Bussard Fusion Ramjets -- Solving the Drag Problem - General

[Thread music: [MEDIA]http://www.youtube.com/watch?v=svwqHhTQC5E[/MEDIA] Thanks mercurius for the link. In loving memory of Carl Sagan.] So you know, the biggest problem with interstellar travel is the amount of fuel is requires (The energy to send 100 tons of matter to Alpha Centauri in less than 50 years is 200 times what Earth uses in a year). But what if you could have infinite fuel? The Bussard Fusion Ramjet is a ship that picks up interstellar hydrogen with a magnetic field (Note: It must be first ionized by a UV laser mounted on the ramscoop). The fuel comes from space itself, so you can in theory accelerate [I]forever[/I]. Too good to be true? Sort of. The first problem using "raw" Hydrogen for fusion is different from fusing Tritium and Deuterium. DT fusion is achievable, proton-proton fusion is something that will probably take decades of research. The main problem, is, however, the drag problem: You can't fuse Hydrogen when the ship (Or the Hydrogen, depending on your point of view) is moving at .999c. You have to stop Hydrogen, then fuse it. This creates much much much more drag than thrust. How do we solve this? The first alternative is the RAIR Ramjet (Ram-Augmented Interstellar Rocket). You see, fuel and reaction mass are two different things (Except in a chemical rocket). Example: In a nuclear rocket, fuel is the nuclear reactor and reaction mass ("remass") is the Hydrogen or whatever you push through the exhaust. A RAIR Raimjet carries its own fuel (Often Deuterium/Tritium pellets), and picks up interstellar Hydrogen for reaction mass. So while it doesn't have infinite fuel, it does have infinite mass. Here's how a RAIR Ramjet would work: [IMG]http://www.daviddarling.info/images/Bussard_ramjet.jpg[/IMG] While it might not be as efficient as the actual Bussard Ramjet, it's pretty close. Here's the mandatory SketchUp explanation: Initial Configuration: [IMG]http://i44.tinypic.com/348redx.png[/IMG] A fusion drive accelerates the craft, fast enough to allow the ramscoop to operate: [IMG]http://i43.tinypic.com/14xnyte.png[/IMG] The fusion drive is ejected: [IMG]http://i43.tinypic.com/5yd98y.png[/IMG] The ship picks up interstellar Hydrogen. The Deuterium and Tritium in the tanks is fused, and the Hydrogen is used as reaction mass: [IMG]http://i40.tinypic.com/208jgpj.png[/IMG] The ship just coasts at high speeds: [IMG]http://i43.tinypic.com/8xpt2r.png[/IMG] The ship picks up interstellar Hydrogen, and stores it in the tanks (Creating drag, slowing down the ship a bit while its about to reach its target star): [IMG]http://i40.tinypic.com/rubq52.png[/IMG] The ship turns around, and fires antimatter and Hydrogen into the reaction chamber. The antimatter causes low-grade p-p fusion reactions that slow down the ship: [IMG]http://i43.tinypic.com/rqyc03.png[/IMG] A solar sail is extended, and is used to maneuver at low speeds inside the target system: [IMG]http://i44.tinypic.com/2r5u5oz.png[/IMG]

Meh snipes are mean and I'd rather not be banned. Didn't they recently unvail some engine for space shuttles that theoretically cuts travel time to like 1/4 of what it normally would be? Something like 39 days to get to Mars.

I think I've seen you make a thread like this before? I'm curious, What drives you to be so interested in it?

Hmm, interesting idea, but where do you reckon we'd get the antihydrogen to power the slow-down maneuver?

[QUOTE=Theo213;20835205]I think I've seen you make a thread like this before? I'm curious, What drives you to be so interested in it?[/QUOTE] I dunno, I've always been interested in space and interstellar flight.

You should paint flames on the sides of the spaceship. It will make it go faster.

[QUOTE=Arachnidus;20835210]Hmm, interesting idea, but where do you reckon we'd get the antihydrogen to power the slow-down maneuver?[/QUOTE] Soon, we'll be able to create self-replicating nanobots. You send them to the Moon, and they'll create solar panels to power huge particle accelerators to create antimatter. They're called Asimov Arrays, and they're basically the only way to produce antimatter on a very large scale (But to trigger the fusion you only need a few micrograms).

