Jay
Bork! Bork! Bork!
+2,006|5359|London, England

Flaming_Maniac wrote:

http://en.wikipedia.org/wiki/Nuclear_thermal_rocket

oh lol, this is ONLY good for an upper stage
One of the benefits to attending a college where the emphasis is on marine engineering and seamanship is that I've had a lot of contact with steam turbines. Mock it if you want, but there is a tremendous amount of force generated by superheated gases. A nozzled release of superheated hydrogen would be far more than enough to propel a rocket from standing into orbit.
"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat
Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85

JohnG@lt wrote:

it also diminishes the chance of an explosion to near zero. Me likey.
...no, it doesn't, the chance of a failure is the same as with nuclear pulse engines

Berster I see that you are right but I am still reading

I know you can get plenty of force from pressure, I mis-read something in the wiki article.

I would still like to see a performance side by side with nuclear pulse. For long distance travel that still seems to make more sense.
Bertster7
Confused Pothead
+1,101|6583|SE London

Flaming_Maniac wrote:

JohnG@lt wrote:

it also diminishes the chance of an explosion to near zero. Me likey.
...no, it doesn't, the chance of a failure is the same as with nuclear pulse engines

Berster I see that you are right but I am still reading

I know you can get plenty of force from pressure, I mis-read something in the wiki article.

I would still like to see a performance side by side with nuclear pulse. For long distance travel that still seems to make more sense.
Well you can't because nuclear pulse technology is purely theoretical. As far as I'm aware they have never built any prototypes for testing. Whereas the NERVA rocket was tested very successfully.

Nuclear pulse technology is not considered a serious option for the foreseeable future. In 2005 and 2007 (which is while I was studying this in an optional course at uni and taking quite an interest in this - hence me not having to rely on frantically reading wiki articles) NASA were again considering using an updated version of the NERVA rocket. With modern nuclear fuels they predict they could have about 20% more power and nano engineered casings could allow for longer sustained burntimes.

Also - your point about the chance of failure being the same as with nuclear pulse engines is not accurate. I'd missed that bit. It's way, way safer. It releases virtually no radiation. It has a much smaller nuclear payload. There is simply far less to go wrong. Exploding nuclear bombs behind you in an attempt to make you go faster is much, much riskier than passing hydrogen fuel directly through a small scale fission reactor and ejecting the superheated hydrogen behind you.

Last edited by Bertster7 (2010-08-15 13:00:27)

Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85
Nuclear pulse is not being considered because there isn't a mission that even remotely warrants it on the docket. If there was a legitimate push to put a man on Mars, you bet your ass it would be seriously considered.

Nuclear pulse has ridiculous fuel density and performance, but is bulky and not suitable for putting things in orbit. Nuclear thermal is really just a higher performing chemical rocket. Saying one is better because it has been built and tested makes little sense when one clearly meets current needs the other doesn't. It's not as if the technology behind nuclear pulse isn't there.
Bertster7
Confused Pothead
+1,101|6583|SE London

Flaming_Maniac wrote:

Nuclear pulse is not being considered because there isn't a mission that even remotely warrants it on the docket. If there was a legitimate push to put a man on Mars, you bet your ass it would be seriously considered.

Nuclear pulse has ridiculous fuel density and performance, but is bulky and not suitable for putting things in orbit. Nuclear thermal is really just a higher performing chemical rocket. Saying one is better because it has been built and tested makes little sense when one clearly meets current needs the other doesn't. It's not as if the technology behind nuclear pulse isn't there.
It isn't.

Nuclear pulse is insane. You also need vast spacecraft to use nuclear pulse technology.

A higher performing chemical type rocket is what is needed. It's for practical and realistic applications. For a mission to Mars, nuclear thermal would be far, far more likely to be used - which is what it was originally designed to do. Using a NERVA based system would cut 100-130 days from the length of the journey to Mars compared to a chemical rocket. It's perfect for it.

