Aerobraking better than "Trust in Thrust"
on
The Art of Aerobraking
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· Score: 2, Interesting
Aerobraking is an elegant solution, making possible missions that aren't otherwise possible. Applying the lessons learned from Mars Global Surveyor, just make sure your structural design is sound, and go about your aerobraking conservatively and patiently.
In other words, you do the statistics and you just dip far enough into the atmosphere that there is only a.00000001% chance (or whatever level of risk you're willing to assume) of overheating or overstressing the spacecraft on any given pass.
Maybe someday thrust will be so cheap we don't need to spend weeks in an aerobraking phase, but until then, I hope we get very good at it.
The average American living below the "poverty line" has access to running water, penecillin, and free entertainment broadcast over the television networks. The wealthiest king of 500 years ago had none of these things. Poverty still exists in America only in a relative sense. In an absolute sense, it is as defeated as smallpox.
The average taxpayer has only 2% of the understanding needed to decide which lines of research are most promising and deserving of funding. Thank goodness the taxpayer is not in direct control of this!
Being near the equator is an asset when launching into low-inclination orbits, and a liability when launching into high-inclination orbits. Being near a pole is an asset when launching into polar orbits, but makes it nearly impossible to launch into low-inclination orbits.
The Cisco 675 I use for DSL access was acting sluggish/nearly dead this morning, just like it did a few weeks ago when Code Red was going around. Are there any reports of Nimda causing this kind of thing?
Ender Ryan, I urge you to check out all the following URLs. Reasonaby-priced CPU upgrades are available for just about every Mac and Mac clone ever made, including the iMac. And the true plug-and-play nature of the Mac makes these upgrades a much easier proposition than upgrading a PC.
You can often turn a single-processor mac into a multi-processor Mac!
RAM and HD upgrades are of course, also cheap and easy. Adding or expanding USB, FireWire, and ethernet ports is cheap and easy.
And one underappreciated thing about the Mac is the teriffic support for multiple monitors when you add one or more video cards to supplement the built-in video. (And many Mac flight sims support multiple monitors, for simultaneous front and side views! : )
Here is a good image of the entities Arthur C. Clarke has termed "banyan trees."
Note how there is a dendritic, tree-like structure radiating outward from a central "trunk." I know crystals can sometimes grow with a dendritic structure, but consider the scale of the image: about 5 meters per pixel. These are huge structures.
Also note that they appear to rise above the surface to a significant height. Sunlight is coming from the bottom of this image; the ground is bright on that side of the objects, and in shadow on the other side.
Bill Weller took four Mars Pathfinder images and created an animated, 3-D stereogram of something popping out from behind a rock. (Hope you are good at crossing your eyes to resolve those "Magic-eye"-type images.)
He nicknamed the organism the "Zolax." (Scroll two-thirds of the way down the page to see it.) If it resembles any earth organism, I would say the tarantula -- although it seems to have a half-dozen or so "tentacles," rather than articulated legs. If you look closely at the lower-left corner of the image, you'll even see one of the tentacles in contact with the ground. The point where it's attached to the body is hidden behind the rock, and it's casting a shadow! If this is a hoax, the hoaxer showed admirable attention to detail.
Disclaimer: the other purported anomalies on this web page are pretty dubious. (Don't you hate when some wacko points to a JPEG artifact and says "look, an artificial structure!" or "look, an organism!") I wish they weren't on the same page as the Zolax, because they hurt its credibility. Nevertheless, the Zolax looks like the real deal. It appears in both the left and right cameras simultaneously, so it can't be an image-processing artifact. It could be a hoax, but it would take a lot of effort to fake a stereo image like this.
It would be nice if we knew the time interval between the two frames -- then we'd have an idea of how fast this critter moves.
Not to difficult to believe that all the still-unoxidized iron on the planet serves as the sink for the oxygen these critters produce -- assuming they produce oxygen at all.
Is this simple a clock speed multiple? For example, the PowerPC G4 currently tops out at 867 MHz. If it was made with this new gallium technique, would it then be able to be clocked up to 30 GHz?
Most of the stuff I've read about GaAs chips indicates they're used in RF signal processing. If Motorola makes them inexpensive, will they also show up as CPUs in desktops, laptops, and PDAs?
