Author Topic: Alternative fuel source touted as 5-10 times cheaper than alternatives  (Read 11469 times)

Offline nec207

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I came across this article today it is saying it is 5-10 times more fuel efficient than wan't they are using now.

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!!
 

This new fuel they found Paraffin Based Fuel is 5-10 times more fuel efficient!!

Read here.
http://www.space.com/16378-hybrid-rocket-motor-test-spg.html

What are you thoughts on this? Would Monatomic Hydrogen + Fluorine be better option?

« Last Edit: 04/28/2014 08:35 pm by Lar »

Offline Jim

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I came across this article today it is saying it is 5-10 times more fuel efficient than wan't they are using now.

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!!
 

This new fuel they found Paraffin Based Fuel is 5-10 times more fuel efficient!!

Read here.
http://www.space.com/16378-hybrid-rocket-motor-test-spg.html

What are you thoughts on this? Would Monatomic Hydrogen + Fluorine be better option?



Cheaper not more efficient. 

Come on!.   Think!.  How can it be 5-10 times more fuel efficient?  The difference between RP-1/LOX and LH2/LOX is only 27% increase

Offline butters

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LOX/paraffin has a lower specific impulse than LOX/RP-1 even under ideal conditions. Additionally, the dry mass is higher because the fuel "tank" is also the combustion chamber and must have thick walls capable of withstanding high pressures. Finally, it is difficult to control or optimize the mixture ratio because the oxidizer burns the surface of the fuel casting (and affects its structural integrity) in an uncontrollable and relatively inconsistent manner, usually resulting in a substantial amount of unburned fuel in the exhaust.

Offline nec207

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LOX/paraffin has a lower specific impulse than LOX/RP-1 even under ideal conditions. Additionally, the dry mass is higher because the fuel "tank" is also the combustion chamber and must have thick walls capable of withstanding high pressures. Finally, it is difficult to control or optimize the mixture ratio because the oxidizer burns the surface of the fuel casting (and affects its structural integrity) in an uncontrollable and relatively inconsistent manner, usually resulting in a substantial amount of unburned fuel in the exhaust.

So why are they researching that fuel source if it is not more fuel efficient? Why not researching  to find alternative fuel source that is more fuel efficient.

Offline NovaSilisko

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Because fuel efficiency isn't the most important thing. If it was, you'd see nothing but LH2 and LOX vehicles. Cost is generally more important.
« Last Edit: 04/25/2014 07:35 pm by NovaSilisko »

Offline Jim

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals. 

Offline ClaytonBirchenough

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Because fuel efficiency isn't the most important thing. If it was, you'd see nothing but LH2 and LOX vehicles. Cost is generally more important.

And in the article it says, "...using the motor's hybrid technology have the potential to be five to 10 times cheaper than existing rockets."

Five to ten times cheaper would be beneficial even for only a 200 ISP motor.
Clayton Birchenough

Offline nec207

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals.

What do you mean?

Offline NovaSilisko

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And in the article it says, "...using the motor's hybrid technology have the potential to be five to 10 times cheaper than existing rockets."

Five to ten times cheaper would be beneficial even for only a 200 ISP motor.

Yep. Not sure where you're getting the "more fuel efficient" angle at all, nec207.

Offline Jim

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Because fuel efficiency isn't the most important thing. If it was, you'd see nothing but LH2 and LOX vehicles. Cost is generally more important.

And in the article it says, "...using the motor's hybrid technology have the potential to be five to 10 times cheaper than existing rockets."

Five to ten times cheaper would be beneficial even for only a 200 ISP motor.

But propellant cost are minor for launch vehicles.

Offline nec207

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And in the article it says, "...using the motor's hybrid technology have the potential to be five to 10 times cheaper than existing rockets."

Five to ten times cheaper would be beneficial even for only a 200 ISP motor.

Yep. Not sure where you're getting the "more fuel efficient" angle at all, nec207.

Okay I must of misinterpreted what I read.It is 5-10 times cheaper not 5-10 times more fuel efficient .

And yes both are major problem cheap access to space and more fuel efficient.

Offline ClaytonBirchenough

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But propellant cost are minor for launch vehicles.

But it says "... have the potential to be five to 10 times cheaper than existing rockets. Rockets, not fuel.
Clayton Birchenough

Offline NovaSilisko

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But propellant cost are minor for launch vehicles.

