Is Oil Depletion a real thing, and will it collapse nations?

[Kalaron]

Few small issues, one being that using it as a "transcontinental shuttle" is painfully retarded and was the first reason why this got laughed out. The second reason is precisely how bad chemical engines are and the third is in the massive amount of propellant you now have to expend for every mission involving the craft, which also involves hauling it up with another craft.
https://childrenofadeadearth.wordpress. ... kets-burn/
https://childrenofadeadearth.wordpress. ... h-baffles/
http://www.projectrho.com/public_html/r ... nelist.php
http://www.projectrho.com/public_html/r ... verse2.png
These links really contain a lot of the complexities of this issue, since this drive will actually be sorta unlikely to work given that it needs to carry a total of 24 kilometers a second of fuel to Titan, and at least twelve, bordering on thirteen back. More, probably, since they'll be carrying dead weight back in the form of unusable propellant. Oh and it'll take years to get back.

E: Also, NTR isn't a design so much as a class of rocket engine. It's a nuclear thermal rocket, and it's veritably the only rocket drive that be counted on for timely missions and good cargo.

1. I misunderstood what you meant by NTR in my last post. However, a nuclear thermal rocket has crappy thrust and specific impulse (if you don't play KSP, this is a measure of the efficiency of a rocket engine) within the atmosphere
2. This is designed for crewed missions to Mars, not Titan. Did you read the Wikipedia link!?
3. SpaceX plans to launch each BFR into low Earth orbit, launch a tanker to refuel it and then return to Earth, and send the other ship to Mars after being refuelled. Uncrewed cargo missions will also be sent to Mars to assemble a propellant plant on Mars that will make fuel via ISRU, so the ship can be refuelled on Mars for a direct flight back to Earth (possible due to Mars' lower gravity than Earth). Therefore, they don't need to carry additional fuel for returning.
4. Mars is closer than Titan, and a round trip may take up to 2 years

On the matter of NTRs: It's less a matter of firing the engine in atmosphere, and more a matter of needing to carry less crap up on a booster. For every kilogram of weight (including the dead propellant of your rocket) you need at least three and a half kilograms of active propellant (it's a good rule of thumb) to get it to orbit from the surface. As such, carrying a monumentally better engine up is going to be much, much better than having to carry more yet more fuel up.

For the other points, I thought you were trying to say they'd use it -or could use it- to bring fuel back from Titan like the base post was about, sorry
That said, the sheer ridiculous nature of their "shuttle" claim makes the whole thing reeks of the same technophilia as the Hyperloop, and the promise of bootstrapping a propellant plant has always been a long shot to me. However, Mars is a much closer target, so I'll wait to see whether the BFR is more of a Hyperloop or a Falcon.

1. And many nuclear malfunctions can also be prevented. For example, Three Mile Island could have been stopped by better warnings, and Chernobyl was a BS "safety test".
Also, a meltdown is usually just the core overheating. Usually the worst that happens is evacuating the plant and dumping the radioactive material; Chernobyl and Fukushima were what the Germans call GAU (German acronym for "Greatest Disaster Imaginable").

2. When somebody calls a source as reliable as Wikipedia "BS", the BS is likely on their side.

1. In other words, shit happens, and whatever safety measures people have in theory aren't used in practice. Better that happen with lower-stakes methods like wind and solar than with nuclear.

2. O RLY?

It's ironic because it'd happen even more rarely with newer, fail-safe reactors.
https://www.ne.anl.gov/About/hn/logos-w ... -psr.shtml

[Isilanka]

You know the funny thing ?
France, the most nuclear-fission reliant country in the world, could have used sodium cooling reactors from the get-go. Instead we used the classical technology of uranium bars and water cooling, building more than 40 reactors that are not safe and a nightmare to dismantle.
The reason ? None.

[Petrolheadia]

You know the funny thing ?
France, the most nuclear-fission reliant country in the world, could have used sodium cooling reactors from the get-go. Instead we used the classical technology of uranium bars and water cooling, building more than 40 reactors that are not safe and a nightmare to dismantle.
The reason ? None.

And it's safely providing power to most French homes.

[Isilanka]

You know the funny thing ?
France, the most nuclear-fission reliant country in the world, could have used sodium cooling reactors from the get-go. Instead we used the classical technology of uranium bars and water cooling, building more than 40 reactors that are not safe and a nightmare to dismantle.
The reason ? None.

