@@RealEngineering I ALMOST disliked the video _just because of that_ . . . -> At least leave a link in the description to the Steam´s Store page of Kerbal Space Program: store.steampowered.com/app/220200/Kerbal_Space_Program/
5:44: This is so 2019: a light-sail ubered to space using a Tesla to zoom around using a mass-less particle as its "energy" source, it's genuinely incredible.
@@dannydetonator dooku, or sisko? The first, dooku, is star wars; the second, sisko, is star trek (whose episode in questions far preceeded the star wars movie in which dooku is from). Regarding the bajorans, that's a civilization/a people, from bajor, in the same star trek series as sisko is from: deep space 9
A.C.Clarke wrote "Sunjammer," a short story about a race between solar sail spacecrafts, in 1964 :) (it was republished as "the wind from the sun" in 1972)
As important as these topics are, what we really need is a video where you say Brilliant. Over and over. I swear each time I click on your vids, it’s crossed fingers, hoping they sponsored you on the video. Your accent is the best marketing they could’ve ever asked for. But love the vid too, 10/10
@@jakobfeitzinger9587 MEng aeronautics/astronautics and you get to specialise into a branch on the 3rd year so (if all goes well) it will be spacecraft engineering.
99%: Kepler space program? 1%: random stuff 0%: very educational, love it, keep making more! Come on guys what is this? He spent a 11 minute video educating us and all you care is one second of the video where he accidentally says the wrong word....
The gravity exerted by the earth and sun are not the same at Lagrange point 1. If it were, the spacecraft would continue in a straight line instead of orbiting the sun. The earths gravity effectively cancels out just enough of the suns gravity so that the spacecraft orbits the sun slower than in normally would at that distance and instead keeps the same orbital period and relative position with the earth. Easy slip up in a great video. I love all your stuff!
Did my bachelor thesis exactly on the topic of using a solar sail to move the L1 point closer to the sun. Turns out if you use a spacecraft with a reasonable amount of instruments to monitor the sun, the mass quickly becomes too large for a solar sail. To improve the warning time significantly you need to move L1 a lot closer to the sun (the fastest CMEs are traveling at 3000 km/s so you can do the math). You would need a solar sail with side lengths of 100+ meters, which obviously causes a lot of problems.
just a heads up L1 isn't where the earth and sun's gravity cancels out, it's where earth's gravity on the object cancels out enough of the sun's gravity such that the effective remaining gravity of the sun is the same as it is at earth's height. (giving your orbit the same periodicity).
I was surprised at how interesting this video is, it surpassed my expectations! It is very informative about solar sailing, and amazingly well made! Thank you!!
thats why you make it bigger, and unfold/unfurl the sail only at the point that it can get enough push to put it in a higher orbit or a hohmann orbit, then to be assisted by a radio or other array at the higher altitude on the dark side of the planet so the perigee gets raised.. middle material can be made out of a very rigid lightweight structure, possibly only when charged or when exposed to a particular type of light. outer material can be a film that can be under tension or expansion under a certain condition like how bimetal thermometers work. another layer outside that can be added to provide rigidity so the sail can be large and slightly curved to act as a reflector for astronomy, or to keep a large many km^2 sail from folding up like a broken umbrella. film relflectance tuning can make the sail so that forces and reflectance are evenly distributed with a central micro satellite weighing down the center. if you want to make some kilometer long arms to pull out the sail, supported by some guide wires to a mast on each side to get you started, go ahead. if its based off of photo-reactive expansion then it will crinkle up, reducing surface area and drag when not exposed to light. hardest part about this is the vapor deposition needed to make the thin film and the materials science for the film choice and structural elements.
I saw you in fat Tony's a month or so ago. You were telling the barber about your channel and I was in the waiting area and remembered I was subbed to you. You got a pretty fresh trim to be fair
I love tour chanel. In my school we dont care that much about space but ur chanel always stretches my mind and makes me want to pursue being an engineer
4:45 The angle of the force experienced by the sail is at right angles to the sail. The image shows the angle of the sail changing without the angle of the force following it.
