SpaceX’s Explosive Engine Problem
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- Опубліковано 23 лис 2021
- Join me as I explain SpaceX's explosive engine problem, and then join 8 million other learners by giving Brilliant a try today at brilliant.org/primalspace
With Starship almost ready to do its first ever orbital test flight, it will rely on help from the raptor vacuum engine. But testing vacuum engines is a little bit more difficult than you’d think. This video looks at how these engines were tested in the past and how SpaceX has managed to get around the main problem.
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» Infinite Perspective - Kevin MacLeod
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Credits:
Written and edited by Ewan Cunningham ( / ewan_cee )
Narrated by: Beau Stucki
#spacex #starship #raptorengine - Наука та технологія
Non-vacuum optimised engines don't 'become less efficient' the higher altitude they get, they actually get more efficient, it's just that vacuum optimised engines become disproportionately more efficient.
@@alexv3357 What he means is that an SL optimised engine will always be less efficient than the same engine vac-optimised at the same altitude. However, if you take a single engine, SL or vac optimised, and chart its Isp as it ascends through the atmosphere, its Isp will always increase. A SL engine, like a vac engine, also has better Isp in vacuum due to the drop in pressure, it's just not as pronounced as it would be with a vac engine
@@alexv3357 No, Adam is correct. Although a sea level engine is optimally expanded at sea level, it still gains efficiency as it becomes over-expanded.
This is because the reduction in pressure slowing the exhaust increases efficiency more than enough to offset the losses from the less optimal expansion.
A vacuum engine gets the increase from pressure reduction *without* the losses from less optimal expansion, hence getting a bigger increase.
Raptor sea level goes from 330s at sea level to 350s in vacuum, which is still an increase, but not as much as the Raptor vacuum which gets 380s in vacuum.
@@lazarus2691 Exactly so :)
@@alexv3357 actually the first comment is right, specific impulse increases with altitude pretty much regardless of nozzle design all the way to vaccum. It's just at the vac engines maximum Isp is at a higher altitude.
@@alexv3357 sea level engines still have more ISP at vacuum
There’s also a ring they put around the edge of the nozzle for static fire tests that is removed before flights. You can actually see it in the video you showed
timestamp ? big thanks
@@PresidentialWinner 1:13 look at the edge of the nozzle. You can see a ring going around the edge. Someone got a closeup of one of those rings in boca chica and they say “STATIC FIRE RING. REMOVE BEFORE FLIGHT” on the side of them.
@@MapedMod that’s cool. How do you know that? Do you work for spaceX?
@@MapedMod but how do you know the ring isn’t there for reinforcement? It could be that
@@MapedMod this engine operates in the vacuum where no such air is present.
The spaceshuttles nozzle also curls inward slightly to reduce the likelihood that the flow separates.
My Man is finally back
Ye he only uploads like every 3 or 4 weeks
haha the quality of his content is so good but he only uploads 4 to 5 weeks 😬
1:01 Saturn V isn't the most powerful rocket ever made, this goes to N1
It(the Saturn V) is the most powerful rocket ever successfully flown.
Actually, the N1 didn't get very high off the launch pad. It exploded a few minutes into its flight.
@@glenkeating7333 that was my point. It wasn't successfully flown. However the first stage of the N1 still is the most powerful rocket ever yeeted of the launch pad. Period.
You can look it up.
thx for clarification lol
@@vicentecrestani5812 . Oh, I agree with you.👍
@SFS Cheetah . The SLS has never flown.
Your videos are better than any TV documentary ever made. .. LOVE your work. ... Thank you.
Dude, I absolutely LOVE these videos! Thank you so much!!!
Love your videos and the animation style keep up the hard work!
This man's transitions to advertisements is too clean
Polymatter is smoother with ad transitions tho
Thank you for making these videos. You're a big part of keeping my interest in space. So glad I found your channel at 10k subs.
Did anyone else try to flick the bug in LZ's user image
@@jessefurlan5585 Yeah, I've had some small flies around for a while so I was like, Ugh, not again
i'm more interested in the steam ejector system that can remove the exhaust from tons of liquid combusting every second from a fairly small pressure vessel.
true
yeah how the fuck
I dont think they can do it with engines That use tons of fuel every secund. Properly only smaller engines.
Raptor only uses 650kg/s and That is a bery big engine for vacume.
Great video with fantastic helpful explanatory graphics!
