Let us define a non-orthogonal, non-linear coordinate system, such that linear motion within that coordinate system will describe an elliptical orbit in a conventional cartesian system.
You will have to compute that coordinate system and thereby pay the computational cost of linearizing your equations of motion. Good luck trying to find such a coordinate system for more than two interacting bodies.
You can use all the fancy pointless transforms that you want, but a guy standing in a noninertial frame will still be able to tell that he is, in fact, under acceleration, and a guy standing in an intertial frame will still be under relativity.
No, from the point of view of doing useful physics, the earth centered model is wrong period. We are not in some postmodernist feel good fest where all of our work is just "models" and every model is okay except some models happen to be more useful. When we do physics, we are trying to figure out how the world really works. Mathematics is the language we use to describe our working model and explore its implications. In that sense, some models are more correct while others are incorrect. The correct ones embodies the correct understanding of the physics. The incorrect ones embody the wrong notions about how a system behaves.
In the past two decades, there have been many international projects that have floundered or soared in cost because of their joint nature. Notable ones are:
Eurofighter: billions over budget and over a decade behind schedule. Block one versions are just now entering service, sans important capabilities such as multirole strike. In contrast, both France's Rafale and Sweden's Grippen, initiated at the same time as Eurofighter, have now been in service with full multi-role capabilities for almost a decade.
War in Kosovo: Targeting by committee and lack of plan for ground war led to an extended air campaign that inflicted almost no damage on the Serbian military. Only heavy targeting of civilian economic targets led to a gradual Serbian capitulation, after they've uprooted a hundred thousand Albanians. Post war confusion and bungling nearly led to WWIII as Russians steamed into Kosovo airport and Wesley Clark ordered the NATO ground commander to eject them.
The lesson from these costly bungles is that other countries are every bit as bureacratic and inept as we are. Working with them will only add to, not ameliorate our own incompetence. Without a coherent vision and an efficient and powerful lead organization, internationalization of an effort will only add to cost and delay.
What's needed is for NASA to be born again in the exploratory spirit of its former self. The President has presented a space vision that, if you read between the lines, makes reform of the agency its centerpiece. He has given Sean O'Keefe a mandate, and now it's time for you to do your part. Give them the political backing they need to cut through the bureacratic tangle at NASA!
Relativity holds between non-accelerating frames of reference. In such frames, one can not perform a local experiment to determine one's velocity absolute velocity. One can only define a reference frame and perform an experiment to determine one's velocity relative to that frame. Hence, the concept is called relativity.
Orbital motion results from acceleration caused by gravity. One can measure acceleration locally at any point within the influence of the gravitational field. Thus, symmetry between difference frames of reference are broken, and a natural "center" is defined as one of the points where one experiences no acceleration. In reality, you never have a true "center" in a multibodied system such as our solar system. However, the Sun is so massive that we can say, to reasonable accuracy, that the center of our solar system is approximately at the position of the sun.
The money in the budget of the new exploration enterprise, as it is known at NASA, is not for all new programs, but includes funding for existing programs that will now fall under the new exploration bureaucracy. It includes $483 million for Project Prometheus, the nuclear power and propulsion program started in 2003 and $428 million for Project Constellation, the new name for the proposed Crew Exploration Vehicle (CEV). While the CEV is a new program, it replaces a similar effort known as the Orbital Space Plane.
From http://zeus.nascom.nasa.gov/~pbrekke/soho/spacewea ther/spnews.ps:
Long pipelines stretching hundreds of miles can also run afowl of solar storms. As the earth's magnetic
field becomes agitated, these moving magnetic fields near the earth's surface can induce currents to flow
in any conducting material like pipe lines or power lines. Over time, these currents can cause increased
corrosion and weakening of pipeline walls which are under very high pressure as the liquified gas is
pumped at the fastest possible speeds to make them commercially profitable.
Alaskan Oil Pipeline has been specially protected from corrosion caused by ground currents that are induced by geomagnetic
activity.
Older pipelines were not constructed with these safeguards built into their design, and this can lead to
catastrophic and tragic failures.
