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MacMcK1957
Posts: 2,223
Registered: ‎07-25-2011

Re: Is star travel practical in theory now? Some Food for Thought.


deesy58 wrote:

Omnigeek wrote:

deesy58 wrote:

ManuelGarcia wrote:

I should have said "impossible in a human lifetime". The following is in Freeman Dyson's 1968 paper "Interstellar Transport."  Using 1 megaton fusion bombs, an Orion type spacecraft would require 30,000,000 bombs to achive an average acceleration of 0.0003g, giving it a maximum velocity of 0.0033c.  It would take 1,330 years to reach Alpha Centauri at a cost of $3.67 Trillion. The main reason is that the ship requires a 5,000,000 ton copper hemisphere to withstand the 1 megaton nuclear explosion and requires about 2 minutes for it to cool off enough for the next explosion.

This is why project Icarus' design depends on small fusion explosions to reduce the mass of the pusher plate, and reduce the time between explosions so that it can get to 0.1c speed and get to Alpha Centauri in about 50 years. But as I said until someone figures how to create small fusion explosions, Icarus can't be build.


Thanks for the great exposition on this subject.  It provides an even more convincing argument that the idea is reminiscent of 1930's Science Fiction. 


Hmmm ... you make some remarkably broad assertions about the non-viability of a project you aren't familiar with.  The problems with Project Icarus were political and financial -- by and large, the math and engineering work out.  It's still not something that many people would advocate because of the nuclear aspect but you really should look at the force equation before you dogmatically assert any passenger would be squashed like a bug.

 

One of the big problems with the concept of generational ships is that we haven't yet licked the self-sufficient ecosystem problem.  The Biosphere II experiment of the 90s was designed to help understand the problem and gauge our abilities -- as I recall, they had to supplement oxygen in the dome as they had a severe unexpected drop in available oxygen.  Generational ships may yet happen some day but we have a lot more to learn before they become a reality.

 

TANSTAAFL.


But if you look at the title of this thread, it says NOW.  Is it practicalNOW?

 

Everything posted on this thread that has also been supported with facts seems to indicate that it is not feasible now, including your observation about Biosphere II. 

Like the perpetual motion machine that many believed would be only a matter of time, some things might never come to pass. 


The only person claiming it's practical now is the OP in attempting to promote his book.  Don't think anyone bought his argument, or for that matter his book.

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WONK
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Re: Is star travel practical in theory now? Some Food for Thought.

<But if you look at the title of this thread, it says NOW. Is it practicalNOW?>

 

It depends on how you define practical and now.  If some event became know that would affect life on earth, it would be possible to start building colony size or generational space ships today.  It would take a decade or two to finish the production of the ships.  But the requirements for this type of ship are within our technology.  It would just take the acknowledged need to do it and the money to fund it.  With a major extinction event both the need and the money would become available. 

 

Using today's technology it is possible to move asteroids.  Both commercial and non-comercial projects are on the books today to do this.  A closed life support system is possible with today's technology as well.  You just need to select the correct biomass and that just requires a better analysis of what we currently know.  The veolocity using what is available today for the ships would be slow, but you could leave the solar system.  Possibly a bigger problem than the mechanics of building the ships would be finding a viable location to send them to but with the prediction that this year earth type planets will be mapped using the systems we are currently using that problem would be solved before the ships are finished.

 

A good way to think about this is to consider that with today's technology we could start the construction of colonies on the Moon or Mars.  It would take time to finish the colonies but we could start building them today if we had a sustained funding source.  Remember that there is currently a start-up company considering the mining of asteroids.  This indicates that commercially we are close to having the technology that will permit mining of space for a profit.  The key aspect is a stable funding source for these types of multi-year projects.

 

Near light speed ships need a paradigm shift before their construction.

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deesy58
Posts: 2,486
Registered: ‎01-22-2012

Re: Is star travel practical in theory now? Some Food for Thought.


MacMcK1957 wrote:

The only person claiming it's practical now is the OP in attempting to promote his book.  Don't think anyone bought his argument, or for that matter his book.

I think you might be mistaken, Mac.  WONK seems to believe that it is practical now.

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ManuelGarcia
Posts: 83
Registered: ‎12-25-2009

Re: Is star travel practical in theory now? Some Food for Thought.


WONK wrote:

<But if you look at the title of this thread, it says NOW. Is it practicalNOW?>

 

It depends on how you define practical and now.  If some event became know that would affect life on earth, it would be possible to start building colony size or generational space ships today.  It would take a decade or two to finish the production of the ships.  But the requirements for this type of ship are within our technology.  It would just take the acknowledged need to do it and the money to fund it.  With a major extinction event both the need and the money would become available. 

 



If a major extinction event was predicted, I would prefer resources be used to create space colonies, on Moon, Mars and in Space.  No matter what only a small fraction of the population could be saved, but if generation ships were built, they would require extra resources for propellant, and fuel that otherwise could be used for the colonies. Also a generation ship would be on its own for resources.  Space colonies would have access to the resources in asteroids, Moon and Mars to help with overcoming problems with the life support systems. 

In fact I think if a extinction event happened and humans moved into local space, interstellar travel would be delayed for centuries because almost all resources would be required to keep as many people alive as possible.

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deesy58
Posts: 2,486
Registered: ‎01-22-2012

Re: Is star travel practical in theory now? Some Food for Thought.


