Artificial gravity in long term space travel

[csmyth3025]

Regarding the subject of this thread, there are several possible scenarios that can be associated with the notion of "long term space travel". One idea is that the participants are going from a planet (Earth?) to another planet for settlement or exploration. If the purpose is exploration, the people involved will probably want to return to Earth. Whether they stay on their new planet (Mars?) or return to Earth, they will not want their skeletal and muscle strength degraded by a lengthy zero-g transit. The question of gravity on generational ships travelling to another planetary system is too speculative to even think about at this stage.

If we look farther into the future, there may well be space ships (and space crews) that never return to any planetary surface. The individuals comprising such crews may prefer to spend their "golden years" on a low-g moon or, perhaps, a low or zero-g space colony. In fact, they may have grown up in a colony on a moon or in space.

I can envision a time far in the future when mankind may become differentiated into "spacers" who spend their entire lifetime in space at zero-g or low-g, and "terrestrials" who inhabit planetary surfaces or travel to space stations and then return to their planets. The possible physiological "evolution" of spacers is hard to predict, but those things that they don't need and don't use in space (bone and muscle strength, for instance) will no doubt diminish. What effects such an environment will have on infants and children - if these space ships turn out to be a "family business" - is also hard to predict. After many generations they may turn out to be the frail, large headed "aliens" that have been depicted by the popular media.

Chris

 

[uberhund]

Hitler's Germany comes to mind when discussing manned space flight?

Yes. It does. Surely I'm not the only one who considers Werner von Braun one of the fathers of manned space flight.

Artificial gravity may not be necessary for trips throughout the solar system but it would help to keep the astronauts in shape.

Not just in shape, but alive. Trips throughout the solar system would take decades, unless your plan was to abandon the astronauts once they arrived at their destination. Consequently, your craft will need to be equipped with married men and women, hospitals, nursery schools, elementary, middle, and high schools to prepare the successive generation to take over when the original astronauts eventually die off. Where it possible to even contemplate this ridiculous scenario, the astronauts returning from a trip "throughout the solar system" would be people we've never met.

 

[Yuri_Armstrong]

Artificial gravity may not be necessary for trips throughout the solar system but it would help to keep the astronauts in shape.

Not just in shape, but alive. Trips throughout the solar system would take decades, unless your plan was to abandon the astronauts once they arrived at their destination. Consequently, your craft will need to be equipped with married men and women, hospitals, nursery schools, elementary, middle, and high schools to prepare the successive generation to take over when the original astronauts eventually die off. Where it possible to even contemplate this ridiculous scenario, the astronauts returning from a trip "throughout the solar system" would be people we've never met.[/quote]

It depends on where they're going. A trip to Mars may be as quick as 5 months, in which case artifical gravity may not even be used for sake of convenience. And what makes you think it would take decades to get somewhere in the solar system, even to the Kuiper belt? The New Horizons probe will only take 9 years to get to Pluto, by the time we send a manned mission there I'm sure that the speed of it will be much faster.

That brings up an interesting idea. If our ability to travel to destinations much faster increases at a constant rate, the issue of weightlessness may become moot. Astronauts and cosmonauts already spend 6 months on the ISS and come back in good shape, even if their bones and muscles have thinned out some.

 

[Valcan]

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Well first off, all of this depends on available technology as well as the destination. If something more powerful than a vasimr is used you may be able to get there in very little time indeed.

Also what are the constraints industry wise. If your going to build ships like that it would make much more sense to just build large station archologies to house workers, their families and all there needs.

Then use the resources extracted to build your ship.

Plus what if you built large toroid station or a large station tubular in structure? spin them up and you have artifical gravity. And as our ability to geneticly manipulate our offspring comes into effect in i'd say the next 50 yrs you may see people engineered for Low g enviroments.
And as others have said a spaceship is in many ways nothing more than a station with engines. Heck it doesnt even need to have engines just needs a tug.

 

[neutrino78x]

]Not just in shape, but alive. Trips throughout the solar system would take decades, unless your plan was to abandon the astronauts once they arrived at their destination. Consequently, your craft will need to be equipped with married men and women, hospitals, nursery schools, elementary, middle, and high schools to prepare the successive generation to take over when the original astronauts eventually die off. Where it possible to even contemplate this ridiculous scenario, the astronauts returning from a trip "throughout the solar system" would be people we've never met.