And it's safely providing power to most French homes.

I know I'm currently using my computer thanks to a lovely little nuclear plant 30 kms away from home.
There's no denying, however, that our nuclear fission industry is currently in one hell of a mess. The amount of delays and overral stupid decisions on the new EPR that's under construction is just insane for such an expensive and crucial project.
Hell, Areva just postponed the entire project for two more years because they can't build a decent cooling system that doesn't leak.

Trust me, our relationship with nuclear fission in France is weird. On the one hand we pride ourselves of having the safest, most extensive nuclear fission network in the world and on the other said nuclear fission is handled by two semi-incompetent, barely controlled companies that haven't been able to achieve anything meaningful since the late 1990s. It's weird. We're treating our plants like some kind of non-important, minor industry.

[Petrolheadia]

And it's safely providing power to most French homes.

I know I'm currently using my computer thanks to a lovely little nuclear plant 30 kms away from home.
There's no denying, however, that our nuclear fission industry is currently in one hell of a mess. The amount of delays and overral stupid decisions on the new EPR that's under construction is just insane for such an expensive and crucial project.
Hell, Areva just postponed the entire project for two more years because they can't build a decent cooling system that doesn't leak.

Trust me, our relationship with nuclear fission in France is weird. On the one hand we pride ourselves of having the safest, most extensive nuclear fission network in the world and on the other said nuclear fission is handled by two semi-incompetent, barely controlled companies that haven't been able to achieve anything meaningful since the late 1990s.

If it's stupid, but it works, it ain't stupid.

[Isilanka]

I know I'm currently using my computer thanks to a lovely little nuclear plant 30 kms away from home.
There's no denying, however, that our nuclear fission industry is currently in one hell of a mess. The amount of delays and overral stupid decisions on the new EPR that's under construction is just insane for such an expensive and crucial project.
Hell, Areva just postponed the entire project for two more years because they can't build a decent cooling system that doesn't leak.

Trust me, our relationship with nuclear fission in France is weird. On the one hand we pride ourselves of having the safest, most extensive nuclear fission network in the world and on the other said nuclear fission is handled by two semi-incompetent, barely controlled companies that haven't been able to achieve anything meaningful since the late 1990s.

If it's stupid, but it works, it ain't stupid.

The thing is it doesn't work. We have several plants reaching the end of their operational lives without any idea how to even begin to dismantle them, the EPR is a goddamn mess ; every year the ASN (Autorité de Sûreté Nucléaire - a public instution that surveys nuclear plants) points out a myriad of security problems in our nuclear plants and every year EDF and Areva essentially answer that they'll solve evrything the next year.
So far it works. But it's far from being a safe and sane industrial domain.

I mean I'm not even talking about the risks of nuclear accident. Our nuclear plants provide 70% of our electricity, we can have nationwide shortages if only five or six plants must be stopped for maintenance at the same time, and with the average French nuclear plant nearing 30 to 40 years old, it's almost bound to happen at one time.

As a whole, we've been sweeping the nuclear fission question under the carpet, collectively, and it's going to bit us in the ass sooner or later.

[Kalaron]

You know the funny thing ?
France, the most nuclear-fission reliant country in the world, could have used sodium cooling reactors from the get-go. Instead we used the classical technology of uranium bars and water cooling, building more than 40 reactors that are not safe and a nightmare to dismantle.
The reason ? None.

Well, the primary reason is probably that Sodium is a bitch to handle, a massive one. If it's reactive at base (and it really, really is) then heating it up to 1700K doesn't help at all. Besides, you'd still be using uranium either way...just hopefully with reprocessing instead of just slapping it somewhere.

[Isilanka]

You know the funny thing ?
France, the most nuclear-fission reliant country in the world, could have used sodium cooling reactors from the get-go. Instead we used the classical technology of uranium bars and water cooling, building more than 40 reactors that are not safe and a nightmare to dismantle.
The reason ? None.

Well, the primary reason is probably that Sodium is a bitch to handle, a massive one. If it's reactive at base (and it really, really is) then heating it up to 1700K doesn't help at all. Besides, you'd still be using uranium either way...just hopefully with reprocessing instead of just slapping it somewhere.