ManuelGarcia wrote:

WONK wrote:

<But if you look at the title of this thread, it says NOW. Is it practicalNOW?>

 

It depends on how you define practical and now.  If some event became know that would affect life on earth, it would be possible to start building colony size or generational space ships today.  It would take a decade or two to finish the production of the ships.  But the requirements for this type of ship are within our technology.  It would just take the acknowledged need to do it and the money to fund it.  With a major extinction event both the need and the money would become available. 

 



If a major extinction event was predicted, I would prefer resources be used to create space colonies, on Moon, Mars and in Space.  No matter what only a small fraction of the population could be saved, but if generation ships were built, they would require extra resources for propellant, and fuel that otherwise could be used for the colonies. Also a generation ship would be on its own for resources.  Space colonies would have access to the resources in asteroids, Moon and Mars to help with overcoming problems with the life support systems. 

In fact I think if a extinction event happened and humans moved into local space, interstellar travel would be delayed for centuries because almost all resources would be required to keep as many people alive as possible.


Doesn't our experience at Biosphere II indicate that we are not, yet, ready to support human life off the planet, regardless of exactly where, at this time (now)?  Isn't the problem of life support still largely an unsolved one?  Assuming we had a power plant capable of taking us wherever we wanted to go, how would we remain alive for any protracted length of time in an airless environment lacking in liquid water?

I believe that this problem is a long way from being solved.   

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ManuelGarcia
Posts: 83
Registered: ‎12-25-2009

Re: Is star travel practical in theory now? Some Food for Thought.


deesy58 wrote:



Doesn't our experience at Biosphere II indicate that we are not, yet, ready to support human life off the planet, regardless of exactly where, at this time (now)?  Isn't the problem of life support still largely an unsolved one?  Assuming we had a power plant capable of taking us wherever we wanted to go, how would we remain alive for any protracted length of time in an airless environment lacking in liquid water?

I believe that this problem is a long way from being solved.   


Which is why I think generation ships would not be a viable solution to an extinction event, because they would have to be fully closed systems.

 

But space colonies would have access to other resources.  There is evidence of lunar polar water ice.  There may be water on Mars, comets have a large amount of ice. Some or all of these could be used to offset loses of water and oxygen. In fact without a extinction event these resources would be useful for space colonies.  That way colonies wouldn't have be started with fully closed systems, but as more information is learned they could get closer and closer to fully closed systems.

 

Even if a propulsion system is designed that allows a trip to the stars in decades instead of centuries the life support system would still have to be better than what we have done so far. But learning via space colonies should make one possible. 

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deesy58
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Re: Is star travel practical in theory now? Some Food for Thought.

[ Edited ]

ManuelGarcia wrote:

deesy58 wrote:



Doesn't our experience at Biosphere II indicate that we are not, yet, ready to support human life off the planet, regardless of exactly where, at this time (now)?  Isn't the problem of life support still largely an unsolved one?  Assuming we had a power plant capable of taking us wherever we wanted to go, how would we remain alive for any protracted length of time in an airless environment lacking in liquid water?

I believe that this problem is a long way from being solved.   


Which is why I think generation ships would not be a viable solution to an extinction event, because they would have to be fully closed systems.

 

But space colonies would have access to other resources.  There is evidence of lunar polar water ice.  There may be water on Mars, comets have a large amount of ice. Some or all of these could be used to offset loses of water and oxygen. In fact without a extinction event these resources would be useful for space colonies.  That way colonies wouldn't have be started with fully closed systems, but as more information is learned they could get closer and closer to fully closed systems.

 

Even if a propulsion system is designed that allows a trip to the stars in decades instead of centuries the life support system would still have to be better than what we have done so far. But learning via space colonies should make one possible. 


I have visions of a space colony on Mars or the Moon, and the colonists spending every last minute of their time finding, harvesting, transporting, melting and purifying water ice for life support.  Not to mention finding the energy required to break down molecules of water for its constituent Oxygen and Hydrogen. 

 

Am I off the mark, here?  Tell me what I am missing, and how any of this is possible with the technologies available to human beings today (now). 

 

Rough guess ... another 100 years (George W. Bush and Newt Gingrich notwithstanding :smileywink:)

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WONK
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Re: Is star travel practical in theory now? Some Food for Thought.

<Doesn't our experience at Biosphere II indicate that we are not, yet, ready to support human life off the planet, regardless of exactly where, at this time (now)?>

 

There are multiple projects that fail but are still viable.  Does the failure of a sattelite launch prove that we can't launch sattelites?  About a decade ago the first smart phone was built by Nokia, using the failure of that phone in the market (biggest drawback in the sale of that old Nokia phone was that Nokia didn't have the cult following of Apple), Apple should have said the iPhone was impossible a couple of years later.  The military regularly fails on R and D projects but frequently the failures give more data then the successes and the products are working in the next build the same year.  Biosphere II wasn't a complete success but it showed where things went wrong.  We live on a closed biosphere.  We know a lot about bio cycles.  What it will take is fine tuning the systems and that is definitly possible with today's technology and knowledge.  Biosphere II was just a single experiment.  You might have a point if there were a dozen big experiments that all failed spectacularly but I know no one who claims the technology isn't there--it is putting together the right combination of biological cycles.  And no one has completely tested the most probable systems in space travel which entail significant mechanical adjucts to the biocycles.

 

The technology is here it is the will and funding to build the systems needed that are not.