Dude...trips within the solar system would not take decades. Voyager 2 took only 12 years to get to Neptune, so I guess if your definition of "decades" is 24 years, you would be right, but most people think of 40 or 50 years. Presumably, if we sent humans to Neptune, we would either use a faster propulsion system (nuclear thermal, etc.) or put people in suspended animation somehow, as in 2001: A Space Odyssey.

You don't use a generation ship to go within the solar system; that would be for going to another star, if you did it all.

--Brian

 

[neutrino78x]

Plus what if you built large toroid station or a large station tubular in structure? spin them up and you have artifical gravity.

According to uberhound, that is scientifically impossible. :roll:

--Brian

 

[csmyth3025]

Plus what if you built large toroid station or a large station tubular in structure? spin them up and you have artifical gravity.

According to uberhound, that is scientifically impossible. :roll:

--Brian

A large rotating toroidal space station is scientifically impossible? I didn't know that. Can you explain?

Chris

 

[uberhund]

A large rotating toroidal space station is scientifically impossible? I didn't know that. Can you explain?

I believe the reference above is to the combination of physics, economics, engineering, and ethics that renders any type of long-term space travel impossible (whether toroids or any other configuration).

But, if one is just dreaming up plots for movies, without having to actually implement any working models to the contrary, then don't let the facts spoil the fun. I like space movies too.

Dude...trips within the solar system would not take decades. Voyager 2 took only 12 years to get to Neptune, so I guess if your definition of "decades" is 24 years, you would be right, but most people think of 40 or 50 years.

Don't forget to add the years the Neptune travelers would remain on station once they arrive. After a 12 year journey (using your number), they will not want to turn around immediately and come back home, even if it were possible. But space travel doesn't work that way. Given orbital alignment and fuel budgets involved, the on-station time will have to be years. But let's be aggressive. Let's say the round trip could be done in 30 years. What percentage of Space.com fans, living in the comfort of our natural gravity and radiation shielding, will be alive and fully functional in 30 years? Why would the ratio be any different for your hypothetical Neptune travelers? The attrition rate over the mission life requires births in space.

Presumably, if we sent humans to Neptune, we would either use a faster propulsion system (nuclear thermal, etc.) or put people in suspended animation somehow, as in 2001: A Space Odyssey.

The same combination of physics, economics, engineering, and ethics rule out any of this. I loved the movie, but Kubrick and Clarke did more for film making than prognostication. A heroic try, but they got almost nothing right, and they were attempting to predict a mere 20 or so years into the future.

 

[James_Bull]

A large rotating toroidal space station is scientifically impossible? I didn't know that. Can you explain?

I believe the reference above is to the combination of physics, economics, engineering, and ethics that renders any type of long-term space travel impossible (whether toroids or any other configuration).

But, if one is just dreaming up plots for movies, without having to actually implement any working models to the contrary, then don't let the facts spoil the fun. I like space movies too.

Rotating a module scientifically impossible?
Okay lets have a look at your insurmountable combination.
Physically possible = Yes, anyone who says otherwise is competely uninformed.
Economics = Very possible, spinning a module shouldn't cost that much at all.
Engineering = Yep, rather easily actually in a 'module, string, counterweight' config like in Mars Direct.
Ethics = What has this got to do with it being scientifically possible?! And for that matter, what ethics?

I don't mean to be rude but after reading a few of your incredible posts it becomes clear that you are obviously still suffering from the wonderland of the future that was portrayed to you during the golden years of Apollo. A time when by now, it was more or less assumed that we'd all be living on the moon; occasionally venturing off for the odd holiday to climb Olympus Mons. In the realisation that this definately will not happen in your lifetime, you make bold and rash statements here (since when is spinning a module in space impossible?!) and feel utter resentment toward all manned spaceflight; "nothing will happen in space his side of Armegeddon"; I think you've been watching too many space movies yourself.
You're bursting with bitterness that none of the promises have been fufilled, but please take your apathy and negativity elsewhere!