The only problem with Raptor imo is that it doesn’t have the “honk” on shutdown anymore
I miss the sound of those valves closing, it used to sound like a monster from Godzilla.
rlly? that's what used to bother me lol
@@Loading-lg6hs at first it didn’t sound like a healthy noise it should make, but as time went on it grew on me haha
Pinochet
need posters? why you cry here?
why this mad community? what you need here?????
Saturn V isn't the most powerful rocket ever made. It is the most powerful rocket to reach orbit so far however.
The Saturn V is most powerful rocket ever made to not explode within the first minute after launch, or as some may say, the most powerful rocket ever made
@@Ignacio.Romero made: something that has fully been produced. Even if something is bad or does not work, if made it is made.
Best description of Saturn V is the most powerful rocket to achieve it’s mission
@@AlexandreJWKlaus Please, you can't that say something that wasn't designed to blow up, but made the biggest non-nuclear explosion on Earth anyway was "fully made". Stop with the nonsensical technicalities.
The N1 can get the title of being the most powerful rocket ever designed and tested tho
@@Ignacio.Romero yes, what I am pointing out is the Saturn V is the most powerful rocket that accomplished it's mission (rephrasing of what I said before).
This is the type of guy that if someone said "the sun rises in the East" would contradict that and say that only applies if your exactly on the equator... If your not on the equator then your off east by degrees of latitude.
A quibbler.
Excellent explanation of the challenges involved !!!!
Thanks!
So what is the "SpaceX's Raptor Testing Problem" if it can be tested at sea level without any problem?
Clickbait, that’s the problem.
@@reagank.2268 tldr, they take off the nozzle. that's not problem at all.
@@anthonyasp1295 they take the nozzle off for Merlin, not Raptor
agreed. An entire video about a problem that elon stated wasn't a problem in a single tweet :/
I think I’m gunna be able to hear the starship launch from the UK.
I read the title and was worried, after watching the video i feel like this problem Sounds like one of those good problems, one that is pretty much solved. In fact you even mentioned they have an advantage concerning this issue.
Love your videos keep it up
There's a bit of a mistake at 2:22 where you say, "if the pressure is higher than the ambient temperature". I'm sure it was just a slip of the tongue
Excellent video.
Great video 👍🏽
This was so good, were is part 2 :)
Primal Space, the Saturn V wasn't the most powerful rocket ever, that goes to the N1 currently.
The N1 wasn't ever successfully launched. That's like saying the Starship is currently the most powerful rocket in existence...it's not; the Falcon Heavy is until Starship flies.
@@kebha6308 It wasn't successfully launched but it launched 4 times which made it the most powerful rocket ever launched.
@@kebha6308 It was successfully launched, it just didn't complete it's mission. If you light the engines and it leaves the launch pad that's a successful "launch".
I guess SpaceX couldn't (or didn't feel it was necessary) to launch a single 2nd-stage Raptor vacuum engine, mounted on a regular Falcon 9 first-stage booster? If it were possible, then you can directly test the single Raptor engine in the true vacuum of space, thus cheaply re-using a first-stage booster to get the Raptor engine into space. Hopefully the strong Raptor bell nozzle will continue to hold up during further testing.
Putting RVac on a Falcon 2nd stage would require a complete reconfiguration of the fuel tanks, and the thrust would likely be too much. Also, Falcon's stage 0 does not support cryogenic fuel. (Only the oxidizer is cryogenic)
Simply put, the cost would be far greater than the benefit.
Brilliant ly created video...
New video!! I like that
Instead of launching a car to space, they should have sent a vacuum raptor test vehicle.
Just because the Raptor has a higher chamber pressure doesn’t mean its exhaust pressure is higher than sea level ambient. The job of the vacuum nozzle is to reduce exhaust pressure as low as possible, regardless of how high the chamber pressure is.
Yeah this video doesn't make any sense
Yes Elon tweeted that thrust was high enough to prevent flow separation for Rvacs at SL.
ahh... so that's what he meant by "flow separation"
Love primal space
Title sound like "SpaceX has a major problem! oh no!"
The video is like "Nah it's all good homie".
Just bought a poster :)
nice vid
The explanation at the end that Raptor has a higher chamber pressure enabling Vacuum Raptor sea level tests without over-expansion issues doesn't make much sense. If the nozzle is designed to be properly expanded in vacuum, then it is by definition over-expanded at sea level, that is completely independent of the chamber pressure. Ultimately at the nozzle exit plane in a sea level scenario for any vacuum optimized nozzle, there is exactly 1 atmosphere of difference in pressure between the nozzle's optimal design exit ambient pressure and the actual exit ambient pressure. For any given chamber pressure, a vacuum optimized nozzle should be designed to get the exhaust as close to 0 kPa at the exit plane as practical, which just means more expansion for engines with higher chamber pressures.
