63 Replies. 4 pages. Viewing page 1.
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| 63. |
Re: New NASA vehicles |
Aug 3, 2005, 13:48 |
Creston |
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No, 53k miles total, or ~26.5k miles plus counterweight. 106k miles would be twice as much as you need.
The reason is that you need the center of mass to be in geostationary orbit, which is approx. 26.5k miles up from the equator
Oh, the 53K includes the counterbalance, okay that makes sense. I couldn't figure out what was so special about 53K miles above the earth, but I understand it being in geosynchronous.
Cheers 
Yes, but it will happen eventually if we get into space. That's where the most accessible minerals are. It's not exactly cost effective at current prices (opportunity cost is a bitch), but asteroids are awfully useful and "common" things in space anyway.
Well, mining one is different from capturing one, in my opinion. Imagine the thrust you need to get a frigging ASTEROID into perfect orbit around the earth.
Creston
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| 62. |
Re: New NASA vehicles |
Aug 3, 2005, 13:05 |
Zathrus |
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I'd hate to see them build something 53000 miles long, and then try to get it upright into space
The most common design is similar to that of suspension bridges -- you haul a thin spool of cable into orbit and then extend it in both directions. Once you've secured the lead cable you can then start adding additional cables to strengthen it until you reach the desired load capacity.
Why does it need to be 53000 miles to counterbalance with another tube (heh, 106000 miles of the stuff)
No, 53k miles total, or ~26.5k miles plus counterweight. 106k miles would be twice as much as you need.
The reason is that you need the center of mass to be in geostationary orbit, which is approx. 26.5k miles up from the equator (yes, you must build this on the equator, just as all geostationary sats are currently above the equator; that has certain weather advantages anyway). If you only built a tether downwards then the center of mass would be well below geostationary orbit and the space anchor would not "keep up" with the ground anchor. So you extend a second cable in the opposite direction. If you have a large mass then you don't need so much "extra" cable.
And yeah, I'm sure that asteroid capturing is something we'd just go and do. That's going to require one mighty massive operation.
Yes, but it will happen eventually if we get into space. That's where the most accessible minerals are. It's not exactly cost effective at current prices (opportunity cost is a bitch), but asteroids are awfully useful and "common" things in space anyway.
I didn't realise the thing was that wide, but even so, I'm sure it would get pretty damaged if a big plane slams into it. Maybe it won't shear off, but what happens if the cable gets damaged at 20000+ feet? We build a huge ladder to get to it and fix it?
The numbers I've seen have it being very tiny (<1 cm) at the earth base and very wide (1-10 km) at the space base. If you really want to see the math it's on the Wikipedia page. Oh and it's flat/ribbon like, not circular like a cable.
So it's likely to be somewhere in the 3-10m range for any airplanes. And it has a tensile strength that's vastly higher than any plane's while also being under load (but with enough extra capacity to deal with things like this). It would literally cut the plane into shreds.
As for repair, it has to be repaired constantly to deal with meteorite strikes, micrometorites, and the like. It's among the unsolved problems, but it's one that must be solved in order to be feasible at all.
If you want to look at total failure scenarios, I refer you again to the Wikipedia page.
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| 61. |
Re: New NASA vehicles |
Aug 3, 2005, 11:31 |
Creston |
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It may not have weight, but it still has mass. And to move that kind of mass any distance at any speed is going to require a lot of thrust.
Yeah yeah, I'm not fucking scientist, give me a break 
I said from the start it would need a ton of maneuvering thrusters, and I was right. WHY it needs a ton of them, I don't care.
Agreed... realize that it doesn't have to be continuous though. You can splice cables together once they're long enough.
Well, obviously. I'd hate to see them build something 53000 miles long, and then try to get it upright into space. Might be fun to build something that actually circles the earth though.
Oh, and you only need 53k miles if you want the counterbalance to be another ribbon of carbon nanotube. A lot of alternate plans call for a short counterbalance arm tethered to a captured asteroid or something... obviously easier to do once you have the first space elevator/tether/hook up and running. You probably want one full length tether anyway for the launch capabilities.
That doesn't make any sense to me. Why does it need to be 53000 miles to counterbalance with another tube (heh, 106000 miles of the stuff)... Why can't it be shorter? I figured we'd want it that long to escape more of the gravitational pull once we finally have junk in orbit up there.
