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- เผยแพร่เมื่อ 4 พ.ค. 2023
- In 1926, Robert Goddard launched Nell - the very first (successful) liquid fuel rocket. But Nell wasn't built like other modern rockets, including a notable lack of casing and an exhaust nozzle suspended above the propellant tanks.
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Sources:
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www.aps.org/publications/apsn...
apps.dtic.mil/sti/pdfs/ADA328...
arc.aiaa.org/doi/abs/10.2514/...
www.thisdayinaviation.com/16-...
www.smithsonianmag.com/air-sp...
www.smithsonianmag.com/air-sp...
www.nature.com/articles/105809a0
www.braeunig.us/space/propel.htm
Interview with Alfredo Morales, aerospace engineer, Space Generation Advisory Council El Salvador
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www.nasa.gov/content/liquid-o...
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• Liftoff of Orion
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I’m an aerospace engineer in Huntsville, and there’s a Goddard rocket at the space center. The first Goddard rocket exploded immediately when the plume burned through the carbon heat shield. This is the first time I’ve heard the name Nell though; maybe it is on the plaque at the space center and I just never noticed. My oldest daughter starts space camp this weekend. I’m very proud of her. She’s super excited. This is the first time I’ve seen a SciShow video about my job; a bit surreal.
Woohoo PM here livin' it up in Arab - not too far away
When I was stationed at Redstone Arsenal, I would regularly visit Marshal Space Flight Center. Even if the tour or exhibits didn’t change, I loved the time there. Also, at the time, we could see part of the ISS being built in one of the assembly buildings. I can’t wait to go back and see it again. I hope your daughter has a great time!
I hope she has a great time at SpaceCamp, it was awesome when I went to the Academy version!
@@mikkosaarinen3225 oh my goodness, I searched SciShow Apollo and there are so many results! I’m unsure how I missed these. I know what I’m listening to while doing laundry today. Thank you!
@@mikkosaarinen3225 oh I found a moon buggy video on SciShow space. I just volunteered for HERC “moon buggy competition” the other week. I was stationed at obstacle 5 task 1, and it was really interesting to see all the high school and college moon buggies.
Wernher von Braun credited Goddard in 1963 with developing the liquid fuel propulsion system the Germans used in their V2 rockets. He stated, "Goddard's experiments in liquid fuel saved us years of work."
Yeah, it is weird that this connection not only wasn't mentioned in the video, but even denied to exist. Big fail SciFi Show.
Imagine if they could have worked together after the war.
@@AG-ig8uf Denied? They did not mention it is more like it. Also Chineese bambo boom sticks probably saved mr goddard some time aswell, but was not mentioned directly.
@@WerewolfSlayer91 Watch video again, they explicitly said there is no connection between Goddards experiments and modern rocket science, which is based on German rocket engineering in WWII. When in fact von Braun gave a lot of credit to Goddards work, and asked and got technical recommendations and solutions as they were building first rockets.
My grandfather worked for NASA in the 1950s and '60s, retiring in 1972. He worked on lasers, lenses for giant telescopes, and the Lunar Laser Ranging Reflector among other things. He had an award from NASA in the shape of the Goddard rocket that sat on a bookshelf in their living room. I can remember looking at that model from the time that I was a little kid. My grandparents both explained to me that it was Robert Goddard's rocket, but I didn't understand until I was much older that it was the FIRST modern rocket. I have great affection and nostalgia for that little rocket model on its white marble base.
There's been some commentary that the nose-first design was designed for stability as well, believing that it would make the rocket self-stabilize like a pendulum (the "pendulum rocket fallacy"). Did you find any historical evidence that this played a role in the design of Nell? Or is this a post hoc explanation?
Thanks for pointing out this fallacy for people unfamiliar with the topic, like myself. My first thought when seeing the picture was that a stick stays straight when pulled straight, but not when pushed, i.e. basically the same fallacy.
I think the pendulum design is the assumption of hot-air balloon and airship mechanics working for rocketry.
@@szaszm_ if we're talking about structure then yes, tension is actually advantageous, and it does help maintain the rocket's shape better than a compression structure. It only doesn't help with gudiance and control
Correct. Goddard incorrectly believed that the stability of the rocket was dependent on a 'center of thrust', such that the rocket would pivot around where the thrust was. By putting the thrust at the top of the rocket it was assumed that the rocket would pivot around this point and thus always point up. This, of course, is incorrect. Rockets pivot around the 'center of pressure'. This is where the aerodynamic forces are centered on the rocket. Turns out that it makes no difference where the thrust is, just where the center of pressure is (in relationship to the center of mass). Goddard soon figured this out and after a few tries switched the thrust chamber to the bottom of the rocket.
