 years: see electricity.
If a lot means the output of a few thousand scientists and engineers working on, say, the next Moon base, sure. An interstellar, multi-generational mission needs a million times that notion of 'a lot', and there is no means of productively coordinating the efforts of so many and so much, nor should there be absent an imminent global emergency.You can research a lot in 20 years with sufficient funding
That was not my point. We had so much progress in the last 200 years that people in 1816 could not even imagine what we can do today (e. g. because they didn't know about nuclear energy at all). Today we are closer to building a shitty but working interstellar spacecraft than the people in 1816 were to building the ISS or New Horizons, simply because we have the basic technologies that can be used for such a spacecraft : we can go to the drawing board and make concepts. You cannot make a concept of a nuclear powered spacecraft if you don't even know if atoms exist.mheslep said:Electricity was developed over that time by the efforts of individuals across the globe, and by a system that paid handsomely for incremental improvements. There never was a central plan that imagined, 'lets start with Franklin and Faraday, so that 200 years later we'll have the modern, partially nuclear powered, electrified city'.
It mainly needs things scaled up in terms of construction. Developing habitats for 1000 people is not 100 times more difficult than developing habitats for 10 people. You can take the 10-people-habitat and build it 100 times. It also needs research in many other aspects, but where does the factor 1 million come from? Sure, we don't have funding today, but with sufficient funding a huge amount of scientists could work on the open issues.mheslep said:If a lot means the output of a few thousand scientists and engineers working on, say, the next Moon base, sure. An interstellar, multi-generational mission needs a million times that notion of 'a lot'
sophiecentaur said:The interstellar project would be fun, no doubt. But the resources needed have been ignored by those in favour of it.
A much more valuable project (for everyone) would be to sort out the Earth's ecosystem.
Understood, and I disagree. In 1816 there was already of half century of lighter than air flight, a century of Newton and two and half centuries of Copernicus. Orbits were understood, that is, we knew at least where to go though the engineered means were still unknown. Now, there is no known target, nor a means to communicate effectively with an interstellar ship and learn anything from one, even unmanned, over a gap of hundreds or thousands of years of message time. Experiment and iteration based on outcomes is the main way human knowledge currently progresses, perhaps the only way, and without a FTL work-around that kind of progress is not feasible with interstellar travel.mfb said:Today we are closer to building a shitty but working interstellar spacecraft than the people in 1816 were to building the ISS or New Horizons,
mheslep said:Now, there is no known target
nor a means to communicate effectively with an interstellar ship and learn anything from one, even unmanned, over a gap of hundreds or thousands of years of message time.
Experiment and iteration based on outcomes is the main way human knowledge currently progresses
What you describe might well suffice for some kind of long term, man-made, orbital artificial habitat. A large can in space. Though adequate, it would be inevitably inferior to the protections and resources offered by its planet of origin. The space-can idea however has little to do with interstellar anything, as there is no prospect of a habitable destination, no means for effective IS communication, no means for IS energy production at that scale and time period, ...nikkkom said:...Such as reliable closed loop life support systems, industrial production in space (first for low-tech materials - metals, fuel, oxygen and other gases, then for almost everything), medical research and countermeasures against radiation and zero-g.
mheslep said:What you describe might well suffice for some kind of long term, man-made, orbital artificial habitat. A large can in space. Though adequate, it would be inevitably inferior to the protections and resources offered by its planet of origin.
The space-can idea however has little to do with interstellar anything
What you described ( reliable closed loop life support systems, industrial production in space ..., medical research and countermeasures against radiation and zero-g.) is not an interstellar ship, but a long term, self-sufficient space based habitat, as long as it remains within a couple AUs of the sun for power. No destination, no means of self-contained power source, no fractional speed of light propulsion. As such, what's the point?nikkkom said:How "planet of origin" is even relevant to the needs of an interstellar ship? Interstellar ship is not a planet.
I don't follow how visiting solar system based KBO's with unmanned spacecraft has any relevance to interstellar travel to objects 10^6 more distant.nikkkom said:True. And we will have plenty of experiment and iteration building ships and flying to ever more distant KBOs. Sedna is at 76 AU at perihelion. More distant KBOs will be found.
mheslep said:I don't follow how visiting solar system based KBO's with unmanned spacecraft has any relevance to interstellar travel to objects 10^6 more distant.
mheslep said:What you described ( reliable closed loop life support systems, industrial production in space ..., medical research and countermeasures against radiation and zero-g.) is not an interstellar ship, but a long term, self-sufficient space based habitat
Why would be the point of manning such a craft, a flying nuclear reactor with a pilot for some 20 years, which must return over similar period, in order to investigate the geology of some space rocks?nikkkom said:Try "visiting solar system based KBO's with manned spacecraft "
mheslep said:Why would be the point of manning such a craft, a flying nuclear reactor with a pilot for some 20 years, which must return over similar period
To go to a known destination with plenty of resources and live. Well worth the risks. Cook, the discoverer, returned.nikkkom said:What was the reason people sailed to Australia?
