Through nanotech. J. Storrs Hall (aka JoSH) has some ideas. I have a problem with this one, though:
So you have this balloon and it floats up there twenty miles. They all have a little GPS and receiver so they can turn themselves. That’s all there is to it. What can you do with a machine like this? The machine is essentially a programmable greenhouse gas. If you set the mirrors facing the sun, it reflects all the sunlight back. If you set them sideways, it allows the sunlight to come through, and similarly for the longwave radiation coming from the back side of the earth at night.
He seems to be implying that GPS can be used to determine attitude. It can’t. It only provides velocity and position. Now it may want to know that information for other purposes, but there will have to be some other means of attitude knowledge. It seems to me the simplest way would be to just measure the sunlight hitting the mirror (which would actually be a solar cell). As you adjust your attitude, the power available will grow or shrink, and it can use the rate to control the angle. As for how to physically control the attitude, I would guess that little reaction wheels would do the job.
Of course, many of the warm mongers hate technical solutions like this, because they don’t require us to piously tighten up our hair shirts, and they don’t allow for sufficient control of the global economy.
The link is broken so I can’t read the article.
I started a comment about putting two receivers on the balloon and allowing the separation of the two to determine attitude, then I reread the first sentence and saw that nanotech is being discussed.
Probably not enough separation to do the job.
As I mentioned at Next Big Future, no nation would trust any other nation with this tool. If you could focus sunlight you could burn cities, or deny their farmland the sun. And that’s assuming no one “hacks” the controls for terrorist ends.
Rand, have you read about Hall’s Space Pier concept? It seems pretty neat, and more feasible than the space elevator. Is there any reason it couldn’t work once the materials science allows the construction of the 100 km tall towers?
Link is fixed now.
With multiple antennas and receivers, GPS can provide attitude information.
For example, see the Stanford University work at:
waas.stanford.edu/~wwu/papers/gps/PDF/att_for_aircraft_rch1998.pdf
I’ve also found references to single antenna implementations; just Google GPS Attitude information.
With multiple antennas and receivers, GPS can theoretically provide attitude information.
You need to ask a man called Javad Ashjaee about the practicalities. As it turns out, sufficient spacing between the antennas is impractical because of second, third, and fourth-order variations in the GPS signal. The math works. The physical realizations don’t.
However, in a multireceiver net, the individual devices should be able to determine the direction to one another using rather simple DF techniques, and they should be both fairly far apart and numerous enough to apply statistical techniques. If they can also exchange position information, and preferably the phase relationships of the GPS signal(s), attitude data at some reasonable level of accuracy should be possible. I don’t know if anyone has actually worked the math out.
Regards,
Ric
Could you set up the floaters so that they have a default weathervane behavior, and then, when you detect that the floater is drifting with the wind, you could infer the attitude?
If the physical realizations don’t work, how does one explain the Brad Parkinson paper (1993) quote:
“Real time attitude capability has been demonstrated with an accuracy better than 0.1 deg at an output rate of 10 Hz.”
Their test bed was a King Air.
Gary is right on this one, GPS can be used for attitude determination. However, it is cheaper now to use a star sensor so it has fallen out of favor in the small sat world.
I work with JP Aerospace. We send balloons up to 100k feet routinely. The GPS receivers on our balloons give attitude information all the way up. I believe it’s possible to get altitude information almost to the orbit of the GPS satellites at around 20k km up.
I work with JP Aerospace. We send balloons up to 100k feet routinely. The GPS receivers on our balloons give attitude information all the way up.
Obviously, if you have differential receivers hundreds of meters apart on a structure that large, you can detect attitude. My point was that it’s a much different problem on a tiny balloon…
http://www.trimble.com/ms860.shtml
Above is one commercially available GPS position and HEADING sensor. I have seen them available for commercial and recreational boats.
Trimble had a receiver years ago that could do 3 D attitude, the TANS VECTOR receiver. Some friends of mine were using one in a Grob Egret for atmospheric research. You don’t need hundreds of meters separation on the antennae.
A meter or so is OK depending on your accuracy requirement. Anyway on a balloon I’d just use a solid state magnetometer. These are readily available at low cost. I have one on my bench with an SPI buss interface and it fits in a 0.5″ on a side cube.
#7 Bob: Think about what a balloon does. There’s no relative airflow so no weathervane effect.
Turning the balloon is another issue. One reaction wheel for heading orientation will do. Suitably weighted the balloon will orient vertically so one small servo will then do for vertical mirror orientation.
Now lets talk about balloon materials that will take the UV exposure long term.
