hydrogen/chemical rockets are extremely wasteful

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Woggles

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Re: hydrogen rockets are extremely wasteful

orienteer":1q7ycuik said:
Last time I checked the nuclear bomb creates the largest increase in volume with the least material, therefore controlling said reaction would indeed supply the thrust needed.
How could a nuclear chain reaction be controlled to support the theory for liftoff?

also

Just wondering if we have detected uranium in the solar system such as the moon that could be used?
 
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Swampcat

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Re: hydrogen rockets are extremely wasteful

Woggles":384zg9o8 said:
How could a nuclear chain reaction be controlled to support the theory for liftoff?
Think "Pusher Plate." See Project Orion.

also

Just wondering if we have detected uranium in the solar system such as the moon that could be used?
From Next Big Step:

An estimate of 600 trillion tons or 12 times the amount in the earth's crust for Uranium not in the Sun in the solar system.
Other sources suggest that the Moon contains anywhere from hundreds to thousands of ppm of Uranium depending on location.
 
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Woggles

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Re: hydrogen rockets are extremely wasteful

Thanks Swampcat

Both are very interesting reads!!
 
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nec208

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Re: hydrogen rockets are extremely wasteful

It should be noted however, that my original post was loaded with sarcasm towards Nec and his ideas of lifting large objects away from Earth with photon streams and Vasimr engines
What was sarcasm about my post?


I was reading that 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 once in space they can produce this small thrust for a very long time thus almost trevel at the speed of light.But it will take months if not years before they can go that fast .


Well chemical rocket have high thrust but use up the fuel very very very fast .So cannot go faster than the speed of sound.If there was fuel every where they could travel at the speed of light.But they use up the fuel too fast.Also people say Ion rockets or plasma rockets are good for long trevel but not good for short trevel.And chemical rocket are good for short trevel but not long travel.

Not sure about nuclear or fusion .
 
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Polishguy

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Re: hydrogen rockets are extremely wasteful

nec208":2wdyg4d3 said:
It should be noted however, that my original post was loaded with sarcasm towards Nec and his ideas of lifting large objects away from Earth with photon streams and Vasimr engines
What was sarcasm about my post?


I was reading that 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 once in space they can produce this small thrust for a very long time thus almost trevel at the speed of light.But it will take months if not years before they can go that fast .


Well chemical rocket have high thrust but use up the fuel very very very fast .So cannot go faster than the speed of sound.If there was fuel every where they could travel at the speed of light.But they use up the fuel too fast.Also people say Ion rockets or plasma rockets are good for long trevel but not good for short trevel.And chemical rocket are good for short trevel but not long travel.

Not sure about nuclear or fusion .
Fusion spacecraft, as I understand them (running a fusion reaction and letting some exhaust gas out like a rocket), seem to operate like ion drives but I'm not sure how much thrust they create. Nuclear Thermal has high ISP (compared to chemical) but has lower thrust. The only system that has both high thrust and high specific impulse is the one that no one is going to let NASA build, and that's Project Orion.

Oh, and I do believe that chemical rockets go faster than sound. ;)
 
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nec208

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Re: hydrogen rockets are extremely wasteful

Fusion spacecraft, as I understand them (running a fusion reaction and letting some exhaust gas out like a rocket), seem to operate like ion drives but I'm not sure how much thrust they create. Nuclear Thermal has high ISP (compared to chemical) but has lower thrust. The only system that has both high thrust and high specific impulse is the one that no one is going to let NASA build, and that's Project Orion.

Oh, and I do believe that chemical rockets go faster than sound
So nuclear or fusion have low thrust but the project orion have high thrust ?If so nuclear or fusion could never lift anything from earth do to the low thrust .
 
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Piratejoe

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Re: hydrogen rockets are extremely wasteful

Yes what others have been saying, Chemical Rockets have a huge thrust but burn out very quickly, ION engines have very low thrust but require very little fuel or equipment and Nuclear rocket engines also have low thrust but a bit more then ION engines. With a Nuclear engine the advantage in space is the constant low thrust quickly adds up overtime to achieve great speeds (great being relative). I live in New Mexico and I remember many many years ago they were testing out a Nuclear rocket and one of the problems we had here was the radiation that came from the rocket when it was being used. Now they might be able to create a Nuclear rocket today that does not Irradiate everything around it but do we really want to take those risks? In Outerspace however radiation is already their and one of the things the rocketship should be made to protect against, but on the earth it's a disaster.
 
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tanstaafl76

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Re: hydrogen rockets are extremely wasteful

Chemical rockets are the worst form of propulsion except for all the other kinds that have been tried.
 