My first thought as a rocket propulsion analyst was that the exhaust was maybe trying to provide repressurization/vaporization heat to the fuel tank (i.e. a giant Coleman stove). But maybe it was just trying to get the weight distribution bottom heavy.
The idea was to make it bottom heavy. Today we call that the Pendulum Rocket Fallacy
Like they always say, a cornerstone of science is learning from failure. Just because some components weren't great doesn't mean others werent marvels of technology
Not used to hearing Rose discuss rockets, but I'm here for it!
Btw, the most successful spaceship class ever, the Soyuz, mostly still uses a fancy match stick to ignite its engines on takeoff.
I graduated from goddard high school in roswell new mexico 😅
Goddard moved his Lab/ testing to Roswell -
Thanks for this video! Very informative
Fantastic presentation of the principles. The clarity with which you laid out the main differences between solid and liquid fueled rockets... Unparalleled.
I have read (some where) when I was a kid that the germans actually purchased Godards designs from him since he was openly selling the "plans" to anyone who would listen and wanted to experiment too.
I had read that one reason Goddard put the exhaust nozzle at the top was that he had the mistaken impression that putting it there would make the rocket stable in flight. The idea was that a weight suspended below the support point would hang vertically like a pendulum, vs. trying to balance a pencil on the tip of your finger. But it didn't work (note it flew 'up' 12.5 m, but sideways about 56 m). Problem was, with no active steering, as the rocket tips to one side, so does the thrust vector and nothing 'corrects' for the tilt.
As a student rocket scientist in school this is really making gears in my head churning 😅
when you press shift while using the offset tool in ksp.
Now you're talking my language!
Thank you Rose. I thought you were more interested in the biological sciences, but everyone can appreciate multiple disciplines. I've known about Goddard since I was a child, and at various times I've contemplated building a replica. But I never did it. I'm glad someone did though.
Goddard was one of my childhood heroes.
Okay. That’s so cool. And I love that pin!!
I came of age during the Russian's Sputnik launch, right through the Apollo program to the moon, and from the start, I read all I could about rocketry. Robert Goddard was the father of it all and space age pioneer.
I'm kinda shocked that a Museum didn't make a replica of it
there are many replicas of it at different museums. The Smithsonian has one.
@@kman2747 Also, according to another commenter who works there, one in Huntsville, Alabama, at the Marshall Space Flight Center somewhere.
I work at the museum of science we have a replica near the planetarium
1:01 That's an illustration from Verne's From the Earth to the Moon, which featured a CANNON. 😛
I wonder how much authors like Vern and others that were viewed as early sci-fi knew about this stuff. Very cool
Science is all about baby steps and I love that
There is a fantastic replica of the early Goddard liquid rocket at the US Air & Space museum. Last time I was there, I spent quite awhile looking it over. From an engineering standpoint, it is just fantastic how simultaneously simple and complex the thing is.
I believe there is also one at the NASA Goddard center, and despite having a couple friends that work there, I confess, I haven't visited since I was a kid; coincidentally, during a hobbyist rocket launch event.
If you want to see this rocket you have to go to Roswell,NM. They have bits of the first rocket and the second one too. The story was when the Smithsonian said that this rocket was not historic enough he re-cycled a lot of the parts into the second.
If you want to know why this and lot of his other stuff (including the infamous "moon rocket " along with Esther's hand sewn parachute) ended up in Roswell. When he moved his test site to Eden Valley,NM , Esther was very active in the local women's club. After Robert's death the club contacted Esther and asked if she had anything of Robert's that she could donate to the new Roswell history museum . Esther basically sent everything that Robert had stored at the family house.
Thanks!
"Independent of Goddard's experiments" is way overstating it. Prior to WWII, rocket experimenters all over the world communicated back and forth with one-another. The German rocket experiments in the 20s and 30s that would eventually lead to the V2 in the 40s were based off a lot of the stuff Goddard had done.
I like this 👍🏻
"2 separate chambers to store each propellent"
monopropellant enters chat
One possible reason he placed the combustion chamber at the nose could be for stability. Having a "pushing" force is far more unstable than having a "pulling" force. We can achieve the bottom combustion far better now with our sensors and computers that can adjust for slight instabilities that they would have little to no way of preparing for back then.