Nuclear pulse becomes a viable option only when looking at travel that would otherwise be unthinkable - such as travelling to other stars.
Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85
uh

Nuclear pulse is insane...why?
Jay
Bork! Bork! Bork!
+2,006|5359|London, England

Flaming_Maniac wrote:

uh

Nuclear pulse is insane...why?
Because there is no need to release radiation into the atmosphere.

If you are talking about it from a pure efficiency standpoint, sure, pulse is better. If you are talking about it in a realistic fashion where the side effects actually matter, pulse is indeed insane.
"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat
Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85
Dude, read the thread, I have been arguing for pages against using nuclear pulse rockets in the atmosphere.

Nuclear pulse rockets in space however make a lot of sense.
Bertster7
Confused Pothead
+1,101|6583|SE London

Flaming_Maniac wrote:

uh

Nuclear pulse is insane...why?
Because surfing the shockwave of nuclear explosions in insane. That's what nuclear pulse technology is.
Jay
Bork! Bork! Bork!
+2,006|5359|London, England

Flaming_Maniac wrote:

Dude, read the thread, I have been arguing for pages against using nuclear pulse rockets in the atmosphere.

Nuclear pulse rockets in space however make a lot of sense.
They do, but why bother? As Berster said, there is no need unless you're talking about an insane distance like reaching another star. What happens when you reach your destination and it's time to come home? You've now irradiated the area to the point that it is uninhabitable if you wish to ever return.
"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat
Jay
Bork! Bork! Bork!
+2,006|5359|London, England
Btw, I'm reminded of these toys from my childhood:

https://ecx.images-amazon.com/images/I/41495KKMT7L._SL500_AA300_.jpg

"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat
Bertster7
Confused Pothead
+1,101|6583|SE London

Flaming_Maniac wrote:

Dude, read the thread, I have been arguing for pages against using nuclear pulse rockets in the atmosphere.

Nuclear pulse rockets in space however make a lot of sense.
How do you get the vast quantities of nuclear material required into space?

The transport of that material into space would be riskier by far than actually using a NERVA rocket - purely because of the quantities of radioactive material involved.
presidentsheep
Back to the Fuhrer
+208|5963|Places 'n such

JohnG@lt wrote:

Btw, I'm reminded of these toys from my childhood:

http://ecx.images-amazon.com/images/I/4 … AA300_.jpg

Good point, i'm sure say... The population of china/russia/usa could produce enough thrust to reach somewhere?
I'd type my pc specs out all fancy again but teh mods would remove it. Again.
Jay
Bork! Bork! Bork!
+2,006|5359|London, England

presidentsheep wrote:

JohnG@lt wrote:

Btw, I'm reminded of these toys from my childhood:

http://ecx.images-amazon.com/images/I/4 … AA300_.jpg

Good point, i'm sure say... The population of china/russia/usa could produce enough thrust to reach somewhere?
Hamster wheels or bicycles?
"Ah, you miserable creatures! You who think that you are so great! You who judge humanity to be so small! You who wish to reform everything! Why don't you reform yourselves? That task would be sufficient enough."
-Frederick Bastiat
Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85

Bertster7 wrote:

Flaming_Maniac wrote:

uh

Nuclear pulse is insane...why?
Because surfing the shockwave of nuclear explosions in insane. That's what nuclear pulse technology is.
Why is it insane. You are just saying it's crazy as if that is an explanation.

JohnG@lt wrote:

Flaming_Maniac wrote:

Dude, read the thread, I have been arguing for pages against using nuclear pulse rockets in the atmosphere.

Nuclear pulse rockets in space however make a lot of sense.
They do, but why bother? As Berster said, there is no need unless you're talking about an insane distance like reaching another star. What happens when you reach your destination and it's time to come home? You've now irradiated the area to the point that it is uninhabitable if you wish to ever return.
An insane distance is going to Mars or a moon of Jupiter, not just another star.

Bertster7 wrote:

Flaming_Maniac wrote:

Dude, read the thread, I have been arguing for pages against using nuclear pulse rockets in the atmosphere.

Nuclear pulse rockets in space however make a lot of sense.
How do you get the vast quantities of nuclear material required into space?

