Author Topic: Why are there so many threads on fusion, fission, anti-matter so on  (Read 15836 times)

Offline nec207

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 Why are there so many threads on fusion, fission, anti-matter rockets and other fuel source?

I can't help but it is obvious hot topic here.If I understand laws of chemistry apposed on rockets it would be impossible to use it to get in space.

If I understanding using other fuel source with higher energy density or other means of higher energy density would be apposed by the laws of chemistry.

With using a other fuel source with higher energy density preventing a explosion would be impossible.When you scale up the energy energy density it becomes unstable.


This is why NASA can't just find other fuel source that is more energy efficient.From what I understand it requires massive amount of energy to get in space.The problem is it takes energy to get in space so much energy the rocket wants to explode!!This is a engineering challenge for what they are using now.Switching to other fuel source with higher energy density would be even more energy and would explode.

In end it not the rockets are not energy efficient it is the laws of chemistry apposed on rockets. An analogy or metaphor would be like saying human body needs 2 000 calorie a day but to go up the stars to the 10th floor you need 5,000 calorie!!To do so you have to stop and eat on your way up.You can't eat 5,000 calorie at starting point you will get very sick.

So if you scale up the energy density it becomes unstable. Well yes the rocket is more energy efficient but it will explode.

Offline Aussie_Space_Nut

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Very briefly  :)

Getting to space requires that the payload reach orbital or escape velocity. Maximum energy over a short period of time. This challenge has been met today by the various chemical rocket motors out there.

Travel in space using chemical rockets is OK but is slow given that they can not fire indefinitely and end up quickly running out of fuel. So it's burn and coast.

Travel in space, manned craft. Ideally it would be great if you could create an environment where a constant 1G is experienced by the crew. One approach is to constantly fire your rocket all the way to your destination. Accelerate at 1G to the halfway point then turn around and decelerate at 1G to your destination. To do this you need a lot of energy over a long time. A lot of energy!

As it stands now electric rocket motors are greatly limited by their energy supplies. The equipment required to generate the energy is so heavy that the whole exercise becomes pointless.

This is one of the very many reasons why there is so much discussion about energy.

In this case the holy grail is a safe, light and powerful energy supply capable of powering a manned craft at a constant 1G acceleration over the entire length of the journey.

Free access to space,
Revelation NLT 21:15-16 The angel who talked to me held in his hand a gold measuring stick to measure the city, its gates, and its wall. 16 When he measured it, he found it was a square, as wide as it was long. In fact, its length and width and height were each 1,400 miles.

Offline aceshigh

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your post is a bit of a mess, but if I understand correctly, you are saying that you donīt think nuclear options can be used, because since chemical options are already on their theoretical limit of energy storage before becoming unstable... then it would be impossible to have even higher energy density fuels that would not be unstable... therefore, you are saying that fuel for fission and fusion would be unstable?

if I understood all that correctly... well, I suppose (if someone wants to correct my interpretation of it, feel free) the difference is exactly that its CHEMICAL fuels, where energy is stored at the bonds BETWEEN ATOMS AND MOLECULES (electrostatic force) which are at their limit before becoming unstable.

when we are talking about fission and fusion however, the energy is stored in the bonds holding the NUCLEUS together (strong nuclear force)

As for fission fuel, well, it IS unstable. Thatīs why there is radioactive decay (heavy atoms are unstable, but they are much easier to fission). But not unstable enough to explode. Proof? We DO have working fission powerplants, with controlled fission.

http://en.wikipedia.org/wiki/Fission_power
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Both fission and fusion appear promising for space propulsion applications, generating higher mission velocities with less reaction mass. This is due to the much higher energy density of nuclear reactions: some 7 orders of magnitude (10,000,000 times) more energetic than the chemical reactions which power the current generation of rockets.

and fusion is not unstable, quite the contrary, itīs so difficult to achieve. There is huge energy stored in the bonds of strong nuclear force that hold the nucleus together. But to release it, you first need to fuse two nucleus of atoms into one, and that itself requires TREMENDOUS energy to overcome the electromagnetic energy that tries to keep a positive nucleus apart from another positive nucleus.

Offline nec207

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Very briefly  :)

Getting to space requires that the payload reach orbital or escape velocity. Maximum energy over a short period of time. This challenge has been met today by the various chemical rocket motors out there.
 

The problem with chemical rockets is they have very low specific impulse around 400.That means they only operate for only a few minutes before all the fuel is gone.The highest specific impulse ever achieved for a chemical rocket was around 500 using Hydrogen ,Lithium and Fluorine.But was ridiculously hazardous and very challenging.And never will be used again because it is very hazardous and very dangerous.Trying to get chemical rockets to operate on higher specific impulse around 500 or 600 or higher is just too hazardous and very dangerous.It becomes too hot and wants to explode and thus you need new strong rocket material and think rocket.

Well Ion engines and Plasma engines have very high specific impulse but very low thrust so would never take off from earth and bust be use in space only , not taking off from earth.Other option for even higher specific impulse are Fission rockets or fusion rockets that have a reactor to heat a gas and blast it out the back.But the rocket would probably explode because the thrust is too high.

These rockets with very high specific impulse can operate for years in space with out refueling!!! But chemical rockets with such low specific impulse would only operate for few minutes before all the fuel is gone.