 

[uberhund]

Physically possible = Yes, anyone who says otherwise is competely uninformed.

What a relief then that I can be counted as one of the informed. As we both know, rotation of anything in space, on Earth orbit or otherwise, happens almost on its own with no need for artificial help. Nevertheless, "Physics still renders long term space travel impossible."

Economics = Very possible, spinning a module shouldn't cost that much at all.

It's always cheap when you're not the one paying for it. The fact is, even failed LEO projects like STS require nation-crippling budgets. Recall von Braun's and Gus Grissom's famous quotes on the subject that go approximately like "No bucks, no Buck Rogers." This just in: space travel is not getting cheaper. It's getting incredibly more expensive. Don't confuse the dropping cost of Guitar Hero with technologies that actually enable space travel.

Engineering = Yep, rather easily actually in a 'module, string, counterweight' config like in Mars Direct.

Ouch. I wouldn't walk into a room of aerospace engineers and physicists and tell them you think what they're doing is rather easy. As you evidently read from my earlier posts, they only make it look easy, and that's why I love engineering and physics.

Ethics = What has this got to do with it being scientifically possible?! And for that matter, what ethics?

Almost anything scientifically worthwhile incurs some ethics issues. For example, it may be scientifically possible to clone humans, but is it ethical? Similarly, in postulating long-term space flight, very, very, serious ethics issue quickly arise. Is it ethical to send humans into space to eventually die from radiation or lack of proper medical attention, even if they volunteer to do so? Is it ethical to bring a child into the universe on a space craft, when that child has no vote in the matter? Is it ethical to impose the crushing resource burdens on a nation to chase long-term human spaceflight when there is absolutely zero return for the investment? I don't know the answers either, but I know they must be part of the public debate.

you make bold and rash statements ... and feel utter resentment toward all manned spaceflight; "nothing will happen in space his side of Armegeddon."

It's funny you mention resentment. I was thinking of that exact word as I read your post. But not to worry. I remember the time I found out about Santa Clause. I wanted everyone to leave the room too. And for what it's worth, my actual wording was closer to "humans will never colonize again, this side of Armegeddon." But thanks for trying - it gives me a chance to repeat it and I was rather proud of that one.

I don't mean to be rude but after reading a few of your incredible posts

Yes, but the point is, you've been reading them. Who wants to read a post that doesn't posit something new and provoke a response? For my money, the ideas in Umberto Eco's library I haven't read or thought about are the most interesting. Who needs the others?

but please take your apathy and negativity elsewhere!

Well, judging from the number of posts I made just last week, I'm not a very competent apathetic. As for negativity - yes, when it comes to missed opportunities and pointless waste, I am negative. As should we all.

On the other hand, I remain enthralled with the wonderful, amazing, and pure fun to be had with building, making, exploring, discovering, answering. All in front of us, and on this I am very positive.

So no. I'm not going elsewhere. But at least you said please.

 

[Valcan]

[/quote="uberhund.][/quote]

I see no reason for it to be impossible. Its not impossible to build a station capable of attaining maybe 3/4's of a g or more depending on the size.
Space travel threw our solar system isnt impossible.
Out of it......not impossible, but not logical for a great while. It would simply require a shipe of amazing dimensions and technology.
I see no reason why we couldnt see the solar system dotted with colonies and earth ringed by orbital habitats in the next 100 years.

In MY mind atleast it would make better sense to build a large orbital station first before colonizing the rest of the system. That way we could test many technologies and systems before sending them WAY out. Also this could function as the industrial tender box for the construction of further stations and ships.

 

[Yuri_Armstrong]

And that's what makes the ISS so great. A huge laboratory in space where they can get plenty of science work done and give astronauts a destination to go to. It's an incredible engineering marvel, it just speaks to what NASA and the other space programs can accomplish. And the possibility of new modules like the MPLM and CAM make the place even more interesting! I say we hang on to the ISS as long as we can and keep expanding on it. Once we have more manned orbital infrastructure hopefully we will be able to do away with Earth based launches. They are very dramatic and inspiring but escaping gravity requires lots of fuel, mass and money.

