1) The giant waste of money known as the SLS/Space Launch System, whose budget request was a huge 1,3 billion for this year, was instead given 2 billion. Congress clearly likes flushing money down the toilet.
2) The STMD/Space Technology Mission Directorate has been having its budget cut each year, and while it got a nominal rise this year, it was tasked with taking over RESTORE-L from the ISS's budget, so it's yet another negative. STMD is the branch which develops and tests new technologies that have the potential to make spaceflight cheaper and safer.
That said, everything else looks good. Commercial crew is fully funded. Planetary science was increased, meaning that they're not going to have to cut any of their ongoing missions as they would have had to in the president's budget, plutonium production is fully funded, etc - and of course the big Europa mission is on coursse. Even earth science got a boost, which surprises me given the composition of the current US congress.
I guess another option for the color variety would be just thermal radiation from the plasma sheath, with the temperature of the sheath indicating the colour. But that wouldn't allow for, for example, green light sabers, you never see a blackbody glow that looks green. Hmm... if the plasma wasn't in thermal equilibrium and was instead monoenergetic, that could theoretically yield whatever colour. But that would be harder to achieve and I can't envision a particular benefit to it...
Yes, because messing with a tablet while working on a car is totally reasonable. And as if I can just leave my tablet with the architect or lay out numerous full page-sized images on the table at the same time.
You're advocating for inferior solutions when superior solutions are available.
Not to mention that at one point while Luke is fiddling with it he actually has it pointed at his head;)
That said, I think the best thing about the light sabers is how it seems to automatically inspire in nerds the same thought process: "Okay, clearly there's no obvious way in compliance with the laws of physics to make something like that... what's the closest one could actually get?
The best I ever came up with is that it's a combination electric/plasma sword around a telescoping core. So the sound you hear on extension/retraction is a physical object expanding or retracting into the hilt. Inside it would be intense electromagnets creating a magnetic trap to circulate plasma along the exterior of the "saber". The plasma (generated by discharge in the hilt, like a plasma cutter) creates the glow, and a particular colour could be maintained by the injection of various ionizing gases that tend to emit at certain frequencies (this could be done on purpose for aesthetics, or they could just be a side effect of a coolant in the core boiling off). The plasma sheath would obviously be hot and destructive, but not intense enough on its own to, say, cut through thick metal doors or the like (if the plasma were that intense then it would be so bright you'd need welding goggles whenever you turned it on... unless you have it so high energy of its light emitted is in the X-ray spectrum, which would hardly be safer!). When the sword strikes a conductive object, however, it creates a electrical path between the plasma and its core, through the conductive surface. Detecting this, the hilt (which obviously requires an intense power source) pumps a tremendous current into the plasma (low voltage, high amperage, like is used in welding), with the central core acting as the return (either actively cooled or high-temperature superconductive). So ohmic heating is what does the melting of the target, like in welding.
Obviously the saber and the surface being cut would become extremely bright during the cutting (something not seen in the films), but that's pretty unavoidable when you're cutting metals (even normal earth metals, let alone whatever super metals exist "a long time ago in a galaxy far, far away") Also, I'm not sure how the magnetic fields would interact when two swords struck each other. If one envisions the interference causing the occasional unstable, temporary conductive path from the sheath to the core then that could explain the electrical cracking while they're in contact (obviously if it was a constant conductive path then they'd just cut right through each others' cores).
Star Wars kind of suffers from the same problem that Tolkien suffers from when one goes back and reads LotR (well, apart from his long-winded writing style): it all feels so cliche now, done to death a million times over. But that's not Tolkein's fault because, while he hardly invented the tropes in LotR, he's the one that really popularized them and inspired a million other works to pick up those tropes and run with them.