This is still about KBOs? You imagine manned 20 year suicide missions to distant space rocks and ice-balls?And where did I say anything about returning?
mheslep said:To go to a known destination with plenty of resources and live. Well worth the risks.
This is still about KBOs? You imagine manned 20 year suicide missions to distant space rocks and ice-balls?
I don't think they are mutually exclusive. I think they are closely linked. Sure, you don't have a complex climate in a spacecraft , but understanding the flow of various chemicals is necessary both for Earth and the spacecraft . A spacecraft would have to be a completely closed ecosystem, and we have an example of such a system here on Earth, with many nearly closed subsystems.sophiecentaur said:The interstellar project would be fun, no doubt. But the resources needed have been ignored by those in favour of it.
A much more valuable project (for everyone) would be to sort out the Earth's ecosystem. Why is this such a poor relation project? Not boy racer enough?
The two projects are so demanding as to be mutually exclusive, imo.
Tell that people who get a hurricane every other year. Or every year in a few decades. Or people living in places that will be deserts soon. If "we" shift away from fossil fuels, why does the global oil and coal consumption go up every year?nikkkom said:From where I sit, Earth ecosystem is fine as it is. And we shift from fossil fuels to renewables already.
Orbits were understood, sure - trajectories to other stars are understood today as well. That is not the point.mheslep said:In 1816 there was already of half century of lighter than air flight, a century of Newton and two and half centuries of Copernicus. Orbits were understood, that is, we knew at least where to go though the engineered means were still unknown.
I think they would have to be because of the extreme commitment of resources / money for either. The priority would clearly be in favour of an Earth Repair project - for the whole population, rather than a project which would benefit only the crew. I am assuming that any useful final destination would be too far for useful communications (bandwidth limited) and certainly for any useful trade or importing of materials. It is far too short sighted to talk in terms of life support on a ship of some kind. It would be essential to think in terms of a long term living environment on a suitable planet. All the technology for maintaining Earth's ecosystems would be needed PLUS the (over trivialised) terraforming that would be needed.mfb said:I don't think they are mutually exclusive.
sophiecentaur said:I think they would have to be because of the extreme commitment of resources / money for either. The priority would clearly be in favour of an Earth Repair project
Interstellar travel is a certainty if we do not vanishes as a specie. We just do not have the right technology yet. Right now it is science fiction, but science fiction is fertile and creative for ideas and sometimes leads the path to technological advances. DaVincy thaguht of submarines before they've ever existed. So does creativity leads science or science leads creativity?bugatti79 said:Hi Folks,
What is your opinion on this article? It suggest that interstellar travel is a fantasy.
http://www.scientificamerican.com/article/interstellar-travel-as-delusional-fantasy-excerpt/#
Yet, I read articles about institutions like NASA investing in various conceptual propulsion systems.
Are they wasting their time?
Regards
B
Creativity leads science, because without any ideas, there wouldn't be innovations and improvements. Interstellar traveling is an achievement. So there is a bunch of ideas coming out of it...as fiction, so delusion...it is a process...we just need to decide how much ressources we put into it...Ugo said:Interstellar travel is a certainty if we do not vanishes as a specie. We just do not have the right technology yet. Right now it is science fiction, but science fiction is fertile and creative for ideas and sometimes leads the path to technological advances. DaVincy thaguht of submarines before they've ever existed. So does creativity leads science or science leads creativity?
Yes, for a space telescope. The point is that we have no idea about any planets that would support a landing via suitable gravity, surface, and atmosphere, much less habitable planets. In that sense for interstellar travel we are still pre-Copernican. For would be space travelers who need a habitable planet for their grand children after 4-500 yrs in space, else they die in space, and the odds are hugely against that one planet supporting life? No thanks.mfb said:The planet around Proxima Centauri is an interesting target,...
