The Nuclear Option

[@isaacarthurSFIA]

Note: Don't bother leaving a post about how I pronounce nuclear, or rather mispronounce it, at least not if you want a polite reply :)

[@alexgoldsmith8598]

Those wascally wabbits should have put on closed captions

[@palarious]

I don't have a speech impediment and people still make fun of me for how I say nuclear.

[@isaacarthurSFIA]

I'm sure they're the same folk who like to wisely inform people that iceland is green and greenland icy, and that soccer is called football in Europe. :)

[@alexgoldsmith8598]

Isaac Arthur So basically annoying people, it's pretty silly to correct someone with a speech impediment for their pronunciation

[@alexgoldsmith8598]

Isaac Arthur I've never had problems understanding you though

[@underbay]

Isaac, I haven't posted a comment on KZbin in well over two years. However, I wanted to take this time to thank you for creating these unadulterated videos that allow us to voyage into esoteric scientific concepts. You are truly a master of your craft; the visuals and scientific thought behind each episode are remarkable and deserve praise. I wish you the best of luck in your future endeavors, you are certainly a talented individual. Thank you for sharing the knowledge, my friend.

[@robt4976]

I second what C D said. Fantastic content. Keep it up

[@Hazellycom]

Grazie Isaac!

[@theCodyReeder]

Listened to this on my phone while driving earlier re watching for the video now. :)

[@ConstantThrowing]

It's Cody! Fancy seeing you here, man. Hope all is well with your channel after the recent KZbin nonsense.

[@SpaceCakeism]

I'd love to see, (... /hear) a Cody & Isaac collaboration! Though, they somewhat cover different topics, they're likely to have overlapping ideas. (I mean; Cody, has already kinda confirmed this, with his comment.) Besides, from watching a chunk, of both their contents; I know that both of them, have a lot, of interesting things, to talk about, on several topics. Therefore, I don't really think, that finding a suitable topic would be the hardest; rather, I'd think it'd be the format, and/or style of the video; taking into account, that the format/style, of their content, is very different, at least from my point of view. Then again, the difference in the formats, might actually be used, as a benefit; e.g. by having a video, that focuses on the theories, and one, that focuses, on the experiments. (Though, I guess this would only work; if Isaac agrees, on not picking, an over-the-top topic, like megastructures, lol.) P.S.: I have a lot, that I'd like to say, concerning format differences; although, I think it's for the best, that I let it slide, as I don't want to say too much, and unintentionally, insult neither, by pointing out such differences. as I enjoy both's content, quite a lot.

[@SpydersByte]

@@SpaceCakeism holy shit buddy, you really need to learn how to use commas. That was a painful read.

[@ATLTraveler]

@@SpaceCakeism Your knowledge of semi-colons and commas is equal to my dog's knowledge of rocket science. Don't use a semi-colon if you don't know how to properly use it. I would say the same with commas, but it's virtually impossible to type without commas. Perhaps just use less of them I guess. I really hope English isn't your first language or I am embarrassed for you.

[@ATLTraveler]

@@SpydersByte bahaha I just commented something similar. What in the fuck is wrong with that guy...

[@firewolfquasar4230]

Happines levels: When you clean your room: 50 Before you open youtube: 100 After you open youtube normaly: 110 When you open youtube and see that PBS Space Time, Kurzgesagt and Isaax Arthur have uploded: 1000

[@biggamer500]

9000+

[@mikea2363]

Firewolf Is an astral conjunction.

[@enigma647]

i imagined big smoke "ooh" getting louder on each level

[@Kbwtor19]

Firewolf You might even say that these events increased the half life of your happiness. :D

[@DreamskyDance]

..when you roll one before new isac arthur and pbs spacetime. ( btw, pbs eons is quite good for paleontological and geological topics ;) )

[@theinte11igent1]

I find myself constantly having to replay things you say because the descriptions get so in-depth, and my brain constantly gets carried away with one idea while you are already on to the next one.

[@SpydersByte]

@daarkside uh, you mean the closed captions that he has gone so far as to add a graphic telling you to turn them on?

[@pigboiii]

I have watched so much isaac arthur that I am suprised everytime he mentions his speech impediment because I dont even hear it anymore.

[@prestomatic1989]

Pigman Rocker same. Sometimes i notice but most of the time I'm just captivated by what he's saying.

[@stardolphin2]

Some people could understand Stephen Hawking...*this* is nothing.

[@StrategicGamesEtc]

Yeah, I actually only notice it when he mentions it, and then it annoys me for a few minutes before I forget it and go back to enjoying the video. :D

[@databanks]

Talk to people from enough different countries and with enough various disabilities and you just stop noticing. Takes a closed or small mind to think less of a person just because they speak with a different accent.

[@oakwhelie]

I actually like his voice

[@freedo333]

I dont hear a speech impediment. Instead, I hear a smart fellow explaining some fascinating science

[@stevenhetzel6483]

This is like when people say "I dont see color." Like, we know what you mean, but its such a weird thing to say lmao

[@dougm3037]

Isaac,, I agree with you re the nuclear option. It's a power source that needs to be treated with kid gloves safety wise but there's no need to demonise the technology just because certain people have an irrational fear of anything nuclear. I believe that atomic rockets will have a significant part to play in space mining operations which I predict will be a significant contributor to the global economy. Thanks again for your efforts in putting this video together.