The transport of that material into space would be riskier by far than actually using a NERVA rocket - purely because of the quantities of radioactive material involved.
...you move then with a chemical or thermal nuclear shuttle?
Bertster7
Confused Pothead
+1,101|6583|SE London

Flaming_Maniac wrote:

Bertster7 wrote:

The transport of that material into space would be riskier by far than actually using a NERVA rocket - purely because of the quantities of radioactive material involved.
...you move then with a chemical or thermal nuclear shuttle?
Which is more dangerous than using a nuclear thermal rocket. It's also much more complicated and is not something that people will be able to do in a practical or safe way for ages.

I don't understand your crazy warped perspective here. You complain about the dangers and impracticalities of using nuclear rockets and then, when presented with a practical and fairly safe nuclear rocket option that could be built and used right away, you reject it.

Go ahead - demonstrate how safe and easy it is to use nuclear pulse technology (or even explain why you think it could realistically be used any time in the next few decades), which would be contrary to everything I've ever learnt on the subject.

Flaming_Maniac wrote:

Why is it insane. You are just saying it's crazy as if that is an explanation.
I think most people will happily conceed that the whole concept of surfing nuclear shockwaves is insane without any need to elaborate on that. It's like saying flying a deckchair fitted with helium balloons is insane - you can do it, as that bloke did (and got a Darwin award for), but it will probably go horribly wrong.
Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85
"Most people" do and think a lot of stupid things. I am disappointed you think that is an argument.

Moving nuclear material into orbit with a chemical rocket is only marginally more dangerous that a normal mission using a chemical rocket. It is not particularly easy to instigate a nuclear reaction without making an effort, and it is certainly very difficult to accidentally start a nuclear reaction when the payload has been secured against even a catastrophic failure.

I took issue with nuclear pulse rockets in the atmosphere because of the danger to civilians even when the rockets works well. You make the assumption when you say the alternative is more practical and safe that it also performs equally as well. This is simply not true.

The nozzle velocity of a chemical rocket is about 2.5 km/s (http://en.wikipedia.org/wiki/Specific_impulse), and thermal nuclear rockets are double that or more (http://en.wikipedia.org/wiki/Nuclear_thermal_rocket). So we're talking ballpark of 5 km/s. Nuclear pulse rockets are on the order of 20-30 km/s (http://en.wikipedia.org/wiki/Project_Or … pulsion%29). NERVA derivative rockets have a thrust on the order of .11 meganewtons (http://wapedia.mobi/en/Nuclear_thermal_rocket), and nuclear pulse rockets are in the meganewtons (http://en.wikipedia.org/wiki/Project_Or … pulsion%29 [from a source from the 1960s]).

I don't understand why you think it isn't safe or easy to use. The design is incredibly simple. You explode a really big bomb, probably behind the spaceship, that is absorbed in a really big pusher plate. Radiation is not an issue in space. Ablation is not an issue, as apparently when you spray down the surface with oil it prevents that problem. There are risks if any number of the parts of the system do not work properly - as with any sort of space vessel. You're going to have to explain exactly what is so insane about it.

http://en.wikipedia.org/wiki/Project_Or … l_problems
Harmor
Error_Name_Not_Found
+605|6550|San Diego, CA, USA
What about a giant (4 mile long), rail gun to shoot stuff into orbit cheaply?
presidentsheep
Back to the Fuhrer
+208|5963|Places 'n such

Harmor wrote:

What about a giant (4 mile long), rail gun to shoot stuff into orbit cheaply?
With something as large as a space shuttle, the heat generated would be huge as would the amount electricity needed to get something that large, that far.

though a gauss gun type thing has been suggested:
http://en.wikipedia.org/wiki/Mass_driver

Last edited by presidentsheep (2010-08-15 16:07:10)

I'd type my pc specs out all fancy again but teh mods would remove it. Again.
Bertster7
Confused Pothead
+1,101|6583|SE London

Flaming_Maniac wrote:

"Most people" do and think a lot of stupid things. I am disappointed you think that is an argument.

