Biggest problems with interstellar human flight

Originally posted by Wheely
Interstellar travel has almost happened anyway. Both Voyager 1 and 2 have crossed the heliosphere boundary. Just a little further to go and they will be in the interstellar medium.

Pioneer 10 should make Alderberan in about 20 million years. No problem!

The whole rocket thing just doesn´t work. Can you imagine a generation ship or a forty year round ...[text shortened]... rocket and we had probably better get a good idea of whats there before we attempt the journey.

reasonably useful interstellar travel. humans might not live for another 200 hundred years, we would need to get somewhere faster than that

Originally posted by Zahlanzi
reasonably useful interstellar travel. humans might not live for another 200 hundred years, we would need to get somewhere faster than that

Not nessercerily, the bet on amoungst medical/genetic reasurchers is not whether the first person to reach 1000yrs old has been born, but how old they are. takeing 200yrs to get to where your going in that context is entirely reasonable.

Also you keep stating that you need/would want an electrically charged surface for collecting AM particles. This would be a bad idea, since an oppositely charged particles would rush towards your collecting surface and impact into it.

I thought about that, for example, protons have a positive charge.
So anti-protons have negative charge. So if you charge the mesh with positive charge, negative charges will be attracted inwards and positive charges repelled. That's half the battle right there. But inside the mesh, the particles that make it though the electric sieve are all negative charges. In this case, they are not opposite charges, they will not attract each other electrically, they are LIKE charges, they will self repel, so the next step would be to guide exact atomic weights through a magnetic sieve, something I know a LOT about. My former job was an Ion Implant field service engineer and one of the key parts of the ion implanter is the mass analysis section, where ions of a specific mass and isotope # are bent in a magnetic field to either 60 or 90 degrees exactly. Other masses either are bent too much and crank to the right or bent not enough (more mas) and tend to a straight line. In both cases, only the exact selected mass (with some caveats) makes it through the output slit of the analyser. Without that technology, the ion beam which is accelerated first to about 30 to 50 KEV would be a composite of all the junk flying around the ion source area of the machine, much like the mishmash of particles (all negative charges at that point) in a harvester. I think that is the way you get a pure AM beam which would then be steered into a small orbiting circular path. I think the dudes that made the proposal knew what they were talking about, and NASA awarded them with real money to pursue the idea. They are not stupid, but mainstream physicists.

Originally posted by googlefudge
Not nessercerily, the bet on amoungst medical/genetic reasurchers is not whether the first person to reach 1000yrs old has been born, but how old they are. takeing 200yrs to get to where your going in that context is entirely reasonable.

I think what he meant was we as a race may lose it all within the next 200 years making the idea of interstellar flight a fantasy again since we may all be just too busy trying to survive, having lost 90 percent of the human race to whatever disaster awaits us in another 100 to 200 years, ice age, super global warming, nuclear war, nuclear winter, whatever. Those possibilities are very real and it is not certain we will survive the coming crises. I think that is the gist of his statement.

Originally posted by googlefudge
Shoot a beam of AM into a Bigger beam of matter. Am annihilates some of the matter releasing lots of energy, resultant plasma shot out of back of spaceship.

Okay, I get that matter and anti-matter converts into gamma rays. Gamma rays is just another form of electromagnetic radiation. You use this gammas to, here I lost you, convert into plasma (?) and shoot it out of the rear of the rocket (?)

Again, where does plasma come into the reaction. From where do you get the plasma? As I got it, you need some matter to convrt to plasma with high intencity gamma, right? So you need matter, anti-matter and something to convert to plasma? Such as...?

Originally posted by FabianFnas
Okay, I get that matter and anti-matter converts into gamma rays. Gamma rays is just another form of electromagnetic radiation. You use this gammas to, here I lost you, convert into plasma (?) and shoot it out of the rear of the rocket (?)

Again, where does plasma come into the reaction. From where do you get the plasma? As I got it, you need some matt ...[text shortened]... ty gamma, right? So you need matter, anti-matter and something to convert to plasma? Such as...?

Such as regular hydrogen or some other gas like argon or some such, it is injected into the area the reaction takes place and hopefully absorbs some of that energy to turn it into a plasma which then shoots out the asss end of the ship but with a WHOLE lot more energy than you get with chemical rockets or fission rockets. MV^2 and all that, double the velocity, you get 4 times the kinetic energy, etc.

Originally posted by sonhouse
Such as regular hydrogen or some other gas like argon or some such, it is injected into the area the reaction takes place and hopefully absorbs some of that energy to turn it into a plasma which then shoots out the asss end of the ship but with a WHOLE lot more energy than you get with chemical rockets or fission rockets. MV^2 and all that, double the velocity, you get 4 times the kinetic energy, etc.