[@GodActio]

Think about how much research could be done on nuclear propulsion on the moon, exploding rockets is NOT an issue on the moon

[@dougm3037]

@@GodActio Totally agree. So much valuable research could be conducted on the moon.

[@tylersoto7465]

That's why the moon is a natural port, ship building and mining operations to start from, it has abundance of helium 3, uranium and thorium to power earth and moons electricity and spaceships too, it's low gravity would make things easier and faster to manufacturer and build and easily away too, it has large deposits of titanium and aluminum great building and ship building material and aluminum helps against radiation and is a conductor too ,there's gold and silver on the moon great as advanced conductor and radiation protection, silicates and diamond resources too for building and semiconductor material , diamond is 30x stronger as a semiconductor than regular silicone and a few other resources, so the moon is a natural hotspot for space and technology development

[@robertweidner2480]

No guts, no glory! Nuclear all the way! We should bring back Project Orion!

[@svampebob007]

it's a shame that the race to the moon was yet just another military propaganda. it shows that if we do go all in we can manage incredible projects with relatively simple innovations. I say fuck national security and let's head to Andromeda!

[@caav56]

*WHAM* *WHAM* *WHAM* quiet. I love "Footfall". I hope we won't need alien invasion to resurrect nuclear space propulsion projects.

[@duster0066]

Rodger that Rob! We could do Mars easy with a few guts.

[@justin2370]

Oh you will be happy in 2022

[@dickyboi4956]

@@justin2370 what's happening in 2022

[@dlt074]

is it just me, or are these videos getting better by the week? Isaac is really hitting his stride.

[@kokofan50]

No, the videos have definitely been getting better.

[@isaacarthurSFIA]

I try to raise the bar a little each episode, I'm glad to hear they haven't plateaued out yet. :)

[@zak7181]

It's been slow & steady improvement, so I don't notice it until I go back to watch early ones.

[@yASTROZIV]

How do you make video material?

[@deanjohnston5196]

your speech is fine, it actually sounds like a cool accent

[@ultimateanthony1883]

People will pay to speak the way he does if you know wat most accents sound like around the world.

[@altareggo]

lol agree!! Very clear enunciation, GREAT pronunciation, splendid timing and pacing, very nice emphases in all the right places... who could ask for more???

[@neruil77]

@marios gianopoulos sounds little like Cajun accent, like people from Louisiana..

[@user-dx2lf3is7b]

Damn that accent sounds so dumb

[@nathanb3134]

Sounds like the dude from Big Bang Theory! Barry Kripke!

[@rexxbare9255]

I see your message at the start of your video.... And I wanted to say... I dont think it's an impediment my brother. It is just your unique sound. I find it actually helps hold me to focus on your words surprisingly, and therefore it becomes easier for me to understand your concepts, not harder. Thank you for the time you put into this and all your videos. You are an amazing human.

[@cassgraham7058]

Easily the best, hollistic explanation of nuclear propulsion I've ever seen. I've been waiting for months for this, and it was well worth the wait! So far watched it three times. Once again, Isaac knocks it out of the park! (as of Saturday morning, already more than 30K views!)

[@kokofan50]

As someone with an interest in both nuclear reactors and space, I'm a little ashamed I didn't know about most of these. However, it was great learning about these rockets.

[@AliothAncalagon]

Happy Arthursday everyone!

[@IgnemFeram01]

Alioth Ancalagon And May the 4th be with you!

[@BaddAtom]

every time i get a spare half hour im watching Isaac Authur, this guy blows my mind

[@Rezwolf]

As a guy who just found your content, I'm happy you found your crowd and you have improved immensely.

[@cct2557]

If I didn't know better, I'd say you have a perfect creole accent. Great video!!

[@fragomatik]

Another great episode Isaac...and thanks for the shoutout mate!

[@isaacarthurSFIA]

Thanks for the loan of the excellent graphics!

[@Spagghetii]

Thanks for your hard work !!!

[@fragomatik]

Hey Spagghetii, thanks for your support, man!

[@JKTProductionzIncNCo]

gr8 work m8

[@Stuphologist]

f r a g o m a t i k

[@sirdouglashowel5thseat776]

Thank you sir!! love this channel, my best find on youtube so far.

[@mpetersen6]

One example of the GCNR powered vehicle is the proposed Liberty Ship Nuclear Rocket. Can be found on the Atomic Rockets site. Payload eight times of a Saturn V in a SSTO re-usable vehicle. Also for deep space work what about an arcjet powered by a nuclear/electric power source. The problem isn't the fissile mass as Issac states. Its the required subsystems to turn power into thrust. Excellent segment as always

[@francoislacombe9071]

I do believe that Project Orion, in its original design, was supposed to launch from Earth's surface. That was at the time when exploding nuclear devices in the atmosphere wasn't considered a big issue.

[@isaacarthurSFIA]

I think I've heard that too, but I can't verify, all the designs I've seen assume launch from LEO or further.