That would still be better than the French approach of "we have a potential problem ? Let's forget about it and hope we have a solution in 40 years" that's been plaguing our nuclear industry, especially in the department of nuclear waste.

[Kalaron]

Well, the primary reason is probably that Sodium is a bitch to handle, a massive one. If it's reactive at base (and it really, really is) then heating it up to 1700K doesn't help at all. Besides, you'd still be using uranium either way...just hopefully with reprocessing instead of just slapping it somewhere.

That would still be better than the French approach of "we have a potential problem ? Let's forget about it and hope we have a solution in 40 years" that's been plaguing our nuclear industry, especially in the department of nuclear waste.

Yeah, a big problem in the US right now is the bias against nuclear reactors that at least partially comes from over-hyped fears about nuclear energy in general and the (bigger issue) of a lack of scientific literacy. Both countries really need to start fixing these issues rather than sweeping them away.

[Constitutional Technocracy of Minecraft]

1. I misunderstood what you meant by NTR in my last post. However, a nuclear thermal rocket has crappy thrust and specific impulse (if you don't play KSP, this is a measure of the efficiency of a rocket engine) within the atmosphere
2. This is designed for crewed missions to Mars, not Titan. Did you read the Wikipedia link!?
3. SpaceX plans to launch each BFR into low Earth orbit, launch a tanker to refuel it and then return to Earth, and send the other ship to Mars after being refuelled. Uncrewed cargo missions will also be sent to Mars to assemble a propellant plant on Mars that will make fuel via ISRU, so the ship can be refuelled on Mars for a direct flight back to Earth (possible due to Mars' lower gravity than Earth). Therefore, they don't need to carry additional fuel for returning.
4. Mars is closer than Titan, and a round trip may take up to 2 years

On the matter of NTRs: It's less a matter of firing the engine in atmosphere, and more a matter of needing to carry less crap up on a booster. For every kilogram of weight (including the dead propellant of your rocket) you need at least three and a half kilograms of active propellant (it's a good rule of thumb) to get it to orbit from the surface. As such, carrying a monumentally better engine up is going to be much, much better than having to carry more yet more fuel up.

For the other points, I thought you were trying to say they'd use it -or could use it- to bring fuel back from Titan like the base post was about, sorry
That said, the sheer ridiculous nature of their "shuttle" claim makes the whole thing reeks of the same technophilia as the Hyperloop, and the promise of bootstrapping a propellant plant has always been a long shot to me. However, Mars is a much closer target, so I'll wait to see whether the BFR is more of a Hyperloop or a Falcon.

1. SpaceX has already bought around 450 acres of land in Los Angeles Harbour to build the factory where BFR will be manufactured, and Elon Musk has tweeted a picture of a massive filament winder which will be used to make the carbon composite hull sections for BFR.
2. The BFR spaceship, like the booster, will be built to land back on Earth, therefore it will need atmospheric engines. However, NTRs may work as vacuum engines.
3. BFR will run on methane propellant. The propellant plant on Mars will make methane and oxidiser from carbon dioxide (extracted form the Martian atmosphere) and hydrogen (made though extraction and electrolysis of subsurface ice) via the Sabatier process.

[Isilanka]

That would still be better than the French approach of "we have a potential problem ? Let's forget about it and hope we have a solution in 40 years" that's been plaguing our nuclear industry, especially in the department of nuclear waste.

Yeah, a big problem in the US right now is the bias against nuclear reactors that at least partially comes from over-hyped fears about nuclear energy in general and the (bigger issue) of a lack of scientific literacy. Both countries really need to start fixing these issues rather than sweeping them away.

Agreed.
In France there's also the problem that you can't have any meaningful discussion about nuclear energy.
Either you're seen as a violent opponent who thinks we should all get back to the middle ages or you're seen as a blind supporter of nuclear fission who ignores all of its (numerous) problems. Then there's also an issue that's very specifically French, I guess, which is our system of "grandes écoles" (essentially, more prestigious universities for the educated elites) has created a litteral caste of governmental engineers who since 40 years have essentially been managing French nuclear fission, both in the public and private sector, without allowing this matter to really exist in any way in the public debate. So we simply don't care about our plants...even if they are going to become a real issue sooner or later and we won't have any political and intellectial tool to actually discuss the new nuclear fission policies when it happens.

