Author's Note: A bug and and error, so hit like to help keep this comment at the top. Error: I botched a unit conversion on the EmDrive results, re: thrust in terms of Force per Power. The units were in mN/kW for the table I was using and I think I mentally replaced 'milli' with 'micro' since all the results from eagleworks were in micronewtons. This is annotated on the video now but those annotations aren't visible to folks on mobile devices so I wanted it visible in the comments. Those early results are of course very tentative but I still botched my math. Sorry. It's not the first and won't be the last error, and it's not terribly pertinent to the discussion, but it is still a big math screw up. Bug: There seems to be a lot of issues with the closed captions about halfway through resetting to the beginning, but the transcript file and timing are correct, so it's probably a bug, but refreshing seems to fix it. [Fixed now, some weird bug crammed the first ten minutes of the script back into the middle of the episode, I had to manually redo the timing so its probably a hair off]

Your speech is easily understandable, my friend. You're just fine.

Anything more comforting than Issac saying 'grab a drink and a snack before I start' what a legend! Keep up with the fantastic videos my friend 👍🏻

Quality and Quantity never thought i would see something as good as this channel

Table of Contents 10:20 Laser Sail 12:25 Nuclear Propulsion (Daedalus Fusion Engine) 12:45 Nuclear Thermal 13:57 Nuclear Electric 14:22 electrodynamic tethers 15:08 ion Drives (15:45 Hall, 17:09 VASMIR) 20:45 Anti-matter and Other Photon drives 26:25 Laser Highway 27:10 Diametric / Pitch and Bias 27:54 Bussard Ramscoop and Dark Matter Drive 28:33 Em Drive

He was right about the EM drive stuff. Since this video was released it has been fully confirmed by consensus and peer review and all of the proponents of EM drives that the tiny bit of thrust was due to outside influences I believe one of the main ones was literally momentum created by the electrons travelling through wires, crazy.

This is a rare "Snack and a Drink" episode, as opposed to the much more common "Drink and a Snack" episodes :)

Mate, you really don't need closed captions because of your speech impediment. I love your videos and find your knowledge mind boggling and fascinating. Your videos are my go to choice at bedtime. I love relaxing and ingesting your fountain of knowledge. Even if I do struggle to understand some of it. Keep up your great videos, us mere mortals rely on you for our fix of space and the unimaginably huge universe that we live in.

9:39 You don't move the earth when you jump you introduce a pressure wave into the ground and the mechanical energy of that pressure wave is dissipated as heat or is invested in compressing mass. When thinking about the physics of the earth people often make the mistake of treating it as homogeneous and totally rigid no planet sized object is rigid enough to be moved by a person moving, you're more likely to introduce flexion into its structure. P.S. I discovered your channel today and I love your work and how your brain works. You're so thoughtful, thorough, considerate, and intelligent. I've loved testing my fiction universe against your conclusions and looking at it even more critically. I haven't caught a significant shortcoming in it yet and I hope my winning streak continues. Edit: made compliments sound more genuine.

so nice to find a channel that can just impart valuable and enlightening information without the need to be geeky and zany. I've grown quite sick of clicking of space news vids to be hit with zany child like presenters. Any ways a great video that seemed to prempt the questions arising in my head. You forgot one important type of engine...The infinite improbability drive! i've subscribed, cheers.

I'm not finished with my video but it should be out in a couple hours. ok maybe more than a couple...

If we crack fusion it'll be like discovering actual magic...

Don't worry about your speech impediment. It's a very minor thing. Thank you for the video.

do people really have difficulty understanding you? I find you easy to understand.

I already know this video is awesome, cuz i saw the script! thanks for making this Isaac it was alot of fun pitching a topic for your awesome channel!

This is the only channel where videos over 10 minutes are actually quality enough to watch the whole thing.

Your videos are educational and very fun to listen to. I find them calming and very interesting. The conclusion pf the video regarding how journalist publish everything is very true and has made me more aware of what I read and what i take for fact. thanks again.

Your channel is awesome! I have been watching you for a while and have noticed that your subscribers are growing very fast. Congrats on the success. Hope the channel gets huge and I cant wait for the next video. Keep up the great work!

