How SpaceX lands the Falcon 9: Grid Fins, Thrusters and Engines!
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- เผยแพร่เมื่อ 15 มิ.ย. 2024
- Have you ever wondered how SpaceX controls the first stage of their Falcon 9 to nail a bullseye from 70 miles in altitude and after traveling up to 5,000 mph?
SpaceX has three main systems that help steer the first stage of their impressive Falcon 9 rocket. They are grid fins, nitrogen thrusters and the merlin engines themselves. We show you how these systems interact and then try and land a first stage ourselves in Kerbal Space Program!
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watching this guy wearing a spacesuit in his living room reminds me to be serious about pursuing my dreams
+Alexander Lee you too can be a genuine fake astronaut!!!
+Everyday Astronaut by the way, I didn't mean to be insulting, you do some really cool content. It's just the image of wearing a suit but not getting to go to space that gets to me a bit :'(
+Alexander Lee for sure! I totally understand 😊 thanks for saying hi!! 👍
@@alexanderleeart bro.. because of your comment he doesnt wear it anymore..
Dress for the job you want, not the one you have
Hardware is only a part of the means by which the booster is landed. Navigation algorithms being used in the onboard computer are, IMHO, *much* more significant because really, deciding when/how to tilt fins and when/which thrusters to fire is really at the core of this fully-automated maneuver. It would be great if you could sometime talk about the mathematics of navigation used in landing the rocket. Note that, unlike in simulations, the rocket has to come down in a *moving* sea of air which means it needs to adjust constantly (and not in a way that could be known ahead of time) to stay on track.
Make that visual and you've accomplished a lot!
The control algorithms they use very good, but not necessarily groundbreaking. Similar algorithms have been used on the Mars rover landings, and before that they have seen widespread use in military applications. When you get down to it, the core technologies needed to control the rocket has been around for quite a few decades.
The problem is that you need some relatively complex math and even if you understand the math that governs the landing you would actually still have no clue how they actually go from that to controlling the rocket. I'm using some similar ( but simplified) techniques to control autonomous drones. it's not as complex as you'd expect, but still much more complex than a what a short TH-cam video can properly explain. although maybe I am wrong, I have seen some TH-cam educators explain some really complex stuff simply...
One example oh it being not as complex as you think: you don't bother modeling the dynamic nature of the air. you get the basics right, and as long as you can correct fast enough (with the methods from this video) you can just correct for the discrepancy without knowing where it came from. Having a tight feedback loop is crucial and can actually deal with a surprising amount of unknowns.
tevvya I am quite confident they employed some of the most commonly used machine learning algorithms like neuron networks or reinforcement learning...
Tim Cortesi Yeah...may be not that much complicated, but it is still a delicate work of control since too many factors could affect the stage1 position.
Lets just say that they're both equally important. It's both the hardware and software that makes this all work.
Landing falcon 9s is routine for me on KSP.
You are totes amazeballs!
I do land the falcon heavy however the boosters are all connected. Just makes things simpler.
Same
@@Ethan_Roberts but can you make the fuel reusable?
Same Here!
Can you use metrics ? I though it's a science show :P
this is amurica XD
the aerospace world cares not for the metric system. Cuz you know, slugs are cool
*Can you use the metric system? I thought it was a science show.
Nice video, detailed and layman-friendly and not too silly
+Ian The Pineapple thanks Ian! I'm trying to find the right balance between silly, informative, and not too detailed. It's a constantly changing balance but this one feels like we're getting close 😊👍
There must be a limiting wind velocity for the landing of the first stage on its intended target.
Anyone know what that is, measured in MPH or ft/sec?
Ronald Howell I don't know but I guess that when there is too much wind for landing, there is also too much wind for taking of.
Of course this only applies for landing at the launchside.
125 dislikes. I guess the flat earthers are about. They are afraid of being educated.
Michael Robinson my recommended is filled with moon hoax videos, I have no idea why.
@O F i have 133 iQ said by a professional in a phycological screening
@@robertkiestov3734 it can be both
thank you for making alot of helpful videos.
thank you everyday astronaut 🧑🚀
Wunderbar - Really helpful.
