Why Next Generation Rockets are Using Methane

ULA's Vulcan rocket will be propelled Blue Origin's BE-4 engine and spaceX's next generation engine is the Raptor. Both are using Methane as a fuel rather than RP-1 or Hydrogen - so why is methane suddenly an ideal fuel for rockets after largely being ignored for half a century.

[@RyeOnHam]

Two additional advantages not mentioned: 1) Methane is SIGNIFICANTLY easier to store in space and does not boil off like Hydrogen. 2) Methane and LOX store at similar temperatures meaning you can use a common bulkhead and reduced the structural weight and insulation requirements.

[@adamp.3739]

FUCK YEAH! **fires shotgun in salute** #MethaneFTW

[@mandernachluca3774]

For your first statement, RP1 has the same advantage, that's why the Saturn Vs first stage burned RP1 and the third an second stage H2 ;D.

[@Boomchacle]

yeah but so is literally any fuel other than hydrogen

[@SuperCuriousFox]

Mandernach Luca The Saturn Vs first stage never made it to orbit or space, even. I don’t think that’s the reason they chose RP-1 for the first stage.

[@CarFreeSegnitz]

boomchacle It would be possible to choose a fuel that freezes solid at the same temperature that oxygen is liquid. And solids are a pain to shovel into the engines.

[@Boemel]

Why am I imagining a Scottish space program fueled by single malt whisky.

[@TheAmericanCatholic]

Tom Jacobs or a Russian space program powered by vodka

[@clewerhillroad]

SMTO - single malt to orbit?

[@donjones4719]

@@TheAmericanCatholic An early Russian rocket (a big one) was fuels by ethanol... alcohol derived from potatoes, 95% pure. Yes, super-vodka. They had to denature it, make it poisonous, so the workers wouldn't siphon off half their fuel.

[@kcasc_hd]

burning 500000$ per second

[@into_the_void]

Aye.. the Glenfiddich space station will make whiskey in space..

[@sleepib]

Methane is also apparently easier to simulate with CFD than RP-1, because you don't have as many intermediate combustion products.

[@Czeckie]

fascinating! do you have any source for that?

[@delayed_control]

The simpler the gas, the more accurate the simulation. You don't simulate individual molecules in CFD, that's impossible

[@nachtgecher]

With Kero you don't need CFD when you've got Ivan.

[@sleepib]

Each unit volume can have a different composition though, and may have many component chemicals.

[@abhishekkushwaha100]

@sleepib Do you know how to simulate the combustion product of rp-1??

[@mtparkourartist]

Scott, ive been watching you for a long time. 6 years. While i havent been a frequent viewer, when i was younger i would come to your videos for knowledge about rocketry and kerbal space program. With your videos you opened my eyes to the world of science in ways no teacher ever did. You made it look fun, more importantly you were doing calculations and science for fun! It wasn’t for a job, you were just calculating how much delta V you would need to go to Duna or whatever. It really inspired me to want to become an engineer. I am starting my education and i would really like to make a positive impact in the space industry one day. You, and Kerbal Space Program, changed my life. Thank you for all the content you put out. You are changing lives.

[@Zonkotron]

And hold on tight son. University can be really great but also a right piece of shit on occasion. Simply because they can. It's like school but more extreme. Good professors are incredible. Bad ones will damn near try to kill you by teaching too much in too little time and doing it badly on top. Don't let that discourage you. Just try to not get hit and work with the good people as much as possible.

[@MillenniumEarl014]

Go and change the world, brother!

[@ClockworksOfGL]

Gofish - Your comment is a nice change of pace from the usual KZbin dumpster fire.

[@keirfarnum6811]

Gofish That’s really cool. It’s nice to hear about when people are inspired to do cool and interesting things. As an old and disabled person, I’m jealous. Wish you well.

[@vsiegel]

@Gofish - Thanks for thanking Scott. I think this kind of channel has quite a deep impact just in the way you describe. And somebody making a channel like this may vaguely be aware of that, but very abstract. Great to have direct evidence.

[@alphaadhito]

*F.A.R.T : **_Future Advanced Rocket Technology_*

[@jockeb2651]

I came here for the fartjokes. Yours was better then a really pleasant fart itself!

[@Mosern1977]

FART means 'speed' in Norwegian.

[@newsgetsold]

Flatulence Assisted Rocket Technology.

[@lipzi2]

Chemical_X_ and co nah that would be fahrt and not fart

[@TheJimtanker]

How very Kerbal of you.

[@FredericSimon]

From what I understood of the Raptor design, the full flow double turbo pump is to increase reusability. The single turbo pump generates a lot of issues by being used close to both the LOX and CH4. reservoirs

[@AubriGryphon]

This is funny because I'm in the middle of reading (listening to) Ignition! by John D. Clark. Between that and your video on Soviet-era engines, I've come to think of methane as "The Mario" of fuels -- kind of all-around good-but-not-great with no particular weaknesses. It's energetic, but not as good as hydrogen; it's reasonably dense, but not as dense as kerosene or the hydrazines; it's quite safe to handle, though not as safe as alcohol or kerosene; and it burns clean, but not as clean as hydrogen.

[@DrZond]

Yup, that's it.

[@Sacto1654]

While liquid hydrogen is a very good rocket fuel, it's also _extremely_ dangerous to handle, as Lockheed found out when they did research on a potential rocket powered spy plane.

