new propulsion?

[flyboy]

have we come up with any propulsion to use in space yet besides rockets or ion engines?if not y?

[ecoli]

yes, just throw something in the opposite direction that you want to go.

[bascule]

Be sure to check out the University of Washington's Advanced Electric Propulsion program, namely Mini-Magnetospheric Plasma Propulsion (a variant upon the solar sail idea)

[Klaynos]

solar sails...

[RyanJ]

solar sails...

 

A fussion engine is not considred neither an ion nor a rocket drive.

 

Cheers,

 

Ryan Jones

[Sisyphus]

There's the Bussard ramjet, which is probably how the first interstellar spacecraft will be propelled. It involves using a magnetic field to "scoop" the ionized molecules of interstellar hydrogen into a fusion engine, converting it to helium and providing thrust. It would have to already be moving very fast in order for it to sustain a reaction, but once its going, the fuel source is unlimited, and acceleration only increases as it gets faster. Google "bussard ramjet" for more info.

 

http://www.daviddarling.info/encyclopedia/I/interstellar_ramjet.html

[[Tycho?]]

There's the Bussard ramjet' date=' which is probably how the first interstellar spacecraft will be propelled. It involves using a magnetic field to "scoop" the ionized molecules of interstellar hydrogen into a fusion engine, converting it to helium and providing thrust. It would have to already be moving very fast in order for it to sustain a reaction, but once its going, the fuel source is unlimited, and acceleration only increases as it gets faster. Google "bussard ramjet" for more info.

 

http://www.daviddarling.info/encyclopedia/I/interstellar_ramjet.html[/quote']

 

Wasn't there a paper a little while ago that said drag from the intersteller medium (the ramjets fuel) would be too great for it to be economical?

[flyboy]

i thought drag dousnt matter in space if it is weightless and dont ion engines take a HUGE amount of time before they really get up to speed?

[[Tycho?]]

i thought drag dousnt matter in space if it is weightless and dont ion engines take a HUGE amount of time before they really get up to speed?

 

Ion engines are extremely efficient but provide only a small amount of thrust.

 

A Bussard ramjet would work by collecting intersteller hydrogen with a powerful magnetic field. Space isn't totally empty, even between starts. There is about 1 hydrogen atom per cubic meter, on average. Which isn't a lot. So the ramjet projects this magnetic field to collect the hydrogen, so it can be fused and used as fuel. Basically getting your fuel while you move. But if you're collecting these atoms, it means they are also slowing you down a bit. The paper I was talking about said the drag caused when collecting the hydrogen would be greater than the thrust gained from fusing the hydrogen.

 

This could be wrong though, I might be thinking of something else.

[RyanJ]

']

This could be wrong though' date=' I might be thinking of something else.[/quote']

 

It actually depends ont ehs peed you are traeling but the size of the magnetic field would havr to be massive in any case, we'r talking the size of a planet to be able to get enough fule to power the drive!

 

Cheers,

 

Ryan Jones

[Dave]

Another slightly more... unrealistic option is something called the nuclear pulse engine. Well, it's not so much an engine as a crude way of travelling via nuclear fission explosions.

 

Basically you fit a great big lead plate to the back of your spaceship. The idea is to chuck nukes out the back of the spaceship and detonate them in fairly close proximity to the spaceship. The force of the explosion contacts the ablative lead and you get a fair bit of acceleration.

 

Clearly there are some problems with this - making sure your entire crew doesn't die from radiation poisoning, for a start - but it's a good idea in theory

[RyanJ]

Another slightly more... unrealistic option is something called the nuclear pulse engine. Well' date=' it's not so much an engine as a crude way of travelling via nuclear fission explosions.

 

Basically you fit a great big lead plate to the back of your spaceship. The idea is to chuck nukes out the back of the spaceship and detonate them in fairly close proximity to the spaceship. The force of the explosion contacts the ablative lead and you get a fair bit of acceleration.

 

Clearly there are some problems with this - making sure your entire crew doesn't die from radiation poisoning, for a start - but it's a good idea [i']in theory[/i]

 

I've heareed of that one form a book called the science in science fiction, its an interesting idea and its one of only 2 good uses for nuclear devices

 

Like dave said the hard part will be the shielding and the fact that currently nuclear devices cannot be detonated in orbit.

 

Cheers,

 

Ryan Jones

[calbiterol]

Another slightly more... unrealistic option is something called the nuclear pulse engine. Well' date=' it's not so much an engine as a crude way of travelling via nuclear fission explosions.