@@jeffvader811 Another trick it has is that it can thrust against the orbit, which slows the spacecraft down. This means it will fall closer to the Sun. So it can achieve any orbit, even those close to the Sun.
Im pretty certain only a small portion of that light wavelength is being captured by the sail. Imagine being able to get the stronger shorter wavelengths. That is probably where the viability of this sail will be used. So just from the top of my head, I would try a lead lined sheet and see if that can stop even more of these smaller wavelengths. So just think of it as a net with smaller holes.
A denser sail material would also increase the mass of the probe, decreasing the sail's (already quite low) thrust-to-weight ratio. I'm not sure of the exact math, but I suspect it'd be difficult to break even with that tactic, considering most discussion I've seen about solar sails seems more focused on reducing weight.
@@solarshado I would take we quite a bit of math to find the energy to weight trade off with denser sails. And it there is a beneficial energy increase.
But you have to deal with the photons you have, and when the sun is the source, those are primarily in the visual range. Sure, UV and X-ray photons would transfer more momentum, but there are not many coming from the sun.
Another really cool application of solar sails is fast travel to the outer solar system, if you could make a sail thin enough so that the force of gravity from the sun equals the force of solar pressure, then any solar sail on an escape trajectory from the Earth would travel in a straight line (as gravity and light pressure both decrease by the inverse square law). This would allow you to reach somewhere like Saturn in just 1-2 years, as gravity wouldn't slow you down.
One thing I've never understood about the solar sail issue, and this could be because of ignorant enthusiasts overhyping the technology's capabilities. One substantial design requirement for anything to last in space long term is the ability to withstand high velocity impacts of very small objects. Even when you're not sitting in Low Earth Orbit, there's a fair bit of dust floating around out there - not a lot, but when a dust particle the side of the head of a pin can impact with several times the amount of energy delivered by most firearms, it doesn't take a lot to do some major damage. (As I recall the immediate assumption with the Apollo 13 explosion was such an impact and they ruled it out because there wasn't enough damage for it to be a fragment of dust, so it had to be an oxygen tank exploding...took me a bit to parse that oxygen tank explosions rate lower than dust impacts in space) Conversely, solar sails need to be quite large in surface area (increasing the odds of an impact with dust as well as the amount of collisions with photons), and quite light...which suggests that it probably lacks the required strength to withstand the impact of one of these dust particles. It strikes me that if you're using solar sails for anything ambitious enough for them to be a significant technology, like the examples given in this video, the odds of destruction by dust particle would be unacceptably high, rendering the phenomenon more an interesting curiosity that can occasionally be used for smaller scale solutions like the probe we sent to Venus and Mercury rather than the primary driving force of the vehicle. I'm probably missing something here, because minds much more knowledgeable about space exploration are putting time into developing this technology. Anyone know what I'm missing?
You are missing this: any such micrometeorite or dust particle hit would only punch through the tiny section of the sail, leaving an equivalent size small hole. That would not impact the whole sail performance or destroy the whole sail, or several of them in case of some designs. Then, with substantial increase in size of sails you remove the necessity to have that surface be completely homogenic, so it could be a web instead, not a full sail. In cases when sails would get many, many such tiny holes over a longer period of time. - we have some technology with self healing materials already, but that's not strictly necessary since you can patch or replace whole sails when the "ship" gets to its destination, just like any vehicle can get replacement parts. And then there are magnetic sails which were not even mentioned here.
@@surfacereflection8298 Ahh, right, of course. I'm used to thinking of space ships in terms of being either pressure vessels (for living quarters or storing useful gasses) or being packed with quite delicate mechanisms (satellite electronics, the service module of an Apollo craft, etc, and I'm used to thinking of sails in the literal sense, where a relatively small hole in the canvas causes a relatively large loss of efficiency because air driven sails catch the air like a parachute does. Both of which are incorrect assumptions for a solar sail.
Zubrin in the book "Exploring Space" shows a solar sail in a very close approach to the Sun could achieve a hyperbolic excess velocity approaching 1% light speed and experience 20 g acceleration. If I remember correctly beryllium was suggested as a possible material to handle the heating.