And yeah, I'm sure that asteroid capturing is something we'd just go and do. That's going to require one mighty massive operation.
Yeah, I'd feel sorry for the plane.
What do you think will happen if you run a plane into a ribbon 10 meters wide that has a tensile strength 100x that of high-carbon steel? And is under load. Hot knife through butter anyone?
I didn't realise the thing was that wide, but even so, I'm sure it would get pretty damaged if a big plane slams into it. Maybe it won't shear off, but what happens if the cable gets damaged at 20000+ feet? We build a huge ladder to get to it and fix it?
Creston
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| 60. |
Re: New NASA vehicles |
Aug 3, 2005, 09:38 |
Zathrus |
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Obviously in space it has virtually no weight
<weeps>
It may not have weight, but it still has mass. And to move that kind of mass any distance at any speed is going to require a lot of thrust.
t's going to be a seriously long time before we ever build 53000 miles of the stuff
Agreed... realize that it doesn't have to be continuous though. You can splice cables together once they're long enough. We're just nowhere close to "long enough" yet, and even the research-only manufacturing methods are far too short. But things are moving pretty quickly in that arena... and carbon nanotubes are fantastically useful stuff, so there's a lot of private research money being put into them. I wouldn't be surprised if we have that issue licked in 20 years (to be fair, I also wouldn't be surprised if it's 50+ years... things like this and fusion have the annoying tendancy to be just out of reach).
Oh, and you only need 53k miles if you want the counterbalance to be another ribbon of carbon nanotube. A lot of alternate plans call for a short counterbalance arm tethered to a captured asteroid or something... obviously easier to do once you have the first space elevator/tether/hook up and running. You probably want one full length tether anyway for the launch capabilities.
I'd also be worried about idiot pilots who'll fly their plane into the thing.
Yeah, I'd feel sorry for the plane.
What do you think will happen if you run a plane into a ribbon 10 meters wide that has a tensile strength 100x that of high-carbon steel? And is under load. Hot knife through butter anyone?
Oh, and Apollo 13 was a great movie and testimony to the space program.
This comment was edited on Aug 3, 09:39. |
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| 59. |
Re: New NASA vehicles |
Aug 3, 2005, 07:36 |
Jim |
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| 58. |
Re: New NASA vehicles |
Aug 3, 2005, 05:16 |
Tango |
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I'd put AA batteries in 10 and 5 mile circles around the thing, and any plane that enters that 10 mile no fly zone gets shot down, no questions asked. That is precisely what'd happen, except it'd be more likely to be a 150 mile exclusion zone.
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| 57. |
Re: New NASA vehicles |
Aug 3, 2005, 00:16 |
Creston |
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You spin around 53,000 miles of carbon nanotube
Oh is that all? Let me start spinning, I have a few miles of the stuff in my balcony closet anyways...
The concept is awesome, but it's going to be a seriously long time before we ever build 53000 miles of the stuff. I'm thinking true nanotech will (have to) come around before that.
I'd also be worried about idiot pilots who'll fly their plane into the thing. Think that will never happen? We have idiots who fly their planes into fucking mountains because they weren't paying attention, they fly them into power cables, into radio towers etc.
If the plane then snaps the cable, what then? "Oh, oops" from the pilot, and goodbye 5 trillion dollar investment?
I'd put AA batteries in 10 and 5 mile circles around the thing, and any plane that enters that 10 mile no fly zone gets shot down, no questions asked.
I stand corrected on the benefits of the moon missions, I wasn't aware that most of those items had somehow been connected to that. Pretty cool if you think about it. Now I want to watch Apollo 13 again.
"Why can't we use the scrubbers from the LEM?"
"Well, the scrubbers from the LEM are round, and the ones on the command module are square."
"Tell me this isn't a government operation..."
Heh, good old Ed Harris
And hey, it's not like I'm AGAINST the space program or anything, don't want to give off that idea. Put money into it and let's go. Preferably next year. Put a bunch of cameras onboard that thing, and let me watch 24/7 on my "Mars Mission Sunday Live" package or something! I'm ready baby, let's go!