Star Wars certainly had its cheesy elements (a *lot* of them, and they don't start at the ewoks), but it did innovate too. My favorite example is the use of "crappy spaceships". It'd always generally been a sci-fi rule that, unless a ship has been recently damaged in combat, it's a shiny awesome wonder of technology. But the first space ship (after the initial chase scene) we're introduced to in Star Wars is a run-down piece of junk that's always breaking at the most inopportune times. Most of the rebel ships look like they're practically being held together by duct tape and poorly improvised spot welds.
If you take the prequels as canon then Obiwan is a really horrible manipulative liar in Ep 4. "Skywalker... now thats a name I haven't heard in a long time" - you mean since you chopped up his father and threw him into a volcano? "Vader betrayed and murdered your father" - we've always known that was a lie, but the fact that he was nearly Luke's father's killer and was lying about this raises it to a whole new level. The "pretending to never have seen the droids before" stuff, the "reluctant warrior" schtick when we know how he actually felt... there's no other way to interpret Ep 4 in conjunction with the prequels other than that he was feigning ignorance in an attempt to manipulate Luke into joining the rebellion in hopes of amending his earlier mistakes. And given that he'd lie (repeatedly) in order to do this... it makes you wonder whether it even was the empire who killed Owen and Beru, rather than Obiwan hiring someone to do it (not like there's any shortage of thugs for hire on Tattooine that he could have paid). I mean, seriously, "Only imperial storm troopers are so precise"? What sort of transparently false "evidence" was that?
And Luke... what kind of moron was he? He's handed a deadly weapon he's never seen before and immediately points it at his head, then opens it and starts swinging it around... then basically converts religions within minutes of meeting Obiwan. Not just converts, but becomes a zealot, scolding Han about not believing in the force literally like half an hour after he first hears of the concept. His only demonstration of "the force" at that point was having seen Obiwan get an unknown person in a white suit to agree with him, when there's tons of alternative possible explanations for that. Quite simply, if Luke were alive on Earth today, he'd be recruited into a cult in no time flat. Could be quite easy pickings for a group like Daesh as well.
Last time I printed was two days ago, it was a prototype honey jar label for my father. The ultimate labels will be silkscreened but before that we need to have a good sense of how they'd look in the real world. It took several sheets to get it right, even with reusing prints that ultimately didn't turn out right.
About two days before that I had to go fix something on my car and bring instructions and diagrams. Fumbling around on my phone while trying to do that would have been a real pain - especially since I was usually using the phone as a flashlight anyway.
About three days before that I printed out sample diagrams to take with to my next meeting with my architect.
Etc. What sort of world do you live in where you don't have to print stuff?
Don't just put their logo on it - write "Proudly donated by ((Company Name Here)). Allahu akhbar!" under their logo;)
Oh, and add the shahada so that some islamist group or another is sure to buy it. Plus, any sort of arabic writing looks scary to westerners. Or just get a black truck and ship it with a can of white paint and a brush so that they can do the rest;)
Printers are moving in the other direction - at least Epson. I finally gave up on feeding my ever-more-finicky Canon and got an Epson L355 with the ink tank system... god, I've been waiting so long for something like this. The paper now costs well more than the ink. The side effect is if I want something... I just print it. I don't have to worry about whether its worth the cost.
My only complaint is that they could have designed the refill bottles better... they're just pretty normal squeeze bottles, no leak protection on the openings, and no special splatter protection on the ink tank openings, so you have to be rather careful when filling tanks. But it's a minor complaint. Oh, okay one more: I can't tell it not to shut itself off - you can do that in Windows but I use Linux, and the android app (which is otherwise really excellent) doesn't have the ability to control that aspect.
Oh, I'm sorry, I didn't realize I was talking with an asshole, someone who would take a post where clearly no offense was meant and turn it into personal attacks.
The CO2 produced per unit weight is also better in Diesel engine.
This was accounted for in "while diesel engines are indeed higher efficiency". Usually in the ballpark of 15-20% for typical passenger vehicles in normal driving. The rest of the difference is generally the fuel density difference.
Diesel is actually easier to produce than gasoline.
