Radiation engines?
- Thread starter KJbushway
- Start date
Well that's just physically impossible. Energy doesn't come from nowhere and all reactions, even nuclear, consume fuel of one sort or another. Matter and energy cannot be created or destroyed, it can only change form. What you're basically taling about is a perpetual motion engine which simply can't work without breaking the laws of thermodynamics and if you could do *that* then you wouldn't need to build an engine at all.
Actually not true. A solar sail meets his most recent definition. "Radiation that moves a ship with little or no fuel to create it."
Right. I spoke wrong. I should have said. I am looking not for an answer but maybe for something that doesn't use so much fuel as a rocket does but still does these things
Escape Earth's magnetic field
Provide good thrust and can be turned off and on(doesn't have to run 24/7)
An go faster than any modern rocket.
Can any type of radiation do this?
Is there projects on this already?
Is it even possible?
Does that clear that up. I am terrible at asking questions sometimes.
Thats true, Silvercrest has a point. But now it doesn't quite fit what I said above. But maybe its a one-two propulsion.
Escape Earth's magnetic field
Provide good thrust and can be turned off and on(doesn't have to run 24/7)
An go faster than any modern rocket.
Can any type of radiation do this?
Is there projects on this already?
Is it even possible?
Does that clear that up. I am terrible at asking questions sometimes.
Thats true, Silvercrest has a point. But now it doesn't quite fit what I said above. But maybe its a one-two propulsion.
Okay, now we're getting somewhere. I think you mean "escape Earth's gravitational field", not magnetic field, but I'll give you that one.
I think to be perfectly honest, the laser propulsion drive I mentioned yesterday is the only thing that would come close to your requirements. Like I said, it shoots a ground-based laser at the ship and ignites or burns off material carried aboard. The expelling of this material is what provides the actual propulsion. You still have to carry fuel material for the purpose, but you don't have to carry oxygen for on-board ignition like you do in a rocket. This would save considerable weight over a rocket.
And you're not carrying your energy source on board. This would save considerable weight over something like nuclear thermal propulsion (the aforementioned NERVA).
And obviously it meets your on/off requirement, unlike a solar sail.
I would expect this propulsion could reach escape velocity and go faster than a standard rocket. Just depends on how powerful the laser is.
The wiki article I posted talked about various laser drives, but I was unclear on how many of them have gone beyond the experimental stage.
I think to be perfectly honest, the laser propulsion drive I mentioned yesterday is the only thing that would come close to your requirements. Like I said, it shoots a ground-based laser at the ship and ignites or burns off material carried aboard. The expelling of this material is what provides the actual propulsion. You still have to carry fuel material for the purpose, but you don't have to carry oxygen for on-board ignition like you do in a rocket. This would save considerable weight over a rocket.
And you're not carrying your energy source on board. This would save considerable weight over something like nuclear thermal propulsion (the aforementioned NERVA).
And obviously it meets your on/off requirement, unlike a solar sail.
I would expect this propulsion could reach escape velocity and go faster than a standard rocket. Just depends on how powerful the laser is.
The wiki article I posted talked about various laser drives, but I was unclear on how many of them have gone beyond the experimental stage.
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Sure but as someone already pointed out; like with the laser driven sails that's an external force acting on the ship. It still needs a fuel source in the form of the hydrogen/helium fusion reaction a the sun's core. Granted that's not a fuel source that's liable to run out any time soon (depending on the star) but it's still a very limited form of travel. For one thing I gather the rate of acceleration and deceleration is supposedly very slow and as with wind sails, it's at the mercy of external forces and can't really generate it's own thrust.
Put it this way, I wouldn't want to be on one of those things if it passes into an eclipse and finds it needs to make a course correction, or (in the case of a laser driven sail) if there's a problem on the ground and the laser either looses power or looses the ship's lock-on. Good luck slowing down!
Actually I tend to agree with Reverend, other than that the point about the sun acting as "fuel" is being over-literal. The concept of "fuel" generally assumes that it's carried on-board. Plus, I wasn't talking about a laser sail per se, I was talking about an external laser which heats up on-board fuel so you generate your own thrust. Much better acceleration.
