Fusion Propulsion

Fusion is the power of the stars, and if we can master it, we will be able to send our spaceships to others stars.
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Credits:
Fusion Propulsion
Science & Futurism with Isaac Arthur
Episode 305, July 15, 2021
Written, Produced & Narrated by Isaac Arthur
Editors:
Andy Nelson
Anne Kopperud
A.T. Long
Darius Said
Cover Art:
Jakub Grygier www.artstation.com/jakub_grygier
Graphics:
Jeremy Jozwik www.artstation.com/zeuxis_of_...
Ken York / ydvisual
LegionTech Studios
Sam McNamara of Rapid Thrash
Sergio Botero www.artstation.com/sboterod?f...
Music:
Markus Junnikkala www.markusjunnikkala.com/
AJ Prasad • Dark Future - Staring ...

[@almcdonald8676]

I’ve gone to bed slightly drunk, to listen to this soldier-scientist spin lyrical stories of our future as the gods of our ancestors and suddenly, the world is alright again.

[@zurn56]

That's how I got hooked on his videos! My roommate in 2019 was playing his video to get to sleep after we hit the bars in Beaufort.

[@CreeperDude-cm1wv]

Imagine explaining fusion to an ancient Egyptian Time traveler: right so fusion is basically the sun in a small container. Egyptian: so you put a god in a can

[@nerobernardino88]

Time Traveler: Yup, you learn quickly!

[@twenty-fifth420]

Honestly if it works, it works. Not our fault the ancients mythologized and divinely attributed nature to the world. At least for polytheistic religions. I think the Time Traveler might even open with that like: “Okay so imagine if you had the power of a god in a can so we can move throughout space without having to mummify ourselves.” Random illiterate egyptian, probably smoking papyrus: “Dude woah. The future sounds so cool. Praise Ra!”

[@ranfan1820]

@@twenty-fifth420 Ra in a can. Every Egyptian has one! Praise the sun!

[@Zarcondeegrissom]

it's always amazing how some just assume that because someone is religious, that they lack basic understanding skills. this is the civilization that made some rather impressive things despite not having modern tools. ye may want to take a look at shadiversity "Medieval people were not flat earthers". watch?v=YiRWdOedrrI it's a halo earth! lol. ancient Egypt being well before the time of suppressing the peasants, ye may find the lack of words for some things more difficult than explaining the concept. it's fire, just a lot hotter. hell, may be usefully for that new iron forging they were starting to tinker with.

[@twenty-fifth420]

@@Zarcondeegrissom I already saw that video, I was joking. Also the Burning of Library of Alexandria set back scientific progress by at least 1,000 years. Trust me, I know. Also your first sentence does not many sense straight up. Also I am more sympathetic to polytheism so this joke was made in jesting support of an idea of a random Egyptian who meets a time traveler in a library and then gets told that 6,000 years later that you can bottle Ra in a can like a can of coca cola lol. I am sure it would be much appreciated with curiosity. Also, Praise the Sun! And Praise Ra!

[@dragoninthewest1]

2:14 I once heard someone say "Every car is a deadly weapon capable of mass destruction. Remember that when you're speeding down the road."

[@geemanbmw]

Car is as deadly as a loaded gun is the saying

[@dragoninthewest1]

@@helloworld9064 that sounds like something that come up in a video

[@wilfriedklaebe]

@@helloworld9064 just needs to go at 99% c...

[@jgr7487]

I love how "we can just make a ramjet with a black hole" is so nonchalantely said by Isaac Arthur. the power scales that are talked about in this channel are amazing!

[@Nethan2000]

You get used to it.

[@cryptolicious3738]

how fun does a lab leak of a black hole sound? i had a dream thats how earth ended. hopefully not...

[@rozzgrey801]

Isaac has a Matrioshka-level intellect which makes such mind-boggling feats a walk in the park.

[@jgr7487]

@@Nethan2000 I'm here since the beginning, & loving it

[@jgr7487]

@@cryptolicious3738 depending on its size, nothing will happen.

[@grantfomin6829]

Ah yes. The fusion torch drive that spits out a relativistic jet of radioactive iron. My favorite.

[@garthnareng4898]

Why radioactive that just means you've not used all of the energy for acceleration?

[@mopspear]

Sounds like MY WIFE!

[@muninrob]

@@garthnareng4898 Radioactive because you're binding neutrons to nuclei so you can use them (the neutrons) as additional reaction mass, and most of the time when you do that, the resulting isotope isn't stable. Same process as nuclear enrichment in a fission reactor, but instead of being surrounded by a neutron emitter (the reactor), you're in a constant flow of neutron radiation (the directed exhaust).

