Human space travel - prospects?

[sphenisc]

The moon shots took nearly fifteen years of dedicated and well-funded research (after the creation of NASA) and a humungously large chunk on the NDP. And that is only three days at moderate speeds both ways.

This isn't even the problem just of human physical limitations and requirements for long-distance space travel, it is about limitations imposed by the laws of physics on top of that.

Victor J. Stenger, Professor of Physics and Astronomy and a Fellow of CSICOP, makes the unassailability of these problems rather clear in his "Marooned on Spaceship Earth" article (no link, but certain that is either linked from his site or easily found at CSICOP's). And I agreed with these prior to reading it.

The first and most pressing problem for any space travel beyond the Moon is artificial gravity. Study after study and finding after finding of long-term effects of microgravity show this: 'no gravity, no long-term space travel'. It decreases bone and muscle mass (including the heart) and impacts physiological functions all in adverse ways. So far, we only know three ways to create gravitational acceleration:

Humans spend nine months of their existence in a state of almost neutral buoyancy.This is also the state where there is a minimum of demands in terms of feeding, oxygen and stimulation, and waste-recycling is built in. Of course this raises alternative problems related to providing an automated rearing system on arrival to develop a 'useful' astronaut some 12 or so years later.

 

[Ceritus]

Well this is an uneducated question but....
If we were able to come to a breakthrough in consciousness and be able to record all stored knowledge within the brain and be able to input this 'knowledge' into brains as well. Wouldn't it be possible to upload a certain consciousness into a robot or numerous robots "mechanical beings" and send them on their merry way into all directions of space without having to worry about common human frailties?

If we were to develop a way to protect simple celled organism's from flash freezing and being thawed out from temps of absolute zero wouldn't it then be possible to send these conscious robots equipped with the basic materials needed to form a human being like egg sperm and when needed a hospitable environment for them to grow when said robot reaches it's destination? Whether it is by harvesting energy for these developing human being through a sort of photosynthesis or possibly something better?

That or be able to create a closed environment that perfectly recycles the needs of various generations on their many generations long trip to the nearest galaxy?

I just don't understand why we would have to travel at the speed of light at all. Heck if we were able to flash freeze human beings with no damage when flawing we could send them on billion light year trips given our machinery doesn't breakdown within this billion light year trip.

As for keeping gravity around couldn't we have the transport or whatever spin continuously?

 

[kuroyume0161]

The first thing we have to do is find out how much acceleration is required to maintain health. This is a good reason to go back to the Moon. It might turn out that 2m/s^2 plus resistance training is enough to maintain reasonable health.

And, as far as I know, there have been no such studies done or proposed yet to determine a suitable minimal gravitational acceleration (with some counterbalancing human effort as you mention). Seems all of the attention is on how to spend 23.99 hours a day (sarcasm there) doing nothing but exercise to maintain health for microgravity environments.

No argument with you about this. My argument is that if we are to consider seriously any long-term space travel (the most likely to occur first would be to Mars), we must give up any notion of surviving in a microgravity environment. It is not possible. The current joke is that if the astronauts survive the microgravity and radiation (and whatever else) on a Mars voyage, their bodies will disintegrate upon landing because of the extensive degradation of bone and musculature. A one way trip to their grave on Mars.

So, why are we expending all of our time, money, research, and intelligence on Rube Goldberg machines that do nothing more than provide a less than minimal force to only partially stave off the effects when we should be actively working on ways to create artificial gravity? We are doing such studies for replenishable air, water, and food supplies (as they will be absolutely needed - can't take it all with you). Why the goofal here?

Artificial gravity solves a long list of problems:

1. Bone and musculature decay.
2. Blood flow.
3. Correct resistance to other internal forces.
4. Inner-ear nausea and disorientation.
5. General disorientation due to lack of 'up' reference.
6. Running water (showers, toilets, etc).
7. Sleeping, eating, and expelling.
8. Long hours of almost useless routines.

In other words, all of the comforts for which we are evolved and accustomed. The only two disadvantages of artificial gravity are:

1. No more free floating about.
2. Massive objects now have weight.

The best solution I've seen for this is to have the crew compartment on a long tether connected to the engines, so the engine unit would pull the crew compartment providing linear acceleration. When the system is coasting, the engine unit and crew compartment would be set spinning. There are no insurmountable problems with this. The chief problem would be to keep the reaction mass from frying the cable or the crew compartment, but that could be handled by having the engines point at a slight angle. It might even be an advantage, as if the engines were hot (in the sense of radioactive), it would be nice to keep them far away. Going from dragging mode to revolving mode has non-obvious details, but we have good computers.