I get that this was Elon's response to a tweet, but that response doesn't make much physical sense. My guess is that the explanation of higher chamber pressure isn't meant as a direct explanation, but instead is alluding to a more indirect effect. For example, maybe because the chamber pressure is higher, you can get still get a large pressure ratio between the throat and exit while still having a relatively higher outlet pressure. But that would still mean you are leaving performance on the table by not sufficiently expanding your vacuum optimized nozzle (essentially wasting some of the performance gains associated with designing to a higher chamber pressure). I think that is what was meant when he said the engine isn't fully vacuum optimized yet, which is the actual reason they don't have to worry, because they aren't dropping the exit pressure as low as they could be. Maybe that is made more tolerable by having a higher chamber pressure, but you are still needlessly leaving performance on the table, performance you worked hard to get by designing to such a high chamber pressure.
Given the high chamber pressure and therefore extremly high expansion ratio need to get to the same near zero pressure, I think the vacuum raptor might not be as close to zero as other engines simply because it's limited by physical space to fit at the bottom of Starship. this would mean that it could be less susceptible to flow separation simply because the pressure on the inside wall near the exit is higher than on other vaccum engines.
I this part of what you are saying? Or am I totally off?
thanks
We also see a bit of nozzle flex on every second stage engine start up on a Falcon 9
Nice
I love primal space.
If they send an rvac up in a module on a falcon9 they could theoretically test it pretty well. Would be expensive though
Hoo boy. Looks like your title selection was jinxed. Or maybe it jinxed spacex
Primal Space mastered "Art of Thumbnail"
I learned from this video more than a 6 years of KSP missions!
0:51 N1: Hi 👋
By the time Starship goes into standardized production, it won't be called Raptor anymore (Elon commented to thus already). The current Raptor has went through hundreds if not thousands of tweaks over the last few years. You never know, they might even figure out a sea-level/vacuum hybrid that eliminates the need for separate models.
I think the new engine will be a loot further down the road than you think. i think they'll start mass production with Raptor, and then make the switch after. I could be completely wrong tho
The shuttle engines turned out to be the most reliable in between engines ever built and every one of them has been used at least four times the true meaning of reusable
Certainly seems like they could design and adjustable titanium sleeve that could slide down and expand as they got into higher altitudes.
I believe that ULA did that with one of their engines on a Delta rocket or some other one.
This video is really great, it should has more views!
How mouch would cost shipping that poster to Slovak Republic?
If you can just increase the chamber pressure to make the exhaust match atmospheric pressure, surely you could just use that capability in flight to get better exhaust velocity and higher ISP?
What he said in the video is wrong; on horizontal test fires of raptor vac you can see the flow get pushed in by the atmosphere and form shock diamonds. It does not match atmospheric pressure
Did the Saturn V have a RUD? Would be a good preview if the Starship blows up.
No, but the N1 had a few.
This aged well.
hey guys.. hope everyone is well
Come on double saturn!!!!
what people see in the thumbnail : Raptor
what I see : Raptop
2:23 ambient pressure
i guess they should have hired me if they wanted their problems solving quick
RIP Boca Chica village and surrounding nature reserves.
@Vesta 2022 Isn't it? The massive amount of power exiting the vehicle has to go somewhere. And if there's a failure on the launchpad, wouldn't it be a disaster of N1 proportions?
@Vesta 2022 "just" the sound is minimising an enormously disruptive event.
crei que habia visto el cohete , pero no aparece en las noticias entonces no se que vi . jaja
2:20 “If the pressure is higher than the ambient temperature”
huh?
Biggest problem with Raptor is starship isnt allowed to fly yet...
This is the same problem the USSR’s N1 had
Didnt the N1 put off more thrust than the Saturn V?
Yes it did, but it's max payload to leo was smaller.
SpaceX is gonna do some building for a non/air pressure lock for the engines. No way will spaceX will ignore the engine problem, so it’s possible for the testing.
main problem.. we still use round nozzles, think we have done most we can with this old rocket engine design- yeah, u can push it- but that just makes it even easyer to demage.
Can you think of a better nozzle design for chemical engines?
That's because "round" is the best shape. You have the least amount of area per volume and it is the strongest when it comes to stress. There is no need to go to any other shape.