[Hurdergaryp]

The problem with oil depletion isn't energy. Finding other sources would be difficult, but not impossible.

The real problem would lie with replacing all the chemicals derived from oil. Plastics, etc. It'd be a nightmare and could easily lead to a protracted global recession.

Alternatives for plastics can be created from vegetable sources these days. Also this is another good reason to start cleaning up the gargantuan amounts of plastic floating around and converging in the oceans, so it can be recycled.

[Constitutional Technocracy of Minecraft]

The problem with oil depletion isn't energy. Finding other sources would be difficult, but not impossible.

The real problem would lie with replacing all the chemicals derived from oil. Plastics, etc. It'd be a nightmare and could easily lead to a protracted global recession.

Alternatives for plastics can be created from vegetable sources these days. Also this is another good reason to start cleaning up the gargantuan amounts of plastic floating around and converging in the oceans, so it can be recycled.

The real problem is the environmental effects of burning fossil fuels. Global warming, rising sea levels, frequent hurricanes, droughts and heatwaves, extinction of species fucking up the biosphere, massive displacement and an unparalleled refugee crisis, etc.

[Kalaron]

On the matter of NTRs: It's less a matter of firing the engine in atmosphere, and more a matter of needing to carry less crap up on a booster. For every kilogram of weight (including the dead propellant of your rocket) you need at least three and a half kilograms of active propellant (it's a good rule of thumb) to get it to orbit from the surface. As such, carrying a monumentally better engine up is going to be much, much better than having to carry more yet more fuel up.

For the other points, I thought you were trying to say they'd use it -or could use it- to bring fuel back from Titan like the base post was about, sorry
That said, the sheer ridiculous nature of their "shuttle" claim makes the whole thing reeks of the same technophilia as the Hyperloop, and the promise of bootstrapping a propellant plant has always been a long shot to me. However, Mars is a much closer target, so I'll wait to see whether the BFR is more of a Hyperloop or a Falcon.

1. SpaceX has already bought around 450 acres of land in Los Angeles Harbour to build the factory where BFR will be manufactured, and Elon Musk has tweeted a picture of a massive filament winder which will be used to make the carbon composite hull sections for BFR.
2. The BFR spaceship, like the booster, will be built to land back on Earth, therefore it will need atmospheric engines. However, NTRs may work as vacuum engines.
3. BFR will run on methane propellant. The propellant plant on Mars will make methane and oxidiser from carbon dioxide (extracted form the Martian atmosphere) and hydrogen (made though extraction and electrolysis of subsurface ice) via the Sabatier process.

Number one means nothing. They took pictures with the steel that would have been meant for the pipes, and a test track was laid down. The efficacy of his action -and the capability of it to do anything- are wholly separate from showing that they made "something" tbh.

Number two, they aren't using NTRs because -as my original comment was- they can't get clearance to do so. Discounting the problem of the Outer Space Treaty, they'll need to get at least American (and more likely, everyone's) permission to launch the mission with any number of rockets like that. Of course, the inclusion of "atmospheric engines" is also pretty terrible since that means you have dead-weight (or close enough to it) for the majority of your trip. As the first links I sent you talked about, the mass ratio of the ship starts to suffer when you include things like that, and you start to lose Delta-V as a result. Here was a good video by Thunderfoot ripping into the BFR for it's whole "Shuttle" nonsense, but it does apply quite a bit for rocketry in general. https://www.youtube.com/watch?v=j4KR4-TN-Yo

Number three, bootstrapping is the primary issue and hence my mention of it. The science isn't an issue there because it's simple chemistry and resource handling, but doing so in an automated way is a harder task than I think you realize.

[Hurdergaryp]

Alternatives for plastics can be created from vegetable sources these days. Also this is another good reason to start cleaning up the gargantuan amounts of plastic floating around and converging in the oceans, so it can be recycled.

The real problem is the environmental effects of burning fossil fuels. Global warming, rising sea levels, frequent hurricanes, droughts and heatwaves, extinction of species fucking up the biosphere, massive displacement and an unparalleled refugee crisis, etc.

This is why cars with electrical engines and hydrogen fuel cell vehicles are gradually becoming more common in traffic, at least in urban areas. There are a multitude of reasons to make us less dependent on fossil fuels, environmental as well as geopolitical.

