Not to be "that guy" but this is just a basic intro to orbital mechanics, and there are things that you probably wouldn't have learned from KSP about orbital mechanics, even assuming everything as a "patched conics" model. In reality, orbits aren't even conics, even if in many cases a conic is a decent approximation for short timescales.
After a 10 month hiatus to get married, buy real estate and create this animation, I am back! At the time of my last post, there were just over 13,000 subscribers, and now over 40,000! 100,000 subscribers...were coming for you! I'm so grateful to everyone who has watched my videos and patiently waited for the next one! I really hope you all enjoy this one! Cheers!
Great video! I’ve watched it several times already and shared it on Kakao, Twitter and Facebook. (I study OM). If you would like to prefect the English in your presentations, to make your work academically bullet-proof, contact me.
Without knowing crap about orbital mechanics, you brake to drop lower where you'll go faster. Because the higher you're up the longer your orbit. And you can't go faster in a given orbit than it's speed. If you speed up you go higher.
@@ChiliFrog Suppose you're in an orbit next to a space station. If you have a burn in the prograde direction of the orbit you will increase your angular velocity, moving ahead of the space station--Forward. This will cause an imbalance between your angular velocity and the pull of gravity at the radius of that orbit, which will move you to a higher orbit--Out. So forward is out. Once you reach the desired height of your new orbit, you make a correction burn to balance your angular velocity with the gravity at the higher orbit. Because of orbital mechanics, the space station at the inner orbit has a greater angular velocity than you do. You are moving backward relative to the space station. So out is back. If you now decide to make a burn that is retrograde to your orbit--Back--your angular speed will slow. This will cause another imbalance between your angular velocity and the pull of gravity at the higher orbit. You no longer have enough angular velocity to maintain that orbit. Gravity will pull you in toward the object you are orbiting. So back is in. Finally you decide to make another burn to stabilize your lower orbit. You must increase your angular velocity to balance gravity at this lower orbit. Your new orbit is lower than the space station's orbit; therefore, you angular velocity is greater than the space station's. You are moving forward towards the space station because of your lower orbit. So in is forward. The circle is complete. You might enjoy reading "Integral Trees" by Larry Niven. BTW Niven's quote may actually start with one of the middle clauses of what I quoted. It doesn't matter where you start on the circle. If you follow all the progressions, you will complete the circle.
Also, Heinlein had "The most cock-eyed, contrary to all common sense, difficult aspect of ballistics around a planet is this: To speed up, you slow down; to slow down, you speed up." From The Cat Who Walked Through Walls'
Cool video, great animations! I learned orbital mechanics playing Kerbal Space Program, and I love it so much I'm in college now to become a physicist and hopefully work somewhere like SpaceX. Love that you used the Dragon capsule as your ship!
@somedude4805, I've never played KSP. Sending well-wishes on your endeavors to become a Physicist & hopefully work someplace like SpaceX! I've never had any schooling on physics principles etc., so I'm a "n00b" at these things just gathering bits and pieces of information over time. I think the video was very helpful with the animations in demonstrating the differences in kinetic/potential energy and the orbits expressing how spacecraft behave in relation to the Earth's gravity, inertia and any applied forces such as the "burns" initiated by the vehicle's engines. He didn't demonstrate the "anti-normal burn" but I assume it has the opposite effect of the "normal burn leading to an inclination of the orbit." I know he's a "commercial businessman" but I would've thought Elon would be working on the "artificial gravity" aspect more than ironically "Starship." I'll admit I'm a fan of the "Star Trek" series and have always dreamed of a day when we would have some means of creating that artificial gravity environment without the need for "spinning."
@@zenithperigee7442 If you want to grasp orbital mechanics better, KSP is a really great way to do it. I highly encourage you to give it a try. I never knew anything about orbital mechanics and just tried out KSP while waiting for Starfield to released because most other space games I had already played at least a little. It was very hard to learn at first but now I can transfer to other planets and dock with other spacecraft pretty easily. To your point about artificial gravity, I'm afraid we wont see it in our lifetime. I would even go as far as doubt it'll ever be possible. Considering most of Earth's gravity is caused by the core, you'd need either an unimaginably large craft or some kind of technology to basically break the current laws of physics. And if either of those things were possible, then you'd need some way to keep that gravity ONLY on the ship and as soon as you go out the airlock, you're in zero-G again. Otherwise, having a gravity generator that large and that close to any planets would throw off the orbit of either the planet around the sun or the moon of the planet. Imagine an earth-sized gravity field at the altitude of the ISS. If we were on that ship and in the right spot, we could send the moon into a more elliptical orbit and either slingshot it away from Earth or closer to Earth. Plus, that gravity field could cause Earth to get pulled away from it's current orbit around the sun and have HUGE repurcussions for the entire planet. We'd be the sole reason the world ended. Kind of a cool premise to a sci-fi "end of the world" movie, though.
Fun fact that explains why Armstrong was chosen to be the first person to land on the moon; his doctoral thesis at Purdue University was titled "Lunar Orbital Mechanics". He undersood it better than anyone else on Earth.
Thanks! Your explanation is excellent, elegant and accurate! I tend to get technical when I explain it to non-scientific types, but Buzz (he actually changed his name) used to be called "Dr. Rendezvous" because he could figure orbital mechanics in his head, and he is one of my heroes!
Very well done! Have you considered a similar explanation for planetary slingshots? I think a lot of sci-fi writers and even news outlets get it wrong.