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deesy58
Posts: 2,486
Registered: ‎01-22-2012

Re: Is star travel practical in theory now? Some Food for Thought.


WONK wrote:

<Doesn't our experience at Biosphere II indicate that we are not, yet, ready to support human life off the planet, regardless of exactly where, at this time (now)?>

 

There are multiple projects that fail but are still viable.  Does the failure of a sattelite launch prove that we can't launch sattelites?  About a decade ago the first smart phone was built by Nokia, using the failure of that phone in the market (biggest drawback in the sale of that old Nokia phone was that Nokia didn't have the cult following of Apple), Apple should have said the iPhone was impossible a couple of years later.  The military regularly fails on R and D projects but frequently the failures give more data then the successes and the products are working in the next build the same year.  Biosphere II wasn't a complete success but it showed where things went wrong.  We live on a closed biosphere.  We know a lot about bio cycles.  What it will take is fine tuning the systems and that is definitly possible with today's technology and knowledge.  Biosphere II was just a single experiment.  You might have a point if there were a dozen big experiments that all failed spectacularly but I know no one who claims the technology isn't there--it is putting together the right combination of biological cycles.  And no one has completely tested the most probable systems in space travel which entail significant mechanical adjucts to the biocycles.

 

The technology is here it is the will and funding to build the systems needed that are not.


I believe that your analogy breaks down.  If a particular launch system is not able to launch a satellite, would you continue to use it without introducing any corrections or improvements?

 

The Biosphere II complex is still right where it has always been in Arizona, right?  If the earlier experiments failed, and if we know why they failed, and if we have the technology to repeat the experiments in a more successful manner, then why aren't we doing so?  Do we really believe that we can put people into space for long periods with nothing more than faith in technology to help them survive?  Might it be better to possess a modicum of knowledge and experience with surviving in an extremely hostile environment for extended periods before making such an attempt? 

 

I think we're not there, yet.  You believe we are.  I further believe that this might be a much knottier problem than the science fiction novels portray.  I guess if we live long enough, we will learn who is correct.  :smileywink:

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JimJoe
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Re: Is star travel practical in theory now?

Most of the sf I've read over the past years mention faster than light, but a few mention generation ships in hollowed out asteroids. I can see why the FTL ships are more popular, butmaybe a good generation ship series would be good and interesting as well.

 

As for disturbing others... well, my experience is a significant part of humanity doesn't like changes, nor information that may counter what they learned in high school. Lots of changes, like home computers and cell phones, have happened since I graduated from high school.

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ManuelGarcia
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Registered: ‎12-25-2009
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Re: Is star travel practical in theory now? Some Food for Thought.

[ Edited ]

deesy58 wrote:

WONK wrote:

<Doesn't our experience at Biosphere II indicate that we are not, yet, ready to support human life off the planet, regardless of exactly where, at this time (now)?>

 

There are multiple projects that fail but are still viable.  Does the failure of a sattelite launch prove that we can't launch sattelites?  About a decade ago the first smart phone was built by Nokia, using the failure of that phone in the market (biggest drawback in the sale of that old Nokia phone was that Nokia didn't have the cult following of Apple), Apple should have said the iPhone was impossible a couple of years later.  The military regularly fails on R and D projects but frequently the failures give more data then the successes and the products are working in the next build the same year.  Biosphere II wasn't a complete success but it showed where things went wrong.  We live on a closed biosphere.  We know a lot about bio cycles.  What it will take is fine tuning the systems and that is definitly possible with today's technology and knowledge.  Biosphere II was just a single experiment.  You might have a point if there were a dozen big experiments that all failed spectacularly but I know no one who claims the technology isn't there--it is putting together the right combination of biological cycles.  And no one has completely tested the most probable systems in space travel which entail significant mechanical adjucts to the biocycles.

 

The technology is here it is the will and funding to build the systems needed that are not.


I believe that your analogy breaks down.  If a particular launch system is not able to launch a satellite, would you continue to use it without introducing any corrections or improvements?

 

The Biosphere II complex is still right where it has always been in Arizona, right?  If the earlier experiments failed, and if we know why they failed, and if we have the technology to repeat the experiments in a more successful manner, then why aren't we doing so?  Do we really believe that we can put people into space for long periods with nothing more than faith in technology to help them survive?  Might it be better to possess a modicum of knowledge and experience with surviving in an extremely hostile environment for extended periods before making such an attempt? 

 

I think we're not there, yet.  You believe we are.  I further believe that this might be a much knottier problem than the science fiction novels portray.  I guess if we live long enough, we will learn who is correct.  :smileywink:


I didn't mean to imply we are able to do space colonies now, heck at the moment neither NASA nor any private American company can even put a person into near Earth orbit.  I was just trying to make the point that the first colonies unlike generation ships would not have to be a fully closed systems, therefore much easier.

 

But like WONK mentioned if an extinction event was imminent, we would have incentive to quickly solve the problem. I think by space colonies, he thinks by generation ships.  Without the incentive of an extinction event we would and probably should take time to work on life support systems.

As for Biosphere II, while it still exists it has changed owners several times and and according to Wikipedia (https://en.wikipedia.org/wiki/Biosphere_2) hasn't been used for closed experiments since 1995.

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WONK
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Re: Is star travel practical in theory now? Some Food for Thought.

