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Another problem with longer flights
In any trip for humans beyond the moon (mars and beyond)
artificial gravity is a necessity. Space.com reports: [1] quote Astronauts that spend long months aboard the International Space Station lose bone strength faster than previously thought and have a higher risk of breaking their hips later in life, a new study reports. A survey of 13 space station astronauts found that their bone strength dipped by at least 14 percent on the average during their half-year stays aboard the orbiting laboratory. Three of the astronauts lost up to 30 percent of their bone strength during their long-duration spaceflights, putting them on par with the bone strength of older women with osteoporosis on Earth, the study reported. end quote If in only 6 months trips they lose 14% of their bone strength, in a trip of 2 years (the minimum time for a Mars trip) the strength of their bones would disminish in such a measure that it would be a one way trip only. They could not resist earth gravity when they come back. This means that artificial gravity is a must for any trip that takes more than 2-3 months. Note that the risk of breaking their bones much later in life increases since apparently is very difficult to get the lost strength back. This is another big problem with humans in space and with human spaceflight. [1] http://www.space.com/scienceastronom...ngth-loss.html -- jacob navia jacob at jacob point remcomp point fr logiciels/informatique http://www.cs.virginia.edu/~lcc-win32 |
#2
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Another problem with longer flights
Borked Pseudo Mailed wrote: The evolution of species on Earth has depended on gravity for billions of years. Why are we so ignorant to think that we can solve the adverse effects of weightlessness within a couple of decades? Why aren't we more pragmatic? Weight. Building something that spins and generates 1 g like in 2001 means its going to have to be huge, as studies have shown that unless it's around 400' in diameter the crew are going to get sick as they move around inside of it from having "up" constantly changing between their head and feet as they move from point to point on its periphery. This is going to cause dizziness and nausea. The centrifuge aboard the Discovery was only generating 1/6 g and even then it was way too small to prevent the astronauts from getting sick: http://www.visual-memory.co.uk/amk/doc/gaffe.html "And although the Discovery's centrifuge scenes are superbly executed, in the scene at Space Station Five it's quite obvious the actors in these scenes are descending a ramp as they walk 'around' the wheel of the station from the background to the foreground. The Discovery's 38ft. centrifuge itself is the object of some debate: Clarke and science advisor Ordway have admitted that, as impressive as it looks, the centrifuge would need to have been many times larger or the Corriolus effect in the inner ear would have caused uncontrollable nausea in the crew members. There are also many questions as to the effect of the torque of rotation on objects inside a rapidly rotating centrifuge. According to Ordway's writings, the decision was made to have the centrifuge generate 1/6 G lunar gravity. Of course, rapid exercise such as Poole's running would be impossible in such low gravity." Pat |
#3
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Another problem with longer flights
Pat Flannery wrote:
Borked Pseudo Mailed wrote: The evolution of species on Earth has depended on gravity for billions of years. Why are we so ignorant to think that we can solve the adverse effects of weightlessness within a couple of decades? Why aren't we more pragmatic? Weight. Building something that spins and generates 1 g like in 2001 means its going to have to be huge, as studies have shown that unless it's around 400' in diameter the crew are going to get sick as they move around inside of it from having "up" constantly changing between their head and feet as they move from point to point on its periphery. This is going to cause dizziness and nausea. The centrifuge aboard the Discovery was only generating 1/6 g and even then it was way too small to prevent the astronauts from getting sick: http://www.visual-memory.co.uk/amk/doc/gaffe.html Exactly. That is why human space travel will have to wait until we can build huge spaceships. To just go to Mars, with a 2-3 year stay in space, we would need a huge, rotating, ship, shielded from space radiation by several meters of water. This will not be feasible with current technology. We will need a radically new way of accessing space before such ships become possible. With the *current* knowledge we have, automatic robotic exploring is the only way to go. -- jacob navia jacob at jacob point remcomp point fr logiciels/informatique http://www.cs.virginia.edu/~lcc-win32 |
#4
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Another problem with longer flights
"Borked Pseudo Mailed" wrote in message