[@AubriGryphon]

Well, I didn't put it on the list of safe materials. But let me put it this way: Compared to hydrazine derivatives, chloro- and fluoro- oxidizers, aniline relatives, and nitric acids doped with various chemicals, I would *much* rather catch a little frostbite. (If there's a big splash you're hosed either way, but again, the frostbite might be reparable.) And if there's a spill that doesn't directly hit anyone, hydrogen is *by far* the safest outside of alcohol and kerosene, since most of the other options give off heavy, toxic fumes in addition to being flammable and/or explosive.

[@Sacto1654]

A huge problem with liquid hydrogen is that when it explodes, it makes a natural gas explosion seem like a minor event. That's why Lockheed, whose "Skunk Works" tried to build a rocket-propelled spy plane fueled by liquid hydrogen, dropped the idea in favor of special turbojet engine designed to cruise at very high speeds: the original A-12 (which became the SR-71).

[@AubriGryphon]

@@Sacto1654 We're talking about rocket fuel. Large explosions are par for the course.

[@KMURPH311]

Scott, new to your channel and am very impressed. I genuinely enjoy your takes on the happenings in the Aerospace world. Keep up the good work! Cheers!

[@DavidTriphon]

"90s movement for a mars mission?" 7:09 _wordart infographic pops up_ "Oh yeah, definitely 90s."

[@johnfrancisdoe1563]

David Triphon That's PowerPoint, not WordArt.

[@supejc]

Thank you for your videos Scott!

[@zapfanzapfan]

8:57 Are all rocket guys bald? To baldly go where no man has been before? ;-)

[@texaswilliam]

It's all about aerodynamic efficiency. It's called a fairing, not a hairing. : P

[@stsk1061]

Technically, Musk would be bald aswell. He just chose to go down a different path :)

[@WineScrounger]

Hydrazine will do that.

[@cake6476]

Saves on mass

[@markgohl2660]

G-forces :)

[@DonTekNO]

I guess sharing knowledge like this makes the majority of viewers keep coming back for more of your videos. We are all on a journy to become even bigger nerds than we already are .....

[@baruchba7503]

It's actually against federal law to put this info in the public domain.

[@myrobotfish]

Damn, methane really seems like the happy medium in pretty much every category. Someone should try to make the most efficient engine possible with said fuel. Oh wait ...

[@angadsingh9314]

lol

[@ufuker5754]

İ think most efficient engine would be build by rocketlab or someone else that spacex I say it Will be like this electric pump feed for oxygen and expander cycle for methane

[@unepintade]

Engine wise the best bipropellant engine efficiency will always be obtained on one running LF2/LH2 for chemical rockets, and that's a much higher efficiency than any metholox engine could achieve

[@TheExoplanetsChannel]

So if an astronaut farts, he or she can say there has been a fuel leakage xD

[@CookiePepper]

Methane is odorless by the way.

[@ebolapie]

thanks melvin

[@Spudda]

You can use “they” as a gender neutral pronoun. No use in saying “he or she”

[@niaschimnoski882]

Yeah are you sexist against farts. Why would an astronaut lie anyways‽ They would get in teouble if they lied!!! (I'm trolling I know you was joking)

[@sandordaniel7327]

@@Spudda we all know women don't fart, that's strictly a male thing :P

[@flightsaitek4087]

I was going to mention on an older video that I heard that rocketdyne Aerojet was not going well, and I guess this confirms it. I heard the rocketdyne was getting rid of stock which is never a good sign. Interesting change over to methane! Great video covering this topic as expected, mad props!

[@wm012]

Please don't stop these wonderful videos.

[@MysticalDork]

Another significant advantage over RP-1 on long (interplanetary?) missions is that it won't freeze solid from close proximity to the LOX. No boil-off like hydrogen either. I remember Spacex losing out on a couple launch contracts to competitors with hydrolox or hypergolic upper stages because the falcon 9 second stage didn't have the endurance for a restart after a couple dozen hours because the RP-1 would freeze.

[@alanrym2160]

You forgot to mention that methane is much cheaper than RP1, what is important when reusing spacecraft

[@j.jasonwentworth723]

Anhydrous ammonia--NH3--is also cheap (it's used a lot in agriculture), and it leaves no residue. The X-15 rocket planes--particularly after the "big engine" (the XLR-99) became available in 1960--burned LOX and anhydrous ammonia. Ammonia fuel also has the advantage--if one wishes to call it such--of *not* requiring any special leak detectors; one's nose is more than adequate for that! :-)

[@rwboa22]

Also the engines on the ULA Vulcan rocket are designed to be recovered and reused, unlike the current Atlas V in which the RD-180 engine is discarded after each use.

[@SkepticalCaveman]

Methane is easy to produce. Farmers here make their own from organic waste.

[@charadremur7354]

@@j.jasonwentworth723 too toxic

[@nahuelalcaide2027]

Call me crazy but even if my rocket wasn't reusable I'd still want the fuel to be as cheep as possible

[@PeterMatthess]

I never get tired of your outro music!

[@themindlesstrader1610]

You're awesome Scott. Thanks for teaching me KSP!