New solar stops quite quickly, as predicted by all the serious studies, after 10% share of load or so. Germany reached 9% generation share by solar with a large feed in tariff, and has slowed to 2% new solar capacity per year, with 0.8% per year required to replace decay.nikkkom said:What "extreme money" are you talking about? Solar doubles every 2.5 years. Even if this trend slows down,
.more than half of all generation will be solar
Not so. Unsubsidized interrmittent power only slightly competes with the build of new dispatchable or baseload plants, as these plants *must* be built to supply a reliable grid. Germany continues to build new coal; California continues to build new natural gas plants. So a decision to build new solar competes with the marginal cost only, i.e. whether or not to *run* these existing plants when solar is available, which costs 2 or 3 cents per kwh. When the solar share is quite low, utility solar (not rooftop) can be competitive given some slight excess in the existing grid capacity which solar can retire.And most importantly, solar *no longer needs subsidies* - solar power stations are competitive with other generation even today, and ...
mheslep said:New solar stops quite quickly, as predicted by all the serious studies, after 10% share of load or so. Germany reached 9% generation share by solar with a large feed in tariff, and has slowed to 2% new solar capacity per year, with 0.8% per year required to replace decay.
Impossible without either i) storage
Currently there are no utility battery storage projects anywhere in the world, nor any planned, that could backup a medium sized thermal plant for a half day.
There's only one way with current technology to retire a fossile fuel based grid, proven several times over: nuclear power.
I totally disagree. You would need to be totally backs to the wall to swap living on Earth for the Risk and the boredom of a long (years and years or even generations) space voyage with no certainty of a good destination.DrStupid said:It would need a really, really good reason not to leave.
What sort of magic law says that we should not expect to vanish at some point? The same sort of reasoning that makes some people believe in everlasting (personal) life, I guess. Very comforting for those who need it but a totally groundless assumption.Ugo said:Interstellar travel is a certainty if we do not vanishes as a specie.
It is never about having the money - it is about the will to spend it. Anyway, as I mentioned before: a lot of research would help both the Earth and a future spacecraft , and a lot of research for a spacecraft would help people on Earth as well. Research on terraforming (which is optional) has applications in the solar system as well.sophiecentaur said:I think they would have to be because of the extreme commitment of resources / money for either. The priority would clearly be in favour of an Earth Repair project - for the whole population, rather than a project which would benefit only the crew. I am assuming that any useful final destination would be too far for useful communications (bandwidth limited) and certainly for any useful trade or importing of materials. It is far too short sighted to talk in terms of life support on a ship of some kind. It would be essential to think in terms of a long term living environment on a suitable planet. All the technology for maintaining Earth's ecosystems would be needed PLUS the (over trivialised) terraforming that would be needed.
There is far more involved than just getting a number of people to some destination hundreds of light years away. Why is that task the only one that is considered by the enthusiasts?
The planet around Proxima Centauri has a suitable gravity. We can probably work with its surface. It does not need to have a great atmosphere. The spacecraft which arrives there is nearly self-sufficient. Every planet with a solid or liquid surface and reasonable gravity is better than the working spacecraft . We know already that the planet around Proxima Centauri has this.mheslep said:Yes, for a space telescope. The point is that we have no idea about any planets that would support a landing via suitable gravity, surface, and atmosphere, much less habitable planets.
I like your optimism, but (a) it only doubles 2-3 years in countries with a small fraction of solar power, (b) increasing the fraction above ~15% will lead to huge stability issues with the power grid as (c) we don't have an affordable large-scale storage solution yet (you still need power when it is cloudy, for example). Which also means "no longer needs subsidies" is misleading: it needs regulations giving it priority over conventional power plants, which increases their price in times when the sun does not shine - we pay for it, just at different places. And even with this huge advantage of not caring about the time of production, it is not yet competitive in many places where power is needed. Germany for example pays several billion dollars of direct subsidies every year for its ~10% solar energy share, estimates about the total subsidies (spent plus future commitments) are ~250 billions.nikkkom said:What "extreme money" are you talking about? Solar doubles every 2.5 years. Even if this trend slows down, in 20-30 years, more than half of all generation will be solar. And most importantly, solar *no longer needs subsidies* - solar power stations are competitive with other generation even today, and will get even better with economies of scale. From now on, it will grow "automatically", without special efforts, by virtue of being a good investment. In fact, I have hard time imagining how anyone can possibly stop it now.
It is much better than coal if you include the costs induced by the exhaust of coal power plants. And then there is still the CO2 which leads to huge indirect costs.nikkkom said:Nuclear is not competitive with coal
Oh come on. Coal power plants emit more activity than nuclear power plants. Which is completely irrelevant compared to other damages done anyway.will stop dousing us with Cs-137
sophiecentaur said:I totally disagree. You would need to be totally backs to the wall to swap living on Earth for the Risk and the boredom of a long (years and years or even generations) space voyage with no certainty of a good destination.
The potential 'Spacers' on this thread seem to think that providing an near enough Earthlike existence at the destination would somehow be easier than sorting out the Earth.
mfb said:>> Nuclear is not competitive with coal
It is much better than coal if you include the costs induced by the exhaust of coal power plants. And then there is still the CO2 which leads to huge indirect costs.