But it says "... have the potential to be five to 10 times cheaper than existing rockets. Rockets, not fuel.

I'd call that a mistake of the article author then. Jim's right, propellant costs are minor compared to everything else.

Offline Elmar Moelzer

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The cost of propellant for a Falcon9 launch is 200k USD according to Elon Musk. The current cost for a F9 launch is 60 million (or so). So the propellant cost is pretty much irrelevant. So I don't get what this article is aiming at.

Offline Lee Jay

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals. 

Well, there's solid metallic hydrogen.  But no one knows how to make it, store it, or do pretty much anything else with it other than study it.

Offline Nomadd

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The cost of propellant for a Falcon9 launch is 200k USD according to Elon Musk. The current cost for a F9 launch is 60 million (or so). So the propellant cost is pretty much irrelevant. So I don't get what this article is aiming at.
No, the price for launching an F9 is $60 million or so. The cost is less.
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Offline nec207

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals. 

Well, there's solid metallic hydrogen.  But no one knows how to make it, store it, or do pretty much anything else with it other than study it.


exactly they are researching other fuel sources for power stations ,airplanes and cars that are cheaper and more fuel efficient.Why not do the same with getting in space. Getting in space requires lots of fuel where 90% to 95% is just fuel to get that small 5% payload up there.Why not find alternate fuel source where only 40% or 15% of the rocket is fuel.You can take up lots of payload with a small rocket.

Offline cordwainer

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals.

Offline cordwainer

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals.
They've been researching more efficient fuels since the 1950's if they were going to discover unobtanium they would have by now. There is only so much energy you can get out of a fuel before it becomes an explosive. ADN and Ionic liquids offer some increased in energy but they burn really hot so you need better structural materials to make them work. Better structural materials makes your rocket engine more expensive. Similarly Ozone of Flourine as an oxidizer is more efficient as well but our highly corrosive and toxic. Even if you could make a rocket with those fuel mixtures at most you would only see about a 20% increase in efficiency so it's not really worth the cost for a launch rocket. On the other hand ionic fuels would be useful for bimodal propulsion systems for in-space maneuver engines like the Shuttle's OMS.

Offline Nilof

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For launching from Earth, the problem isn't so much the fuel efficiency alone as much as much as the balance between propellant efficiency and the requirement to produce more thrust than a hamster fart. Ion engines can be more than ten times more efficient than chemical, but their thrust is tiny and it has to be left on for months for the effect to add up significantly. So they're useful for in-space propulsion but clearly not for earth liftoff.

Because of conservation of momentum, the propellant efficiency is directly proportional to the exhaust velocity, which gives you the momentum change per kg of propellant (which americans multiply by g to get a number in seconds called Isp, specific impulse, for unit conversion related reasons). I suggest looking up the Tsiolkovsky rocket equation if you haven't already.

However, there is also a second quantity which is the ammount of thrust you get for a given power output. Power used ~ thrust*exhaust velocity. So to get more out of a given mass of fuel, you need it to pack more energy. However, there is a limit to how much energy you can get per mass out of a chemical reaction. It turns out that it's pretty much impossible to beat hydrogen + oxygen => water by that metric, with the only exceptions being hydrogen + fluorine compounds which can give you a few extra percent efficiency at the cost of complete impracticallity as demonstrated the sheer body count of professional chemists who have dabbled in fluorine chemistry.

The only way to get more energy per mass of propellant than current hydrogen + oxygen rockets is to abandon chemical propulsion altogether and go nuclear. However, even after accepting the fact that it's political feasibillity is questionable that option has it's problems and beating the thrust to weight ratio of chemical engines is difficult. You're either trading that fuel efficiency for lower thrust, or using a very agressive design that is likely to be spraying radioactive blue death on one end.

