Would be opposed to nuclear powered space vehicles?

[judasmachine]

Have no fear of atomic energy
Cause none of them can stop the time

--Marley

 

[Eeezee]

Originally posted by: Number1

Originally posted by: Captante

Originally posted by: George P Burdell
The human race is fine with nuclear powered submarines and ships, so what's the deal with nuclear spaceships?

This was the first thing that I thought of ... what process of faulty logic would conclude that its fine to have Nuclear powered vessels cruising around within the Earths atomosphere, but too dangerous to have them operate outside of it? (assuming of course they arn't being built in earth orbit where they could potentially fall back to earth & contaminate huge areas)

There is no faulty logic. The problem with rockets carying nuclear material is that rockets sometime explode. The nuclear material would then get vaporised and spread over large area. This is not desirable.

Planes and submarines sometimes explode (or implode) as well and would spread nuclear material over an equally large area. Luckily for you, if the nuclear fuel were spread around the world (which is what would happen if a rocket carrying nuclear fuel exploded in the lower or upper atmosphere), your yearly radiation exposure would not increase but a noticable amount. It's really all a matter of education. The mass media has put such a stigma on the word "radiation" that everyone forgets how much average yearly radiation everyone experiences anyway. Coating the earth in a thin layer of nuclear fuel will not increase your yearly exposure. Heck, your body has naturally occurring radioactive elements in it right now that will give a much higher dose of radiation exposure than anything an exploding fuel rocket could do.

So yes, it is faulty logic that makes people feel okay about nuclear bombers and submarines but not okay about nuclear-powered spaceships. Consider this: Bombers carrying nuclear weapons can turn into a mushroom cloud, nuclear-powered rockets can not.

 

[iamaelephant]

Originally posted by: Eeezee
The poll only demonstrates how little ATOT knows about nuclear fission. The average distance between any region that an astronaut typically visits and the engine (aka nuclear reactor) is more than enough shielding room. You'd save a lot of mass from not requiring rocket propellant and the mission could go on almost indefinitely. The risks are almost nonexistant.

The poll agrees with your point.

 

[Thorny]

Originally posted by: Eeezee

Originally posted by: Number1

Originally posted by: Captante

Originally posted by: George P Burdell
The human race is fine with nuclear powered submarines and ships, so what's the deal with nuclear spaceships?

This was the first thing that I thought of ... what process of faulty logic would conclude that its fine to have Nuclear powered vessels cruising around within the Earths atomosphere, but too dangerous to have them operate outside of it? (assuming of course they arn't being built in earth orbit where they could potentially fall back to earth & contaminate huge areas)

There is no faulty logic. The problem with rockets carying nuclear material is that rockets sometime explode. The nuclear material would then get vaporised and spread over large area. This is not desirable.

Coating the earth in a thin layer of nuclear fuel will not increase your yearly exposure. Heck, your body has naturally occurring radioactive elements in it right now that will give a much higher dose of radiation exposure than anything an exploding fuel rocket could do.

It takes 1 plutonium atom to cause lung cancer. Just one. I know we experiance exposure to radiation all the time, but the amount contained in enriched uranium and especially plutonium WILL kill you. It might not be right away, but it will most certainly kill you. If your body had anything producing that magnitude of radiation in it, you'd already be dead.

That being said, a rocket carrying the reactor would be just as safe as any other, even in the event of an explosion. I'm sure NASA would pack it with extra bubble wrap and packing peanuts just to be safe.

 

[silverpig]

Originally posted by: potato28

Originally posted by: phisrow
I'd be a trifle nervous about the process of getting the fuel out of the gravity well. Plutonium ceramics for use in radiothermal generators are already used successfully; but those are designed to be intrinsically resistant to decomposition.
The big issue, though, would be shielding the crew on the nuclear craft. Alpha and Beta radiation can probably be deflected by some clever use of electromagnets; but gamma basically only responds to mass. Mass is bloody expensive to get into orbit. If you can solve that problem, though, it is certainly a useful energy source.

Consider that gamma radiation can be absorbed by 6 inches of water, and be safe for the astronauts. Plus they have all the survival baggage... it could be feasible.

Not quite. Gamma rays are high energy x-rays. Last I checked x-rays will go through a person quite easily, and we're basically several inches of water

Alpha particles are stopped by paper. Beta particles by a few sheets of aluminum foil. Gammas can be stopped by a dense packing of charged particles.(read: stuff).

 

[BrownTown]

It seems unlikely to me that an ion engine would be used given that it is much more complex and much less powerful than a simple nuclear rocket. There are several ways of doing this which are extremely powerful and efficient. One way is simply to have the radioactive material is small micro particles suspended in a fuel like liquid hydrogen. The particles are to far apart to set up a sustaining fission reaction, but what you do is pump the fuel/nuclear fuel out the rocket and the tube it goes threw right before the exhaust gets much thinner, this compresses the mixture and causes the nuclear fuel to rapidly fission heating the fuel to thousands of degrees as it leaves the exhaust. The heat of course causes the gas to expand very rapidly like in a conventional rocket, only much hotter.

 

[Gibsons]

Originally posted by: BrownTown
It seems unlikely to me that an ion engine would be used given that it is much more complex and much less powerful than a simple nuclear rocket. There are several ways of doing this which are extremely powerful and efficient. One way is simply to have the radioactive material is small micro particles suspended in a fuel like liquid hydrogen. The particles are to far apart to set up a sustaining fission reaction, but what you do is pump the fuel/nuclear fuel out the rocket and the tube it goes threw right before the exhaust gets much thinner, this compresses the mixture and causes the nuclear fuel to rapidly fission heating the fuel to thousands of degrees as it leaves the exhaust. The heat of course causes the gas to expand very rapidly like in a conventional rocket, only much hotter.