It of course depends on the feedstock - some feedstocks have more light fractions (gasoline) while others have more heavy fractions (diesel). But indeed heavier fractions are more common and usually a bit cheaper, so they're used more commonly at present. I believe that the US average is currently around 9% of the feedstock's energy value is spent in the conversion to diesel vs. 15% for gasoline. But these numbers vary from year to year and it's been a while since I checked them last.
As for the future, the trend could go in either direction. Feedstocks like Venezuelan ultra heavy and Canadian bitumen naturally lend themselves toward heavier fuel oil fractions like diesel. On the other hand, synfuels generally naturally lend themselves toward lighter fractions like gasoline. So the question is where we'll get our oil from in the future.
While 30mpg isn't impressive, you shouldn't do the fallacy of comparing euro mileage figures with US mileage figures. Here's the three common errors:
1) (UK only): Imperial gallons are larger than US gallons. 2) (All europe): The NEDC is a more lax driving cycle than the EPA cycles and generally yields figures that are about 15% better. 3) (Diesels only): Europe uses diesels far more than the US. While diesel engines are indeed higher efficiency than gasoline engines, it's not as much as a direct MPG comparison would suggest - diesel is also a denser fuel than gasoline, aka you burn more mass of fuel per gallon that you burn. While that's irrelevant in terms of the price one pays at the pump, if what one cares about is CO2 emissions or the consequences of oil production, then it is relevant.
But back to the original case... no, 30mpg is not at all impressive this day in age.... even US 30mpg gasoline.
A car's vulnerability to lateral gusts is a combination of not just its mass, but also its cross section and its lateral drag coefficient. Unfortunately the effects of winds not directly aligned forward/backwards are often ignored on cars, which is unfortunate - even ignoring gusts, you can have a very streamlined car whose drag coefficient goes to heck because it starts facing crosswinds. Part of that stream that you're working so hard to keep laminar and attached suddenly plunges off over the edge of your car in an uncontrolled manner and detaches - that's not a good thing, and it doesn't take that strong of winds to happen! It's something that's starting to get increasing attention, and hopefully will even moreso in the future - because a car's vulnerability to gusts and its fuel economy are tied together in the real world, particularly in windy areas. Some well-placed vortex generators over the doors for example could really help with both, maybe a sort of horizontal kammback approach as well.
From the article, it's not a special alloy, just a heat process. I don't know if that would affect the corrosion rate, mind you - obviously it's concerning if they use less metal. Still, bare minimum, it shouldn't affect one's ability to galvanize it.
Neutron activation is a very familiar issue, one that's been dealt with at fission plants for ages. Fusion neutrons are more penetrating, but it's hardly a show stopper. And with fusion you have a lot more freedom about what exactly you want to get activated. The downside is that you need to design a lithium blanket and have most of the neutrons absorbed by it in order to breed your fuel.
It's certainly an issue, but hardly the *main* issue. The reason that we don't have fusion power plants today has nothing to do with neutrons. It's about having enough fusion happen in the plasma to make up for the losses in terms of all of the energy one has to pump into the system (actually, many times more than that, in order to be enough in the black to make a profit selling power after paying for your capital and ongoing costs). The more of the energy you put in that gets cast back out in some form or another that ends up as heat, the more in the red you are (thanks to Carnot losses). You need the plasma to stay hot - *very, very hot* - in order to fuse at a rate that gives off many more times power than you're putting in and which is getting thrown back out as heat. And that's been the showstopper for so long, and why scale is so important.
What you call "support force" I call "gravity losses" - see above:). The first stage pays both aero losses and most of the gravity losses, which usually eat up what would otherwise be an additional 1000-1500 m/s delta-V per launch. And the first stage is only a third of the total burn time. And has to be a lot more acceleration-limited during the earliest parts of its flight to minimize aero losses, otherwise you waste even more energy fighting the air (and put more stress on your vehicle at max-Q, which means you'd have to build it stronger and heavier, aka, wasting even more energy). Falcon 9 doesn't even start its gravity turn until 55 seconds in - and first stage burnout is 160-185 seconds, so for a third of its flight there's no horizontal component at all.