[@andrasbiro3007]

Yes, it was supposed to launch from Earth. Since the hardest part of space travel is getting out of Earth's gravity well, and Project Orion can do it effortlessly, there's a very strong incentive to at least consider the possibility. It was estimated that a launch would need around 1000 bombs, regardless of the size and mass of the vehicle. At least if you want living passengers in orbit. If you only have cargo that tolerates high acceleration, one bomb can be enough. During the nuclear weapon test series Operation Plumbbob, there was a shot (Pascal-B) which launched a 2000lb steel plate into the air with at least 6x escape velocity. Around the same time the best chemical rockets were barely able to put a 200lb satellite into low orbit. Since nuclear bombs are so powerful, an Orion spaceship doesn't have to be built from tinfoil like chemical rockets, and doesn't have to launch from the equator. They planned to build it like a battleship, and launch it from the North Pole during a snow storm to minimize fallout and other negative effects. In the original design the upper limit of the ship mass was 8 million tons, and since the specific impulse is ridiculously high, a significant part of that can be payload. More modern thermonuclear charges can reduce fallout to negligible levels, the Soviet Union tested 15kt bombs with 98% fusion yield (fallout comes only from fission) in the 1970s. 100% clean bombs are possible with using a microgram of antimatter instead of a fission primary.

[@grimjowjaggerjak]

Project Orion has been canceled because of the Treaty on the Non Proliferation of Nuclear Weapons if i rembember

[@cassgraham7058]

It was. The atmospheric pressure, especially lower in the boost phase, made it incredibly attractive at low altitudes, though. It's buried in the papers, but... Winchell Chung put together an incredible amount of information on this. www.projectrho.com/public_html/rocket/enginelist.php#id--Pulse--Orion

[@petersmythe6462]

Yeah. Although my impression is that "from Earth" in this context means from a nuclear test site as far away from human population centers as possible, not from cape Canaveral.

[@slayerofthebad9265]

You are proving time an time again to be a great addition to my science and space youtubers collection. Not only are your videos great in explaining everything about the subject you're talking about, but your voice is also quite nice to listen too, and after a few videos, the speech impediment isn't too big of a deal anymore. Keep up the great work, because you're really good at what you do! ^-^)b

[@r0bbiec0pus]

Excellent video mate. I'm slowly making my way through your list from oldest to newest and hope to catch up to your current videos by the end of the year haha Your material is the best there is on KZbin and it's only getting better and better.

[@bryantgaines6849]

Im a little late to the party but your work is amazing. Its so well thought out and in depth. I love the fact that these things are being thought of as well as spread in the world. While it is being consumed by far more people than i thought was interested in these subjects. Thank you Issac.

[@blind1337nedm]

Best youtube community ever. youre talking about something on a facebook group and not even a week later there's a related video! you're awesome man! -Spaghetti Jordan

[@johannespedersen2072]

First time commenting, i love you videos and i watch them all. You're one of the only youtubers where im legitimately excited once i see a new upload. Keep up the good work!

[@isaacarthurSFIA]

Thank you Johannes, I appreciate that!

[@Chlorate299]

5:13 I never considered that as a definition of specific impulse! That makes so much sense.

[@erikandersson1647]

Hehe, I liked the Elmer Fudd cartoon he added. I'd rather listen to a smart guy with a speech impediment, than another idiot using one of those speech synth programs.

[@Semicon07]

or another flat earther.....

[@diggydude5229]

Exactly. I automatically downvote videos with robotic text-to-speech narration. They literally don't bother to remove miscellaneous content like photo captions from the page before they turn the robot loose on it. I seriously doubt they even review their videos before uploading to hear how stupid they sound. It's just plain lazy. Putting forth zero effort doesn't deserve to be monetized.

[@edwardtupper6374]

RacerTV! lovely bikes, awful narrator

[@Hysteresis11]

100%

[@NuclearBumpkin]

Ooh, that fission sail idea is actually pretty good if you make it a semisphere. And water is a great neutron reflector that doesn't appreciably decay due to exposure.

[@damonawesome]

Keep it up Isaac, this is my favorite channel on KZbin by far! And that's saying something when you think about the time I spend on here haha

[@jjjthe_dark7260]

I just wanted to congratulate you on using your own voice. I know many people who would be embarrassed to put their voice online even without a speech impediment and I am encouraged by the pride you have of your voice, despite, I assume, criticism. I also learnt a lot so keep making those videos please!

[@rayvnstevens]

has anyone else mentioned an interest in thorium? love your channel, keep up the good work.

[@nobody4248]

Oversimplification: you can do with it basicly same thinks as with uranium reactor. (Maybe even better).

[@danaphanous]

thorium by itself isn't generally fissioned from my understanding after researching the subject because it is very stable. It just can easily be used in a breeder reactor to create stuff that can like U-233 (which is very nasty). The upside is that U-233, even though it is horribly radioactive produces relatively stable products that don't take thousands of years to become safe. The main reason we don't do this is the tech isn't developed like uranium tech and they don't want to put in the money. And as you have probably heard it wasn't developed because U-235 and plutonium tech was better for making bombs from the byproducts. At this point we know it would probably work but the research to get it all developed is projected to be billions of dollars so no one wants to make the switch from what we have. I assume it is the same fear that he mentioned here in some ways: the fission reactors we have work and already cost us billions to develop, so people want to stick with them till something much better then fission comes along (such as fusion). They will probably regret that choice if fusion isn't figured out in this century though.

