T-bills pay interest because the government is borrowing your money, to do good works, and they PROMISE they will pay you back, with interest, Real Soon Now.
Holding gold is a strategy based on the premise that Real Soon Now will never happen.
I invite you to notice that the tech bubble popped, and those investors lost their investments. They knew the risks, they rolled the dice, YOU still got paid even though your.com cratered.
If your.com had made it, your investors risking their money on your blue-sky pitch and business plan notebook would have been part of the reason. Are you saying that they should have backed you for free, taken a much HIGHER risk than a T-bill, or a blue chip stock, for NO REASON AT ALL?
They must not teach Kirchoff's Laws of Circuit Analysis at your school.
Kirchoff's Current Law says that the sum of the currents into a node must equal the sum of the currents out of the node.
This is also applicable to programming: the number of times the processor enters a routine must equal the number of times it exits that routine (or it is stuck in the routine). (Note that spawning doesn't change this: spawning a new process is an entry, and that entry must die sometime, which is an exit.)
The same is true for dollars. Dollars flow into Wal-Mart. They flow out in various ways. Some flow out as salaries to employees. Some flow out as payments to suppliers, for the goods they sell to customers (which is what gets the customers to come into Wal-Mart in the first place, and bring money with them). Some flow as profits, some of which are returned to stockholders, some of which go to executive bonuses, some of which are retained to build more Wal-Marts, and some go to the government to pay for unemployment insurance and health care and God knows what all else the Democrats are spending money on this week to buy votes in November.
When Wal-Mart cuts salaries, that also allows them to cut prices to customers, which tends to bring more customers in and get MORE money, which continues to circulate. Yes, it hurts the Wal-Mart employees. There is, however, a limit on how far Wal-Mart can cut salaries: if they cut too far, employees notice that they can get paid better working for, say, CostCo, or slinging burgers at McNasty's, and they vote with their feet. There's a balancing act in there.
Now, if you personally feel really guilty about helping Wal-Mart pay really low salaries and thereby sell you goods and services for very low prices, you are of course free to go to another vendor and spending lots more money.
No, they are not "sucking money out of the system". They are CIRCULATING money in the system.
Economics 101: Money has no intrinsic value. By itself, outside the financial system, it is pretty pieces of colored, printed paper. Inside the system, it is an agreement to exchange goods and services for other goods and services.
Assume that our uber-bloodsucker takes down a few million and buys a yacht. Guess what? He's paying the salaries for the people who build that yacht, the people who maintain it, the people who crew it, the people who run the marinas. All of them are now working, doing things they (typically) enjoy more than digging ditches on a road crew somewhere, and putting food on THEIR tables.
Say he takes a vacation trip to, oh, say, Rio. He's paying the salaries for the guys at Boeing, who built the airplane. He's paying the salaries for the ramp rats at JFK. He's paying the salaries for the guys at the oil company who refined the fuel for the airplane. All of them continue to work and put food on their tables.
They get the big bucks, compared to the Java weenies you see immortalized in thedailywtf.com, because they generate high returns for their employers. Their employers, in turn, get bigger bucks for taking bigger risks than the programmers do. All of them cause money to CIRCULATE in the economy, in the never-ending exchanges of goods and services.
If you don't like it that someone else is making more money than you are, well, maybe you should have taken the tougher classes in school.
Also note: part of the price for being a high-frequency programmer is generally living and working in New York City. It ain't all roses.
OK, so if you're going to insist on a full cycle accounting for nuclear, you in all honesty must also insist on a full cycle accounting for coal.
That one gets ugly FAST. You have to include black lung disease fatalities and suffering. You have to include fly ash. You have to include transportation costs. (Burning coal requires moving a LOT of coal around the country.) If you believe that carbon dioxide is evil, you have to include carbon dioxide mitigation costs. And so on.
Read "The Health Hazards of NOT Going Nuclear", by Dr. Petr Beckmann. It is politically incorrect in the extreme, and very hard to find these days, but the data is good.
Coal is carbon (with impurities). Oxidation of carbon is exothermic and yields carbon dioxide.
Natural gas is hydrocarbons, compounds of carbon and hydrogen. As before, oxidation of carbon is exothermic. So is oxidation of hydrogen, which yields water. To get the same amount of energy, you can burn a certain amount of carbon, or a lesser amount of carbon and offset it with hydrogen, which gives you lower carbon dioxide emissions for the same energy output.
