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Post by the light works on Dec 14, 2013 17:55:46 GMT
Just some inquiries about solar sails. Are solar sails rigid or are the frames they are on rigid? Can the orientation space craft be used to move through space dust? (e.g. head on large surface area, sideways, not much surface area) Just my small contribution, maybe the study of comets could yield mathematical computations that will help send something outside our solar system much faster. As to sending ourselves outside our solar system, sending DNA is actually very interesting. Would research into genetically creating organisms to survive and multiply on demand to tailor fit the expected trip be possible? Hope this helps solar sails have as much variety as traditional sails. in theory, you could even pattern a spacecraft after a traditional square rigger, if you wanted to waste the resources on aesthetics. |
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Post by rmc on Dec 14, 2013 18:45:51 GMT
I'd still like to test out a solar-streamer arrangement of some sort. Perhaps it would look a bit like a tassel: Many streamers stretched out way ahead of the craft. As they get a wave going through them, the efficiency of solar particles striking the array increases. Advantage: small forward cross-section, and fewer array cables. DIsadvantages: requires perhaps 15 times the square area of traditional solar sail?
(I'd like to better generalize the difference factor between a streamer like this one and a sail)
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Post by the light works on Dec 14, 2013 18:50:35 GMT
I'd still like to test out a solar-streamer arrangement of some sort. Perhaps it would look like a bit like tassel: Many streamers stretched out way ahead of the craft. As they get a wave going through them, the efficiency of solar particles striking the array increases. Advantage: small forward cross-section, and fewer array cables. DIsadvantages: requires perhaps 15 times the square area of traditional solar sail? (I'd like to better generalize the difference factor between a streamer like this one and a sail) I would think you could approximate the physics of solar sails with traditional wind devices. which leaves me wondering about the viability of a "sunmill" generating system. |
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Post by rmc on Dec 14, 2013 19:19:19 GMT
I think I see it, the light works!
A rotational array of sails. Would the array of rotational sails be powered in some way, or just spin freely as a result of solar pressure?
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Post by User Unavailable on Dec 14, 2013 20:38:13 GMT
I'd still like to test out a solar-streamer arrangement of some sort. Perhaps it would look a bit like a tassel: Many streamers stretched out way ahead of the craft. As they get a wave going through them, the efficiency of solar particles striking the array increases. Advantage: small forward cross-section, and fewer array cables. DIsadvantages: requires perhaps 15 times the square area of traditional solar sail? (I'd like to better generalize the difference factor between a streamer like this one and a sail) Typically on Earth, streamers are used to produce drag for stability. (example: kite tails, tails on improvised munitions, etc). The streamers catch just enough air to produce a little drag and/or add weight to keep the object to which they are attached oriented in the desired position. I've never seen an example of streamers used as a replacement for a sail here on Earth. It seems to me that the shape of streamers would allow the vast majority of usable "solar wind", to pass on by an be very inefficient. You could add more and more streamers to increase the amount of wind they catch, but then this adds size and weight and would rapidly become more a hindrance than an asset. At least to my way of thinking. |
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Post by Cybermortis on Dec 14, 2013 20:43:29 GMT
You do not want solar sails to rotate. The added stresses would require thicker, stronger and heavier materials and support structures - which reduces the efficiency of the sail and increases costs in a major way since you have to take that added mass into orbit at some point. You'd also need complex machinery both to allow the sails to physically rotate, and to counteract the rotational forces such a rig would apply to the rest of the space craft.
Remember that unlike a sailing ship a spacecraft doesn't have any external force or material that can absorb some of the unwanted motion imparted from the sails - meaning water. So any unwanted motion can only be counteracted from within the spacecraft itself. So that's either thruster arrays or a circular structure that rotates in the opposite direction to the sail to counteract the rotational forces. Both sort of counteract the basic idea of a solar sail as a cheap, light and energy 'free' form of propulsion.
If you want to get energy from sunlight you are much better served by using solar cells, which are cheaper easier and far more efficient.
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Post by rmc on Dec 14, 2013 21:35:09 GMT
Yeah, I don't really like the inefficiency of streamers, but I thought go ahead and use one (so the craft has a smaller frontal cross section) and then start the journey much closer to the home star in oder to get something of a boost of solar wind and who know maybe even a touch of a solar flare as well while we're at it. Then, once the acceleration is achieved, ditch the streamer (it would hover near the craft until braking took place or until it started hitting enough dust or what-have-you) If it hits dust after release the craft passes it (hopefully). If it hovers along side until braking, then once the craft is decelerating the streamer floats on ahead in the general direction of the target planet leaving the craft, as it is slowing.