<I believe that your analogy breaks down.  If a particular launch system is not able to launch a satellite, would you continue to use it without introducing any corrections or improvements?>

 

That is true only if there is a flaw in the whole system.  Any new product will fail in some way and needs to be fine tuned.  If new products were perfect there would be no recalls.  How many times do car companies have recalls every year?  Do they junk the whole car or give up on driving?  Biosphere II had many small problems.  For example it frequently leaked.  Does not having enough caulking on a seam mean that the whole project doesn't work?  We use the same rockets that failed in the past mutliple times during many military and civilian projects but we seldom scrap the whole rocket.  We find the small part that isn't working and send up the rocket again.

 

< If the earlier experiments failed, and if we know why they failed, and if we have the technology to repeat the experiments in a more successful manner, then why aren't we doing so?>

 

The answer is money.  It takes a lot of money to run an isolated system large enough to support a number of people and there are few sources of funding for that.  You will see the money for this type of research appear when a few commercial mining projects locate minerals that are economically viable.  The R&D funders would be doing more basic research now if most thought that habitats are big bottlenecks for space mining.  Or the time line needed to produce the habitats is much shorter than the time line needed to find the ideal locations to mine and put together the complete package to do the actual mining.  (Why build habitats when you don't have a location for them picked out yet?)

 

The biggest problems for long term space travel today are not habitats or propulsion but human biology and the steady funding levels needed to put people into space.

 

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deesy58
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Re: Is star travel practical in theory now? Some Food for Thought.


WONK wrote:

<I believe that your analogy breaks down.  If a particular launch system is not able to launch a satellite, would you continue to use it without introducing any corrections or improvements?>

 

That is true only if there is a flaw in the whole system.  Any new product will fail in some way and needs to be fine tuned.  If new products were perfect there would be no recalls.  How many times do car companies have recalls every year?  Do they junk the whole car or give up on driving?  Biosphere II had many small problems.  For example it frequently leaked.  Does not having enough caulking on a seam mean that the whole project doesn't work?  We use the same rockets that failed in the past mutliple times during many military and civilian projects but we seldom scrap the whole rocket.  We find the small part that isn't working and send up the rocket again.

 

< If the earlier experiments failed, and if we know why they failed, and if we have the technology to repeat the experiments in a more successful manner, then why aren't we doing so?>

 

The answer is money.  It takes a lot of money to run an isolated system large enough to support a number of people and there are few sources of funding for that.  You will see the money for this type of research appear when a few commercial mining projects locate minerals that are economically viable.  The R&D funders would be doing more basic research now if most thought that habitats are big bottlenecks for space mining.  Or the time line needed to produce the habitats is much shorter than the time line needed to find the ideal locations to mine and put together the complete package to do the actual mining.  (Why build habitats when you don't have a location for them picked out yet?)

 

The biggest problems for long term space travel today are not habitats or propulsion but human biology and the steady funding levels needed to put people into space.

 


Umm ... it wasn't a small problem that plagued Biosphere 2, it was a number of very large problems.  According to Wikipedia:

 

"Biosphere 2 suffered from CO2 levels that "fluctuated wildly" and most of the vertibrate species and all of the pollinating insects died.  Insect pests, like cockroaches, boomed. In practice, ants, a companion to one of the tree species (Cecropia) in the Rain Forest, had been introduced. By 1993 the tramp ant species Paratrechina longicomis, local to the area had been unintentionally sealed in and had come to dominate. Galagos reproduced in Biosphere 2, but a number of pollinating insects were lost to ant predation and several bird species were lost. However, many of the pollinating duties were performed by those ants and cockroaches."

 

"The oxygen inside the facility, which began at 20.9%, fell at a steady pace and after 16 months was down to 14.5%. This is equivalent to the oxygen availability at an elevation of 4,080 meters (13,400 ft). Since some biospherians were starting to have symptoms like sleep apnea and fatigue, Walford and the medical team decided to boost oxygen with injections in January and August 1993."

 

http://en.wikipedia.org/wiki/Biosphere_II

 

From there, everything continued downhill until the mission was ended.  It is not clear whether the second mission might have been more successful than the first, but leakage was not the primary issue.  Clearly, mankind needs to acquire a great deal more knowledge and technology before space colonization will become feasible.  Money, alone, cannot solve all problems.  Time also plays a role. 

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JimJoe
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Re: Is star travel practical in theory now? Some Food for Thought.

Or launch from lunar orbit. With the ships built on the Moon. Wouldn't need streamlining. Only the Mars  landers it carried would need that.

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WONK
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Re: Is star travel practical in theory now? Some Food for Thought.

Are you familiar with complex systems?  Small things (popularly known as butterfly affects) crash the system.  Possibly the biggest problem with the Biosphere was the accidental introduction of ants.  That alone could have caused most of the problems including the oxygen levels.

 

There would have been multiple ways of continuing the experiment but they would all require running the system longer.  Note: You remove the people and run the system until the biological cycles create a stable environment.  But again this experiment wasn't the same as a space craft biosphere.  In a space craft biosphere there would be mechanical adjuncts and a more limited mix of lifeforms.  For example: On a space craft you wouldn't depend on a natural cycle for pollination.  Biosphere was an experiment for a permant non-earth type settlement.  It actually failed the instant the invasive species were accidently introduced.  A true space travel experiment would use very select species and the system woud be run by introducing species individually and again to limit the invasive species problem you would use mechanical adjuncts as much as possible.  The first step would be creating a stable oxygen cycle which would most likely include a mechanical sewage system with algae and selected other plants grown hydroponically.  Note this is different from Biosphere where a more natural cycle was attempted. 