[@DrZond]

There is a very important reason for using methane that wasn't mentioned. That is storage temperature. The fuel & oxidizer must be stored together. So having similar storage temperatures is very important. At one atmosphere, the boiling point of oxygen is -297º f. For hydrogen it's -473ºf. For RP1 it's rated between 350º & 525º f. For methane the boiling point is much closer to oxygen at -257ºf. only a 40º difference. For Hydrogen, the other cryogenic, the difference is 176ºf For RP1, a room temperature fuel, the temperature difference is at least 647º What this means is that methane and oxygen tanks can be next to each other (or within each other) with very little insulation. This is a huge advantage in saving weight. There are other disadvantage of H2 & RP1. In terms of RP1 the coking or residue problem was mentioned. For hydrogen there is what Musk called the "pain in the ass factor" meaning hydrogen's ability to penetrate the smallest cracks, hydrogen enbrittlement & other handling problems. Plus methane is currently much cheaper than hydrogen.

[@HuntingTarg]

Johnny Robinson Yes, the fact that Hydrogen is about the next best fluid to Helium is a perniciously difficult, often painstakingly frustrating problem to deal with.

[@janeymers7154]

I would take this comment seriously, because it contains solid arguments and facts. But sadly stoneage units are being used.

[@DrZond]

Yes the scientific community uses metric, but this video is for science fans who, in America, have a more direct understanding of English units. All the signs on the highway say miles per hour, not meters per second. The ovens are in Fahrenheit so they can grasp those temperatures more directly.

[@HuntingTarg]

I do not recall where the 32 and 212 came from (I think it was calibrated to the melting and boiling points of Mercury, but WTH IDK) - but Gabriel Farenheit had a practical reason for putting the first three prime numbers in his temperature scale multiple times: he hated working with fractions. So the disdain for the Imperial system has a glaring drawback.

[@tsamuel6224]

Jan Eymers - Go back to wherever you got hung up on metric. Or be patient and wait 50 years or so. It'll come. I for one, reflexively hit the gas when I see a metric speed sign. Americans really aren't familiar with how many metric miles will fit in the back of a Ford F-150, or whatever ;D

[@Micklemoose]

Aww, I was looking forward to Scott saying mee-thane

[@claxvii177th6]

Scott, you have a sharp and subtle sense of humor that kills.

[@captaingreen4367]

I have been wanting to know the answer to this question for a long time, thanks Scott Manley!

[@jerry3790]

[Insert methane fart joke here]

[@jackielinde7568]

Stick a tube up my butt, because I'm going to power Musk's SpaceX!

[@smartroadbiker]

Don't we fart hydrogen?

[@pluto8404]

Jerry Rupprecht hahahahahaha😂 lol. Thats a good one.

[@WG55]

Your joke stinks. 😣

[@keco185]

Now cows can finally “jump” over the moon

[@DavidFMayerPhD]

Methane gives only a modest improvement of performance over kerosene because of the need for much more liquid oxygen. However, even a modest improvement is very important because of the exponential character of the rocket equation.

[@brabanthallen]

It also makes much more sense if the goal is a Mars mission due to the exponential mass/thrust aspect of transporting return trip fuel. Manufacturing propellant on Mars is forward thinking, a paradigm shift. If the idea is to colonize another planet, self-sufficiency is a must, and producing propellant on Mars is a must.

[@DavidFMayerPhD]

@@brabanthallen I agree that in-situ production of propellant combination on Mars would be a MAJOR improvement in any scheme for regular interplanetary travel. There are plenty of precursors for the propellants: water and carbon dioxide. The most difficult matter is providing the VAST amount of energy needed to produce the fuel. A kilogram of methane releases about 55 megajoules upon combustion. Hence, at a bare minimum (assuming 100% efficiency) it would take 55 megajoules to make a kilogram. To produce 100 tonnes, would require 100,000 times 55 megajoules = 55 time 10^11 joules. Assume that you wish to fuel ONE such rocket per month (30 days). There are 86400 * 30 = 2,592,000 seconds in 30 days. The average power needed over 30 days to produce the 100 tonnes of fuel would be 2.12 megawatts. Realistically, 100% efficiency is impossible, so let's increase power to 5 megawatts. That is a large amount of AVERAGE power for a plant on Mars to produce. If a nuclear plant, a huge area would be needed as a radiative heat sink. If Photo-Voltaic, it would require a large array. With solar intensity of only 500 watts per square meter, assuming 20% efficiency, then only 100 watts per meter would be produced under optimal conditions. After consideration of load factor due to daylight/darkness, etc, the required area would be circa 60,000 square meters, or circa 250 meters on a side assuming no gaps. That is a HUGE array. It would need to be washed and squeegeed daily to keep dust down, which ups the water requirement, perhaps to 10 tonnes per day. And so on. You can see that this is a HUGE undertaking, although still better than schlepping fuel all the way from Earth for one return flight per month.

[@RawandCookedVegan]

Thanks for your down to earth delivery and explanation. And a thousand thank you's for sparing us, "hit the like button and subscribe." It shows that you're simply doing this out of generosity and an interest in science.

[@1320crusier]

Heh kind of goes along with what I've thought about a lot of engineering: The best engineers can simply designs while preserving performance. Thanks for mentioning the production of methane. I was actually thinking of that when you talked about how simple the molecule was

[@jonathanwernke5449]

Thank you for your stuff!