[QUOTE=Aman V;20835174]The problem of drag... drag. Drag Racers?! VROOOOOOOOOOOOOOOOOOM! [IMG]http://geekswithblogs.net/images/geekswithblogs_net/TakeNote/WindowsLiveWriter/NHRAGatorNationals2008DragRacingAndCre.0_9C8A/CrewChiefProCar_01_thumb.jpg[/IMG][/QUOTE] Failed attempt at being funny, bad reading.

[QUOTE=Roll_Program;20835258]Failed attempt at being funny, bad reading.[/QUOTE] shut up furry [highlight](User was banned for this post ("This reply is rude and adds nothing to the thread topic" - verynicelady))[/highlight]

Go build one, looks like the government won't be anytime soon so you could forget about nations having a proper space exploration program.

[QUOTE=NorthernFall;20835443]Go build one, looks like the government won't be anytime soon so you could forget about nations having a proper space exploration program.[/QUOTE] I wish...

[QUOTE=CzechOutMyBapes;20835391]shut up furry[/QUOTE] ahahahahah [highlight](User was banned for this post ("Why reply" - verynicelady))[/highlight]

I doubt this will happen within half a dozen centuries, but it seems feasible if we have the right technology. I also agree with Czech.

Isn't there a problem with the amount of hydrogen in our region of space though?

[QUOTE=Aman V;20835174]Meh snipes are mean and I'd rather not be banned. Didn't they recently unvail some engine for space shuttles that theoretically cuts travel time to like 1/4 of what it normally would be? Something like 39 days to get to Mars.[/QUOTE] Either a fusion drive or [URL=http://en.wikipedia.org/wiki/ICAN-II]ICAN[/URL].

Great Description of a RAIR ramjet. At less than 0.999 c, the drag would decrease, right? Geometrically or arithmetrically? I was interested in speed, distance and relative to the nearest stars. Check out this excel file... Drat, how do you upload a file?

Love this concept. Interstellar travel won't be possible until we have a cheap way to get things into orbit. My bets are on the space elevator, but it could work better if, rather than an elevator, it was a train. A train running along a massive cable to an orbital space station/city. From there it'd be easy to move objects into space and back, and build the ships there in orbit. Then you could build a massive scale ship like this and carry another cable to start a colony on that planet.

Jesus, blast from the past. I also learnt how to use Blender in the past year.

[QUOTE=NanoSquid;32656607]Love this concept. Interstellar travel won't be possible until we have a cheap way to get things into orbit. My bets are on the space elevator, but it could work better if, rather than an elevator, it was a train. A train running along a massive cable to an orbital space station/city. From there it'd be easy to move objects into space and back, and build the ships there in orbit. Then you could build a massive scale ship like this and carry another cable to start a colony on that planet.[/QUOTE] Cheaper ways to escape gravity well, yes - for this solar system exploration. For the stars: they only become practical when we get above 0.1c. Unless we outfit generation ships - lots of problems with those. But at 0.1c we can begin to make stellar trips. I like the elevator idea but who would fund it, especially if it's built near the equator... [editline]6th October 2011[/editline] [QUOTE=Eudoxia;32656624]Jesus, blast from the past. I also learnt how to use Blender in the past year.[/QUOTE] Is that Blender as in "a blender," or am I missing something? Your past words linger in virtual space - Time & space overlap in strange ways. I was searching Ramscoops the other night and you popped up. Good science and good pictures! I've been working on a timeline and relative time (ship vs. Terra) to the near stars on an excel spreadsheet. How can I post that .xls file here?

