WWYR: Thrusters

"Wheelerguy" (wheelerguy) 08/14/2015 at 03:47 • Filed to: WWYR, Which Would You Rather?, Thrusters, Space

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I’m going to space, but regular ol’ rockets wouldn’t cut it past the Moon. What else we got? These two.

Plasma thruster?

Or ion thruster?

Or maybe another kind of thruster that’s entirely different and more powerful and efficient than either two?

Pick.

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Mike > Wheelerguy 08/14/2015 at 04:04

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Once we get nuclear fusion down, I predict that nuclear thermal rockets will rule all non-atmospheric flight. Basically, you take a very light fuel, such as liquid hydrogen, and run it through a heat-exchanger connected to a nuclear reactor. The gas rapidly expands, producing the highest exhaust velocities possible with anything resembling a conventional rocket. Since specific impulse is directly related to exhaust velocity, you end up with a rocket with a rather low thrust/mass ratio (unsuitable for any launch stage), but a level of efficiency an order of magnitude greater than anything we can dream of with chemical rockets.

You could also design a nuclear-powered jet based on the same concept, using atmospheric air instead of stored fuel, allowing for an essentially indefinite range. Convair actually tried to do this with a B-36, but the fission reactors of the day made this both unfeasible and unsafe. Very cool bit of largely forgotten technology, nuclear thermal propulsion.

Wheelerguy > Mike 08/14/2015 at 04:12

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Added to the choices as “Fusion-reactor thermonuclear thruster”. Man science sure rocks—until it blows up in your face. If it’s fusion-based, though, it’s fine and dandy.

Anyway, pretty off-topic, but the comic book character Hazmat should visit Tony Stark some time. Then after some more time, request for a unique reactor heart and suit that can let her live without emitting radiation (reactor heart) and also amplify her powers (suit), and take lessons in hand-to-hand combat, like kickboxing.

Axial > Wheelerguy 08/14/2015 at 05:17

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Those are all sissy answers.

What you want is a Nuclear Salt-Water Rocket .

If you are really into rocketry and how to generate “hard” science-fiction (like yours truly here), I recommend you peruse all of Atomic Rockets and not just the part I linked. It is very, very informative, with a healthy dose of humor to keep it entertaining of the concepts themselves don’t already get you excited.

Snuze: Needs another Swede > Wheelerguy 08/14/2015 at 08:39

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Nuclear bomb blast coke can dispenser rocket!

This is Project Orion. It was a very early concept (1950’s) to try and figure out, using tech of the day, how to get man out of our solar system.

The concept they came up with was to build a payload module mounted to an enormous blast shield mounted via massive shock absorbers. They would then periodically detonate small nuclear bombs behind the craft and it would accelerate riding the shockwave of the blast.

The reason I mention Coke cans is that the project designers needed a way to carry and dispense the small bombs so they actually consulted with engineers from the Coca-cola company. They figured Coke had a lot of experience developing controlled mechanical dispensers, so perhaps they could leverage that knowledge and scale it up to make a bomb dispenser.

And now you’ll never look at a Coke machine the same way again.

You can tell a Finn but you can't tell him much > Wheelerguy 08/14/2015 at 09:15

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If you want to travel out of the solar system, this is your best bet for adding velocity.

Gravity slingshot for that added velocity you’re looking for.

Wheelerguy > Axial 08/15/2015 at 10:31

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Thank you! Looks helluva more powerful than the ones I put up. Particularly the fusion one.

Q: I’ve been meaning to build a big (as big as the second LEGO spaceship shown or thereabouts) space mobile refueling center or supertanker or something. Any suggestion on storage and containment for the fuel of said rockets?

Axial > Wheelerguy 08/15/2015 at 13:20

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Clusters of aluminum pipes with some form of internal neutron dampening toward the rear of the ship ought to be fine. You want it toward the rear so that the crew can be traveling away from any potential contamination. Putting all of that fuel mass behind also allows for a more fuel- and materials-efficient ship design if you move the engines up front, creating a “puller” type system rather than a “pusher.” A pusher-type ship has to be able to not buckle or crush itself under acceleration, mandating sturdier and more massive construction. More mass needs more fuel to move, ergo less fuel-efficient. A puller-type, on the other hand, just has to not shear away, which is an easier application of force to manage.

Wheelerguy > Axial 08/16/2015 at 03:02

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I learned something new today. And surprising, it’s based off “Page One, Chapter One, of the Petro-Sexual Handbook” (Clarkson, J., hell if I know when he said it). Thanks.

Now to turn your words into a model. Any basic kind of shape you can suggest so I can make the tanks stackable?

Axial > Wheelerguy 08/16/2015 at 16:36

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The ship is going to essentially be a central pylon with the fuel tanks stacked both concentrically and end-to-end at the back, engines near the front, and crew quarters even ahead of that, with some sort of internal or external method of moving from module to module. If your ship is going to be capable of relativistic speeds (as a fuel tanker, probably not), then you are going to need a domed shield at the front whose diameter is equal to the widest point on the ship.

You’ll also probably have radiators up front to get rid of any heat imparted to the ship by the engines.

Wheelerguy > You can tell a Finn but you can't tell him much 10/25/2015 at 11:44

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I’ve known about slinging craft past Jupiter, but I gotta wonder if I can do what hammer throw athletes do to get max velocity out of a gravity assist, then time it with a drive boost for max propulsion.

You can tell a Finn but you can't tell him much > Wheelerguy 10/25/2015 at 12:59

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I don’t think that will increase your speed at all. You would have to carry that fuel to Jupiter which means you would be moving slower when you get there since you didn’t burn it to accelerate. Your acceleration would be higher with the gravity boost / fuel burn combo, but since you come in at a lower speed your final speed should be identical.