[@incription]

first, btw :)

[@jeffvader811]

8:52 I think Scott would fit right in at Blue Origin.

[@Fred_the_1996]

LOL

[@robmuzz]

I love geeking out with Scott, even if it's only for 10 mins or so .

[@TheBlackstarrt]

Welcome to Murica, happy to have ya.

[@dcy665]

Scott, do you have a video on how rocket fuel is manufactured, shipped and stored at a launch site? The only reference I have is Footfall(1985) by Larry Niven and Jerry Pournelle, it wasn't very specific leaving me with the interesting concept but no knowledge.

[@SemenHasFallen]

dcy665 good idea I would like to know more

[@matekochkoch]

Really depends on the kind of fuel.

[@LolUGotBusted]

Ignition! By John D. Clark is an excellent book on the history of rocket fuels. Hank Green uses it as a reference in scishow's 'Most dangerous chemicals in the world' Check that out as well.

[@Backyardaerospace69]

When you start talking about the history of RP-1, * Revert to ignition (the book)*

[@oldbatwit5102]

One of the few science explainers that doesn't leave my tiny mind spinning.

[@gregedwards1087]

I don't understand everything you say but I do understand more than I did before watching, cheers. 😊😊

[@EtzEchad]

It will be nice to see BO get something to fly (other than their toy.) There has been a very high hype to reality ratio out of them for the last few years.

[@dotnet97]

At least the engine isn't all hype, considering that they have footage of test firing.

[@EtzEchad]

Himanshu Goel True. It’s a long way from test firing to flight, but they have some real hardware.

[@webchimp]

It would be ironic if the first thing BO gets into space is someone else's rocket.

[@samuelbazinet7181]

@@webchimp Although somewhat ironic, it's very good publicity for them, and there is nothing wrong with more publicity.

[@nathanaelvetters2684]

@@webchimp how is that ironic? Thousands of companies get their hardware launched into space as part of someone else's rocket or satellite. Also, they've already gone to "space" with their own rocket, technically.

[@Michiellovietsj]

At 3:10 it is 12 carbon and 26 hydrogen

[@scottmanley]

Yep, but generally you model RP-1 as Dodecene and assume an average of one double bond.

[@Michiellovietsj]

Then you show the wrong model of the molecule. At 3:21 you also show a lot of different alkanes A small problem with a double bonds is that it can polymerize when it comes in contact with a initiator. Most plastics are polyethylene (PE) and or polypropylene (PP). In the detail specification some maximums are mentioned. For aromatics max 5 vol% and for olefils (alkenes) max 2 vol% ps. I do not want to criticize you, but as a chemist I see these kinds of mistakes very quickly

[@redbandet]

@@Michiellovietsj How can he show the wrong molecule when he sais it is a mixture of many molecules (including dodecane) aromatics would greatly decrease the average H to C ratio and make his comment valid

[@Michiellovietsj]

@@redbandet he said dodecEne. It implies a double bond and that is not shown. If you mean in the movie then it is still 26 instead of 24 hydrogen atoms

[@bok..]

I dont think the specifics really matter in this case. The average person won't remember the specifics, and if you are interested you will look it up.

[@Shogoeu]

Simplicity is great!

[@T25de]

Unsubscribe By KZbin I just looked down and realized I had options to sub and bell... Been a sub since 2011 Scott! Love your videos, thanks!

[@quantumac]

Meth-ane, not Me-thane? Scott must be assimilating. Soon he'll be saying "y'all"…

[@MrGeforcerFX]

i totally forgot until he mentioned it that we say methane different in America.

[@quantum7401]

Meth- is the prefix used to signify a single carbon, and isn't Me- thane, but rather Meth- ane. So, would Propane be Pr- opane or Prop-ane?

[@jackryan2612]

@@quantum7401 yeah i realise meth-ane is the correct pronunciation, but me-thane still just sounds right

[@toddkes5890]

@@quantum7401 Would the opposite of Propane be conpane? ;)

[@InventorZahran]

@@quantum7401 I used to think it was called "pro-pain", because it would give you profuse pain if you accidentally drank it...

[@JoshKaufmanstuff]

@ 05:50 I'm having trouble figuring out Scott's final takeaway of methane efficiency here . . ? "20% vs. 50% advantage" it seems he is comparing RP-1 + LOX VS. Methane + LOX? Is the Methane system less efficient overall? And "Hydrogen is even worse"? Hydrogen has the best ISP of all, right? Somebody that understands, can you please help me out? Thanks! 👍

[@tommieronen7424]

I was thinking about the same thing. Should he calculate the overall efficiency again now when the density is lower but there is also less mass to accelerate?

[@scottmanley]

I was just talking about the density. The specific impulse advantage is about 5%

[@JoshKaufmanstuff]

@@scottmanley Thanks Scott! So your saying that RP-1 vs Methane is at a 50% density disadvantage, however, factoring in the LOX it's only ~ -20% average. But factor in the +5% ISP and the total performance breaks even? Maybe a little worse than RP-1? (But advantages of cooler burn & simpler plumbing make it a boon for reliability & reusability?)

[@sscubing7146]

Density has nothing to do with ISP RP1 and LOX is denser than METHALOX with 20% advantage and methane has higher ISP than RP1 by 5% advantage. Different people chose different fuels according to what feature is more important for them.

