Most likely candidate for future spaceship propulsion

[Gardamorg]

This post has been moved here.

[Moontanman]

[quote]

Originally Posted by Gardamorg

You know what would be even better?

Laser beams that are so hot and intense that they fuse and transmute matter in the back of a space craft into energy used to propel the craft.

On the face of it not a bad idea. But I have yet to see any sign of anyone having a laser even close to being that powerful.

The ship's fuel will will undergo a series of stages, first, the fuel is raw hydrogen, second, a remote laser beam fuses and heats this hydrogen into plasma, this laser beam is very powerful, and fired from a solar powered space station/operating laser canon.

As long as the ship is nearby not a bad idea.

In a few minutes, this plasma will be so hot that it will burn separate hydrogen into plasma without the need of a high powered laser, this will cause a chain reaction, the plasma will become so hot that it's atoms will release energy by themselves, and the hydrogen will become so hot that it will transmute into more plasma, which in turn will release more energy, making the craft self sustained.

This sounds like tecnobabble to me, you need to give us some idea of how this works, I know of no way to do what you are talking about. Hot atoms do not spontaneously release energy, they only have the energy the laser has pumped into them.

The problem is the fuel (hydrogen) will be burned at an abnormal rate, which is why the hydrogen will be scooped up from the interstellar medium.

Ok so you don't intend to carry your hydrgen with you?

It won't need a magnetic field because it's already moving so fast that it's speed will allow it to cover cover so much space in so little time, that it's speed compensates for the width a magfield would have to be.

How do you scoop up hydrgon if it's not charged?

It can accelerate to this speed because it doesn't need energy at all, just hydrogen, the energy is supplied by the space station that fires the laser beam which splits atoms with heat alone, and after a certain point in time it doesn't even need the laser.

A laser would only work at extreme close range, lasers spread out over time, by the time you were a few thousand miles away even the strongest laser would be spread to far to heat up anything to the extreme temps you going for. Also no amount of heat will split hydrogen atoms or any other atoms for that matter.

So this craft is in a sense, a ramjet, a laser beam powered space craft, and a self sustained fusion reactor.

It doesn't need charged hydrogen.

To pick up enough hydrogen in the way a ram jet would pick up oxygen in the atmosphere would require it to be traveling a substantial fraction of C. Accelerating to that speed would require an enormous amount of hydrogen to start with and hydrogen fusion triggered by a remote laser would not be self supporting. Even if it was how would you restart it if you had to turn it off for some reason? also how would you decelerate at the end of your trip?

[Gardamorg]

[quote=Moontanman;239107]

On the face of it not a bad idea. But I have yet to see any sign of anyone having a laser even close to being that powerful.




As long as the ship is nearby not a bad idea.





This sounds like tecnobabble to me, you need to give us some idea of how this works, I know of no way to do what you are talking about. Hot atoms do not spontaneously release energy, they only have the energy the laser has pumped into them.



Ok so you don't intend to carry your hydrgen with you?




How do you scoop up hydrgon if it's not charged?




A laser would only work at extreme close range, lasers spread out over time, by the time you were a few thousand miles away even the strongest laser would be spread to far to heat up anything to the extreme temps you going for. Also no amount of heat will split hydrogen atoms or any other atoms for that matter.



To pick up enough hydrogen in the way a ram jet would pick up oxygen in the atmosphere would require it to be traveling a substantial fraction of C. Accelerating to that speed would require an enormous amount of hydrogen to start with and hydrogen fusion triggered by a remote laser would not be self supporting. Even if it was how would you restart it if you had to turn it off for some reason? also how would you decelerate at the end of your trip?

Right on top of it, realizing this I edited the post, and moved it to the BEC thread, before you posted.

[Gardamorg]

My idea has been modified, see if it STILL has any flaws.

Originally Posted by Gardamorg

If it were possible to teleport a craft's fuel, than it wopuld be possible to travel at light speed.

Once teleported, the craft's fuel will will undergo a series of stages, the fuel starts out as raw hydrogen, a remote laser beam fuses and heats this hydrogen into plasma, this laser beam is very powerful, and fired from a solar powered space station, that is also a very large Bose Einstein Condensate Transmitter, to teleport the fuel to the depths of our galaxy, it needs to be BIG.

In a few minutes, the plasma generated from the heating hydrogen will be so hot that it will burn newly arrived hydrogen (from a BEC Receiver built into the craft) into plasma without the need of the high powered laser.

This will cause a chain reaction, the plasma will become so hot that it's atoms will release energy by themselves, and the hydrogen will become so hot that it will transmute into more plasma, which in turn will release more energy, making the whole craft self sustained.

The craft requires NO energy, the space station that fires the laser beam is what acts as an energy source, it converts the fuel into energy, and over time allows to fuel to convert itself into energy, and the fuel is teleported from the space station's BEC Transmitter.

The Craft can be as large as needed as well.

Once the Craft reaches light speed, it can coast to it's destination.

[CraigD]

Originally Posted by Gardamorg

My idea has been modified, see if it STILL has any flaws.

Yes, the idea of accelerating any sort of machine to the speed of light in vacuum in ordinary space is fatally flawed. These flaws have been explained so many times in so many books and websites that I won’t repeat them here.

