Do all space engines need fuel?

[Shinova]

Do all space drives need chemical fuel of some kind, or can some run directly off of power provided by the reactor?


Secondly, is there a plausible power source (reactor) in sci-fi that can run for a virtually infinite amount of time?


And note, this is not for real-life but for sci-fi, but try to keep it plausible.

[NecronLord]

How advanced is the Sci-fi in question?

[Stormin]

Do all space drives need chemical fuel of some kind, or can some run directly off of power provided by the reactor?

some sort of gravity drive would not need fuel.

Secondly, is there a plausible power source (reactor) in sci-fi that can run for a virtually infinite amount of time?

Bussard Ramjet

[Shinova]

How advanced is the Sci-fi in question?

Howbout Star Trek, Star Wars, Stargate SG-1, and Babylon 5 levels.

[Enlightenment]

Do all space drives need chemical fuel of some kind, or can some run directly off of power provided by the reactor?

The stuff that gets put into a reactor to make power is fuel.

The stuff that gets blasted out of the back of the ship to make the ship go fowards is reaction mass.

I think what you're really asking is if there are drives out there that require no reaction mass. As far as SF is concerned, the answer is yes. Take a look at http://www.grc.nasa.gov/WWW/PAO/html/warp/ideachev.htm for the terminology and characteristics of various potential reactionless drives.

[Graeme Dice]

Do all space drives need chemical fuel of some kind, or can some run directly off of power provided by the reactor?

An EM drive where you use EM fields to pull/push yourself along wouldn't need reaction mass, but you might need a monopole magnet.

Secondly, is there a plausible power source (reactor) in sci-fi that can run for a virtually infinite amount of time?

This depends entirely on how much energy you need. M/AM will power a 60 W bulb for 40 million years off a kilogram of reactants. A small black hole will radiate for a long time that depends on how much mass you feed it. Zero-point fields are another good sci-fi source of limitless energy.

And note, this is not for real-life but for sci-fi, but try to keep it plausible.

[Shinova]

This depends entirely on how much energy you need. M/AM will power a 60 W bulb for 40 million years off a kilogram of reactants. A small black hole will radiate for a long time that depends on how much mass you feed it. Zero-point fields are another good sci-fi source of limitless energy.

Energy enough to power a Star Wars/Star Trek/ B5/SG1 style spacecraft or warship.

[Shinova]

And wasn't zero-point energy considered a myth?

[NecronLord]

Excluding such deus ex mechanica as hyperspace then only SG-1 has demonstrated a space drive tech, as the goa'uld ships are stated to use an inertialess drive.

Theortically if you have repulsor tech you can pust against something. But it is a little useless once you are away from a stellar mass.

[Shinova]

Would somehow compressing a star down to walnut size give a fairly large amount of energy available for use by a spacecraft?

Just a crazy idea I though up of.

[Graeme Dice]

This depends entirely on how much energy you need. M/AM will power a 60 W bulb for 40 million years off a kilogram of reactants. A small black hole will radiate for a long time that depends on how much mass you feed it. Zero-point fields are another good sci-fi source of limitless energy.

Energy enough to power a Star Wars/Star Trek/ B5/SG1 style spacecraft or warship.

In Sci-Fi, yes, in real life, no. But then, you wanted Sci-Fi energy sources.

[NecronLord]

IIRC ZPE is not actually a myth. There are just a pile of myths surrounding it. A very big pile. A huge massive pile.

To utilise ZPE in a meaningful requires Clarketech.

[NecronLord]

How about this?

http://www.orionsarm.com/ships/amat-efficient.html

[Enlightenment]

Would somehow compressing a star down to walnut size give a fairly large amount of energy available for use by a spacecraft?

Crush a star to the size of a walnut and you'll have a black hole. While black holes can be used for power sources it'd be more efficient to simply leave the star where it is, capture its power output to create antimatter, and use antimatter to power the ship.

There's reason to carry around a stellar mass when there are other ways of carrying around large quantities of energy.

[Warspite]

Well, you could jump on the ZPE bandwagon, like everyone one else is doing, personally, I consider it a brain bug, nevertheless... That thing provides limitless energy, much like B5 Hyperspace Tap.

Singularity propulsion is a good way also, the only problem is in creating the black hole in the first place, and controling it in a way so the starship doesn't get eaten by it.

The Orion's Arm site uses advanced AI and exotic matter, to produce advanced propulsion, usually in the form of femto- and pico-tech (bellow nano-tech) in conjuction with negative or ultra-mega-dense matter.

Sail power is limited only inside a star system, and the power generation capacity follows a inverse square law.

Then there's the good old stargate system... That can allow for a more interesting Universe, since it's required for the gates to be in place, before any ship can use the system, making space exploration a slow and methodical task (I'm using those in my Sci-Fi Universe), or when a system fails, what happens to the starships in-transit? It opens a door to a lot of possibilities.

For conventional power generation: ion drive, fusion drive, and anti-matter drive, all require reaction mass. Anti-matter is the more dangerous in my view, it has this annoying habit of going with a bang, and a cloud of gamma radiation.


In the end, I think it's best if you give your readers the trusty "magic vroom-vroom technology" (TM), while at the same time invent some power source for yourself to satisfy your ego. Just don't explain the thing, look at what happened to ST... (and SW is going the same way, I'm affraid...)

[SWPIGWANG]

GIANT ANTIMATTER FLASH LIGHT OF DOOM DRIVE

yes, light has non-zero momentum appearently....

