/sci/ - Science & Math

[Anonymous No.1931649]

why hasn't anyone figured out how to use uranium to power a rocket ship?

my understanding is launches into space are largely limited by the large fuel payload.

nuclear technology has been studied and refined over many decades for electrical power supply, how is it no one has figured out how to adapt this technology into a rocket ship?

[Anonymous No.1931665]

Because no one wants radiation raining down on their heads every time a rocket is launched.

[Anonymous No.1931673]

>>1931665
HAHAHAHAHA.

[Anonymous No.1931679]

They have, idiot. We can't use it because of the Partial Test Ban Treaty of 1963.

[Anonymous No.1931689]

why hasn't anyone figured out how to use nanotubes to build a space elevator?

my understanding is getting supplies into space is largely limited by the large fuel-wasting of using energy in direct opposition to gravity.

How is it no one has figured out how to adapt this technology into a viable bypass of the rocket ship?

[Anonymous No.1931691]

>>1931673
No one wants that much deadly radiation in the atmosphere, especially locally.

That better?

[Anonymous No.1931720]

>>1931665
>>1931691
Why would radiation be leaking out? Radiation isn't pouring out of nuclear power plants, which power 15% of the planet.

Obviously whatever technologies keep radiation from killing everything would also be implemented into space ship design.

>>1931679
Listen. Idiot. A space ship is not a weapon. Idiot.

[Anonymous No.1931733]

>>1931720
> Listen. Idiot. A space ship is not a weapon. Idiot.

Yes it is.

It just depends how long you're willing to wait for maximum damage.

3 kips is the magic number.

[Anonymous No.1931738]

>>1931720
Good luck lining a rocket with a thick wall of lead or a thicker wall of concrete. The weight to gain ratio would negate the use of nuclear power. Also, how do you suppose they use Uranium to launch a rocket? They can't use it like a power plant, because all they do there is heat water. The best I can think of is causing small nuclear blasts under the rocket pushing it up. That would cause a lot of radiation though.

[Anonymous No.1931740]

>>1931720
radiation doesn't leak out of nuclear plants because they are essentially steam engines with a nuclear reaction heating the water
how would you achieve lift with a nuclear reaction besides dumping out radiation as exhaust?

[Anonymous No.1931743]

>Listen. Idiot. A space ship is not a weapon. Idiot.
>implying you can't blow it up

[Anonymous No.1931748]

This makes me wonder? Have we figured out how to -gradually- release the energy from nuclear fusion and fission, rather than having a volatile explosion? Like, burning the fuel?

[Anonymous No.1931755]

>>1931743
cars can be blown up. are cars weapons?

[Anonymous No.1931761]

>>1931738
>The best I can think of is causing small nuclear blasts under the rocket pushing it up. That would cause a lot of radiation though.
Which is why a nuclear ship in space is fine because the radiation would be drowned out by the solar wind, and is bad in an atmosphere because the radiation would be trapped.

[Anonymous No.1931759]

>>1931748
use less uranium?

[Anonymous No.1931770]

>>1931761
In space, it is a viable method of travel. Leaving Earth, which is what OP is talking about, via that method would end up irradiating the atmosphere.

[Anonymous No.1931772]

>>1931759
>use less uranium?
Oh god, I lol'd. What do you propose the uranium be replaced with? Ponies that eat rainbows and shit butterflies? If there isn't enough energy, the rocket won't work. Period.

[Anonymous No.1931777]

>>1931772
thorium!

[Anonymous No.1931783]

>>1931772
was responding to the question:
>Have we figured out how to -gradually- release the energy
not about the rocket

to my knowledge that is how the control the reactions, when it gets too hot they put the control rods or whatever they are called in to cover some of the uranium so it doesn't participate in the reaction

[Anonymous No.1931785]

>>1931748

Try long chains of small doses of fuel, I suppose.