June 1989 Trans - Siberian Railway explosion
The New York Times Monday, June 5 1989 Front Page
"500 on 2 trains reported killed by soviet gas pipeline explosion"
On June 4, a powerful gasline explosion demolished part of the Trans-Siberian Tailroad engulfing two
passenger trains in flames. Rescue workers at the Ural Mountain site worked frantically to rescue
passengers. Of the 1200, all but 500 could be saved. Many of the victims were children bound for
holiday camps by the Black Sea. It happened Saturday night between the towns of Ufa and Asha.
Apparently gas from a leak in the pipe line was egnited by the two passing trains. The gas settled into
the valley that the trains were passing through at the time. Rumors of sabotage were wide spread among
the local population.
The most catastrophic gas/air deflagration in history was the natural gas
explosion in June of 1989 that killed about 500 Russians out of over 1,200 on
two passenger trains going through the Ural mountains. The trains went into an
invisible cloud of an ignitable gas/air mixture covering several hundred acres.
A mostly propane and butane mixture had escaped for hours from a broken
30-in.-diameter pipeline in the vicinity. Izvestiya, a prominent Soviet
newspaper, described a mile-long "flame front" as having consumed the trains. To
judge from pictures of the overturned, blackened cars, the twisted rails and
displaced railroad ties, the "flame front" was a blast wave of a deflagration
propagated from an ignition point some distance from the tracks. A fiery blast
wave traveling only a few hundred miles per hour and striking the cars on their
sides produced the dramatic impact effects on the cars and passengers, and
burned many of the killed and the survivors
William Safire, winner of the 1978 Pulitzer Prize for distinguished commentary, joined The New York Times in 1973 as a political columnist. He also writes a Sunday column, On Language, which has appeared in The New York Times Magazine since 1979. This column on grammar, usage, and etymology has led to the publication of 10 books and made him the most widely read writer on the English language.
Before joining The Times, Mr. Safire was a senior White House speechwriter for President Nixon. He had previously been a radio and television producer and a U.S. Army correspondent. He began his career as a reporter for The New York Herald Tribune. From 1955 to 1960, Safire was vice president of a public relations firm in New York City, then became president of his own firm. He was responsible for bringing Mr. Nixon and Nikita Khrushchev together in the 1959 Moscow kitchen debate. In 1968, he joined the campaign of Richard Nixon.
He is the author of Freedom (1987), a novel of Lincoln and the Civil War. His other novels include Full Disclosure (1977), Sleeper Spy (1995) and Scandalmonger (2000). His other titles include a dictionary, a history, anthologies and commentaries.
Mr. Safire was born on Dec. 17, 1929, and attended Syracuse University; a dropout after two years, he returned a generation later to deliver the commencement address and is now a trustee. Since 1995 he has served as a member of the Pulitzer Board. He is married, has two children and lives in suburban Washington, D.C.
The question is, are you going to let the machines sit there on Mars for a year as your crew is trying to get there. Remember that the Martian environment is incredibly dusty, and that nothing from earth has spent more than 90 days up and running on Mars. Now, are you going to be able to monitor the machines well enough to be able to say that they'll still work when the crew gets there? Actually, monitoring isn't even a problem since once you've launched your crew, you can't recall them no matter what happens during the year that it'll take them to get there.
A launch window to Mars comes every two years. The unmanned portions will probably cost many billions of dollars on their own. If you loose them, not only will you have to wait two years to try again, but you've also lost 10 billion dollars. With prospects like that, this is a one shot, do it on the first try or fail deal. If you do fail, you can kiss human exploration of Mars good bye for a nother couple of decades.
As for radiation, there's an estimated cosmic-ray dosag, and then there's the worst case scenario. You could hope for fair space weather, but how likely are you to get storms that will seriously harm the crew? With solar storm activity at record levels in the past year, basing crew protection around some average expected dosage doesn't sound so good. As for spinning the craft, that's just one more potential point of failure.
For a two year mission, you'll have to take a lot of stuff with you if you're not going to recycle everything and you want some margin of safety in case propellant production doesn't go as planned. You might be able to take enough raw materials, but where does that leave the instruments you need to do good science?