Offline Nilof

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If you haven't already, I suggest checking out this website thouroughly: http://www.projectrho.com/public_html/rocket/index.php

It has a lot of information on the basics of space travel and the not-so-basics of space travel with advanced propulsion systems.

However, if you REALLY want a good intuitive understanding of space travel and orbital mechanics, I suggest buying and installing Kerbal Space Program. It'll let you build rockets and control them yourself to get som hands on experience, while providing lots of entertainment and explosions along the way. It makes some simplyfying approximations and strongly overestimates hardware reliabillity, but the physics are accurate and you'll learn a lot from it. You can buy it on their website or on steam.

It's mostly focused on chemical propulsion with the only exceptions being an Ion engine and a NERVA-like Nuclear thermal engine, but there are mods to add in more speculative types of engines if you'd like. However, I strongly suggest playing with the stock game parts to begin with, as too powerful parts might ruin the gameplay to some extent as they can make the game too easy.
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline nec207

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If you haven't already, I suggest checking out this website thouroughly: http://www.projectrho.com/public_html/rocket/index.php

It has a lot of information on the basics of space travel and the not-so-basics of space travel with advanced propulsion systems.

However, if you REALLY want a good intuitive understanding of space travel and orbital mechanics, I suggest buying and installing Kerbal Space Program. It'll let you build rockets and control them yourself to get som hands on experience, while providing lots of entertainment and explosions along the way. It makes some simplyfying approximations and strongly overestimates hardware reliabillity, but the physics are accurate and you'll learn a lot from it. You can buy it on their website or on steam.

It's mostly focused on chemical propulsion with the only exceptions being an Ion engine and a NERVA-like Nuclear thermal engine, but there are mods to add in more speculative types of engines if you'd like. However, I strongly suggest playing with the stock game parts to begin with, as too powerful parts might ruin the gameplay to some extent as they can make the game too easy.

I was not really asking how all these propulsion systems work.What I seem to be confused about is the laws of chemistry apposed on rockets. I was asking this in other thread. And applying this to all propulsion systems.

When I said.

Quote
One of the main problems with getting up into space other than cost problem is fuel!! Getting in space 90% to 95% of the rocket is just fuel to get that small 5% payload up there, current rockets are multi-stage clamber to reach orbit. The fuel packs just enough of a punch to make the trip at all!!!!!! It uses fuel like drunken sailor!!!!!

I was saying they need to research other fuel sources that is more fuel efficient.Some people where saying that may not be possible because of limitations imposed by chemistry on rockets.

And I'm applying it to all propulsion systems. One of the members above said
Quote
CHEMICAL fuels, where energy is stored at the bonds BETWEEN ATOMS AND MOLECULES which are at their limit before becoming unstable.

So in way laws of chemistry apposed on rockets.So I read more threads and I than came to conclusion base on what I read.And said.

Quote
The problem with chemical rockets is they have very low specific impulse around 400.That means they only operate for only a few minutes before all the fuel is gone.The highest specific impulse ever achieved for a chemical rocket was around 500 using Hydrogen ,Lithium and Fluorine.But was ridiculously hazardous and very challenging.And never will be used again because it is very hazardous and very dangerous.Trying to get chemical rockets to operate on higher specific impulse around 500 or 600 or higher is just too hazardous and very dangerous.It becomes too hot and wants to explode and thus you need new strong rocket material and think rocket.

Well Ion engines and Plasma engines have very high specific impulse but very low thrust so would never take off from earth and bust be use in space only , not taking off from earth.Other option for even higher specific impulse are Fission rockets or fusion rockets that have a reactor to heat a gas and blast it out the back.But the rocket would probably explode because the thrust is too high.


So I was getting at rocket with high thrust and high specific impulse solving chemical rockets problem of high thrust and very low specific impulse problem.


sorry if this thread is all over the place but my past threads are confusing me on this topic of the laws of chemistry apposed on rockets.

May be the thread should been worded in way of solving chemical rockets problem of high thrust and very low specific impulse.

Does
Quote
CHEMICAL fuels, where energy is stored at the bonds BETWEEN ATOMS AND MOLECULES which are at their limit before becoming unstable.
apply to all forms.

Finding way of high thrust and high specific impulse.
« Last Edit: 05/27/2014 04:53 am by nec207 »

Offline 93143

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The idea that improving launch rockets significantly beyond the state of the art would involve unacceptable hazards and difficulties only applies to chemical rocketry, because the reason for it is that the chemicals you'd need to use are dangerous.

For example, using fluorine instead of oxygen in a hydrogen-fueled rocket could improve performance substantially, but fluorine is horribly poisonous and hard to handle, and the exhaust would be hydrofluoric acid instead of steam.  Ozone would be good too; unfortunately it is also very poisonous, and it tends to decompose spontaneously (and exothermically) even at moderate concentrations in LOX.  The problem is specifically the chemicals, not the heat and pressure they generate in the engine.

This has nothing whatsoever to do with fission, fusion, airbreathing, or any other method that isn't a chemical rocket.  Such methods have different problems, which are potentially surmountable.
« Last Edit: 05/27/2014 05:55 am by 93143 »

Offline ChrisWilson68

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I was not really asking how all these propulsion systems work.What I seem to be confused about is the laws of chemistry apposed on rockets.