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deesy58
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Re: Is star travel practical in theory now? Some Food for Thought.


WONK wrote:

Are you familiar with complex systems?  Small things (popularly known as butterfly affects) crash the system.  Possibly the biggest problem with the Biosphere was the accidental introduction of ants.  That alone could have caused most of the problems including the oxygen levels.

 

There would have been multiple ways of continuing the experiment but they would all require running the system longer.  Note: You remove the people and run the system until the biological cycles create a stable environment.  But again this experiment wasn't the same as a space craft biosphere.  In a space craft biosphere there would be mechanical adjuncts and a more limited mix of lifeforms.  For example: On a space craft you wouldn't depend on a natural cycle for pollination.  Biosphere was an experiment for a permant non-earth type settlement.  It actually failed the instant the invasive species were accidently introduced.  A true space travel experiment would use very select species and the system woud be run by introducing species individually and again to limit the invasive species problem you would use mechanical adjuncts as much as possible.  The first step would be creating a stable oxygen cycle which would most likely include a mechanical sewage system with algae and selected other plants grown hydroponically.  Note this is different from Biosphere where a more natural cycle was attempted. 


Well, here's something to chew on.  We put a man on the moon in 1969.  That was how many years ago?   ... Oh yeah, 43.  And what spectacular feats have we accomplished in space since that time (not counting robots)?

 

And so, between 1969-1972 we put several men on the moon and set our sights on Mars.  President George W. Bush promised a manned mission to Mars in a State of the Union speech.  Newt Gingrich promised a human colony on Mars if he won the presidency.  How much progress have we made in forty years?  Why should we believe that all of the scientific and political problems will be solved in the near future if they haven't been solved in forty years? 

 

We might get there eventually, but it will take a lot longer than the science fiction writers would have us believe.  It's okay to dream as long as we don't confuse our dreams with reality. 

 

Oh, and the ants breathed up all the oxygen in Biosphere 2?!  They also killed all the birds and other vertebrates.  Nasty creatures.  If you believe that, could I show you a beautiful antique bridge in New York that can be had for a very low price?   

 

Remove the people?  Aren't people a part of the ecosystem?  What would be accomplished by proving that life could exist without the presence of humans?  We already know that.  It has existed for millions, if not billions of years before Man came along.

 

Why would anybody conduct an experiment to create a completely closed biological environment, including humans, if not to see if it was possible to live in space for very long periods of time without outside sustenance and assistance?  I mean ... where else might such an environment be useful (except under the sea)?  What sort of mechanical devices might be able to produce sufficient amounts of food, water and oxygen to last for many, many years?  I'm referring to real devices, not fictional devices. 

 

Nope.  I'm not convinced that this particular science isn't still a ways off.  I don't expect that either of us will see it in our lifetimes. 

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WONK
Posts: 45
Registered: ‎09-06-2012

Re: Is star travel practical in theory now? Some Food for Thought.

First the problems over the last 40 years have been with funding.  Politicians kept changing the funding to different projects.  Without a fundling line that actually lasts past a single politician's tenure space exploration is a mixed project.  To do the large projects such as space colonies and travel, you need a solid funding line that doesn't vary significantly for a period between 10 to 15 years and that funding line has to ignor short term special projects that drain the long term project.  After the Moon landings funding was cut, shifted, cut, shifted to political projects, cut, shifted... every 2 to 4 years depending on which politicians were elected.  For example the space shuttle was built not because it was the best or cheapest way into space but for political reasons and the huge costs to run the shuttle cut funding to the space station and travel outside of earth's orbit.

 

From your comments it is obvious you don't understand complex systems.  There are many fine books on the topic.  I like those by my friends Jack Cohen and Ian Stewart.  Stewart is a mathematician who regularly writes for Scientific America and Cohen is a biologist who you might have seen on the Discovery Channel.  Invasive species (such as ants) can collapse a biological feedback system.  An example (note this isn't what happened but what might have happened):  Ants kill the instects needed by the oxygen producing plants to thrive.  This reduces the amount of carbon converted to oxygen in the habitat.  This then reduces the health of the insects and animals needed by the plants.  This feedback then increases the carbon even more...  The feedback loops between species in biological systems set the cycles that occur in the system.  Or, depending on the mix and health of the biomass and chemical mix, the results are different levels of the materials in the cycles such as the oxygen and carbon.  An example here is that we are now going into a high carbon period on the earth and there will be a different mix of the biomass on earth because of the cycle.

 

I suggested that it is not advisable to put human experimentors in a dangerous situation so you could replace there carbon/oxygen footprint in the biocycles with animals while an unstable biosphere works its way into balance.  The Biosphere had a shifting oxygen/carbon atmosphere.  If you run a closed system long enough those plants and animals in the system will eventually find a balance between their needs and the Biosphere carbon/oxygen cycles will become stable.  During the instability many plants and animals in the Biosphere will die.  It is therefore preferable that you use animal replacements for the oxygen/carbon foot print of humans in the experiment if you want to run the experiment until it becomes stable.