All in all, the reference design sounds like a very expensive and very risky flag waving exercise where the crew will be spending all of their time and effort just trying to survive. What we need to push forward in space is reasonably cost effective and safe missions on which one could do good science. Clearly, we are not at that point technologically.
Hopefully, the president's reforms at NASA and manned exploration program will move us in the right direction, technologically and organizationally.
Since kinetic energy is equal to one half the mass times the square of the velocity, the upper limit in the speed at which propellant is ejected puts a lower limit on the amount of propellant a spacecraft must carry. This sets a limitation in the amount of actual cargo that could be carried to Mars and the speed at which the cargo could get there.
Chemical rockets eject propellant at relatively low speed that gives rise to three crucial problems.
1. A mission will take at least one and a half years.
2. The spacecraft cannot carry and adequate amount of water for radiation shielding.
3. The spacecraft must make propellant and fuel for the return trip ON MARS.
As the Mars Reference Mission shows, such plans so exist, but are they really doable. They have a host of problems that may not be surmountable.
1. The missions are incredibly complex. If any part of the mission fails, the chances of survival for the crew will be slim. Given the 50% success rate of Mars missions to date, this doesn't look so good.
2. The combined effects of low gravity and inadequate radiation shielding (space craft can't carry the extra mass requred) may mean that astronauts will be physically very weak or even ill by the time they reach Mars.
3. A two year mission to Mars will require that astronauts recycle almost all of the resources aboard, including oxygen, food, and human waste. To date, such technology has never worked well enough for a two year mission. Biosphere 2, for example didn't work for still undetermined reason and it was right here on Earth.
Going to Mars using chemical rockets is a Hail Mary mission. Even if it worked once, it would not lead to any thing like the sort of routine exploratory activity that we want to see happen. What we need to do is develop nuclear propulsion, which promises an order of magnitude increase in spacecraft speed and cargo capacity.
But that's only because it has two extra execution units for 64 bit code. 64 bit software is not inherently faster.
Most people here would know this, but I just thought I might preemptively clear up any confusion.
A decade of Berman at the helm has proved that mindless action, tight outfits, gibberish Trek pseudoscience, and petty, artificial conflicts does not a compelling sci-fi series make.
It's time to replace him with some one who can put mystery, suspense, and yes, realistic characters back into Trek.
I've got an idea. Take a capable producer and a couple of good writers, not necessarily from sci-fi backgrounds. Over the course of a month, Have them spend a week at JPL, a week aboard a nuclear submarine , a week hanging out with David Blaine, and a week with Donald Trump. Afterwards, lock them in a cabin for a week and tell them to transport the characters they've met to the Trek universe. I'll eat my shoe if they can't come up with a blockbuster.
The flow will be both ways
on
The Future of NASA
·
· Score: 4, Interesting
NASA technology and expertise will flow to the military. Applicable military technologies will flow to NASA. This will benefit both sides as long as both sides think clearly about what technologies and costs could beneficially be shared and what technologies and capabilities should not.
In the past, for example, shuttle development costs grew as a result of military requirements. Let's hope that this will not happen again.
The general approach should be modular. For example, much of the data architecture, flight software, crew protection, and engine technology could be designed as modular components that plug into an overall standard. The military and NASA would then assemble their own spacecraft while benefiting from shared development costs and manufacturing overhead.
Those who wish to keep the military out of space have their heads buried in the sand. Today, a vaccuum of power exists in space because no country as of yet has the capability to project its power there. It would be foolish for the US not to strive to project power into space while we have an advantage. Because wheter we do or we do not, nations that decry our military efforts today will themselves grab for power when it is within their reach tomorrow. Treaties and regulations do not pacify conflict. Historically, they have only served to codify and legitimize balance of power and pervasiveness of justice that prevents conflict. When no such balance exists, using treaties and accords to contain conflict is like trying to wrap up fire with paper. Witness, for example, the Mideaster peace process.
How many people protested the Iraq War? Did that even give Bush pause?