Methane is CH4, a hydrocarbon. It burns along with the rest of the natural gas. If you are getting methane in your exhaust, it is because you are running your fuel/air mixture too rich, and you aren't injecting enough air to burn the natural gas completely.
And, of course, burning uranium (or, better yet, thorium, but we don't have the engineering of the thorium fuel cycle worked out yet) in negative void coefficient pressurized water reactors is far better than burning coal or natural gas, since there are effectively NO greenhouse gas emissions from nuclear plants.
Besides, natural gas is far too valuable as a chemical processing feedstock to burn it to make electricity.
In the late 1970s, I was commuting by motorcycle in Austin, TX. I discovered that a long stretch of North Lamar, and another long stretch of Guadalupe, were set for a "green speed" of 35 mph. There was one stretch where I'd generally get caught, the Triangle cutover from Lamar to Guadalupe, but the rest was an easy cruise from almost to 183 on the north end to the University of Texas at Austin on the south end.
The vast majority of Austin commuters never realized it. The speed limit on those roads was 40 mph, and they all insisted on running at or above the limit between red lights.
Tektite I, in 1969, put four men in a habitat, and kept them there, for over 58 days. That was a record at the time. They were working during the dive, doing excursions. During Tektite II, multiple 10-20 day missions were carried out. NASA was involved in those.
A significant portion of the work in the Tektite projects was looking at human factors, specifically including psychology. Dr. Bob Helmreich of UT Austin was involved. (He was also the UT SCUBA club faculty sponsor for several years.)
Aquarius is 62' down. My recollection was that Tektite was at 45', that being the deepest you can use air for long-term saturation without risking whole-body oxygen toxicity issues.
There is NOTHING being done here that couldn't be done on dry land. ESA and the Russians are doing a similar project, all indoors in a big warehouse. Much of what they want to learn, about isolation psychology, they SHOULD be learning from the International Space Station, since they have crews spending much longer periods aboard ISS.
I don't like to put NASA down, but THIS project is a waste of time and money.
If the powersat is in geosynchronous orbit (UNLIKELY!), then the problem simplifies to "make sure the airliner doesn't fly over a particular section of ground". We do this all the time. It is called "restricted airspace". There's a chunk over Camp David, there's a chunk over Groom Lake (Area 51).
If the powersat is in low Earth orbit (far more likely), then the problem simplifies to "make sure the airliner doesn't fly through a moving region of airspace". We do this all the time, too. It is called "maintaining safe separation".
Every powersat concept I have ever seen included the design assumption that the receiving antenna array would be large enough to allow LOW beam density *AND* a certain amount of beam wander, so that *IF* an airplane flew through the beam, it would not do any harm to the airplane or anyone in it. This actually simplifies the beamforming and pointing problem quite a bit.
And it is worth mentioning in passing that Boeing and NASA tested beaming power by microwave, between two mountains several miles apart, at Goldstone in the 1960s.
Every college and university I ever heard of had a placement center, that existed for the sole purpose of facilitating interviewing of students about to graduate, and getting them hired. They are generally very good people, and helping you get hired is their job.
More to the point, the companies that interview you through the college placement center know you're a fresh grad, and unlikely to have any real experience.
Many years ago, at a RobotFest in Austin TX, I watched a dancer demonstrate triggering of multiple MIDI-controlled musical instruments from EMG sensors.
He danced, and the instruments played NON-preprogrammed accompaniment to his dance. If you watched CAREFULLY, you could see which muscle movements were triggering which sounds.
And he was GOOD. He'd obviously spent a LOT of years learning dance, and he'd obviously spent quite a bit of time mastering his new instruments.
Well, observe that the only significant difference between this test engagement and The Real Thing was the laser output power. Related to that is the fact that the test missile said "Yuh got me, pardner" instead of just dying spectacularly.
So most of the atmospheric issues would appear to have been solved.
Observe that the current generation of candidates for the "inbound craft" role are not covered with retro-reflecting beads, so the question is not applicable to those missiles. How much does your bead coating weigh, and how much does it reduce the throw weight and range of the missile if you just retrofit it?
Now, the Bad Guys could of course discard their current generation of missiles, and design, test, and build a whole new generation, that features enhanced laser survivability. They can't do that overnight, however, and it won't be free, or even cheap. If they do that, that's money they don't have for playing other nasty games.
Except for the HIGHLY nontrivial cost of designing, testing, fabricating, and deploying a whole new missile.