Moving nuclear material into orbit with a chemical rocket is only marginally more dangerous that a normal mission using a chemical rocket. It is not particularly easy to instigate a nuclear reaction without making an effort, and it is certainly very difficult to accidentally start a nuclear reaction when the payload has been secured against even a catastrophic failure.

I took issue with nuclear pulse rockets in the atmosphere because of the danger to civilians even when the rockets works well. You make the assumption when you say the alternative is more practical and safe that it also performs equally as well. This is simply not true.

The nozzle velocity of a chemical rocket is about 2.5 km/s (http://en.wikipedia.org/wiki/Specific_impulse), and thermal nuclear rockets are double that or more (http://en.wikipedia.org/wiki/Nuclear_thermal_rocket). So we're talking ballpark of 5 km/s. Nuclear pulse rockets are on the order of 20-30 km/s (http://en.wikipedia.org/wiki/Project_Or … pulsion%29). NERVA derivative rockets have a thrust on the order of .11 meganewtons (http://wapedia.mobi/en/Nuclear_thermal_rocket), and nuclear pulse rockets are in the meganewtons (http://en.wikipedia.org/wiki/Project_Or … pulsion%29 [from a source from the 1960s]).

I don't understand why you think it isn't safe or easy to use. The design is incredibly simple. You explode a really big bomb, probably behind the spaceship, that is absorbed in a really big pusher plate. Radiation is not an issue in space. Ablation is not an issue, as apparently when you spray down the surface with oil it prevents that problem. There are risks if any number of the parts of the system do not work properly - as with any sort of space vessel. You're going to have to explain exactly what is so insane about it.

http://en.wikipedia.org/wiki/Project_Or … l_problems
You don't have an engineering background do you?

It shows.

It's a very simple principle, actually doing it would be incredibly difficult. Whereas NERVA based designs are very complicated in principle, but the application of these principles is easy. The number of things that could go horribly wrong with pulse based designs (not to mention all the other things) makes them impractical.

You really need to start getting your information from somewhere that isn't Wikipedia. It is not a strong scientific source and doesn't show both sides of this picture at all.

Flaming_Maniac wrote:

Moving nuclear material into orbit with a chemical rocket is only marginally more dangerous that a normal mission using a chemical rocket. It is not particularly easy to instigate a nuclear reaction without making an effort, and it is certainly very difficult to accidentally start a nuclear reaction when the payload has been secured against even a catastrophic failure.
This statement really shows you haven't understood the main risk here. It is not from any sort of nuclear reaction - it's from the spacecraft exploding in a catastrophic manner and showering a huge area with radioactive material. Those are the risks of using NERVA based designs and you would have a greater risk transporting the much larger quantities of nuclear material into orbit to fuel a nuclear pulse based craft. It's a much more significant risk because of the volumes of nuclear material involved that could irradiate huge areas. It has already been demonstrated in loads of tests that there is no way to reliably secure a payload against catatrophic failure - if the rocket blows up, the payload is exposed.

It is also impractical to launch such a craft by chemical rocket (since the craft would need to weigh so much), so it would need to be built in orbit or be able to get into orbit under nuclear pulse propulsion - madness. Building something like this in orbit is unrealistic at present.

So:

Immense cost (really, truly, horrifically immense cost - we're talking tens of trillions here).
High risk.
Untested.
Barely possible with existing technology.
Suspected high failure rate (through damage to the pusher plates).

Vs.

Low cost (after a few launches the technology would have paid for itself).
Low risk (low volume of nuclear material carried into orbit the only risk).
Successfully tested.
Easy to implement.
Demonstrated low failure rate (0).

As I said, for the foreseeable future, nuclear pulse technology is not feasible. It is not practical. It is not safe. It is not affordable. It is by no means certain that it would work and if it did work, there is very little evidence to indicate how reliable it would be.

It's the sort of concept that physicists love and engineers loathe - because it's a nice idea in theory, but the practicalities make it unthinkable.