[Constitutional Technocracy of Minecraft]

1. SpaceX has already bought around 450 acres of land in Los Angeles Harbour to build the factory where BFR will be manufactured, and Elon Musk has tweeted a picture of a massive filament winder which will be used to make the carbon composite hull sections for BFR.
2. The BFR spaceship, like the booster, will be built to land back on Earth, therefore it will need atmospheric engines. However, NTRs may work as vacuum engines.
3. BFR will run on methane propellant. The propellant plant on Mars will make methane and oxidiser from carbon dioxide (extracted form the Martian atmosphere) and hydrogen (made though extraction and electrolysis of subsurface ice) via the Sabatier process.

Number one means nothing. They took pictures with the steel that would have been meant for the pipes, and a test track was laid down. The efficacy of his action -and the capability of it to do anything- are wholly separate from showing that they made "something" tbh.

Number two, they aren't using NTRs because -as my original comment was- they can't get clearance to do so. Discounting the problem of the Outer Space Treaty, they'll need to get at least American (and more likely, everyone's) permission to launch the mission with any number of rockets like that. Of course, the inclusion of "atmospheric engines" is also pretty terrible since that means you have dead-weight (or close enough to it) for the majority of your trip. As the first links I sent you talked about, the mass ratio of the ship starts to suffer when you include things like that, and you start to lose Delta-V as a result. Here was a good video by Thunderfoot ripping into the BFR for it's whole "Shuttle" nonsense, but it does apply quite a bit for rocketry in general. https://www.youtube.com/watch?v=j4KR4-TN-Yo

Number three, bootstrapping is the primary issue and hence my mention of it. The science isn't an issue there because it's simple chemistry and resource handling, but doing so in an automated way is a harder task than I think you realize.

1. OK. That doesn't change the size of SpaceX's development budget, which is all being put towards BFR.

2. Inclusion of atmospheric engines is necessary for high thrust and specific impulse within a planet's atmosphere (and BFR will have to land back on Earth). The nozzle of a rocket engine has to be in the correct shape for the static pressure inside the engine to be equal to the ambient pressure for maximum efficiency, otherwise the exhaust will be squeezed inwards or will expand outwards, reducing efficiency. Here's an image showing the four expansion regimes of a rocket nozzle (the first is where the ambient pressure is too low, the second is perfect, the third and fourth have too high an ambient pressure):



Here's a video by Curious Elephant on why SpaceX should not add nuclear thermal engines to BFR

3. How is automating some air pumps (to extract carbon dioxide from the Martian atmosphere), subsurface drills (to extract subsurface ice), an electrolysis cell, a high-pressure heated reaction chamber, and some fuel pumps (to pump the fuel into BFRs) a difficult task?

[UniversalCommons]

Oil can be replaced with something called a biorefinery. There are a number of feedstocks which can go into a biorefinery to produce a variety of different goods. A good example of a company that refines wheat into feedstocks is MGP Ingredients, they make alcohol, ethanol, and food products from wheat. There are a number of different biomass feedstocks-- algae, yard waste, animal waste, which can be used.

There is contention that Brazil could gain 20 more biorefineries if US energy policies changed. There are already 3 major biorefineries in Brazil. There has been a large scale on refinement of sugarcane into Ethanol in Brazil. http://www.abbi.org.br/pt/noticia/brazi ... in-policy/ It would be better if we ate less sugar and instead turned it into fuel.

With Ethanol most cars can take a 10% mix, a lot of cars are Flexible Fuel Vehicles. When the diesel engine was first invented, it could run on peanut oil. It is very easy to convert diesel engines to biodiesel. Most diesel engines can run on straight biodiesel. Also, turbine engines can be designed to run on almost any fuel that can be burned.

Hyridization with electricity increases the range of biofuels. There are a lot more options than people realize.

[Kalaron]

Number one means nothing. They took pictures with the steel that would have been meant for the pipes, and a test track was laid down. The efficacy of his action -and the capability of it to do anything- are wholly separate from showing that they made "something" tbh.