 

[SteveCNC]

Don't worry about it James , I've asked the same question a few times in this thread as have others but when no answer can be given that isn't sarcasm or off the subject entirely and actually makes sense you have to reach the point of not caring anymore about certain peoples thoughts . We all know the only difference between a ship with , and a ship without artificial gravity , is the attitute control software and possibly the basic configuration however it takes no more physical hardware to accomplish it , it's all in the software , since you have multiple attitude control jets/wheels all you really need do is change the software a bit to allow for spin . As to the basic configuration I refer to earlier in this post , it only requires a floor plan that works and a diameter about the center of rotation that is large enough to not cause problems . The same ship could be spun or not spun is my point and at that point is just the attitude control doing the work .

 

[rockett]

Don't worry about it James , I've asked the same question a few times in this thread as have others but when no answer can be given that isn't sarcasm or off the subject entirely and actually makes sense you have to reach the point of not caring anymore about certain peoples thoughts . We all know the only difference between a ship with , and a ship without artificial gravity , is the attitute control software and possibly the basic configuration however it takes no more physical hardware to accomplish it , it's all in the software , since you have multiple attitude control jets/wheels all you really need do is change the software a bit to allow for spin . As to the basic configuration I refer to earlier in this post , it only requires a floor plan that works and a diameter about the center of rotation that is large enough to not cause problems . The same ship could be spun or not spun is my point and at that point is just the attitude control doing the work .

Absolutely right Steve! Structural integrity for connecting trusses shouldn't be an issue with today's materials either. Carbon fiber comes to mind.

Here's a link the nay sayer(s) might like: http://theflatearthsociety.org/ :lol:

 

[neutrino78x]

As we both know, rotation of anything in space, on Earth orbit or otherwise, happens almost on its own with no need for artificial help. Nevertheless, "Physics still renders long term space travel impossible."

So, how do you explain the Pioneer and Voyager long term space missions? A manned spacecraft for long term missions would simply be a larger version.

You need to remove the word "physics" from that statement. Nothing in the laws of Newton, Einstein, Kepler, et al., prevent us from building a ship that travels long distances in space. Please show me the physical law stating that an object cannot be accelerated to a given speed, below that of light, and reach a destination in space.

There may be economic issues, but they are not insurmountable.

It's always cheap when you're not the one paying for it. The fact is, even failed LEO projects like STS require nation-crippling budgets.

SpaceX seems to get by just fine. Federal dollars will accelerate the commercial exploitation of space, however, and I endorse using them to do so.

This just in: space travel is not getting cheaper. It's getting incredibly more expensive.

The X Prize Foundation would beg to differ with you, I imagine. As would the Commercial Space Flight Federation.

Almost anything scientifically worthwhile incurs some ethics issues. For example, it may be scientifically possible to clone humans, but is it ethical?

The scientific value of cloning a human is not clear. The medical value of cloning specific organs, yes. But it is not clear what scientific value would be gained from cloning an entire human.

Similarly, in postulating long-term space flight, very, very, serious ethics issue quickly arise. Is it ethical to send humans into space to eventually die from radiation or lack of proper medical attention, even if they volunteer to do so?

Why would we do that? Perhaps for a military manned mission, but there are no such missions yet.

As a US Navy submariner, I volunteered to be exposed to radiation, and other forms of danger, including the sea pressure at great depth, the violence of storms at sea, the possibility of death from a hostile torpedo, a fire aboard the submarine, flooding aboard the submarine (both of which occurred during my tour of duty, although they were minor incidents), impacting an uncharted mountain beneath the sea (they form often, from volcanic activity), and many others. You must volunteer specifically for submarine duty, btw; they can put you whichever type of surface ship they want, but to go on a submarine crew, you have to volunteer.

People volunteer to do dangerous things for their country all the time.

Is it ethical to bring a child into the universe on a space craft, when that child has no vote in the matter?

That would be the decision of the parents. Unless you're advocating generation ships, the need for which is in question. Most argue that we would never send a generation ship as a government mission; we would design spacecraft which are fast enough to reach the destination in a reasonable time, or we would put the crew in suspended animation.

Generation ships are more of a science fiction construct.

Is it ethical to impose the crushing resource burdens on a nation to chase long-term human spaceflight when there is absolutely zero return for the investment?