[@PaulDebaecker]

Interesting video! It would be also interesting to have a follow up discussing the advantages not wrt RP1 but to hydrogen.

[@professoreggplant9985]

I would love to hear more detailed comparisons to include price point, consumption quantity ie mass, processing & storage, and maintenance & safety related costs. Some of this you grazed over but if you retouch the subject then I'd certainly have interest. Might have to check into the supply and demand side to see if this could lead to investment possibilities;)

[@stinkypantiesss6009]

What happened with KSP? Are u streaming anymore?

[@scottmanley]

Ever tuesday night.

[@HuntingTarg]

Yay, but bugger - I have a recurring engagement Tuesday nights. Oh well, stream safe, Scotty! 😉

[@Haos666]

There is one important bonus of having both propellants cryogenic: you can store them for longer out there in space. RP-1 will not last long unless you can keep it warm (and liquid).

[@Ruiluth]

Actually, it's more difficult to keep things cool than warm in space. The main reason they don't use liquid hydrogen for long-range craft is because keeping it cold just isn't doable.

[@ASAVSP]

I know how to play KSP because of you. Thank you Scott, amazing video.

[@RTD1947]

Excellent explanation!!

[@moosemaimer]

New news: possible new Kuiper Belt planetoid discovered, at 2.5x Pluto's orbit!

[@scottmanley]

Only 300km, not even a dwarf planet. But it's orbit is aligned with other outer solar system bodies.

[@ChrisSchaff]

Sources plz

[@afish976]

Object's designation is 2015 TG387

[@scottmanley]

Which shows that they've been trying to determine the orbit for 3 years

[@jerry3790]

Scott Manley Still an interesting thing to talk about.

[@jackielinde7568]

(At hearing Scott pronounce Methane and why): One of us! One of us! One of us!

[@dazuk1969]

I really like Scott....he is responsible for my newfound interest in space...but this one of those vids where I just feel out of my depth...but I do learn something every viewing...Peace.

[@joemesserman4278]

love your videos thanks a lot!

[@wuznab5109]

Harvest the cow farts to get to space. BEST.... IDEA..... EVER!!!!!

[@vaga4239]

India will jump ahead of the US lol

[@deamonic456820]

The methane from cows comes from their burps, not their farts ;)

[@fedaykinwolf]

to the MOOn

[@verttikoo2052]

WuzNab And send the cows first 😆

[@legolegs87]

I still do not get why the methane was not widely used before. The reasoning of "methane is too expensive to buy" seems to me even more ridiculous that "rocket scientist were trying to avoid fart-jokes".

[@arsarma1808]

legolegs cost per pound of payload is very high already. I think cost is very much a concern.

[@legolegs87]

@@arsarma1808 is H2cheap? UDMH?

[@redbandet]

Hi Scott, always love your videos and use them as my main space news source. Just wondering what do you use as your source for news like this I can never find any of the interesting stuff like this (new engine suppliers) through news sites via google

[@andrewwebb7238]

Hi Scott Manley, could you do a video on how Specific Impulse is calculated? You mentioned the mass and temperature of the exhaust being factors in increasing/decreasing the Specific Impulse, but what else effects this and to what extent does having a lighter exhaust or higher temperature have? Thank you

[@R_C420]

It's not US-thane. It's not YOUthane. It's not WE-thane. It's ME-THANE. I literally only opened the vid to hear you say it, but the rest was pretty interesting also.

[@seisette]

You shoud do TED Talks or something similar.

[@fermibubbles9375]

great video scott! the methane maneuver was brilliant! Methane can be found on Mars, Jupiter, Saturn, and Titan. In the case of Uranus and Neptune, methane actually gives the planets their distinct blue-green coloring!

[@thecanadiankiwibirb4512]

Nice Educational but simple

[@Boomchacle]

they must have been browsing too much Children of a dead earth forums.

[@Krusesensei]

9:00 "a new company" 😂 Just a bit older than space X ;)

[@jamestheotherone742]

That has yet to launch anything into orbit.

[@Odd_Taxi_epi04]

I don't know any company named space X. But that name sounds very similar to SpaceX...

[@jamest.5001]

How about a video on the pattern in the flame from the engine? I think it looks soo cool, it's what got me interested, but I never learned what it is or the cause! Thanks,

[@michaelwoodhams7866]

Here is a somewhat off-topic question: What's with the throttlability of the New Shepard's BE3 engine? New Shepard's booster lands in hover with just one engine. So that one engine is able to give over 1g acceleration to booster+full propellant load+capsule at lift-off, and yet throttle down to less than 1g acceleration on booster+very little propellant at landing. By contrast Falcon 9 has to do a 'suicide burn' landing because at minimum thrust they still have over 1g acceleration on a nearly empty booster stage. (I think Scott has a video on this.) This is despite the fact that they have a factor of 9 advantage over New Shepard, because they can light just one of 9 engines, where New Shepard has to light 100% of its (one) engine. One way of doing this is to have a very large dry mass for your booster, so the full to empty mass ratio is not large. I hope this isn't the case.

[@abcdefgh-db1to]

Do you think there's a chance we see nuclear engines (NERVA type) in the relatively near future ?