[@garthnareng4898]

@@muninrob I thought it was just an ideal hypothetical fusion reactor that takes in 56 protons and gives out an iron nucleus going out at whatever the mass difference in kinetic energy is.

[@Dragrath1]

​@@garthnareng4898 For some context there is an iron peak in the binding energy of atoms which results in a variety of product close to the peak one such supernovae byproduct is Fe 60 which has a half life of 2.6 million years Given the random nature of decay processes that isn't coming back add neutron bombardment to the equation and you get extra of the heavy isotopes

[@SporkmanBW]

"A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive." - The Kizinti Lesson (from Larry Niven's Known Space series)

[@TheVillainInGlasses]

Or, in other words, “Sir Isaac Newton is the deadliest son-of-a-bitch in space!”

[@TheReaverOfDarkness]

Once you fire this hunk of metal, it keeps going 'till it hits something! That can be a ship, or the planet behind that ship! It might go off into deep space and hit somebody else in ten thousand years! If you pull the trigger on this, you are ruining someone's day, somewhere and some time!

[@HeliosFive]

I know of that one. It's the first rule of warfare

[@drachefly]

Not QUITE accurate, as a small angle spread will ruin things far quicker for the weapon than for the drive.

[@LordFalconsword]

I remember humans had been brain washed into being woke wimps in that universe as well, all but incapable of violence. Seems apropos.

[@BigZebraCom]

I was going to build some fusion-propelled spacecraft--but then things got really crazy at work.

[@airborneranger-ret]

lol

[@BigZebraCom]

@@yorkyone2143 Thanks for the encouragement. But at work I've just been saddled with the Henderson Account--it's a nightmare, let me tell you!

[@nias2631]

I wanted to fuse some atoms but I couldn't get it together...

[@yulu803]

@@nias2631 XD

[@BigZebraCom]

@@nias2631 I know how you feel!

[@ramuk1933]

As your spaceship shoots a laser at the destination to slow down, the destination puts up a solar panel to get energy from it.

[@OpreanMircea]

Or a mirror to accelerate a second smaller outbound craft

[@isaacarthurSFIA]

:) Or fires defensive turrets at you. If you did have a beam-style drive I'd guess you'd be expected to keep it as 2+ beams off at different small angles, though having them track on a big power collector is a potentially good approach.

[@muninrob]

Destination uses a mirror to reflect it back to a mirror on your ship, that reflects it back to that same mirror at the destination. This way you get a larger slowing effect per photon emitted. (At that scale, that's a LOT of energy saved)

[@Dragrath1]

Or you could launch your laser near a target black hole at an angle precisely calculated to return that laser pulse to you the net energy varying based on the spin alignment of the black hole. Dr. Kipping's Halo Drive is a fun concept that uses light to perform the Penrose process while avoiding the whole pesky tidal disruption problems.

[@muninrob]

@@Dragrath1 Wouldn't you need to use something with mass, in order to keep the captured kinetic energy?

[@henrytjernlund]

"In order to travel between the stars, we will need the power of the stars." A great T-shirt graphic.

[@achtsekundenfurz7876]

"We wanted to get to another star, so we built our own star to take us there." Should be a popular shirt among . . . _starcrafters._

[@tranquilitybase8100]

Don't forget the first rule of warfare: all fusion drives can be used as a weapon.

[@JRexRegis]

All drives, really. - An orion device is just a cluster nuke - a fusion drive can be used as a kinetic WMD - an antimatter drive contains antimatter that can annihilate - A black hole drive contains a singularity that can be unleashed

[@ancapftw9113]

@@JRexRegis for that matter, a chemical engine can just move you fast enough to ram them really hard.

[@machematix]

go fast -> big crash

[@faust7756]

Faster the transport the more deadly the transport is generally. Unarmed Spaceship is a bad trope

[@rommdan2716]

@@ancapftw9113 Yeah, that's how misiles works

[@a-blivvy-yus]

With how bright and powerful starship drives need to be, I feel like stealth in space becomes a "needle in a haystack" kind of stealth once you get enough ships travelling around, instead of being actually "I want to go unseen" because you're always going to be seen, and the trick is not to be noticed among the clutter of other people being seen...

[@cw8jwh]

Coat the hulls with VantaBlack.

[@a-blivvy-yus]

@@cw8jwh Which as a dark colour, is a significant heat radiator and will give off significant amounts of infrared radiation which will make it highly visible to common sensors used in space. It also doesn't absorb radio waves, so wouldn't mitigate radar detection.