[@krabkit]

i am still amazed that you don't have more subscribers because every episode is so well done and obviously takes a lot of work and love. there are plenty of channels that put out less than 10 min of half fast content a week and have far higher numbers. you have been growing a lot though, i remember when you still had less than 10k subs

[@AKlover]

Hey Isaaac how bout Thorium molten salts reactors as a topic???

[@kokofan50]

Power sources of the future would be good.

[@AKlover]

If memory serves this Thorium salt thing was tested and proven, something to do with the USAF nuclear (engine) bomber program. It would seem it cannot or is no good at making weapons as the reactor type is the reverse of what we use for fission energy and weapons production.

[@kokofan50]

A molten salt reactor was designed and flown as on of the two options for a nuclear powered bomber in he 50s, but it was a uranium fueled design. It wasn't until the late 60s with the MSRE at Oakridge lab was thorium used in a MSR. Although, the Shippingport reactor, the first pressurized water reactor, had experimented with breeding thorium before the MSRE. As for the making weapons grade material, thorium breeders do produce isotopes that can be used to make weapons but it's exceedingly hard to remove and work with that isotope. U-233 is a hard game emitter with a short half-life.

[@SpathaMagna]

+AKlover yep, it's a rather safe reactor design too, since it doesn't use water for cooling so it can't experience a hydrogen explosion of the sort that happened at Fukushima. The real benefit to having molten salt reactors (aside from safer fission power) is that it creates a demand for Thorium, which means you can open a rare earth element mine, and not have to worry about where you're going to store all the Thorium you collect as you search for lanthanides.

[@Fiercesoulking]

I personally have the idea of an Thorium-Plasma drive it would be a lot more safer , or at least the safest how you can get with a nuclear option ^^

[@RustyDust101]

Darn, now I tried to restrain myself to merely two of your videos a day for multiple weeks. Just so I could drag out the pleasure of anticipating and watching them... ...and now I binge watched five in one day, and it includes this one as the currently latest one... waaaaahh, why can't it be Thursday already?!? ;-) You, sir, are really doing an awesome job at this. Keep it up.

[@fraggenaught]

Been a Fragomatik subscriber for years. Love his stuff. Thanks for giving him a shout out. No, my username has nothing to do with him. Been using it for years before I ever heard of Fragomatik. Just a neat coincidence. :)

[@fragomatik]

haha...move along, nothing to see here... ;)

[@w33leeg23]

Isaac, I don't often get the time (or more accurately have the patience) to watch videos that are any more than 5 mins long, but you're videos are always amazing and I always end up hooked and watching them entirely. Keep up the fantastic work!

[@w33leeg23]

Also, was the spacecraft at 26:01 the Nautilus-X? Always wondered why NASA never decided to use that concept, because it seemed like a very well thought out one.

[@matthewakian2]

I really enjoyed this. We're really lucky to live in an age were information can be shared so easily.

[@joshmnky]

I remember watching Fragomatik from a long way back. Looks like he's improved quite a bit! Also, I just finished watching all of your videos after discovering your channel about a month ago. It has been and will continue to be a pleasure!

[@isaacarthurSFIA]

Wow, I'm always a bit surprised anyone can binge watch these episodes, especially the older ones.

[@carminesassano6300]

@@isaacarthurSFIA You sir have brought much pleasure to this old insomniatic man, your subject matter is varied and detail oriented, please don't stop. Thank You Thank You Thank You

[@carminesassano6300]

@@isaacarthurSFIA You sir have brought much pleasure to this old insomniatic man, your subject matter is varied and detail oriented, please don't stop. Thank You Thank You Thank You

[@nicholasandrzejkiewicz]

I don't understand the irrational amount of fear others have towards this.

[@TalkingAboutYooh]

Well, if there's an accident people tend to object to glowing in the dark.

[@robertweidner2480]

No guts, no glory!

[@pyrphoros8739]

nuclear power simply does have a bad connotation, like gmo's (no they will not alter your genetic material overwise your "natural"-food would do it was well!) But given that all the accidents derive from idiots misshandeling nuclear power ... we are in no short supply of idiots ... not even of idiots with the authority the launch nuclear weapons >.

[@darthguilder1923]

I'm down for nuclear spacecraft

[@omegasrevenge]

A good amount of rockets still explode during launch. This one would put nuclear fuel and radiation everywhere into the atmosphere.

[@manny655321]

Your channel is my favorite right now. You are a genius.

[@metalskirmish]

i keep watching 2 minute to 5 minute videos by these different scienceyish channels, and have to go watch old sfia videos for the real in depth look. cant get enough man. always thurough, and never boring.

[@somerandofilipino6957]

Speech impediments give the narrator something akin to a personality, anybody with me in this?

[@sirdouglashowel5thseat776]

the sound of confidence, it's rare in this world.

[@InquisitorThomas]

This Liberal Shithole Over my time I've listened to people with Russian accents, Chinese accents, Irish accents, Romanian Accents, Scottish accents, Japanese accents, English accents from the most posh to the heaviest north, Australians, Austrians, Swedes, Norwegians, New Zealanders, etc. etc. I wouldn't even notice his speech impediment if he didn't bring it up.

[@Mayordomo32]

No matter how much I try I just can't quite get used to it. Love the content, can't handle the audio, no disrespect.

[@spoton6010]

I have to agree. I love the concepts he covers, but with no disrespect meant, his speech impediment is too distracting.

[@Mayordomo32]

I can only hear "Oeth" instead of "Earth" so many times, a man has his limits.