So yes, there is some horizontal component. But the first stage's main task is like any other first stage's - getting the second stage out of that pesky atmosphere:) You may have noticed how the ratios of sizes of the side boosters - on rockets that use them - to the rockets they're attached to are far less than the ratios of a main stage to the stage stacked vertically over it. That is to say, your typical vertically stacked stage is dramatically larger than what sits on top of it, but side boosters are usually smaller than the rocket that they attach to. Sometimes that's in part due to the core having a less dense propellant combo (such as LOX/LH)... but a large part is due to the above - you want enough thrust in the atmosphere to minimize your time at low speeds and thus gravity losses, but not so much thrust that you face huge aero losses - and you ideally want burnout time once the craft gets out of the atmosphere.
You don't have to "draw off" energy - the plasma is more than happy to lose heat to its surroundings. The biggest challenge with fusion is to stop the plasma from giving up its energy too fast!
That said, for continuously operating toruses you do have to "draw off" the "ash" (helium) by means of an "exhaust" system that juts up into the outer reaches of the plasma stream (where the heavier helium concentrates), which is "a" challenge (the component is subject to a very hostile environment and faces huge thermal loads), but it's not a showstopper challenge by any means.
OTRAG takes things too far. Yes, propellant and raw materials costs are only a small fraction of the total, but that doesn't mean that you can just toss ISP out the door. When you have to make a veritable mountain to launch a tiny payload you're giving yourself massively increased overhead costs - and unlike propellant costs, overhead is a big part of rocketry costs. You're also putting yourself in a far harder situation concerning environmental permiting, and the heavy (frequent) staging requirements and heavy steel boosters mean your craft is basically a bomber. Also the need for massive staging greatly increases the risk of catastrophic failure - staging is one of the most frequent areas of failure - yet they want to shed vast numbers of stages on every launch with low-budget boosters.
They took very real concept - that mass production reduces costs, and propellant costs aren't that critical - and walked way too far with it. And it's worth pointing out that there's also a very real concept that is precisely opposite that which underlies OTRAG - the "Big Dumb Booster" concept, which argues that single huge stages tend to be far cheaper than numerous small stages. Both of these are facts and yet they contract each other;) I really think SpaceX hit the balance on this one: they pursued mass production, but not at the cost of performance or breaking things down too far. Because in rocketry performance really does matter, particularly on upper stages.
Maybe between Atlas II and Atlas V, but Atlas V shares a lot in common with Atlas III. Atlas III was a real learning experience, and it shows in what was changed between III and V - for example, dropping the first stage balloon tanks in favor of isogrid (balloon tanks give great performance but they get you in the handling costs). And III was of course an evolution of II - even though II and V now have relatively little in common.
Read "Atlas V Launch Vehicle Service Guide" Appendix A about the history of the family. It's clearly an evolution, not a new development. They even use the same RD-180s.
On the other hand, first stages are limited in how fast they can accelerate due to aerodynamic drag, and they face far more gravity losses. The first stage pays for most of the "losses" that the craft will encounter in its ascent. Lastly, the first stage is only 32% of the total burn time. The most important part of any first stage is to get the craft out of the atmosphere so that the second stage engine can be optimized for vacuum. A first stage can be built for more burn time, but its nozzle - having been optimized for atmospheric usage - won't be as efficient.
(and the answer concerning the ratio is "about 90%").
Slashdot Mirror
I'm curious as to how Slashdotters would react if I were to post a giant Star Wars spoiler here.
Please explain why SLS makes any sense whatsoever.
... except for two things:
1) The giant waste of money known as the SLS/Space Launch System, whose budget request was a huge 1,3 billion for this year, was instead given 2 billion. Congress clearly likes flushing money down the toilet.