[@cw8jwh]

@@a-blivvy-yus I know. I was being sarcastic.

[@a-blivvy-yus]

@@cw8jwh xD sorry, I missed that at first...

[@Chad_Thundercock]

"At temperatures of millions of degrees" ...and now that song is stuck in my head.

[@isaacarthurSFIA]

Yo ho it's hot, the sun is not a place where we could live But here on earth there'd be no life without the light it gives

[@Chad_Thundercock]

@@isaacarthurSFIA I've said it before, but I'll say it again because it's worth repeating - I really appreciate you, sir.

[@portalopener7759]

@@isaacarthurSFIA : Fusion energy break through is now successful: kzbin.info/www/bejne/faTdZIefptd7ZsU

[@kerbodynamicx472]

It's scary to imagine how much destructive power was packed in these fusion torch drives we see in sci-fi, behind that bone-crushing acceleration is the heat to incinerate a planet, such is the power of stars!

[@Zarcondeegrissom]

especially when it's fusion candles for pushing gas giants out of orbit or into an orbit, it's a lot of energy.

[@The_Bird_Bird_Harder]

@@Zarcondeegrissom One thing I love is that in Starsector (game) an item you can get to aid a player colony is a fusion powered... Heat lamp.

[@richmigala2539]

Fusion is a reaction in which two or more atomic nuclei come close enough together to form one ore more different atomic nuclei or sub atomic particles. The reaction may reach a stable equilibrium in which it separates from Massachusetts and creates its own thriving lobster industry. This is called the Maine sequence.

[@nias2631]

Nice!

[@NullHand]

Unless too many sub atomic particles are forced into too small a volume, in which case it must collapse into a MassHole.

[@portalopener7759]

@Rich Migala: Fusion energy break through is now successful: kzbin.info/www/bejne/faTdZIefptd7ZsU

[@mikedrop4421]

The fact they stacked the floors in the correct orientation is why I fell in love with The Expanse

[@fredwupkensoppel8949]

Video idea: Internet between colonies. How will we handle someone uploading KZbin videos on earth that people on Mars want to see? Surely Mars will have an independent planetary information network, but how and to what degree will we keep Earth-internet and Mars-internet snychronized? Will we do that at all? I'd be curious to see what you have to say about this topic :D

[@user-yq6ov6ow7l]

Almost surely be completely synchronized with just a few minute delay. Yeah it would be annoying to wait. We all survived with 14.4 modems. I mean multiplayer video games don’t usually pair you with someone on the other side of the planet either. The internet is sort of already segregated. KZbin.mars Now internet at another star system…that’s a better question

[@TastyBaldEagle]

You'd probably just try to copy the entire internet and synchronize them every hour

[@fredwupkensoppel8949]

@@user-yq6ov6ow7l Indeed. In that case, I wonder if we will have unmanned ships which are basically giant warehouses of harddrives with rockets that travel back and forth, or if we just won't bother.

[@virutech32]

@@fredwupkensoppel8949 it wouldn't make any sense to use ships. you would just send the data over tight beam. faster & doesn't require wasting tons of fuel

[@fredwupkensoppel8949]

@@virutech32 Question is whether or not intersolar tight beam is viable for high density data transfers, even considering possible future methods of compression. In computer networking, one of the first things you learn is "never underestimate the transfer rate of a van loaded up with harddrives zipping over the highway".

[@singletona082]

It is still mind blowing we have fusion reactors now. They just don't produce more power than you put in at least as of right now.

[@geekswithfeet9137]

A point often missed is that we technically don’t have to break even, as you get the input energy back anyway as heat. If you have heat engines running at 60% efficiency like some of the leading rankin cycles at the moment, then you only need another 40% to win out on top.

[@thorin1045]

@@geekswithfeet9137 Not exactly, if you get out 40%, than you only have 60% energy remaining, so your heat engine will generate 60% of 60%, 36%, and you still missed 24% to break even. Even worse, you do not need break even, at that point you use an insanely complex machine to do nothing. You need economic return level for actual usage, which is much higher, not sure how high, since we do not know the actual cost of the fusion reactor and the actual cost of the fusion fuel. The true big issue is that we currently not reached even energy positive state reliably, and very far from useful energy positive state, and than we could maybe start talking about economicly positive reactors.

[@ozzymandius666]

@@thorin1045 Maybe by 2150.

[@cedriceric9730]

They are " electric " neutron sources and expensive helium generators

[@jgr7487]

Helium factories are indeed quite fine.