Except for the HIGHLY nontrivial cost of either building a whole new set of launch silos, or trashing out the existing missiles it replaced, because those existing missiles are still vulnerable to the Airborne Laser.
This is PRECISELY the continuing technological obsolescence and financial ruin scenario that Reagan promised Gorbachev, that eventually resulted in the reunification of Germany and the fall of the Soviet Union. It is a LOT cheaper for a technologically-superior adversary to develop a counter to your new weapon than for you to develop a whole new weapon that was immmune to his previous counter.
Read "The Strategy of Technology", by Kane, Possony, and Pournelle. Your library should be able to find a copy.
Are you familiar with the Gypsy Verification Environment and the Message Flow Modulator work, done by Don Good's group at The University of Texas at Austin in the late 1970s and early 1980s?
The Message Flow Modulator was a small (ca. 1000 lines of code, 1500 lines of type declarations and specifications) program, but it was by no means trivial. When it saw the acceptance test suite for the FIRST time, at the acceptance test at PAX River, in front of the customer, it passed. On the first time. No deviations, no waivers, no "yeah, but"s, no nothing, it passed.
The biggest issue, according to Don, was that it was expensive: at a time when 10 lines/man/day of allegedly-debugged, final, delivered code, with a known nonzero defect density, was considered typical, and acceptable, they were getting 1 line/man/day of absolutely-zero-defects delivered code. This is expensive, but one can readily conceive of environments where any measurable nonzero defect density is too high. (Like disk drives: if your bit error rate is high enough to measure, it's too high.)
My personal opinion is that the biggest issue they were going to encounter is that they didn't use C. Recall the resistance in this country to Ada, compared to the acceptance of Ada in Europe. (Recall also that Bell Labs, when asked to submit a DoD1 candidate based on C, politely declined, saying that C was not then and would never be robust enough to be a basis for highly reliable software.)
For the people who feel like ranting about nuclear waste, consider the sheer size of the installations that are being proposed for ground-level solar arrays or algae farms, and ask yourselves how many Astrodome-sized nuclear waste storage facilities could be built on that amount of land.
For the people who want to rant about the waste being horribly toxic for millenia (it isn't; the dangerous stuff is very, very short-lived), consider that the CO2 pollution model assumes that industrial carbon dioxide is deadly FOREVER - which it isn't, left to itself, with a little assist from Mother Nature, carbon dioxide turns into trees and grass and FOOD.
(Note that mine tailings, while considered radwaste by the Department of Energy, are actually LESS radioactive than the raw ore was, because the useful uranium has been TAKEN OUT of the mine tailings. If, as raw ore, it was safe enough to leave it in the ground, without any stewardship whatsoever, I really fail to understand how REDUCING its radioactivity has made it UNSAFE to put BACK in the ground.)
For some reason, environmentally-concerned citizens seem to have never learned basic arithmetic OR basic biology The carbon cycle, how animals consume oxygen and emit carbon dioxide, while plants consume carbon dioxide and emit oxygen, used to be taught in elementary school science lessons, and then again, in more detail, in high-school biology classes, at least in the US.
You have not thought the problem all the way through. You have neglected to consider the basic geometry involved.
The solar power satellites will be in low earth orbit, which means that they will be about 100 miles above the ground. As the Earth's radius is quite a bit more than 100 miles, the satellite's orbit will make a very close-fitting ring around the planet.
This means that the satellite will spend almost 50% of its time in shadow, on the far side of Earth from the Sun, and it will spend almost 50% of its time actually between the Earth and the Sun, casting a shadow on the Earth. Only for small periods during each orbit will it be clear of the planet.
During those small periods, it will be capturing sunlight that would not ordinarily reach the Earth, but go past it, converting SOME (but not all) of that sunlight into microwaves, and beaming it down. The remainder of the sunlight that it blocks from going any farther will be re-radiated, some of it into space, some of it at Earth.
While it is behind the Earth, of course, it is not intercepting sunlight at all.
While it is in front of the Earth, casting a shadow, it is capturing SOME of the sunlight that would have hit the Earth ANYWAY, and downconverting it to a wavelength that is not as readily absorbed by the atmosphere as the raw sunlight would have been. Of the energy that is not so downconverted, some of it will be re-radiated away from Earth, and some of it will be re-radiated toward Earth.
It must also be noted that the actual amount of energy intercepted by the satellite will be SMALL compared to the total amount of energy absorbed by Earth as a whole, for the simple reason that the satellite has a much smaller cross-sectional area than Earth does.