d.net... "jacob navia" wrote in message ... In any trip for humans beyond the moon (mars and beyond) artificial gravity is a necessity. Space.com reports: [1] quote Astronauts that spend long months aboard the International Space Station lose bone strength faster than previously thought and have a higher risk of breaking their hips later in life, a new study reports. A survey of 13 space station astronauts found that their bone strength dipped by at least 14 percent on the average during their half-year stays aboard the orbiting laboratory. Three of the astronauts lost up to 30 percent of their bone strength during their long-duration spaceflights, putting them on par with the bone strength of older women with osteoporosis on Earth, the study reported. end quote If in only 6 months trips they lose 14% of their bone strength, in a trip of 2 years (the minimum time for a Mars trip) the strength of their bones would disminish in such a measure that it would be a one way trip only. They could not resist earth gravity when they come back. This means that artificial gravity is a must for any trip that takes more than 2-3 months. Note that the risk of breaking their bones much later in life increases since apparently is very difficult to get the lost strength back. This is another big problem with humans in space and with human spaceflight. I've been advocating artificial gravity for many many years now, but it seems NASA is suffering from some sort of tunnel vision, convinced they can solve the ill effects of weightlessness by medicines and exercise. That is why '2001 A Space Odyssey' is still one of my favorite movies, because both the space station and Discovery used artificial gravity systems, and it seems people in the 60's were far better informed than we are. Decades of research has come up naught, there *is no* way to combat the absence of gravity but to produce it artificially. The evolution of species on Earth has depended on gravity for billions of years. Why are we so ignorant to think that we can solve the adverse effects of weightlessness within a couple of decades? Why aren't we more pragmatic? ================================================== = Well, researchers are working on it. I can't speak for NASA, nor do I think things are so simple our 'we' can include everyone. In the mean time, Robert Zubrin answers this and very many other relevant questions in his book, "The Case for Mars" (1996). There's lots of good resources in cyberspace but I think Zubrin's book is the best place for someone to start who wants to acquire the resources to do something constructive as vs recycling old words. Titeotwawki -- mha [sci.space.policy 2009 Jan 28] |
#5
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Another problem with longer flights
Martha Adams wrote: Well, researchers are working on it. I can't speak for NASA, nor do I think things are so simple our 'we' can include everyone. In the mean time, Robert Zubrin answers this and very many other relevant questions in his book, "The Case for Mars" (1996). There's lots of good resources in cyberspace but I think Zubrin's book is the best place for someone to start who wants to acquire the resources to do something constructive as vs recycling old words. There's a way to do it...you don't need the whole wheel, just something spinning 400 feet or more from its center of rotation. Which means you can hang the thing you want to have gravity on the end of a 400 foot cable to the center of rotation with a counterweight of some sort on the opposite side of it...which can be another crewed area or something like a reactor. My nuclear-thermal/ion propulsion spaceship idea (model he http://www.starshipmodeler.com/gallery/pf_disc.htm ) ....uses this by having the whole ship rotate around its center, where the de-spun ion engines and low gravity areas are located. the crew lives at the front end, and over 800 feet away are the nuclear power plant and nuclear-thermal engines serving as a counterweight. The de-spun ion engines and observation and communication gear are at the center of rotation, sliding back and forth on tracks to keep then centered as the center point of rotation changes due to loss of mass of expendables at either end, or the secondary ships docking and undocking as they explore the moons of Saturn. Although it's never shown in "2001", the movie's Discovery* is perfectly designed to do this also as you can see in the rotating scenes in "2010" where they board the Discovery from the center communications area. I wonder if the original idea was to have it rotating in the movie, as it would hearken back to the ape throwing the rotating bone into the air at the beginning of the movie. * Mine is called Discovery because NASA decided to name it after the one in the movie and the Shuttle, the way they named the Shuttle Enterprise after the one in Star Trek. Pat |
#6
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Another problem with longer flights
On Wed, 28 Jan 2009 22:30:42 +0100, jacob navia
wrote: Building something that spins and generates 1 g like in 2001 means its going to have to be huge, as studies have shown that unless it's around 400' in diameter the crew are going to get sick as they move around Exactly. That is why human space travel will have to wait until we can build huge spaceships. Not really - put two ship-sections on the end of a tether, and swing them around their center-of-mass like a bolo. You've got gravity AND a small ship. |
#7
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Another problem with longer flights
On Jan 28, 4:35�pm, "Martha Adams" wrote:
"Borked Pseudo Mailed" wrote in messagenews:e7b782c2dc2312c4b1e98631cfe752c0@pseud o.borked.net... "jacob navia" wrote in message ... In any trip for humans beyond the moon (mars and beyond) artificial gravity is a necessity. Space.com reports: [1] quote Astronauts that spend long months aboard the International Space Station lose bone strength faster than previously thought and have a higher risk of breaking their hips later in life, a new study reports. A survey of 13 space station astronauts found that their bone strength dipped by at least 14 percent on the average during their half-year stays aboard the orbiting laboratory. Three of the astronauts lost up to 30 percent of their bone strength during their long-duration spaceflights, putting them on par with the bone strength of older women with osteoporosis on Earth, the study reported. end quote If in only 6 months trips they lose 14% of their bone strength, in a trip of 2 years (the minimum time for a Mars trip) the strength of their bones would disminish in such a measure that it would be a one way trip only. They