I think the reason people are pointing you to information on the fundamentals of rocketry and physics is that you don't seem to have a grasp of even the most basic principles.  You also have grammatical problems in your posts, and the result of all of that is that it's hard to even tell what you're talking about.

For example, in the two sentences I quoted above, it's hard to tell what you mean.  The first sentence seems to imply you are saying you understand the basic principles of chemical rocket propulsion, among others.  The second sentence seems to be you saying you are confused by the laws of chemical rocket propulsion.
« Last Edit: 05/27/2014 06:02 am by ChrisWilson68 »

Offline ChrisWilson68

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Also, I would recommend you stop using the word "apposed".  You use it a lot and everywhere you use it it's very difficult to figure out what you might be trying to say.

Offline savuporo

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.. grasp of even the most basic principals.  You also have grammatical problems in your posts

.. principals of chemical rocket propulsion, among others. 
I cringed at the first one but .. cannot let this go. Principles !!
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Offline john smith 19

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Well Ion engines and Plasma engines have very high specific impulse but very low thrust so would never take off from earth and bust be use in space only , not taking off from earth.Other option for even higher specific impulse are Fission rockets or fusion rockets that have a reactor to heat a gas and blast it out the back.But the rocket would probably explode because the thrust is too high.
Your assumptions are wrong. Properly designed rockets do not explode because they are designed for that level of thrust.  Both fission and antimatter are potentially capable of generating enough thrust for Earth takeoff.

I think you've pretty much answered your own question. Better power sources --> higher thrust, longer duration ion and plasma engines --> more payload moved to greater destinations faster.

BTW. Spell checking is not proof reading.  :( "Apposed" is a word, but 99% of the time I doubt it's the one you want to use.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper Žcheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline nec207

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I was not really asking how all these propulsion systems work.What I seem to be confused about is the laws of chemistry apposed on rockets.

I think the reason people are pointing you to information on the fundamentals of rocketry and physics is that you don't seem to have a grasp of even the most basic principles.  You also have grammatical problems in your posts, and the result of all of that is that it's hard to even tell what you're talking about.

For example, in the two sentences I quoted above, it's hard to tell what you mean.  The first sentence seems to imply you are saying you understand the basic principles of chemical rocket propulsion, among others.  The second sentence seems to be you saying you are confused by the laws of chemical rocket propulsion.

It is little hard for me to get my thoughts together to ask an intelligent question when I have fragmented knowledge and confused what I'm reading.

I said
Quote
One of the main problems with getting up into space other than cost problem is fuel!! Getting in space 90% to 95% of the rocket is just fuel to get that small 5% payload up there, current rockets are multi-stage clamber to reach orbit. The fuel packs just enough of a punch to make the trip at all!!!!!! It uses fuel like drunken sailor!!!!!

I was saying they need to research other fuel sources that is more fuel efficient.Some people where saying that may not be possible because of limitations imposed by chemistry on rockets.

I did some reading today and don't know if I'm interpeding it right but saying generally been a trade-off between high thrust and high specific impulse. You can have one at the expense of the other, but not both. An exception would be nuclear pulse propulsion where exploding nuclear bombs behind the ship to propel it.

So in way saying no you cannot have high thrust and high specific impulse it is normally one or the other not both.

 

Offline IRobot

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I did some reading today and don't know if I'm interpeding it right but saying generally been a trade-off between high thrust and high specific impulse. You can have one at the expense of the other, but not both. An exception would be nuclear pulse propulsion where exploding nuclear bombs behind the ship to propel it.

So in way saying no you cannot have high thrust and high specific impulse it is normally one or the other not both.
That is only true for some engines, like Ion engines. It is not true for chemical engines. Actually, AFAIK, it is actually the opposite for chemical engines, although it does not have so much impact as with Ion engines.

Offline nec207

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The idea that improving launch rockets significantly beyond the state of the art would involve unacceptable hazards and difficulties only applies to chemical rocketry, because the reason for it is that the chemicals you'd need to use are dangerous.

For example, using fluorine instead of oxygen in a hydrogen-fueled rocket could improve performance substantially, but fluorine is horribly poisonous and hard to handle, and the exhaust would be hydrofluoric acid instead of steam.  Ozone would be good too; unfortunately it is also very poisonous, and it tends to decompose spontaneously (and exothermically) even at moderate concentrations in LOX.  The problem is specifically the chemicals, not the heat and pressure they generate in the engine.

This has nothing whatsoever to do with fission, fusion, airbreathing, or any other method that isn't a chemical rocket.  Such methods have different problems, which are potentially surmountable.

Okay so If I understand this is chemical rocketry only and not because higher energy density burn really hot but the chemicals they use.

So it was false when I said  Switching to other fuel source with higher energy density would be even more energy and would explode It has nothing to do with higher energy density are dangerous and hazardous it the chemical that determine if it is dangerous and hazardous.

It was also false when I said than.

Quote
I was saying they need to research other fuel sources that is more fuel efficient.Some people where saying that may not be possible because of limitations imposed by chemistry on rockets.