In 100 years time, maybe we could build a nice nuclear pulse powered ship on the Moon which could be used to travel really huge distances. Because huge distances are all it would be worth using it for - it's too stupidly dangerous and expensive for anything else and there are much more sensible alternatives that could be used.

If you seriously think nuclear pulse rockets are something that could be used anytime over the next decade for anything other than a global catastrophy where safety and cost cease to be an issue, then you are mad.
Bertster7
Confused Pothead
+1,101|6583|SE London

Harmor wrote:

What about a giant (4 mile long), rail gun to shoot stuff into orbit cheaply?
We were working on a project like this when I was at uni. We were funded by NASA for it.

Big magnetic track which would accelerate a shuttle up to speed and launch it. We had a prototype we used to fire huge chunks of metal across the lab. It was great fun.

I didn't do any of the design work (that was all done by PhD students), but I did get involved with some of the testing of it. It was going to be much longer than 4 miles. I can't remember how long, but it was more like 50 than 4.



Space systems was one of the most fun courses I did, even more fun than my course in playing with Lego robots.

presidentsheep wrote:

Harmor wrote:

What about a giant (4 mile long), rail gun to shoot stuff into orbit cheaply?
With something as large as a space shuttle, the heat generated would be huge as would the amount electricity needed to get something that large, that far.

though a gauss gun type thing has been suggested:
http://en.wikipedia.org/wiki/Mass_driver
In fact the guy who setup the project at my uni (Sussex) is mentioned in the Wiki article you've linked to - Eric Laithwaite.

Last edited by Bertster7 (2010-08-15 16:51:03)

Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85

Berster7 wrote:

You don't have an engineering background do you?

It shows.

It's a very simple principle, actually doing it would be incredibly difficult. Whereas NERVA based designs are very complicated in principle, but the application of these principles is easy. The number of things that could go horribly wrong with pulse based designs (not to mention all the other things) makes them impractical.

You really need to start getting your information from somewhere that isn't Wikipedia. It is not a strong scientific source and doesn't show both sides of this picture at all.
Hey look, you said nothing here. You attack my credibility, you attack the credibility of sources, you say "the number of things that could go horribly wrong...makes them impractical", and not once did you actually give a reason as to why I am wrong, why my sources are wrong, what exactly could go wrong. Now I haven't finished reading your post but this entire block of text is completely pointless.

Berster7 wrote:

This statement really shows you haven't understood the main risk here. It is not from any sort of nuclear reaction - it's from the spacecraft exploding in a catastrophic manner and showering a huge area with radioactive material. Those are the risks of using NERVA based designs and you would have a greater risk transporting the much larger quantities of nuclear material into orbit to fuel a nuclear pulse based craft. It's a much more significant risk because of the volumes of nuclear material involved that could irradiate huge areas. It has already been demonstrated in loads of tests that there is no way to reliably secure a payload against catatrophic failure - if the rocket blows up, the payload is exposed.
hurr durr that is exactly what I was talking about. I don't know how you missed this, I even used the word payload.

Flaming_Maniac wrote:

It is not particularly easy to instigate a nuclear reaction without making an effort, and it is certainly very difficult to accidentally start a nuclear reaction when the payload has been secured against even a catastrophic failure.
So a) an accidental nuclear reaction even in the event of catastrophic failure is less than unlikely and b) we can build a black box that can secure 1 gram of nuclear material after you assume there is no accidental nuclear reaction. Unless of course you can provide proof that "It has already been demonstrated in loads of tests that there is no way to reliably secure a payload against catatrophic failure"? I mean if it has been demonstrated in loads of tests, why didn't you provide one? If you are willing to bring relatively small loads at a time to build up the stockpile you need over many, many chemical launches the  additional risk is marginal. 1 gram is not a realistic figure, it is a figure to demonstrate my point. The cost of any such nuclear pulse rocket program would be so great that any number of launches to bring parts to be assembled in space, including the fuel, would be completely justified.

Flaming_Maniac wrote:

It is also impractical to launch such a craft by chemical rocket (since the craft would need to weigh so much), so it would need to be built in orbit or be able to get into orbit under nuclear pulse propulsion - madness. Building something like this in orbit is unrealistic at present.
Of course it would be assembled in space. This argument started from me stating that this would obviously be built in space.