While explaining the liquid rocket type, isn't the illustration in the background @2:30 actually NASA test footage of a solid rocket booster tests? (that is, the opposite of the liquid rocket type)
Love the cute t-shirt, hate that the graphic is partly tucked in. Presentation is flawless as always!
Awww... What do you mean I can't pour gasoline into bamboo? There goes my weekend plans. 😢😂
Cool thanks
I think Estes should work out a commemorative model of Goddard's rocket for its customers.😉
Ha, my ex grew up across the street from the Goddard Space Flight Center in Greenbelt, Maryland. I used to catch the bus there to go to work! 😂
Hi Rose!
Seems to me more like a proof of concept than a final design
Growing up, I always wanted to know how he was able to make liquid oxygen back in the early 1900s. I’m more interested in that then the rocket. I’m guessing he had some sort of compressor and radiator that compressed,cooled, and expanded the air
What does it mean, matches at the end of a pole not being modern? Soyuz is actually ignited that way! :)
Very well presented!
And now I'm itching to play Next Space Rebels again...
It is rocket science 🤯
Those were the days when one person tinkering around in their basement could invent something really new. I expect his budget was pretty small too. Those days may be gone, today's projects take millions of dollars and a lot of personnel, but I hope there are still mavericks coming up with new ideas that many someday morph into something useful and exciting.
While gas and liquid combustion has higher efficiency, solid fuel itself is a denser packing of potential energy and easier to put into a rocket. So, there are definitely trade offs between all three or combinations of them.
Idk why but when I saw the thumbnail my first thought was : UGANDA ROCKET!!!
FYI, when asked the German rocket scientists who developed the V-2 cited the patents awarded to Robert Goddard as their inspiration and guidance for their work.
Wernher von Braun once said that "Americans should know their own hero"
I was told my Kerbal builds would remain private...
Damn was wondering why this wasn’t on Scishow space cause I loved that channel and was wondering why there hasn’t been any videos lately. Welp in ended 3 months ago (from when this comment was written) So sad :(
I would just like to point out that you CAN pour gasoline into some bamboo and light it on fire.
... depending on what you want to acomplish.
Lighting gasoline next to liquid oxygen with a blow torch on a stick? I’m pretty sure I’ve seen some TH-camrs doing the exact same thing. Some things never change I guess.
Nell was a "pendulum rocket" and inherently unstable. That is why you don't see that design in more advanced rockets.
JPL is built in the same area Dr. Goddard experiments were done 😊
So is there any chemical fuel that can react that doesn’t require oxygen, or is oxygen a requirement for any reaction? What I mean is, are there other molecules we haven’t discovered yet that could output the same energy without requiring a separate chemical oxidizer? Or would it just be too reactive to use?
There are monoplanes, there are also lots of other oxidisers exist eg Chlorine, fluorine, nitrous oxide, ozone, nitrogen tetroxide, nitric acid, hydrogen peroxide. Some of these are amongst some of the nastiest chemicals out there and there are many issues using them safely. Recommend you read “Ignition” by John D Clark it’s a great read about the early days of investigating rocket fuel chemistry.
@@spacemanmat Probably an autocorrect fail - the term is 'monopropellants'. Common ones are hydrogen peroxide and mixed hydrazines, which break down into gasses when passed over an iron oxide catalyst.
@@spacemanmat I notice that, other than chlorine & fluorine, everything on that list is a compound containing oxygen. Conclusion (which I already knew from biochem): oxygen is just really, really reactive.
@@CL-go2ji yes, dealing with LOX is particularly difficult, things that you would think are pretty inert suddenly become flammable or explosive. Such as grass or a road if you have leak. Fluorine is particularly bad , the only reason it can be used in a rocket is by pretreatment the metal giving it an oxide layer so that there is now a reacted fluorine protecting the metal from the fluorine. The slightest scratch and it will explode. A lot of the compounds are actually used to tame aspects of the chemicals.
Don't forget about hypergolic fuels as well.
Modern rockets use some kind of sparkplug to ignite, unlike Nell which uses a bunch of match heads
Soyuz : IGOR GIVE ME THE MATCH HEAD, NOW
Now you guys need to talk about Santos Dumont
Goddard move his lab to Roswell New Mexico
Go Go Sci Show!
I still don't quite get why the propellant was under the exhaust
He fell for the pendulum rocket fallacy. He thought it would be more stable, that the weight of the fuel would keep it pointing up. It doesn't actually work like that though.
You had a perfect opportunity to say size doesn’t matter during the first sentence but you blew it… unless size really does matter😮
"Gonna fly on my hobo rocket!"
i used to eat Aeros: I never knew someone had made rocket powered aeros before today. I wonder if they were the mint ones?