This is the best proposal that I've seen (thanks for reminding me of it!). Again, these need to be lifted from the 'drawing board' and put into testing mode. Start with something small (using ants, rats, fleas, sensored robots, I don't care). But dreaming about this stuff and finding real solutions won't happen while were dreaming.

 

[kuroyume0161]

Well this is an uneducated question but....
If we were able to come to a breakthrough in consciousness and be able to record all stored knowledge within the brain and be able to input this 'knowledge' into brains as well. Wouldn't it be possible to upload a certain consciousness into a robot or numerous robots "mechanical beings" and send them on their merry way into all directions of space without having to worry about common human frailties?

If we were to develop a way to protect simple celled organism's from flash freezing and being thawed out from temps of absolute zero wouldn't it then be possible to send these conscious robots equipped with the basic materials needed to form a human being like egg sperm and when needed a hospitable environment for them to grow when said robot reaches it's destination? Whether it is by harvesting energy for these developing human being through a sort of photosynthesis or possibly something better?

That or be able to create a closed environment that perfectly recycles the needs of various generations on their many generations long trip to the nearest galaxy?

I just don't understand why we would have to travel at the speed of light at all. Heck if we were able to flash freeze human beings with no damage when flawing we could send them on billion light year trips given our machinery doesn't breakdown within this billion light year trip.

As for keeping gravity around couldn't we have the transport or whatever spin continuously?

Wow, you are talking many ifs there!

A big conundrum here is why send fleets of spacecraft out to never return? For exploration purposes, there is no benefit since none of the exploration results will reach Earth for many years (centuries, millenia, eons) - there might not even be anybody listening for them by the time they arrive. For colonization purposes? Without feedback on successes, we are just 'shooting our sperm' in random directions hoping to impregnate a woman in another country (to put it crudely). It would make no difference to any plight on Earth while possibly dooming the colonists to some horrid end.

Cryo-statis would require AI to maintain systems for such long journeys (HAL comes to mind). But it would require active systems of repair. Radiation, micrometeors, gas and dust, and a slew of possible normal failure issues would require that while the human crew is in statis, something is monitoring and maintaining the spacecraft. And you can't take a spare (or fifty-million) with you. So the AI system would need to be able to manufacture spare replacement parts from somewhere (say, by diverting to a solar system and acquiring the necessary materials). That requires a means of 'mining' and manufacturing (manufacturing at all capacities). Therefore, you need to bring an entire mining and manufacturing complex with you (that needs to be maintained). Having to consider travels of thousands, millions, billions (!) of years changes everything. You must now carry an entire self-sustaining system with you that can forage for needed supplies en route.

 

[Ceritus]

Ok fair enough.... let me toss out one more if situation.

If we were able to build organisms or objects at the atomic level and have enough energy to do it of course. Couldn't we for example create an analyzer and a builder where the analyzer would scan an object at the molecular level and then send the information to the builder which would breakdown various elements in it's current environment like dirt dust rocks ect and then rebuild a duplicate of the object scanned by arranging the protons electrons neutrons and nuclei from however much environmental substance was needed to get the correct amount and then fuse them together in the exact same fashion of the object being analyzed. Since radio waves travel at the speed of light then the light travel problem would be solved after the builder has arrived would it not?

I know I have a wild imagination.

Also before we send out the cryo-car ofcourse we would have to have well planned restroom breaks!

 

[sphenisc]

Ok fair enough.... let me toss out one more if situation.

If we were able to build organisms at the atomic level and have enough energy to do it of course. Couldn't we for example create an analyzer and a builder where the analyzer would scan an object at the molecular level and then send the information to the builder which would breakdown various elements in it's current environment like dirt dust rocks ect and then rebuild a duplicate of the object scanned by arranging the protons electrons neutrons and nuclei from however much environmental substance was needed to get the correct amount and then fuse them together in the exact same fashion of the object being analyzed. Since radio waves travel at the speed of light then the light travel problem would be solved after the builder has arrived would it not?

I know I have a wild imagination.

Wild... but not that wild...

http://fab.cba.mit.edu/

 

[elgarak]

I see now that kuroyume0161 and I have fundamentally different perspectives. Like optimists and pessimists, glass half empty, half full.

He sees dangers, where I see challenges. He fears space travel might be useless, where I think that it might be useful, though we probably will not find what we are looking for.

True, there are many ifs. It takes 1e6 steps to do interstellar space travel (in 1e6! different ways). We have done the first 100. Now its time to do the 101st.