Why is it unrealistic? Technologically it's not unrealistic. Given the drive we are perfectly capable of assembling large objects in space. Politically yes, it is unrealistic, but politically any of the missions that this type of technology would be used for is unrealistic. In the current political climate primarily because of the current economic climate going to Mars in the next ten years is completely unrealistic. Going to the moon in the next ten years is unrealistic. Reworking the goddamn shuttle system in the next ten years is unrealistic. But, when we are looking to seriously step up our space exploration, we would be seriously looking into assembling much larger structures in space, be it vessels, planetary bases, stations, whatever.

Berster7 wrote:

So:

Immense cost (really, truly, horrifically immense cost - we're talking tens of trillions here).
High risk.
Untested.
Barely possible with existing technology.
Suspected high failure rate (through damage to the pusher plates).

Vs.

Low cost (after a few launches the technology would have paid for itself).
Low risk (low volume of nuclear material carried into orbit the only risk).
Successfully tested.
Easy to implement.
Demonstrated low failure rate (0).

As I said, for the foreseeable future, nuclear pulse technology is not feasible. It is not practical. It is not safe. It is not affordable. It is by no means certain that it would work and if it did work, there is very little evidence to indicate how reliable it would be.

It's the sort of concept that physicists love and engineers loathe - because it's a nice idea in theory, but the practicalities make it unthinkable.

In 100 years time, maybe we could build a nice nuclear pulse powered ship on the Moon which could be used to travel really huge distances. Because huge distances are all it would be worth using it for - it's too stupidly dangerous and expensive for anything else and there are much more sensible alternatives that could be used.
Now I'm going to pare out everything that you didn't back up with an example, or a source, or even an ounce of logic as to why something may be true.

Berster7 wrote:

Give me a fucking reason why it is such high risk, or is barely possible (which is already a laughable way to state it because something that is barely possible can work just as well as something that has been possible for hundreds of years), or why it has a "suspected high failure rate through damage to the pusher plate"). Your analysis of the thermal nuclear system is as if not more flawed, but I'm not going to sit here going line by line about how stupidly devoid of thought it is. All rhetoric nonsense.

Berster7 wrote:

If you seriously think nuclear pulse rockets are something that could be used anytime over the next decade for anything other than a global catastrophy where safety and cost cease to be an issue, then you are mad.
Fuck off with this decade bullshit. I never said anything about the next decade.
Bertster7
Confused Pothead
+1,101|6583|SE London

Flaming_Maniac wrote:

Berster7 wrote:

You don't have an engineering background do you?

It shows.

It's a very simple principle, actually doing it would be incredibly difficult. Whereas NERVA based designs are very complicated in principle, but the application of these principles is easy. The number of things that could go horribly wrong with pulse based designs (not to mention all the other things) makes them impractical.

You really need to start getting your information from somewhere that isn't Wikipedia. It is not a strong scientific source and doesn't show both sides of this picture at all.
Hey look, you said nothing here. You attack my credibility, you attack the credibility of sources, you say "the number of things that could go horribly wrong...makes them impractical", and not once did you actually give a reason as to why I am wrong, why my sources are wrong, what exactly could go wrong. Now I haven't finished reading your post but this entire block of text is completely pointless.
No - it's pointing out you should use proper sources (not necessarily to link people to - but to educate yourself properly on the topic), not Wikipedia.

Flamng_Manc wrote:

Berster7 wrote:

This statement really shows you haven't understood the main risk here. It is not from any sort of nuclear reaction - it's from the spacecraft exploding in a catastrophic manner and showering a huge area with radioactive material. Those are the risks of using NERVA based designs and you would have a greater risk transporting the much larger quantities of nuclear material into orbit to fuel a nuclear pulse based craft. It's a much more significant risk because of the volumes of nuclear material involved that could irradiate huge areas. It has already been demonstrated in loads of tests that there is no way to reliably secure a payload against catatrophic failure - if the rocket blows up, the payload is exposed.
hurr durr that is exactly what I was talking about. I don't know how you missed this, I even used the word payload.
You also used the very specific term nuclear reaction. Which is utterly irrelevant.