 

You also seem to have a problem with mechanical adjuncts.  A simple mechanical adjunct is hydroponics.  Another would be a mechanical system to speed the conversion of waste by bacteria and algae using temperature, energy introduction (grow lights) and mechanical mixing in the algae tanks.  Mechanical adjuncts speed up and reduce the physical size needed for a balance biosystem.  In these examples the mechanical additions to the waste coversion cycle would increase and speed up the waste coversion by the bacteria and algae in the waste cycle and the hydroponics would reduce the area and nutrients needed for vegetation.  You could also replace pollination by insects (an unneeded extra addition to the biological cycles) by artificial pollination.  You would do this because by adding insects into the system you would need to increase the size of the biosphere and put in a biological check to the insects so they don't over populate the system.  (Too many insects can harm others the the biomass by increasing or decreasing substances needed by the other lifeforms in the system.)

 

Most people tend to look at things in a linear way where only one thing is the key for something to work.  Complex systems is a method of looking at real life where a series of small butterfly affects cause chain reactions that result in large changes.  Complex systems don't just explain how small things are needed for larger systems to work but gives information on controlling the larger systems.

 

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deesy58
Posts: 2,486
Registered: ‎01-22-2012

Re: Is star travel practical in theory now? Some Food for Thought.

[ Edited ]

First the problems over the last 40 years have been with funding.  Politicians kept changing the funding to different projects.  Without a fundling line that actually lasts past a single politician's tenure space exploration is a mixed project.  To do the large projects such as space colonies and travel, you need a solid funding line that doesn't vary significantly for a period between 10 to 15 years and that funding line has to ignor short term special projects that drain the long term project.  After the Moon landings funding was cut, shifted, cut, shifted to political projects, cut, shifted... every 2 to 4 years depending on which politicians were elected.  For example the space shuttle was built not because it was the best or cheapest way into space but for political reasons and the huge costs to run the shuttle cut funding to the space station and travel outside of earth's orbit.

 

To say that we have seen delays in NASA’s space programs because of politics, therefore if politics were eliminated NASA would be able to sustain human life in space for extended periods using existing technology is false logic.  It does not follow that all of the technology necessary to sustain human life on a Mars or Moon colony, or on a “generation” starship, is available today.  We have absolutely no proof that such a feat could be accomplished using currently available technology.  It is a matter of “faith” to believe otherwise. 

 

From your comments it is obvious you don't understand complex systems.  There are many fine books on the topic.  I like those by my friends Jack Cohen and Ian Stewart.  Stewart is a mathematician who regularly writes for Scientific America and Cohen is a biologist who you might have seen on the Discovery Channel.  Invasive species (such as ants) can collapse a biological feedback system.  An example (note this isn't what happened but what might have happened):  Ants kill the instects needed by the oxygen producing plants to thrive.  This reduces the amount of carbon converted to oxygen in the habitat.  This then reduces the health of the insects and animals needed by the plants.  This feedback then increases the carbon even more...  The feedback loops between species in biological systems set the cycles that occur in the system.  Or, depending on the mix and health of the biomass and chemical mix, the results are different levels of the materials in the cycles such as the oxygen and carbon.  An example here is that we are now going into a high carbon period on the earth and there will be a different mix of the biomass on earth because of the cycle.

 

Your comments regarding complex systems appear not to be relevant to the central gist of our differences in opinion.  Read the information about the oxygen problem at Biosphere 2.  None of the scientists (that I noticed, anyway) posited that the ants had anything to do with the oxygen levels.  In fact, they stated that the ants and cockroaches began to perform the pollination duties usually completed by other species.  They did, however, discover that the concrete under-flooring in the complex was causing the CO2 in the interior atmosphere to become bound in the formation of Calcium Carbonate, resulting in a lower than expected level of CO2, but I did not see any conclusions about the dramatically lower levels of O2 that required supplemental oxygen to be injected into the domes. 

 

In a complex system, what, exactly, is it that a plant might need (other than nutrients, water and light) to continue removing CO2 from the air and producing O2?  Isn’t pollination, the function of some insects and birds, primarily a reproductive function?  Couldn’t the project have used perennial plants that could survive for long periods without the need for reproduction?  You seem to be speculating about the causes of the failure of the first Biosphere 2 mission.

 

I suggested that it is not advisable to put human experimentors in a dangerous situation so you could replace there carbon/oxygen footprint in the biocycles with animals while an unstable biosphere works its way into balance.  The Biosphere had a shifting oxygen/carbon atmosphere.  If you run a closed system long enough those plants and animals in the system will eventually find a balance between their needs and the Biosphere carbon/oxygen cycles will become stable.  During the instability many plants and animals in the Biosphere will die.  It is therefore preferable that you use animal replacements for the oxygen/carbon foot print of humans in the experiment if you want to run the experiment until it becomes stable.

 

So how is it helpful to establish a stable ecosystem in which humans are not able to survive?  Humans are animals that are a part of the ecosystem.  It would seem to be unhelpful to establish a closed ecosystem in which humans are not present just to see what results (unless the purpose is simply to obtain a government grant and satisfy some curiosity).   What animal would you suggest might be a perfect replacement for humans in such an experiment? 