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Polishguy

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Re: hydrogen rockets are extremely wasteful

nec208":2o8ldab6 said:
Fusion spacecraft, as I understand them (running a fusion reaction and letting some exhaust gas out like a rocket), seem to operate like ion drives but I'm not sure how much thrust they create. Nuclear Thermal has high ISP (compared to chemical) but has lower thrust. The only system that has both high thrust and high specific impulse is the one that no one is going to let NASA build, and that's Project Orion.

Oh, and I do believe that chemical rockets go faster than sound
So nuclear or fusion have low thrust but the project orion have high thrust ?If so nuclear or fusion could never lift anything from earth do to the low thrust .
Well, that's the real question. No one has ever built a fusion rocket, so without tests, we'll never know how much thrust it produces. And Project Orion had a close relative, called Project Daedalus, which would cause fusion reactions inside a rocket combustion chamber, but in pulses. It was half-Orion, half-Fusion Rocket. I guess Daedalus could have produced as much thrust as Orion, but until we actually build something, can we really tell?
 
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nec208

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Re: hydrogen rockets are extremely wasteful

Well, that's the real question. No one has ever built a fusion rocket, so without tests, we'll never know how much thrust it produces. And Project Orion had a close relative, called Project Daedalus, which would cause fusion reactions inside a rocket combustion chamber, but in pulses. It was half-Orion, half-Fusion Rocket. I guess Daedalus could have produced as much thrust as Orion, but until we actually build something, can we really tell?
No I was just saying may be plasma or fusion but I know that know one has built or tested a plasma or fusion ..I my self really do not understand how a plasma or fusion will work.It just people say in the future we may use plasma or fusion .

No I did not know that plasma or fusion have low thrust but high specific impulse.No I did not know that plasma or fusion there is not enough thrust to lift the rocket off the ground.
 
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nec208

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Re: hydrogen rockets are extremely wasteful

Well, that's the real question. No one has ever built a fusion rocket, so without tests, we'll never know how much thrust it produces. And Project Orion had a close relative, called Project Daedalus, which would cause fusion reactions inside a rocket combustion chamber, but in pulses. It was half-Orion, half-Fusion Rocket. I guess Daedalus could have produced as much thrust as Orion, but until we actually build something, can we really tell
I really do not understand how Project Orion or Project Daedalus works.
 
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rockett

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Re: hydrogen rockets are extremely wasteful

nec208":2d4uy4ce said:
Well, that's the real question. No one has ever built a fusion rocket, so without tests, we'll never know how much thrust it produces. And Project Orion had a close relative, called Project Daedalus, which would cause fusion reactions inside a rocket combustion chamber, but in pulses. It was half-Orion, half-Fusion Rocket. I guess Daedalus could have produced as much thrust as Orion, but until we actually build something, can we really tell
I really do not understand how Project Orion or Project Daedalus works.
To answer your question it is very simple:
1. Build a REALLY THICK METAL PLATE
2. Mount MASSIVE SHOCK ABSORBERS on it
3. On that build a VERY STRONG and WELL SHIELDED spacecraft (never mind the weight)
4. Throw a 1.5 to 35 kt nuclear (thermonuclear for Daedalus) BOMB about 200 ft (60 m) behind it (depending on mass of the above)
5. Detonate the thing
6. Repeat #4 and #5 about once a second

"Guarantee you, that sucker will MOVE! " (to quote a science fiction author, Niven or Pournelle I think)

http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)
 
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nec208

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Re: hydrogen rockets are extremely wasteful

That me say this again plasma propulsion,antimatter propulsion ,laser propulsion, fusion propulsion , ion propulsion or fission does not deal with the problem .They all have low thust and high inpulse and can never lift any thing from earth!!!Only the orion project and daedalus project have high thrust and high inpulse .

none of the above propulsion bring the cost down and none of the above propulsion deal with fact it TAKE MORE fuel than the payload :eek: :eek: just to lift 10% of the rocket into space and shedding the 90% empty fuel tank.

None of the above propulsion was a replacement to chemical rockets but to travel almost the speed of light.We still have problem that going in space cost lots and lots of money and fuel will be a big problem and it TAKE MORE fuel than the payload .None of the above propulsion will lift any thing from earth into space.


The rocket is like a big cruise ship just to move payload like small car in space.
 
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rockett

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Re: hydrogen rockets are extremely wasteful

nec208":tu8beqab said:
That me say this again plasma propulsion,antimatter propulsion ,laser propulsion, fusion propulsion , ion propulsion or fission does not deal with the problem .They all have low thust and high inpulse and can never lift any thing from earth!!!Only the orion project and daedalus project have high thrust and high inpulse .

none of the above propulsion bring the cost down and none of the above propulsion deal with fact it TAKE MORE fuel than the payload :eek: :eek: just to lift 10% of the rocket into space and shedding the 90% empty fuel tank.