[@Jondiceful]

The ram jet as a means of slowing down is actually pretty awesome. First the interstellar dust and gasses slow you down as you collect them. Then they slow you down again as you burn them as fuel. I imagine you scoop could be modified to serve as a pusherplate for accelerating too. Even a magnetic pusherplate as an extension on a physical one could help add efficiency to a standard fusion drive or might even be useful for ground-based laser or maser driven propulsion.

[@schmetterling4477]

Yes, we can buy unobtainium pusher plates cheaply at the X-Men hardware store.

[@martinmorrissey5647]

this guys accent and voice inflections give him an ET like authority

[@chrisgriffith1573]

The power from fusion drives means you can limit the amount of power you need for the task of acceleration needed. Once you achieve the desired balance of power, then you can make scaled uses of such technology, and all different levels of use can be achieved, shuttles to enormous vessels.

[@TheRogueRockhound]

Arthursday = Best day

[@Arrynek01]

You have no idea how happy this particular upload made me. I've spent the last fourteen days researching exactly this topic.

[@captainhakob814]

He makes the videos months in advance and some how in thinking of the topic when it comes out, the timing is crazy. I feel like he programmed me to feel like I'm the one making these choices

[@Arrynek01]

@@captainhakob814 So... What you are saing is that he's the Architect.

[@baylorgimp]

I like the way the web comic Schlocks Mercenary did kinetic weapons and high speed drives

[@matthewlong9821]

That was a great comic!

[@voxelsofsorrow]

like the c-sabots that the Partnership Collective uses to attack Tagon's Toughs early on! I miss that comic but I finally discovered the Culture series so it's like having a bunch of sequels in book form.

[@lanorothwolf2184]

I can sense deep emotions in intonation when pronouncing Uranus

[@secrom1014]

I just woke up early and needed your voice to fall back asleep! 🙏

[@iLikeMyOwnPosts]

🤣

[@miamijules2149]

You are not alone…. for a guy with a ‘speech impediment’…. he sure as shit has a great voice. Lolol

[@secrom1014]

@@miamijules2149 Him and John Godier are my go to's.

[@rayceeya8659]

Hey I recognize that web page 12min in. Atomic Rockets. I love flipping through that site and reading about all the crazy ideas that are out there.

[@dougnorthcote3420]

Excellent series of books that address some but by no means all, of using an Orion drive for moving some quite large stuff. Like stupidly large, multi trillion ton asteriods etc. Called "Live Free or Die" by John Ringo, loosely based around the "Sclock Mercenary universe about 1000 years before that timeline kicks off." or as Howard Taylor said it. "Best fan fiction ever!"

[@wildman8060]

Feels awsome to finally watch a vid right after release. Love your stuff man, its amazing for helping me worldbuild.

[@EddyA1337]

If we could ever have fusion propulsion like they do in the expanse... Acceleration that is so fast and efficient ships can be designed to use that as a means of gravity and flip and decelerate halfway

[@km5405]

the hard radiation the drives they use in the expanse would give off is something they kinda gloss over lol. even less efficient ones would be a game changer though, using fractions of a ship for fuel reserves not like 95% of the ship being fuel

[@EddyA1337]

@@km5405 for sure. While it is hard sci fi, it's still sci fi haha, and one of the best damn stories, books and show, ever told. My favorite thing is how Mars has a culture all its own. So glad James S.A. Corey are involved with the book to show adaption. But ya there would have to be a radiation shield or something in the reactor to protect the crew.

[@barahng]

@@EddyA1337 The Expanse lost me when they added in magical FTL portals. I'll stick to Alistair Reynolds.

[@skipperg4436]

@@barahng traversable wormholes can exist according to math models, but there is no mechanism proposed thus far how such things can form. There are so many things about the universe that we don't know that their existence can't be ruled out.

[@smoore6461]

I really enjoy going back and watching older SFIA videos! There are so many great videos to watch more than once! I would LOVE for the Unity story to come back again some day!

[@user-qf6yt3id3w]

I like the way in The Expanse the Epstein Drive seems like something which is a relatively minor tweak on existing fusion drives which makes them vastly more efficient.

[@larrybeckham6652]

But it is still Clarketech. I do not mind Clarketech with aliens who are a billion years ahead of us but I prefer humans to still within the known laws of physics.

[@Chad_Thundercock]

The biggest problem with the Epstein Drive is that someone always sabotages it, then blames the engine itself.

[@user-qf6yt3id3w]

@@larrybeckham6652 I'm not sure it is. It's just a very efficient fusion drive. Nothing in it breaks known physics.

[@larrybeckham6652]

@@user-qf6yt3id3w so, you checked the math on the Epstein Drive? IT IS A FANTASY!