The other option is to not carry all the fuel with you, which usually means using the earth's atmosphere as propellant. I suggest looking up Skylon and it's SABRE engine for more on that approach. Another approach is to use som kind of laser to beam power to the vehicle, which incidentally does not exclude the previous approach of using the atmosphere as well. For that I'd suggest googling the Lightcraft which is a fairly innovative design which lacks many of the limitations of current rocket engines.
« Last Edit: 04/26/2014 03:30 am 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 ClaytonBirchenough

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Haha as long as were on the topic of exotic propellants, Wikipedia always makes me laugh when reading how terrible the Lithium-Fluorine fuel combination sounds and is. Here's a snippet:

Quote
The highest specific impulse chemistry ever test-fired in a rocket engine was lithium and fluorine, with hydrogen added to improve the exhaust thermodynamics (all propellants had to be kept in their own tanks, making this a tripropellant). The combination delivered 542 s specific impulse in a vacuum, equivalent to an exhaust velocity of 5320 m/s. The impracticality of this chemistry highlights why exotic propellants are not actually used: to make all three components liquids, the hydrogen must be kept below -252°C (just 21 K) and the lithium must be kept above 180°C (453 K). Lithium and fluorine are both extremely corrosive, lithium ignites on contact with air, fluorine ignites on contact with most fuels, including hydrogen. Fluorine and the hydrogen fluoride (HF) in the exhaust are very toxic, which makes working around the launch pad difficult, damages the environment, and makes getting a launch license that much more difficult. The rocket exhaust is also ionized, which would interfere with radio communication with the rocket. Finally, both lithium and fluorine are expensive and rare, enough to actually matter. This combination has therefore never flown.

It did achieve a specific impulse of 542 s though... ::) .
Clayton Birchenough

Offline nec207

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals.
They've been researching more efficient fuels since the 1950's if they were going to discover unobtanium they would have by now. There is only so much energy you can get out of a fuel before it becomes an explosive. ADN and Ionic liquids offer some increased in energy but they burn really hot so you need better structural materials to make them work. Better structural materials makes your rocket engine more expensive. Similarly Ozone of Flourine as an oxidizer is more efficient as well but our highly corrosive and toxic. Even if you could make a rocket with those fuel mixtures at most you would only see about a 20% increase in efficiency so it's not really worth the cost for a launch rocket. On the other hand ionic fuels would be useful for bimodal propulsion systems for in-space maneuver engines like the Shuttle's OMS.

May be I'm confusing researching alternate fuel source for cars ,airplanes and power stations with getting in space.Why that is possible but not alternate fuel source for getting in space.

My reading some of the replies above it seems has it is not going to get any more fuel efficient with out it being very dangerous to the point of explosion with out stronger materials for rocket to deal with it.

I don't know may be NASA is looking for other fuel source (have been looking for decades and have found none) or chemistry a fuel source they are using now is not going get any more fuel efficient than what they are using now.Don't know why. Other than poster above said it be too hot and may be unstable with out strong new materials for rocket for that fuel.Have to elaborate on that as I'm confused.

I thought the more densely packed molecules more energy output and more fual efficient.Where less densely packed molecules less energy output and less fual efficient?

But is this some kind of chemistry problem?
« Last Edit: 04/26/2014 03:02 am by nec207 »

Offline Lee Jay

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I think you don't really understand rockets.

With chemicals, you can calculate the theoretical maximums.  The highest practical combination is liquid hydrogen and liquid oxygen.  Even these are not always used because the volume of liquid hydrogen is large and because it's really terribly cold.  Nevertheless, the Shuttle used these.

To do better, you need electric propulsion (only useful when already in space due to low thrust) or some sort of nuclear propulsion.  All of these have been worked on and, short of a breakthrough in aneutronic fusion engines, first stages aren't going to change any time soon.

Offline Elmar Moelzer

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The cost of propellant for a Falcon9 launch is 200k USD according to Elon Musk. The current cost for a F9 launch is 60 million (or so). So the propellant cost is pretty much irrelevant. So I don't get what this article is aiming at.
No, the price for launching an F9 is $60 million or so. The cost is less.
Yes, but that little semantic indiscretion on my side does not change the point that the cost of fuel is pretty much irrelevant compared to the rest. Musk stated that they might be able to bring the price for a F9 launch down to 7 million with full reuse. In that case we are still only talking about 3% of he launch price that is due to the cost of fuel. It might become slightly more relevant then, but it is still not really a major contributor.
I think we still need a technical breakthrough of sorts before we can really colonize space on a grand scale. The fuel here is not going to change that anyway as it is only cheaper, but not more efficient.

Offline the_other_Doug

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I thought the more densely packed molecules more energy output and more fual efficient.Where less densely packed molecules less energy output and less fual efficient?