None of the above propulsion was a replacement to chemical rockets but to travel almost the speed of light.We still have problem that going in space cost lots and lots of money and fuel will be a big problem and it TAKE MORE fuel than the payload .None of the above propulsion will lift any thing from earth into space.


The rocket is like a big cruise ship just to move payload like small car in space.
Not true:
Laser propulsion is being worked on by Lightcraft and shows a lot of promise.
http://en.wikipedia.org/wiki/Lightcraft
http://www.lightcrafttechnologies.com/technology.html

As for the rest:
plasma propulsion -true at this time
antimatter propulsion -we can't even produce this in quantity, so there is no way of knowing, theoretically possible
fusion propulsion - used by Daedelus, http://en.wikipedia pulsed nuclear.org/wiki/Nuclear_pulse_propulsion, other than that we have yet to create a sustained fusion reaction, so once again, we don't know
ion propulsion - true
fission - Project Orion pulsed nuclear

What you don't mention is other types of rockets including solid, kerosene, and aluminum water
 
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nec208

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Re: hydrogen rockets are extremely wasteful

Even if laser propulsion ,antimatter propulsion ,fusion propulsion or fission propulsion have high thrust and high inpulse I don't think the thrust would be higher than chemical propulsion .

And fusion propulsion and fission propulsion needs large rocket where 95% of the rocket is the core.
 
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nec208

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Re: hydrogen rockets are extremely wasteful

((( The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) is an electro-magnetic thruster for spacecraft propulsion. It uses radio waves to ionize and heat a propellant and magnetic fields to accelerate the resulting plasma to generate thrust. It is one of several types of spacecraft electric propulsion systems. )))


It uses radio waves to heat a propellant and magnetic fields confine the plasma.

To bad it has low thrust but high specific impulse ..
 
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Polishguy

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Re: hydrogen rockets are extremely wasteful

nec208":2irz1dhg said:
And fusion propulsion and fission propulsion needs large rocket where 95% of the rocket is the core.
Bull.

Fission Orion propulsion would have half the starting mass of the ship be payload, not core. That's far more than Shuttle or Saturn could achieve.

As an added benefit, unlike current chemical rockets (except the proposed X-33/Venturestar, which would have been fully reusable), Orion would have been an SSTO reusable vehicle. That would solve the wastefulness.

Though this does make me wonder, why exactly did NASA cancel the X-33/Venturestar?
 
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EarthlingX

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Re: hydrogen rockets are extremely wasteful

Polishguy":17906xbf said:
nec208":17906xbf said:
And fusion propulsion and fission propulsion needs large rocket where 95% of the rocket is the core.
Bull.

Fission Orion propulsion would have half the starting mass of the ship be payload, not core. That's far more than Shuttle or Saturn could achieve.

As an added benefit, unlike current chemical rockets (except the proposed X-33/Venturestar, which would have been fully reusable), Orion would have been an SSTO reusable vehicle. That would solve the wastefulness.

Though this does make me wonder, why exactly did NASA cancel the X-33/Venturestar?
List of Multiple Threads on the Same Topic
 
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nec208

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Re: hydrogen rockets are extremely wasteful

Polishguy":3rvpsj16 said:
nec208":3rvpsj16 said:
And fusion propulsion and fission propulsion needs large rocket where 95% of the rocket is the core.
Bull.

Fission Orion propulsion would have half the starting mass of the ship be payload, not core. That's far more than Shuttle or Saturn could achieve.

As an added benefit, unlike current chemical rockets (except the proposed X-33/Venturestar, which would have been fully reusable), Orion would have been an SSTO reusable vehicle. That would solve the wastefulness.

Though this does make me wonder, why exactly did NASA cancel the X-33/Venturestar?
Can you or some one explain this with out the jargon.I don't understand rockets enough to understand your reply.
 
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SteveCNC

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Re: hydrogen rockets are extremely wasteful

well for travel in space far away from anything living you might could use a nuclear engine I suppose although there might be better ways with less potential bad stuff . I've read about the possible nuclear drive before a long time ago though I can't recall where but it was most likely popular science . A much better way these days is to use nuclear power to create electric power to run a plasma drive . It would be safer and less potentially harmful side effects to others around you . There's still a need to carry hydrogen that's burned but just a little goes a long ways in a plasma engine .

There is one thing that makes me question whether a nuclear drive engine would even work is , when a nuclear bomb is detonated is uses critical mass to do so (if I remember my bombs right) and it takes an explosion to create a bigger explosion . So with that in mind I don't see it working as easy as you might think . Basically what I mean by critical mass is you can only have a nuclear explosion that's just so small (still pretty big to be used as a drive IMO ) . And as to being able to set off a nuclear explosion at pretty much any rate that means something is dubious as well .
 