Liquids tend to have very small delta Vs, though.

A reactor will get a lot more energy out of your fissionable material, and you're going to need electricity anyway.

 

[ForumMaster]

it depends. thanks to Tiamat, (who gave me an interesting paper that he wrote on nuclear power), i don't think that current nuclear technology is dangerous. and just think about it like this: almost all american subs are nuclear powered.

i do think that's it's worth the risk.

 

[B00ne]

Originally posted by: Bateluer

Originally posted by: quentinterintino
Satellites are already powered w/ radioisotopes. I suppose this could just be an extension of that. Where did you get your data for a 90 day trip -- what propulsion system?

The documentary did not say exactly what propulsion system, just nuclear powered. This was coming form a NASA JPL Doctor, for what thats worth. I'd have to watch it again to grab his name.

To be fair, there are a number of satellites and probes powered by radioactive isotopes, which there hasn't been a single accident or issue.

The nuclear powered submarines have their reactors sealed in such a way that the sub can actually be crushed in water pressure and sink to the bottle of the ocean without cracking open. If I remember correctly, the reactor from the USS Thresher is still sitting on the bottle of the ocean?

Prolly this one

 

[B00ne]

I think too many ppl here mistake nuclear powered for electricity (aka radioisotope battery) with nuclear propulsion. Also comparing a radioisotope battery with a nuclear fission reactor is ludicrous

 

[Toastedlightly]

Misinformation FTW! How many nuclear tests have been conducted thus far? Also, we can make a hardened carrying case for the uranium so it stays together in the event of a catostrophic explosion.

 

[B00ne]

Originally posted by: Thorny


It takes 1 plutonium atom to cause lung cancer. Just one. I know we experiance exposure to radiation all the time, but the amount contained in enriched uranium and especially plutonium WILL kill you. It might not be right away, but it will most certainly kill you. If your body had anything producing that magnitude of radiation in it, you'd already be dead.

That being said, a rocket carrying the reactor would be just as safe as any other, even in the event of an explosion. I'm sure NASA would pack it with extra bubble wrap and packing peanuts just to be safe.

Plutonium wouldnt even need to radioactive to kill you. It is very toxic - the radioactivity is just for extra pain bonus

edit: nevermind, the toxicity seems to be exaggerated

 

[silverpig]

Originally posted by: Toastedlightly
Misinformation FTW! How many nuclear tests have been conducted thus far? Also, we can make a hardened carrying case for the uranium so it stays together in the event of a catostrophic explosion.

Something like 3000 or so IIRC. About 1000 above ground if I'm not mistaken.

 

[Pacemaker]

http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29
http://www.astronautix.com/lvfam/orion.htm

They were going to but the nuclear test ban destroyed the project.

Dyson and the other believers thought they could land a huge manned expedition on Mars by 1964 and tour the moons of Saturn by 1970.

 

[DrPizza]

1 atom of plutonium is *not* likely to cause cancer. It takes significantly more than 1 atom. "Dr. Donald Geesaman, an authority on plutonium hazard, has estimated that there will be one human lung cancer for every 10,000 fine particles of plutonium inhaled. Dispersed as fine insoluble particles (about one micron in diameter), one pound of plutonium-239 represents the potential for some nine billion human lung cancer doses."

I'm not going to look for more sources; that came from an anti-nuclear source, so I'll consider it to be a worst case scenario. While it sounds like a lot of cancer doses, you need to realize the incredible number of atoms in a pound. (454 grams per pound, 239 grams of plutonium = 1 mole = 6.023 x 10^23 atoms; 1 pound worth of atoms divided by 9 billion human lung cancer doses gives about 127,000,000,000,000 atoms. That's not a lot of atoms when you're talking about tangible quantities of a substance; however, it's a far cry from 1.

 

[Thorny]

Originally posted by: DrPizza
1 atom of plutonium is *not* likely to cause cancer. It takes significantly more than 1 atom. "Dr. Donald Geesaman, an authority on plutonium hazard, has estimated that there will be one human lung cancer for every 10,000 fine particles of plutonium inhaled. Dispersed as fine insoluble particles (about one micron in diameter), one pound of plutonium-239 represents the potential for some nine billion human lung cancer doses."

I'm not going to look for more sources; that came from an anti-nuclear source, so I'll consider it to be a worst case scenario. While it sounds like a lot of cancer doses, you need to realize the incredible number of atoms in a pound. (454 grams per pound, 239 grams of plutonium = 1 mole = 6.023 x 10^23 atoms; 1 pound worth of atoms divided by 9 billion human lung cancer doses gives about 127,000,000,000,000 atoms. That's not a lot of atoms when you're talking about tangible quantities of a substance; however, it's a far cry from 1.

You sir, seem to be correct. It is one microgram that CAN cause cancer, and not with certainty. Looks like one atom won't do jack.

 

[Savij]

ATOMS!? NOT IN MY HOUSE!

 

[sao123]

lol.... the space shuttle has been destroyed twice... each dropping tons of toxic coolants, lubricants, fuels, battery cells, insulation, and other harmful materials over 20,000 square miles of populated land & water.... and your all worried about 60kg of plutonium...


you're more likely to get lung cancer from changing the vacuum cleaner bag...