In order for the light-emitting property to provide cooling to the processor, GaAs would have to be able to convert heat energy directly into light energy. Sorry, that's not how it works.
I believe GaAs works just like light-emitting diodes; LEDs don't get hot because electrical energy is converted directly to light, but at the same time there is no "cooling" of the LED taking place either. I don't know of anything that can convert heat directly into light. (Unless you count blackbody radiation given off at optical wavelenghts by very hot objects -- let's hope your CPU never gets that hot!)
Rich benefactors could really make a difference
on
Mice Headed for Mars?
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· Score: 1
According to Robert Zubrin you can set up a permanent base on Mars for $12 billion. That's what, only about 20% of Bill Gates' wealth? He could do this singlehandedly, and still have plenty of bucks left over for philanthropy.
(Although the act of giving our species a foothold on another planet would probably in itself be judged by future historians as the greatest act of philanthropy of all time.)
The only thing stopping him is a lack of vision. I'd be willing to forgive the lame software he foists upon me, if he turned us into a spacefaring species!
(Before people tell me his wealth is all on paper, and he wouldn't be worth nearly that much if he tried to sell his stock all at once, I know that. To build a Mars colony, he woulnd't have to sell his stock all at once. He would sell it a little bit at a time, over a 10 - 15 year period.)
Then how about defining the kg as "the rest mass of 2.1421235313 x 10^29 deterium atoms" (or whatever). That gets around your concern about whether to use the bound or unbound proton mass.
Point is, it can be defined in this manner, and it's not a circular definition.
This new apparatus is a very elaborate, and I'm sure very accurate, way to weigh their reference mass -- but the reference mass is still right at the heart of it. So how is this a fundamental change in the definition of the kg?
Not enough people have broadband yet. That's why the radio stations aren't seeing the increase in listenership they were expecting. They are giving up on their streams too soon. Come back in 5, 3, maybe 2 years and the economics of this will be completely different. Problem is, this has left them with a bad taste in their mouths and they may be disinclined to try streaming again even though the economics would support it.
AFTRA members deserve a somewhat larger fee when their work is streamed -- but not so much larger that it makes streaming unviable. They are just shooting themselves in the foot in that case. Same goes for the RIAA's streaming fee. What do you want to bet those fees were negotiate near the peak of the dot com bubble? Now that the bubble has burst, they should certainly be renegotiated. Better yet, the fee structure should be made a dynamic function of online listenership, so that streaming remains viable whether the online listenership grows as expected or not.
If this was the real deal, why would they sit on it for three years? That's a lot of revenues lost while they take their good old time commercializing the technology.
How do "holes" move? When a hole moves, is it not actually an electron moving from one place to another -- leaving a new hole in the place where it left, and filling the hole in the place where it ends up?
If so, I don't see the difference between electrons carrying current and holes carrying current.
I can't believe the DOJ didn't use the bootloader issue in the trial. I agree with the article that it's a far worse anticompetitive practice than bundling a browser.
By the way, my Mac is quad-booting LinuxPPC, Darwin, OS X, and OS 9. Setting this up was easy!
By breaking the patent on AIDS drugs, Brazil is definately keeping their long-term interests in mind
Yes, there's no question that Brazil benefits from this move. But the human race as a whole suffers. It's a net loss to humanity.
Taking the argument to extremes often helps. What if there was a drug so insanely resource-intensive to develop that the pharmaceutical firm could only hope it recover its costs by charging $1 million per daily dose. Only Billy Gates and a handfull of others could afford to take this drug. And they are the only ones who should take it. 20 years later the patent will expire and you and I will be able to benefit from it too. But if the patent hadn't been honored, nobody, at any time, would ever benefit from it because it would have never been developed!
what good is R&D and new drugs and technologies if only x% of the world can take advantage of developments supposedly in the name of 'humanity'?
Drugs aren't developed in the name of humanity, they're developed for the benefit of stockholders. The fact that they also benefit humanity is fortuitous gravy. You may think that is a cold system, but it is a system that has worked exceedingly well. It is a system that has discovered hundreds of miraculous treatments.
In 20 years the patent will expire and then the third world country can start making the drug.
When patents are honored, we have the first world nations getting the benefit of the drug for 20 years, followed by everyone getting the benefit of the drug.
When patents are not honored, we have nobody getting the benefit of the drug because it's never developed in the first place.