Sir after watching just one of your videos I was hooked. No lie. I leave your playlist going all night while I’m asleep and then when I get time through the day I watch them again. The way you impart the technical knowledge in a manner that is both easy to understand yet doesn’t sound demeaning to the listeners is brilliant. I became a subscriber instantly and look forward to everything you put out. Well done sir

Its unreal that so many videos of this quality is posted for free on KZfaq. WOW. You deserve a super-massive raise my friend! Your series is worth millions for sure.

Damn, I'm so glad I found your videos. Not only are they so thorough in research and content, but also captivating, Nice Job!

Hey Isaac, I started watching your channel a few weeks ago. I know in a few videos you mention your speech impediment. I have to say, after listening to a few videos I don’t really hear it anymore. I personally find your voice very soothing. I am glad you do what you do. Keep blowing minds.

I've watched every single one of your videos...and I can't get enough. The quality of your videos are on another level compared to other similar videos on youtube. Please continue what you are doing I am sure to say we are all grateful!

Honestly Mr Arthur, you are one of the great minds of our time, I do hope more people get to appreciate the brilliance of your work

I do enjoy finding absolute gems of channels amongst the dross that is youtube. This is the first of your videos that I've watched, and it will not be the last. Superb, absolutely superb.

I do wish we'd start actually using some of this stuff. At 2 gee accelerate/brake, the Moon is only 2.5 hours away! It's a bloody day trip.

I freaking love this channel. Stimulating the mind one video at a time.

Not only is your speech understandable, it is downright comforting. Love the videos.

got sent here by a video plug of cody's lab and i must say sir i am thoroughly impressed, +1 and subbed

This makes me want to go play Kerbal Space Program

What's most amazing to me about you and people like you, is that you are what I would consider normal and I, unless watching a video where you are explaining things to me, am somehow substandard. Absolutely fascinating. Not just the material you cover but the fact that you could make a brain like mine understand it. Thank you so much for uploading!

Stumbled into your channel about a week ago, love it I watch these everyday, thank you for the work you put in.

Longer the better. Great vids.

17:22 Never thought that Franklin Chang would be that important in rocket science development, he is from my country though.

This is one of my favorite videos out there. I’ve listened to it many times and based an awesome science report last year on it.

After 10 years watching stuff on KZfaq, the genuine awesomeness of your channel has motivated me to hit "subscribe" for the very first time. Thanks a million for the mind-tickling info & visuals, and for the time & work that go into it. Ever since I first learned about the acceleration of the universe's expansion, I've been pretty bummed out about our long-term prospects, but watching your videos makes me think our descendants will actually have plenty of time to experience plenty of cool stuff we can only dream and muse about. And for that, too, I thank thee. Godspeed!

fission fragments thruster eactor

watched a few of your vids now... subscribed :)

This channel is like the perfect channel for me. KZfaq needs more people like you.

I did not notice anything even after you mentioned it. You are much clearer and understandable than many KZfaqrs if anything one of most clearest.

ahh yes, Project Rho. It's like the Home Depot of rocket science- you just want to use _everything_.

ou play kerbal space program? i imagine a nice side project of you and scott manly talking about space and stuff

Your videos are very interesting. I love that you're tackling these things. The sort of stuff you tackle is exactly the stuff I love seeing.

One of the best channels on KZfaq. ..without a shadow of a doubt.

hold on, you can keep getting acceleration from a laser beam between two mirrors? Shouldnt the light degrade to lower and lower energy, via longer wavelength, until there's no more force to impart? How long could that go on?

Hey, I just ate some eggs and doubled my exhaust velocity ! : D

I love this channel! LOVE LOVE LOVE IT!! I sometimes get so engrossed in the topic that I forget to hit the "like" button, but as I sit here sipping tea from my Isaac Arthur mug, I LOVE THIS CHANNEL!!

I realize this is 3 years old but I just found your videos and I'm loving them.

EM drive review paper was released do a video!!! please

It's almost 2018 and the Em drive is still in the 'unproven' category. Any sign of a resolution or is this going to become just another cold fusion type claim?