@photogagog, I admit I enjoy "sci-fi" but I would love a quality explanation/animation of "planetary slingshots!" IIRC this was the principle used to help the Parker Solar Probe travel towards the Sun nearing an unbelievable ~400,000 mph by the time it would reach it's orbit.
It seems like in a sligshot, the gravity that pulls the object in will be the same as the object leaves, so any gains in speed would be lost. The only thing that adds (or reduces depending on relative direction) is the speed of the planet's orbit around the Sun?
One suggestion is that towards the end of the video when describing the ISS rendezvous, to start the retrograde burn from the same initial circular orbit starting condition, instead of trying to correct the previous prograde burn. That way, it will be more obvious what the two difference are and how to intercept the ISS.
I know you commented this a year ago but the point of the prograde burn was to demonstrate that with these kinds of things are not as straightforward as "accelerate towards target and you will arrive there." Like it is on Earth. He talks about how you have to slow down to go faster and speed up to slow down at a previous point in the video, so he demonstrates both. But yes, obviously a prograde burn followed by a retro burn would be significantly less fuel efficient lol.
Just a caution for those looking to understand more carefully. There is a difference between absolute velocity and angular velocity. By doing a prograde thrust to apply force you are increasing the absolute velocity of the craft and decreasing the angular velocity. Another term used in the space industry is "ground trace" that applies here. If you take a straight line from the center of the earth (this gets more complicated as the earth is an oblate spheroid rather than spherical, but that is another topic) to the spacecraft at any given instant the point on the ground (earth's surface) that intersects this line will "appear" to speed up or slow down relative to time. This is a depiction of angular velocity. By increasing the area of the ellipse, the spacecraft must increase absolute velocity, which will expand its total distance from the earth short of escape velocity. In other words, prograde will always increase absolute velocity and decrease angular velocity (even if it does reach escape velocity--i.e. no longer in orbit) and, conversely, retrograde will always decrease absolute velocity and increase angular velocity (up until the point that the orbit remains outside of other physical forces--particulates of atmosphere, space junk, solar winds, and electromagnetic drag, etc.). For reference, geosynchronous and geostationary orbits are much "faster" and "higher" than other orbits, but the angular velocity is nearly zero (it appears to stand still in the sky from the ground. Much higher orbits are still possible, but they will then appear to go "backwards" (negative angular velocity). In other words, the earth's rotation will progress farther than the rotation of the satellite orbit, from an angular or ground observational perspective.
Also, just for reference, spacecraft maneuvers typically do two prograde bursts to go from one near-circular orbit to a higher, "slower" (less angular velocity/greater absolute velocity) near-circular orbit. As shown in the animation, it creates an initial highly elliptical orbit plane and then an alternative highly elliptical offset at the "highest" point above earth that "rounds" out the orbit. (There is a lot more involved in mathematics, physics, rocketry and chemistry to this than simple calculations of perfectly frictionless pool table physics, but that is the gist of it.)
Another confusing part of this is it is all relative. If you have a polar orbit (where the angle of rotation is closer to north-south orientation than equatorial orientation), the ground trace gets much different and complicates the discussion. However, similar physics is involved, but the ground trace, launch characteristics and orbital dynamics require different sets of skills and typically different teams of people.
The only thing I would change is to show the planet inside the orbital paths rotating about its axis, showing how the suborbital position -- the Earth coordinate -- moves with respect to the orbiting body. Depending on the orbiter's inclination, the North (or South) Pole would be in the center of the spherical planet when the craft is orbiting above the Equator, but would be offset from such a vertical position when the craft is orbiting in an inclined plane relative to the Earth's equatorial plane, with an Ascending Node and a Descending Node associated with this inclined orbital path. Also, depending on the period of the orbit, there would be certain times when the craft would appear above the same point on the Earth below, say, if it orbits 16 times per sidereal day, once every 89 minutes 45.25 seconds. If a spacecraft orbiting above the Equator were to be above 0 deg N, 75 deg W at one point, then after 16 such orbits it would again be above that spot, one sidereal day later. Animating the spinning Earth -- and including a terminator, with a Day side and a Night side -- and having a red wavy line representing the Ground Track as the planet wobbles like a top, now THAT would be cool to see. Maybe a later video could depict these things . . . ? 😎
Beautiful and comprehensive explanation of difficult concepts. High-level math and physics explaned in a way a child could understand it. Very well done!
I would add that when you do a normal or anti-normal burn, you also add a small bit of prograde velocity to your new orbit at the new inclination, slightly raising your apoapsis
Not if you keep your craft pointed precisely in the normal direction during the entire burn. If you park your craft in an orientation and then do a normal/antinormal burn, though, it will instantly start to have a prograde or retrograde component of the thrust vector that will increase as long as you keep firing your engines, since you will no longer be perpendicular to your orbit once you start changing its plane.
@@sciencecompliance235 It will no matter what. Depending on how long the normal/anti-normal burn is, you can get the apoapsis back to it's original altitude, but that's usually not the case
Wow, this video is amazing! Iam in my first year studying physics where we already talked a bit about orbital mechanics but this video is an absolutely gem to get a better understanding of what is really happening… Thx for the effort, you got my sub!
*_Former Boeing... your videos are well thought out, easy to understand, even for non-engineers..._* The ISS loses altitude due to friction with Air Molecules. Even at 250 miles up, some Air Molecules remain. NASA has to change speed and direction of ISS to get it back in it's normal orbit. *_ISS experiences 90 percent of Earth's Gravity even at 250 miles altitude..._*
Wow, thank you very much Sir. Please do part 2, showing how to launch to iss, preflight path, which degrees or angle, how to calculate when to launch. Thank you. I wish to understand that.