But the rest of it is true. You can't get energy for nothing, and there will always be practical limitations. In this case, if you're not carrying your energy source onboard, you will be dependent on one that's external (not to mention being dependent on the people running it.) And things can happen.
I said this is close as you can get to your radiation drive. I didn't say it was perfect.
But the rest of it is true. You can't get energy for nothing, and there will always be practical limitations. In this case, if you're not carrying your energy source onboard, you will be dependent on one that's external (not to mention being dependent on the people running it.) And things can happen.
I said this is close as you can get to your radiation drive. I didn't say it was perfect.
Lorna
Lieutenant Commander
Excellent, well I think Data is floating around somewhere in the Bassen Rift, better get La Forge on that because he'll probably need fixing up.
I got it. If I'd gotten here earlier, I'd have answered "virtually all of them."
Real answer to the content of the extraordinarily poorly worded question: fission-fragment drive. The bonus is that it's the best engine in the whole wide world, for Isp. Anytime I'm writing stuff about near-future space travel, FF is my go-to propulsion method. If it's Star Trek, it's that warp nonsense, but for harder science in the further future it would be a laser- or mirror-driven sail. Problem with those is slowing down.
If you don’t carry oxygen in some form, how in hell is the fuel supposed to burn?
Nothing says it has to burn. You just need to heat it until it transforms into gas or plasma. The laser does that. Then you expel it.
Of course, "fuel" may be the wrong word. The article uses "propellant". There are a lot of other highfalutin variations on this theme, few of which I claim to understand. Here, take a look. http://en.wikipedia.org/wiki/Laser_propulsion
Of course, "fuel" may be the wrong word. The article uses "propellant". There are a lot of other highfalutin variations on this theme, few of which I claim to understand. Here, take a look. http://en.wikipedia.org/wiki/Laser_propulsion
For in-system travel, slowing down isn't a huge problem. After all, you wouldn't actually be traveling in a straight line with one of these things----it isn't efficient. Instead, you would place yourself into an orbit around the sun. Angle your sail to increase your orbital velocity, you move farther away (head to Mars). Angle it the other way, you move closer (return to Earth).
The basic requirement is that you must propel masses in opposite directions to change the velocity of a spacecraft. The chemical reaction between fuel and oxidizer (both propellants) is just a means of heating the resulting combustion product. The resulting expansion/pressure ejects the gases from the nozzle. At lower masses but much higher velocity magnetic fields could eject a plasma that wouldn't require combustion.
A solid booster, like those used for the Space Transportation System (commonly referred to as "The Shuttle") combines fuel and oxidizer in the same layer of solid propellant in a sturdy steel casing. While that eliminates some complicated and potentially troublesome mechanisms like valves and pumps, a solid rocket will have to keep operating until all of the propellant is exhausted.
Each time a spacecraft uses a "slingshot" maneuver to change direction the planet it passes experiences a change of direction as well. Since the mass of the planet is so much larger than the spacecraft the planet's change of motion isn't really measurable.
I'm wondering if a spacecraft could use a mirrored probe sent ahead of it to decelerate. While such a procedure might increase the probe's lead ahead of the main spacecraft, it might be able to reflect a high power laser beam in a manner that could generate thrust for the main spacecraft back towards the original source of the beam.
A solid booster, like those used for the Space Transportation System (commonly referred to as "The Shuttle") combines fuel and oxidizer in the same layer of solid propellant in a sturdy steel casing. While that eliminates some complicated and potentially troublesome mechanisms like valves and pumps, a solid rocket will have to keep operating until all of the propellant is exhausted.
Each time a spacecraft uses a "slingshot" maneuver to change direction the planet it passes experiences a change of direction as well. Since the mass of the planet is so much larger than the spacecraft the planet's change of motion isn't really measurable.
I'm wondering if a spacecraft could use a mirrored probe sent ahead of it to decelerate. While such a procedure might increase the probe's lead ahead of the main spacecraft, it might be able to reflect a high power laser beam in a manner that could generate thrust for the main spacecraft back towards the original source of the beam.
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