hydrogen/chemical rockets are extremely wasteful

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rcsplinters

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Re: hydrogen rockets are extremely wasteful

Some of us have been watching too much Star Trek and weren't paying close attention in Physics class.

Pretty simple concepts from a physics point of view. You have several tons of crew and lifesupport craft to toss at about 17.5 kmph. It takes a certain amount of energy to get that to happen and nothing can change that. Blame Mr Newton, not my rules. Add the weight of fuel to do that and you have to have energy to move that. More fuel, more energy. You back up till the equation balances and you have a lot of big hardware that carries mostly fuel. The heavier the orbital load, the bigger the beast becomes. Hence, HLV is the single most critical element for beyond LEO travel, darn astronauts, sorry cosmonauts, just insist on breathing and eating (go figure) so it takes a lot of "stuff".

Now, there's one other aspect of this we have to consider. It is considered very desirable for your astro, errr, cosmonauts to be in roughly the same physical form when they get to orbit. Liquified astronauts are very limited assets in orbit. This means we have to expend this tremendous energy over time in a VERY controlled fashion. Breaking chemical bonds provides the amount of energy required and can be precisely controlled. All these thoughts on exotic propulsion might show promise in orbit or over long distances far from the strong force of gravity. However, going 0 - 17.5 kmph through a thick atmosphere starting in a 1g field, you better have a lot of energy and you better be able to control it.

I think these very simple observations lead one to understand why the current plan is nothing but folly. There are no miracle technologies just over the horizon for HLV. We need a 100 tons or more capability and the options in 5 years are going to be about what they are now. This waiting is politics and NOT science. It shameful.
 
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scottb50

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Re: hydrogen rockets are extremely wasteful

rcsplinters":3bqc4k3f said:
Some of us have been watching too much Star Trek and weren't paying close attention in Physics class.
Hydrogen and Oxygen provide the highest ISP from conventional propellants. Even with storage considerations they are as cost effective, or more so, as other propellants. For a heavy lift no other combination makes sense. Even a medium or smaller stage loses more efficiency with kerosene then it would have if using Hydrogen.

Hydrogen/LOX engines also have reduced wear and are much better for multiple uses.

Just the opposite of what you propose.
 
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nec208

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Re: hydrogen rockets are extremely wasteful

How many people can the Project Orion or X-33/Venturestar take up? I thought they ran into a engineering problem with the X-33/Venturestar and do to lack of money put end to it.But has of now fix the engineering problem but with the program done away with does not help.

Unless some other goverment or private sector takes on the X-33/Venturestar .

Would Project Orion almost trevel at light speed?
 
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Polishguy

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Re: hydrogen rockets are extremely wasteful

nec208":f7mxdj9c said:
How many people can the Project Orion or X-33/Venturestar take up? I thought they ran into a engineering problem with the X-33/Venturestar and do to lack of money put end to it.But has of now fix the engineering problem but with the program done away with does not help.

Unless some other goverment or private sector takes on the X-33/Venturestar .

Would Project Orion almost trevel at light speed?
Yes, it was an engineering problem for X-33. They couldn't get the hydrogen tank built before funding dried up. I heard Lockheed's doing some flight tests with a smaller concept model, but I'm not sure.

Project Orion's speed depends on fuel. Using fission (Uranium or Plutonium) explosives, it can get 5% lightspeed. Fusion (hydrogen isotopes/helium-3) can get 10% lightspeed. Antimatter/matter pulses are supposed to get up to 50% lightspeed! But that last one is not technically feasible. Still, less than a century voyage to Alpha Centauri for fusion (including the time to accelerate). Not a bad deal.
 
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rcsplinters

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Re: hydrogen rockets are extremely wasteful

scottb50":3ma05hgq said:
rcsplinters":3ma05hgq said:
Some of us have been watching too much Star Trek and weren't paying close attention in Physics class.
Hydrogen and Oxygen provide the highest ISP from conventional propellants. Even with storage considerations they are as cost effective, or more so, as other propellants. For a heavy lift no other combination makes sense. Even a medium or smaller stage loses more efficiency with kerosene then it would have if using Hydrogen.

Hydrogen/LOX engines also have reduced wear and are much better for multiple uses.

Just the opposite of what you propose.
Actually, we agree. I should have been more precise with my comment. Rearranging chemical bonds would have been a better choice of words. Hydrogen and Oxygen offer a very viable solution, obviously. That said, I think the combination of solids and cryogenics (H & O) is clearly viable as well. Bottom line is that there really aren't many reasonable options available between now and 2015 for the ride uphill.
 
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MeteorWayne

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Re: hydrogen rockets are extremely wasteful

nec208":yot6bawv said:
.

Would Project Orion almost trevel at light speed?
No, not evn 0.0001% of light speed.
 
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ZiraldoAerospace

Guest
Re: hydrogen rockets are extremely wasteful

Not to burst anyone's bubble but kerosene isn't the only hydrogen alternative. Hydrazine is bad because it is so toxic and expensive, but I have heard people pitching using methane instead of hydrogen. It is sort of a middle ground between hydrogen and RP-1 because it is a gas like H2 but it is a much denser gas. It can also be easily manufactured from manure if NASA or anybody else wanted to be less wasteful.
 