How about the Kyoto convention. Out the window it went despite a massive amount of outcry from the environmental movement.
Same with energy policy. Here were all these people having flowery visions of solar and wind farms in other people's back yards, and Bush and crew held some closed meetings, decided on coal and fuel cells, and that was that.
One of the first things Bush did as president was to restart research into nuclear propulsion. This happened long before Columbia, IIRC.
Bush doesn't care about the more extreme environmentalists because they are simply never going to be a part of his support base. Next year, he will win reelection, and things like nuclear propulsion will have four yeas to develop enough bureaucratic momentum to perpetuate themselves. IMHO, that's a GOOD THING.
Now if only the administration will start being straightforward with the American people and start thinking more about protecting our freedoms instead of needlessly curtailing them.
What would really impress people is if he came out and said I am
nationalizing the pharmaceutical industry, and the world will no longer need or
want for the meds that will stem world suffering.
...Thereby making drug research a much more bureaucratic and much less
economically lucrative endeavor, ensuring that advances in pharmacology is set
back by decades.
Or, he could say I have decided to walk the walk, and get rid of all the
Weapons of Mass Destruction that the United States has both developed and
proliferated to mankind.
...Thereby altering the nuclear security balance and making the world an
unfathomably more dangerous place.
Or, he could say I have decided to fund new technologies that will free
us from the chains of fossil fuels, and bring about a new era in sustainable
energy.
...Thereby incurring economic cost that would make the budgetary deficit look
like chump change.
But no, instead he will wax wildly about Man's need to discover new
frontiers, to extend Man's reach into the universe. Look for wild ideas about
multinational corporations mining minerals on the surface of Mars, polluting it
just as we have done here on our own planet.
Considering the risks (meteorites, radiation, low grav environment, isolation), a 2 year mission to Mars (aka going to Mars on a prayer) will never happen, not when there's the potential for the American public to watch helplessly as a bunch of astronauts die a million miles from home over the course of agonizing weeks without any hope of rescue, and especially not when 2 of the last four Mars lander missions have failed.
Nuclear rockets might shrink the time for the trip from years to a couple of months. We have trouble doing tests of those here on Earth because their radiation output would make Chernobyl look like a minor leak, so any flight testing need to be conducted in space, where the environment is already high in radiation. Of course, you'd still need to launch the reactor fuel into space....
Nuclear Rockets Page (I can't vouch for the authoritativeness of this material but it looks interesting).
How about a plan to reduce our dependence on non-renewable sources of energy?
But, unlike the space program, our efforts would be spent working on several very earthly problems: climate change and dependence on imported fuel.
Great, as soon as there is an actual need to do that, we can talk. In the mean time, coal will satisfy our energy needs for the next fifty years and fuel cells will reduce our dependence on oil. We are already spending billions on research into creating more efficient power plants and fuel cells and storing the CO2 produced by coal burning. Throwing more money at the problem will just provide more supporting evidence for the law of diminishing returns.
We can and should go to space when the time is right. But right now there are pressing matters to deal with here on earth: War, Nukes, Climate Change, War, etc
And those social, economic and political problems will NEVER be solved by simple technological development. If we had better solar panels today, will there be less terrorists, less nukes and less pollution in the world tomorrow? Will better solar panels or more money to the State Department change the fundamental security calculations that lead countries to retain nuclear weapons, or end the conflicts, oppression, and squalor that lead to war? All the money that we have would not be enough to do that. Taking money out of space to spend on renewable energy in order to stop war and climate change is like trying to put out a barn fire by taking money out of feeding the cows in order to make more cheese.
On the other hand, money invested in getting to the space will stimulate technological development, increase our national competitiveness, and expand the knowledge of the human race. I think realistic thinking dictates that we need to do the latter.
You can sort nanotubes electrochemically, but currently the enrichment factor (1.2 or something in that neighborhood) is not great enough where you can assume your sample to be pure metal type or pure semi-conductor type. I do expect that electrochemical methods to improve rather quickly, but since the really sexy devices depend on individual nanotubes, it would always be wise to figure out exactly what types you're dealing with in an experiment.