2) The STMD/Space Technology Mission Directorate has been having its budget cut each year, and while it got a nominal rise this year, it was tasked with taking over RESTORE-L from the ISS's budget, so it's yet another negative. STMD is the branch which develops and tests new technologies that have the potential to make spaceflight cheaper and safer.
That said, everything else looks good. Commercial crew is fully funded. Planetary science was increased, meaning that they're not going to have to cut any of their ongoing missions as they would have had to in the president's budget, plutonium production is fully funded, etc - and of course the big Europa mission is on coursse. Even earth science got a boost, which surprises me given the composition of the current US congress.
I guess another option for the color variety would be just thermal radiation from the plasma sheath, with the temperature of the sheath indicating the colour. But that wouldn't allow for, for example, green light sabers, you never see a blackbody glow that looks green. Hmm... if the plasma wasn't in thermal equilibrium and was instead monoenergetic, that could theoretically yield whatever colour. But that would be harder to achieve and I can't envision a particular benefit to it...
Yes, because messing with a tablet while working on a car is totally reasonable. And as if I can just leave my tablet with the architect or lay out numerous full page-sized images on the table at the same time.
You're advocating for inferior solutions when superior solutions are available.
Not to mention that at one point while Luke is fiddling with it he actually has it pointed at his head ;)
That said, I think the best thing about the light sabers is how it seems to automatically inspire in nerds the same thought process: "Okay, clearly there's no obvious way in compliance with the laws of physics to make something like that... what's the closest one could actually get?
The best I ever came up with is that it's a combination electric/plasma sword around a telescoping core. So the sound you hear on extension/retraction is a physical object expanding or retracting into the hilt. Inside it would be intense electromagnets creating a magnetic trap to circulate plasma along the exterior of the "saber". The plasma (generated by discharge in the hilt, like a plasma cutter) creates the glow, and a particular colour could be maintained by the injection of various ionizing gases that tend to emit at certain frequencies (this could be done on purpose for aesthetics, or they could just be a side effect of a coolant in the core boiling off). The plasma sheath would obviously be hot and destructive, but not intense enough on its own to, say, cut through thick metal doors or the like (if the plasma were that intense then it would be so bright you'd need welding goggles whenever you turned it on... unless you have it so high energy of its light emitted is in the X-ray spectrum, which would hardly be safer!). When the sword strikes a conductive object, however, it creates a electrical path between the plasma and its core, through the conductive surface. Detecting this, the hilt (which obviously requires an intense power source) pumps a tremendous current into the plasma (low voltage, high amperage, like is used in welding), with the central core acting as the return (either actively cooled or high-temperature superconductive). So ohmic heating is what does the melting of the target, like in welding.
Obviously the saber and the surface being cut would become extremely bright during the cutting (something not seen in the films), but that's pretty unavoidable when you're cutting metals (even normal earth metals, let alone whatever super metals exist "a long time ago in a galaxy far, far away") Also, I'm not sure how the magnetic fields would interact when two swords struck each other. If one envisions the interference causing the occasional unstable, temporary conductive path from the sheath to the core then that could explain the electrical cracking while they're in contact (obviously if it was a constant conductive path then they'd just cut right through each others' cores).
That's the best I ever came up with ;)
Star Wars kind of suffers from the same problem that Tolkien suffers from when one goes back and reads LotR (well, apart from his long-winded writing style): it all feels so cliche now, done to death a million times over. But that's not Tolkein's fault because, while he hardly invented the tropes in LotR, he's the one that really popularized them and inspired a million other works to pick up those tropes and run with them.
Star Wars certainly had its cheesy elements (a *lot* of them, and they don't start at the ewoks), but it did innovate too. My favorite example is the use of "crappy spaceships". It'd always generally been a sci-fi rule that, unless a ship has been recently damaged in combat, it's a shiny awesome wonder of technology. But the first space ship (after the initial chase scene) we're introduced to in Star Wars is a run-down piece of junk that's always breaking at the most inopportune times. Most of the rebel ships look like they're practically being held together by duct tape and poorly improvised spot welds.