Number two, they aren't using NTRs because -as my original comment was- they can't get clearance to do so. Discounting the problem of the Outer Space Treaty, they'll need to get at least American (and more likely, everyone's) permission to launch the mission with any number of rockets like that. Of course, the inclusion of "atmospheric engines" is also pretty terrible since that means you have dead-weight (or close enough to it) for the majority of your trip. As the first links I sent you talked about, the mass ratio of the ship starts to suffer when you include things like that, and you start to lose Delta-V as a result. Here was a good video by Thunderfoot ripping into the BFR for it's whole "Shuttle" nonsense, but it does apply quite a bit for rocketry in general. https://www.youtube.com/watch?v=j4KR4-TN-Yo

Number three, bootstrapping is the primary issue and hence my mention of it. The science isn't an issue there because it's simple chemistry and resource handling, but doing so in an automated way is a harder task than I think you realize.

1. OK. That doesn't change the size of SpaceX's development budget, which is all being put towards BFR.

2. Inclusion of atmospheric engines is necessary for high thrust and specific impulse within a planet's atmosphere (and BFR will have to land back on Earth). The nozzle of a rocket engine has to be in the correct shape for the static pressure inside the engine to be equal to the ambient pressure for maximum efficiency, otherwise the exhaust will be squeezed inwards or will expand outwards, reducing efficiency. Here's an image showing the four expansion regimes of a rocket nozzle (the first is where the ambient pressure is too low, the second is perfect, the third and fourth have too high an ambient pressure):



Here's a video by Curious Elephant on why SpaceX should not add nuclear thermal engines to BFR

3. How is automating some air pumps (to extract carbon dioxide from the Martian atmosphere), subsurface drills (to extract subsurface ice), an electrolysis cell, a high-pressure heated reaction chamber, and some fuel pumps (to pump the fuel into BFRs) a difficult task?

1) Nor did it change the fact that the Hyperloop had a significant amount of money thrown at it. There were literal competitions for it hosted by Elon. Didn't change the fact that the material science behind it is dumb, or the fact that it wouldn't work under ideal conditions. And honestly? Budget means nothing to capability until the actual rocket performance is recorded. Budget is ultimately the upper limit while execution is the lower limit. I would also like to note that ignoring Elon's insanity on one part of the claim is a bit silly, need I point out that he also said that he'll sell shuttle tickets for the price of regular airfare?
Elon is a very good showman, but he's a poor scientist, all things considered.

2) Which is why landing with such a large rocket is frankly stupid. A better method would be to have a smaller, specialized ship come up to fuel it and/or retrieve the people and equipment from it while it continues to orbit. There is frankly no need for it to land on earth (though frankly I also have problems with landing a rocket bigger than the Saturn V booster on unprepared ground when it comes to mars) considering the sheer cost of such, and the frank unproven utility of reusing them (We ironically had the same debate some decades ago, it was called the space shuttle and the cost savings were not really there)
The video, as well, is wrong on several fronts: first, nuclear engines are not a block. Their "low thrust to weight" really shouldn't be grouped together because the DUMBO engine achieved a 71 odd thrust to weight ratio only marginally worse than one of the F1 engines for the Saturn (86.206), and better than the SSME for the space shuttle (58.313). This ignores DUMBO model B which had a T/W of 130. It also suffers from not mentioning the real problem of building a NTR, that is, the rights to do so would be bowled down into political fights. Of course, again, landing the rocket is still an issue and requires a whole host of complexities to an already dangerous regime of engines operating in extreme conditions where eliminating failure prone mechanisms (Cough, gimbals, cough) is a beloved action and adding more in is a source of despair. That said, at least the video itself admitted that he was just giving his opinion rather than noting any real problem about the engines. And I'm still certain that the rocket doesn't like the dead mass added on? Adding engines that you won't use for the majority of the trip is a bad thing for a lot of reasons, but the sheer dead weight is a significant one that bites into the mass ratio like a wolf.

3) Because Mars is only slightly friendlier than space itself. You have uneven terrain, scouring winds and burrowing sand, placement issues for the actual technology, potential coding issues and a host of other problems that could completely derail the plant itself.