Thank you for doing what you do, please never dumb down or shorten your content to fit the internet age attention span. It’s so rare to find science based channels that aren’t superficial clickbait at this point.

Great combination of sound, voice and visuals. I'm hooked.

Either your speech has improved, or i got used to it :) Anyway, nice video, and the whole channel really, thanks for your work!

Your speech is fine buddy anyone says different fuck them good job mate.

So pleased i've found your channel. Awesome content and thanks for explaining things so clearly!

Gawd, I just stumbled on these videos recently --my bad! These fantastic nuggets of information are what I hoped the internet would be all about. Bravo Isaac and many thanks for your great work!

Take a look at thorium reactors. Either molton salt reactor or liquid flouride thorium reactor.

Did NASAs EM-Drive really have less force/power than a photon drive? I thought it was at least an order of magnitude more which is why people got exited.

subscribed with an open heart! love your music choice and technical knowledge!

Great Job Isaac.I Actually didn't even knew you had a speech impediment. Your science is good, reading and narrating skills, GREAT! I love these videos. Keep em coming!

I'm a bit confused that you did not mention more "down to earth" propulsion methods, already doable or almost doable with our technology. My favourite being "steam rocket", a rocket that carries it's own reactive mass but gets the energy elsewhere - most likely ground-based power plant. That would not make it much more efficient in therms of specific impulse, but make it much cheaper. Your rocket will not be a super-complicated masterpiece of engineering powered by highly-refined fuels, but rather a big tank of liquid hydrogen (or even plain water if you can dump enough power quickly enough into it) with some basic exhaust vectoring coated in absorption material. Then you focus high-powered laser or maser on it to get the contents boiling and have a nice thrust. Naturally there are some drawbacks, like problems with atmospheric scattering of the laser\mazer beam or that you need the line of sight with the rocket at all times. But it seems like a reasonable first-stage engine, mostly because of the costs. Alternatively it can be used in asteroid mining - you would have a relatively large fission reactor or solar farm on your asteroid colony and on Earth orbital spaceport, and you can send dirt-cheap transport ships that are just ice-filled tanks with some cargo attached between those. It's not the most efficient way, but it seems to be a lot cheaper one.

Speech issue? Over it... within first viewing. I've worked with some of this worlds smartest people. A speech impediment ranks low. I liken it to a coworker who thought in parallel, and had problem trying to speak serial.

Found a new channel to binge through! Thanks, Isaac!

This is brilliant, intelligence, narration skills and the ability to keep things interesting are what defines this not your voice! Keep at it bro you rock

Yes please, GET INSIDE ME!

This is an idea I have been trying to draw peoples' attention to for decades. It does not use advanced technology. In fact the fuel I selected is considered too slow for an advanced propulsion system today. It is UDMH and the oxidizer is N2O4. Both these liquids are storable, though, and that's why I selected them. Basically the idea is to use the C-5 airlifter as an efficient first stage for a rocket to orbit. The C-5's basic maximum payload of 240,000 pounds is bypassed, and a rocket massing at least 400,000 pounds is air dropped from the equator at an altitude of 25,,000 feet. The rocket that is loaded on the C-5 has a mass of 150,000 pounds, including 125,000 pounds of UDMH (unsymmetrical dimethyl hydrazine the fuel used in the Titan 2 ICBM). The plane then flies to the equator, burning about 300,000 pounds of its on board fuel plus a refuel by an accompanying KC-10 tanker if needed. A specially modified KC-10 then rendezvous with the C-5 and transfers 250,000 pounds of nitrogen tetroxide oxidizer through the aircraft pumps and into the empty oxidizer tank of the rocket. The back clamshell doors of the aircraft are then opened, after it has slowed to about 220 knots. The rocket, now massing 200 tons is extracted out the back of the cargo bay. At a safe distance ( a 2,000 foot drop) the main engines are ignited. In all the simulations I ran this rocket can deliver from five to six tons of payload to a 300 mile circular low Earth orbit.. The turn around time on the C-5 aircraft should be only a few days. It would be the only part of the launch system recovered, unless a manned rocket was the payload. A six ton payload is not much. The selling point would be that many such launches could be made per year. At one launch per week the system could put up 300 tons of payload per year.