What about the debris in the space. Don't they damage the sails? Like piercing it and making tine holes which would reduce the total available area for the momentum transferring?
In the March 1964 issue of ‘Boys Life’ magazine, Arthur C.Clarke’s story ‘The Sunjammer’ was the tale of futuristic spaceship pilot John Merton, his trusty ship Diana, and an epic space race of ten ‘sunjammers’; racing pods propelled by gigantic solar sails (the pods, big enough for one man, were tethered to the huge sails by gossamer thin lines, like gigantic parachutes). Deployed to catch the sun’s rays, the race was won by the first sunjammer to drift past the moon.
It does actually. For a stationary observer this follows from the redshift due to the change in velocity caused by the reflection. It's miniscule but it's there.
If you have a sail that can hangout in one altitude above the sun it could do so in any other since gravity and intensity of sunlight both drop with the square of the distance.
"To control it's roll and stabilize its position. A huge moment that proved the viability of solar sails." -- I'm not sure if that was meant to be an engineering joke or not, but I found it hilarious
Since photons only carry mass when hit off a reflective surface... could we theoretically have a spacecraft that shoots a internal laser at a 85ish degree mirror attached ahead the nose of the craft to create slight momentum? Obviously this would be a tiny amount of energy and you would need a at least 4 mirrors shot at to create equal force forward but it should also be able to bring us to light speed as momentum isn’t lost in space? And it would be an engine that doesn’t need traditional fuel, only energy?
No need, you can just point your light source straight back and it will push your ship froward without any mirrors. Yes, in space, a flashlight is an engine. But boy, is it a crappy one... en.wikipedia.org/wiki/Photon_rocket
If they can make the sail also absorb energy(via solar energy) they can make shuttles that rellies on solar powered thrust then nuclear powered thurst once it reach a certain distance.... the possibilities are limitless... keep up making good and interesting content
Can you make a video about Silicon Carbide power devices and its uses in EVs and Industrial applications? It is one of the trending fields in power electronics right now. Would love to see you describe what SiC is capable of!
You may have made an error at 4:24-4:59. If the reaction impulse is to counter the impulse imparted to the photons, then the thrust must be perpendicular to the sail, not parallel to the light. This is fundamentally how solar sails are controlled, otherwise they would only be able to accelerate away from the sun.
Cool, could a sail be large enough to be used on a crew sized craft? To help with acceleration to Mars or further, possibly used with ion thrusters, also, does PV panels work as a sail enough to contribute at all? Great video!!
Just going to say there were some very good animations in this video I know how hard and time consuming they are and this video had textbook examples of a good animation
Maybe this might be useful in terraforming Venus as an array of sunblockers. These would also be useful as signal boosters for communicating between Earth and Mars when they are on opposite sides of the Sun.
There is no mass in a “photon” because it is just another term for the energy expelled by an electron dropping to a lower shell orbit. Hence this explains why micro waves have more energy than infrared & Xrays have greater energy than UV AND Gamma rays fate greater than Xrays. Planks h/wave length (m)
Humanunnaki - neutrons are a proton and electron held closely together by the mutual electromagnetic properties - the are both spinning toroidal opposite attracting charges and kept apart by balancing opposing magnetic fields created by the spinning charges.
I appreciate that there is an equation that describes the quantity of momentum that light transfers to an object on reflection. However, I have not been able to locate a detailed description of the interaction between photons and atoms that explains the specific mechanism of that transfer. For example, does the photon interact with the electron shells, which then interact with the nucleus? Any guidance on this would be appreciated.
Solar sails are an option for interplanetary, or even beyond, exploration. _IF_ you can be patient enough for your instrument package to get to it's destination!
Let's say you wanted to build a small ship thar could use both ion propulsion using xenon thrusters and mylar sails. Wouldn't you be able to do the opposite of the inverse square law by bringing the craft closer to the sun by slingshotting round Venus, deploying the sails as you do so, allowing more photons to bombard the sails providing more thrust for longer which would also be affected by the gravity of Venus? From there you could build up momentum till the point where the rate of photons isn't worth the bother and use the xenon thrusters to keep increasing the momentum?