Executive Summary: Putting the satellite and receiving antenna array into the path DIMINISHES the total amount of energy reaching the Earth, by a small amount, from re-radiation into space. Of the part that does reach the Earth, SOME of it has been converted to a more convenient wavelength, so that it may be used for useful work BEFORE it becomes waste heat, as opposed to having been converted, by Earth itself, directly from raw sunlight to waste heat.
That's 1.3 kW/m^2 at ground level, in the form of sunlight.
You have a LOT of atmospheric attenuation (and consequent atmospheric heating) at optical wavelengths. In this case, the heating is a Good Thing: it makes the planet livable. Compare with the temperature variations on the moon, between shadow and sunlight.
I don't have a number for available solar power density in Earth orbit, but I would be very surprised if it was not a few (at least) orders of magnitude higher. (Considering that direct sunlight vs. clouds is about THREE ORDERS OF MAGNITUDE difference in attenuation, right there, as measured by any photographer's light meter...)
Actually, no, it won't heat the atmosphere significantly.
"Atmospheric heating from microwave loss" is another word for "atmospheric attenuation". The trick is you choose microwave frequencies that are not significantly absorbed by nitrogen, oxygen, and water (dihydrogen monoxide), and that knocks out your atmospheric attenuation problem right there.
This is Physics 102, people.
Your real losses are going to be in beamforming and beam wander. You fix beam wander by using a BIG receiving antenna (which also lets you use low power density in the beam: win-win).
On power: The object of the exercise is to put the solar arrays in space, cut out all the atmospheric attenuation due to air and clouds, and then send the power down using microwaves, on wavelengths that are not significantly attenuated by air and clouds.
On pointing: You've never heard of electronically-steered phased array radar, have you?
On efficiency: When the Jet Propulsion Lab tested microwave power beam technology in the 1960s, between two mountains several miles apart, they were hoping to get 63% transmission efficiency. They actually got over 80%. (I think the number was 88%, but don't quote me.)
The key concept on the efficiency question is that solar power in space is effectively unlimited, when compared with available solar power at ground level, because of atmospheric attenuation of light. (Photographers who shoot outdoors know all about this.) Once you have unlimited power at the head end, you don't really care very much about losses due to beamforming.
My source on this is a talk given by Jerry Pournelle in Austin TX in the late 1970s. His slides included photographs of the actual test apparatus, including one of the lit-up light board at the receiving site.
How many miles are you willing and able to walk to and from work, every day, in all weather conditions, year-round? More to the point: How many HOURS are you willing and able to walk to and from work, every day, in all weather conditions, year-round?
Figure 80 paces/minute cadence (standard military marching pace), 6 steps to 5 yards (standard military marching pace) and you get 12,000 ft/hour, or about 2.3 mph. If you live 5 miles from work, that's over two hours EACH WAY. On a bicycle, that's less than 30 minutes each way. In a car, you're probably looking at 10-15 minutes each way, with a lot of it being traffic lights and parking time and walking from house to car and parking lot to "workstation" (desk, assembly line, McDonalds drive-thru window,...).
You're looking for the section that starts "Senior Design Class (22.033) uses fusion energy for hydrogen fuel production". It includes links to PDFs of the final presentation and the final report.
Of course, the obvious NEXT questions are annoying things like:
1. What kind of numbers do you get with nuclear and/or fusion reactors, instead of biomass reactors or cornfields?
It is worth mentioning that the MIT Nuclear Engineering senior project recently was the engineering design of a fusion reactor to produce hydrogen for automotive fuel. One of the reasons given for producing hydrogen rather than electricity is that we don't have anything remotely resembling a power grid in the Northeast that could handle the output of a commercial-size fusion reactor.
And their design was apparently conservative: you could build it, starting TODAY.
2. How do you distribute the electricity from your biomass reactor or your solar field to the cars? See previous paragraph about power grid issues.
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You have obviously never heard of "loan capital".
T-bills pay interest because the government is borrowing your money, to do good works, and they PROMISE they will pay you back, with interest, Real Soon Now.
Holding gold is a strategy based on the premise that Real Soon Now will never happen.
I invite you to notice that the tech bubble popped, and those investors lost their investments. They knew the risks, they rolled the dice, YOU still got paid even though your .com cratered.
If your .com had made it, your investors risking their money on your blue-sky pitch and business plan notebook would have been part of the reason. Are you saying that they should have backed you for free, taken a much HIGHER risk than a T-bill, or a blue chip stock, for NO REASON AT ALL?