 

You also seem to have a problem with mechanical adjuncts.  A simple mechanical adjunct is hydroponics.  Another would be a mechanical system to speed the conversion of waste by bacteria and algae using temperature, energy introduction (grow lights) and mechanical mixing in the algae tanks.  Mechanical adjuncts speed up and reduce the physical size needed for a balance biosystem.  In these examples the mechanical additions to the waste coversion cycle would increase and speed up the waste coversion by the bacteria and algae in the waste cycle and the hydroponics would reduce the area and nutrients needed for vegetation.  You could also replace pollination by insects (an unneeded extra addition to the biological cycles) by artificial pollination.  You would do this because by adding insects into the system you would need to increase the size of the biosphere and put in a biological check to the insects so they don't over populate the system.  (Too many insects can harm others the the biomass by increasing or decreasing substances needed by the other lifeforms in the system.)

 

Hmm.  You are beginning to launch ad hominem attacks.  Perhaps I understand more than you think, and perhaps I am trying to avoid the confusion between belief and fact.  What makes you so sure that an invasive species could not be accidently introduced into any closed ecosystem?  Look, for example, at the amounts of money currently being spent in the United States (including Guam) to combat their impact. 

 

Most people tend to look at things in a linear way where only one thing is the key for something to work.  Complex systems is a method of looking at real life where a series of small butterfly affects cause chain reactions that result in large changes.  Complex systems don't just explain how small things are needed for larger systems to work but gives information on controlling the larger systems.

 

What is your point?  Do you have one, or are you simply trying to cast aspersions?  How does the subject of complex systems have anything whatsoever to do with whether or not current technologies are sufficiently advanced to allow humans to survive for extended periods in space without external assistance?  You believe they are.  I believe they are not.

 

Up to now, there has been no credible proof that humans can survive for extended periods in a completely closed system.  It would be an especially virulent form of insanity to attempt to establish colonies on the Moon or Mars, or to build a “generation ship” with nothing more than faith to support such missions.  Color me skeptical!

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Omnigeek
Posts: 901
Registered: ‎01-25-2011
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Re: Is star travel practical in theory now? Some Food for Thought.

Hmmm ... a lot of discussion while I've been away.

 

1.  Let's make a distinction between political will or financial priorities that interfere with extraterrestrial colonization, engineering problems that need to be solved and physics problems that make things unrealistic.  There's a lot more we could have done in the past 40 years had we had the political will and placed a priority on it.  Biosphere II was an example of engineering problems that need to be fixed -- and can be.  Trying to get FTL drive is a physics problem.

 

2.  My first objection to deesy58's dogmatic statements was in both the engineering and physics realms.  S/he stated categorically that anyone riding on an ORION-type platform would be "squashed like a bug" -- patently false.  Getting squashed is a result of the acceleration or jerk (rate of change of acceleration) and those would be functions of the force of the explosion(s), rate of fire and mass being propelled.  Really a relatively simple engineering problem.

 

3.  I raised Biosphere II as an example of engineering problems that need to be solved to make generational ships a reality.  It's not hard, just a function of engineering the relative sizing of components and systems; this is made easier by going ahead and DOING hard experimentation and getting the data.

 

4.  FTL drive is -- as far as we know now -- just not something we can do.  Period.  That's doesn't mean we can't reach relativistic speeds that would make single-generation interstellar travel possible but we'd have to commit to resources over a long span of time in order to make it happen.  That's why I raised Robert Forward's novels -- he lays out all the physics necessary to make a trip to Proxima Centauri and even farther BUT someone would have to lay out the resources to build a light sail ship and power it with a terawatt-class laser (probably solar-powered) for decades.  Oh yeah, and robotically construct and operate an analog at the distant end or it'll be a one-way trip.  Practical in physics and even engineering but probably not practical in terms of human dynamics.

 

5.  We DO have all the engineering we need to sustain human life for extended periods of time outside the Terran biosphere.  We have had that for quite some time and engineering advances mean we could do it even better now -- what we DON'T have is the will and resource commitment to do so.  Of course we have proof that we can do it -- we sent men to the moon 43 years ago.  They lived outside the Earth's gravity well for over a week; longer periods are just a matter of scale.  We've had space stations in orbit continuously inhabited (albeit by different people and with periodic resupply) for years now.  NASA could probably have slowed the resupply if funding had been available to design and build modules to capture and refine water, photosynthesize oxygen (more likely using algaes than pollinating plants), etc.  Again, a problem of will and resource commitment -- NOT of physics or engineering.  We routinely send submarines underwater for months at a time so it's not like we don't have the engineering necessary to sustain life for extended periods.

 

6.  On the other hand, we had best plan on and engineer for additional critters to hitch a ride with us because it happens.  There WILL be deficiencies in any system designed so we have to plan and test them with adequate margins.

 

7.  Simply observing that someone has a problem with mechanical adjuncts isn't an ad hominem attack so let's not get overwrought about that.  The fact of the matter is that there ARE mechanical ways get around some biological processes.

 

8.  Fine, you're skeptical.  I'm not sure what color that is but I'll find a pigment for it -- maybe mud brown?  There's plenty of engineering and physical evidence that extraterrestrial colonization CAN be done with the right will and resource commitment although the jury is out on periods as long as generational ships or interstellar travel would require.  Far more evidence for a Moon or Mars base than existed for supersonic travel 80 years ago or intercontinental transoceanic travel 600 years ago.

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deesy58
Posts: 2,486
Registered: ‎01-22-2012
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Re: Is star travel practical in theory now? Some Food for Thought.

[ Edited ]

omnigeek said:

 

Hmmm ... a lot of discussion while I've been away.