2:56 I Calculated And The Altitude Of The Orbit Is *1/4.5 Earths,* Which Is *2834 km* Altitude, And The ISS Orbits At An Altitude Of *402 Km* Above The Earth, And The ISS Takes *90 Minutes* To Complete An Orbit, And 2834 / 402 = *7,05* Times Higher Than The ISS, And 90 Minutes x 7,05 = *634,5 Minutes,* Then The Spacecraft In The Example Has An Orbital Period Of *10,575* Hours! Which Is *2,27 Times Less* Than The *Rotational Period* Of *The Earth!*
I’ve watched quite a few videos, each attempting to explain orbital mechanics. I kind of got what was being instructed but, not to a complete understanding. This video however, explains the concepts perfectly. Thank you!!
"Well cant you just fire your engines at earth instead of a prograde burn? Well lets do it and see what happens" I cant stress enough how important this is and how schools should be taking notes from this guy.
It makes you appreciate so much more the brilliant people at NASA that calculated the Apollo missions' Earth orbits, trans-lunar and trans-earth injections, lunar orbits and lunar orbit rendezvous, all with slide rules, pencils and paper. IBM mainframes helped, of course, but the lion's share was accomplished without computers. Amazing.
Fun fact that explains why Armstrong was chosen to be the first person to land on the moon; his doctoral thesis at Purdue University was titled "Lunar Orbital Mechanics". He undersood it better than anyone else on Earth.
Ive never felt so smart. At one point in school our teacher played this video in class. After hours of KSP, orbital mechanica are just so simple to me, yet my entire class was completely dumbfounded that you cant just apply force in the direction you want to go.
I mean, if you're in orbit and you shine a light at the ground (at right angles to your orbit), the light will reach the ground. So at some point between rocketry speeds and the speed of light you really can just thrust where you want to go.
I don't know your physics teacher, but this explanation is VERY basic and provides no actual equations for calculating the precise character of these effects.
I'm not sure if I would have flung myself far away first or not, but for sure I would have definitely ended up a brief fiery ball of beautiful brilliance streaming somewhere over Tajikistan, or maybe Texas! Can we have a moment of silence...
While this makes a lot of sense, I still can't undestand the maneuvers in small scale, take for instance those final moments of approach with the ISS, you're 5 meters away from the station, you actually have to trust away from the station to get closer to it? Does the famous iss docking simulation is wrong on their physics? Because I managed to dock on my 1st try, and quite a few tries later, and while initially I do in fact have some weird controls, the later maneuvers are quite straigh forward, tap accelerate to go forward, tap draft in Y to move right or left...etc.
Sweet video! Just FYI, your animation actually has dragon burning the wrong way. It doesn’t use the super Draco’s for orbital maneuvering, but the Draco engines facing more towards the top of it
simple yet effective. One small error: the spacecrafts don't rotate. They would keep the sine direction relatively to space, so they wouldn't be always heading towards their motion direction.
@@AsaSpadeSS i mean they do rotate, when you want them to do so, using thrusters. They don't just point forwards always, like airplanes do. An airplanes point forward because of aerodynamics, but in space there's no air. If you leave a capsule in orbit and not rotating, it will keep that direction relatively to space (not earth)
@@giovannicorso7583Aaaand if you leave a capsule in space with the correct angular velocity it will also stay that way. There is nothing impossible about what's depicted in this animation.
@@beanieteamie7435 you can, but simply why? Making animations like such is not wrong, but makes people believe that that's how it works, while it is just a very edge case (that you just described)
I've flown Orbiter Sim and KSP for years, and I don't think I've ever done a radial burn (at least on purpose). They don't seem to be very useful for orbital rendezvous purposes.
These Kerbal people... I don't live at my computer (I live in my Quest air linked to it.) So I use my phone: _"Spaceflight Simulator"_ is a free game which doesn't collect data or have ads. You build your rocket, launch it, and try to get into an orbit. Adding thrust will change the orbital trajectory exactly like this video. Build too big and you'll run out of fuel (and crash) or not even get off the pad. Same if you're too small. But with enough stages and ejectable boosters you will get into LEO. But then the goal is to manipulate that orbit into an elongated oval which crosses the moon's orbit at a point where the moon will be when you arrive. If you prebuilt a rover you get to drive it on the moon surface. I've never managed the fuel correctly to land (and parachutes don't work on the moon for some reason). Mostly I just end up running out of fuel and forever orbiting the sun. Maybe one day I'll make a footprint on the moon. Who knew rocket science was so hard. Free, data safe, and fun. In Google Play for Android.
@@SOR-05 It sure is. Being 2D makes the learning curve very shallow. Yet it still features enough physics to be fun. It's a great way to pass time on your phone.
I'd like to see a VERY slow orbital burn. Show velocity as it goes. First you slow down. Then, at some point in the orbit you gain back that speed. Then you reach the bottom with a lot more speed. To circularize you need to slow again, but the final speed required is still more than the original. Going out to a larger circle would be fun to see in tedious slow-motion too.
Time is your greatest enemy. You can get anywhere you want with a gravity assist. Lining those celestial bodies up to get there is the witch of the matter.