So it has nothing to do with chemistry imposed rockets of higher energy density having higher specific impulse being dangerous and hazardous!! It is what chemical they use has a fuel?

Offline nec207

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I did some reading today and don't know if I'm interpeding it right but saying generally been a trade-off between high thrust and high specific impulse. You can have one at the expense of the other, but not both. An exception would be nuclear pulse propulsion where exploding nuclear bombs behind the ship to propel it.

So in way saying no you cannot have high thrust and high specific impulse it is normally one or the other not both.
That is only true for some engines, like Ion engines. It is not true for chemical engines. Actually, AFAIK, it is actually the opposite for chemical engines, although it does not have so much impact as with Ion engines.

Could this be true for fission but not fusion or anti-matter?

So fusion or anti-matter can have high thrust and high specific impulse but not fission with the exception would be nuclear pulse propulsion where exploding nuclear bombs behind the ship to propel it

Offline JasonAW3

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Ok,

Simple answers.

Chemical rockets have an upper limit as to how fast they can go with a given amount of fuel.

Ion Rockets can go really fastwith very little fuel but don't put out a lot of thrust initially and take a LONG time to get up to speed.  (Not powerful enough to lift of the planet.)

The idea behind Fission and Fusion rockets is to get the fuel REALLY hot so it expands faster than the fuel from a chemical rocket would.  The advantage here is that you can get a lot of thrust for a much smaller amount of fel than it would take for a chemical rocket, (Good for boosting to orbit), and once in space, it could give a big initial push and be throttled back for a continious thrust, similar to the Ion engine.

Problem is, Fission engines require a nuclear reactor which will involve radioactive materials. An accident could contaminate a large area. And we haven't quite figured out Fusion Rockets or reactors yet, but there's been some very promising developments on this over the last year or so.

Anti-matter could take a mass of anti-matter about the size of a quarter and slowly combine it with an equal amount of matter and produce enough thrust to go ANYWHERE in the solar system in a few weeks, under a continious thrust.  Problem here, we still don't know how to make large quantities of anti-matter and haven't quite licked the problem of containing the antimatter for storage, let alone trickle it out as a fuel source.

Hope this tells you what you wanted to know.
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Offline nec207

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Ok,

Simple answers.

Chemical rockets have an upper limit as to how fast they can go with a given amount of fuel.

Ion Rockets can go really fastwith very little fuel but don't put out a lot of thrust initially and take a LONG time to get up to speed.  (Not powerful enough to lift of the planet.)

The idea behind Fission and Fusion rockets is to get the fuel REALLY hot so it expands faster than the fuel from a chemical rocket would.  The advantage here is that you can get a lot of thrust for a much smaller amount of fel than it would take for a chemical rocket, (Good for boosting to orbit), and once in space, it could give a big initial push and be throttled back for a continious thrust, similar to the Ion engine.

Problem is, Fission engines require a nuclear reactor which will involve radioactive materials. An accident could contaminate a large area. And we haven't quite figured out Fusion Rockets or reactors yet, but there's been some very promising developments on this over the last year or so.

Anti-matter could take a mass of anti-matter about the size of a quarter and slowly combine it with an equal amount of matter and produce enough thrust to go ANYWHERE in the solar system in a few weeks, under a continious thrust.  Problem here, we still don't know how to make large quantities of anti-matter and haven't quite licked the problem of containing the antimatter for storage, let alone trickle it out as a fuel source.

Hope this tells you what you wanted to know.

JasonAW3 your reply answers other propulsion systems. I'm still interested why Chemical rockets have an upper limit? Is it higher energy density or it the chemical that they use determine if it is dangerous and hazardous?

If it is the chemicals? If it is the chemicals ??? ??? there still may be a fuel source they have not found or have to make that it is not dangerous and hazardous.

If it is higher energy density that will not matter.


So no idea where this chemistry imposed on rockets came from if it has nothing to do with energy density that are dangerous and hazardous but the chemical.

Offline hop

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It's not complicated, there's only so much energy you can get out a chemical reaction.

LOX/LH2 is almost as good as it gets, and the things that could theoretically give higher performance all have major drawbacks. There is really no chance of something dramatically better coming along.

Offline the_other_Doug

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To be just a bit blunt about it, the reason there is so much discussion about the non-existent (as of now) technologies mentioned by the OP is that people (myself included) desperately want the science fiction futures we've been reading about our whole lives to become realities right now.

For those in their 20s and 30s, y'all want to change the world and are convinced that it just takes one little thing -- be it a tech breakthrough or just a tiny little alteration to the laws of physics (I mean, c'mon, just a tiny change, who's gonna notice?) -- to make their own blindered visions of the future a glorious reality, preferably next week sometime.

For those of us approaching or in our 60s or beyond, we're ever more aware of our mortality and want to see some things happen before we are forced to shuffle off.

So, there is a lot of emotional investment in finding a way to make miracle technologies happen immediately -- last week if not sooner.  And since we have achieved a lot of miraculous technologies over the past 150 years, all we gotta do is push a little to get that warp drive, or that personal FTL spacecraft, or great space liners supporting the Great Exodus Of Mankind To The Stars, where we can find the Vulcans and finally have discussions with logical beings...