[@larrybeckham6652]

@Roberto Vidal Garcia sorry. Your money is cheerfully refunded.

[@larrybeckham6652]

One my favorite episodes! I wonder if you could have a ship generate beams of positions that the leverage a jet of proton fusing with protons. And if the direction of the protons would make the excess neutrons join in the thrust?

[@larrybeckham6652]

This is in! The National Ignition Facility has used it's 192 laser array to fuse hydrogen-deuterium at Q of .7! Woohoo!

[@Inglonias]

This helped me understand how to play modded KSP a little better. Thanks!

[@yoshikhurazi1769]

Now I want a video on interstellar ramjet concepts, I always found the bussard ramjet idea appealing but was disheartened to hear it relegated to only being a braking solution. Glad to see that there are options out there.

[@businessbusiness9407]

There's a great sense of swagger to this one

[@alexanderp7521]

Acceleration/deceleration problem could be solved by using stasis chambers where crew will be frozen until the state of solid matter and then after acceleration/deceleration unfrozen (or remain frozen for duration of an entire flight). Or using transhumans (whose bodies consist of non-organinc matter entirely) as crew members

[@MrPants1100]

This is one of my favorite topics! Thank you for an amazing episode!

[@jon-laurencedecespedes2811]

i think the torch drives of the Hyperion cantos ,although later than Heinlein, are more akin to your examples. awesome vid as always .

[@rockscousteau]

Love all the videos. Seems like i am getting more notifications & you seem to do be doing more uploads than usual..............THAT IS AWESOME. Keep em' coming Isaac. These videos are DAMN GOOD

[@herbiehusker1889]

Happy ArThursday!

[@JustABill02]

What would be a reasonable maximum relative speed to use atmospheric breaking? Not necessarily to land, but to slow down. For example fly thru/thru the upper part of a gas giant on your way in to drop speed so you can land on an inner, more hospitable planet.

[@TheEyez187]

I was just imagining a Shkadov thruster powered not by a "normal" stars, but by a Neutron star (engine capable of 43,000RPM lol :D) or a Magnetar, using it's high magnetic forces to work as a tow truck to pull a fleet of vessels! :D

[@yimingwang8037]

put a shit ton of magnetar and create a stellar railgun :D

[@TheEyez187]

@@yimingwang8037 Adapt it so the railgun fires ships; Mass Effect-esque. -Or use the railgun to propel solar sails- you wouldn't be able to slow the fucker down at the other end. "It's entering orbit.... it's exiting the orbit.... and it's gone!!" >XD

[@versinussyrin577]

There are so many fusion drive concepts, some are viable, some not But riding something what is essentially a mini star on its own burning at millions of kelvins would be kinda badass

[@zenkomenhi]

This video helped me realize that ships in my worldbuilding project travel at 1% light speed

[@AugustusBohn0]

lovely opening CG clip 👌

[@PaulA-zp7hn]

Will watch this tonight. Thanks in advance for another awesome episode! (because it always is...)

[@evensgrey]

If your ship and cargo are tolerant of high accelerations, you don't have to just brake with a Bussard collector against the relatively thin, randomly moving interstellar medium. You can cut the end of the journey short by running down close to a target star and braking against the denser, highly direction stellar wind. This also should make it easier to kindle a fusion flame as stellar wind should be quite hot to begin with. (You do have to make a judgement call about just how suitable any given star is for this maneuver. Fortunately, any ship contemplating this maneuver is going to be watching that candidate star for several years, with increasing resolution, prior to having to make the decision as to exactly how to conduct braking.)

[@stevemickler452]

Dr. Robert Forward showed that fusion propulsion is not necessary in principle, for interstellar travel but you don't have to depend on light pressure as his concept did, since the beam can be focused to heat a propellant or converted into electricity for a magnetic reconnection or other electric rocket propulsion system. Beam powered rocket propulsion beats even antimatter rockets.

[@Babalas]

Fusion - so powerful it makes the earth spin backwards

[@makeracistsafraidagain]

Excellent topic!

[@Ockersvin]

Question for Isaac: how have you managed to gather this massive amount of knowledge on science and futurism?

[@mrcoryman1]

I'm pretty sure he's an accredited theoretical physicist, so I'd say a decade of higher education and the ability to understand and explain in rather simple terms highly complex concepts and ideas.

[@032Qrayber]

Damn, you are on fire these days

[@tomastomasi975]

Getting to the furthest planet in the solar system in 15/16days? So fast it sounds like fiction tbh.

[@JohannVF]

LLNLab just had a major breakthrough in ICF ignition.