Anybody want to guess what NASA could make these cost?
Rand, the GPS receivers we use work just fine on small balloons. I think the biggest restriction is a speed restriction. They cut out on the boost phase of a sounding rocket, for example.
I don’t know about balloons but I can get evelation information from my hand held Trimble GPS unit when I am surveying. Not very accurate though.
Hmmm.
In an amazing world of idiotic ideas this frankly takes the proverbial pancake.
Seriously here. 10 million tons of highly advanced nanotechnology to counter a problem that doesn’t exist? So let’s say making these highly complex nanotech devices costs about $1000 a pound, which isn’t necessarily an absurd figure. This nonsense would end up costing a measly $20 Trillion Dollars.
Oh and I’m sure the Chinese would be overjoyed to have someone else controlling the sunlight that falls on their territory. Or anybody else for that matter.
…
IMO I’m rather sick of various ridiculous schemes that somehow always end up relying upon someone else making it work with “nano”. It seems almost like a rehash of every bad ST:TNG episode where the conclusion requires the main dish to emit some silly new particle just discovered in the last 10 minutes. How will it work? Nano! Why would anyone want to do this? ‘Cause with nanotech you get eggroll!
I can only repeat the fine English phrase for just such a situation:
Bollocks!
So let’s say making these highly complex nanotech devices costs about $1000 a pound, which isn’t necessarily an absurd figure. This nonsense would end up costing a measly $20 Trillion Dollars.
Actually, it’s an utterly absurd, even ludicrous figure, if for no other reason that if it were really that much, it would never happen. If molecular assemblers work, their products will be (almost literally) dirt cheap.
Hmmm.
@ Rand
“Actually, it’s an utterly absurd, even ludicrous figure, if for no other reason that if it were really that much, it would never happen. If molecular assemblers work, their products will be (almost literally) dirt cheap.”
1. Right. And nobody will charge money for the use of such assemblers.
2. And nobody will charge money for the power necessary to run these assemblers.
3. And nobody will mind producing enough of these assemblers to manage 10 million tons of materials.
4. And nobody will have any problem in handing over 10 million tons of valuable materials to make these things.
5. Everything is free.
C’mon Rand. Unless you’re trying to posit a Star Trek Federation style future everything is going to have to cost -something- to make, manage, etc. What about the people who actually design the things? Don’t they get paid? What about -insurance-? What about healthcare benefits for the people working in the manufacturing facility? What about the support crews? What about the people manning the phones lines when frightened soccer moms start screaming because the sky went dark? What about the scientists on staff, and on call, to answer questions?
Or is this a “Government going to do it so it’s all free” sort of schtick?
The idea that molecular manufacturing will result in free stuff is a nice idea as a concept. But I really don’t think it has any relevance or value in a serious debate. Unless you’re positing the complete annihilation of anything resembling an economy. And if we’re capable of that then why would we be jerking ourselves around making billions of tiny balloons?
So are we positing in the near future or the ridiculous future? If it’s in the near future then there are limits to what can be done and part of those limits is that there is going to have to be an associated cost to these things. If it’s the ridiculous future then I say screw global warming and bring on the sex-bots, the holo-tv, grav-ball and the super-sized Orgasmatron!
The idea that molecular manufacturing will result in free stuff is a nice idea as a concept.
[Rereading my comment, over and over, till my eyes are crossed…]
Nope. Can’t see anywhere where I said it would be “free.” Nice plump straw man, though. Did you use all the straw you have?
In any event, it will be a hell of a lot closer to “free” than it will to a thousand dollars a pound.
Hmmm.
@ Rand
“Nope. Can’t see anywhere where I said it would be “free.” Nice plump straw man, though. Did you use all the straw you have?”
I disagree completely. It is not a strawman at all. It’s called -sarcasm-.
Because even if it were free who would you sell/give it to? Who on Earth would want 10,000,000 tons of crap floating in the air that may or may not stay there. And that may or may not respond properly to commands. And that may or may not completely to partially shut off the Sun?
So who would buy it? And for how much? How much does the physical plant cost? How much does the energy to run it cost? How much is the payroll? How much is the inbound shipping? How much is the outbound? You’re talking about building 10,000,000 tons of crap and using valuable resources to do it.
So who is going to buy it? A private company? I hardly think so. So all that’s left are governments since they’re the only ones that could handle the potential liability.
And I challenge you, –challenge–, you to find anything that requires 10,000,000 tons of raw materials that the government can do, or worse -contract-, that could possibly defined as “dirt cheap”.