Well, I waited all video to see why that rocket was made in that configuration.. and didn't get the answer from that video. I believe is due to rocket stability, as it didn't have active control.
❤❤❤❤🥰🥰🥰🥰🥰🥰🥰
Notification squad let's gooooooo
According to Urban Dictionary:
notification squad
1. Cancer.
2. Something little kids spam on the TH-cam comment section when they get a notification that a video has been uploaded.
That problem answer 😉 by Robert Truax pressure fed rocket or big dumb booster it can big know as sea dragon rocket or smaller
Mr. Von Braun knew much of rocket building. To state Mr. Goddard had nothing to do with the V2
is a lot like stating an overhead valve engine owed nothing to the Otto cycle engine.
I've been to the Goddard Space Center many times. My godmother's husband used to work there.
NASA payload underwent forces of up to 10,000 g, traveled at roughly 5,000 mph (8,000 km/h), and reached an altitude of about 30,000 ft (9,150 m). And it survived the trip The Spin launch suborbital launch accelerator helped achieve this. It's time for Spacex to take points from here so that the launch pad doesn't get ruined. 😅
The arrangement of the tanks below the motor was because Goddard fell for the rocket pendulum fallacy.
Good video explaining the fallacy: th-cam.com/video/Tx4cjP-GRAY/w-d-xo.html
In short: rockets don't have a fixed pivot, so placing the engines higher won't make them more stable.
Fascinating! I had no idea on this ine at all. Also, gotta love the onslaught of guys mansplaining in the comments because its a video hosted by Rose. 🙄
@2:28 What you say is wrong. There do exist mono-propellant rockets (they may use hydrazine or hydrogen peroxide or some other options) and there is even a tri-propellant rocket engine (the RD-701). Also all ion engines, while unusable for liftoff in Earths gravitational well, are also mono-propellant.
Hydrogen peroxide was used as a mono-propellant in Mercury, the first American manned spacecraft, for the capsule's attitude control thrusters.
Came to the comments to comment this.
Ion drive airplanes actually exist too…
Solid rockets are actually a “mono propellant” system…
damn... all i see is the pendulum effect producing an unstable flight trajectory 😅
man you guys didn't talk about the pendulum rocket fallacy
Fuel rockets are 35% efficient today though, ion is the way to go
It really isn't unless you're already in space...
And even then, it really isn't the only alternative.
Also, ion engines still use "fuel", although they forego combustion.
Thats a cute outfit
I'ma tie inna wiiiin
well make a long stick ion rocket, ionic wind
yes works both as airplane and in space
air mixing gasoline as afterburner
well electrostatic rocket then, even fusion reactions on the fly, z-pinch rocket
well van de graaf generator nuclear fusion rocket
its mostly the frame
Von Braun himself acknowledged that Goddard was ahead of the Germans until the mid/late 30s. Imagine if the US had given Goddard some $$$???
How you not gonna mention the rocket pendulum fallacy (i.e. why Goddard put the engine on top)
She's not a show-off. These videos can be limited in details
This video was very coherent without it. I mean the video was clear and approachable and providing deep basic insights to people who didn't knew these things before. Sure would be great if they could do the pendulum fallacy explanation in another episode.
So Goddard's design is more front wheel drive vs today's rear wheel drive :)
Notification squad🎉
*Fart noise*
According to Urban Dictionary:
notification squad
1. Cancer.
2. Something little kids spam on the TH-cam comment section when they get a notification that a video has been uploaded.
@Antonio Usai SIEMPRE EXITEN MMB COMO TÚ 😂
Nice to see Rose Bear Don't Walk becoming better and better as host (at the beginning she was stiff)
The way 2:03 is worded suggests "energy density" is energy per mass but isn't that inaccurate? For example gasoline has a higher energy density than hydrogen but hydrogen has a higher specific energy. Even thou hydrogen isn't as energy dense as gasoline you'd still get more energy from burning a kg of hydrogen compared to gasoline.
Uhm, Von Braun did use Goddard’s designs and improved them to the the V2. So, saying “independently developed” is wrong here.
The other reason why Goddard placed the combustion chamber and thrust nozzle at the nose of the rocket rather than at the tail (as we do now) was because the best way to get a stable flight was if the thrust pulled the assembly from the top rather than pushing it up into the air from the bottom. Without gimbal-control thrust nozzles, there was no way to balance the thrust, and because of the short duration of flight, it wouldn't generate enough speed for directional fins to stabilize the flight through aerodynamic means.