Creston
This comment was edited on Aug 3, 00:22. |
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| 56. |
Re: New NASA vehicles |
Aug 3, 2005, 00:09 |
Creston |
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As far as moving 100 tons in space, well you can move 100 tons in space with your finger tips, if you can fine a platform to stand on. Good Ole Newtonian physics.
They might have to break the cargo down into smaller segments, but if they wanted to, I do not see why they could not dock 100 tons to the ISS
Honig,
I was talking about the size of the capsule, not the weight. Obviously in space it has virtually no weight (minor gravitic pulls from earth / sun whatever not taken into account). But in order to dock to the space station, it would require some fine maneuvering, and on a container that size, that would mean a LOT of maneuvering thrusters.
Creston
This comment was edited on Aug 3, 00:17. |
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| 55. |
Re: New NASA vehicles |
Aug 2, 2005, 22:33 |
Zathrus |
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Ever read the Mars trillogy by Kim Stanley Robinson?
Yes. Note that Robinson admitted that he got the physics wrong on what happens if you blow the cable.
Edit: Still a great series of books that combines technology, ecology, politics, interpersonal relationships, and a bunch of other stuff. Red Mars is by far the best of the three.
This comment was edited on Aug 2, 22:33. |
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| 54. |
Re: New NASA vehicles |
Aug 2, 2005, 21:52 |
Honig |
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Space elevator: most obvious terrorist target... EVAR!!!11One
Ever read the Mars trillogy by Kim Stanley Robinson?
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| 53. |
Re: Dad 'n Me |
Aug 2, 2005, 20:58 |
MeatForce |
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hey isn't this the new game "Bully" from cRockStar?
I shudder to think what the Hot Coffee mod for a game called Dad 'n Me would entail
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I actually get paid for this.. |
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I'm not even angry. I'm being so sincere right now, even though you broke my heart and killed me. |
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| 52. |
Dad 'n Me |
Aug 2, 2005, 20:43 |
FourPak |
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hey isn't this the new game "Bully" from cRockStar?
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| 51. |
Re: Ahhhhhhhhhhh! |
Aug 2, 2005, 20:34 |
FourPak |
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Dr. Toothy == Dr. Grifter
Grifter:
1. Money made dishonestly, as in a swindle.
2. A swindle or confidence game.
n : a person who swindles you by means of deception or fraud [syn: swindler, chiseller, chiseler, gouger, scammer, sharper, sharpie, sharpy]
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| 50. |
Re: New NASA vehicles |
Aug 2, 2005, 20:22 |
Zathrus |
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What would be the point (read: looking for a solution) then if we couldn't travel at uber speeds since it would still require vast amounts of fuel to travel to x planet(s).
Actually it would take anywhere from near zero fuel to very little fuel to get anywhere you wanted in the solar system.
The vast majority of fuel expenditure is to get out of the gravity well of Earth. If you took an equivalent amount of fuel in geostationary orbit you could get anywhere you wanted in the solar system... quickly (well, relatively quickly).
And you don't even need to spend any fuel if you have a space elevator. If you design for it you can use the counterbalance mass as a slingshot to get you most places in the solar system (slowly) without using any fuel at all.
I can't even imagine the size of the pump needed to also run a tube or several for that matter, all the way up the elevator.
Uh... it's not that kind of elevator. You spin around 53,000 miles of carbon nanotube (the only stuff we know of that could take the stresses). Spin it out from a point in geostationary orbit to a location on the equator (the other half goes out the other way as balance). Then you run "crawlers" up and down the ribbon (which is up to several meters in diameter) to transport goods up and down. Most of this has been thought out and is probably on the aforementioned Wikipedia page. It costs energy to go up, but you can recoup most of that energy on anything going down. You can also use the geostationary platform for energy gathering from the Sun.
The entire point of this is to get stuff into orbit cheaply. You have a one time cost in the trillions of dollars, sure, but it costs nearly nothing to move tons of goods up or down the elevator. Right now we spend >$10,000 per pound to get into LEO, much less geostationary orbit.