[Anonymous No.1931786]

you ultimately need to accelerate MASS (like liquid hydrogen/oxygen, combined together, blasting out of the back of a saturn 5, or even the detachment of the 1st or 2nd stage rockets....) to achieve spaceflight.


some of the non-physics nerds who spend way too much time reading science fiction and wikipedia articles will say:


you can use photons (light) for their momentum...


the problem is that nothing (not even the sun) will accelerate anything fast enough to escape even moderate gravity (which means you could never leave the earth's gravity)
the best bet for using nuclear power as a power source for space flight:


using it to heat up a working fluid so unbelievable hot that its pressure causes it to escape at extremely large velocities....

using it as a source of electricity to accelerate material out of the back of a "linear accelerator"
thats it. having a power source onboard a spacecraft for ANY OTHER purpose (related to movement) is worthless.


a light source on the spacecraft cannot be used to create movement (like a laser ON the spaceship)

[Anonymous No.1931791]

Rockets can fail. The history of rocketry is practically filled with spectacular failures. When it comes to these things, you build expecting at least one to explode. And what is essentially a dirty bomb in the atmosphere is simply not worth it.

Also, how the heck would you convert the resultant power into thrust? You have to vent something in space, that's just how it works.

[Anonymous No.1931793]

>>1931649
Plain and simple, heavy elements make poor fuels, and fission makes for unacceptible levels of pollution. Until fusion can be efficiently used, and heavy water and Helium-3 is used, this idea will go nowhere.

[Anonymous No.1931802]

Two major options as I see it:

You've got the project orion style direct reaction. Shit's crazy, but SO AWESOME. Seriously, imagine watching one launch. Three nukes going off A SECOND, sweet Jesus the noise. Imagine a GAU-8, but on a biblical scale. In fact biblical's too tame, It'd be on the scale of the old hindu legends where their gods weren't pussy subtle about shit and wouldn't hesitate to vaporise half a continent without warning. In any case, this is still our best bet for getting space ships hitting significant fractions of the speed of light. Cons: A bunch of people would die after every launch from the fallout. That's why the original program got shut down, well, in addition to the fuckheads at the pentagon deciding it needed guns all over it, making a mockup looking like something from an Ork WAAAAGH, showed it to JFK, who then almost threw up at the prospect.

The other possibilty is using a reactor to generate power and then feeding that to an Ion engine or using electric fields to supplement the thrust of a Chemical Rocket. Pretty much a retarded Idea unless we can figure out how to build a reactor which doesn't give off a fuckload of radiation as the shielding makes it far too heavy to be even remotely feasable. Also, Ion drives stupidly low specific impulse lol. Great if you're already in orbit, not so great for heavy lift solutions.

We totally need to restart project orion.

[Anonymous No.1931800]

>>1931793

Plus this.
>>1931689

[Anonymous No.1931798]

>>1931786
>using it to heat up a working fluid so unbelievable hot that its pressure causes it to escape at extremely large velocities....
isn't there a russian nuclear rocket that does that with hydrogen?

[Anonymous No.1931803]

>>1931793
Fusion or fission, you still have the issue that all you're making is pure energy in the form of heat. Heat alone cannot lift a rocket.

[Anonymous No.1931818]

>>1931803
Correct.

>http://en.wikipedia.org/wiki/Plasma_propulsion_engine

This would help once it's developed more.

[Anonymous No.1931825]

>why hasn't anyone figured out how to use uranium to power a rocket ship?
We have, they're called ICBMs.

[Anonymous No.1931833]

>>1931783


it is extremely unlikely (almost zero probability) that a nuclear power plant could ever explode from a nuclear reaction.


this is because the nuclear fuel itself is not dense enough for the flux of neutrons to create an uncontrolled fission chain reaction (like the process that occurs in a nuclear weapon).


the biggest concern with a nuclear power plant is that the nuclear fuel will get soooo hot that it will melt and destroy shielding equipment, and also release daughter nuclides (which are sometimes EVEN MORE reactive than the parent nucleus) into the environment (As dust, alpha particles, etc).


this is what happened at chernobyl. a big molten mass of nuclear fuel basically just melted (by itself) and flowed out of the reactor and into other parts of the power plant.