[@skepticmoderate5790]

I just wanted to mention that in my thermodynamics class, the Bussard ramjet was used in the final exam, so future engineers really are thinking about these kinds of things.

[@Dani004able]

Why not use a magnetic bottle for fusion. This just needs to be bigger and stronger than our current ones. You could let some of the super heated plasma out at the neck of that bottle wich then go thou a magnetic field than make them move very straight out of your engine. There it is, propulsion directly from a fusion plasma, powerfull and with high exhaust velocity.

[@sunnyinvladivostok]

After being on youtube for years, I just barely stumbled on this channel from the sidebar recommendations.. Love it! Seems a step up in terms of actual content from other similar channels. Any recommendations on great episodes to start with?

[@Mtha77]

Surely it’s not a coincidence that you released this video yesterday, the next day the National Ignition facility announces a breakthrough or step forward in Fusion tech?? Did you know Isaac?

[@YodaWhat]

There is a HUGE differene between "laboratory breakeven" and *real world breakeven* that requires the output energy to be fed back in to drive the process, with 90% left over for external uses. What the NIF announcement is, basically, is CLICKBAIT.

[@richdarlowgolf]

I really hope we can do it Isaac, another fantastic episode thank you!

[@rommdan2716]

The best part of fusion propulsion is you have artificial gravity for free.

[@TheArtofFugue]

Would say that’s the best. Maybe the coolest though.

[@ANKITKUMAR-cl1og]

What has fusion has anything to do with gravity? Plz explain

[@rommdan2716]

@@ANKITKUMAR-cl1og Fusion propulsion would allow you to constantly accelerate a 1G for extended periods of time

[@yaomingas5425]

I like your videos, keep going

[@kenhelmers2603]

Thanks!

[@lloydfromfar]

That intro.. a few shattering words! :)

[@cryoine7194]

i always loved these intros

[@theOrionsarms]

But if you send the fuel for deceleration with another slower ship with tens of years before the passenger ship to be launched, and when second ship reach near the slowest one decelerate only enough to match the speed of the ship that carries fuels from the rest of deceleration. That would need a lot of long term planning I think.

[@AvyScottandFlower]

A bussard ram jet might be about the only solution, for a spaceship NOT to disintegrate at such speeds..

[@TheEvilmooseofdoom]

There are a few issues with Bussard Ramjets too..

[@barahng]

@@TheEvilmooseofdoom Mainly that they don't work.

[@yumazster]

@@barahng They work as brakes well enough. Good for deceleration and filling up the tanks as far as I can remember. The miscalculation in the initial design had something to do with the interstellar medium density assumptions. We know more now and that is why we know you couldn't accelerate with the ramjet.

[@ericgolightly8450]

You might need a good particle shield otherwise.

[@kalebmaciver7117]

Awesome vid

[@Lukegear]

Ha! It rhymes!

[@kb9oak749]

It's sad that the chances of Humanity leaving for interstellar space are decreasing dramatically as our imminent societal collapse proceeds apace.

[@Khannea]

Isaac, can you have the following ... (1) You colonize a KBO object in a specific direction, somewhere 5-10 billion kilometers from the sun, construct a large industrial complex there... (2) construct a space elevator on that KBO that exports large structures (3) construct a linear accelerator radiating outward from that KBO capable of accelerating high mass physical objects to an appreciable fraction of the speed of light (4) ...launching fuel, food, industrial components, etc. (5) you accelerate a large vessel rom the asteroid belt in the direction of the KBO (and beyond which lies a star you can colonize) (6) you overtake aforementioned KBO, find a KBO that's about 5-10 billion kilometers further, and construct a large industrial complex that, we label this complex 00002 (7) repeat steps 2, 3, 4 on complex 00002 (8) launch a second vessel from the asteroid belt, find a third KBO somewhere 10-20 billion kilometer from the sun, construct complex 00003 (9) keep on repeating earlier steps in ever greater increments for "a few hundred to a few thousand times" creating a daisy chain of industrial facilities (10) ... thereby creating a sequence of refueling structures capable of injecting acceleration and eventually deccelleration energy into an interstellar vessel (11) ... let's say one such colonial entity created every year, a constant sequence of vessels underway to build the next chain in the sequence (12) .... let's say ten light years, so let's assume a thousand relay stations might be needed per light year (13) ... thereby allowing a huge interstellar structure ship to maintain indefinite fairly substantial (1G?) accleration and decceleration for the voyage... (14) ... thereby allowing such a "constantly refueled ship" to travel (15) we can of course launch these chainbuilding vessels much more often. They don't need to accelerate at 1G initially. But as more stations emerge in the sequence, we can increase their speed and (over time as technological advances percolate down the chain) their capacity to upgrade on the fly, or build ever more sophisticated waystation structures (16) My guess is we don't need a full ten thousand years to build all waystations, if we launch substantially more often, and as the chainbuilders gradually get more fuel from stations being erected "in their path", laying the sequence might be done substantially faster, say, under a thousand years. (17) and eventual travel times for a fully operational chain might come down to decades for constantly refuelled vessels. And with sufficient capacity you can send a LOT of colonial ships to the respective destinations. Downside is you need a chain for every single star system you want to colonize, give or take. Advantage is this technology works in both directions. I label this project a "Khannea Daisey Chain".