Self organizing films are interesting as an assembly process, but testing out ideas for gate designs and such still more conveniently done lithographically. What Hongjie Dai's group does is that they pattern a chip full of repeating units of test circuitry, then deposit catalysts on to the correct sites so that, when nanotubes are grown by CVD, they end up exactly where you need them to be to test them. Then, out of the chip full of nonworking devices, you find the few that work, and run tests on them.
Finally, self assembly maybe cheaper, but not necessarily smaller, since these days one can get 5 nm ebeam lithography if one has a good setup and expert people. Typical single walled carbon nanotubes are half a nanometer to a nanometer in diameter, and neighboring devices have to be separated by at least 2 nanometers to prevent interference from electrons tunneling from one device to another. This means that self assembled devices can not be significantly smaller than a lithographically constructed device for laboratory testing purposes, though commercial fabs may have much more trouble producing 5 nm patterned wafers on a large scale.
The problem here was that carbon nanotubes were exposed to an intense flash of light, which broke bonds and altered their atomic structure. When this happened, heat built up. Since the nanotubes were not arranged in any particular pattern, heat could not dissipate readily, resulting in combustion (presence of oxygen being a necessary ingredient in ANY type of combustion).
Completely different process than what would happen in an integrated circuit. In that case, bonds are not broken. Instead, electrons travel ballistically (in an ideal case) down metal type carbon nanotubes, dissipating much less power than they would travelling down conventional materials. What heat there is gets channeled through the nanotubes into the underlying chip and gets dissipated the conventional way, through a heat spreader in the packaging.
Trust me, carbon nanotubes make good materials for integrated circuits, if only we could figure out how to assemble them.
Slashdot Mirror
You will have to compute that coordinate system and thereby pay the computational cost of linearizing your equations of motion. Good luck trying to find such a coordinate system for more than two interacting bodies.
You can use all the fancy pointless transforms that you want, but a guy standing in a noninertial frame will still be able to tell that he is, in fact, under acceleration, and a guy standing in an intertial frame will still be under relativity.
No, from the point of view of doing useful physics, the earth centered model is wrong period. We are not in some postmodernist feel good fest where all of our work is just "models" and every model is okay except some models happen to be more useful. When we do physics, we are trying to figure out how the world really works. Mathematics is the language we use to describe our working model and explore its implications. In that sense, some models are more correct while others are incorrect. The correct ones embodies the correct understanding of the physics. The incorrect ones embody the wrong notions about how a system behaves.
In the past two decades, there have been many international projects that have floundered or soared in cost because of their joint nature. Notable ones are:
Eurofighter: billions over budget and over a decade behind schedule. Block one versions are just now entering service, sans important capabilities such as multirole strike. In contrast, both France's Rafale and Sweden's Grippen, initiated at the same time as Eurofighter, have now been in service with full multi-role capabilities for almost a decade.
War in Kosovo: Targeting by committee and lack of plan for ground war led to an extended air campaign that inflicted almost no damage on the Serbian military. Only heavy targeting of civilian economic targets led to a gradual Serbian capitulation, after they've uprooted a hundred thousand Albanians. Post war confusion and bungling nearly led to WWIII as Russians steamed into Kosovo airport and Wesley Clark ordered the NATO ground commander to eject them.
The lesson from these costly bungles is that other countries are every bit as bureacratic and inept as we are. Working with them will only add to, not ameliorate our own incompetence. Without a coherent vision and an efficient and powerful lead organization, internationalization of an effort will only add to cost and delay.
What's needed is for NASA to be born again in the exploratory spirit of its former self. The President has presented a space vision that, if you read between the lines, makes reform of the agency its centerpiece. He has given Sean O'Keefe a mandate, and now it's time for you to do your part. Give them the political backing they need to cut through the bureacratic tangle at NASA!
Relativity holds between non-accelerating frames of reference. In such frames, one can not perform a local experiment to determine one's velocity absolute velocity. One can only define a reference frame and perform an experiment to determine one's velocity relative to that frame. Hence, the concept is called relativity.