Well, in my opinion, the government should not send humans on a dangerous space mission for no apparent reason. That is the role of private enterprise and private individuals.

And for what it's worth, my actual wording was closer to "humans will never colonize again, this side of Armegeddon." But thanks for trying - it gives me a chance to repeat it and I was rather proud of that one.

It is complete nonsense. Had you said "the government will never colonize again, this side of armageddon", I would agree, as government never colonizes. Private individuals do.

Jamestown Settlement, the first British colony in North America, was not a mission of His Majesty's Royal Navy. It was private individuals who paid for the trip.

--Brian

 

[uberhund]

So, how do you explain the Pioneer and Voyager long term space missions? A manned spacecraft for long term missions would simply be a larger version.

Using the word simply and manned spacecraft in the same sentence is known to cause Werner von Braun to spin in his grave, like an object adrift in space.

Nothing in the laws of Newton, Einstein, Kepler, et al., prevent us from building a ship that travels long distances in space. There may be economic issues, but they are not insurmountable.

Yes, they are insurmountable. Remember that all money is merely congealed energy. The accumulation and sublimation of money follows the same physical laws of thermodynamics as described by Newton. Achieving even a small fraction of the speed of light for a round trip journey, sadly, is beyond the money congealing capability of an entire planet.

The X Prize Foundation would beg to differ with [the statement that spaceflight is getting increasingly more expensive].

Would they? Have you tried to buy any helium lately? How about man-rating a booster? Are US governing agencies easing requirements for certification? Is Burt Rutan finding space tourism easier and Richard Branson cheaper than either of them originally thought?

As a US Navy submariner, I volunteered ... [to be] on a submarine crew, you have to volunteer. People volunteer to do dangerous things for their country all the time.

Thank you for your service to the country. Seriously. You have my respect and gratitude.

[Putting a child in a risky situation] would be the decision of the parents.

Er. No. A civilized culture does not sit by and let parents make those decisions. Parents who voluntarily put a child at risk get put in jail, and lose their children. Gandhi said a society can be judged by the way it treats its children.

we would design spacecraft which are fast enough to reach the destination in a reasonable time, or we would put the crew in suspended animation.

Only on a green screen stage in Hollywood

Generation ships are more of a science fiction construct.

Yep. We agree.

It is complete nonsense. Had you said "the government will never colonize again, this side of armageddon", I would agree, as government never colonizes. Private individuals do.

Hm. Private individuals like the Rev. Jim Jones in Jonestown, Guyana? Sorry, that may be a bad example. How about Biosphere? No, that one tanked too. Heaven's Gate? I believe I read somewhere that they colonized Comet Hale-Bopp. Please provide a better one if these don't work.

Jamestown Settlement, the first British colony in North America, was not a mission of His Majesty's Royal Navy. It was private individuals who paid for the trip.

But that was then. This is now. Earth is out of the colonization business, this side of World War III, because, it turns out, people don't like having their geopolitical boundaries defined at will by foreigners. Go figure.

 

[Yuri_Armstrong]

Can't say never in a science forum. The issues you listed are complicated but they can be worked out. uberhund, check your inbox, I sent you something that may change your mind

 

[uberhund]

Thanks, Yuri. A response is in process.

 

[defiant101]

you guys keep talking this is good stuff i like this debate, i am supporting neutrino and yuri....though uberhand is making very valid points, he is just making too many absolute statements.....you live in the 21st century to say long term space travel is impossible and will never happen, and colonization of moon or mars or whatever will never happen ever is just too much of an absolute statement, i can speak about my time,this century or maybe the next century, the few centuries coming after that but i would never say never lol.

though again uberhand has valid points.

and in the end i understand when you look at the numbers, it becomes clear that it is easier said than done. i do not know but something about quitting and just saying well we will never do it and its impossible, and then quitting man that would be the worst. i am not even an optimistic person, but there is a whole universe out there with a lot of resources, and of course for survival. i just wish cost was lower for launching cargo. spaceflight would be a lot more relevant lol.

just my last words i do not post many things but i could not help it lol. there are 2 choices...die or not die....i choose not die, and if it is almost certain that i will die i will try my best not to die and work with my chances and with what i got.the thing is it is not almost certain we have to die here we can make a choice to to survive if we would spread out of course it is easy for me to say this since i am not the scientist or engineer who is making all this happen. but as soon as i get my degree and get a better job with my degree i plan on donating whatever i can. maybe to xprize lol. i am not really a technical guy like you guys i am just a regular average guy who is mesmerized by the universe, oh i do know basic concepts of course like rotational gravity simulation, and slingshots. just not the deep technical stuff you guys are talking about, well hopefully i did not make myself look like an idiot saying all this lol .