It’s pretty obvious that the fine details of orbital mechanics can get really complicated. I’m a big sci-fi fan, Star Trek, Star Wars and many others, and it seems like most of them ignore this stuff. A spacecraft simply takes off from the ground and is shown simply flying out away from the planet like it’s nothing. Or, several spacecraft near a planet or shown maneuvering easily and quickly all around each other. Pretty unrealistic, but maybe someday we’ll have technology to make such things possible.
That is an extremely helpful video! I can't wait to master the maths behind all of these. I've independently thought out the retrograde and prograde burn(I came to know the name just from this video) and also the mathematics behind it!
So good! Where is the rest of this 20 part series? 😆 Srsly though: Please more of these. Hohmann transfer, actual docking maneuvers, orbital injection, all of it. pleeeeaaase 🥺
I have a few questions when you were explaining in the beginning about kinetic energy, theirs no explanation on why the velocity decreases, and increased the way it did. can someone please help me out?
Great question, let me see if I can help you out. If you’re referring to the point on the roller coaster….when the kinetic energy is lowering, the train is increasing in altitude and therefore increasing in potential energy. It’s simply an exchange of energy. Kinetic energy lowers when the speed does because kinetic energy s calculated through multiplying the speed by mass! Hope this helps!
My favorite orbital mechanics game (Space Agency, on mobile) had it all wrong when it comes to radial burns. Now I see why my friends who are KSP nerds didn’t like it…
Awsome explanation and graphics. Briliant!!!! I wish you add something about rich ISS or any other object in space. I mean is not like cars break and accelerate to rich others. With orbits this dont work. Bside you rich the speed of ISS if you are not in time you can caught ISS*that is why need retrograde and prograde acceleration but when?) I would like see how to cach up the ISS and dock not just fallow it. And about launch (orbital inclination and diference betwen launch shoot and launch orbit with the same amount of fuel.(when go 90º up and nothing tangent speed))
Fun fact that explains why Armstrong was chosen to be the first person to land on the moon; his doctoral thesis at Purdue University was titled "Lunar Orbital Mechanics". He undersood it better than anyone else on Earth.
Love this, KSP really made me understand orbital mechanics
Dude yes its crazy watching this and realizing I know most of this stuff already
True Bro, Mainly If you play with principia. That game is insane
LOL yea same
Not to be "that guy" but this is just a basic intro to orbital mechanics, and there are things that you probably wouldn't have learned from KSP about orbital mechanics, even assuming everything as a "patched conics" model.
In reality, orbits aren't even conics, even if in many cases a conic is a decent approximation for short timescales.
Orbiter 2016 more accurately depicts OM
I've wondered about this for 20+ years. Great explanation. You know, this was most of Buzz Aldrin's Ph.D thesis that he never revised.
He very literally wrote the book.
@@ojonasarJust out of curiosity, why would he revise it?
@@clayz1 His thesis got used to get him to the moon, and back, so it’s fair to say it worked.
@@ojonasar It was Magrant17 who suggested that there was unfinished work on his theses, or a mistake of some kind. I didn't say anything of the sort.
After a 10 month hiatus to get married, buy real estate and create this animation, I am back! At the time of my last post, there were just over 13,000 subscribers, and now over 40,000! 100,000 subscribers...were coming for you! I'm so grateful to everyone who has watched my videos and patiently waited for the next one! I really hope you all enjoy this one! Cheers!
You totally deserve 100k subs. Very high quality, concise, intelligent stuff.
great video wow
Great video! I’ve watched it several times already and shared it on Kakao, Twitter and Facebook. (I study OM).
If you would like to prefect the English in your presentations, to make your work academically bullet-proof, contact me.
Congrats!
Without knowing crap about orbital mechanics, you brake to drop lower where you'll go faster. Because the higher you're up the longer your orbit. And you can't go faster in a given orbit than it's speed. If you speed up you go higher.
Great Video and explanation.
So to summarize in a nutshell, and to quote Larry Niven, “Forward is out, out is back, back is in, and in is forward.”
That made my head hurt!!
What?
@@ChiliFrog Suppose you're in an orbit next to a space station. If you have a burn in the prograde direction of the orbit you will increase your angular velocity, moving ahead of the space station--Forward. This will cause an imbalance between your angular velocity and the pull of gravity at the radius of that orbit, which will move you to a higher orbit--Out. So forward is out.
Once you reach the desired height of your new orbit, you make a correction burn to balance your angular velocity with the gravity at the higher orbit. Because of orbital mechanics, the space station at the inner orbit has a greater angular velocity than you do. You are moving backward relative to the space station. So out is back.
If you now decide to make a burn that is retrograde to your orbit--Back--your angular speed will slow. This will cause another imbalance between your angular velocity and the pull of gravity at the higher orbit. You no longer have enough angular velocity to maintain that orbit. Gravity will pull you in toward the object you are orbiting. So back is in.
Finally you decide to make another burn to stabilize your lower orbit. You must increase your angular velocity to balance gravity at this lower orbit. Your new orbit is lower than the space station's orbit; therefore, you angular velocity is greater than the space station's. You are moving forward towards the space station because of your lower orbit. So in is forward.
The circle is complete. You might enjoy reading "Integral Trees" by Larry Niven. BTW Niven's quote may actually start with one of the middle clauses of what I quoted. It doesn't matter where you start on the circle. If you follow all the progressions, you will complete the circle.