They must not teach Kirchoff's Laws of Circuit Analysis at your school.
Kirchoff's Current Law says that the sum of the currents into a node must equal the sum of the currents out of the node.
This is also applicable to programming: the number of times the processor enters a routine must equal the number of times it exits that routine (or it is stuck in the routine). (Note that spawning doesn't change this: spawning a new process is an entry, and that entry must die sometime, which is an exit.)
The same is true for dollars. Dollars flow into Wal-Mart. They flow out in various ways. Some flow out as salaries to employees. Some flow out as payments to suppliers, for the goods they sell to customers (which is what gets the customers to come into Wal-Mart in the first place, and bring money with them). Some flow as profits, some of which are returned to stockholders, some of which go to executive bonuses, some of which are retained to build more Wal-Marts, and some go to the government to pay for unemployment insurance and health care and God knows what all else the Democrats are spending money on this week to buy votes in November.
When Wal-Mart cuts salaries, that also allows them to cut prices to customers, which tends to bring more customers in and get MORE money, which continues to circulate. Yes, it hurts the Wal-Mart employees. There is, however, a limit on how far Wal-Mart can cut salaries: if they cut too far, employees notice that they can get paid better working for, say, CostCo, or slinging burgers at McNasty's, and they vote with their feet. There's a balancing act in there.
Now, if you personally feel really guilty about helping Wal-Mart pay really low salaries and thereby sell you goods and services for very low prices, you are of course free to go to another vendor and spending lots more money.
No, they are not "sucking money out of the system". They are CIRCULATING money in the system.
Economics 101: Money has no intrinsic value. By itself, outside the financial system, it is pretty pieces of colored, printed paper. Inside the system, it is an agreement to exchange goods and services for other goods and services.
Assume that our uber-bloodsucker takes down a few million and buys a yacht. Guess what? He's paying the salaries for the people who build that yacht, the people who maintain it, the people who crew it, the people who run the marinas. All of them are now working, doing things they (typically) enjoy more than digging ditches on a road crew somewhere, and putting food on THEIR tables.
Say he takes a vacation trip to, oh, say, Rio. He's paying the salaries for the guys at Boeing, who built the airplane. He's paying the salaries for the ramp rats at JFK. He's paying the salaries for the guys at the oil company who refined the fuel for the airplane. All of them continue to work and put food on their tables.
They get the big bucks, compared to the Java weenies you see immortalized in thedailywtf.com, because they generate high returns for their employers. Their employers, in turn, get bigger bucks for taking bigger risks than the programmers do. All of them cause money to CIRCULATE in the economy, in the never-ending exchanges of goods and services.
If you don't like it that someone else is making more money than you are, well, maybe you should have taken the tougher classes in school.
Also note: part of the price for being a high-frequency programmer is generally living and working in New York City. It ain't all roses.
OK, so if you're going to insist on a full cycle accounting for nuclear, you in all honesty must also insist on a full cycle accounting for coal.
That one gets ugly FAST. You have to include black lung disease fatalities and suffering. You have to include fly ash. You have to include transportation costs. (Burning coal requires moving a LOT of coal around the country.) If you believe that carbon dioxide is evil, you have to include carbon dioxide mitigation costs. And so on.
Read "The Health Hazards of NOT Going Nuclear", by Dr. Petr Beckmann. It is politically incorrect in the extreme, and very hard to find these days, but the data is good.
This is high-school chemistry.
Coal is carbon (with impurities). Oxidation of carbon is exothermic and yields carbon dioxide.
Natural gas is hydrocarbons, compounds of carbon and hydrogen. As before, oxidation of carbon is exothermic. So is oxidation of hydrogen, which yields water. To get the same amount of energy, you can burn a certain amount of carbon, or a lesser amount of carbon and offset it with hydrogen, which gives you lower carbon dioxide emissions for the same energy output.
Methane is CH4, a hydrocarbon. It burns along with the rest of the natural gas. If you are getting methane in your exhaust, it is because you are running your fuel/air mixture too rich, and you aren't injecting enough air to burn the natural gas completely.
And, of course, burning uranium (or, better yet, thorium, but we don't have the engineering of the thorium fuel cycle worked out yet) in negative void coefficient pressurized water reactors is far better than burning coal or natural gas, since there are effectively NO greenhouse gas emissions from nuclear plants.