[@sithlorddread8721]

I love what you do!! Cody's Lab brought me but your content made me stay....for the longest time I thought you had a Cajun, Louisiana accent....thats how me and my family watch your show....KEEP UP THE GREAT WORK!!!!

[@aleggs6019]

New Isaac Arthur video? *pops popcorn*

[@Zman888]

don't forget a nice hot cup of coffe either :)

[@brbyington]

Today was the first time I've ever caught myself checking KZbin to see if a video had been uploaded. Worth it.

[@MachOverspeedsPlace]

Outstanding presentation. Proud to be a new subscriber. MachOverspeed

[@trikkinikki970]

Holy crap when did you get up to 85,000 subs Isaac? I remember when you were just reaching 20k or so back when I found your channel in September. I'm so happy your channel has been getting the attention it deserves. Thursdays are my favorite day of the week thanks to you. I know I fawn all over you and your videos every Thursday, but damn do you deserve it. :) PS I love your consciousness and identity series of videos I would love to see another one of those, or to touch on parallel universes.

[@isaacarthurSFIA]

Thanks Nicole :) It's been a fairly steady growth with a few bigger bumps, I got about 5k new in a couple days after Cody of Cody's Lab gave me a shout out a couple weeks ago. I'm not sure what the time line's been except that I hit 10k a couple days before the Post-Scarcity Civs episode at the beginning of september, we had some fast growth that month two I remember. The rest is kinda hazy, I always feel a little shocked when I think about how the channel's been growing and the last time I calculated how many folks were listening to me at any give random moment of the day I actually got a pang of stage fright. Anyway next week's episode, the Douglas Adams tribute one, "Infinite Improbability Issues" goes back to discussing consciousness and identity a little, the was more but ended up cutting some of it because it came off a touch tangential and morbid. I decided to save it for another day when it was more pertinent and a little more cheerful, but that whole episode is on parallel universes.

[@raitheon]

@@isaacarthurSFIA look at u now closing in on 1mil:)

[@jamesmeritt6800]

An SF I read had an Orion-type drive and one person. She thought “it sounded like God was knocking on the door and he wanted in BAD!! “. I really loved that description.

[@caav56]

"Footfall" is the name of this book.

[@taotechnique]

What is Isaacs educational background or area of special interest? He's extremely intelligent. I could ( and have been) listen to all of his videos all night long.

[@isaacarthurSFIA]

The '100k subscriber special episode' covers a lot of that biogrpahical stuff.

[@Atrahasis7]

Btw you should play Children of a dead Earth Isaac. I bet you will love it when you make your first machine gun ailgun of nuclear projectiles.

[@MegaAnderson511]

Literally the best thing that has happened on youtube! Keep up the good work bro.

[@GeraldMMonroe]

Major factual error at 11:16. A solid core nuclear rocket explosion is very bad for people on the ground. The reason is that while U-235 _before_ running in a reactor is cold, after a minute or 2 of full power (while the rocket is ascending), it will be highly radioactive. It's no longer just U-235, but hot with a witch's brew of extremely radioactive isotopes created as both fission products and from the neutrons in the engine transmuting things. If the rocket explodes, it's a significant problem, comparable to the hazards of the last 2 major nuclear accidents. People would die, and the radioactive plume of rocket fragments would contaminate a very large geographic area. And as you point out, because to get high efficiency you need to run the solid core nuclear reactor as hot as possible, and to keep it as light as possible, the risk of explosion would always be unacceptably high. Such a rocket is fine as long as you launch the fuel cold and only use it in space in orbits that won't decay back to earth if something goes wrong.

[@soreff]

Yes, and similarly the main problem with the open loop gas reactor (if it can be made to work!) is the release of the fission products, not of the uranium.

[@soreff]

(I also should say: I enjoyed the presentation, and wouldn't call this a _major_ error in the sense that the bottom line is that once a fission reactor has been used, the fission products are a big radiological hazard, and the fact that a cold unused reactor core is basically harmless is largely moot) (FWIW, I support the use of ground-based and deep-space-based nuclear power, but rockets will always occasionally crash or explode, so I'm not thrilled with fissioning reactor cores lifting off from Earth-ground-based spaceports)

[@GeraldMMonroe]

Reason I said major was that de facto, the main reason you need high acceleration on a rocket is to leave the earth (or other planet). Interplanetary and interstellar journeys, fairly low acceleration is sorta ok. Admittedly, designs that go for very high ISP will need to be pushed to the limit to get adequate acceleration - doesn't do you any good if your fusion rocket gives you 1 million ISP if you need 1000 years to burn through your fuel. Nuclear thermal's only advantage is acceleration. For everything else, nuclear electric or direct fusion or other exotic methods are better.

[@josephstalin9939]

@isaacarthur

[@HuntingTarg]

Not disagreeing with anything already posted; I don't see a huge hazard with launching a solid-core nuclear rocket like NERVA atop a huge chemical ascent vehicle, then starting up the nuclear rocket in upper atmosphere to achieve orbit. The core is not a radiological hazard until it is activated. However, a device that heavy would be very difficult to lift off the ground (thinking the NASA Orion vehicle (the new one, not the nuclear one) or Buran-Energia with the NERVA in the shuttle cargo hold - if it can handle the weight and stress, that is).