it was soo radioactive that it was emitting gamma and X-rays, as well as alpha, beta, and daughter nuclides, all over the place.
ultimately, the problem is containment. you cant just send in robots or even lead shielded humans....

nothing can stop that much radiation up close.

no electronics (robots) can handle it. humans, even when shielded by lead/tungsten and boron can withstand it.


so no one can go in and "Clean it up"


that was the ultimate problem in chernobyl, and basically required people to sacrifice their lives... (which they did).


the final solution was to simply build a concrete cover over the ENTIRE power plant (its called the "sarcophogus")

[Anonymous No.1931834]

>>1931825
nuclear powered not nuclear equipped

[Anonymous No.1931835]

>>1931825
troll or moron? Hmmmm...

[Anonymous No.1931848]

>>1931649
>nuclear technology has been studied and refined over many decades for electrical power supply
I wouldn't call steam turbines advanced by any definition

[Anonymous No.1931853]

>>1931825
w..what?

[Anonymous No.1931863]

>>1931803
>>1931818

honestly, for the purposes of little kids dreaming about going into space like in science fiction....


the ULTIMATE problem is that we need to carry our fuel along with us in order to move in space.


if we didnt have to lug along 1,000 tons of fuel, things would be different.


so either we figure out brand new physics, or we consign ourselves to the fact that space flight will ALWAYS be tremendously expensive....


and before you start waving your hands and pointing to trends in "space tourism" as an indicator of the decrease in cost....

I alert you to the fact that 100% of all space tourism related efforts, all commercial spaceflight applications (which are usually directed towards cheap satellite delivery), etc...


ALL of these projects use existing technology, optimized, with new designs, to MINIMIZE cost.


none of them are novel.

they are engineering projects. they involve NO fundamental research at all.


cheap spaceflight = off the shelf components + minimal manpower + simple mission (low earth orbit)

[Anonymous No.1931888]

>>1931848

>I wouldn't call steam turbines advanced by any definition


>doesnt realize that 95% of the energy delivered to the grid is created by a turbine of some form

>doesnt realize that 99.99% of the energy delievered to the grid is ultimately created by spinning an electric generator
there are basically 4 forms of electricity generation that are not, ultimately, limited by the carnot efficiency...


thermoelectric effect
charge separation in a semiconductor
piezoelectriceffect
electrochemistry

[Anonymous No.1931906]

>>1931888


I said limited by the carnot efficiency...


I meant that there are ultimately 4 forms of non-mechanical electricity generating processes.


they do not require/necessitate the use of any moving parts.


but everything else does:

nuclear, coal/petroleum, hydroelectric, most solar (by kwh produced), wind, geothermal, wave, etc.
the problem with nuclear is that pretty much all of its energy is produced as particles/radiation that are too energetic to recover their energy "directly" as electricity.

you could, theoretically, build what amount to "solar cells" to capture the X-rays and Gamma rays....

but the problem is that these forms of radiation will actually destroy the carefully grown crystal structure of the semiconductors that make up the solar cell.


on a related note, this exact type of effect (radiation on semiconductor crystals) is actually a major concern for satellites...


it turns out that modern satellites (like those being built at this very moment) use ANCIENT, comparitively, semiconductors.


seriously, the shit the shoot up into space right now is less advanced than a Pentium III...

anything more advanced (and with smaller feature size) is too susceptible to radiation.

[Anonymous No.1933340]

>>1931649
>why hasn't anyone figured out how to use uranium to power a rocket ship?
>my understanding is launches into space are largely limited by the large fuel payload.

Your understanding is wrong. Launches are limited by the large reaction mass payload. The fact that the reaction mass also serves as fuel is secondary.

Nuclear power might be able to reduce the amount of reaction mass by increasing its temperature and thus its speed, but you have to figure out how to make the engine withstand those temperatures. Just dealing with the temperature of chemical rockets is hard enough.

Also, unless you want to leak large amounts of radiation, you need a fair amount of shielding, which is inherently heavy. Which means that nuclear heating would only be viable for massive craft.