Think of it this way -- for chemical reactions, you can only pack so much potential energy into fuel(s).  I call this the energy density of the fuel(s).  Just having heavier atoms doesn't give you a better fuel, as heavier elements tend to be less chemically reactive.  For example, if you want to get a hotter campfire, do you add more wood (mostly carbon) or do you through some tire irons into the fire (mostly iron)?  Iron is a much denser atom, but carbon is much, much more reactive.  The amount of energy you can liberate via combustion in a carbon-based fuel is much greater than in an iron-based fuel.  Even though the iron is heavier.

Now, energy density goes up by orders of magnitude when you access the forces within the nucleus of the atom.  But this requires either fission or fusion, and that energy is released so quickly that you can't easily use it directly.  You have to interfere with a fission reaction and make it run really slowly to use it for power, and even then you usually just use the heat from the fission to make steam and use the steam to run generators.  In rocketry, you use the heat from a slow fission reaction to heat up an insert propellant and send it out the nozzle.  Again, you're a big step away from the actual energy inherent in the atomic forces, as you have to use the secondary effect of heat generated by slow moderated fission as you would use heat from burning fossil fuels.  (You could make a steam rocket engine using coal and water that would have the same thrust as a nuclear rocket, but it would be inferior in performance because the water and coal are a lot heavier than the fission pile and the propellant.

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Offline the_other_Doug

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I thought the more densely packed molecules more energy output and more fual efficient.Where less densely packed molecules less energy output and less fual efficient?

Think of it this way -- for chemical reactions, you can only pack so much potential energy into fuel(s).  I call this the energy density of the fuel(s).  Just having heavier atoms doesn't give you a better fuel, as heavier elements tend to be less chemically reactive.  For example, if you want to get a hotter campfire, do you add more wood (mostly carbon) or do you throw some tire irons into the fire (mostly iron)?  Iron is a much denser atom, but carbon is much, much more reactive.  The amount of energy you can liberate via combustion in a carbon-based fuel is much greater than in an iron-based fuel.  Even though the iron is heavier.

Now, energy density goes up by orders of magnitude when you access the forces within the nucleus of the atom.  But this requires either fission or fusion, and that energy is released so quickly that you can't easily use it directly.  You have to interfere with a fission reaction and make it run really slowly to use it for power, and even then you usually just use the heat from the fission to make steam and use the steam to run generators.  In rocketry, you use the heat from a slow fission reaction to heat up an insert propellant and send it out the nozzle.  Again, you're a big step away from the actual energy inherent in the atomic forces, as you have to use the secondary effect of heat generated by slow moderated fission as you would use heat from burning fossil fuels.  (You could make a steam rocket engine using coal and water that would have the same thrust as a nuclear rocket, but it would be inferior in performance because the water and coal are a lot heavier than the fission pile and the propellant.

-Doug  (with my shield, not yet upon it)
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Offline nec207

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I read alternative to Chemical rockets would be to use a reactor to heat a gas and blast it out the back. They say it is more fual efficient.

Can some one elaborate on that as I'm confused.


 

Offline Elmar Moelzer

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I read alternative to Chemical rockets would be to use a reactor to heat a gas and blast it out the back. They say it is more fual efficient.

Can some one elaborate on that as I'm confused.
This probably referred to nuclear thermal propulsion. Do a web search on NERVA and you will get an idea.

Offline Asteroza

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I wonder what kind of aluminum doping they are using in the paraffin wax fuel grain though? Nanoscale powdered aluminum supposedly isn't really better than regular powdered aluminum in terms of burns apparently, so maybe they went the alpha-alane crystal powder route?

Offline Cedalion

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I suggest you take the time to familiarise yourself with this helpful website: http://www.projectrho.com/public_html/rocket/enginelist.php

Offline R7

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The article is void of any hard facts backing up the statement "the motor's hybrid technology have the potential to be five to 10 times cheaper than existing rockets.".

Company's youtube videos show ugly combustion instabilities.
« Last Edit: 04/28/2014 08:37 pm by Lar »
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Offline kevin-rf

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Maybe they feel a hybrid motor could be made 5-10 times cheaper than current liquid (LH/LOX, RP-1/LOX, pick your poison) engines including the tanks, and stuff.