Flamng_Manc wrote:

Flaming_Maniac wrote:

It is not particularly easy to instigate a nuclear reaction without making an effort, and it is certainly very difficult to accidentally start a nuclear reaction when the payload has been secured against even a catastrophic failure.
So a) an accidental nuclear reaction even in the event of catastrophic failure is less than unlikely and b) we can build a black box that can secure 1 gram of nuclear material after you assume there is no accidental nuclear reaction. Unless of course you can provide proof that "It has already been demonstrated in loads of tests that there is no way to reliably secure a payload against catatrophic failure"? I mean if it has been demonstrated in loads of tests, why didn't you provide one? If you are willing to bring relatively small loads at a time to build up the stockpile you need over many, many chemical launches the  additional risk is marginal. 1 gram is not a realistic figure, it is a figure to demonstrate my point. The cost of any such nuclear pulse rocket program would be so great that any number of launches to bring parts to be assembled in space, including the fuel, would be completely justified.

Flming_Manc wrote:

It is also impractical to launch such a craft by chemical rocket (since the craft would need to weigh so much), so it would need to be built in orbit or be able to get into orbit under nuclear pulse propulsion - madness. Building something like this in orbit is unrealistic at present.
Of course it would be assembled in space. This argument started from me stating that this would obviously be built in space.

Why is it unrealistic? Technologically it's not unrealistic. Given the drive we are perfectly capable of assembling large objects in space. Politically yes, it is unrealistic, but politically any of the missions that this type of technology would be used for is unrealistic. In the current political climate primarily because of the current economic climate going to Mars in the next ten years is completely unrealistic. Going to the moon in the next ten years is unrealistic. Reworking the goddamn shuttle system in the next ten years is unrealistic. But, when we are looking to seriously step up our space exploration, we would be seriously looking into assembling much larger structures in space, be it vessels, planetary bases, stations, whatever.
You don't seem very up to date with current NASA objectives. Within the next decade they plan to land on an asteroid and plan a manned mission to Mars by 2030.

Why is it unrealistic? Apart from not being possible with current technology? What makes you think that we are capable of doing so? Because it would be stupidly expensive. Projects which would have costs greater than the GDP of the most prosperous nation on Earth are unfeasible any time in the foreseeable future.

A sealed container withstand a rocket exploding You are optimistic. They've done tests on this and they didn't go well. Source - Fortescue P and Stark J, Spacecraft Systems Engineering.

They also touch on these principles in Wertz JR and Larson WJ, Space Mission Analysis and Design.

All the design work done worked on the principle that total containment was impossible and focused on limiting the spread of radioactive debris falling to Earth.

Berster7 wrote:

So:

Immense cost (really, truly, horrifically immense cost - we're talking tens of trillions here).
High risk.
Untested.
Barely possible with existing technology.
Suspected high failure rate (through damage to the pusher plates).

Vs.

Low cost (after a few launches the technology would have paid for itself).
Low risk (low volume of nuclear material carried into orbit the only risk).
Successfully tested.
Easy to implement.
Demonstrated low failure rate (0).

As I said, for the foreseeable future, nuclear pulse technology is not feasible. It is not practical. It is not safe. It is not affordable. It is by no means certain that it would work and if it did work, there is very little evidence to indicate how reliable it would be.

It's the sort of concept that physicists love and engineers loathe - because it's a nice idea in theory, but the practicalities make it unthinkable.

In 100 years time, maybe we could build a nice nuclear pulse powered ship on the Moon which could be used to travel really huge distances. Because huge distances are all it would be worth using it for - it's too stupidly dangerous and expensive for anything else and there are much more sensible alternatives that could be used.

Flmng_Mac wrote:

Now I'm going to pare out everything that you didn't back up with an example, or a source, or even an ounce of logic as to why something may be true.