The most viable alternative is VASIMIR. This deals with the temperature issues by superheating the reaction mass to plasma, which allows the use of magnetic containment. Unfortunately, it's going to be a long time before they can make one big enough for launches. Currently, it's aimed at generating small amounts of thrust using very small amounts of fuel.

[Anonymous No.1933363]

>>1931755


yes

[Mr. Hyde !!cPIqDLBbmTg No.1934780]

I'm seeing a great deal of confusion in this thread, so let me clear a few things up.
There's basically two ways of using Nuclear power to run a rocket.

1. Use directional heat from the blast to power the rocket.
2. Use a nuclear reactor to power a turbine to lift the rocket.

#1 is awesome because it's relatively lightweight, easy to control, and works in space.
#1 sucks because it would spew radioactivity behind the rocket in the blast area and in the atmosphere, there are few protections against criticality, and the nuclear payload would have to be detached (dropping a radioactive 'dirty-bomb' in an unplanned location) to land.

#2 is awesome because it doesn't spew radiation everywhere
#2 sucks because you would need a COMPLETE FUCKING POWER PLANT on board to function (If I recall correctly, plans for the pre-Orion nuclear plane during the Cold War suggested such a craft would weigh over a million pounds) Also, turbines don't work in space and become less effective as altitude increases, given the mass of the object and the capability of modern turbines, it is technically impossible to launch a rocket into space using the #2 method and practically impossible to use the turbine once outer atmosphere has been gained.

So really the ONLY option that works is the one where you spew radiation everywhere. Which nobody likes because everyone would die. Also cocks.

[Mr. Hyde !!cPIqDLBbmTg No.1934791]

>>1931748
Sort of, there are two rods in a nuclear reactor, fuel rods and control rods. The purpose of control rods in nuclear reactors is to capture neutrons created by nuclear reactions. Because these neutrons are absorbed by control rods, they fail to ignite further reactions in the fuel rods.

So we have a 'slow burning' nuclear reaction. The soviets removed control rods entirely at Chernobyl. LOLOLOLOL

[Mr. Hyde !!cPIqDLBbmTg No.1934820]

>>1931761
Project Orion

>>1931772
Control rods and less uranium, to be precise.

>>1931825
Actually, ICBM's are powered by liquid hydrogen if I remember correctly. Nuke is only used for damage.

>>1931833
You are correct, sir. Though I submit that it is not nuclear explosion that most people are worried about, the cause for concern is entirely grounded in fallout and radiation leakage which damaged reactors are VERY capable of providing.

[Anonymous No.1934841]

Well you See "Nuke" power doesn't work that way. It is better used as an electrical source much like solar and Thermal.

Its use is best for Short bursts like a car battery NOT long runs like Fuel

[Anonymous No.1934845]

>>1934791
Chernobyl was a complete cluster fuck off the bat. Had they done one of a dozen basic safety procedures it would have averted it. What an embarrassment.

[Anonymous No.1934871]

>>1934845

It was also a bad design.

The control rod was tipped with the mediator. So when they extracted the control rods completely they also extracted a good portion of the mediator in the reactor.

When the thing started heating up again, and they decided to lower the control rods... Guess what went in first? The tips... with the mediator... that facilitates fission (it slows neutrons to increase the fission crosssection).

Its like having a car with one pedal that is the brake and the gas. You slam on the pedal and it decides to speed up instead.

Obviously they werent supposed to be completely withdrawn, but c- nuclear engineers didn't know shit about their reactor design.

When they actually did insert the rods, the thing went into a sudden power spike and melted the fuel and control/mediator rods, which jammed the lowering mechanism and prevented them from being lowered in completely.

[Anonymous No.1935557]

Why not keep the nukes on the ground? Have them power rail-gun-esque device strong enough to achieve orbit, eliminating the need for the craft to carry any fuel-weight beyond orbital maneuvers?

[Anonymous No.1935577]

>>1935557
>yfw over 9000 g

[Anonymous No.1935591]

>>1935557
>yfw over 9000 gee