That is what is known as the 'Pendulum Fallacy'. Rockets are nothing like pendulums, and it doesn't matter if the thrust is at the top or the bottom. The motor providing the thrust is fixed to the rocket, so as the rocket turns off axis it turns as well, pulling (or pushing) the rocket course no matter where it is on the rocket.
What matters, when in atmosphere, anyway, is if the center of mass is in front of the center of pressure. This way, the action of the air works to push the rocket straight. For small rockets, you move the center of pressure back by adding fins. For big rockets, you build it unstable and use steerable engines to keep it on track.
No mention of the "pendulum fallacy" demonstrated by Goddard's model? None at all?
1:32 - Yeah, Goddard read and actually understood Newton, unlike those "journalists" who mocked him. (William Moore and Konstantin Tsiolkovsky developed what we now call "rocket equations" before Goddard, and Hermann Oberth later, but they all seem to have been working independently; no Internet in those days.)
BTW, Nell's construction of center of thrust _above_ the central of mass is upside down, but it *does* look intuitively right. Actually, it still look intuitively right to me, although I used to be a physicist.
First American, send her to the moon.
IM GOING TO DO IT
I think there's something to explore here. Right now all the rockets depends on multiple stages to reach orbit since they cannot just drag all the components with them. And that has also its own problems, like requiring a set of engines for each stage. So, what if engines are at the top instead of the bottom? Well, now you only need one set of engines.
obviously the 3000% isn't based on the 2%, just in case
Make the same for the rocket that Germans developed that then got used by everyone to develop the current rockets.
Actually not so bizarre of a design, it makes allot of sense considering the technology of the time.
In KSP I actually do something like this now and then when the cargo is too unwieldy and heavy.
Missed opportunity to give Korea credit for the hwacha, not the Chinese.
Nell's design also kept the rocket fly straight up as it was lifted instead of pushed.
except that it didn't. That WAS why it was built that way, unfortunately that is the Pendulum Rocket Fallacy. Because the nozzle is fixed and in line with the center of mass of the rocket it can't produce any torque so has no influence in how the rocket will turn in flight.
It's okay though, the pendulum rocket fallacy is pernicious and takes careful analysis to notice. Even the man who made the first liquid fueled rocket fell prey to it. 8)
@@gildedbear5355 wow, that's interesting. Once again physics is counterintuitive!
@@glennbabic5954 To put it more precisely, the nozzle is fixed and _approximately_ in line with the center of mass. Designers strive a lot to make the torque zero, but in a real world construction a tiny bit of torque is always there and makes the rocket turn in flight. Without guidance, every rocket would make just an arc in the sky, shorter or longer.
@@u1zha And if the rocket is unstable - that is, with a center of mass towards the front, the rocket will flip around as soon as it reaches any speed.
@@robertbackhaus8911 You mean the centre of mass should be above (i.e. towards the front) the centre of aerodynamic pressure in order to stay stable, otherwise it will have a strong tendency to flip around. As you will learn quickly if you play any Kerbal Space Program.
This rocket blows...... Out the back to thrust this video to the top. 😆
Asbestos for the win.
In general, solid rocket fuel is more energy-dense than liquid rocket fuel
Source?
@@Kyle-gw6qp I can't really tell you where I learned this information, cause I don't remember. I think it was on a space exploration channel, I don't really know. But what I can tell you is that solid rocket fuel is generally more energy-dense and cheaper, however it's harder to control the reaction. Many rockets use solid fuel as its primary source of propulsion, because of its energy density and price, and use liquid fuel to do small adjustments on its course (using smaller rockets)
@@machadinhos "Many rockets use solid fuel for primary propulsion and liquid fuel for course adjustments"
This claim is simply wrong. SLS, Atlas V, Falcon 9, Delta IV Heavy, Arian V, Electron, Soyuz, Proton and the Long March rockets all use liquid fuels in their core stages.
@@Kyle-gw6qp Both solid and liquid fuel rockets use small adjustments to their course through the use of small engines or thrusters, which are typically fueled by a liquid propellant.
Do your homework before claiming another person is wrong haha
@@machadinhos You've changed your claim. Yes, many rockets adjust their courses. Yes, this is often done with the liquid fuels.
But the claim that "many rockets use solid fuel as its primary source of propulsion [...] and use liquid fuel to do small adjustments on its course" is wrong. This is untrue. I can't think of a single rocket where this is the case.
Can you give me even a single example of a rocket that uses solid fuel as its _primary_ source of propulsion and uses liquid fuel for course correction?