Orbital motion results from acceleration caused by gravity. One can measure acceleration locally at any point within the influence of the gravitational field. Thus, symmetry between difference frames of reference are broken, and a natural "center" is defined as one of the points where one experiences no acceleration. In reality, you never have a true "center" in a multibodied system such as our solar system. However, the Sun is so massive that we can say, to reasonable accuracy, that the center of our solar system is approximately at the position of the sun.
Did Safire get his dates mixed up? There was a huge petroleum gas explosion in the trans-Siberian pipeline in June 1989.
From this site:
http://www.cia.gov/csi/studies/96unclass/farewell. htm
Goonie,
The question is, are you going to let the machines sit there on Mars for a year as your crew is trying to get there. Remember that the Martian environment is incredibly dusty, and that nothing from earth has spent more than 90 days up and running on Mars. Now, are you going to be able to monitor the machines well enough to be able to say that they'll still work when the crew gets there? Actually, monitoring isn't even a problem since once you've launched your crew, you can't recall them no matter what happens during the year that it'll take them to get there.
A launch window to Mars comes every two years. The unmanned portions will probably cost many billions of dollars on their own. If you loose them, not only will you have to wait two years to try again, but you've also lost 10 billion dollars. With prospects like that, this is a one shot, do it on the first try or fail deal. If you do fail, you can kiss human exploration of Mars good bye for a nother couple of decades.
As for radiation, there's an estimated cosmic-ray dosag, and then there's the worst case scenario. You could hope for fair space weather, but how likely are you to get storms that will seriously harm the crew? With solar storm activity at record levels in the past year, basing crew protection around some average expected dosage doesn't sound so good. As for spinning the craft, that's just one more potential point of failure.
For a two year mission, you'll have to take a lot of stuff with you if you're not going to recycle everything and you want some margin of safety in case propellant production doesn't go as planned. You might be able to take enough raw materials, but where does that leave the instruments you need to do good science?
All in all, the reference design sounds like a very expensive and very risky flag waving exercise where the crew will be spending all of their time and effort just trying to survive. What we need to push forward in space is reasonably cost effective and safe missions on which one could do
good science. Clearly, we are not at that point technologically.
Hopefully, the president's reforms at NASA and manned exploration program will move us in the right direction, technologically and organizationally.
Since kinetic energy is equal to one half the mass times the square of the velocity, the upper limit in the speed at which propellant is ejected puts a lower limit on the amount of propellant a spacecraft must carry. This sets a limitation in the amount of actual cargo that could be carried to Mars and the speed at which the cargo could get there.
Chemical rockets eject propellant at relatively low speed that gives rise to three crucial problems.
1. A mission will take at least one and a half years.
2. The spacecraft cannot carry and adequate amount of water for radiation shielding.
3. The spacecraft must make propellant and fuel for the return trip ON MARS.
As the Mars Reference Mission shows, such plans so exist, but are they really doable. They have a host of problems that may not be surmountable.
1. The missions are incredibly complex. If any part of the mission fails, the chances of survival for the crew will be slim. Given the 50% success rate of Mars missions to date, this doesn't look so good.
2. The combined effects of low gravity and inadequate radiation shielding (space craft can't carry the extra mass requred) may mean that astronauts will be physically very weak or even ill by the time they reach Mars.
3. A two year mission to Mars will require that astronauts recycle almost all of the resources aboard, including oxygen, food, and human waste. To date, such technology has never worked well enough for a two year mission. Biosphere 2, for example didn't work for still undetermined reason and it was right here on Earth.
Going to Mars using chemical rockets is a Hail Mary mission. Even if it worked once, it would not lead to any thing like the sort of routine exploratory activity that we want to see happen. What we need to do is develop nuclear propulsion, which promises an order of magnitude increase in spacecraft speed and cargo capacity.
Let's see:
Advertised as unlimited, but really isn't.
No clear guidelines or parameters with arbitrary threats of termination.
Thousands of affected users.
I think we have the makings of a class action law suit here.