[@pieceofschmidtgamer]

First Rule of Isaac Arthur's Fight Club: All Fusion Drives can be used as weapons. Second Rule of Isaac Arthur's Fight Club: Talk about Isaac Arthur's Fight Club because it's interesting.

[@chrisgriffith1573]

Thats a great insight: "To get to the stars, we will need the power OF the stars!"

[@onetruekeeper]

Plasma drives are often depicted as some sort of long duration rocket propulsion that uses fuel very slowly.. But plasma drives can operate without expelling fuel out the back end. Once a plasma is formed it needs to be contained in a vacuum magnetic bottle. The more energetic the state the plasma is kept in the greater the pressure exerted against the magnetic bottle. If this pressure was unevenly distributed the plasma drive will tend to move in the direction with the greater amount of pressure just as a conventional rocket engine would but in this case there will be no exhaust expelled into space.

[@Windows035]

"we've had fusion power since the mid 20th century" *wolfenstein music plays*

[@allenyordy6700]

Happy Isaac day

[@johnrickard8512]

It has just occured to me that to deal with the neutron radiation from fusion we should use depleted uranium shielding. You see, when depleted uranium absorbs neutrons it becomes plutonium which I don't think needs introduction. Needless to say this is a superb way to capture the energy lost in the form of rogue neutrons.

[@myriaddsystems]

Fascinating listening to this presenter's accent alone

[@ezramantini8078]

Love it

[@barryon8706]

My short-term favorite torch drive is the nuclear salt water rocket. But if a starship were built using it, I think I'd like that built in orbit around some other planet. I don't consider myself nuclear-phobic, but that's a lot of fuel, all of it a nuclear hypergolic monopropellant. For long-term, matter to energy conversion. Somehow. Little black holes, inducing proton decay, whatever.

[@DerekJones1081962]

The difference between a fission bomb and a long lived power reactor is that a significant number of neutrons are born delayed. I have long theorized that a hybrid fission-fusion device could be built that the fusion fuel flowing through a fission core and controlled/catalyzed by the free neutrons reflected back into the fission core. Hence, adding a feedback/control system for the fusion fuel prior to compression and ignition in the separate fusor. I just can't get anyone to pay attention long enough to understand the underlying phisics.

[@gabiausten8774]

Greetings from Germany. 🇩🇪 Thank you for the fantastic new Video. ✅✅✅❤️

[@yomiyama]

At 24:39 - you say that you're calculating flight time with constant acceleration *and turnover* for a given distance and you give the following formula: t=√(8d/a) You said "and turnover", yet, you didn't take into account mission apogee, that would have implied halving the distance that is in the square root and multiplying the result out of the square root by 2 giving us a multiplier of 4 in the square root not 8. The actual formula is: t=√(4d/a) I would go into details but it's almost 4 a.m here.

[@ronaldwhite1730]

thank - you .

[@morrowj74]

Never forget the Kzinti lesson!

[@Beamer1969]

A laser to accelerate and a ramjet braking system?

[@acarrillo8277]

This couldn't have been timed better considering the recent success in California with an ignition of a fusion reaction.

[@Zarcondeegrissom]

oh, nice, congrats to California (rrr, correction, LLNL). in fairness, fusion has been done for some time, they are just putting in more energy than there getting out of it so far, mostly because it's all small experimental reactors not meant for sustained reaction (just 100 trillionths of a second).

[@NullHand]

Yeah, but I wouldn’t call the NIF exactly small. A 10 story football stadium full of lasers all aimed down on a 2mm target. I think they are claiming a fusion energy yield of 70% of laser energy in. Not specified is the electrical efficiency of the lasers. I don't think this design was ever seriously about fusion for power generation though. More a way to do experimental fusion physics for weapons once the Nuclear Test Ban treaty removed the thermonuclear Easy Button. Still a good milestone. Science makes both swords and plowshares possible. Shame its so much harder to fund the plowshares.