[Constitutional Technocracy of Minecraft]

1. OK. That doesn't change the size of SpaceX's development budget, which is all being put towards BFR.

2. Inclusion of atmospheric engines is necessary for high thrust and specific impulse within a planet's atmosphere (and BFR will have to land back on Earth). The nozzle of a rocket engine has to be in the correct shape for the static pressure inside the engine to be equal to the ambient pressure for maximum efficiency, otherwise the exhaust will be squeezed inwards or will expand outwards, reducing efficiency. Here's an image showing the four expansion regimes of a rocket nozzle (the first is where the ambient pressure is too low, the second is perfect, the third and fourth have too high an ambient pressure):



Here's a video by Curious Elephant on why SpaceX should not add nuclear thermal engines to BFR

3. How is automating some air pumps (to extract carbon dioxide from the Martian atmosphere), subsurface drills (to extract subsurface ice), an electrolysis cell, a high-pressure heated reaction chamber, and some fuel pumps (to pump the fuel into BFRs) a difficult task?

1) Nor did it change the fact that the Hyperloop had a significant amount of money thrown at it. There were literal competitions for it hosted by Elon. Didn't change the fact that the material science behind it is dumb, or the fact that it wouldn't work under ideal conditions. And honestly? Budget means nothing to capability until the actual rocket performance is recorded. Budget is ultimately the upper limit while execution is the lower limit. I would also like to note that ignoring Elon's insanity on one part of the claim is a bit silly, need I point out that he also said that he'll sell shuttle tickets for the price of regular airfare?
Elon is a very good showman, but he's a poor scientist, all things considered.

2) Which is why landing with such a large rocket is frankly stupid. A better method would be to have a smaller, specialized ship come up to fuel it and/or retrieve the people and equipment from it while it continues to orbit. There is frankly no need for it to land on earth (though frankly I also have problems with landing a rocket bigger than the Saturn V booster on unprepared ground when it comes to mars) considering the sheer cost of such, and the frank unproven utility of reusing them (We ironically had the same debate some decades ago, it was called the space shuttle and the cost savings were not really there)
The video, as well, is wrong on several fronts: first, nuclear engines are not a block. Their "low thrust to weight" really shouldn't be grouped together because the DUMBO engine achieved a 71 odd thrust to weight ratio only marginally worse than one of the F1 engines for the Saturn (86.206), and better than the SSME for the space shuttle (58.313). This ignores DUMBO model B which had a T/W of 130. It also suffers from not mentioning the real problem of building a NTR, that is, the rights to do so would be bowled down into political fights. Of course, again, landing the rocket is still an issue and requires a whole host of complexities to an already dangerous regime of engines operating in extreme conditions where eliminating failure prone mechanisms (Cough, gimbals, cough) is a beloved action and adding more in is a source of despair. That said, at least the video itself admitted that he was just giving his opinion rather than noting any real problem about the engines. And I'm still certain that the rocket doesn't like the dead mass added on? Adding engines that you won't use for the majority of the trip is a bad thing for a lot of reasons, but the sheer dead weight is a significant one that bites into the mass ratio like a wolf.

3) Because Mars is only slightly friendlier than space itself. You have uneven terrain, scouring winds and burrowing sand, placement issues for the actual technology, potential coding issues and a host of other problems that could completely derail the plant itself.

1. 5 years ago people were saying that Falcon 9's reusability was impossible. Now Falcon 9 boosters routinely land without making any headlines. I'm unsure about the feasibility of BFR for transcontinental flights, though.
2. Landing a BFR spaceship on unprepared Martian ground would not be a problem, as Mars has a rocky, hard surface - the only concern would be dark, ugly engine marks on the terrain (and no one gives a shit about natural beauty of BFR landing sites) The space shuttle cost so much due to the complexity of its engines, and SpaceX's Merlin (used on F9/FH) and Raptor (will be used on BFR) engines are much cheaper to manufacture and maintain. Nuclear engines have such a low thrust-to-weight ratio that the ship wouldn't be able to lift its own weight and would smash into the ground on landing. Saying that atmospheric engines will not be used "for the majority of the trip" is a misnomer since the ship will spend most of its flight time with its engines off during interplanetary coasting - a better reason would be "contributes very little delta-v change".
3. Martian rovers already work in Martian conditions without humans within tens of millions of kilometres. Coding issues can be picked up by coding software nowadays so you don't get Mariner 1-style errors. Also, note that the propellant plant is planned to operate right next to a fucking crewed Mars base.