Also, Heinlein had "The most cock-eyed, contrary to all common sense, difficult aspect of ballistics around a planet is this: To speed up, you slow down; to slow down, you speed up." From The Cat Who Walked Through Walls'
Cool video, great animations! I learned orbital mechanics playing Kerbal Space Program, and I love it so much I'm in college now to become a physicist and hopefully work somewhere like SpaceX. Love that you used the Dragon capsule as your ship!
@somedude4805, I've never played KSP. Sending well-wishes on your endeavors to become a Physicist & hopefully work someplace like SpaceX! I've never had any schooling on physics principles etc., so I'm a "n00b" at these things just gathering bits and pieces of information over time. I think the video was very helpful with the animations in demonstrating the differences in kinetic/potential energy and the orbits expressing how spacecraft behave in relation to the Earth's gravity, inertia and any applied forces such as the "burns" initiated by the vehicle's engines. He didn't demonstrate the "anti-normal burn" but I assume it has the opposite effect of the "normal burn leading to an inclination of the orbit." I know he's a "commercial businessman" but I would've thought Elon would be working on the "artificial gravity" aspect more than ironically "Starship." I'll admit I'm a fan of the "Star Trek" series and have always dreamed of a day when we would have some means of creating that artificial gravity environment without the need for "spinning."
@@zenithperigee7442 If you want to grasp orbital mechanics better, KSP is a really great way to do it. I highly encourage you to give it a try. I never knew anything about orbital mechanics and just tried out KSP while waiting for Starfield to released because most other space games I had already played at least a little. It was very hard to learn at first but now I can transfer to other planets and dock with other spacecraft pretty easily.
To your point about artificial gravity, I'm afraid we wont see it in our lifetime. I would even go as far as doubt it'll ever be possible. Considering most of Earth's gravity is caused by the core, you'd need either an unimaginably large craft or some kind of technology to basically break the current laws of physics. And if either of those things were possible, then you'd need some way to keep that gravity ONLY on the ship and as soon as you go out the airlock, you're in zero-G again. Otherwise, having a gravity generator that large and that close to any planets would throw off the orbit of either the planet around the sun or the moon of the planet.
Imagine an earth-sized gravity field at the altitude of the ISS. If we were on that ship and in the right spot, we could send the moon into a more elliptical orbit and either slingshot it away from Earth or closer to Earth. Plus, that gravity field could cause Earth to get pulled away from it's current orbit around the sun and have HUGE repurcussions for the entire planet. We'd be the sole reason the world ended. Kind of a cool premise to a sci-fi "end of the world" movie, though.
Fun fact that explains why Armstrong was chosen to be the first person to land on the moon; his doctoral thesis at Purdue University was titled "Lunar Orbital Mechanics". He undersood it better than anyone else on Earth.
how is it going so far? I hope you're doing well and are on track to reach your goals
Thanks! Your explanation is excellent, elegant and accurate! I tend to get technical when I explain it to non-scientific types, but Buzz (he actually changed his name) used to be called "Dr. Rendezvous" because he could figure orbital mechanics in his head, and he is one of my heroes!
That was pretty EASY to understand...and it IS rocket science. I'm impressed !!!!
Very well done! Have you considered a similar explanation for planetary slingshots? I think a lot of sci-fi writers and even news outlets get it wrong.
@photogagog, I admit I enjoy "sci-fi" but I would love a quality explanation/animation of "planetary slingshots!" IIRC this was the principle used to help the Parker Solar Probe travel towards the Sun nearing an unbelievable ~400,000 mph by the time it would reach it's orbit.
I too, would love to see that!
It seems like in a sligshot, the gravity that pulls the object in will be the same as the object leaves, so any gains in speed would be lost. The only thing that adds (or reduces depending on relative direction) is the speed of the planet's orbit around the Sun?
Oh yeeezzz! 🤓
If you think about planetary slimgshots as akin to bouncing tennis balls off moving trucks, you will only be wrong in ways that do not matter
Nice KSP tutorial
Kerbal space program players: **I AM 9 PARELLEL UNIVERSES AHEAD OF YOU**
True
One suggestion is that towards the end of the video when describing the ISS rendezvous, to start the retrograde burn from the same initial circular orbit starting condition, instead of trying to correct the previous prograde burn. That way, it will be more obvious what the two difference are and how to intercept the ISS.
I know you commented this a year ago but the point of the prograde burn was to demonstrate that with these kinds of things are not as straightforward as "accelerate towards target and you will arrive there." Like it is on Earth. He talks about how you have to slow down to go faster and speed up to slow down at a previous point in the video, so he demonstrates both. But yes, obviously a prograde burn followed by a retro burn would be significantly less fuel efficient lol.
Just a caution for those looking to understand more carefully. There is a difference between absolute velocity and angular velocity. By doing a prograde thrust to apply force you are increasing the absolute velocity of the craft and decreasing the angular velocity. Another term used in the space industry is "ground trace" that applies here. If you take a straight line from the center of the earth (this gets more complicated as the earth is an oblate spheroid rather than spherical, but that is another topic) to the spacecraft at any given instant the point on the ground (earth's surface) that intersects this line will "appear" to speed up or slow down relative to time. This is a depiction of angular velocity. By increasing the area of the ellipse, the spacecraft must increase absolute velocity, which will expand its total distance from the earth short of escape velocity. In other words, prograde will always increase absolute velocity and decrease angular velocity (even if it does reach escape velocity--i.e. no longer in orbit) and, conversely, retrograde will always decrease absolute velocity and increase angular velocity (up until the point that the orbit remains outside of other physical forces--particulates of atmosphere, space junk, solar winds, and electromagnetic drag, etc.). For reference, geosynchronous and geostationary orbits are much "faster" and "higher" than other orbits, but the angular velocity is nearly zero (it appears to stand still in the sky from the ground. Much higher orbits are still possible, but they will then appear to go "backwards" (negative angular velocity). In other words, the earth's rotation will progress farther than the rotation of the satellite orbit, from an angular or ground observational perspective.