 

[kuroyume0161]

I'm nowhere near a pessimist. I'm a realist. Have you looked at your primate buddies recently? We couldn't combine our brain-power to stop a single war and you want to traverse the known universe. We are animals evolved for a specific environment (Earth after 5 billion years) and we will probably not survive as a species for more than another 10 million years if we're lucky. What will happen - extinction, evolution, who knows. But we are not bred for the harshness beyond even the lower atmosphere (or the depths of our seas). This will require either amazing technologies (far, far into the future) or adaptation (i.e.: evolution - whether natural or artificial).

It takes more like 10e10 steps to do instellar travel and we've done the first 10e1. There are far more than a million steps involved. I'll have to compile my full list of problems to overcome. Then you will see that the glass is almost broken...

 

[DrKyle]

To the stars.

Being one trained in physics, and thus know the limitations, and thus, plausibility, set upon humanity with respect to our traversing great distances, I am aware that all the sum of our knowledge has yet to definitively unlock any possibilities for such a fantastic dream as interstellar travel.

However, either statement of : A) It is not possible, so I will not think on it; or B) I know it will be possible, so I will endlessly speculate on how, are, by their own merit, seriously flawed.

A scientist who lives by his code of "the method", utilising it as an actual philosophy for his existence is as flawed and meandering as those dreamers daring their imagination onward without use of this scientific method, without keeping a firm footing in the world of the real. One must have a healthy dose of either to be that most blessed of men: the innovator, the thinker, the curious creature that, for all its knowledge enclosing them like a comfroting bubble, they are forever pushing on it.

Einstein saw a beam of light, with time hopelessly trying to keep up with it, and failing. Newton dreamed of planets holding planets holding further planets in their orbits held firmly in place by a brilliant yellow star. All these fires of reason were reared by what? Science? Logic? No. Those things are what upon which these thoughts were fueled. Those fires were formed by sparks, and those sparks from where? From the man of course. The man who, despite the prevailing mystery, the difficulty, the seemingly impossibility of a chaos uncounted, reached up into the sky and said "How? Why?" and thus went from there.

We may think of these men as artists, and scientific thought, or method, as the brush and the paint and the canvas. These men and women with a dream of how the world is wielded, represented by the mathematics, the logic, the experiments that guide us further on to illumination, or prove us wrong, which inevitably points us right (think edison).

It may be wise to be solely logical, and it may be comforting to rely on nothing but an emotion that enables curiousity and creativity, but only those with both are those with wisdom.

I never say it won't ever be so, I say, perhaps. I never say it will be so, I say perhaps. But whatever I say, I'll always look. That's why I became a scientist.

 

[Soapy Sam]

Eggs.
Basket.
Asteroid.
Time.
Overpopulation.
Ice Age.
Supervolcano.
Moon.
Mars.

Do. Or do not. There is no "try". -Yoda.

We get off our collective arse, or we die here.
Those are the alternatives.

Interstellar travelmay be difficult. Interstellar colonisation may be fantasy.
That does not mean we should balk at the first step.

 

[kuroyume0161]

Yes, exactly, Soapy Sam! Do or do not. There is no try.

We haven't done and we haven't tried. President Bush's 'promises' to go back to the Moon and then on to Mars are political rhetoric. We haven't any means at this time (and we're quickly squandering our resources, oh, on a fake war and continuous natural disasters - some of which were avoidable).

Personally (and that means IMHO), I don't think humanity can get off its collective arse and actually do it. Maybe a little evolution away from our ancestors will curtail the territorial urges and wanton stupidity, one can only hope. That would push the possibilities into the future at least 10,000 years (since we haven't done much evolving in the past 10,000).

We are already stumbling. And it will take a much steadier and sturdier gate to reach the stars!

 

[epepke]

So, why are we expending all of our time, money, research, and intelligence on Rube Goldberg machines that do nothing more than provide a less than minimal force to only partially stave off the effects when we should be actively working on ways to create artificial gravity? We are doing such studies for replenishable air, water, and food supplies (as they will be absolutely needed - can't take it all with you). Why the goofal here?

Well, you're talking politics here. That's difficult.

As far as I can tell, the majority consists of three sorts of people:

1) People who think that we shouldn't be doing space travel at all (why spend lots of money out in space when we could spend it right here on Earth?) These people somehow think that we are putting dollar bills into orbit.

2) People who think that we shouldn't have any human space flight because robotic probes are much more efficient for doing science. These people seem to think that the only possible purpose of a frontier is to do science, and also are operating under an economy of poverty.