Besides, natural gas is far too valuable as a chemical processing feedstock to burn it to make electricity.
In the late 1970s, I was commuting by motorcycle in Austin, TX. I discovered that a long stretch of North Lamar, and another long stretch of Guadalupe, were set for a "green speed" of 35 mph. There was one stretch where I'd generally get caught, the Triangle cutover from Lamar to Guadalupe, but the rest was an easy cruise from almost to 183 on the north end to the University of Texas at Austin on the south end.
The vast majority of Austin commuters never realized it. The speed limit on those roads was 40 mph, and they all insisted on running at or above the limit between red lights.
Are you sure about that?
The link is to the UPI site. UPI is a hard-news operation, and has been in the business for a very long time.
It has been DONE.
Tektite I, in 1969, put four men in a habitat, and kept them there, for over 58 days. That was a record at the time. They were working during the dive, doing excursions. During Tektite II, multiple 10-20 day missions were carried out. NASA was involved in those.
A significant portion of the work in the Tektite projects was looking at human factors, specifically including psychology. Dr. Bob Helmreich of UT Austin was involved. (He was also the UT SCUBA club faculty sponsor for several years.)
Aquarius is 62' down. My recollection was that Tektite was at 45', that being the deepest you can use air for long-term saturation without risking whole-body oxygen toxicity issues.
There is NOTHING being done here that couldn't be done on dry land. ESA and the Russians are doing a similar project, all indoors in a big warehouse. Much of what they want to learn, about isolation psychology, they SHOULD be learning from the International Space Station, since they have crews spending much longer periods aboard ISS.
I don't like to put NASA down, but THIS project is a waste of time and money.
If the powersat is in geosynchronous orbit (UNLIKELY!), then the problem simplifies to "make sure the airliner doesn't fly over a particular section of ground". We do this all the time. It is called "restricted airspace". There's a chunk over Camp David, there's a chunk over Groom Lake (Area 51).
If the powersat is in low Earth orbit (far more likely), then the problem simplifies to "make sure the airliner doesn't fly through a moving region of airspace". We do this all the time, too. It is called "maintaining safe separation".
Every powersat concept I have ever seen included the design assumption that the receiving antenna array would be large enough to allow LOW beam density *AND* a certain amount of beam wander, so that *IF* an airplane flew through the beam, it would not do any harm to the airplane or anyone in it. This actually simplifies the beamforming and pointing problem quite a bit.
And it is worth mentioning in passing that Boeing and NASA tested beaming power by microwave, between two mountains several miles apart, at Goldstone in the 1960s.
Every college and university I ever heard of had a placement center, that existed for the sole purpose of facilitating interviewing of students about to graduate, and getting them hired. They are generally very good people, and helping you get hired is their job.
More to the point, the companies that interview you through the college placement center know you're a fresh grad, and unlikely to have any real experience.
Try saying that when the man in question is your father.
Try saying that after watching your father's last week of life on hospice protocol.
Intellectually, you know there's nothing more that can be done but make him comfortable.
At gut level, it isn't the same.
(And in case you're wondering, the above is not hypothetical. I wish to God it was.)
Many years ago, at a RobotFest in Austin TX, I watched a dancer demonstrate triggering of multiple MIDI-controlled musical instruments from EMG sensors.
He danced, and the instruments played NON-preprogrammed accompaniment to his dance. If you watched CAREFULLY, you could see which muscle movements were triggering which sounds.
And he was GOOD. He'd obviously spent a LOT of years learning dance, and he'd obviously spent quite a bit of time mastering his new instruments.
How will the oil drippings and the tire residue affect the panel output?
Well, observe that the only significant difference between this test engagement and The Real Thing was the laser output power. Related to that is the fact that the test missile said "Yuh got me, pardner" instead of just dying spectacularly.
So most of the atmospheric issues would appear to have been solved.
Observe that the current generation of candidates for the "inbound craft" role are not covered with retro-reflecting beads, so the question is not applicable to those missiles. How much does your bead coating weigh, and how much does it reduce the throw weight and range of the missile if you just retrofit it?
Now, the Bad Guys could of course discard their current generation of missiles, and design, test, and build a whole new generation, that features enhanced laser survivability. They can't do that overnight, however, and it won't be free, or even cheap. If they do that, that's money they don't have for playing other nasty games.
Routine sorties would be really cheap compared to what it would cost to replace, say, Seattle or Los Angeles after Kim Jong-Il successfully nuked it.