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scottb50

Guest
Re: hydrogen rockets are extremely wasteful

ZiraldoAerospace":26nt52lx said:
Not to burst anyone's bubble but kerosene isn't the only hydrogen alternative. Hydrazine is bad because it is so toxic and expensive, but I have heard people pitching using methane instead of hydrogen. It is sort of a middle ground between hydrogen and RP-1 because it is a gas like H2 but it is a much denser gas. It can also be easily manufactured from manure if NASA or anybody else wanted to be less wasteful.
Methane has considerably less energy then other fuel sources because it takes a little more energy to break the Carbon/Hydrogen bonds. As the molecules get bigger the bonds become easier to break. With hydrocarbons you can't forget the Carbon, take away the Hydrogen and it will soak up more of the Oxygen, that combinaion creates less energy then combining Hydrogen and Oxygen so the reaction is diluted and the ISP is lower. In a lot of cases that can be accepted because of storage requirements. For a launcher that isn't a big problem and since the most challenging part of operating in Space is getting there LH/LOX offer the optimum propellant.

In Space hypergolics can be stored longer and are the most reliable combination, just get them into contact and they work, no ignition needed. Probably a better route would be water and Solar power, Hydrogen and Oxygen gasses produced in small amounts as needed for thrusters and liquification, also Solar powered for longer range.
 
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EarthlingX

Guest
Re: hydrogen rockets are extremely wasteful

With LH you add unnecessary volume, which translates to drag in the atmosphere. There are also storage problems, which are not minor, and structural problems.

You also need two turbo pumps for engines, operating at different speeds, witch adds complexity. If propellant and oxidizer have about the same density, you can run them with the same shaft.

Not the best choice. More dense fuels are most likely better, and as far as i know, RP-1 engine holds the record for the best weight/thrust ratio, good old NK-33.

I wonder, if it would be possible for NASA to cooperate with Roscosmos/Energomesh on RD-191 ? Perhaps Aerojet has some strings there ?

Russians are building Angara, NASA will most likely build a 50t class heavy launcher, why not work together, and share the costs ? It seams like an option, with NASA at only half the effective budget from 1998.
 
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nec208

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Chemical rockets are extremely wasteful on fuel?

chemical rockets is extremely wasteful on fuel and have a very hard time taking up alot of payload with out a very big rocket that uses even more fuel !!!!! if you look at a NASA rocket that ENTIRE thing is carrying liquid hydrogen and liquid nitrogen all so that a handful of people and a payload of less than a 5% of the mass of the entire rocket can get into space!!

Ion rockets or plasma rockets have low thrust .So as of right now, they could never lift anything from earth do to the low thrust .But what about nuclear or fusion ? Do they have enough thrust and can they take up more payload than now ?

I will like to know can nuclear or fusion take up more payload or are they not that much better than Chemical rockets.

I hear that nuclear or fusion can take up 5 times more payload than chemical rockets is that true.

What about laser propulsion?


I'm so sick of NASA conplaining of cost ,fule and lack of payload ..
 
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RVHM

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Re: Chemical rockets are extremely wasteful on fuel?

OK, you're gonna find a solution yourself, ain't you?
 
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wick07

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Re: Chemical rockets are extremely wasteful on fuel?

nec208":36mvgd7l said:
chemical rockets is extremely wasteful on fuel and have a very hard time taking up alot of payload with out a very big rocket that uses even more fuel !!!!! if you look at a NASA rocket that ENTIRE thing is carrying liquid hydrogen and liquid nitrogen all so that a handful of people and a payload of less than a 5% of the mass of the entire rocket can get into space!!

Ion rockets or plasma rockets have low thrust .So as of right now, they could never lift anything from earth do to the low thrust .But what about nuclear or fusion ? Do they have enough thrust and can they take up more payload than now ?

I will like to know can nuclear or fusion take up more payload or are they not that much better than Chemical rockets.

I hear that nuclear or fusion can take up 5 times more payload than chemical rockets is that true.

What about laser propulsion?


I'm so sick of NASA conplaining of cost ,fule and lack of payload ..
So in one thread you make the claim that nuclear propulsion is too dangerous, and in this thread you claim that chemical propulsion is too inefficient. Do you have anything positive to add, or are you just trying to list all the ways we shouldn't go to space...
 
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MarkStanaway

Guest
Re: Chemical rockets are extremely wasteful on fuel?

The only nuclear fusion device that has been made so far is called an H bomb.

A controlled nuclear fusion device which could be used for a power plant or rocket has been about ten years in the future for the last fifty years.
 
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nec208

Guest
Re: Chemical rockets are extremely wasteful on fuel?

So in one thread you make the claim that nuclear propulsion is too dangerous, and in this thread you claim that chemical propulsion is too inefficient. Do you have anything positive to add, or are you just trying to list all the ways we shouldn't go to space...
No I'm listing the different propulsion and what is better.Well chemical propulsion has high thrust the problen is it useses the fuel up very fast .This why you need a very big rocket and lots and lots of fuel .