3) People who think that it would be OK to send humans into space when we're ready, but they don't seem to have any idea of how we're going to get ready.

This is the best proposal that I've seen (thanks for reminding me of it!). Again, these need to be lifted from the 'drawing board' and put into testing mode. Start with something small (using ants, rats, fleas, sensored robots, I don't care). But dreaming about this stuff and finding real solutions won't happen while were dreaming.

Rats would be a good start. Ants and fleas have exoskeletons and don't have hearts, so I don't think that would be much use. One could put up a revolving-box-o-rats for not much more than a typical communications satellite. Retrieving them would probably take a shuttle mission, though.

 

[CurtC]

2) People who think that we shouldn't have any human space flight because robotic probes are much more efficient for doing science. These people seem to think that the only possible purpose of a frontier is to do science, and also are operating under an economy of poverty.

I guess you're trying to describe me in group number 2, but you fell short. There is not purpose for space exploration right now except for science. Maybe someday, far far in the future, we may want to send humans out there for the purpose of living there. But there is no possible way we could even begin to have a hint of coming close to this questionable goal right now anyway. Why not work on the fundamental technologies of space propulsion through the robotic program, while experimenting on sustainability of humans here on the ground where it's cheap and easy?

 

[epepke]

I guess you're trying to describe me in group number 2, but you fell short.

Actually, I wasn't even thinking about you in particular.

There is not purpose for space exploration right now except for science. Maybe someday, far far in the future, we may want to send humans out there for the purpose of living there. But there is no possible way we could even begin to have a hint of coming close to this questionable goal right now anyway. Why not work on the fundamental technologies of space propulsion through the robotic program, while experimenting on sustainability of humans here on the ground where it's cheap and easy?

Well, to my way of thinking, it works like this. We have about 50% of a two-hundred year window left. We've used up half of it. After about a hundred years from now, it won't be practical to fill boosters with kerosene any more, which is what we did with the Saturn V.

I think we should use that time period while stuff like kerosene is still cheap. The Box-O'-Rats would be a nice start. I don't think that this far, far in the future will actually happen unless we start working on it now.

We should also make a moon base. We have the technology to do that now. We should do it. We should find out if humans can live on the Moon, baking oxygen out of rocks.

I don't see much value in putzing about with our thumbs up our butts taking it on faith that the far, far future will just automagically happen. We have to do it. We have to make it happen. If it's expensive, well maybe, but it's a hell of a lot less expensive than it's going to be in 100 years.

 

[kedo1981]

We should forget about Interstellar travel at least for a thousand years.
There is more than enough space (in near space) for us to take up our efforts for several hundred years; the moon, the Lagrange points, Near Earth Rocks.
Crawl before you walk.
When it’s economical feasible to put lots of peeps in space, it will happen, period.

The expansion into space will make the European colonization of the new world look a trip to Grandmas for Christmas (you know, Jesus’s B- day). Billions will die, but that ain’t gone a stop it. Economies will collapse, but that aint gone a stop it .

 

[kuroyume0161]

My main worry is that humans run the risk of never returning to space in any meaningful way. Despite the rhetoric above about JFK, the 'Moon race' was just that. It wasn't about science and discovery, it was about who had the biggest, er, rocket. The entire affair, from Sputnik to Neil Armstrong's first footstep on the Moon, was a competition. Good competition, but competition nonetheless (it is almost analogous to saying that the scientists near the end of WWII were 'doing science' in inventing rockets, jet planes, atomic bombs, and other new war technologies). And we haven't been past LEO since 1972 (33 years ago on December 12th). The US won, so popular attention shifted.

A long term human exploration and colonization of the solar system cannot be achieved on these grounds. It must be on the grounds of increasing resources, knowledge, and 'habitats' for human survivability. And it cannot be postponed for too long. We risk the dwindling of resources caused by an exponentially increasing and expanding population trying to all move into the twentieth century, many others into the twenty-first. The problem is that the shift in scientific endeavors will be forced towards solving these pressing problems and the other will not be just hard, but forgotten. It may take another intervening 'Dark Age' and 'neo-Renaissance' for people to once again be in the state of rediscovery and pushing the idea forward (a thousand years, give or take), maybe after a significant drop in population (growth).