If you take the prequels as canon then Obiwan is a really horrible manipulative liar in Ep 4. "Skywalker... now thats a name I haven't heard in a long time" - you mean since you chopped up his father and threw him into a volcano? "Vader betrayed and murdered your father" - we've always known that was a lie, but the fact that he was nearly Luke's father's killer and was lying about this raises it to a whole new level. The "pretending to never have seen the droids before" stuff, the "reluctant warrior" schtick when we know how he actually felt... there's no other way to interpret Ep 4 in conjunction with the prequels other than that he was feigning ignorance in an attempt to manipulate Luke into joining the rebellion in hopes of amending his earlier mistakes. And given that he'd lie (repeatedly) in order to do this... it makes you wonder whether it even was the empire who killed Owen and Beru, rather than Obiwan hiring someone to do it (not like there's any shortage of thugs for hire on Tattooine that he could have paid). I mean, seriously, "Only imperial storm troopers are so precise"? What sort of transparently false "evidence" was that?
And Luke... what kind of moron was he? He's handed a deadly weapon he's never seen before and immediately points it at his head, then opens it and starts swinging it around... then basically converts religions within minutes of meeting Obiwan. Not just converts, but becomes a zealot, scolding Han about not believing in the force literally like half an hour after he first hears of the concept. His only demonstration of "the force" at that point was having seen Obiwan get an unknown person in a white suit to agree with him, when there's tons of alternative possible explanations for that. Quite simply, if Luke were alive on Earth today, he'd be recruited into a cult in no time flat. Could be quite easy pickings for a group like Daesh as well.
Last time I printed was two days ago, it was a prototype honey jar label for my father. The ultimate labels will be silkscreened but before that we need to have a good sense of how they'd look in the real world. It took several sheets to get it right, even with reusing prints that ultimately didn't turn out right.
About two days before that I had to go fix something on my car and bring instructions and diagrams. Fumbling around on my phone while trying to do that would have been a real pain - especially since I was usually using the phone as a flashlight anyway.
About three days before that I printed out sample diagrams to take with to my next meeting with my architect.
Etc. What sort of world do you live in where you don't have to print stuff?
Don't just put their logo on it - write "Proudly donated by ((Company Name Here)). Allahu akhbar!" under their logo ;)
Oh, and add the shahada so that some islamist group or another is sure to buy it. Plus, any sort of arabic writing looks scary to westerners. Or just get a black truck and ship it with a can of white paint and a brush so that they can do the rest ;)
Printers are moving in the other direction - at least Epson. I finally gave up on feeding my ever-more-finicky Canon and got an Epson L355 with the ink tank system... god, I've been waiting so long for something like this. The paper now costs well more than the ink. The side effect is if I want something... I just print it. I don't have to worry about whether its worth the cost.
My only complaint is that they could have designed the refill bottles better... they're just pretty normal squeeze bottles, no leak protection on the openings, and no special splatter protection on the ink tank openings, so you have to be rather careful when filling tanks. But it's a minor complaint. Oh, okay one more: I can't tell it not to shut itself off - you can do that in Windows but I use Linux, and the android app (which is otherwise really excellent) doesn't have the ability to control that aspect.
Then what is "Enjoy your -1" supposed to mean?
Oh, I'm sorry, I didn't realize I was talking with an asshole, someone who would take a post where clearly no offense was meant and turn it into personal attacks.
This was accounted for in "while diesel engines are indeed higher efficiency". Usually in the ballpark of 15-20% for typical passenger vehicles in normal driving. The rest of the difference is generally the fuel density difference.