[@brainwashingdetergent4322]

I just thought you had a southern draw I wasn’t familiar with. Thanks for taking the time for making a video on a complex subject and putting it in layman’s terms.

[@jasonmaxwell9762]

Isaac Arthur you are the best! And I love the way you say anti Madore!!!

[@floppypancake]

Hi there! Just wanted to say I discovered your videos and I think they are fantastic. Great stuff! I could listen to these for hours, and probably will!

[@Horesmi]

*hides in a fridge*

[@Rick-il3vn]

Is this a fallout 4 reference?

[@Horesmi]

It's an Indiana Jones reference.

[@jacksonreid4824]

It's both

[@Rick-il3vn]

oh ok

[@daxwax1]

That intro/outro music is awesome and another great video. Have loved the idea of nuclear powered rockets since I heard about the 'Pluto' nuke-deploying atomic death plane the US designed lol

[@MrMartechi]

It seems like nuclear-powered spacecraft would be the ideal solution for interplanetary travel in the solar system without a massive supporting infrastructure like the one laser-powered photon sails would need. And if we ever get fusion engines, experience from using nuclear fission would come in handy for sure. If I am not severely mistaken, it seems like torch-ship-like engines based on fusion power work much the same way the nuclear designs do - ignoring a ton of engineering details of course. What intrigues me the most about these designs is their size. Even relatively early concepts of this propose massive ships and it seems like the design would even benefit from using large vessels that can utilize larger reactors.

[@bozo5632]

I've finally watched the whole backlog. (1.25 times.) I got lucky and accidentally saved this one (one of my favorite subjects) for "last." But when this one's over I'll have none. Kinda sad. More videos please.

[@ppcgnamda]

I don’t think anyone has ever had a hard time understanding you. I’m glad you dropped the disclaimer in your newer videos. And as always - excellent content.

[@binkymagnus]

"The design is so simple you could bang one out in your garage, assuming you don't irradiate yourself to death."

[@YodaWhat]

Just load the fuel robotically, after all the other work.

[@dwavenminer]

YodaWhat just remember to harden the electronics of that robot, don't want the bot also 'dying' from radiation...

[@wowplayer160]

I don't care how you sound nor should other people but quality videos is where it's at. You are really good.

[@FerrowTheFox]

It's a shame nuclear has a bad reputation with the general populace (who, sadly, don't understand much of it...). I've been a proponent of NTRs for years, and while I agree we may want to be careful of using them for launches, they'd be perfect for orbit to orbit ships. We should at least try them. As others here have said: No guts, no glory!

[@jamesmeritt6800]

FerrowTheFox: and all those idiots protesting when Galileo made its gravity assist pass by earth!

[@spaceman081447]

@@jamesmeritt6800 RE: ". . . and all those idiots protesting when Galileo made its gravity assist pass by earth!" What? Why would they protest that?

[@epion660]

@@spaceman081447 "Stealin' muh gravity!" I don't actually know if this was the issue, but I wouldn't be surprised.

[@crazy8sdrums]

A very interesting and well-researched video! Thank you Isaac!

[@johnsteiner3417]

Honestly, I think you're speaking clearly enough that closed captions aren't needed. Don't let anyone give you shit otherwise.

[@valerierodger7700]

I've listened to over a dozen of his videos so far, and there's only being one time that I didn't catch a word at first. Some people just need to be negative, I guess.

[@johnsteiner3417]

@@valerierodger7700 I've listened to some shit narrators on here, but Isaac Arthur does really well.

[@arclightecho420]

You're amazing. Thank you soo much! Never stop! All my love and good will to you sir!

[@joaosturza]

have you consider making a upwords bound about baloons? taking them high up and lunching form high atmosphere with much less fuel

[@joaosturza]

but its just an idea

[@isaacarthurSFIA]

Yes but I've decided to remove it from the main sequence, I've been trying to get through all of those fairly quickly and doing every other episode in Upward Bound is getting a bit creatively stifling, so we've got three more in this series to be done before July and then will revisit it to cover others as circumstance permits.

[@joaosturza]

right

[@joaosturza]

one thing id like to see you cover is more biological,political or" human" stuff as most of your channel is physics or engeniering based

[@joaosturza]

also im just gonna share this about the slingatron,from kick starter it was an intresting proposal and i belive its intresting enuff to add to the video on it, joerge sprave

[@advancedcavemen4104]

This is my favorite channel on youtube.

[@williamcullen2536]

Like a boss

[@wiros8101]

I would like to see a video on nuclear power, please do that! No rush though, I know your busy because every one of your videos are better than TED talks(and I love TED). Great work!

[@robertmiller9735]

Using nuclear propulsion to launch from other planets-that don't have ecosystems to damage-would be extremely handy. While the best example is Zubrin's NIFT, that uses Martian carbon dioxide as propellant (land, spend a day while the tanks refill, take off again), my favorite idea is a CO2 nuclear-thermal ramjet for Venus: about the only way to design a shuttle for that planet. It wouldn't land, of course; just keep on flying.

[@cassgraham7058]

Except you also have to account for cooldown time for the reactor. He didn't go into this, because it gets long fast, but the entire reactor isn't shielded, just the bit facing the ship, because shielding is heavy and screws with your center of gravity. Disembarking from a nuclear powered rocket is likely to be tricky, unless you sit inside for a couple weeks or so before you step out of your ship.