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Aerobraking is an elegant solution, making possible missions that aren't otherwise possible. Applying the lessons learned from Mars Global Surveyor, just make sure your structural design is sound, and go about your aerobraking conservatively and patiently.
.00000001% chance (or whatever level of risk you're willing to assume) of overheating or overstressing the spacecraft on any given pass.
In other words, you do the statistics and you just dip far enough into the atmosphere that there is only a
Maybe someday thrust will be so cheap we don't need to spend weeks in an aerobraking phase, but until then, I hope we get very good at it.
The average American living below the "poverty line" has access to running water, penecillin, and free entertainment broadcast over the television networks. The wealthiest king of 500 years ago had none of these things. Poverty still exists in America only in a relative sense. In an absolute sense, it is as defeated as smallpox.
The average taxpayer has only 2% of the understanding needed to decide which lines of research are most promising and deserving of funding. Thank goodness the taxpayer is not in direct control of this!
Being near the equator is an asset when launching into low-inclination orbits, and a liability when launching into high-inclination orbits. Being near a pole is an asset when launching into polar orbits, but makes it nearly impossible to launch into low-inclination orbits.
The Cisco 675 I use for DSL access was acting sluggish/nearly dead this morning, just like it did a few weeks ago when Code Red was going around. Are there any reports of Nimda causing this kind of thing?
You can often turn a single-processor mac into a multi-processor Mac!
RAM and HD upgrades are of course, also cheap and easy. Adding or expanding USB, FireWire, and ethernet ports is cheap and easy.
And one underappreciated thing about the Mac is the teriffic support for multiple monitors when you add one or more video cards to supplement the built-in video. (And many Mac flight sims support multiple monitors, for simultaneous front and side views! : )
http://www.xlr8.com/ http://www.sonnettech.com/product/default.html http://www.powerlogix.com/products/products.html http://eshop.macsales.com/ http://www2.warehouse.com/dept_find.asp?dept%5Fid= 2618&cat=mac&sel=MacUPG
http://www.formac.com/html/shopformac.html
http://www.sonnettech.com/product/harmoni_g3.html
Note how there is a dendritic, tree-like structure radiating outward from a central "trunk." I know crystals can sometimes grow with a dendritic structure, but consider the scale of the image: about 5 meters per pixel. These are huge structures.
Also note that they appear to rise above the surface to a significant height. Sunlight is coming from the bottom of this image; the ground is bright on that side of the objects, and in shadow on the other side.
He nicknamed the organism the "Zolax." (Scroll two-thirds of the way down the page to see it.) If it resembles any earth organism, I would say the tarantula -- although it seems to have a half-dozen or so "tentacles," rather than articulated legs. If you look closely at the lower-left corner of the image, you'll even see one of the tentacles in contact with the ground. The point where it's attached to the body is hidden behind the rock, and it's casting a shadow! If this is a hoax, the hoaxer showed admirable attention to detail.
Disclaimer: the other purported anomalies on this web page are pretty dubious. (Don't you hate when some wacko points to a JPEG artifact and says "look, an artificial structure!" or "look, an organism!") I wish they weren't on the same page as the Zolax, because they hurt its credibility. Nevertheless, the Zolax looks like the real deal. It appears in both the left and right cameras simultaneously, so it can't be an image-processing artifact. It could be a hoax, but it would take a lot of effort to fake a stereo image like this.
It would be nice if we knew the time interval between the two frames -- then we'd have an idea of how fast this critter moves.
You seem to be using the Russian spelling, "Antarctida."
Keep in mind that if you want English-speaking persons to understand what the heck you are talking about, you should use "Antarctica."
Not to difficult to believe that all the still-unoxidized iron on the planet serves as the sink for the oxygen these critters produce -- assuming they produce oxygen at all.
Is this simple a clock speed multiple? For example, the PowerPC G4 currently tops out at 867 MHz. If it was made with this new gallium technique, would it then be able to be clocked up to 30 GHz?
Most of the stuff I've read about GaAs chips indicates they're used in RF signal processing. If Motorola makes them inexpensive, will they also show up as CPUs in desktops, laptops, and PDAs?
I believe GaAs works just like light-emitting diodes; LEDs don't get hot because electrical energy is converted directly to light, but at the same time there is no "cooling" of the LED taking place either. I don't know of anything that can convert heat directly into light. (Unless you count blackbody radiation given off at optical wavelenghts by very hot objects -- let's hope your CPU never gets that hot!)