[@RS-ls7mm]

Zero probability that the US/Europe will use them given the near hysterics that the greens make over the microscopic particles of radioactive material in the current spacecraft. Russians and Chinese don't care what the greens think so they will probably do it. Maybe if we mine/refine the radioactive material in space.

[@5Andysalive]

So... why haven't they? It's not like the idea is new.

[@RS-ls7mm]

I suspect they aren't really that good compared to the electric propulsion systems. NERVA seems like a niche (heavy/fast/crude).

[@abcdefgh-db1to]

@@RS-ls7mm they are much much better than ion propulsion on a thrust level and they have twice the ISP of chemical propulsion they can replace second and third stages unlike ion propulsion. Yes they are a bit heavier but they need much less fuel so it has a clear advantage over chemical

[@totalermist]

I doubt it. This is not a "green hysterics" type of thing, but simply a matter of economics and rationality. The thrust-to-weight ratio of a NERVA type rocket is nowhere near that of chemical propulsion and a NERVA type engine would essentially be payload for a chemical rocket to get it into space. A BFR-style approach is much more economical - just use the same rocket to launch into LEO and for BEO targets utilising in-orbit refuelling. The only advantage of NTR is the lower fuel weight, but that kind of loses importance as you look at cheaper alternatives such as in-orbit fuel depots and BFR/SLS super heavy lift capabilities arrive. The BFS tanker variant and the Raptor and BE-4 engines might be the single most important developments in that regard. While NTR is a one-way only solution (e.g. after fuel depletion you can basically discard the engines), methane-powered engines can use fuel from in-situ production on Mars and Saturn's moon Titan.

[@christiannorf1680]

I was quite surprised that Blue Origin is planning to use propylene rather than ethylene, which has very similar properties according to the table you showed. Because propylene is waaaaaaaay more expensive than ethylene. Does anyone know why they prefer it? The only reason I could imagine from the top of my head is propylene being safer as it does not tend to polymerize as easily, which is exothermic and can lead to runaway reactions aka unscheduled rapid disassembly. While again that should not be a problem at cryogenic temperatures and the chemical industry is using ethylene in quantities of hundreds of millions of metric tons per year (literally).

[@Haos666]

BO is going for Methalox. Propylene is being considered by Vector Space Systems instead.

[@kodiak2fitty]

@Christian Norf Blue Origin is not using propylene; They are using methane. Vector is using propylene. I've seen evidence that both propylene and ethylene are viable options but nothing to indicate why Vector chose propylene.

[@Norman92151]

Love the rocket science information.

[@MrBrukmann]

LOL I loved the way you pronounced meeethane! It sounded weird hearing you say it the American way!

[@EduardVasile5]

Well,i already know the answer, but it doesn't hurt to double check

[@TommoCarroll]

Plus you get to watch Scotty boy! What's not to like!?

[@pmm1767]

@@TommoCarroll hello there science Justin Y I watch your vids too lmao

[@TommoCarroll]

praanav m haha! I wish I was that prolific in the comments! I was literally moments ago seeing what sub count that dude was up to - 600k - unbelievable!

[@w0ttheh3ll]

another advantage: helium is a finite fossil resource, so using less of it is great.

[@kodiak2fitty]

Wow! What former life (now a fossil) produced helium? Delete "fossil" from your statement and it would be correct :)

[@stephenallen4635]

it's just a finite resource, just like methane

[@ljfinger]

Helium is actually still being produced in the Earth (not by dead lifeforms, of course) by nuclear decay.

[@leerman22]

Just get a bunch of uranium and other natural alpha emitters together in a giant tank.

[@kodiak2fitty]

See physics.stackexchange.com/questions/109985/is-it-possible-to-manufacture-helium for why manufacturing new helium is a non-starter. If you want a billion-dollar party balloon, sure, go ahead. Otherwise, consider it essentially a finite resource on planet Earth.

[@LaserFur]

I still love how you earlier called RP-1 "creative" in terms of forming stuff and plug up the engine.

[@Paul-gz5dp]

Nice shock diamonds in the video at the beginning!

[@ComradePhoenix]

You could just have the crew eat nothing but Taco Bell, and you'd never run out of fuel.

[@OldF1000]

But the crew would kill each other off

[@Tadesan]

There's more hydrogen in a gallon of gasoline than there is in a gallon of liquid hydrogen!

[@brainmind4070]

Tadesan How is that even possible? Seeing as one atom takes up a certain volume, A gallon of gasoline has a lot of carbon in there taking up space. I think you've got some phases mixed up or something.

[@benjaminowen6181]

I think he might be talking about the gaseous hydrogen, with the atoms spaced out and less dense

[@robrocksea]

Hydrogen has more potential energy by Mass and burns Hotter. Gasoline will burn colder so it has less energy. The extra performance far offsets the added weight. So the mass of a larger fuel tank will be lower per volume. The the added surface area mass grows slower than the volume it can contain.

[@robrocksea]

Different Atoms and Molecules do no take up the same space. that is it's Density. If you fill the same size buckets and fill one with Water and the other with Lead which weighs more?

[@brainmind4070]

Robert Losey Dude, what are you talking about? Also, the lead is denser mostly because of the amount of protons and neutrons in its nucleus. Of course, density doesn't scale linearly with atomic mass, though, since the size of the electron cloud also factors in.

[@dotsmassacre]

Which I would think is a little more complex as a system but at the same time, when we look at compression density as a property of thrust ejection... we're looking for all of the pressure we can get...