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Post by the light works on Dec 15, 2013 0:48:48 GMT
I think I see it, the light works! A rotational array of sails. Would the array of rotational sails be powered in some way, or just spin freely as a result of solar pressure? the idea would be that it would rotate from the solar pressure, and turn a generator. as cyber says, there would have to be a counterforce to keep it from spinning the craft instead of the generator. I'm certainly not going tomake any claims of efficiency; as you might notice it came with a preface to the effect of "I wonder" a set of counterrotating solar sails might power a centrifugal gravity chamber, or a single set might rotate a cylindrical ship for artificial gravity while I am speculating on silly stuff, you might use a windsock instead of a streamer system for the sail. done properly, it could be rimless and self inflate; and a side effect might be that once cut loose, it might help shield the ship from debris. I'd be inclined to cut loose before the lines go slack - so it gets a slight acceleration away from the ship; which would let it lead at a greater distance, and have some kinetic energy available to deflect debris, before you have to worry about whether the ship plows through it or not. |
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Post by the light works on Dec 15, 2013 0:50:16 GMT
I'd still like to test out a solar-streamer arrangement of some sort. Perhaps it would look a bit like a tassel: Many streamers stretched out way ahead of the craft. As they get a wave going through them, the efficiency of solar particles striking the array increases. Advantage: small forward cross-section, and fewer array cables. DIsadvantages: requires perhaps 15 times the square area of traditional solar sail? (I'd like to better generalize the difference factor between a streamer like this one and a sail) Typically on Earth, streamers are used to produce drag for stability. (example: kite tails, tails on improvised munitions, etc). The streamers catch just enough air to produce a little drag and/or add weight to keep the object to which they are attached oriented in the desired position. I've never seen an example of streamers used as a replacement for a sail here on Earth. It seems to me that the shape of streamers would allow the vast majority of usable "solar wind", to pass on by an be very inefficient. You could add more and more streamers to increase the amount of wind they catch, but then this adds size and weight and would rapidly become more a hindrance than an asset. At least to my way of thinking. some fiber optic installers now use a high velocity air blower to blow their wires through the conduit instead of pulling them through, so in theory, you can get motive force from a streamer. |
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Post by rmc on Dec 15, 2013 1:23:42 GMT
Typically on Earth, streamers are used to produce drag for stability. (example: kite tails, tails on improvised munitions, etc). The streamers catch just enough air to produce a little drag and/or add weight to keep the object to which they are attached oriented in the desired position. I've never seen an example of streamers used as a replacement for a sail here on Earth. It seems to me that the shape of streamers would allow the vast majority of usable "solar wind", to pass on by an be very inefficient. You could add more and more streamers to increase the amount of wind they catch, but then this adds size and weight and would rapidly become more a hindrance than an asset. At least to my way of thinking. some fiber optic installers now use a high velocity air blower to blow their wires through the conduit instead of pulling them through, so in theory, you can get motive force from a streamer. And then there are examples from nature: Spider Ballooning |
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Post by the light works on Dec 15, 2013 1:56:45 GMT
some fiber optic installers now use a high velocity air blower to blow their wires through the conduit instead of pulling them through, so in theory, you can get motive force from a streamer. And then there are examples from nature: Spider Ballooningthat will give some people nightmares... |
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Post by User Unavailable on Dec 15, 2013 3:48:33 GMT
Typically on Earth, streamers are used to produce drag for stability. (example: kite tails, tails on improvised munitions, etc). The streamers catch just enough air to produce a little drag and/or add weight to keep the object to which they are attached oriented in the desired position. I've never seen an example of streamers used as a replacement for a sail here on Earth. It seems to me that the shape of streamers would allow the vast majority of usable "solar wind", to pass on by an be very inefficient. You could add more and more streamers to increase the amount of wind they catch, but then this adds size and weight and would rapidly become more a hindrance than an asset. At least to my way of thinking. some fiber optic installers now use a high velocity air blower to blow their wires through the conduit instead of pulling them through, so in theory, you can get motive force from a streamer. not really a viable option for space travel. |
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Post by User Unavailable on Dec 15, 2013 4:13:35 GMT
some fiber optic installers now use a high velocity air blower to blow their wires through the conduit instead of pulling them through, so in theory, you can get motive force from a streamer. And then there are examples from nature: Spider BallooningYep, extremely lightweight spiders and extremely lightweight "streamers". Though there is a different idea as to how this works, well actually, it is the ORIGINAL idea proposed by Darwin, that is now being looked into again, as "streamers" don't explain how spiders can fly on calm days. |
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Post by silverdragon on Dec 15, 2013 10:17:53 GMT
Erm, maybe I can enter a reason why rotation may be good....