[@shadowhenge7118]

I think this really highlights that we need to manipulate forces like inertia, gravity, and even mass if we want sci-fi's version of space travel. Inertial dampeners, anti-gravity, and warp fields are the real plot armor of sci-fi. If theres a chance any of them are possible, we should pursue them a little more than casually alongside fusion drives and such.

[@DavidEvans_dle]

When they make fusion power motorcycles. I'll let them off the hook on the delay of developing flying cars. :)

[@SACR3DBAC0N]

Been waiting for this for a while! I haven't finished watching this video, but is there a chance we could get your take on dV budgeting and interplanetary/interstellar brachistochrone transfers?

[@barclinxox]

They just had a major breakthrough in fusion technology a few days ago in california.

[@mcconkeyb]

Woo-Hoo, Fusion power! Now we're talking, I'm fully on board for this! The pulsed fusion propulsion seems a bit barbaric, but it might work until we get more refined fusion drives. :-) Recent news from the National Ignitions Facility at Lawrence Livermore National Labs, claims that their inertial confinement experiment has achieved ignition for the first time, an achievement that has been many decades in the making, now instead of a million things that we need to get right, we only have 999,999 things to work out. :-)

[@TheEvilmooseofdoom]

That must be really recent news because their website only says they've made a significant step towards ignition.

[@mcconkeyb]

@@TheEvilmooseofdoom www.llnl.gov/news/national-ignition-facility-experiment-puts-researchers-threshold-fusion-ignition

[@5amH45lam]

We've (seemingly) yet to realise an affordable, safe, fusion-based form of energy production and storage (nor any viable alternatives, for that matter) because the petrochemical industry gets a severe case of _colonic twitchytitis_ when potential alt-energy candidates surface. For which they remedy by acquiring intellectual property from alt-energy inventors, at whatever amount both party's agree to. Those 'blueprints' are then locked away, never to see the light of day again. This behaviour is documented, continues to this day, and is the single biggest hurdle to the successful development of alternative energy sources.

[@portalopener7759]

@Mr Jean Deaux: Fusion energy break through is now successful: kzbin.info/www/bejne/faTdZIefptd7ZsU

[@pinoyhssf]

yes. a new video

[@Jumpyexponent45]

I am simple man. I see Isaac Arthur, I click like.

[@kartafla]

Smartest guy on KZbin.

[@klausgartenstiel4586]

man, the iron drive 🎸 that's just pure metal.

[@torjones1701]

2:57 Your Earth is spinning the wrong way. You're getting sunrise in the West rather than the East as is traditional.

[@BraveDave]

Haha. "As is tradition". It's also lit up on the side not facing the Sun and closer to the Sun than Mercury. A person stood on that Earth would see the Sun taking up about 50% of the entire sky. They'd also be incinerated :P

[@torjones1701]

@@BraveDave As was mentioned on reddit, there's a whole lot more wrong than that, but that's a good one too. Artists... what can I say? :)

[@BraveDave]

@@torjones1701 Yeah, I'm concerned with how dark the Sun is; like it's being eclipsed. Maybe that's why the Earth hasn't been burnt up! Also you can see distant stars to the side of it. I'm pretty sure that if I stared at the Sun right now I wouldn't be able to see the space behind it, and that's without it even taking up 50% of the sky! But I'll go and check anyway. Just off to go stare at the Sun BRB

[@peterhall8572]

Whenever I hear you talk about black hole powered ships I automatically think of the film "Event Horizon" that'll put you off the idea and give you nightmares

[@scottmoore6131]

Request update now that we have a fusion power plant that produced more power that went into it. The reason is this power plant looks like it’s almost built for space travel.

[@dbell1016]

Hi Isaac. I've had an idea for a rocket engine based on a variation of the VASIMIR ion drive. If nitrogen were used as the reaction mass in the engine, then after being accelerated by the grid the nitrogen ions were neutralized and allowed to recombine into diatomic nitrogen wouldn't that chemical reaction add enough energy to the plasma to bring it close to Epstine Drive levels of efficiency? I'm assuming a fusion reactor driving the VASIMIR. I know it takes a LOT of energy to disassociate a diatomic nitrogen molecule into two nitrogen atoms but going from 2N to N^2 is the basis of many hi-explosives. At least, this could allow practical single stage to orbit. It would be more efficient than a pure chemical engine and more powerful than an ion thruster. I'd love to hear any knowledgeable opinions out there. This idea has been knocking around inside my head for awhile now.

[@HalNordmann]

Don't know if it would be so good, but it seems like an interesting idea!