Also, just for reference, spacecraft maneuvers typically do two prograde bursts to go from one near-circular orbit to a higher, "slower" (less angular velocity/greater absolute velocity) near-circular orbit. As shown in the animation, it creates an initial highly elliptical orbit plane and then an alternative highly elliptical offset at the "highest" point above earth that "rounds" out the orbit. (There is a lot more involved in mathematics, physics, rocketry and chemistry to this than simple calculations of perfectly frictionless pool table physics, but that is the gist of it.)
Another confusing part of this is it is all relative. If you have a polar orbit (where the angle of rotation is closer to north-south orientation than equatorial orientation), the ground trace gets much different and complicates the discussion. However, similar physics is involved, but the ground trace, launch characteristics and orbital dynamics require different sets of skills and typically different teams of people.
Finally, there is a retrograde orbit which is contrary to the earth's rotation, but that is much more a theoretical concern than practical.
The only thing I would change is to show the planet inside the orbital paths rotating about its axis, showing how the suborbital position -- the Earth coordinate -- moves with respect to the orbiting body. Depending on the orbiter's inclination, the North (or South) Pole would be in the center of the spherical planet when the craft is orbiting above the Equator, but would be offset from such a vertical position when the craft is orbiting in an inclined plane relative to the Earth's equatorial plane, with an Ascending Node and a Descending Node associated with this inclined orbital path. Also, depending on the period of the orbit, there would be certain times when the craft would appear above the same point on the Earth below, say, if it orbits 16 times per sidereal day, once every 89 minutes 45.25 seconds. If a spacecraft orbiting above the Equator were to be above 0 deg N, 75 deg W at one point, then after 16 such orbits it would again be above that spot, one sidereal day later. Animating the spinning Earth -- and including a terminator, with a Day side and a Night side -- and having a red wavy line representing the Ground Track as the planet wobbles like a top, now THAT would be cool to see. Maybe a later video could depict these things . . . ? 😎
Beautiful and comprehensive explanation of difficult concepts. High-level math and physics explaned in a way a child could understand it. Very well done!
Too kind! Thnxs 🙏
really helpful if you are struggling to rendezvous while in orbit on KSP, thank you!
I'm not sleepin on that text animation at 4:59 .. that was so smooth
At least for orbital mechanics, I think Douglas Adams was right - the trick to flying is throwing yourself at the ground and missing. :D
I think he was onto something there. (One of my favorite quotes, btw lol)
I would add that when you do a normal or anti-normal burn, you also add a small bit of prograde velocity to your new orbit at the new inclination, slightly raising your apoapsis
Not if you keep your craft pointed precisely in the normal direction during the entire burn. If you park your craft in an orientation and then do a normal/antinormal burn, though, it will instantly start to have a prograde or retrograde component of the thrust vector that will increase as long as you keep firing your engines, since you will no longer be perpendicular to your orbit once you start changing its plane.
@@sciencecompliance235 It will no matter what. Depending on how long the normal/anti-normal burn is, you can get the apoapsis back to it's original altitude, but that's usually not the case
@@ImThe5thKing You need to retake orbital mechanics class and/or vector math.
Wow, this video is amazing!
Iam in my first year studying physics where we already talked a bit about orbital mechanics but this video is an absolutely gem to get a better understanding of what is really happening…
Thx for the effort, you got my sub!
Probably the best video on TH-cam I have ever seen. Amazing. Subscribed
Thank you! 🙏🏼
*_Former Boeing... your videos are well thought out, easy to understand, even for non-engineers..._*
The ISS loses altitude due to friction with Air Molecules. Even at 250 miles up, some Air Molecules remain. NASA has to change speed and direction of ISS to get it back in it's normal orbit.
*_ISS experiences 90 percent of Earth's Gravity even at 250 miles altitude..._*
Why former? Something happen there?
@@nathan2084 Thanks for comment. I got old and retired...
Thanks!
your video editing skills are incredible, what a treat to watch!
Thank you so much!!
Wow, thank you very much Sir.
Please do part 2, showing how to launch to iss, preflight path, which degrees or angle, how to calculate when to launch. Thank you. I wish to understand that.
Your channel is gold mine for a simpleton like me. Good job and keep it up.
2:56 I Calculated And The Altitude Of The Orbit Is *1/4.5 Earths,* Which Is *2834 km* Altitude, And The ISS Orbits At An Altitude Of *402 Km* Above The Earth, And The ISS Takes *90 Minutes* To Complete An Orbit, And 2834 / 402 = *7,05* Times Higher Than The ISS, And 90 Minutes x 7,05 = *634,5 Minutes,* Then The Spacecraft In The Example Has An Orbital Period Of *10,575* Hours! Which Is *2,27 Times Less* Than The *Rotational Period* Of *The Earth!*
Absolutely amazing VIDEO with beautiful visuals! LOVE IT
Thank you! Much appreciated!
most basic KSP tutorial
hahahahaha sooo true!
You're not wrong
Some people even don't get this right so well done
I’ve watched quite a few videos, each attempting to explain orbital mechanics. I kind of got what was being instructed but, not to a complete understanding. This video however, explains the concepts perfectly. Thank you!!