[@cowboybob7093]

1:32 Titan I also - AerojetGeneral used the same basic engine for their hypergolic setup for Titan II and they were even developing a hydrolox version of the kit for a while, to compete with the J-2.

[@TonboIV]

1:42 Not quite. RP-1 is not made from ordinary jet fuel. It's refined from crude oil, but it has a tighter standard than more common kerosene fuels. Refineries have to be pickier about which crudes they use when making RP-1, and they also have to use a narrower "cut" during distillation, so that less of that crude actually becomes RP-1 and more of it is made into other products. RP-1 ends up having a more consistent composition, but it's also more expensive to produce, and less is available, compared to other fuels.

[@nathansmith3608]

in broad terms, it's the same as refining kerosene, but "more" refining is done to meet the tighter spec. That's consistent w/ what I got from the video, so you're "not quite" correcting anything

[@TonboIV]

@@nathansmith3608 RP-1 is always kerosene in the sense that it's a selective grade of kerosene. It's not really refined 'more', so much as more selectively. To me, the words "made from" suggest that the oil is first refined into kerosene, and then some of the keresene is made into RP-1.

[@jonharson]

I had always assumed that RP-1 was just kerosene with a low guaranteed sulfur contain, but as it turns out you are right, the production process is a lot more complicated as great care is also taken to reduce the number of alkanes which can produce complex carbon structure/sooth. The more you know...

[@paulsengupta971]

So you can't just use diesel then?

[@lloydevans2900]

With RP-1 refinement, branched alkanes are not the problem - they are in fact a benefit, since a high degree of chain branching confers additional stability compared to straight chain alkanes. The same is true for gasoline for spark-ignited piston engines - the ideal fuel is iso-octane, aka 2,2,4-trimethylpentane. The least suitable fuel is straight chain heptane, which actually represents the zero point on the octane rating. The molecules in crude oil which cause the biggest problems for rockets come in three main classes: Alkenes (aka olefins), aromatics (such as benzene or alkylbenzenes) and any hydrocarbon containing hetero-atoms, usually sulfur or nitrogen. These can all decompose in regenerative cooling passages (around the combustion chamber or nozzle) to deposit coke and a plethora of polymeric gunk. Alkenes and aromatics can both be dealt with by hydrogenation, which converts them to alkanes and cycloalkanes respectively, either of which are acceptable components of RP-1. The sulfur or nitrogen containing hydrocarbons can be dealt with by hydrodesulfurization or hydrodenitrogenation, which remove the sulfur as hydrogen sulfide and the nitrogen as ammonia.

[@JustSomeCanuck]

2:08 Yeah, just after you've watched that is when you need to water down the ethanol and drink it...

[@myyklmax]

The preburners are used to convert the liquid fuels into a gas for clean burning during ignition. Plus liquid methane can also be used as a engine coolant.

[@biropa04]

Thats great for Vector to use propylene. Propyne (aka methylacetylene) as rocket fuel would burn even hotter, but there are problems with it recombining in the tank to create other molecules such as Teflon. Methane is also more easily manufactured.

[@neurofiedyamato8763]

5 minutes and already 23 comments... damn wth, do people just sit on the PC refreshing page for the next Scott Manley video?

[@jrtc53]

Neurofied Yamato then how did you see the vid five minutes in

[@newsgetsold]

If the 750,000 subscribers check their KZbin account once per day that's an average of 520 per minute.

[@robrocksea]

Auto-alert on cell phones, and they don't watch or listen they just comment, for the 5-sec fame

[@ahaveland]

I can only conclude that the average subscriber age is somewhere around 10, judging by the amount of fart and cow "jokes" demonstrating an extreme lack of knowledge on the subject. 1. A typical fart is composed of about 59 percent nitrogen, 21 percent hydrogen, 9 percent carbon dioxide, 7 percent methane and 4 percent oxygen. 2. Methane has no smell. 3. About one percent of a fart contains hydrogen sulfide gas and sulfur-containing mercaptans, and it is these that are responsible for the characteristic aroma. 4. Cows mainly burp methane.

[@bluemountain4181]

Yeah I guess all these people saying that farts are methane are just talking out of their ass

[@adamkendall997]

Hey! I resemble that comment. I'm 39 and I appreciate a good fart joke.

[@fred6319]

the characteristic aroma. LOL

[@oakwhelie]

I like farts

[@maracachucho8701]

I highly doubt there are many children under 10 who associate farts with methane or even know what it is.

[@AndreHauger]

Scott, you plan to do a video on the Norwegian Nammo Nucleus launch/engine?

[@oktaykurttepe8376]

Hocam güzel anlatıyorsunuz , ağzınıza sağlık.

[@MachOverspeedsPlace]

4th generation Texas oil & gas business here. America's lower 48 states alone (not counting Alaska or the Coastal Waters) are sitting on top of enough clean-burning methane (aka natural gas) to power the entire nation for better than 200 years. And over 3/4 of that vast mineral wealth is held by literally millions of workaday citizens (in the form of mineral rights) who don't even know it. But they will. And sooner, rather than later. Because the US is on track to become the world's top energy exporting nation by the early 2020's. And all those mineral rights = fat royalty checks. And cheap rocket fuel too... Just saying. MachOverspeed

[@phiksit]

And those HUGE gulf coast LNG exporters are paying next to nothing in taxes. How does exporting our energy resources help with our energy independence. Sounds like straight up greed to me.