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WannabeRocketScientist

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Re: hydrogen rockets are extremely wasteful

MeteorWayne":nlkn1p2h said:
Reality check here...NO NUCLEAR PROPULSION METHOD IS GOING TO LIFT A VEHICLE FROM THE SURFACE!
Would it not be possible to build a nuclear space plane, having it accelerate to the point it could escape the Earth's atmosphere and get into orbit? I suppose its not feasible now, but with things like Space Ship Two and other space plane concepts, I feel that this would be safe and effective.
 
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EarthlingX

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Re: hydrogen rockets are extremely wasteful

Perhaps something like this :

from nextbigfuture.com : Dense Plasma Focus (DPF) Fusion Systems for Space Propulsion
There were a studies published in 2006 and 2008 that looked at making a fusion rocket using dense plasma focus and air-breathing MHD propulsion. These system proposals would work even if Lawrenceville Plasma physics does not succeed with dense plasma focus fusion and does not include the weight improvements of better ultracapacitors that appears to be likely in the next five years.

from adl.serveftp.org : Advancements in Dense Plasma Focus (DPF) for Space Propulsion (pdf)


The required pulse power, energy, and voltage are 800 MW, 80 MJ, and 400 kV. The estimated DPF mass is 16 tons. An increase in Isp will heighten the payload capacity of a mission, making an increase in Isp desirable. For instance, to increase the specific impulse to 2000 s, the mass propellant mass flow rate would need to be decreased by 55% and the bank energy increased to 120 MJ. The corresponding DPF mass is approximated to be 24 tons. Similarly, for a 1000 kN thrust level, with an Isp of 2000 s, the DPF mass would be 48 tons. Lower thrust levels and higher specific impulses can be obtained by varying.
from presentation in the article :
 
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JonClarke

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Re: hydrogen rockets are extremely wasteful

All this drawing up of space planes concepts using fusion is a tad premature since we don' have cotrolled fusion even in the laboratory.
 
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JonClarke

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Re: hydrogen rockets are extremely wasteful

Polishguy":100ypfw8 said:
Fission Orion propulsion would have half the starting mass of the ship be payload, not core. That's far more than Shuttle or Saturn could achieve.

As an added benefit, unlike current chemical rockets (except the proposed X-33/Venturestar, which would have been fully reusable), Orion would have been an SSTO reusable vehicle. That would solve the wastefulness.
At the cost of widespread fall out. There is no place on earth where ground launching of Orion would be acceptable.

Also at the cost of EMP potentially wiping out a cosiderable proporition of the world's satellites and distrupting electronics for a wide swath on either side of the launch track.

Not to mention reducing the life expectancy of surviving satellites through increased radiation levels in the magnetosphere.
 
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Polishguy

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Re: hydrogen rockets are extremely wasteful

nec208":39s0yful said:
Polishguy":39s0yful said:
nec208":39s0yful said:
And fusion propulsion and fission propulsion needs large rocket where 95% of the rocket is the core.
Bull.

Fission Orion propulsion would have half the starting mass of the ship be payload, not core. That's far more than Shuttle or Saturn could achieve.

As an added benefit, unlike current chemical rockets (except the proposed X-33/Venturestar, which would have been fully reusable), Orion would have been an SSTO reusable vehicle. That would solve the wastefulness.

Though this does make me wonder, why exactly did NASA cancel the X-33/Venturestar?
Can you or some one explain this with out the jargon.I don't understand rockets enough to understand your reply.
Alright, here you go. Project Orion was an Air Force/DARPA study in the 1950s and early 1960s on using atomic bombs to propell spacecraft. The principle is like setting off firecrackers under a tin can; the force of the blast propels the spacecraft. A massive spacecraft, weighing hundreds of tonnes, is built of steel on the earth's surface at Jackass Flats, Nevada. The base of it is a steel plate, the Pusher. It has either a hole in the middle or two launchers on either side. Their purpose is to fire atomic bombs behind the plate. The blast propells the Orion forward. On any given Orion design, no matter what size, the bombs are never more than a total of 1/3 the starting mass of the spacecraft, and another third for the structure itself (the steel is for strength and radiation protection for crew. The final third is the payload (Crew, cargo, etc.)

SSTO means Single Stage To Orbit. The whole spacecraft goes up in one launch, as opposed to Shuttle and Saturn and other chemical boosters, which throw empty fuel tanks and engines off to save weight. This makes Orion totally reusable, where chemical boosters have yet to achieve two-stage reusability.

The X-33/Venturestar was a NASA/Lockheed program to develop a chemical SSTO with a 20 tonne payload. It would have been all hydrogen/oxygen powered, automated, and been able to fly numerous times a week. It was cancelled in 2001 when the prototype was largely completed.

If there are spelling errors, I'm sorry. My broser's glitching and I can't look at the line I'm typing.
 
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