Shout out to your channel. Keep up the good work. Your production value is really great as well as your content, graphics, and you! Really impressed and want to encourage you to keep it up. These are exciting times for space!
+Mike Mueller thank you so much! Glad you enjoy space and thank you for the encouragement 😊👍.
Great fun, thanks. Thrilling to see this marvellous reuse technology - and shown so effectively by your video. Bruce Thomson in New Zealand.
Thank you sir
U helped me out with this video
beautiful. lol i try to do this every time I launch in KSP, it saves a ton of money in career mode. thanks for taking the time to explain all this. excellent editing too!
+anthonyhdean thank you!!! Glad you enjoyed it 😊
Great vid thanks
Thanks for another great video, Tim. Great use of KSP to explain it all, and it sounds like you did your research well. Looking forward to hopefully seeing you make a guest appearance or two on TMRO real soon. Take care, mate, and cheers from Sydney, Australia.
FANTASTIC! THANK YOU VERY MUCH FOR THIS VIDEO. 🚀👍✌️
This video is art
That suit looks more like a U-2 flight-suit from the 1950s. I had an SR-71 full-pressure helmet that didn't look much different. Excellent channel!
Thank you
thanks Tim. awesome video
+samson narokobi thank you! 😊👍
Love your music!
+Micah Taulbee thank you 😊👍
Great video and great tunes as always!
+MrBmnmtfk thank you!!! More music to come 😊👍
I saw the landing on last friday. This is so amazing.
I liked the broomstick manoeuvre at 3:27 :D
+kishore rajendra 😁😁😁👍👍👍
thank you. Very good job !!!
+Gerardo Sessa thank you!
6:12 nice cat!
You are a legend to me personally
Thank you for this quality content stick to it this channel has a potential to get big :)
+Justin Wallace thank you so much 😊👍
Great stuff love your vids found you this weekend and have been browsing a couple vids, subscribed and hitted the bell button! :D
Awesome!!! Thank you! That means a lot :) Lots more content to come :)
Nice spacesuit dude! It looks extremely authentic actually :)
+Andreas Hilmersson it's an old Russian high altitude flight suit. It's been around the world with me for over three years now! - instagram.com/everydayastronaut
My favorite part of the main stage rocket landing back to Earth is that to me it feels like another species is sending a lander to us, like we are the martians. :-) Excellent explanation & illustration on how SpaceX lands their first stage rocket.
+David Mateo heck yeah! Thank you 😊👍
Your videos are really awesome! I just had two questions. Do the nitrogen thrusters be used until landing or just when grid fins aren't useful enough? How do the rockets perform their gravity turn (which attitude control system do they use)?
Aurélien GENIN the nitrogen thrusters are mainly used in low atmospheric pressure (high altitude) and as the air thickens the grid fins provide more force since they use the thickness to advantage as opposed to the thrusters which have an ever increasing resistance opposing their force from the rocket body. Both are used in the transition.
Mike Mueller Thank you for this answer! And do you know how do the rockets perform their gravity turn (which attitude control do they use)?
Aurélien GENIN while the engines are running the use the engine gimbals instead of the nitrogen thrusters.
+Aurélien GENIN on ascent, they only use the engine gimbals 👍
Everyday Astronaut Thanks for the answer
Can someone tell me why the video feed seems to cut off when the first stage is just about to land on the drone ship?
It doesn't always cut out, but it happens fairly often...
Great video Tim! :) -Marty McGuire
Hi Tim, I love your videos! Where did you find the add-on mod of falcon 9? Grid fins etc. Thank you!
MORE KERBAL
This really is amazing, I watched the launch today and when I saw the landing it reminded me of something out of Thunderbird's it just did not look real. Thanks for explaining how they do it, you even had a MOAB in there lol SUBBED.
But the Thunderbirds ARE real! Hehehe
Nice video. Subbed
+Mick McCarthy thank you!