I absolutely love your videos. Please keep up the good work. Once I'm done bleeding money for school, I'll definitely be donating to your Patreon. I've watched all of your videos, and we need more people like you.

Isaac, you’re amazing, When I was just new to your super approach, I was awed that you were so well versed in the physics that controls us, and you’re the run-a-way whizz-

By far one of your best videos thus fat Issac, thank you for providing us all with such brilliant content!

Thank you for making these videos. I really appreciate it as it's interesting and gives me something to listen to while at work during my monotonous day.

4 years later, having been through all your videos, I now put these on when I want to grab a nap and a think. No irony whatsoever, your voice is basically my white noise machine these days. Wish I had you to whisper in my ear between QRF shifts during OIF lol.

Isaac- great coverage. The narration's outstanding! Thanks for a decent summary.

Thank God I found this channel ,it answers all the questions I've been asking for a long time

I love you Issac Arthur. Best videos to go back and binge watch again ❤️

Fantastic episode. This has to be, by far, my favorite channel. Excellent work sir.

I love these videos. Very thought provoking and done with great detail and obviously a ton of research. Great job with all of these.

Isaac you speech is rather perfect and have nothing to worry about. You tell a great story so keep up the great work.

I find your speech to be easy to understand and really relaxing. These videos are my new thing for a relaxing drift off to sleep while learning.

English is a second language to me. I'm glad you mentioned your speech impediment. It is very light and never interfered with the ton of learning I'm graced with on your channel. I like how your theses are based in scientific principles. Keep it up

What a great video! I am fortunate to have stumbled onto this Video Channel, off of a link someone posted in a comment on a post on Facebook! Very Cool!! Thank you for taking the time to research and produce these excellent videos!!

The old vids audio is amusing now. Nice how far you've come

Isaac, i'am new to the channel and i've got to say, these videos are fantastic. Thank you

I have never had a problem understanding you, and it seems to be getting better.

Excellent presentation,best on this subject I've seen so far

These videos are amazing, your speech is easy to understand. Thank you

i love this channel, these topics are giving me great ideas for my story and I like listening while I'm working on art! Keep up the good work.

shit... Imma have a speech impediment before long. I've been binge watching for a week now and loving the topics.

Thanks for making great content and educating us!

I could listen to you talk all day. New favorite channel!

dude only recently found your channel and I'm hooked! amazing content with lots of sci fi references that help the average nerd gain a point of reference. it only took a vid or two to get used to your speech which is super clear. keep up the good work bud :-)

I can listen to you all day. I love your videos! Thanks!

Content and presentation, pure class.

Hi Isaac, finding your video's has been an absolute joy, the manner in which you deconstruct complex idea's and concepts is fantastic. Please keep making video's! Cheers, Sam

Hey Issac thanks a bundle for always giving the real lowdown on future tech!!

I can understand you because my youngest brother had the same speech impediment until he was 11-12ish but it’s so cool and polite of you to provide CC. Love your channel man.

Logic demands I give you HUGE praise for your EXCELLENT survey of all these different types of potential or real propulsion systems. Kudos! You clearly know your stuff VERY well. You are NOT one of these idiots who completely ignore basic thermodynamics & conservations laws: energy, momentum, force balances at points. I know I am nihilistic (my other comments) - but I am always hoping/waiting to change if others can prove to me otherwise.

Hi Isaac. Just discovered your channel. Full of interest. Just need time to watch them all. I find your voice easy to understand, unique and interesting. Thanks for your hard work.

Fantastic content. Well laid out and enjoyable. You've got yourself a new sub.

I love your channel I listen everyday as I get ready for bed so I can think of something positive. Thank you for the captions I enjoy captions on everything, although you're easy to understand without them. Your content is great!

Thanks for doing these. I've been a sci-fi geek since I was little and now that I've started writing sci-fi shorts, you're an excellent reference on the tech end.