The point is not to make the rocket more efficient, but reaching orbit for less cost. The "promise" of hybrids is they can be done "cheaper". *Actual cost may vary.

Why buy a Mustang or Hybrid to drive to the store when a new pair of sneakers and legs 1.0 will do just fine.
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Offline dror

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But propellant cost are minor for launch vehicles.

But it says "... have the potential to be five to 10 times cheaper than existing rockets. Rockets, not fuel.

I'd call that a mistake of the article author then. Jim's right, propellant costs are minor compared to everything else.

No mistake. Maybe false but not by mistake.
The propelant is the cheap part, the engine and fuel tanks arent cheap. It is claimed that a rocket which is based on a hybrid Liquid O2 solid parafene motor will be simpler (and heavier) and will be 5-10 times cheaper.
Space is hard immensely complex and high risk !

Offline Vultur

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Why not researching  to find alternative fuel source that is more fuel efficient.

Because of physics, there isn't any more efficient chemicals. 

Well, there's solid metallic hydrogen.  But no one knows how to make it, store it, or do pretty much anything else with it other than study it.

Well, there is fluorine ;)

Unfortunately the exhaust is HF, which is extremely nasty, and plus it would probably be hard to keep the fluorine from eating the rocket...

Offline Adaptation

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Why not researching  to find alternative fuel source that is more fuel efficient.
Because of physics, there isn't any more efficient chemicals.

For MJ/kg (chemical energy density by mass) several metals like lithium, beryllium and maybe even aluminum or silicon can compete with hydro-lox. 

For instance hydrogen-oxygen is ~15.8 MJ/kg  lithium-oxygen is ~20 Mj/kg

Another benefit to metals is you can store a lot of energy in them by heating them up.  Lithium near its boiling point can store an extra 6.3 MJ/kg (thats just in the lithium, 2Li+O would average out to ~22.9 Mj/kg with near boiling molten lithium) 

A big problem with metal fuels though is that there oxides don't like to stay gasses.  And without hot expanding gases its hard to make a rocket go.  Sprinkling in a little metal with the fuel could help somewhat but liquid rockets have fast spinning pumps that probably wont like the metal flakes and you also don't want slag building up in your combustion chamber or nozzle.  Nano particles suspended in kerosene would probably work just fine but I not know if anyone has tried. 

Metals are a common ingredient in solid rockets but there is so much overhead in things like binders and heavy casings that they can't really come close to competing with liquids on efficiency.  Hybrids are somewhere in the middle. as far as I know they are barely scraping the bottom end of the commercial space with outfits like virgin galactic. 

Offline fatjohn1408

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The cost of propellant for a Falcon9 launch is 200k USD according to Elon Musk. The current cost for a F9 launch is 60 million (or so). So the propellant cost is pretty much irrelevant. So I don't get what this article is aiming at.
No, the price for launching an F9 is $60 million or so. The cost is less.
No, the price for launching an F9 is $60M or so. The cost is more.

Offline nec207

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I thought the more densely packed molecules more energy output and more fual efficient.Where less densely packed molecules less energy output and less fual efficient?

Think of it this way -- for chemical reactions, you can only pack so much potential energy into fuel(s).  I call this the energy density of the fuel(s).  Just having heavier atoms doesn't give you a better fuel, as heavier elements tend to be less chemically reactive.  For example, if you want to get a hotter campfire, do you add more wood (mostly carbon) or do you through some tire irons into the fire (mostly iron)?  Iron is a much denser atom, but carbon is much, much more reactive.  The amount of energy you can liberate via combustion in a carbon-based fuel is much greater than in an iron-based fuel.  Even though the iron is heavier.

That back track a bit on some basic chemistry before we can have a discussion about this.

The higher the energy density the more fuel efficient.The holy grail is to find higher energy density fuels that cheap at least for cars ,power stations and airplanes.There are many different matters in universal it just at this time fossil fuels is cheapest and has the higher energy density than any other fuel.

You can't just burned something because you want it to.It has to chemically burn.This is why cars don't run of sand, clay,water ,milk  or stones so on. It has to chemically burn and bonded with oxygen.If there was no oxygen than cars and airplanes would have to carry a oxygen tank like rockets do.