If anyone is to champion the notion that we can actually overcome the long list of issues - gravity, radiation, micrometeors, durations of flight, air/water/food, fuel, and so on, then we need to do the work and not just dream about it. Robert Zubrin has been making proposals for an economically feasible Mars human mission set (that is far less than all of the previous NASA proposals) since before 1996. But in these many years since he started, noone has actually taken up the idea and put it into motion. NASA has listened and, in some minor cases, conceded on the practicality. But he still struggles to even support his basic research here on Earth. We will never go back to the Moon, let alone to Mars, under these circumstances.

 

[DanishDynamite]

The 'Stupid Teleportation topic' thread in the 'Religion and Philosophy' forum reminded me of a particular conundrum that we, as a highly technological society, face.

In the not too distant past, I was very 'starry' eyed about the prospects of humanity venturing out into the universe (to explore strange new worlds, to boldly go...blah, blah). Within the past few years, after careful consideration of the limitations imposed by Einsteinian physics, the physical harshnesses, and difficulties of maintainable resources, I have come to the realization that we are basically stuck here, on Earth, with little chance of going anywhere beyond our rather desolate solar system.

I've mentioned elsewhere that the distance to the nearest star is approximately 24 light years (travelling at light speed, of course). The distances between galaxies is on the order of millions of light years. Worm holes as means to circumvent these vast distances are truly wishful thinking. We have no way to know that two black holes have a connectivity. We have no way to form such a connectivity. We have no way to know how to traverse something where the laws of physics are either pushed to their limits or breakdown completely. EM transmission (teleportation) isn't even tenable. It not only suffers from cohesion and correction issues, but the same ones imposed by Einstein. Even at Einsteinian speeds (light speed), we are inept at traversing even a miniscule portion of our own galaxy in the next million years!

Barring spectacular scientific discoveries within the next century that circumvent these limitations, what are your thoughts on the prospect of humans actually doing viable space travel?

The prospects are very good, assuming of course that we don't erradicate ourselves before we launch.

Given that assumption, there are a multitude of ways we could explore the galaxy. Some of these have already been mentioned (slow Arks, von Neumann machines, etc).

We have the technology today to make some of these prospects happen. We don't currently have the overriding urgency let alone the political will, though.

Just to solidify various pesimistic opinions around here, let me make a hypothetical scenario. Suppose an object the size of a moon was detected and its path was repeatedly shown to coincide with that of the Earth. In 30 years. A mass the size of a moon could not be obliterated and its path could not be significantly affected by nuclear explosions. So. The only way to save the human race would be if we could launch long term viable space capsules.

Does anyone seriously believe that we could not do so?

 

[kuroyume0161]

Yes, 30 years wouldn't be nearly enough. It took nearly twenty to get to the Moon with a blank check the size of the US's national income.

That and the destruction of the planet wouldn't really be incentive would it? Or do you expect to evacuate all six (or seven) billion people. What incentive is there for everyone to pull together if only a few dozen or hundred will survive?

 

[DanishDynamite]

Yes, 30 years wouldn't be nearly enough. It took nearly twenty to get to the Moon with a blank check the size of the US's national income.

Hardly. It took less than 10 years and the check was not blank but amounted to just about 60 billion dollars over 10 years. A pittance compared to the US national income at the time.

That and the destruction of the planet wouldn't really be incentive would it? Or do you expect to evacuate all six (or seven) billion people. What incentive is there for everyone to pull together if only a few dozen or hundred will survive?

To save the human race?

 

[kuroyume0161]

Hardly. It took less than 10 years and the check was not blank but amounted to just about 60 billion dollars over 10 years. A pittance compared to the US national income at the time.

That's basically blank. In 2005 dollars, it cost 183 billion dollars for the entire Apollo project. That's still a large chunk of change (and about 40% of NASA's total budget). So, that would be 457.5 billion dollars (2005USD) over 10 years (46 billion/annum) for NASA's budget. I'll qualify that not all of this went to Apollo, but it shows the amount of money for the space missions for that decade of time. So, to save the human race, we'd need at least 100 times that (50 trillion dollars - tell me that's nothing (it's nearly five times the US economy of 2004)).

To save the human race?

For what? A cold, slow death in space? Where are you sending this neo-Noah's ark? Moon? To Mars? Titan? Another star (none of which is known to have inhabitable planets)?

NASA doesn't plan things for two years and then launch. Most robotic missions are in planning and development stages for at least a decade, with another decade to get the go ahead, build, and launch.

We have no rocket capable of launching, say, 50 people into space on a long-term (permanent) space mission. The Saturns are rust and noone knows how to rebuild one. The current large booster rockets cannot do more than 30 tons. On such short notice, we'd need something capable of 30000 tons (fuel, supplies for about 50-100 years, oh, and the humans)! Good... luck...