Thanks for this one....as a controls designer, it has always been difficult for me to grasp how the grid fins were capable of making the steering of the rocket look so easy. I mistakenly believed that they were at the bottom of the vehicle. Seeing that they are actually at the top, it is clear now that they more properly represent a variable drag.
Do you talk about the gravity turn and pitch over maneuvers of a rocket launch in any of your other videos? Thanks for the great work!
You seemed to omit mentioning the second flip both in the first explanation and later in Kerbal.
+Timothy Whitehead haha good call... I mention re-orienting it while playing kerbal, but yeah... whoops! 🤦♂️
Loved this video Tim!! I noticed though, that you didn't mention anything about the dog leg maneuver, which seems pretty important as recently displayed in the CRS-16 landing failure. I know you mentioned it in the "What went wrong" video, but you didn't mention it here... Did they not used to do it? Or did you just not bring it up?
I’m not sure I had as strong of a grasp back them. My knowledge base has grown a substantial amount since this old video
Do you do flip maneuver twice, once after separation and then again to make it vertical prior to landing?
where did you get that spacesuit? it's sooo amazing!
Do you know more about to mechanism that gimbals the rocket engines? does it redirect the whole engine or just the nozzle?
+Cameron Cooke there are two hydraulic actuators that can swivel the entire engine in any direction.
GREAT Videos !!!
I'm curious as to what the g forces are inside the Falcon 9 upon landing.
Any idea ?
+Bill Bozeman less than ascent I believe! Crazy huh?
Absolutely.
It would be nice if a method were devised to use the technologies involved here to bring astronauts home from the ISS and future missions to the Moon, Mars, deep space, etc.
Maybe Elon Musk will someday invest in an orbiting fuel station which creates (liquid) oxygen/hydrogen and other needed fuel sources from the atmosphere below the orbiting station.
Sounds like science fiction for now but so did reusing rocket boosters until recent history.
Very nice. Now try this with kOS.
this channel is going to be big.
Great overview of how they control the stage. Do you have any insight to how they target the landing site? Is it a closed loop scenario using a beacon from the site or something similar or maybe a open loop system targeting the Lat/Long? If it is the latter then they would have to have very precise control of the barge!
Sea conditions for a barge landing must, by necesscity, be relatively calm. The landing struts can only compensate for a low degree of tilt.
Under relatively calm sea conditions, the barge would have little difficulty maintaining its position.
The time from launch, to touchdown of the first stage is only a matter of minutes. For all practical purposes, the barge can be considered a stationary & level platform.
Landing at too high a velocity, or failure of a landing strut, pose greater risks than the positioning the barge.
Michael, I'm still getting up to speed on this stuff, so I could be wrong, but that is my current understanding. And I would be more than happy to be corrected by those more knowledgable than me.
I think this is an exciting time for those of us keenly interested in Space flight.
Cool and informative vid. I love your outfit! :) I'm a lil unsure as to how the grid fins work. Are they kind of like a rudder? And having them holey makes them able to withstand the friction?
+alucinare thank you! They're exactly like a hundred little rudders or tiny wings stuck together. It's mostly that way so they're compact. They do provide more drag than a traditional fin, which in this case is a good thing.
Ohhh I think I get it. Does it have anything to do with the surface area exposed to the air?
Yeah, it's a very compact way of presenting a lot of surface area to the air. The other advantage (which isn't obvious at all and gets into the complexity of flow dynamics) is that they work really well in supersonic velocities and subsonic velocities. Unfortunately, they lose a lot of control authority in the transsonic region because the air effectively blocks the small openings and most of the air flows around the entire fin (rather than through the miniature holes).
Fascinating! Thanks for the extra info.
Let's hope SpaceX does this
With current technology and good collaborating, today we can make everything's possible.
That's helpful thanks. You clearly explained the first flip the first stage at 4.35, but forgot to explain it's second flip at 4.50 so the engine were pointing earthwards to slow it down. Otherwise it was great thanks
If you watch NASA's videos of atmospheric retropropulsion testing in a hyper sonic wind tunnel, you can find out that reentry burn not only slow rocket down, it's also pushes both hot dynamic heating and hyper sonic shock wave away from vehicle. Also rocket plume shape is important, single engine burn in the NASA test made rocket go faster! Very fat plume with three engines, where the outer ones were pointing some decree sideways, worked best.