Nobody ever said freedom was free.
Well, in theory, nothing.
Except for the HIGHLY nontrivial cost of designing, testing, fabricating, and deploying a whole new missile.
Except for the HIGHLY nontrivial cost of either building a whole new set of launch silos, or trashing out the existing missiles it replaced, because those existing missiles are still vulnerable to the Airborne Laser.
This is PRECISELY the continuing technological obsolescence and financial ruin scenario that Reagan promised Gorbachev, that eventually resulted in the reunification of Germany and the fall of the Soviet Union. It is a LOT cheaper for a technologically-superior adversary to develop a counter to your new weapon than for you to develop a whole new weapon that was immmune to his previous counter.
Read "The Strategy of Technology", by Kane, Possony, and Pournelle. Your library should be able to find a copy.
Are you familiar with the Gypsy Verification Environment and the Message Flow Modulator work, done by Don Good's group at The University of Texas at Austin in the late 1970s and early 1980s?
The Message Flow Modulator was a small (ca. 1000 lines of code, 1500 lines of type declarations and specifications) program, but it was by no means trivial. When it saw the acceptance test suite for the FIRST time, at the acceptance test at PAX River, in front of the customer, it passed. On the first time. No deviations, no waivers, no "yeah, but"s, no nothing, it passed.
The biggest issue, according to Don, was that it was expensive: at a time when 10 lines/man/day of allegedly-debugged, final, delivered code, with a known nonzero defect density, was considered typical, and acceptable, they were getting 1 line/man/day of absolutely-zero-defects delivered code. This is expensive, but one can readily conceive of environments where any measurable nonzero defect density is too high. (Like disk drives: if your bit error rate is high enough to measure, it's too high.)
My personal opinion is that the biggest issue they were going to encounter is that they didn't use C. Recall the resistance in this country to Ada, compared to the acceptance of Ada in Europe. (Recall also that Bell Labs, when asked to submit a DoD1 candidate based on C, politely declined, saying that C was not then and would never be robust enough to be a basis for highly reliable software.)
Dude, there already *IS* a viable long term alternative to fossil fuels for baseload electrical power, heating, cooking and transportation.
It is called "nuclear".
See "The Economics of Nuclear Power" at http://www.world-nuclear.org/info/inf02.html.
For the people who feel like ranting about nuclear waste, consider the sheer size of the installations that are being proposed for ground-level solar arrays or algae farms, and ask yourselves how many Astrodome-sized nuclear waste storage facilities could be built on that amount of land.
For the people who want to rant about the waste being horribly toxic for millenia (it isn't; the dangerous stuff is very, very short-lived), consider that the CO2 pollution model assumes that industrial carbon dioxide is deadly FOREVER - which it isn't, left to itself, with a little assist from Mother Nature, carbon dioxide turns into trees and grass and FOOD.
(Note that mine tailings, while considered radwaste by the Department of Energy, are actually LESS radioactive than the raw ore was, because the useful uranium has been TAKEN OUT of the mine tailings. If, as raw ore, it was safe enough to leave it in the ground, without any stewardship whatsoever, I really fail to understand how REDUCING its radioactivity has made it UNSAFE to put BACK in the ground.)
For some reason, environmentally-concerned citizens seem to have never learned basic arithmetic OR basic biology The carbon cycle, how animals consume oxygen and emit carbon dioxide, while plants consume carbon dioxide and emit oxygen, used to be taught in elementary school science lessons, and then again, in more detail, in high-school biology classes, at least in the US.
You have not thought the problem all the way through. You have neglected to consider the basic geometry involved.
The solar power satellites will be in low earth orbit, which means that they will be about 100 miles above the ground. As the Earth's radius is quite a bit more than 100 miles, the satellite's orbit will make a very close-fitting ring around the planet.
This means that the satellite will spend almost 50% of its time in shadow, on the far side of Earth from the Sun, and it will spend almost 50% of its time actually between the Earth and the Sun, casting a shadow on the Earth. Only for small periods during each orbit will it be clear of the planet.
During those small periods, it will be capturing sunlight that would not ordinarily reach the Earth, but go past it, converting SOME (but not all) of that sunlight into microwaves, and beaming it down. The remainder of the sunlight that it blocks from going any farther will be re-radiated, some of it into space, some of it at Earth.
While it is behind the Earth, of course, it is not intercepting sunlight at all.