This seems to lead a lot of people (many of whom are not really properly educated in the fields they discuss) to lock onto a particular something that seems to make sense to them and which will, in their minds, provide the miracles they seek.  (Do a web search on cold fusion sometime, to see what I mean, just to give one in a zillion examples.)

And it's not just a recent thing -- it is the same phenomenon as, over the centuries, there being alchemists who were convinced they just needed the right formulae to turn lead to gold, or theologians who thought that with just a tiny little change to human nature (again, just tiny, who'd notice?) they could bring their own vision of God's Kingdom to Earth.

The big difference is that now, in the early 21st century, we have internet blogs and flora where anyone, regardless of his/her background and ability, can pontificate endlessly on exactly what everyone else needs to do (or believe, or support, or give their money to, etc., etc.) to make their own blindered visions become the reality they so desperately crave.

Regardless of whether these realities are at all possible, or even desirable.

Just my two cents.

-Doug (with my shield, not yet upon it)
-Doug  (With my shield, not yet upon it)

Offline savuporo

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It's not complicated, there's only so much energy you can get out a chemical reaction.

LOX/LH2 is almost as good as it gets, and the things that could theoretically give higher performance all have major drawbacks. There is really no chance of something dramatically better coming along.

Oh, there are much better things ! Who doesnt love their smell of perchloryl fluoride in the morning ?

;)
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Offline john smith 19

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Oh, there are much better things ! Who doesnt love their smell of perchloryl fluoride in the morning ?

;)
Anyone who's survived a spill of the stuff?  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper Žcheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline nec207

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To be just a bit blunt about it, the reason there is so much discussion about the non-existent (as of now) technologies mentioned by the OP is that people (myself included) desperately want the science fiction futures we've been reading about our whole lives to become realities right now.

 

 Doug you the one bringing up science fiction.No one here is asking to go from one star system to the next .We have not even mastered are solar system that alone going from one star system to the next .We are still learning how to get in space!!

On other note science fiction like star wars or star trek make going in space very easy and that not the case how the laws of physics work.I feel like pushing my TV when science fiction writers show a starship take off and no smoke or explosion sound. Look at the space shuttle it takes so much energy to get in space you can hear explosion sound and big smoke miles away!!!

The problem with science fiction writers is they do not understand how much engery it takes to get in space and than energy going from one star system to the next. Even if there was some kind of deuterium or dilithium crystals like in star trek , one the ship would explode because of so much energy and second you would see so much smoke and explosion sound!!

Here is a simple experiment get a skateboard and turn on the garden hose it will pushes you back than get a skateboard and fire hose hooked up to big fire truck and you will be tossed to the ground to point of getting hurt. There only so much energy to point enery push back.

A rocket is bomb that operates on newton's third law for every action there is an equal opposite reaction.A rocket is controlled bomb to stop it from exploding it harnesses newton's third law.

You get too much energy you cannot control the bomb and it will explode.



Offline JohnFornaro

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Ya made me look:

appose: vt: 1 : archaic to put before : apply (one thing) to another 2 : to place in juxtaposition or proximity.

The use of the word "apposed" serves little pragmatic function when used by the original poster, with the idea that "pragmatic function" serves to inform the reader.  Perhaps there's a native language issue here?  Lord knows, I'm pretty damn good with English, but I attempt nothing more than simple restaurant style conversation in a few of the Romance languages.

Quote from: The-Other-Doug
To be just a bit blunt about it, the reason there is so much discussion about the non-existent (as of now) technologies mentioned by the OP is that people (myself included) desperately want the science fiction futures we've been reading about our whole lives to become realities right now.

I think Doug is spot on. 

My personal view has to do with humanity consciously and deliberately attempting a colonization effort on the two nearest destinatins, using chemical rocketry.  It is virtually certain that we have the means, the methods, and the money in order to attempt this effort.  The reasons for not doing so have mostly to do with the political systems of the world not being in support of that idea or effort, and the populations of the world are far too ensconced in daily survival to contemplate any larger human destiny than seeing another sunrise.  In my view, an off-planet society, economy, and frontier on Luna and Mars would be sufficient for the foreseeable future.  There would probably be a good development path on SEP and similar propulsion systems, once a regular cycling paradigm could be established.

I typically look askance at all the antimatter and other exotic proposals.  But that's just me.

I made an attempt to collect at least the top five reasons that most of the so-called advanced propulsion ideas are not viable, but my choice of topic title was insufficiently non-judgemental:

http://forum.nasaspaceflight.com/index.php?topic=34318.0

The mods decided that it was better for the forum that the issues of non-viability be addressed with each new instance of a new propulsion idea.

Finally, the original poster does not evince an understanding of many of the explanations offered by the posters above.
« Last Edit: 06/03/2014 01:36 pm by JohnFornaro »
Sometimes I just flat out don't get it.

Offline micawber

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my personal view is that in the far,far, far future flying around  in spaceships will be redundant. It seems to me the only way of crossing vast tracts of spacetime is not to try and fly through it as it takes too long and too much effort. Rather we know spacetime can be bent and shaped. One day if we could control the bending of spacetime then I envisage that travelling anywhere in the universe would be the same as stepping through a door.