+HVM I heard that it'd speed up during reentry with one engine on an episode of Orbital Mechanics Podcast! That's so wild.
How are the fins significant enough to do any turning with them being grids?
How does Falcon9 Stage1 not burn up? The shuttle controlled angle of entry into atmosphere and used heat tiles to land safely.
+Les Pinto the shuttle was coming in from orbital speeds (17,500 mph) and the first stage only gets going up to ~ 5,000 mph. It also does the entry burn which slows it down enough to not get torn apart.
You should talk about the autonomous fligtht computer
Why does all space nerds got cats!
+CptMikeTango great question! Mine came with my wife. Inherited the little beast 😉
scott manley has a cat?
CptMikeTango Scott has a dog.
tayfun gürgen Oh OK, you mean He has tarned his cat as Dog🏭↩🌠
It's the cats that have all the space nerds.
can I ask a question?
so the first burn acts like a shield of the rocket boosters against re-entry to the atmosphere because asteroids were pulverize on that zone? does the ventilation of your suit working? seems like you're not sweating inside that suit. : )
rybaxs if you hit air at very high velocities it gets hot and even hotter until the point the air ionsizes, and ionzised air has a red glow (hence the brightness from the Space Shuttle’s re-entry and asteroids burning up). What the re-entry burn does is deflect this air and prevent the large majority of it from contacting the booster. The burn also slows it enough that when it stops residual speed doesn’t do the same again.
Im just gonna mention that Kerbin (Ksp Earth) has a atmosphere that is half as thick as earths. Its much easier to escape and re-enter.
3:01 been there and took a picture with that moab lol
On the May 11 launch they left out the boostback burn. Which (I assume) means that after stage sep stage one kept going East at 8,000 km/hr and away from the drone ship. Please explain.
No, you’re seeing stage twos speed. Stage one slows down until it hits apogee, then speeds back up to about 1,700 m/s and falls back and they put the drone ship about where that parabolic arc is.
But you said at stage sep the rocket is going way more east than upwards (obvious from visuals and telemetry). So it's going to go faaar eastward and away from the ship, under no real control of trajectory (fins useless in vacuum and the thrusters only affect attitude).
And how do they figure for the various wind layers (some reach 200 mph and are unpredictable). The fins have no control in a vacuum and the thrusters have none (not enough) in the atmosphere so - even assuming you somehow home in on the ship (impossible anyway) - for the last 1,000 or so feet, the engine gimbal is the only control. and the gimbal cannot adjust attitude without screwing up trajectory; so the last 1,000 feet cannot be under real control. Your scene with the broom actually shows this.
Also, the thrusters are for attitude control not heading. Since there is no airfoil surface on stage 1 there cannot be lift, which you need to properly 'steer', especially from 70 miles up with all the chaos theory elements between sep and landing (the fins are for attitude control). Sorry, but something is very fishy about Spacex. Are you aware of that? (Kidding: of course you aren't.)
Come on, Tim, you can do it! (It's your JOB.) Answer my concerns!
What kind of control do people have over the boosters as the re-enter the atmosphere and land?
you want to trust some engineer to land a 15 story missile? They are completely computer controlled, they would never get close by hand
your spaceship on Earth video got loads of views!
Great job! Can you explain whether other rockets use the same technology to re-use their first stages? Thank you!
+Pann Hon someday perhaps I'll do one on Blue Origin's New Shepard or when they launch their New Glenn. They're the only ones doing anything even remotely similar.
Can you do a video on why the Space Shuttle didn't work out
+Michael Derrick absolutely!!! That's on my list 😊👍
well, the reason is simple:
How many tiles did the heat shield of the shuttle have?
10,800
How many DIFFERENT tiles did the heat shield of the shuttle have?
10,800
The failure of ONE of these tiles leads to a total loss. And after EVERY flight at least 200 had to be replaced.
