Yup I'm back, and while I dont have an idea to share about getting to space this time, I want to hear ideas from you people. I'm sure many of you have heard of the X-prize (www.xprize.com) but whats your ideas on how to get to orbit? Nobody has to reply but what the heck this forum has been a little dead latly and some ideas could be intersting to hear.
Nanotubes woven into a series of tethers attached to a geostationary orbiting platform. "Going up...ladies lingerie".
There are a few things that bother me about the 'elevator' concept: 1) air friction. Since air is not still, and has an overall nonzero motion over any air column, you have this enormous atmospheric drag on the tether, integrated all the way from ionosphere down to the surface. I don't know if anybody actually tried to calculate the drag force resulting from air currents -- is it not going to be a huge show-stopper, requiring constant boosts to the geostationary 'terminal', and making the surface-end swing around wildly with changing weather patterns (or if it's attached to the surface, wouldn't the tether end up vibrating like a string)? 2) precipitation. Starting a couple of miles above ground, there are likely to be real problems with ice build-up. 3) expensive maintenance. Once the tether begins to wear out, there's no way to repair it; you must replace the entire length of it. And then you face the problem of actually taking the tether down without having it crash on the surrounding structures (after all, the orbital end of it is moving a heck of a lot faster than the Earth's surface!) Of course, you also must have mechanisms that would constantly monitor the tether's health over its entire length, and remove depositing minerals from its surface. 4) Simple Newtonian action-reaction. You start with a slow-moving object on the surface. But, as it rises up the tether, its orbital speed increases. This creates a backward tug on the tether (not to mention a downward tug by the object moving up). Would this not mean that the orbital end of the tether would need constant boosting? If so, just how much less energy would you need to get into orbit? Would the energy savings be worth the expense of the tether? If you know of a web-site that answers my questions, I'd appreciate a pointer... ------------------ I am; therefore I think.
Yeah thats about the same points I was going to say boris (except the newton part)bu any other ideas? Come on someone has to have them I dont care how crazy they are. Lets here 'em!!
Good points on the tether, Boris. I haven't done the maths to calculate the effect of atmospheric drag. http://www.tethers.com has some stuff though. In general terms, your objections notwithstanding, I still think it's an interesting idea. This is because *if* it's feasible, it's an awfully cheap and easy way to get into space. It's almost certain that a constant reservoir of power would be required at the orbital end. The deal here is, that - by using solar power and machinery, it's not expensive to do this compared to the cost saved hauling ourselves out of the gravity well by conventional means time and time again. I think the key to success is the strength/weoght ratio of the nanotubes (which currently can only be grown to a few hundred microns, and we need over a hundred kilometres for a tether). If enough safety margin can be built in, and the energy unit topside can be built to be reliable and durable, the idea might just be economically worthwhile. But, really, this is mainly gut feel. There are so many parameters, and so many as-yet-unknowns to figure out.
SolarGuy: Your nick suggests that you're "into" this solar power stuff, but I think you need to be more into it than your post suggests. Have you run the numbers on your proposal? Do you know how large a solar sail would be needed to be to lift something, and the sail itself, into orbit? I suspect not (but I could be wrong). As far as I know, what you suggest is impossible.
Somewhat like the way that Solarguy proposed to use solar "sails" attached to a ship to go into space, what if we could make a terminal, like a pyramid in construct with giant solar panals along the sides, on the inside of this solar pyramid, have generators hooked up to amplify the amount of energy produced, then that energy is conducted into the fuel cells of a ship, a shuttle if you will, that will make thrust of it's own and use a rail to steer it to the next terminal
Didn't NASA do a teather experiment to generate power on the space shuttle in the recent past? Could the teather to orbit also generate power on the side? Or, since the teather won't be moving relative to the earth's magnetic field, will the power generation idea not work in this case? If it did work, could the power generated somehow be used to help solve some of the teather's technical problems? Or, the power could be sold, to help defray the costs of operating the teather.
Interesting idea. The 'to orbit' tether would be geosynchronous, and thus it would not move through the Earth's magnetic field. As a result, no current would be induced in it that way. However, there is plasma in space. I wonder what would happen if we took a conductor and stretched it from the earth's surface out to space. I wonder how much current we'd get along the tether (we'd certainly get *some*, that's for sure)... ------------------ I am; therefore I think.