A propulsion that has high thrust that can be launched from earth.I know Ion rockets or plasma rockets have low thrust so cannot lift up any thing.
 
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bdewoody

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Re: Chemical rockets are extremely wasteful on fuel?

It is ludicrous to propose to use nulear rockets for heavy lift from the ground to orbit. A nuclear rocket with enough power to lift cargo or humans into orbit would spew vast amounts of radiation into the atmoshere with every launch, very bad idea.
 
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wick07

Guest
Re: Chemical rockets are extremely wasteful on fuel?

bdewoody":2pr09fhl said:
It is ludicrous to propose to use nulear rockets for heavy lift from the ground to orbit. A nuclear rocket with enough power to lift cargo or humans into orbit would spew vast amounts of radiation into the atmoshere with every launch, very bad idea.

It depends a bit on the type of nuclear rocket. A solid nuclear core would be somewhat dirty. A liquid core would be really dirty. But a gas core could possibly be clean enough to launch from Earth's surface with an acceptable level of radiation. Sadly, this concept is entirely theoretical, so for the near term you are correct, nuclear is only usable in space.

The main issue with the solid core is, that as a first stage it wouldn't provide that great of an advantage over a chemical rocket, making it mainly useful as an upper stage.

Oh, and people are scared silly by the word "nuclear".
 
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bdewoody

Guest
Re: Chemical rockets are extremely wasteful on fuel?

I think the best potential for powering spacecraft in the near future is with nuclear rockets. There is no atmosphere in space to pollute. But only space craft that are designed to remain in space for their full service life. I don't think nuclear powered craft should ever be allowed to operate in any planet's atmosphere. So chemical rockets will probably play some role in space exploration or exploitation for quite a while.
 
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tanstaafl76

Guest
Re: Chemical rockets are extremely wasteful on fuel?

Chemical rockets are the worst form of propulsion for getting to space, except for all the other kinds currently available.
 
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nec208

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Re: Chemical rockets are extremely wasteful on fuel?

tanstaafl76":1upckuq2 said:
Chemical rockets are the worst form of propulsion for getting to space, except for all the other kinds currently available.
Chemicalc propulsion are extremely wasteful on fuel .And Ion rockets or plasma rockets have low thrust so can never lift any thing from earth.

Not sure about laser propulsion .I hear that antimatter propulsion is more fuel efficient.Not sure how much better than Chemicalc propulsion.
 
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MeteorWayne

Guest
Re: Chemical rockets are extremely wasteful on fuel?

Duplicate of your own thread, merged and retitled to capture both.
 
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nec208

Guest
Re: Chemical rockets are extremely wasteful on fuel?

MeteorWayne":3lazz2k3 said:
Duplicate of your own thread, merged and retitled to capture both.

What got duplicate ?What is duplicate here?
 
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nec208

Guest
I'm having a discusses with some friends about space cost and rocket propulsion.I thought I will post some of the views tallked about and concludes that chemical rockets are the only option now and in future for taking stuff up into space.

The summary has gone like this from the 60's to now that is 50 years we are like ants just hardly making it past earth orbit in are rafts that is extremely costly and at most we gone to the moon.

Space cost does not seem to be coming done and it does not look like we will get any where in space other than the moon and mars (just to vist) with today's technology !!Well space mining and space colony is a pipe dream with today's technology.

Are there other options ( Has of now no !!! ) Please read.

- Anti-matter ( very very very costly (way more than chemical propulsion) , very hard to make and cannot be stored has fuele has we do not know how to store it yet.

-Ion or plasma does not have the thrust to lift any thing to space ( must be used for deep space not solution to get into space )

--Laser propulsion , pulse Laser very very costly and need gigawatt power.

--nuklear or fussion ( have not read up on this but the core and shielding would make it very big) not going help with payload problem.The cost to have a core and shielding may make more costly than chemical propulsion .

--nuklear Pulse very very costly to protect it from vibration to rocket.

--microwave propulsion very bad on the person health.

-- space elevator beyond todays technology !!


In the end it seems chemical propulsion is the only option to get into space.
 
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JonClarke

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Once again we have demonstrated the fact there is nothing so invincible as willful ignorance.
 
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annodomini2

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Re: hydrogen rockets are extremely wasteful

JonClarke":2zhi6dfm said:
All this drawing up of space planes concepts using fusion is a tad premature since we don' have cotrolled fusion even in the laboratory.
This statement is incorrect, we have been able to create controlled fusion reactions in the lab since the 50's.

Creating a controlled fusion reaction with a net energy benefit, has yet to be achieved.
 
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annodomini2

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nec208":1w3ypcey said:
- Anti-matter ( very very very costly (way more than chemical propulsion) , very hard to make and cannot be stored has fuele has we do not know how to store it yet.
To make 1 gramme of Anti-matter would cost the entire GDP of every nation on the planet, it is the most expensive substance known to mankind at this time.

Storing it is irrelevant if you can't afford to make it in the first place!
 
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