Plus bear one thing in mind: To get the financing of the shuttle completed the USAF demanded the ability to intercept and capture russian spy satellites to take them back to earth. That made the shuttle so bulky and inefficient.
Fun fact: Since the shuttle is officially retired the orbit of the ISS could be raised to 400km - as the shuttle was unable to reach that altitude with its intended payload.
Oh, please go into how the Air Force basically crippled the program by demanding a 1000 mile crossrange capability and then went with rockets instead.
if the change involves such a drastic increase in complexity and cost so the whole program is FAR from EVER being efficient (the original planning to make shuttle launches profitable and cost-efficient was around 2-3 launches per WEEK. That's however how and why the movie Starflight was built around...filled with lots of propaganda around the Shuttle).
If you take a look at the original design suggestions regarding a Space Shuttle you'll find LOTS of concepts which were A LOT LESS bulkier. In fact, the original "shuttle" was intended to look much like the X-37
Lol so dope
+BenRealVsWorld 😘
Why does the spacex bfr need to refuel? Can't it carry enough fuel?
Everyday Astronaut → Does the 'navigation system' for this booster use GPS, some kind of radio beacon at the landing site, or something else?
+RocKiteman _ 2001 it's basically purely GPS and a radar altimeter at the end. I believe the drone ship and F9 do communicate and share a signal, but it's not for navigational purposes.
Everyday Astronaut → Roger all that - Thanks!
There is a two-way downlink from the rocket to the drone ship, as it just uses the same protocol as any other ground station relaying telemetry.
I've been watching the SpaceX Falcon 9 launch videos and I'm confused as to how the first boost back burn supposedly reverses the direction of the stage 1 but somehow manages to not dip below 1600 km/hr. Are the numbers they post on the screen accurate or am I missing something? Shouldn't it go to close to 0 and then back up? And that boost back burn seems to last only 10 seconds. If it takes 2 and a half minutes to accelerate to 6000 km/hr shouldn't it take at least that long to reverse the direction?
+reuvenbrown the boost back burn negates the horizontal velocity only. The booster is still moving upwards rather quickly so it's total velocity isn't quite negated. Also, since it's nearly empty and doesn't have the second stage and payload on top, the boost back burn is much shorter and easier. Don't forget, they fall back to earth for free, they only need to change their horizontal portion and that's it!
Q: How do rockets navigate in (deep) space?
nice vids!
Does anyone know the velocities of the first stage before re-entry? And how much speed the re-entry burn needs to take off before entering lower levels of the atmosphere? It amazes me that the concave shaped engines can survive this process! Can wait to see what Block 5 is capable of! Also, love this channel. Keep it up!!
This video is all about first stage
th-cam.com/video/GhaD8XLoOl4/w-d-xo.html
Pretty sure you were using MechJeb for the KSP portion
+Lego Kid 104 only on ascent so I eliminated variables up until stage sep. Mechjeb sucks at landing or else's I absolutely would've used it. Check my previous kerbal videos for more game play.
how do they control fuel/oxidexer velocity and thrust
So how do the grid fins actually control the motion?
Please make a video how dragon 2 capsule is landed too, i don't see things like grid fins on there
+Ravhi Rizaldi Dragon 2 hasn't landed (yet), they've done propulsive tests and an abort but no actual landing for now. That'll start happening soon. I'll also be making a video about how Dragon 1 and 2 differ soon 😊
This is why SpaceX uses mechjeb ;)
What are the landing velocities?
I always forget how big rockets are, like when I see the drone-ship at 1:16, my brain thinks it's only a few feet long
The video after the one I'm working on is alllll about the scale of rockets to help people understand how stinking HUGE they are
That video is going to be stinking COOL
I've always wondered how they control their rockets.. Could you make a video on this topic?
+Eliaslinde you mean on the way up?