Exceptionally well done!
Heureka! Finally found an explanation which helped me understand this! Big thanks!!
That was brilliant, very well explained, and very informative. Thank you
Absolutely excellent, thanks for making it!
I now have more questions than I did before this video, but that's exactly what I was looking for. Thank you for this video
Great video, it is fun and really informative
GREAT graphics and explanation - thank you.
How is this guy have 42.6k subs when his vids are amazing
Thank you this helped me visualize the xyz vectors of orbits and really helped with a physics project
"Well cant you just fire your engines at earth instead of a prograde burn? Well lets do it and see what happens"
I cant stress enough how important this is and how schools should be taking notes from this guy.
This channel deserves more subscribers. What an amazing animation. Just subscribed !!!
It makes you appreciate so much more the brilliant people at NASA that calculated the Apollo missions' Earth orbits, trans-lunar and trans-earth injections, lunar orbits and lunar orbit rendezvous, all with slide rules, pencils and paper. IBM mainframes helped, of course, but the lion's share was accomplished without computers. Amazing.
Fun fact that explains why Armstrong was chosen to be the first person to land on the moon; his doctoral thesis at Purdue University was titled "Lunar Orbital Mechanics". He undersood it better than anyone else on Earth.
Ive never felt so smart.
At one point in school our teacher played this video in class.
After hours of KSP, orbital mechanica are just so simple to me, yet my entire class was completely dumbfounded that you cant just apply force in the direction you want to go.
I mean, if you're in orbit and you shine a light at the ground (at right angles to your orbit), the light will reach the ground. So at some point between rocketry speeds and the speed of light you really can just thrust where you want to go.
❤Top tier explanation.❤
KSP has taught me a lot about rendezvous and docking. This stuff is really cool.
Superb presentation! Liked & subscribed
Great explanation, and the animations are super helpful! Is this the actual procedure they use to dock with the ISS?
You explained orbital mechanics in 10 minutes that my physics teacher can't in 2 and a half hours.
I don't know your physics teacher, but this explanation is VERY basic and provides no actual equations for calculating the precise character of these effects.
The science teacher was great, but the idea wasn't quite selling to the students @@sciencecompliance235 🤣
You truly have the best graphics out there.
Most incredible explanation. 👏
Never mind I just subscribed and saw you did a video on that exact question! Good job!
0:50 best explanation ever
Kerbal Space Program taught me this, but your explanation is great too.
I'm not sure if I would have flung myself far away first or not, but for sure I would have definitely ended up a brief fiery ball of beautiful brilliance streaming somewhere over Tajikistan, or maybe Texas! Can we have a moment of silence...
While this makes a lot of sense, I still can't undestand the maneuvers in small scale, take for instance those final moments of approach with the ISS, you're 5 meters away from the station, you actually have to trust away from the station to get closer to it? Does the famous iss docking simulation is wrong on their physics? Because I managed to dock on my 1st try, and quite a few tries later, and while initially I do in fact have some weird controls, the later maneuvers are quite straigh forward, tap accelerate to go forward, tap draft in Y to move right or left...etc.
Speeding up makes you go slower overtime, you will still move wherever you burned towards. But over time, you will slow down and go higher
Very interesting, although I’m not quite ready for a job with NASA, this video gave me a better understanding of how spacecraft orbit the Earth.
Subscribed due to the nice graphics and good explanations 👏🏻👏🏻 keep it up
That means a lot! Thank you!
Fascinating! (Oh, and live long and prosper.)
Do a video on the 3 body problem.
Wow!!! Great video!!! Thank you very much.
Definitely earned the sub. Amazing visual explanation thank you 🤩
Sweet video! Just FYI, your animation actually has dragon burning the wrong way. It doesn’t use the super Draco’s for orbital maneuvering, but the Draco engines facing more towards the top of it
Wow. Great explanation and animation
simple yet effective. One small error: the spacecrafts don't rotate. They would keep the sine direction relatively to space, so they wouldn't be always heading towards their motion direction.
Spacecraft can and do rotate. How else would they rendezvous and dock? Their rotation has no effect on their velocity or orbit.
@@AsaSpadeSS i mean they do rotate, when you want them to do so, using thrusters. They don't just point forwards always, like airplanes do. An airplanes point forward because of aerodynamics, but in space there's no air. If you leave a capsule in orbit and not rotating, it will keep that direction relatively to space (not earth)
@@giovannicorso7583Aaaand if you leave a capsule in space with the correct angular velocity it will also stay that way.
There is nothing impossible about what's depicted in this animation.
@@beanieteamie7435 you can, but simply why? Making animations like such is not wrong, but makes people believe that that's how it works, while it is just a very edge case (that you just described)
In a G field you can keep attitude without thrusters. The Long-duration Exposure Facility did this.
I've flown Orbiter Sim and KSP for years, and I don't think I've ever done a radial burn (at least on purpose). They don't seem to be very useful for orbital rendezvous purposes.
manoever nodes are very useful to learn what radial in and out, and normal and anti normal burns do!
They're only useful for last minute periapsis adjustment when encountering a planet or a moon.
Radial burns are useful when you need to move your apoapsis/periapsis to match that of the object you are trying to intercept.
They're not fuel-efficient, but sometimes due to time constraints you have to do a radial burn to rendezvous with another object sooner.
Radial burns are really useful in KSP, especially when doing midcourse corrections on interplanetary transfers.