[QUOTE]Good science and good pictures! I've been working on a timeline and relative time (ship vs. Terra) to the near stars on an excel spreadsheet. How can I post that .xls file here?[/QUOTE] No, but you can take a picture. Or post a link to a Google Docs spreadsheet. Is it something like this? [IMG]http://www.orionsarm.com/im_store/cone.PNG[/IMG] Because I fucking love this chart. [QUOTE]Is that Blender as in "a blender," or am I missing something? [/QUOTE] [url]http://www.blender.org/[/url]

[QUOTE=Eudoxia;32657413]No, but you can take a picture. Or post a link to a Google Docs spreadsheet. Is it something like this? [IMG]http://www.orionsarm.com/im_store/cone.PNG[/IMG] Because I fucking love this chart. [editline]6th October 2011[/editline] That's fantastic! Thanks for sharing!! Where does the tranquility timeline come from? My chart has speed on the vertical axis and columns of relative velocity, time to Alpha Centauri...Tau Ceti etc ordered by distance, how many earth years a one way trip takes, and how many ship years these trips would take. Sorry I'm such a newbie, but how do you log off your account? I think I've looked everywhere but obviously not...?

[QUOTE=EmpireStar;32657722][QUOTE=Eudoxia;32657413]No, but you can take a picture. Or post a link to a Google Docs spreadsheet. Is it something like this? [IMG]http://www.orionsarm.com/im_store/cone.PNG[/IMG] Because I fucking love this chart. [editline]6th October 2011[/editline] That's fantastic! Thanks for sharing!! Where does the tranquility timeline come from? My chart has speed on the vertical axis and columns of relative velocity, time to Alpha Centauri...Tau Ceti etc ordered by distance, how many earth years a one way trip takes, and how many ship years these trips would take. Sorry I'm such a newbie, but how do you log off your account? I think I've looked everywhere but obviously not...?[/QUOTE] It's from Orion's Arm [url]http://www.orionsarm.com/[/url] The AT/BT timeline starts in 1969. You don't log off, you clear the cookies and that should do it.

[QUOTE=Eudoxia;20835152]The main problem, is, however, the drag problem: You can't fuse Hydrogen when the ship (Or the Hydrogen, depending on your point of view) is moving at .999c. You have to stop Hydrogen, then fuse it. This creates much much much more drag than thrust.[/QUOTE] I was under the impression that the main problem is that there's no way to actually build the collector. A physical collector would need to be hundreds of miles in diameter to supply enough hydrogen to sustain thrust (especially within the local bubble and our dearth of interstellar hydrogen), but would be damaged incredibly easily and so isn't practical. A magnetic collector is stymied by the fact that hydrogen is pretty much neutral for all such purposes, and would need to somehow be ionized first to be used. Until that issue is sorted, Bussard Ramjets are still firmly in the realm of science fiction.

You'd use lasers to ionize Hydrogen so the collector can catch it. And a lot of the Hydrogen in the interstellar medium is ionized.

Thanks Eudoxia. I'm going to try converting this .xls into a .png or jpeg or something ... But, [Since no questions are stupid, but some are revealing:] Do I clear the cookies through the browser or with the anti-virus at homebase?

Browser.

[QUOTE=Eudoxia;32659101]Browser.[/QUOTE] Thank you for your information, courtesy, and patience. So, with this ramscoop we are talking about four separate methods of propulsion. First, Deuterium and Tritium provide fusion power for initial thrust and then to ignite the interstellar hydrogen. That ionized hydrogen is the second method of propulsion covering the middle of the journey. At the top end, diminishing returns due to drag force the vehicle to coast at high velocity (I wonder what the threshold value is: where drag starts? How fast does it increase?). Then, homing in on the target star they use the hydrogen scoop to purposefully create drag while topping off the tank of stored hydrogen. The ship flips and then they burn the stored hydrogen with the third propulsion system, antimatter, to slow the ship down from interstellar speed. Finally they employ the fourth propulsion system, the solar sail, to maneuver toward the target planet(s) Conceptually, there's more that can go wrong with four systems than with three. So why not dump the antimatter (and all its containment equipment) and use Deuterium and Tritium fusion to burn the stored hydrogen in the deceleration phase? Conserve on mass, simplify the system, and avoid containing and handling very touchy anti-matter. What do you think?

[IMG]speedandTime001.jpg[/IMG]

You need to upload it to a website, such as [url]www.filesmelt.com[/url], and then get the link from there and put it in the IMG tags.

[QUOTE=Theo213;20835205]I think I've seen you make a thread like this before? I'm curious, What drives you to be so interested in it?[/QUOTE]It's space, does he really need an excuse?