Yep, that's what I meant :3
I want to know if they have programmed their rockets to control automatically (that's probably what they do) and if they have any manual control in critical cases. Sorry if my question does not make too much sense :p
+Eliaslinde totally makes sense! They're 100% automatic. They constantly adjust themselves to maintain nominal flight. The only manual override a human can do is authorize a self destruct sequence
Alright, thanks! 😊 I was a little confused on how exactly they control their rockets, because I too play KSP, and that happens manually and in real time. There is also a map where you can set up maneuvers. I assume they have something similar, but one of the giant differences must be that everything does not happen in real time.
They are 100% automatic. But, I think the humans have more control than self-destruct. It is my guess, so don't consider it as a fact.
I think humans maybe also able to control incase of other issues like what to do in case of less than optimal performance from the engines or if there is some other correctable issues
So how does Falcon 9 know where to land? Just GPS coordinations?
3:03 thats a bomb
You forgot to mention the low center of gravity of the Falcon 9's dry mass which helps orient the rocket while coming down the atmosphere.
All rockets at this point have a real low CG, engine are heavy and there is minimal to no fuel left to push CG up on the rocket
How many times can a rocket be re-used? :)
¿Cuando sera el primer vuelo del Falcon Heavy?
+Didac Molto Finales de otoño o principios de invierno
What is that white smoke that circles the rocket before lift off?
+Carlos Eduardo check out my video beginners guide to spacex!!!
it is steam from the million liters of water there
@@EverydayAstronaut. Thank You for the incredible support!!!!!!
What mod are you using?
How many computers inside Falcon 9? How does the computer on the 1 stage Rocket communicate with the main computer ( if it is on the top of the rocket) - I ask this question because the first stage of the rocket will detach soon?
+yxhankun great question. Both the first stage and the second stage have fully stand alone guidance and navigation units. I'm not sure which is doing what during which portion though. Good question. I'll prod around
Q1 Musk must have instructed ( or he is being informed by his engineers ) his engineers to use the Fastest ARM single board computer with CAN bus...( in arduino term or computer technology) to be 1st stage and 2nd stage. Am I right? Q2 Are they using wireless connection between 1st stage and the 2nd stage, if not . Q3 How do the cables being unplugged within the rocket? Q4 How do cables survive in space? There are so many terminals on the ground base, the computer(s) on the rocket are not going to serve all the terminals like tell every terminals "I am fine, I am at a height 99999 meters above the sea level ...flying at the speed Mark I...etc". Rocket computer is busy at her own tasks.... at 5001 th microsecond I am igniting all 20 the explosive screws around the 1st stage, preparing the detachment and at 5002 ms I am igniting the "cable detachment box". BTW I played once a rocket costed $12.00 CAN in Canada from Kmart after I graduated from university.
How do the grid fins work
Hey,
Why they are using Nitrogen in specific??
Thanks
Nitrogen is a inert gas and is readily available, the only other option would be to use a monopropellant and that can get dangerous
How does the first stage navigate on its way back?
It has nitrogen thrusters on its upper sides , grid fins on upper sides and the gimbaled ( like thrust vectoring ) main engines and of course gravity . Using these it can maneuver itself .
How to design the grid fins?
When would max Q on the first stage re-entering be?
+Andrew Webb that’s a good question. I would assume it’s sometime after reentry burn and landing burn. The vehicle slows down a lot from aerodynamic forces during this point.
Komrade Kat :)
You play KSP on MAC? R.I.P.
1:25 I thought that was real footage for a fraction of a second
more info on nitrogen thrusters please
Aggressive enough?
What's the name of this cool simulation software?
+Mathias Obetzhauser Kerbal Space Program! It's a game/simulator and it's the best!!!
No graphics mods in ksp? I will literally die without the astronomers visual pack
how does grid fins work ????
hey, quick question, can Spacex re-use their second stage? or does it just crash and burn? thanks
+Jonny Oates excellent question, it's funny you ask! That's the topic of my next video!!! Stay tuned 😊👍
Everyday Astronaut Cool, I'm looking forward to it! Loving your channel.
+Jonny Oates thank you! That means a lot 😊👍
The short answer, by the way, is that it currently either stays in orbit or deorbits itself - but SpaceX eventually wants to reuse it. I'm sure Everyday Astronaut will cover this in much more detail though :)