So you have to bring matter and antimatter, then you have to bring fuel to turn into plasma. Is this the plan?

I really have an issue with the antimatter thing. As the most explosive thing known in universe is antimatter, and only a moment of hickup in the containment system will blow everything into pure gamma, I would certainly not want to be an astronaut in this baby.

Originally posted by FabianFnas
So you have to bring matter and antimatter, then you have to bring fuel to turn into plasma. Is this the plan?

I really have an issue with the antimatter thing. As the most explosive thing known in universe is antimatter, and only a moment of hickup in the containment system will blow everything into pure gamma, I would certainly not want to be an astronaut in this baby.

On the other hand, if you want to get to 0.9C, you don't have much other choice. They would for sure take extra care with the containment system. It would be high on MY mind to monitor for sure!

Originally posted by FabianFnas
So you have to bring matter and antimatter, then you have to bring fuel to turn into plasma. Is this the plan?

I really have an issue with the antimatter thing. As the most explosive thing known in universe is antimatter, and only a moment of hickup in the containment system will blow everything into pure gamma, I would certainly not want to be an astronaut in this baby.

Ok, Antimatter anhilates on contact with its matter counterpart.

When it does this it releases energy (gamma rays).

This energy can be used to heat up more mater, and turn it into plasma (baiscaly ordinary matter which is so hot that the electrons and nuclei have parted company and are swirling around independently.

The easyist way to do this (for propulsion) is to shoot a beam of AM into a beam of ordinery matter, if there is much more matter than AM, then the matter left over (after the am has anihilated) will have been made into an extreemly hot plasma, you alow this to shoot out the back of your rocket (stoping it from going anywhere else with an open ended magnetic bottle) and you get thrust (see newton for details).
The reason the AM is usefull is the sheer amount of energy released per unit mass, wich if you wan't your spacecraft to go fast is important.

Yes storage is an issue (AM containment falior happens often in Science fiction stories) but it is not beyond the realms of the possible to store it relatively safely.

Originally posted by googlefudge
Ok, Antimatter anhilates on contact with its matter counterpart.

When it does this it releases energy (gamma rays).

This energy can be used to heat up more mater, and turn it into plasma (baiscaly ordinary matter which is so hot that the electrons and nuclei have parted company and are swirling around independently.

The easyist way to do this (f ...[text shortened]... fiction stories) but it is not beyond the realms of the possible to store it relatively safely.

Okay, now I understand everything. Time to go to the laboratory and start constructing.
Do you happen to know by any chance where I can buy some AM cheap?

The bulk of the post's have been a discussion of how it might be possible to harvest (small) amounts of AM. I'm not suggesting its currently practical or viable, just telling you how an AM drive would work if we had the stuff.

Originally posted by sonhouse
Also you keep stating that you need/would want an electrically charged surface for collecting AM particles. This would be a bad idea, since an oppositely charged particles would rush towards your collecting surface and impact into it.

I thought about that, for example, protons have a positive charge.
So anti-protons have negative charge. So if you char ...[text shortened]... warded them with real money to pursue the idea. They are not stupid, but mainstream physicists.

Ok I have looked at the company you are talking about.. They are basically sugesting using a charged plate with the same charge as the anti protons that will slow and repell them onto another plate wich will bounce them back and so on, slowing them down by variouse meathods and then I assume collecting the cloud of am that has built up in the middle (I could only find the abstrct of there article). They are not sugesting using charged plates to atract am as it would as i have said before simply anhilite on contact with the plate. It's an interesting idea, but i'd still go with magnetic fields over electric ones.

Originally posted by googlefudge
Ok I have looked at the company you are talking about.. They are basically sugesting using a charged plate with the same charge as the anti protons that will slow and repell them onto another plate wich will bounce them back and so on, slowing them down by variouse meathods and then I assume collecting the cloud of am that has built up in the middle (I c ...[text shortened]... the plate. It's an interesting idea, but i'd still go with magnetic fields over electric ones.

I think they have to use both electric and magnetic. You can't accel or decel with magnetic fields, only steer. Magnetic fields cause moving ions to whip around the field lines, at an angle depending on the mass of the ion in question. A neutral will ignore magnetic and electric fields. So electric fields for attraction or repulsion, rejecting opposite charges and such but magnetic fields to steer particles in the direction they want them to go.

but an accelerating ion emits radiation, and thus slows down,

Originally posted by googlefudge
but an accelerating ion emits radiation, and thus slows down,

If that were the case, particle accelerators would be in big trouble, never being able to impart large velocities to beams. The fact that they are in the teravolt range of accel must mean something....