How I imagine this would be like to use would be to step up to a door of a room/machine. On the other side, the destination you want to go too (anything from the most distant galaxy in the universe to the local shop down the road, would have spacetime bent to such an extent that your destination is now positioned on the other side of the door. you open the door (the door opens for you) you step across and are standing at you destination. the whole of the space time instantaneously unbends and returns to the its original position with you standing on it.

maybe not even a room just an wearable device that bends you destination to appear before you; either way vast travel would be done in one step.

no need to fly around in metal tubs, the only problem is we would all get exceedingly fat as we'd not have to actually walk anywhere any more  ;)
« Last Edit: 06/03/2014 02:07 pm by micawber »

Offline IslandPlaya

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You should read more books like this
http://www.wilmccarthy.com/lit.htm
rather than hanging around here mate!

Offline savuporo

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Oh, there are much better things ! Who doesnt love their smell of perchloryl fluoride in the morning ?

;)
Anyone who's survived a spill of the stuff?  :(

Not sure if  A. G. Streng is still around, low odds i think
Quote
The paper goes on to react FOOF with everything else you wouldn't react it with: ammonia ("vigorous", this at 100K), water ice (explosion, natch), chlorine ("violent explosion", so he added it more slowly the second time), red phosphorus (not good), bromine fluoride, chlorine trifluoride (say what?), perchloryl fluoride (!), tetrafluorohydrazine (how on Earth. . .), and on, and on. If the paper weren't laid out in complete grammatical sentences and published in JACS, you'd swear it was the work of a violent lunatic. I ran out of vulgar expletives after the second page. A. G. Streng, folks, absolutely takes the corrosive exploding cake, and I have to tip my asbestos-lined titanium hat to him.
Orion - the first and only manned not-too-deep-space craft

Offline Nilof

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Not sure if  A. G. Streng is still around, low odds i think


A quick google search on his name got me the wikipedia page for kypton difluoride. So clearly he's been busy oxidizing unoxidizable and exceptionally inert noble gases.

...and simultaneously creating an oxidizer that seems to be even more powerful than FOOF according to wikipedia:
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it is more powerful even that elemental fluorine due to the reduced bond F-F to Kr-F with redox potencial of 3.5, making it the most powerful known oxidising agent,  though KrF4 could be even stronger.
« Last Edit: 06/03/2014 04:25 pm by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline nec207

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Quote
  The reasons for not doing so have mostly to do with the political systems of the world not being in support of that idea or effort, and the populations of the world are far too ensconced in daily survival to contemplate any larger human destiny than seeing another sunrise.  In my view, an off-planet society, economy, and frontier on Luna and Mars would be sufficient for the foreseeable future.  There would probably be a good development path on SEP and similar propulsion systems, once a regular cycling paradigm could be established.


It is not political support it is cost!! Only three countries can put people in space.And I don't see that changing any time soon!! If may be lucky one or two more countries in next 20 years from now.

Europe does not have money and can hardly run welfare state. Poverty is still major problem even in rich countries and health care is not what doctors will like to have it.Money money money is big problem and government does not have cash for billion dollars mars exploration that alone trillion dollar for mars colony that would have to be support like the Antarctica to planet terraforming is in place that would take a very long time and cost trillions , trillions , trillions , trillion of dollars.



Quote
I typically look askance at all the antimatter and other exotic proposals.  But that's just me.


chemical propulsion is not going to get us to other star system ever. Even Ion or plasma does not even get close.


Well fission or fusion will get you close to the speed of light and anti-matter almost at the speed of light.

No exotic propulsion system will get you faster than speed of light that is impossible by the laws of physics.

With out warp drive even with anti-matter you will never travel less than 1% in the milky way even in generation ship. The milky way just too big.

Quote
I made an attempt to collect at least the top five reasons that most of the so-called advanced propulsion ideas are not viable, but my choice of topic title was insufficiently non-judgemental:

I have not seen threads but we have to talk reality not fantasy.You can't say forget  Ion , plasma , fission or fusion it will not get us use less than 1% in the milky way even in generation ship that talk warp drive.

We do not even know if warp drive or some thing like a warp drive is even possible or even clue how to build it.



 
 

Offline nec207

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my personal view is that in the far,far, far future flying around  in spaceships will be redundant. It seems to me the only way of crossing vast tracts of spacetime is not to try and fly through it as it takes too long and too much effort. Rather we know spacetime can be bent and shaped. One day if we could control the bending of spacetime then I envisage that travelling anywhere in the universe would be the same as stepping through a door.

How I imagine this would be like to use would be to step up to a door of a room/machine. On the other side, the destination you want to go too (anything from the most distant galaxy in the universe to the local shop down the road, would have spacetime bent to such an extent that your destination is now positioned on the other side of the door. you open the door (the door opens for you) you step across and are standing at you destination. the whole of the space time instantaneously unbends and returns to the its original position with you standing on it.

maybe not even a room just an wearable device that bends you destination to appear before you; either way vast travel would be done in one step.

no need to fly around in metal tubs, the only problem is we would all get exceedingly fat as we'd not have to actually walk anywhere any more  ;)




Even with warp drive it will take you centuries to to travel from one galaxy to next galaxy.
« Last Edit: 06/03/2014 06:20 pm by nec207 »

Offline nec207

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There is is other possibility not true space colonization but cool if earth is gone and you want a other space colonization .Take people DNA and send hundreds of small very small space probes to different planets  and one of them will get lucky and over time start life.This will be much cheaper.