It of course depends on the feedstock - some feedstocks have more light fractions (gasoline) while others have more heavy fractions (diesel). But indeed heavier fractions are more common and usually a bit cheaper, so they're used more commonly at present. I believe that the US average is currently around 9% of the feedstock's energy value is spent in the conversion to diesel vs. 15% for gasoline. But these numbers vary from year to year and it's been a while since I checked them last.
As for the future, the trend could go in either direction. Feedstocks like Venezuelan ultra heavy and Canadian bitumen naturally lend themselves toward heavier fuel oil fractions like diesel. On the other hand, synfuels generally naturally lend themselves toward lighter fractions like gasoline. So the question is where we'll get our oil from in the future.
While 30mpg isn't impressive, you shouldn't do the fallacy of comparing euro mileage figures with US mileage figures. Here's the three common errors:
1) (UK only): Imperial gallons are larger than US gallons.
2) (All europe): The NEDC is a more lax driving cycle than the EPA cycles and generally yields figures that are about 15% better.
3) (Diesels only): Europe uses diesels far more than the US. While diesel engines are indeed higher efficiency than gasoline engines, it's not as much as a direct MPG comparison would suggest - diesel is also a denser fuel than gasoline, aka you burn more mass of fuel per gallon that you burn. While that's irrelevant in terms of the price one pays at the pump, if what one cares about is CO2 emissions or the consequences of oil production, then it is relevant.
But back to the original case... no, 30mpg is not at all impressive this day in age.... even US 30mpg gasoline.
Couldn't they just have the pieces be locally thicker in the locations where there's going to be spot welds to account for the localized weaknesses?
A car's vulnerability to lateral gusts is a combination of not just its mass, but also its cross section and its lateral drag coefficient. Unfortunately the effects of winds not directly aligned forward/backwards are often ignored on cars, which is unfortunate - even ignoring gusts, you can have a very streamlined car whose drag coefficient goes to heck because it starts facing crosswinds. Part of that stream that you're working so hard to keep laminar and attached suddenly plunges off over the edge of your car in an uncontrolled manner and detaches - that's not a good thing, and it doesn't take that strong of winds to happen! It's something that's starting to get increasing attention, and hopefully will even moreso in the future - because a car's vulnerability to gusts and its fuel economy are tied together in the real world, particularly in windy areas. Some well-placed vortex generators over the doors for example could really help with both, maybe a sort of horizontal kammback approach as well.
From the article, it's not a special alloy, just a heat process. I don't know if that would affect the corrosion rate, mind you - obviously it's concerning if they use less metal. Still, bare minimum, it shouldn't affect one's ability to galvanize it.
Neutron activation is a very familiar issue, one that's been dealt with at fission plants for ages. Fusion neutrons are more penetrating, but it's hardly a show stopper. And with fusion you have a lot more freedom about what exactly you want to get activated. The downside is that you need to design a lithium blanket and have most of the neutrons absorbed by it in order to breed your fuel.
It's certainly an issue, but hardly the *main* issue. The reason that we don't have fusion power plants today has nothing to do with neutrons. It's about having enough fusion happen in the plasma to make up for the losses in terms of all of the energy one has to pump into the system (actually, many times more than that, in order to be enough in the black to make a profit selling power after paying for your capital and ongoing costs). The more of the energy you put in that gets cast back out in some form or another that ends up as heat, the more in the red you are (thanks to Carnot losses). You need the plasma to stay hot - *very, very hot* - in order to fuse at a rate that gives off many more times power than you're putting in and which is getting thrown back out as heat. And that's been the showstopper for so long, and why scale is so important.
What you call "support force" I call "gravity losses" - see above :). The first stage pays both aero losses and most of the gravity losses, which usually eat up what would otherwise be an additional 1000-1500 m/s delta-V per launch. And the first stage is only a third of the total burn time. And has to be a lot more acceleration-limited during the earliest parts of its flight to minimize aero losses, otherwise you waste even more energy fighting the air (and put more stress on your vehicle at max-Q, which means you'd have to build it stronger and heavier, aka, wasting even more energy). Falcon 9 doesn't even start its gravity turn until 55 seconds in - and first stage burnout is 160-185 seconds, so for a third of its flight there's no horizontal component at all.