According to Robert Zubrin you can set up a permanent base on Mars for $12 billion. That's what, only about 20% of Bill Gates' wealth? He could do this singlehandedly, and still have plenty of bucks left over for philanthropy.
(Although the act of giving our species a foothold on another planet would probably in itself be judged by future historians as the greatest act of philanthropy of all time.)
The only thing stopping him is a lack of vision. I'd be willing to forgive the lame software he foists upon me, if he turned us into a spacefaring species!
(Before people tell me his wealth is all on paper, and he wouldn't be worth nearly that much if he tried to sell his stock all at once, I know that. To build a Mars colony, he woulnd't have to sell his stock all at once. He would sell it a little bit at a time, over a 10 - 15 year period.)
Then how about defining the kg as "the rest mass of 2.1421235313 x 10^29 deterium atoms" (or whatever). That gets around your concern about whether to use the bound or unbound proton mass.
Point is, it can be defined in this manner, and it's not a circular definition.
This new apparatus is a very elaborate, and I'm sure very accurate, way to weigh their reference mass -- but the reference mass is still right at the heart of it. So how is this a fundamental change in the definition of the kg?
Similarly, the kg could be defined as "the mass of 4.32415234895 x 10^33 protons (or whatever -- pulled that number out of you know where).
There's nothing "circular" about that definition at all.
Not enough people have broadband yet. That's why the radio stations aren't seeing the increase in listenership they were expecting. They are giving up on their streams too soon. Come back in 5, 3, maybe 2 years and the economics of this will be completely different. Problem is, this has left them with a bad taste in their mouths and they may be disinclined to try streaming again even though the economics would support it.
AFTRA members deserve a somewhat larger fee when their work is streamed -- but not so much larger that it makes streaming unviable. They are just shooting themselves in the foot in that case. Same goes for the RIAA's streaming fee. What do you want to bet those fees were negotiate near the peak of the dot com bubble? Now that the bubble has burst, they should certainly be renegotiated. Better yet, the fee structure should be made a dynamic function of online listenership, so that streaming remains viable whether the online listenership grows as expected or not.
If this was the real deal, why would they sit on it for three years? That's a lot of revenues lost while they take their good old time commercializing the technology.
Let's see numbers that really can be compared across different platforms, such as:
How many minutes to compile these particular 100,000 lines of C++ code?
How many gigaflops?
When you say "even on ebay," you're implying that there are places where you're likely to find even lower prices than on eBay.
What might those places be?
How do "holes" move? When a hole moves, is it not actually an electron moving from one place to another -- leaving a new hole in the place where it left, and filling the hole in the place where it ends up?
If so, I don't see the difference between electrons carrying current and holes carrying current.
I can't believe the DOJ didn't use the bootloader issue in the trial. I agree with the article that it's a far worse anticompetitive practice than bundling a browser.
By the way, my Mac is quad-booting LinuxPPC, Darwin, OS X, and OS 9. Setting this up was easy!
By breaking the patent on AIDS drugs, Brazil is definately keeping their long-term interests in mind
Yes, there's no question that Brazil benefits from this move. But the human race as a whole suffers. It's a net loss to humanity.
Taking the argument to extremes often helps. What if there was a drug so insanely resource-intensive to develop that the pharmaceutical firm could only hope it recover its costs by charging $1 million per daily dose. Only Billy Gates and a handfull of others could afford to take this drug. And they are the only ones who should take it. 20 years later the patent will expire and you and I will be able to benefit from it too. But if the patent hadn't been honored, nobody, at any time, would ever benefit from it because it would have never been developed!
Drugs aren't developed in the name of humanity, they're developed for the benefit of stockholders. The fact that they also benefit humanity is fortuitous gravy. You may think that is a cold system, but it is a system that has worked exceedingly well. It is a system that has discovered hundreds of miraculous treatments.
In 20 years the patent will expire and then the third world country can start making the drug.
When patents are honored, we have the first world nations getting the benefit of the drug for 20 years, followed by everyone getting the benefit of the drug.
When patents are not honored, we have nobody getting the benefit of the drug because it's never developed in the first place.
You tell me which scenario is better.