The reason we use fossil fuels is it is the cheapest and has higher energy density than any other fuels.There is some research going into methane ,ethanol ,biofuels like corn , vegetable oil and animal fats so on.But they have less energy density than fossil fuels so not as fual efficient.

But reading the replies here ( if I undestand ) rockets use hydrogen fuel as they have higher energy density than fossil fuels or biofuels.And say there are other fuel sources that have higher energy density , but the rockets get very hot and is unstabled and so the rockets needs strong materials because burning the fuel gets too hot and become unstabled.So I guess this is fundamental limitations imposed by the laws of chemistry on rockets.

So really rockets cannot get any more fuel efficient because switching to fuel source with higher energy density the rocket would become unstabled and way too hot with out new strong materials.

Offline DarkenedOne

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I thought the more densely packed molecules more energy output and more fual efficient.Where less densely packed molecules less energy output and less fual efficient?

Think of it this way -- for chemical reactions, you can only pack so much potential energy into fuel(s).  I call this the energy density of the fuel(s).  Just having heavier atoms doesn't give you a better fuel, as heavier elements tend to be less chemically reactive.  For example, if you want to get a hotter campfire, do you add more wood (mostly carbon) or do you through some tire irons into the fire (mostly iron)?  Iron is a much denser atom, but carbon is much, much more reactive.  The amount of energy you can liberate via combustion in a carbon-based fuel is much greater than in an iron-based fuel.  Even though the iron is heavier.

That back track a bit on some basic chemistry before we can have a discussion about this.

The higher the energy density the more fuel efficient.The holy grail is to find higher energy density fuels that cheap at least for cars ,power stations and airplanes.There are many different matters in universal it just at this time fossil fuels is cheapest and has the higher energy density than any other fuel.

You can't just burned something because you want it to.It has to chemically burn.This is why cars don't run of sand, clay,water ,milk  or stones so on. It has to chemically burn and bonded with oxygen.If there was no oxygen than cars and airplanes would have to carry a oxygen tank like rockets do.

The reason we use fossil fuels is it is the cheapest and has higher energy density than any other fuels.There is some research going into methane ,ethanol ,biofuels like corn , vegetable oil and animal fats so on.But they have less energy density than fossil fuels so not as fual efficient.

But reading the replies here ( if I undestand ) rockets use hydrogen fuel as they have higher energy density than fossil fuels or biofuels.And say there are other fuel sources that have higher energy density , but the rockets get very hot and is unstabled and so the rockets needs strong materials because burning the fuel gets too hot and become unstabled.So I guess this is fundamental limitations imposed by the laws of chemistry on rockets.

So really rockets cannot get any more fuel efficient because switching to fuel source with higher energy density the rocket would become unstabled and way too hot with out new strong materials.

No not exactly.  When it comes to good rocket fuels its not about energy density aka. energy per unit volume.  What makes a good rocket fuel is high specific energy, aka energy per unit mass.   Click on the link below for Wikipedia's article on energy density.  As you can see Hydrogen has very poor energy density, but it has the highest specific energy of all fuels.  That is why hydrogen rockets engines have the highest ISP. 

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

If you think about hydrogen and oxygen you will realize that they are essentially the lightest fuel and oxidizer pair on the periodic table.  As a fuel it does not get any lighter than hydrogen with just one proton.  As an oxidizer it does not get much better than oxygen.  The only oxidizer that could work better than oxygen is fluorine.  You essentially get a more energetic reaction for the cost of one additional proton,  Experimental rocket engines using fluorine were able to get into the low 500 ISP.  The problem with fluorine is that it is far more expensive, far more difficult to handle, far more environmentally damaging then oxygen, 


Offline Vultur

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The cost of propellant for a Falcon9 launch is 200k USD according to Elon Musk. The current cost for a F9 launch is 60 million (or so). So the propellant cost is pretty much irrelevant. So I don't get what this article is aiming at.
No, the price for launching an F9 is $60 million or so. The cost is less.
No, the price for launching an F9 is $60M or so. The cost is more.

So SpaceX loses money on every launch? That doesn't sound right.

Offline A_M_Swallow

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So SpaceX loses money on every launch? That doesn't sound right.

SpaceX includes a contribution to its fixed costs in the price of a launch.  So SpaceX will have to launch a minimum number of times each year just to break even.

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