So yes, there is some horizontal component. But the first stage's main task is like any other first stage's - getting the second stage out of that pesky atmosphere :) You may have noticed how the ratios of sizes of the side boosters - on rockets that use them - to the rockets they're attached to are far less than the ratios of a main stage to the stage stacked vertically over it. That is to say, your typical vertically stacked stage is dramatically larger than what sits on top of it, but side boosters are usually smaller than the rocket that they attach to. Sometimes that's in part due to the core having a less dense propellant combo (such as LOX/LH)... but a large part is due to the above - you want enough thrust in the atmosphere to minimize your time at low speeds and thus gravity losses, but not so much thrust that you face huge aero losses - and you ideally want burnout time once the craft gets out of the atmosphere.
Only after losing its heat to the LOX. The helium is heated by the engines.
And yes, all of this has more than been accounted for - although it can be fun to be a Slashdot Rocketician sometimes ;)
You don't have to "draw off" energy - the plasma is more than happy to lose heat to its surroundings. The biggest challenge with fusion is to stop the plasma from giving up its energy too fast!
That said, for continuously operating toruses you do have to "draw off" the "ash" (helium) by means of an "exhaust" system that juts up into the outer reaches of the plasma stream (where the heavier helium concentrates), which is "a" challenge (the component is subject to a very hostile environment and faces huge thermal loads), but it's not a showstopper challenge by any means.
OTRAG takes things too far. Yes, propellant and raw materials costs are only a small fraction of the total, but that doesn't mean that you can just toss ISP out the door. When you have to make a veritable mountain to launch a tiny payload you're giving yourself massively increased overhead costs - and unlike propellant costs, overhead is a big part of rocketry costs. You're also putting yourself in a far harder situation concerning environmental permiting, and the heavy (frequent) staging requirements and heavy steel boosters mean your craft is basically a bomber. Also the need for massive staging greatly increases the risk of catastrophic failure - staging is one of the most frequent areas of failure - yet they want to shed vast numbers of stages on every launch with low-budget boosters.
They took very real concept - that mass production reduces costs, and propellant costs aren't that critical - and walked way too far with it. And it's worth pointing out that there's also a very real concept that is precisely opposite that which underlies OTRAG - the "Big Dumb Booster" concept, which argues that single huge stages tend to be far cheaper than numerous small stages. Both of these are facts and yet they contract each other ;) I really think SpaceX hit the balance on this one: they pursued mass production, but not at the cost of performance or breaking things down too far. Because in rocketry performance really does matter, particularly on upper stages.
Maybe between Atlas II and Atlas V, but Atlas V shares a lot in common with Atlas III. Atlas III was a real learning experience, and it shows in what was changed between III and V - for example, dropping the first stage balloon tanks in favor of isogrid (balloon tanks give great performance but they get you in the handling costs). And III was of course an evolution of II - even though II and V now have relatively little in common.
Read "Atlas V Launch Vehicle Service Guide" Appendix A about the history of the family. It's clearly an evolution, not a new development. They even use the same RD-180s.
Haha, love the idea ;) Maybe paint the words "Mun Or Bust" on the sides in sloppy children's handwriting just for added emphasis ;)
On the other hand, first stages are limited in how fast they can accelerate due to aerodynamic drag, and they face far more gravity losses. The first stage pays for most of the "losses" that the craft will encounter in its ascent. Lastly, the first stage is only 32% of the total burn time. The most important part of any first stage is to get the craft out of the atmosphere so that the second stage engine can be optimized for vacuum. A first stage can be built for more burn time, but its nozzle - having been optimized for atmospheric usage - won't be as efficient.
(and the answer concerning the ratio is "about 90%").