Ill give it away, the earospike gets me hard, and i think it still can be made lighter and faster..
@@mathewcherrystone9479 Look up the Toroidal aerospike..
@@OGPatriot03 well the nozzles on these are still round since only the lower bell part is replaced by the aerospike while the burn chamber is still that of an regular rocket engine.
Q: Does "...run the engine at a much-higher chamber pressure" equate to saying they "overdo it" on the ground as an analog for the actual run? I re-watched it a couple times, and bluntly, I don't think I get it!
I think Raptor just has much higher chamber pressure than engines normally do. I wonder if the vacuum engine could then be even more efficient with bigger bell but it's just not feasible to make it so big.
Qwarzz Yes they can expand the nozzle of the raptor vacuum but they have no space for it in the starship. Also the nozzle have regenerative cooling and making it bigger becomes a problem since you now have to cool a much larger surface area.
Think about the explosion when super heavy has a launch accident.
Sigma company rule 101: don't say you are promoting yourself, say that you are sponsoring yourself
The vacuum engine still experiences overexpansion at sea level
Just a short fact check. the soviet N-1 rocket was the most powerful rocket ever built. also a 1960's moon rocket but wrong side of the pacific
I visited the spaceX launch site
la beast music ftw
It went boom lol
yeeeeaaaaah I guess we'll have to wait and see what happens next now
33 points of failure and a bad design. Smart!
By that logic, the 27 engines on falcon heavy are all points of failures ?
And in what way is starship a bad design?, also tell what you’d consider a “good design” for a 5000 Ton fully reusable rocket.
this aged well
Booster 7 just blew up
0:52 ever successfully flown* , not made
The N1 actually had more thrust on its first stage
So basically with Raptor there is no Explosive Engine problem :/ just like Elon said in a single tweet.
Fun fact: the Raptor Vacuum is a pretty good sustainer engine, just like the RS25 and Vulcain engine. Might be a good contender for the main engine for the Vulcan rocket…
Don’t aim for success if you want it; just do what you love and believe in absolutely, and it will come naturally.
🌹Good Morning🌹
*यदि आप सफलता चाहते हैं तो केवल बिना लक्ष्य के वही कीजिए जो आपको अच्छा लगता है और जिसमें आपको पूर्ण विश्वास है, सफलता आपको खुद-बखुद मिल जायेगी ।*
🌹 सुप्रभात🌹o
Temperature and pressure.
So the point is not that the vacuum engines explode, it's just that they have not been tested in a vacuum?
Why are they worried about air getting into the exhaust funnel in space
That sponsor segway
Saturn 5 is *not* the most powerful rocket ever made as described in the context to liftoff thrust.
It's the most powerful US rocket so far in terms of thrust at lift-off.
It's the most powerful rocket overall in terms of payload to LEO.
But Saturn 5 had less trust and gross mass at liftoff than both N1 and Energia, if I remember and Wikipeia correctly.
The Energia had less thrust than rhe Saturn V, but otherwise correct.
@@mathewcherrystone9479 You are correct, according to Wikipedia, now that I do better math in my head, it is actually about 1% less. I stand corrected :)
But nucler rocket more powerful. Then chemical engine.
It's not. The power output of a nuclear thermal engine is lower than the power output of most chemical engines.
That's why we need a facility on the moon . Or while we test them on the iss - pusch it to the moon . ( joke , little)
"loose efficiency no matter how they're shaped".... Aerospike?
The brightest minds on the planet ? SpaceX just fired loads of their top guys for pure incompetence. Brightest minds INDEED !
So apparently the head of Raptor development was recently let go
Retired after several decades. Founding employee of SpaceX, already successful engine designer.
After designing the Merlin, Kestrel, Draco and Superdraco engines (with over 1000 successful mission firings), he designed the Raptor 1, Raptor 2 and Raptor Vacuum engines. No one works forever. Hardly "let go".
@@gasdive I'm not talking about Tom Mueller though.
@@dsdy1205 oh, my mistake.
Please, tell me they are working on 1 or 2 more starships, if this fails. I’m not getting any younger.
They are
Actually all rocket engines have better efficiency at high altitude even sea level ones
Sooooooooo, what's the explosive engine problem?
Hi
4:13 OHIO💀
OHIO
Sorry, but nobody's going to be colonising mars for so many reasons you've entirely ignored.
4:14 "at a nasa facility in ohio"
only in ohio fr fr no cap
Second
well it exploded
That it did :/