[@HuntingTarg]

The biggest problem with using nuclear technology in space isn't radiation though - it's the problem of how to dissipate all that heat. We have enough difficulty with batteries and RTGs, to the point that many solar arrays double as radiators. The ONLY way to discharge waste heat in space is by radiation (no, not nuclear radiation, thermal radiation through the photoelectric principle), and that requires a good material and a lot of surface area (Gold is the best, aluminum and silver are runners-up).

[@YodaWhat]

@@HuntingTarg -- The first 350 or so characters of your post were exactly right, but after that, exactly wrong. After "... not nuclear radiation, thermal radiation" you ran off the rails. The photoelectric effect has nothing to do with thermal radiation. The principle you want is *_blackbody radiation._* To do it, you are best off with *surfaces that actually are black (good thermal absorbers) at the wavelengths you want to radiate.* See hyperphysics.phy-astr.gsu.edu/hbase/quantum/radfrac.html#c1

[@ATLTraveler]

Good for you for making a super successful channel with you being the narrator with a slight speech disorder. My best friend in middle school had a studder and he was so self conscious about it, I always told him that he sounded fine and not to let other people bother him. Kids would laugh in English when he read aloud but I always had his back. Kind of off subject, but I just know how it can be to have a speech disorder, so it makes me happy and proud that you have the confidence to be a successful narrator and followed your interests without letting it hold you back. Keep it up dude and never let the haters get to you.

[@HankScorpio]

I always love these videos, and I was so happy when Issac mentioned Nuclear Options last week. I thought the main focus would be nuclear pulse propulsion and the Orion project. I felt that he greatly skipped over to much of the detail and dismissed the idea to quickly. Some of the more important nuances of project Orion such as the nuclear bomb released is encased in a shroud to focus the blast toward the craft / away from the earth, greatly improve efficiency and mitigate nuclear damage to the environment. The spaceships would be loaded with different yields of nuclear payload, in order to change as required for in atmosphere, or in space use, as well as acceleration and deceleration phases. Additionally a full size nuclear pulse spacecraft at maximum weight would still only need 5 or 6 detonations before it is above the atmosphere or at least above the height where blasts would be harmful at the surface. If you launch the craft above a blast hole, the initial detonation can be much larger and get the rocket up to safe height quickly. There are so many places in the world under-inhabited when such a nuclear launch could take place without far for the locals. As for safety concerns, most of the nuclear payload could be jettisoned into safe landing parachute cases within seconds of any serious problem detected. I feel like Issac did a disservice to a great and innovative idea by brushing over it so quickly. I hope he comes back to this topic in a later video./

[@isaacarthurSFIA]

We've discussed Project Orion before, I wasn't skipping it, just skimming something we've already covered elsewhere a few times.

[@thatdude5931]

I know its a touchy topic, but it might be a good idea to do a video on nuclear power, going over the safety concerns and what we can do to alleviate some of the larger concerns and what we can do/ have done to prevent them.

[@D0t0ne]

Isaac, I am a big fan of your channel although I must admit I dont have even slightest of clues about most of the stuff you talk about in your videos. Having said that, I am left with a lingering question, actually several but the most pressing one is that you talk about things as if they are already established facts. After listening to you I just can't understand why we are not already travelling on interstellar journeys since we have all things figured out. I really enjoy your videos, for a moment it makes me feel that we are already going to other stars. Thanks.

[@flyingeagle3898]

We don't have everything figured out. Far from it. However we do have a lot of basic things figured out, and know what designs are within our abilities with current technology, or could be developed if we put money into it. However the concerns with safety of launching large amounts of nuclear material are no joke, when our current rockets have a failure rate of 1-5%. That kind of likelihood of nuclear material falling all over the place is just not something most people are willing to accept. Some of the safer methods of nuclear propulsion could gain acceptance, especially if they are used only in deep space, but getting fusion to work would still be far better.

[@isaacarthurSFIA]

Well mostly complexity and risk, I try to simplify the ideas here a lot so it can sometimes give the false impression that actually getting these things running can be a bit of an engineering nightmare. All of which adds to the financial and human cost, the latter tends to worry governments more in a lot of ways, since blowing up national heroes on live TV tends to be murderous on national morale. We can definitely do this stuff, and we make continual progress, but its slower than a lot of folks would like especially against the backdrop of computers and smartphones which seem to constantly improve.

[@danielhall271]

There are some very good reasons why we don't actually do these things and they deserve an episode all to themselves. So how about it Issac Arthur? An episode or series on why we don't do these things and all of the things standing in our way.

[@D0t0ne]

As a species, its truly sad to see that we are so short sighted that we can not see beyond our life times for the most part, politicians are the worst offenders as they can not see beyond their terms. I hope one day humanity can rise above petty issues dividing us and start looking at things that unite us. Then may be, just may be we can venture into the galaxies far far away. Again appreciate your work a lot, keep on making these videos, it helps keep the optimist alive in us.

[@D0t0ne]

At times I feel we are a suicidal species which is hell bent on destroying our selves. I can not comment on effects of Nuclear weapons in space but when it was banned there was a sound scientific reasoning for it. But if by some miracle humanity can reach a consensus regarding this, we might see them. But its a BIG IF.