[kheegster]

There's this concept where you fire a big-ass laser at a ship with a giant sail...the radiation pressure will accelerate the ship, sorta like the solar sail concept on steroids.

KG

[SyntaxVorlon]

That idea does have merit, but it requires a GREAT deal of radiant energy to provide that push, the reason being that not only do you have a big, multigigawatt for speedy intersystem travel, laser handy and a reactor to power it you've also got most of that energy being reflected of to keep the mirror sail from melting. Really good intersystem travel would only be possible with some form of hibernative sleep, city-class ships for multigenerational star travel, or real space bypass(hyperspace, wormhole, what have you)
Right now, if the US or UN put $100 billion dollars into creating space based construtors using meteor/asteroid mining, or simply using an asteroid, to build a city in space, with Ion drives and enough spin to create half gravity(assuming a large asteroid or station) there could be a colony in another starsystem in one or two centuries, given build time and travel time.
In Sci-Fi anythings possible, sometimes probable to reality. But do space drives need fuel.
YES!
In the end all the fuel we use is given energy by the sun, a great fusion reactor in the sky. Fuel is a part of every drive system, except the most fanciful, because there has to be energy expended. If you wanted to be REALLY fanciful you would go with the Culture, which assumes hyperspace contains an infinite amount of energy(though if the cyclic universe and certain other theories are correct this could be accounted for), and that it was useable not just as an energy fount, but as a thing to push against.

[Howedar]

And watch the hell out where you point that drive...

[Wicked Pilot]

This may suprise you so hold on to your ass..


Yes there are means of locomotion that propels spaceships without using fuel! In fact, it exist in real life, and has been used since the 1970s!

Now I know what you're say, something like "Wicked Pilot is full of shit, but then again, he usually is right, and handsome at that." Let me explain, and this is somewhat obvious, the concept of gravational assist. Yep that's right, the method that sent the Pioneers, the Voyagers, and Galileo into the outer solar system. The starships literally steal energy away from the planets they get their assist from. Think of what happens if you grabb onto a spinning merry-go-round, and then letting go. You basically get shot off, just like a spacecraft getting shot out of the orbit of a planet. Large bodies like Jupiter can shoot a spaceprobe across the solar system. Of course, a planet like Jupiter will lose so much energy in the proces that after thousands and thousands of years, it will have traveled one centemeter less around its orbit.

Maybe not what you're looking for, but this actually exist. As Bill Nye would say, "Science rules... and so does Wicked Pilot."

[kojikun]

Well, to go out into the wastes of science faction, you might consider Negative Matter drives. The theory behind them is something alone the lines of "it pulls towards matter but matter is repeled by it, so they eternally are locked moving away from the negative matter". Its like trying to make a toy car move with two magnets and both are attached to the car. Only not. LOL

The math works too. and you really arent doing much of anything. All you do is stick the negative matter behind you and you move away from it. And it always stays behind you (just dont touch it). Some kind of containment would be necessary.

The reason it works is because it has negative momentum and negative energy. So by speeding it up, it looses energy (much like a tachyon). This is very convenient, because the overall energy of the system (the ship and the negative matter) remains the same because as your ship gains energy, the negative matter looses energy. Energy is conserved. I'm also guessing that this goes for mass too, as you go to relativistic speeds, your mass increases, but so does the negative matters negative mass. So you gain and it looses.

I BELIEVE this means the craft would have FTL potential but im not sure. In my universe it does, so NYAH

[Enlightenment]

I BELIEVE this means the craft would have FTL potential but im not sure. In my universe it does, so NYAH

Negmatter drives are just another way of gaining momentum. They can't and don't work around relativity. FTL requires a different type of magic.

[Wicked Pilot]

The math works too.

No it doesn't. Try U=Q-W

[Einhander Sn0m4n]

Well, to go out into the wastes of science faction, you might consider Negative Matter drives. The theory behind them is something alone the lines of "it pulls towards matter but matter is repeled by it, so they eternally are locked moving away from the negative matter". Its like trying to make a toy car move with two magnets and both are attached to the car. Only not. LOL

The math works too. and you really arent doing much of anything. All you do is stick the negative matter behind you and you move away from it. And it always stays behind you (just dont touch it). Some kind of containment would be necessary.

The reason it works is because it has negative momentum and negative energy. So by speeding it up, it looses energy (much like a tachyon). This is very convenient, because the overall energy of the system (the ship and the negative matter) remains the same because as your ship gains energy, the negative matter looses energy. Energy is conserved. I'm also guessing that this goes for mass too, as you go to relativistic speeds, your mass increases, but so does the negative matters negative mass. So you gain and it looses.

I BELIEVE this means the craft would have FTL potential but im not sure. In my universe it does, so NYAH

Okay, but I think you might have some difficulty stopping unless you have at least two engines. If one gets destroyed, the ship'll fly out of control until the other one gets ejected. Then it'll fly off, steadily (and probly quite rapidly) gaining speed until it hits something. Auto Destruct charges may solve this problem, but it'll make for highly volatile targets for enemy ships to aim at to prematurely "activate" the system. All this on an already dangerous propulsion system. If there was a way to turn off the effect, it may be viable. Good concept, but the only use I would see for it would be self-propelled projectiles from a weapon of some sort.

[Enlightenment]

The math works too.

No it doesn't. Try U=Q-W

You might want to look up Robert Forward's paper on negmatter drives before dismissing them quite so quickly.