could not resist earth gravity when they come back. This means that artificial gravity is a must for any trip that takes more than 2-3 months. Note that the risk of breaking their bones much later in life increases since apparently is very difficult to get the lost strength back. This is another big problem with humans in space and with human spaceflight. I've been advocating artificial gravity for many many years now, but it seems NASA is suffering from some sort of tunnel vision, convinced they can solve the ill effects of weightlessness by medicines and exercise. That is why '2001 A Space Odyssey' is still one of my favorite movies, because both the space station and Discovery used artificial gravity systems, and it seems people in the 60's were far better informed than we are. Decades of research has come up naught, there *is no* way to combat the absence of gravity but to produce it artificially. The evolution of species on Earth has depended on gravity for billions of years. Why are we so ignorant to think that we can solve the adverse effects of weightlessness within a couple of decades? Why aren't we more pragmatic? ================================================== = Well, researchers are working on it. �I can't speak for NASA, nor do I think things are so simple our 'we' can include everyone. �In the mean time, Robert Zubrin answers this and very many other relevant questions in his book, "The Case for Mars" (1996). �There's lots of good resources in cyberspace but I think Zubrin's book is the best place for someone to start who wants to acquire the resources to do something constructive as vs recycling old words. Titeotwawki -- mha �[sci.space.policy 2009 Jan 28]- Hide quoted text - - Show quoted text - or cut the travel time dramatically by using nuclear engine for mars mission. a few months each way plus time on mars. pair a hot nuke engine with a small cargo pod for fast emergency supplies. although i agree robotic exploration is best and could be used to leapfrog AI and other robotics. |
#8
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Another problem with longer flights
"Len Lekx" wrote in message
... On Wed, 28 Jan 2009 22:30:42 +0100, jacob navia wrote: Building something that spins and generates 1 g like in 2001 means its going to have to be huge, as studies have shown that unless it's around 400' in diameter the crew are going to get sick as they move around Exactly. That is why human space travel will have to wait until we can build huge spaceships. Not really - put two ship-sections on the end of a tether, and swing them around their center-of-mass like a bolo. You've got gravity AND a small ship. And other issues. Such as how do you perform in-flight maneuvers? And what happens if you can't keep the line taught. We definitely need to do more research in this area before we can claim it's easy. -- Greg Moore Ask me about lily, an RPI based CMC. |
#9
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Another problem with longer flights
jacob navia wrote:
:Pat Flannery wrote: : : : Borked Pseudo Mailed wrote: : The evolution of species on Earth has depended on gravity for : billions of years. Why are we so ignorant to think that we can solve : the adverse effects of weightlessness within a couple of decades? Why : aren't we more pragmatic? : : Weight. : Building something that spins and generates 1 g like in 2001 means its : going to have to be huge, as studies have shown that unless it's around : 400' in diameter the crew are going to get sick as they move around : inside of it from having "up" constantly changing between their head and : feet as they move from point to point on its periphery. : This is going to cause dizziness and nausea. : The centrifuge aboard the Discovery was only generating 1/6 g and even : then it was way too small to prevent the astronauts from getting sick: : http://www.visual-memory.co.uk/amk/doc/gaffe.html : : :Exactly. That is why human space travel will have to wait :until we can build huge spaceships. : :To just go to Mars, with a 2-3 year stay in space, we would need :a huge, rotating, ship, shielded from space radiation by several :meters of water. This will not be feasible with current technology. : :We will need a radically new way of accessing space before such ships :become possible. : :With the *current* knowledge we have, automatic robotic exploring is the nly way to go. : You mean the current knowledge YOU have. The rest of us are somewhat brighter and better informed. No "huge, rotating, ship, [sic]" is required. A much smaller ship, a rope, and a counterweight will achieve the same end. -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
#10
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Another problem with longer flights
"Greg D. Moore \(Strider\)" wrote:
:"Len Lekx" wrote in message .. . : On Wed, 28 Jan 2009 22:30:42 +0100, jacob navia : wrote: : : Building something that spins and generates 1 g like in 2001 means its : going to have to be huge, as studies have shown that unless it's around : 400' in diameter the crew are going to get sick as they move around :Exactly. That is why human space travel will have to wait :until we can build huge spaceships. : : Not really - put two ship-sections on the end of a tether, and swing : them around their center-of-mass like a bolo. You've got gravity AND : a small ship. : :And other issues. Such as how do you perform in-flight maneuvers? : Reel in the weight, maneuver, reel it back out, and respin. : :And what happens if you can't keep the line taught. : Then you have much bigger problems, since that would mean that the basic laws of physics had broken down. -- "Ignorance is preferable to error, and he is less remote from the truth who believes nothing than he who believes what is wrong." -- Thomas Jefferson |
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