[@peterknowles23]

I love the way Isaac Arthur speaks! But more important than that I love the subjects!

[@andreassjoberg3145]

By the way, during your time posting theese videos, I've noticed that your speech impediment have improved. Your pronounciation is much clearer in newer videos.Practice makes perfect - Keep on posting!

[@slcontent9465]

Your series reminds me of a modern version of carl sagen`s cosmos ... good work issac this channel is so good !!!!!

[@Mayhemspent]

P E R F E C T T I M I N G

[@CarlosAM1]

?

[@kerryevans7283]

I love your voice it's so soothing, it makes your videos relaxing. Interesting, informative and relaxing. Perfect way to chill out before bed.

[@darvexa7830]

I love your videos

[@kobayashimaru8114]

I really enjoyed that, thanks. You're actually a very good speaker.

[@highlandrab19]

doesn't breeder fission produce no radioactive waste so surely we should be using that for now until we get fusion

[@isaacarthurSFIA]

:) The bred material is the radioactive waste, but you still have other types.

[@highlandrab19]

but if the waste material is plutonium surely we could keep feeding it back into the reactor until you have waste with a very short half life.

[@AndDiracisHisProphet]

It does, though. I don't know where this misconception comes from.

[@TCBYEAHCUZ]

AndDiracisHisProphet he's applying earth based reactor arguments to a space rocket. i.e. the breeder reactors are better or good because they consume nuclear waste that more primitive designs made.

[@SpydersByte]

man the graphics and sound on these videos are always amazing. That 'Sirius' track is so good, reminds me of Mass Effect when I hear it.

[@jamesfra1311]

*THE FUSION DRIVEEEEE*

[@swedensy]

Or fission, i dont understand. When it comes to science people should one language.

[@ArgentavisMagnificens]

Just found your channel and subscribed! All of videos discuss awesome topics, and have amazing thumbnails too, now I want to watch all of them haha Great video. I see a great future ahead of you. Best regards!

[@Netist_]

"Add a neutron to Uranium 238 and you get Plutonium 239." Don't you mean a proton?

[@isaacarthurSFIA]

No, a neutron, you're right that Pu-239 has one more proton [and electron] than U-238 but is otherwise identical, but that neutron we add becomes a proton, an electron, and a neutrino.

[@AndDiracisHisProphet]

No. Technically, when you add a neutron you first get Uranium 239, but that decays quite quickly via beta minus decay to Plutonium 239.

[@unvergebeneid]

"that neutron we add becomes a proton, an electron, and a neutrino." It also gets a transmutation badge.

[@isaacarthurSFIA]

Yeah, I suppose if we want to be accurate I shouldn't treat it as a free neutron decay, it goes U239->Np239->Pu-239, and Np-239 actually last a couple days, and either way we can't really say it is 'that' neutron anymore.

[@garethsmith7916]

I've been waiting for a good video about nuclear propulsion for SUCH a long time.

[@BandytaCzasu]

I'm too drunk to comprehend this.

[@sol029]

Can't believe it's taken me this long to stumble across this channel. Brilliant stuff. Thank you Isaac. KZbin needs to push content like this instead of the nonsense it pushes typically.

[@yoloswaggins1579]

Temprahchaww = Temperature Ayaw = Air No offense, keep it up.😆

[@juangallego7197]

This video just came up on my suggestions, and it's absolutely brilliant.

[@AstroFocus]

Do you think a nuclear war is what is going to kill mankind?

[@TheLegend-nj3gk]

Nice vids btw. Yeah its like a child with a gun ;)

[@Edenssunlight]

are they funny? what if we are the one that are funny? what if the funny thing is that they are really trolling and baiting us? Now that would be funny wouldn't it? maybe their capabilities are far superior to what our intel believes it to be? that too would be funny.. After all taking into consideration the accuracy of the information we have used and acted upon in our past doesn't exactly have a great track record.. that's pretty funny too.. I can go for hours on pointing out what's funny.. but honestly there really isn't much funny about war and death no matter who it involves... you can take my word on it or ask any other person that has been in a war and not watching one on KZbin or through our bias media playing on our flat screen television thousands of miles away from any reality of what's going on... So yea.. nothing funny at all about North Korea's threats..Absolutely Nothing..

[@pyroromancer]

they dish out threats every year around the time collab military drills between S.K and US are going on, The last time something actually happened a S.K ship was sunk by a submarine who's affiliation has yet to be identified.

[@jort93z]

I dont think its funny at all. North Korea has a bigger military then you'd think.

[@chuckbuckets1]

funny as two cannibals eating a clown...

[@kissmybass663]

Just found your videos, they are awesome. Thanks for the info, I could listen and watch these videos all the time. Keep up the awesome work.

[@_BLACKSTAR_]

If you can raed tihs sctenene, tehn you soluhd hvae no plerbom uaedtsndrnnig waht Isasic syas.

[@josephstalin9939]

black star Peak

[@DarthCuddlefluff]

Having gotten used to your Rhotacism I find your voice conveys a genuine, and impossible to fake intelligence. You enrich my imagination with these videos. Thank you sincerely +Isaac Arthur

[@plopping-wetlyacademyofmot9639]

Wow, the like to dislike ratio is a great indicator of how high quality this channel is. Thank you for making these great videos!

[@mirage3rd]

Thanks for a series of GREAT videos