 

Basically you fit a great big lead plate to the back of your spaceship. The idea is to chuck nukes out the back of the spaceship and detonate them in fairly close proximity to the spaceship. The force of the explosion contacts the ablative lead and you get a fair bit of acceleration.

 

Clearly there are some problems with this - making sure your entire crew doesn't die from radiation poisoning, for a start - but it's a good idea [i']in theory[/i]

 

Actually, there's been significant work on this, and it's completely practical. Quite literally the ONLY thing stopping us from building one of these right now (aside from the money/motivation to build one) is the outcry of environmentalists. In reality, there would be no environmentally adverse effects - there are far more dangerous particles already in space (including radioactive ones) that are already being filtered out by the atmosphere and magnetic field.

 

The technology has been proven as well. Both experimental results and mathematical models have been produced. It's not really unrealistic in any way, IMHO. Many of the experiments were conducted to prove that something can survive the power of a nuclear explosion and be propelled by it. The results are quite compelling. In short, they launched various constructs to "some distance away" (project orion). The wikipedia article on nuclear propultion is here. It's quite comprehensive. Check out the other articles it links to as well.

 

Ryan, out of curiosity, why can't nuclear devices be detonated in orbit? Extremely low orbit is understandable (fallout would kill people), but from an orbit as removed as the moon's?

[RyanJ]

Ryan' date=' out of curiosity, why can't nuclear devices be detonated in orbit? Extremely low orbit is understandable (fallout would kill people), but from an orbit as removed as the moon's?[/quote']

 

This may show you why: http://encarta.msn.com/encyclopedia_761553064_3/Arms_Control.html

 

All I know is they they cannot be detonated in orbit, as of yet no distance limit has been set.

 

Cheers,

 

Ryan Jones

[calbiterol]

I meant environmental/scientific issues - I was aware of that treaty, I assumed when you said orbit that you meant exclusively orbit, and not space in general. My mistake. So, to rephrase my question, are you aware of any non-political reasons why nukes couldn't be detonated in orbit?

[RyanJ]

I meant environmental/scientific issues - I was aware of that treaty, I assumed when you said orbit that you meant exclusively orbit, and not space in general. My mistake. So, to rephrase my question, are you aware of any non-political reasons why nukes couldn't be detonated in orbit?

 

As long as theyare sufficient distance from the Earth not to have the material pulled back by the Earths gravity ther eis no other reason I cna think of

Cheers,

 

Ryan Jones

[5614]

If we detonated a nuke in orbit then a significant part of the radiation released would come to Earth.

[CanadaAotS]

yes but like calbiterol said, our atomsphere already filters out more dangerous radiation then what comes out of a nuke.

 

as long as the orbit was far enough away from earth, most of the fallout would never reach earth. Our sun is like a continous nuclear explosion to begin with, a little man made nuke would be nothing compared...

 

(like I said though, as long as its a high orbit).

[Sisyphus]

Does anybody have any links to studies of what the actual impact would be for this? Obviously it has to do with proximity, but aside from that, how much shielding would the atmosphere actually provide?

[RyanJ]

yes but like calbiterol said, our atomsphere already filters out more dangerous radiation then what comes out of a nuke.

 

I'm not shure its really the radiation that would be the preoblem but the radioactive particles that would be rained upon the Earth.

 

Given sufficient distance the Earths gravity will be too week to do this and the atompsohere cna finter out nearly all of theradiation so there should be no problems.

 

Something tells me that these particles will eb charged by the solar wind and so would be repelled by the magnetic fileds of the Earth and so the hghest concentrations of particles would pobably be at the poles.

 

Cheers,

 

Ryan Jones

[Edtharan]

You could use something called the Dynamic Casimir effect.. It works similar to the standard casimire effect, however you use a single plate and move it is a certain way and it will produce a net thrust in one direction.

 

This is still thoretical and has only been demonstrated mathamaticaly. The thrust, however is very small and not useful. The scientists that discovered this effect did say that their design could be greatly improved upon and so more thrust could be generated.

 

this engine would have no fuel, however, you would need some kind of energy (electricity?) to move the plate.

[RyanJ]

this engine would have no fuel' date=' however, you would need some kind of energy (electricity?) to move the plate.[/quote']

 

You would yes but I'm shure that could be derrived from one of the other ideas here, this sounds something like a solar sail without the solar part

 

Cheers,

 

Ryan Jones