[Christmas Pudding]

Oil can be replaced with something called a biorefinery. There are a number of feedstocks which can go into a biorefinery to produce a variety of different goods. A good example of a company that refines wheat into feedstocks is MGP Ingredients, they make alcohol, ethanol, and food products from wheat. There are a number of different biomass feedstocks-- algae, yard waste, animal waste, which can be used.

There is contention that Brazil could gain 20 more biorefineries if US energy policies changed. There are already 3 major biorefineries in Brazil. There has been a large scale on refinement of sugarcane into Ethanol in Brazil. http://www.abbi.org.br/pt/noticia/brazi ... in-policy/ It would be better if we ate less sugar and instead turned it into fuel.

With Ethanol most cars can take a 10% mix, a lot of cars are Flexible Fuel Vehicles. When the diesel engine was first invented, it could run on peanut oil. It is very easy to convert diesel engines to biodiesel. Most diesel engines can run on straight biodiesel. Also, turbine engines can be designed to run on almost any fuel that can be burned.

Hyridization with electricity increases the range of biofuels. There are a lot more options than people realize.

What sorts of petrochemicals can be made with biofuel? Are there any limits there? Forgive my ignorance, I don't know a ton about the subject.

[UniversalCommons]

Oil can be replaced with something called a biorefinery. There are a number of feedstocks which can go into a biorefinery to produce a variety of different goods. A good example of a company that refines wheat into feedstocks is MGP Ingredients, they make alcohol, ethanol, and food products from wheat. There are a number of different biomass feedstocks-- algae, yard waste, animal waste, which can be used.

There is contention that Brazil could gain 20 more biorefineries if US energy policies changed. There are already 3 major biorefineries in Brazil. There has been a large scale on refinement of sugarcane into Ethanol in Brazil. http://www.abbi.org.br/pt/noticia/brazi ... in-policy/ It would be better if we ate less sugar and instead turned it into fuel.

With Ethanol most cars can take a 10% mix, a lot of cars are Flexible Fuel Vehicles. When the diesel engine was first invented, it could run on peanut oil. It is very easy to convert diesel engines to biodiesel. Most diesel engines can run on straight biodiesel. Also, turbine engines can be designed to run on almost any fuel that can be burned.

Hyridization with electricity increases the range of biofuels. There are a lot more options than people realize.

What sorts of petrochemicals can be made with biofuel? Are there any limits there? Forgive my ignorance, I don't know a ton about the subject.

Biodiesel can be produced which is similar to diesel. There is also ethanol from corn, methane from animal waste, cellulosic ethanol is a possibility from lignin in plants, algae oil from algae-- there is a derivative of algae oil that can be used as jet fuel, you can make and burn compressed pellets from wood and other forest materials-- this is increasingly being used in cofiring coal plants to reduce emissions, there is also bio-butanol, and biogas. The variety of feedstocks varies tremendously from palm oil to sugar cane to processed landfill mass. A lot of this is about research into which sources produce the most efficient fuels. None of them match oil because oil is essentially concentrated dead material which has stayed under the ground for hundreds of thousands of years. They are not petrochemicals, but plant derived chemicals. The goal for example with corn in a corn biorefinery would be to make ethanol, drinking alcohol, corn based plastics, animal feed, and other products.

One of the problems with the US nuclear industry is a refusal to reprocess spent nuclear fuel. Also, the designs are not up to date.
https://archive.nytimes.com/www.nytimes ... wanted=all

People like the idea of nuclear power until it is put right next to you. Then it becomes scary. No matter how safe people tell you that nuclear power is, it is fearsome.

[Kanadorika]

We will run out of oil, that isn't even a question.

It will collapse nations.

Invest in fusion boi.

Do we even have a viable fusion plant?

Not yet, though we may soon have something even better

Fusion reactors that can fit on a truck and power a city of 100,000.

[Stroulia]

Oil will eventually run dry, that's just an inevitability. The real question is when, and what happens when we reach that point?

Assuming that we do continue on as a species and society to that point, the ideal situation is that we'll have developed alternate fuel sources to the point where fossil fuels are either the minority fuel source or have been entirely phased out. However, in a worst-case scenario, we're seeing the total collapse of nations that are dependent on their fuel supplies, such as Venezuela and Saudi Arabia. I wouldn't be surprised if the search for remaining oil led to open conflict over it.