As for terrorist target -- go ahead. First you'll have to get past the layered defenses around the cable base station, then somehow sever the carbon nanotubes. And the end effect would be that the rigging above would fly off into space -- it would not cause some massive disaster on Earth as some believe. If you managed to somehow cut the counterbalance off (good bloody luck) then the geostationary piece would have safeguards that would unmoor the cable from the space end and 90% of the cable would burn up in reentry -- only the first few miles of cable near the ground wouldn't do so.
It's going to be a long time before we can build anything like this though -- the carbon nanotubes we're able to build right now don't have the tensile strength needed and we can only manufacture them in lenghts of a few micrometers. There are also other issues to deal with -- we're unsure of the effect a space tether would have on weather systems, what the effect of lightning on the cable would be (remember, it has to carry power and signalling as well; and the cable is going to be one hell of a lightning rod), exactly how you'd manage the mooring, and so forth. Nothing that's a show stopper, but well beyond what we're capable of right now. And, as I mentioned, it will cost trillions. Maybe more. But how much was the intercontinental railroad worth in the US? Or the trade routes to the New World or the East Indies? We're talking about this kind of potential.
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| 49. |
Re: New NASA vehicles |
Aug 2, 2005, 20:00 |
Enahs |
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Only if it's eco-friendly foam. Some sort of ozone-destroying foam would prob'ly be ok
Yeah.
That is what pisses me off so much about all this bad publicity NASA is getting.
I think we should pass a law that says every time a new reporter says something about it they should be required to say “only because they can not use the foam the original designers of the space shuttle called for…because they where fing geniuses and we are to much of pussies to tell the eco-nauts to f-off so we can stop wasting money and lives”.
“I find the most erotic part of the female anatomy is the boobies.” -Zap |
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I am free of all prejudice. I hate everyone equally.
- W. C. Fields |
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| 48. |
Re: New NASA vehicles |
Aug 2, 2005, 19:48 |
Gen. Hospital |
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Only if it's eco-friendly foam. Some sort of ozone-destroying foam would prob'ly be ok
EDIT: Spelling. Could I blame my new keyboard?
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GW: Vergil Gregorius, lvl 9 12 13 Warrior/Necromancer
This comment was edited on Aug 2, 19:51. |
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| 47. |
Re: New NASA vehicles |
Aug 2, 2005, 19:45 |
Enahs |
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The question is 'could it be done', and I think yes.
If we can and do, do it…let’s just freakin’ hope the design does not call for any kind of foam used in anyway.
“I find the most erotic part of the female anatomy is the boobies.” -Zap |
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I am free of all prejudice. I hate everyone equally.
- W. C. Fields |
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| 46. |
Re: New NASA vehicles |
Aug 2, 2005, 19:42 |
Gen. Hospital |
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But ehh…I think the whole space elevator things seems kinda dumb.
Right... The question is 'could it be done', and I think yes. Such a thing would be so useful, I think it's pretty much inevitable. The timeframe... well... I don't think there's any reason to be holding ones breath in anticipation for the project to start.
___________________________________________
GW: Vergil Gregorius, lvl 9 12 13 Warrior/Necromancer |
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| 45. |
Re: New NASA vehicles |
Aug 2, 2005, 19:36 |
Enahs |
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In addition, if you got stuff going down, say minerals mined from asteroids, you get lift for free.
Actually, in theory you could use a space elevator as a giant electric generator as well.
Expand energy to get up, but when you load the container with your mined ore from asteroids or other planets. Simply let gravity pull it back down (with controlled breaking of course) you could easily use that to turn a generator ala water dam.
But ehh…I think the whole space elevator things seems kinda dumb.
The answer is simple, Nuclear Fusion !
“I find the most erotic part of the female anatomy is the boobies.” -Zap |
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I am free of all prejudice. I hate everyone equally.
- W. C. Fields |
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| 44. |
Re: New NASA vehicles |
Aug 2, 2005, 19:32 |
xXBatmanXx |
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Yeah, I can see us mining a lot of asteroids in short order.
There is zero need for a space elevator.
I was getting there.....just in a round-a-bout way.
My wants: GTA DC (politicians) and GTA FL (crazy nut job lawyers) |
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In this present crisis, government is not the solution to our problem; government is the problem. / Few men have virtue enough to withstand the highest bidder.
Playing: RL |
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63 Replies. 4 pages. Viewing page 1.
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