If the WHOLE craft rotates, it sort of does the same thing as rotating a bullet.
Timing is required as to the exact moment here, but course correctional bursts on a single motor that rotates around on the ship cut down on weight as well.
Just putting in someone elses two-pennoth worth here... I watched this on some TV show, I think it may have been hosted by a rocket scientist....
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Post by the light works on Dec 15, 2013 15:48:13 GMT
A complete concept came to me this morning:
you build a generic "solar sail assembly" kit. then you capture stray bodies in space, and build up an ice layer seeded with your Multivector Genetic Seed mixture. plant your sail assembly on it, then line them up in pairs with the lighter one ahead of the heavier one. launch each pair on a random vector with the second following just far enough behind the first as to not cast too much shadow on it. configure the sail assembly with a release designed so that as the acceleration from the sail drops to a set point, the sail first tacks slightly to the side, then releases completely and collapses. it might also be designed to impart a slight tumble on the release.
this way, in theory, the second would have slightly better chances of exiting the system without collisions than if each launched alone, and the slight deflections in course result in a wide divergence by the time they got anywhere another star system might be. as for the random vectors - keep in mind that trying to hit a star system with a ballistic projectile from earth would be like trying to throw an egg and hit a car in the Indianapolis 500, from Chicago, using a recording of LAST year's race as your visual guide.
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Post by rmc on Dec 15, 2013 16:22:02 GMT
Cool, the light works. Awesome redundancy concept. I like it. The detachment of the sail could be a problem without your method, it's true. Or, it could turn out that just detaching from the sail, letting it drift along side the craft during the journey, until the craft decelerates (thus separating the two that way) could work too - unless having a sail around nearby causes some issue (like creating a large forward cross section) I like the study on electro-static charge helping the ballooning spiders too. I once wondered if a high altitude balloon could launch over the north pole (near the magnetosphere pole) and use something small, long and stringy and charged enough to enable it get caught up in the light magnetosphere polar wind (a polar jet that Earth actually has). This way, we could say we launched something directly into space, from ground, completely fuel-less. Polar wind as I am meaning is a charged group of particles flowing up and out the funnel-like northern portion of Earth's magnetosphere. Polar wind (Earth): en.wikipedia.org/wiki/Polar_wind |
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Post by the light works on Dec 15, 2013 16:48:18 GMT
Cool, the light works. Awesome redundancy concept. I like it. The detachment of the sail could be a problem without your method, it's true. Or, it could turn out that just detaching from the sail, letting it drift along side the craft during the journey, until the craft decelerates (thus separating the two that way) could work too - unless having a sail around nearby causes some issue (like creating a large forward cross section) I like the study on electro-static charge helping the ballooning spiders too. I once wondered if a high altitude balloon could launch over the north pole (near the magnetosphere pole) and use something small, long and stringy and charged enough to enable it get caught up in the light magnetosphere polar wind (a polar jet that Earth actually has). This way, we could say we launched something directly into space, from ground, completely fuel-less. Polar wind as I am meaning is a charged group of particles flowing up and out the funnel-like northern portion of Earth's magnetosphere. Polar wind (Earth): en.wikipedia.org/wiki/Polar_windI was thinking of just deflecting the two paths from each other slightly, and then releasing the sail so it accelerated slightly ahead of the seed capsule before it lost all solar acceleration. the imparted tumble would be on the seed capsule, to aid dispersion if it passed another star system. addendum: also - with the sail releasing just before thrust vanished, the release could be passive, much like a toy glider passively releasing from the rubber band launcher. |
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Post by srmarti on Dec 28, 2013 5:55:01 GMT
I think something like a Orion propulsion system might actually be able to work for human interstellar travel, but I don't think anyone alive today is likely to live long enough to see one launched. Maybe a robotic exploration mission.... Maybe. Maybe a constant low thrust system of a nuclear powered nature could be built... Is that 50k years Earth time or ship time? Time Dilation at a substantial fraction of light speed decreases the time experienced on board.
I'm thinking we're so far away from doing anything remotely close to a project of this nature, that speculation of the best way to accomplish it is somewhat premature.
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