Offline john smith 19

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It is not political support it is cost!! Only three countries can put people in space.And I don't see that changing any time soon!! If may be lucky one or two more countries in next 20 years from now.
If Skylon works that will change quite substantially.
Quote
Europe does not have money and can hardly run welfare state.
"Europe" or rather the EU is a group of 27 states. not including Norway.
Some are very prosperous and have excellent support for their citizens, others do not.

Equating where you live to everywhere else is a very dangerous idea.  :(

Quote
Poverty is still major problem even in rich countries and health care is not what doctors will like to have it.Money money money is big problem and government does not have cash for billion dollars mars exploration that alone trillion dollar for mars colony that would have to be support like the Antarctica to planet terraforming is in place that would take a very long time and cost trillions , trillions , trillions , trillion of dollars.
Which is why some people pin their hopes on "breakthrough" physics to lower the cost of space access enough to not need that level of support. Ironic given the problem is getting the first 150-300Km into space in the first place.  :(

BTW people do raise huge sums of cash for big projects. The going prices for a new wafer fab is about $3-4Bn. The Channel Tunnel cost about $15bn and the Airbus A380 about $10-12Bn.
Quote
chemical propulsion is not going to get us to other star system ever. Even Ion or plasma does not even get close.
Actually both solar sail and ion could with a big enough fuel tank. The idea of the Bussard ramjet was to extract power from interstellar hydrogen to continue to accelerate outside the solar system.
Quote
Well fission or fusion will get you close to the speed of light and anti-matter almost at the speed of light.
Fission won't. It's high thrust/high acceleration but low Isp is not enough to get the job done, unless you're looking at an Orion drive.
Quote
No exotic propulsion system will get you faster than speed of light that is impossible by the laws of physics.

With out warp drive even with anti-matter you will never travel less than 1% in the milky way even in generation ship. The milky way just too big.
IIRC There are studies on human expansion through the galaxy. I think what you mean is no individual could cover even a fraction of the milky way in 1 lifetime.

But I wonder have you factored in time dilation at close to the speed of light?
Quote
I have not seen threads but we have to talk reality not fantasy.You can't say forget  Ion , plasma , fission or fusion it will not get us use less than 1% in the milky way even in generation ship that talk warp drive.
I'm not really sure what  you're saying.
Quote
We do not even know if warp drive or some thing like a warp drive is even possible or even clue how to build it.
I still think you've pretty much answered you're own question.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper Žcheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline aceshigh

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We do not even know if warp drive or some thing like a warp drive is even possible or even clue how to build it.

Not really. We have clues on how to build warp drives. If the clues lead to anything, that's another question.

Dr Sony White , if i am not mistaken, believes he can create exotic matter from vacuum or something. Of course, even if it was possible, not even he thinks he can create three 1 ton needed by hits own calculations, for a warp drive. But hey, that's a clue.

Another clue is to use dr Woodward Mach Effect with Dr White s calcs for a warp drive ring. In theory, the mass fluctuation effect used to propellantless propulsion could be amplified until you can get the mass to be negative. Only 1ton needed for dr Sony White s warp.

Obviously, augmenting the effect until you get negative mass Is also faaaaaaar away, even if mach effect is proved to be real.

The point however ifs that we have clues. Even if they prove wrong or impossible, it's still clues.



Anyway, the solar system alone is big enough for at least two centuries of continuous exploration and colonization. No need for warp drives and such. For the moment, i will be content with fusion, fusion... anything that allow humans to reach Jupiter moons at least in a decent time
« Last Edit: 06/04/2014 02:14 pm by aceshigh »

Offline JasonAW3

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Ok,

Simple answers.

Chemical rockets have an upper limit as to how fast they can go with a given amount of fuel.

Ion Rockets can go really fastwith very little fuel but don't put out a lot of thrust initially and take a LONG time to get up to speed.  (Not powerful enough to lift of the planet.)

The idea behind Fission and Fusion rockets is to get the fuel REALLY hot so it expands faster than the fuel from a chemical rocket would.  The advantage here is that you can get a lot of thrust for a much smaller amount of fel than it would take for a chemical rocket, (Good for boosting to orbit), and once in space, it could give a big initial push and be throttled back for a continious thrust, similar to the Ion engine.

Problem is, Fission engines require a nuclear reactor which will involve radioactive materials. An accident could contaminate a large area. And we haven't quite figured out Fusion Rockets or reactors yet, but there's been some very promising developments on this over the last year or so.

Anti-matter could take a mass of anti-matter about the size of a quarter and slowly combine it with an equal amount of matter and produce enough thrust to go ANYWHERE in the solar system in a few weeks, under a continious thrust.  Problem here, we still don't know how to make large quantities of anti-matter and haven't quite licked the problem of containing the antimatter for storage, let alone trickle it out as a fuel source.

Hope this tells you what you wanted to know.

JasonAW3 your reply answers other propulsion systems. I'm still interested why Chemical rockets have an upper limit? Is it higher energy density or it the chemical that they use determine if it is dangerous and hazardous?