OH YEAH you guys please keep going and debating this is great stuff

 

[uberhund]

Thanks for the kind words and encouragement, Defiant. Not to worry, I don't expect either Yuri or I to throw in the towel any time soon.

In spite of our differences, though, I guarantee we both agree that space is a wonderful place for humans to explore and understand.

Meanwhile, I'm pleased you're thinking of challenges like XPrize. These cash-based challenges are a win-win for the world; In fact, I see a future where NASA administers and referees xPrize-like awards (in DARPA fashion) for all manner of categories. I hope to see your avatar as a prize taker in one of them.

 

[defiant101]

if i become lucky and if i ever get rich, then maybe then i can call you guys and we can work on a project we can get space.com to get us popular........lol just wishful thinking lol, but hey maybe one day if that ever happens that would be fun and awesome lol . man i should have posted on this forum and other space forum its just that every time i write i can not seem to stop lol. space.com should have a chat room or something you get to talk more lol....anyways i been rambling enough......alright on with the topic, hopefully there is more posts i love reading this stuff

 

[Yuri_Armstrong]

How old are you defiant? Do not bet on becoming super rich if you want to make a significant contribution to HSF. I like your enthusiasm and I would reccomend you put it into studying science and math and hopefully getting a degree in one of those fields.

 

[defiant101]

i do not plan on becoming even rich, whatever i can i would donate it, but i am starting some plans and i need investments for some stuff my friend and i wanna do in our old country we were born in. don't worry i am not stupid i will not get rich in few days maybe not even months and years, i might not even become rich, but whatever i can get i would donate to xprize or something. i am sure i can get profits just do not know how much profits in our native country.i am 19, well basically 20 in 1 month lol. anyways enough about me....everyone keep talking your debate and inputs are very interesting .....oh on a side note, yuri thanks for saying i am enthusiastic but honestly its my last option, i got no choice but to be enthusiastic lol i wish spaceflight was more relevant and more advanced instead of having some of it's research and experiments canceled like we all here do.......oh yeah and just my 2 cents on the topic that yes artificial gravity as in rotational gravity simulation is possible for long term flight, but from what i know the spinning section has to be pretty large to make it feel like earth gravity, for mars i am assuming it can be smaller though then you might get a little sick because the smaller it is the more it has to spin.......man once i start typing i can not stop i deciding to stop typing awhile ago but i kept going lol

 

[Yuri_Armstrong]

Actually the sickness is caused by the rate of spin, not the diameter of the torus. Though if the diameter is small enough the gravity at your feet would be different than that at your head so you would probably get sick from that too. I've seen the posts about people getting used to 4 RPMs but I think it's better to play it safe and keep it at a max of 1.5 or 2 RPMs. We do not know how much gravity is needed to sustain a reasonably health human body. If its as low as .16 G as on the moon then that's great, you wouldn't need the torus diameter to be too big and the rpm wouldn't have to be too high. This is why we need modules like CAM attached to the ISS. We've got decades of zero-g research, but practically none on Martian and Lunar G except for that experienced during Apollo and on the vomit comet.

 

[defiant101]

yeah and the lower price tag for a smaller spinning section that has less diameter that would be close to mars and moon gravity is sure way to make everyone and specially politicians go for it.....lol if it were only that easy....but yeah as long it keeps the human body in shape, man we should have been doing more research into this, too bad for budget cuts, i would rather see my tax doillars that they take from me go into nasa and spaceflight in general than iraq war or the drug war....but ehhhh this is not a place for politics well it directly and indirectly is lol but i dont wanna talk about that stuff