Give me a fucking reason why it is such high risk, or is barely possible (which is already a laughable way to state it because something that is barely possible can work just as well as something that has been possible for hundreds of years), or why it has a "suspected high failure rate through damage to the pusher plate"). Your analysis of the thermal nuclear system is as if not more flawed, but I'm not going to sit here going line by line about how stupidly devoid of thought it is. All rhetoric nonsense.

Berster7 wrote:

If you seriously think nuclear pulse rockets are something that could be used anytime over the next decade for anything other than a global catastrophy where safety and cost cease to be an issue, then you are mad.
Fuck off with this decade bullshit. I never said anything about the next decade.
I've already given you reasons for all this stuff.

Risk - transport of nuclear material into space. Loads of it. Damage to pusher plates is considered by many to have too high a probability for the technology to be feasible with current engineering - the results of the Put Put tests were hardly conclusive, there were numerous failures.

You haven't addressed the cost issue - which is the main factor.

You claim my posts are devoid of thought when you just post ill informed opinions based on vague data in Wikipedia.


You're priceless.

Last edited by Bertster7 (2010-08-15 18:14:15)

11 Bravo
Banned
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Flaming_Maniac wrote:

Fuck off with this decade bullshit. I never said anything about the next decade.
3 day vacation sir.  you have been warned many times.
Flaming_Maniac
prince of insufficient light
+2,490|6708|67.222.138.85

Berster7 wrote:

No - it's pointing out you should use proper sources (not necessarily to link people to - but to educate yourself properly on the topic), not Wikipedia.
Tell me why I'm wrong, not that I'm wrong. All else is pointless if you don't actually say why I am wrong in the first place. Which you did not even attempt to do in that first block.

Berster7 wrote:

You also used the very specific term nuclear reaction. Which is utterly irrelevant.
I used the very specific term nuclear reaction because I can't believe that you would think containing a small amount of radioactive material would be an issue when the entire purpose of the mission would be the security of the package, even before the delivery of the package. A nuclear reaction would be the circumstance when all bets are off I should think.

Berster7 wrote:

You don't seem very up to date with current NASA objectives. Within the next decade they plan to land on an asteroid and plan a manned mission to Mars by 2030.
Jesus christ can you add?

Flaming_Maniac wrote:

In the current political climate primarily because of the current economic climate going to Mars in the next ten years is completely unrealistic.
2030 - (2010+10) = 10 years


Berster7 wrote:

Why is it unrealistic? Apart from not being possible with current technology? What makes you think that we are capable of doing so? Because it would be stupidly expensive. Projects which would have costs greater than the GDP of the most prosperous nation on Earth are unfeasible any time in the foreseeable future.
What technology is limiting us from making it happen?

Dude I went on about how politically unfeasible it is any time in the foreseeable future. Again you are trying to pin me into a time frame I have said nothing about.

Berster7 wrote:

A sealed container withstand a rocket exploding lol You are optimistic. They've done tests on this and they didn't go well. Source - Fortescue P and Stark J, Spacecraft Systems Engineering.

They also touch on these principles in Wertz JR and Larson WJ, Space Mission Analysis and Design.

All the design work done worked on the principle that total containment was impossible and focused on limiting the spread of radioactive debris falling to Earth.
WOW now you're giving me sources without content? Is it impossible to get a claim with a source produced in juxtaposition?

Berster7 wrote:

Damage to pusher plates is considered by many to have too high a probability for the technology to be feasible with current engineering - the results of the Put Put tests were hardly conclusive, there were numerous failures.
fucking source? Not even making the argument yourself, but pinning the content on "many" and no source?

Berster7 wrote:

You haven't addressed the cost issue - which is the main factor.
How is this the main factor? Any en devour is going to be stupidly expensive. If using nuclear pulse shaves decades off of the trip, even a cost difference on the order of magnitudes could be debated. I never said it was cheap, but technological feasibility is a hell of a lot more important than cost in getting these projects off the ground. Yes cost kills a lot of projects, but there is no point in even debating the cost of a project that is not technically viable.

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