While it is in front of the Earth, casting a shadow, it is capturing SOME of the sunlight that would have hit the Earth ANYWAY, and downconverting it to a wavelength that is not as readily absorbed by the atmosphere as the raw sunlight would have been. Of the energy that is not so downconverted, some of it will be re-radiated away from Earth, and some of it will be re-radiated toward Earth.
It must also be noted that the actual amount of energy intercepted by the satellite will be SMALL compared to the total amount of energy absorbed by Earth as a whole, for the simple reason that the satellite has a much smaller cross-sectional area than Earth does.
Executive Summary: Putting the satellite and receiving antenna array into the path DIMINISHES the total amount of energy reaching the Earth, by a small amount, from re-radiation into space. Of the part that does reach the Earth, SOME of it has been converted to a more convenient wavelength, so that it may be used for useful work BEFORE it becomes waste heat, as opposed to having been converted, by Earth itself, directly from raw sunlight to waste heat.
That's 1.3 kW/m^2 at ground level, in the form of sunlight.
You have a LOT of atmospheric attenuation (and consequent atmospheric heating) at optical wavelengths. In this case, the heating is a Good Thing: it makes the planet livable. Compare with the temperature variations on the moon, between shadow and sunlight.
I don't have a number for available solar power density in Earth orbit, but I would be very surprised if it was not a few (at least) orders of magnitude higher. (Considering that direct sunlight vs. clouds is about THREE ORDERS OF MAGNITUDE difference in attenuation, right there, as measured by any photographer's light meter...)
Actually, no, it won't heat the atmosphere significantly.
"Atmospheric heating from microwave loss" is another word for "atmospheric attenuation". The trick is you choose microwave frequencies that are not significantly absorbed by nitrogen, oxygen, and water (dihydrogen monoxide), and that knocks out your atmospheric attenuation problem right there.
This is Physics 102, people.
Your real losses are going to be in beamforming and beam wander. You fix beam wander by using a BIG receiving antenna (which also lets you use low power density in the beam: win-win).
On power: The object of the exercise is to put the solar arrays in space, cut out all the atmospheric attenuation due to air and clouds, and then send the power down using microwaves, on wavelengths that are not significantly attenuated by air and clouds.
On pointing: You've never heard of electronically-steered phased array radar, have you?
On efficiency: When the Jet Propulsion Lab tested microwave power beam technology in the 1960s, between two mountains several miles apart, they were hoping to get 63% transmission efficiency. They actually got over 80%. (I think the number was 88%, but don't quote me.)
The key concept on the efficiency question is that solar power in space is effectively unlimited, when compared with available solar power at ground level, because of atmospheric attenuation of light. (Photographers who shoot outdoors know all about this.) Once you have unlimited power at the head end, you don't really care very much about losses due to beamforming.
My source on this is a talk given by Jerry Pournelle in Austin TX in the late 1970s. His slides included photographs of the actual test apparatus, including one of the lit-up light board at the receiving site.
How many miles are you willing and able to walk to and from work, every day, in all weather conditions, year-round? More to the point: How many HOURS are you willing and able to walk to and from work, every day, in all weather conditions, year-round?
Figure 80 paces/minute cadence (standard military marching pace), 6 steps to 5 yards (standard military marching pace) and you get 12,000 ft/hour, or about 2.3 mph. If you live 5 miles from work, that's over two hours EACH WAY. On a bicycle, that's less than 30 minutes each way. In a car, you're probably looking at 10-15 minutes each way, with a lot of it being traffic lights and parking time and walking from house to car and parking lot to "workstation" (desk, assembly line, McDonalds drive-thru window, ...).
Now: How much is your time worth?
See http://web.mit.edu/nse/ and scroll down.
You're looking for the section that starts "Senior Design Class (22.033) uses fusion energy for hydrogen fuel production". It includes links to PDFs of the final presentation and the final report.
Of course, the obvious NEXT questions are annoying things like:
1. What kind of numbers do you get with nuclear and/or fusion reactors, instead of biomass reactors or cornfields?
It is worth mentioning that the MIT Nuclear Engineering senior project recently was the engineering design of a fusion reactor to produce hydrogen for automotive fuel. One of the reasons given for producing hydrogen rather than electricity is that we don't have anything remotely resembling a power grid in the Northeast that could handle the output of a commercial-size fusion reactor.
And their design was apparently conservative: you could build it, starting TODAY.
2. How do you distribute the electricity from your biomass reactor or your solar field to the cars? See previous paragraph about power grid issues.