[@iflycentral]

Don't worry. We know what you mean when you say ME-thane. :D

[@HuntingTarg]

I Fly Central Me Thane, You Kerbal!

[@MonsterSound]

Love your videos. Just a small critique about the ending music volume. It is too loud. Might just be me but, there ya go.

[@jeffmcclure888]

At 6:15 you mention that hydrogen is "really bad" with regard to the weight ratio when you include the oxidizer. Can you elaborate? Do you have a video that compares hydrogen to other fuels?

[@supejc]

NOTIFICATION SQUAD ASSEMBLE

[@TommoCarroll]

I'm here! Am I late? Oh no...I have let the squad down 😭

[@TommoCarroll]

haha, good effort anyway Terry mate!

[@djprojectus]

Big Farting Rocket BFR !!! Ohh,i get it now!😉

[@aasquared8191]

fucking*

[@aasquared8191]

pun was bad anyways

[@tsamuel6224]

Oh, and I thought it was Big Friendly Rocket!!!

[@aasquared8191]

@@tsamuel6224 yep dude my bad it definetly was

[@samevans8922]

HAHAHAHAHAGAHAHAHGAHGAGAAHAHHAAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHHAHAHAHAHAGAHAHAHGAHGAGAAHAHHAAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHA HAHAHAHAHAGAHAHAHGAHGAGAAHAHHAAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHHAHAHAHAHAGAHAHAHGAHGAGAAHAHHAAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHA

[@j.jasonwentworth723]

Scott, I was born here in the U.S. (as was my father), and he pronounced it "MEE-thane" (as did I, for many years). His father was from the Cayman Islands, though, which may explain that (my grandfather also pronounced the letter "H" as "hee," and the letter "W" as "wee," as he was taught in school there). Regarding methane--however one pronounces it :-) --as a rocket fuel: NASA for a time funded methalox rocket development (during the George W. Bush Administrations) for use in the original Orion lunar/Mars mission architecture. By using a methalox Service Module engine, they intended to build-in a capability to eventually refuel from short-period comets and from the asteroids that are actually extinct comets (but still rich in water, ammonia, carbon dioxide, and methane ices, insulated by those "asteroids'" dusty outer crusts. The water could be electrolyzed to obtain oxygen, and the methane ice could be heated to generate liquid methane (the hydrogen from the water could also be reacted with the carbon dioxide, via the Sabatier process, to make LOX and liquid methane).

[@davidh6300]

Scotty you are a legend

[@TrumpCardMAGA]

Also next generation rocketeers are using meth.

[@hamidhamidi3134]

The Chinese did it.

[@johntheux9238]

How good is the thrust per nozzle area ratio of the raptor engine compared to the merlin, the be-4 and others liquid/solid engines? (for rockets with higher sectional density)

[@JoshKaufmanstuff]

@ 05:16 does this mean that the BFR won't need the problematic C.O.P.Vs?

[@NeoFlorian1]

whoa theres no views, no likes, no dislikes and no comments :D

[@TheRagingStorm98]

When your in the early camp

[@CombraStudios]

is this the first comment? probably yes. Congratulations. You have been chosen by the youtube algorithm the privilege to say "first"

[@isaiahdobesh5109]

TheGamingCreeper295 and you had to go and ruin it. Though someone else would’ve done it anyways

[@801russc]

I say stick to your roots Scott, Methane "Meethane" "Mehthane" I know what you mean.

[@joe2mercs]

Scott great video as always. Super cooled RP1 as used in the SpaceX F9 rocket has a density closer to 1Kg/l. The ISP of ‘closed cycle’ rocket engines for either RP1 or Methane are very similar. Correct me if I am wrong here but the ISP pertains just to the fuel consumed and not the fuel/oxygen mix (propellant). I ask this because 8 understand that the ratio of fuel to LOX is 1 to 2.6 for RP1 but 1 to 3.8 for methane. Methane is less dense than RP1 but a methane rocket’s dry mass must be greater to provide the larger tanks to contain the fuel. Furthermore such a methane rocket must carry 33% more LOX, which again means larger tanks. My own calculations suggest that a methane rocket will have to be at least 11% physically larger than its RP1 equivalent to deliver the same maximum payload to orbit. Maybe it would be a good challenge to use KSP to design rockets with a given 50 ton payload to LEO based on RP1, Methane and hydrogen and then compare the dry mass of these three cases. The Saturn V with crude gas generator ‘open’ engine’s was about 5% dry mass and delivered about 4% take off mass to orbit. My guess is that BFR will struggle to get below 5% dry mass and 2% payload, albeit fully reusable.

[@chriskerwin3904]

Read about fuel mass ratios. It's a topic that explains exactly what you're talking about.

[@joe2mercs]

chris kerwin thanks for the pointer. ISP I now know pertains to propellant (fuel + oxidiser). In the process of reading more on this I found out that the Space Shuttle system was 20% dry mass and 5% payload (Shuttle orbiter + payload contents) to LEO.

[@donsparrow4786]

Interesting stuff! Question Scott: how does the discovery of 2015 TG387 impact the search for Planet 9?