But that's only because it has two extra execution units for 64 bit code. 64 bit software is not inherently faster. Most people here would know this, but I just thought I might preemptively clear up any confusion.
Or a copper line in a side pipe?
Heck, they can do this with Joss Whedon. ...shame on me for replying to my own post. :x
A decade of Berman at the helm has proved that mindless action, tight outfits, gibberish Trek pseudoscience, and petty, artificial conflicts does not a compelling sci-fi series make.
It's time to replace him with some one who can put mystery, suspense, and yes, realistic characters back into Trek.
I've got an idea. Take a capable producer and a couple of good writers, not necessarily from sci-fi backgrounds. Over the course of a month, Have them spend a week at JPL, a week aboard a nuclear submarine , a week hanging out with David Blaine, and a week with Donald Trump. Afterwards, lock them in a cabin for a week and tell them to transport the characters they've met to the Trek universe. I'll eat my shoe if they can't come up with a blockbuster.
NASA technology and expertise will flow to the military. Applicable military technologies will flow to NASA. This will benefit both sides as long as both sides think clearly about what technologies and costs could beneficially be shared and what technologies and capabilities should not.
In the past, for example, shuttle development costs grew as a result of military requirements. Let's hope that this will not happen again.
The general approach should be modular. For example, much of the data architecture, flight software, crew protection, and engine technology could be designed as modular components that plug into an overall standard. The military and NASA would then assemble their own spacecraft while benefiting from shared development costs and manufacturing overhead.
Those who wish to keep the military out of space have their heads buried in the sand. Today, a vaccuum of power exists in space because no country as of yet has the capability to project its power there. It would be foolish for the US not to strive to project power into space while we have an advantage. Because wheter we do or we do not, nations that decry our military efforts today will themselves grab for power when it is within their reach tomorrow. Treaties and regulations do not pacify conflict. Historically, they have only served to codify and legitimize balance of power and pervasiveness of justice that prevents conflict. When no such balance exists, using treaties and accords to contain conflict is like trying to wrap up fire with paper. Witness, for example, the Mideaster peace process.
Those who are interested in nuclear rocketry may want to check out NASA's Project Prometheus.
There's also an excellent write-up of present day and past efforts HERE.
How many people protested the Iraq War? Did that even give Bush pause?
How about the Kyoto convention. Out the window it went despite a massive amount of outcry from the environmental movement.
Same with energy policy. Here were all these people having flowery visions of solar and wind farms in other people's back yards, and Bush and crew held some closed meetings, decided on coal and fuel cells, and that was that.
One of the first things Bush did as president was to restart research into nuclear propulsion. This happened long before Columbia, IIRC.
Bush doesn't care about the more extreme environmentalists because they are simply never going to be a part of his support base. Next year, he will win reelection, and things like nuclear propulsion will have four yeas to develop enough bureaucratic momentum to perpetuate themselves. IMHO, that's a GOOD THING.
Now if only the administration will start being straightforward with the American people and start thinking more about protecting our freedoms instead of needlessly curtailing them.
What would really impress people is if he came out and said I am nationalizing the pharmaceutical industry, and the world will no longer need or want for the meds that will stem world suffering.
...Thereby making drug research a much more bureaucratic and much less economically lucrative endeavor, ensuring that advances in pharmacology is set back by decades.
Or, he could say I have decided to walk the walk, and get rid of all the Weapons of Mass Destruction that the United States has both developed and proliferated to mankind.
...Thereby altering the nuclear security balance and making the world an unfathomably more dangerous place.
Or, he could say I have decided to fund new technologies that will free us from the chains of fossil fuels, and bring about a new era in sustainable energy.
...Thereby incurring economic cost that would make the budgetary deficit look like chump change.
But no, instead he will wax wildly about Man's need to discover new frontiers, to extend Man's reach into the universe. Look for wild ideas about multinational corporations mining minerals on the surface of Mars, polluting it just as we have done here on our own planet.
Umm, I'll take option 4.