If it is the chemicals? If it is the chemicals ??? ??? there still may be a fuel source they have not found or have to make that it is not dangerous and hazardous.

If it is higher energy density that will not matter.


So no idea where this chemistry imposed on rockets came from if it has nothing to do with energy density that are dangerous and hazardous but the chemical.

Ok, Simply put, You can only get so much heat and energy out of a chemical reaction before you've expended all of the potentile energy that can be derived CHEMICALLY.  This means reduction to a stable state of molecular bonds.  While the molecular bonding can be broken down again, thos would require the input of more energy than would be derived.

Nuclear Fission releases energy by breaking down the ATOMS into both energy and smaller atoms, thus you are getting more potentile energy while reducing the fissable material to a lower energy state.

Fusion is combining two atoms of matter to create another atom of a less energetic state, Hydrogen and some of its' isotopes as well as Helium 3 are the best types of matter for this task.

Unless we figure out some form of Alchemicy, at present we cannot chemically fuse or split atoms, and are thus limited to as to how much energy can be drived from a chemical reation.

Hope this helps.
My God!  It's full of universes!

Offline Hog

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my personal view is that in the far,far, far future flying around  in spaceships will be redundant. It seems to me the only way of crossing vast tracts of spacetime is not to try and fly through it as it takes too long and too much effort. Rather we know spacetime can be bent and shaped. One day if we could control the bending of spacetime then I envisage that travelling anywhere in the universe would be the same as stepping through a door.

How I imagine this would be like to use would be to step up to a door of a room/machine. On the other side, the destination you want to go too (anything from the most distant galaxy in the universe to the local shop down the road, would have spacetime bent to such an extent that your destination is now positioned on the other side of the door. you open the door (the door opens for you) you step across and are standing at you destination. the whole of the space time instantaneously unbends and returns to the its original position with you standing on it.

maybe not even a room just an wearable device that bends you destination to appear before you; either way vast travel would be done in one step.

no need to fly around in metal tubs, the only problem is we would all get exceedingly fat as we'd not have to actually walk anywhere any more  ;)




Even with warp drive it will take you centuries to to travel from one galaxy to next galaxy.
This cant be stated with any certainty. No one knows any of the limits of faster than light travel, or if its even possible.
Paul

Offline micawber

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my personal view is that in the far,far, far future flying around  in spaceships will be redundant. It seems to me the only way of crossing vast tracts of spacetime is not to try and fly through it as it takes too long and too much effort. Rather we know spacetime can be bent and shaped. One day if we could control the bending of spacetime then I envisage that travelling anywhere in the universe would be the same as stepping through a door.

How I imagine this would be like to use would be to step up to a door of a room/machine. On the other side, the destination you want to go too (anything from the most distant galaxy in the universe to the local shop down the road, would have spacetime bent to such an extent that your destination is now positioned on the other side of the door. you open the door (the door opens for you) you step across and are standing at you destination. the whole of the space time instantaneously unbends and returns to the its original position with you standing on it.

maybe not even a room just an wearable device that bends you destination to appear before you; either way vast travel would be done in one step.

no need to fly around in metal tubs, the only problem is we would all get exceedingly fat as we'd not have to actually walk anywhere any more  ;)




Even with warp drive it will take you centuries to to travel from one galaxy to next galaxy.
This cant be stated with any certainty. No one knows any of the limits of faster than light travel, or if its even possible.

Just reiterate in my original post  I am thinking in the realms of science-fiction/far far far far future.  But the idea of taking centuries to travel from on galaxy to the next... It would if you were trying to travel through it. My suggestion is that rather than travel through spacetime, why not bend the whole of spacetime so where you want to get to and where you are in terms of distance is only one footstep.

We know that spacetime can be bent/curved many observations prove this. how to build a machine to control that and be able to be able to bend spacetime so that anypoint in the universe ends up spatially one footstep way is anybodies guess. But science fiction eventually becomes science fact. it just takes time. this might take a very long time though...  :) Still thought life has been kicking around for 4 billions years and has got as far Human beings and we are pretty complex things... so there is always hope. 

Offline Avron

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It is not political support it is cost!! Only three countries can put people in space.And I don't see that changing any time soon!! If may be lucky one or two more countries in next 20 years from now.
If Skylon works that will change quite substantially.

hold on... what's with 'IF"?
« Last Edit: 06/05/2014 02:55 am by Avron »

Offline ChrisWilson68

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We do not even know if warp drive or some thing like a warp drive is even possible or even clue how to build it.

Not really. We have clues on how to build warp drives. If the clues lead to anything, that's another question.

Dr Sony White , if i am not mistaken, believes he can create exotic matter from vacuum or something.

That's not a clue, that's just confused people believing another confused person because they want to believe what he says.

The reputable scientists that have examined Sony White's papers say he's incorrect in his conclusions.

With thousands upon thousands of university researchers out there, it's inevitable that one of the third-rate researchers will convince himself he's found something wonderful and not be smart enough to realize he's wrong, even when it's explained to him.  Then, all the people who want for it to be true who don't have enough understanding of how science works latch onto him.  It gives him lots of attention, so of course he has a lot of incentive to keep believing.  People are very good at continuing to believe something when it makes them feel good to believe it.
« Last Edit: 06/05/2014 09:27 am by Lar »

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