OMG! Just watched two of your videos. These are totally awesome - such a great channel!
Nice explainations and graphics.
Exactly what I needed and exactly like the title. Thank You!!
Awesome explanations.
Wow! Extremely helpful video! Thanks a lot
I think this guy is criminally underrated.
This is really well done, thanks!
Great video! Very insightful and helped me understand the physics. I am curious what software you used to animate this?
These Kerbal people... I don't live at my computer (I live in my Quest air linked to it.)
So I use my phone: _"Spaceflight Simulator"_ is a free game which doesn't collect data or have ads. You build your rocket, launch it, and try to get into an orbit. Adding thrust will change the orbital trajectory exactly like this video.
Build too big and you'll run out of fuel (and crash) or not even get off the pad.
Same if you're too small. But with enough stages and ejectable boosters you will get into LEO.
But then the goal is to manipulate that orbit into an elongated oval which crosses the moon's orbit at a point where the moon will be when you arrive.
If you prebuilt a rover you get to drive it on the moon surface. I've never managed the fuel correctly to land (and parachutes don't work on the moon for some reason).
Mostly I just end up running out of fuel and forever orbiting the sun. Maybe one day I'll make a footprint on the moon.
Who knew rocket science was so hard.
Free, data safe, and fun. In Google Play for Android.
Space flight simulator is such a good game. It is like a free 2d KSP
@@SOR-05 It sure is. Being 2D makes the learning curve very shallow. Yet it still features enough physics to be fun. It's a great way to pass time on your phone.
Thank you! Visualizing math is pretty cool.
thanks! I can now understand how to make perfect orbit in spaceflight simulator
I'd like to see a VERY slow orbital burn. Show velocity as it goes. First you slow down. Then, at some point in the orbit you gain back that speed. Then you reach the bottom with a lot more speed. To circularize you need to slow again, but the final speed required is still more than the original. Going out to a larger circle would be fun to see in tedious slow-motion too.
Great video, and great, understanderable explanation!
This was excellent 🤙
That was excellent, thank you!
at 2:34 velocity and distance at apogee is v and r. how much velocity in terms of v do you need to add more to get a circular orbit of r?
Time is your greatest enemy. You can get anywhere you want with a gravity assist. Lining those celestial bodies up to get there is the witch of the matter.
very well explained
Thank you!
amazing,keepup the space side!
It’s pretty obvious that the fine details of orbital mechanics can get really complicated. I’m a big sci-fi fan, Star Trek, Star Wars and many others, and it seems like most of them ignore this stuff. A spacecraft simply takes off from the ground and is shown simply flying out away from the planet like it’s nothing. Or, several spacecraft near a planet or shown maneuvering easily and quickly all around each other. Pretty unrealistic, but maybe someday we’ll have technology to make such things possible.
The Expanse is the only show to do this in a plausible way with engines that seem like magic in our times.
That is an extremely helpful video!
I can't wait to master the maths behind all of these. I've independently thought out the retrograde and prograde burn(I came to know the name just from this video) and also the mathematics behind it!
If you like maths I for one would love to see what difference it would make if the moon was 25% nearer.😉😱
Wait until you find out that orbits are chaotic and have no true analytical solutions. :O
This is a perfect explanation. I don't think it could be explained better. Absolutely great work!
Thank you 🙏🏼
I was thinking about this, and got this video recommended
So good! Where is the rest of this 20 part series? 😆
Srsly though: Please more of these. Hohmann transfer, actual docking maneuvers, orbital injection, all of it. pleeeeaaase 🥺
#AnimationXplaned Excellent editing. Clear explanation. I don’t believe you. I’m still going to floor it. #holdmybeer
Just play _Kerbal Space Program._ You'll learn more about orbital mechanics (albeit with simplified single-body gravity) and have fun doing it.
Great explanation
0:24 its always fascinates me
Great video. Great job.
I have a few questions when you were explaining in the beginning about kinetic energy, theirs no explanation on why the velocity decreases, and increased the way it did. can someone please help me out?
Great question, let me see if I can help you out. If you’re referring to the point on the roller coaster….when the kinetic energy is lowering, the train is increasing in altitude and therefore increasing in potential energy. It’s simply an exchange of energy. Kinetic energy lowers when the speed does because kinetic energy s calculated through multiplying the speed by mass! Hope this helps!
My favorite orbital mechanics game (Space Agency, on mobile) had it all wrong when it comes to radial burns. Now I see why my friends who are KSP nerds didn’t like it…
very underrated channel!!!!
Wonderful !❤
Awsome explanation and graphics. Briliant!!!!
I wish you add something about rich ISS or any other object in space. I mean is not like cars break and accelerate to rich others. With orbits this dont work. Bside you rich the speed of ISS if you are not in time you can caught ISS*that is why need retrograde and prograde acceleration but when?)
I would like see how to cach up the ISS and dock not just fallow it. And about launch (orbital inclination and diference betwen launch shoot and launch orbit with the same amount of fuel.(when go 90º up and nothing tangent speed))
Just perfect
@@deadkenetic2627 Glad you think so 😁
Fun fact that explains why Armstrong was chosen to be the first person to land on the moon; his doctoral thesis at Purdue University was titled "Lunar Orbital Mechanics". He undersood it better than anyone else on Earth.
Can you do a similar explanation for gravity assists?
Sure! Its done! Browse the channel!!
@@animationsxplaned8835 I shall Thanks.
@@animationsxplaned8835 Found it, and it was a great explanation.