 

1.  Let's make a distinction between political will or financial priorities that interfere with extraterrestrial colonization, engineering problems that need to be solved and physics problems that make things unrealistic.  There's a lot more we could have done in the past 40 years had we had the political will and placed a priority on it.  Biosphere II was an example of engineering problems that need to be fixed -- and can be.  Trying to get FTL drive is a physics problem.

 

You are speculating!  Your assertions are nothing more than conjecture!  We have absolutely no way of knowing what might have happened “if only” political will and funding levels had been different.  “Coulda, shoulda, woulda.”  Meaningless! 

 

2.  My first objection to deesy58's dogmatic statements was in both the engineering and physics realms.  S/he stated categorically that anyone riding on an ORION-type platform would be "squashed like a bug" -- patently false.  Getting squashed is a result of the acceleration or jerk (rate of change of acceleration) and those would be functions of the force of the explosion(s), rate of fire and mass being propelled.  Really a relatively simple engineering problem.

 

I did a search on the phrase “squashed like a bug” and found only one place where it was used.  You (omnigeek) said it a week ago.  http://bookclubs.barnesandnoble.com/t5/Fantasy-Science-Fiction/Is-star-travel-practical-in-theory-no...

 

It appears that I did not make such an assertion, but that you did.  Then, you accuse me of saying it, even including the phrase in quotation marks in order to make your assertion more convincing.  You seem to have a dispute with ManuelGarcia, a person who clearly has a greater knowledge of Physics than I do.  Why don’t you address your arguments to ManuelGarcia?  In the meantime, I remain unconvinced that the technology exists NOW that would allow humans to survive for long periods in space. 

 

3.  I raised Biosphere II as an example of engineering problems that need to be solved to make generational ships a reality.  It's not hard, just a function of engineering the relative sizing of components and systems; this is made easier by going ahead and DOING hard experimentation and getting the data.

 

Well, we apparently did do a hard experiment less than twenty years ago, and it was a failure.  Biosphere 2 appears now to be, primarily, a tourist attraction. 

 

4.  FTL drive is -- as far as we know now -- just not something we can do.  Period.  That's doesn't mean we can't reach relativistic speeds that would make single-generation interstellar travel possible but we'd have to commit to resources over a long span of time in order to make it happen.  That's why I raised Robert Forward's novels -- he lays out all the physics necessary to make a trip to Proxima Centauri and even farther BUT someone would have to lay out the resources to build a light sail ship and power it with a terawatt-class laser (probably solar-powered) for decades.  Oh yeah, and robotically construct and operate an analog at the distant end or it'll be a one-way trip.  Practical in physics and even engineering but probably not practical in terms of human dynamics.

 

I don’t believe that citing a Science Fiction novel is a particularly convincing technique of persuasion.  Has Mr. Forward published his theories in any peer-reviewed journals?  Is he an acknowledged astrophysicist? 

 

5.  We DO have all the engineering we need to sustain human life for extended periods of time outside the Terran biosphere.  We have had that for quite some time and engineering advances mean we could do it even better now -- what we DON'T have is the will and resource commitment to do so.  Of course we have proof that we can do it -- we sent men to the moon 43 years ago.  They lived outside the Earth's gravity well for over a week; longer periods are just a matter of scale.  We've had space stations in orbit continuously inhabited (albeit by different people and with periodic resupply) for years now.  NASA could probably have slowed the resupply if funding had been available to design and build modules to capture and refine water, photosynthesize oxygen (more likely using algaes than pollinating plants), etc.  Again, a problem of will and resource commitment -- NOT of physics or engineering.  We routinely send submarines underwater for months at a time so it's not like we don't have the engineering necessary to sustain life for extended periods.

 

If we really did have “… all the engineering we need to sustain human life for extended periods of time outside the Terran biosphere …” why must we regularly send resupply missions to the International Space Station (ISS)?  If we could have simply made the ISS self-sufficient using currently available technologies, wouldn’t that have been much less expensive and risky than using (formerly) the Space Shuttle, and (now) automated Russian resupply vehicles to deliver food and oxygen? 

 

6.  On the other hand, we had best plan on and engineer for additional critters to hitch a ride with us because it happens.  There WILL be deficiencies in any system designed so we have to plan and test them with adequate margins.

 

Well, at least one other contributor seems to disagree with you.  Perhaps you don’t understand complex systems?  :smileywink:

 

7.  Simply observing that someone has a problem with mechanical adjuncts isn't an ad hominem attack so let's not get overwrought about that.  The fact of the matter is that there ARE mechanical ways get around some biological processes.

 

Duh!  We have known for a very long time that mechanical systems can supplement or replace some biological systems.  Stretching that knowledge into a belief that, therefore, we can replace ALL biological systems with mechanical adjuncts is naïve. 

 

8.  Fine, you're skeptical.  I'm not sure what color that is but I'll find a pigment for it -- maybe mud brown?  There's plenty of engineering and physical evidence that extraterrestrial colonization CAN be done with the right will and resource commitment although the jury is out on periods as long as generational ships or interstellar travel would require.  Far more evidence for a Moon or Mars base than existed for supersonic travel 80 years ago or intercontinental transoceanic travel 600 years ago.

 

Well, here again, we are recipients of your opinions.  What (specifically) is your source for the contention that the technology required to establish and sustain a human-populated colony on the Moon or Mars currently exists?  Your own observations about 80 years and 600 years seem to support my position that space colonies are still in the distant future (not in our lifetimes, no matter how young you might be).