Considering the risks (meteorites, radiation, low grav environment,
isolation), a 2 year mission to Mars (aka going to Mars on a prayer) will never
happen, not when there's the potential for the American public to watch
helplessly as a bunch of astronauts die a million miles from home over the
course of agonizing weeks without any hope of rescue, and especially not when 2
of the last four Mars lander missions have failed.
Nuclear rockets might shrink the time for the trip from years to a couple of
months. We have trouble doing tests of those here on Earth because their radiation output would
make Chernobyl look like a minor leak, so any flight testing need to be conducted in space,
where the environment is already high in radiation. Of course, you'd still need to launch
the reactor fuel into space....
Nuclear Rockets Page
(I can't vouch for the authoritativeness of this material but it looks
interesting).
How about a plan to reduce our dependence on non-renewable sources of energy?
But, unlike the space program, our efforts would be spent working on several very earthly problems: climate change and dependence on imported fuel.
Great, as soon as there is an actual need to do that, we can talk. In the mean time, coal will satisfy our energy needs for the next fifty years and fuel cells will reduce our dependence on oil. We are already spending billions on research into creating more efficient power plants and fuel cells and storing the CO2 produced by coal burning. Throwing more money at the problem will just provide more supporting evidence for the law of diminishing returns.
We can and should go to space when the time is right. But right now there are pressing matters to deal with here on earth: War, Nukes, Climate Change, War, etc
And those social, economic and political problems will NEVER be solved by simple technological development. If we had better solar panels today, will there be less terrorists, less nukes and less pollution in the world tomorrow? Will better solar panels or more money to the State Department change the fundamental security calculations that lead countries to retain nuclear weapons, or end the conflicts, oppression, and squalor that lead to war? All the money that we have would not be enough to do that. Taking money out of space to spend on renewable energy in order to stop war and climate change is like trying to put out a barn fire by taking money out of feeding the cows in order to make more cheese.
On the other hand, money invested in getting to the space will stimulate technological development, increase our national competitiveness, and expand the knowledge of the human race. I think realistic thinking dictates that we need to do the latter.
You can sort nanotubes electrochemically, but currently the enrichment factor (1.2 or something in that neighborhood) is not great enough where you can assume your sample to be pure metal type or pure semi-conductor type. I do expect that electrochemical methods to improve rather quickly, but since the really sexy devices depend on individual nanotubes, it would always be wise to figure out exactly what types you're dealing with in an experiment.
Self organizing films are interesting as an assembly process, but testing out ideas for gate designs and such still more conveniently done lithographically. What Hongjie Dai's group does is that they pattern a chip full of repeating units of test circuitry, then deposit catalysts on to the correct sites so that, when nanotubes are grown by CVD, they end up exactly where you need them to be to test them. Then, out of the chip full of nonworking devices, you find the few that work, and run tests on them.
Finally, self assembly maybe cheaper, but not necessarily smaller, since these days one can get 5 nm ebeam lithography if one has a good setup and expert people. Typical single walled carbon nanotubes are half a nanometer to a nanometer in diameter, and neighboring devices have to be separated by at least 2 nanometers to prevent interference from electrons tunneling from one device to another. This means that self assembled devices can not be significantly smaller than a lithographically constructed device for laboratory testing purposes, though commercial fabs may have much more trouble producing 5 nm patterned wafers on a large scale.
Also, it'd be neat if they could base some kind of flash memory technology on this stuff too.
Nantero
The problem here was that carbon nanotubes were exposed to an intense flash of light, which broke bonds and altered their atomic structure. When this happened, heat built up. Since the nanotubes were not arranged in any particular pattern, heat could not dissipate readily, resulting in combustion (presence of oxygen being a necessary ingredient in ANY type of combustion).
Completely different process than what would happen in an integrated circuit. In that case, bonds are not broken. Instead, electrons travel ballistically (in an ideal case) down metal type carbon nanotubes, dissipating much less power than they would travelling down conventional materials. What heat there is gets channeled through the nanotubes into the underlying chip and gets dissipated the conventional way, through a heat spreader in the packaging.
Trust me, carbon nanotubes make good materials for integrated circuits, if only we could figure out how to assemble them.
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