Gardamorg, I recommend you try achieving about the same level of understanding of physics as the writers of Star Trek in the 1960s. These non-scientists knew you couldn’t accelerate to the speed of light, and that however you do it, spaceflight like they were depicting would require fantastic amounts of energy be stored in a small space, and without consulting blue ribbon panels of physicist and engineers (or even much talking among themselves), came up with a couple of not too unreasonable ideas:

• Since the highest possible energy density is found in antimatter (via annihilating it with matter), use antimatter fuel
• Since you can’t travel faster than the speed of light in normal space, don’t try, but rather change space (via “warp drive”)

Although actual physics (eg: the Alcubierre metric) suggest that many times more energy is required to do the sort of things depicted in Star Trek, we can at least give a nod to its science fiction writers’ guesswork as being roughly in the right direction.

In short, for spaceflight to be much different than it is now, we need to imagine spacecraft that are much different than they are now. Imagining larger, more massive ships with more powerful rocket motors doesn’t seem a productive line of thought.

While I’ve gone and brought science fiction into the discussion, I might as well trot out the time-worn idea that Star Wars is to blame for some “dumbing down” of the popular scifi audience. While both Star Trek and Star Wars are space opera – comedy and drama with scientific trappings, not science lessons with a supporting dramatic or comedic narrative – Star Trek, IMHO, better avoided the physically silly. The writer/producer system of 1960s TV that gave us Star Trek appears to have provided a better informal scientific peer-review process than the essentially single-handed (Steven Spielberg) writer/producer process that gave us Star Wars.

[Janus]

Originally Posted by CraigD

The writer/producer system of 1960s TV that gave us Star Trek appears to have provided a better informal scientific peer-review process than the essentially single-handed (Steven Spielberg) writer/producer process that gave us Star Wars.

A lot of this had to do with the fact that in developing the series, Roddenberry sought out the opinion of scientific advisers and made use of their advice when possible. For example, they spent a great deal of time and energy designing the bridge so that it not only looked good on film, but so that it was as practical a design as possible. Roddenberry felt that it would help the audience buy into the premise better. The studio attitude was more on the lines of "why are you wasting time with this? You've got some chairs and blinking lights, that's good enough."

[Gardamorg]

after all of this debating, I think the most likely candidate for a space craft will be the amalgam of many different things;

The first thing we need to do is overcome the earth's gravity, I'm talking about assembling and launching crafts from Earth Orbit. A way to do this is by building space elevators.

One problem with space elevators is that they need to be extremely strong in order to support their own weight. They can be made this strong by giving them super nano structures, using nanotubes such as these.

A problem with making such neatly built nano structures is that we can't do it. Which is where nano=assembly comes in.

If we can get a craft into space, and launch it in a vacuum, than we have overcame one obstacle, which does reserve a lot of fuel. But another obstacle is accelerating out of our solar system. A proven way to do this is with a magnetic sail. There are many advantages to a magnetic sail, one of which is it's ability to be completely self sustained by the sun until it leaves the solar system, this is because it's magfield can be expanded as it furthers the sun, thus accelerating at great speeds.

Now there is a problem with traveling the distance in between solar systems, which is vast, but this solar sail coasting is a very great advantage, after the craft can no longer use the mag sail method, it could switch to a self sustaining fusion method of propulsion.

This is perfect because so far the craft hasn't used up any fuel for fusion, so the fusion actually starts when the craft is no longer in the solar system!!! But there is one disadvantage to creating such a fusion reactor, it has to be HUGE!!!

But thanks to the space elevator, and the mag sail, it can be huge, to no risk! This self sustaining fusion craft, will be able to travel from one solar system to the other in just a few hundred years, because it will constantly accelerate as the fusion's energy release constantly perpetuates, and it is already moving fast from the mag sail's caost.

Now all that is just for GETTING there, now getting back is even harder.

[freeztar]

Space elevators are one of the coolest "maybe within reaches of possibility" sci-fi novelties to think about imho. Without delving into them too much here, I just wanted to point out Craig's excellent post on calculating mass for different materials that might possibly be used for cable in a space elevator system.

[Moontanman]

Originally Posted by freeztar

Space elevators are one of the coolest "maybe within reaches of possibility" sci-fi novelties to think about imho. Without delving into them too much here, I just wanted to point out Craig's excellent post on calculating mass for different materials that might possibly be used for cable in a space elevator system.

I like the idea of a space elevator as well but i wonder about it's flaws. Like it's fragility, an errant aircraft or even more likely a purposeful aircraft could knock it out easily and then all the man years of construction and mega tons of materials would be lost. I've also read that a trip up the elevator would take weeks or even months, I've looked but I can't find where I read that. A space elevator has huge potential but lots of bugs to work out.

[Gardamorg]

Space elevators would be great if achieved, no, they would be monumental.

This is because a self sustaining fusion reactor is THE greatest propulsion method, and a craft can be built large enough to fit a large fusion reactor on board if it doesn't have to escape earth.

It's perfect, the only flaw is that the metal will over heat and where out over time, which is why the fusion reactor would have to be turned off every once in a great while, and it's walls would have to be replaced, which won't be much of a problem.