They already knew that it wouldn't last in that orbit because of the drag, it's just that they couldn't get a ride share to a higher orbit, so they settled for this.
I don't think we've learned anything science-wise but that doesn't mean the same is true for the engineering part; they did prove that the ideas we have about how to make a functional solar sail actually work, without any unforeseen "gotchas". In theory, every rocket built in the last seventy years or so would work perfectly adequately - we all know how that works out in practice...
Regarding 1:23, how does tilting the spacecraft so that its panels are impacted directly by solar radiation stabilize it? Since both panels are at the same angle, the force on each panel is the same regardless of the craft's angle or angular velocity. EDIT: Never mind. I just watched the rest of the video. My guess is that the angle of the panels isn't fixed. EDIT 2: Mind even less. I hadn't noticed the animation at 1:27 on my first viewing.
@@jeric_synergy8581 -- The way he transitioned into the next topic suggested that he thought he adequately explained the subject, so I didn't expect him to give more information that would help me understand it.
Probably a bit behind since there would be a slight delay from the sensor to the computer to process that data and send the warning signal out. I'm surprised no one has mentioned this.
@@ironmike3084 Looked into it briefly. I think he must have meant an early warning system for coronal mass ejections which apparently can accompany solar flares, but by no means always do.
Hey i have a question that is confusing me-Why don't companies like Tesla don't use small windmills in their car's back seat? This can be helpful if we add a little bit of power with a battery and when the car starts moving Then it can use fast windmill(which has an airfoil shape) to gain power???
One interesting thing about lightsail2, shadow of the earth have a con shape, so before reaching perige can catch some solar light and rise a little high of the orbit.
Why are the solar sails all folded and not rolled? Seems a sail could maintain a more perfect “mirror” surface by being a smooth roll, rather than having all the creases induced by folding. As I’m writing this, I’m thinking it has to do with an increased difficulty in deployment. The rotational mass at the beginning of the roll would be very high. If it were just unfolding, the mass of each fold is (conceivably) the same.
It was just yesterday evening that I was curious and started a research about means of space traveling along with warp engines, ion thrusters, Nasa's NEXT project.... and now this video drops!
Wait a second... I took your animation at 9:50 as being accurate. Now my homemade satellite is veering off course because venus isn't where its supposed to be! damn you!
Random thought, if the photon is imparting energy to accelerate a craft then the photon must be losing energy right? So what changes about the photon after it reflects off a solar sail? Normally it would be the speed of a object will slow but the speed of light is not going to change so what then? Wavelength perhaps?
04:52, are you sure about that? I think if it is considered the angle of the sail with the photon, it is the same if the sail is rotated or if the photon hits with some angle, it is the same angle. I could think maybe the number of photons goes with the cos and then the energy is the square of this and the cos2 appears
Lagrange point 1(L1) is the point where the sum of the gravities of the Earth and the Sun is such that it is the centripetal acceleration needed for sth to orbit the Sun at the same angular velocity as the Earth. It is not the point where Earth`s gravity is equal to that of the Sun
Here's something neat: the sun's gravity and light are both inverse squares, so a large enough sail could stay static relative to the sun, regardless of distance.
So did i miss something? If you get a photon reflecting off a mirror (imparting momentum), does the photon then travel the opposite direction at the speed of light? Or is it something with about the wave-particle duality, maybe the amplitude is reduced or something? Otherwise, you are kind of getting infinite momentum, if nothing vanishes. Eg, if you have 2 perfect parallel mirrors, you can bounce a photon between them and it would impart momentum many times as it bounces.
Nope didn't miss anything, all photons reflected have decreased wavelength then original, which also means less energy (energy conservation). If you still don't get something, consider photon have lot more energy/momentum then anything you know. To be precise that ratio would equal to speed of light. So.... Yaahh no physics laws are broken.
Shorter wavelengths have more momentum? Longer wavelengths like sound/vibration have much more push, but slower velocity, but do they work in a vacuum?
Momentum of a photon is proportional to its energy, the energy is proportional to its frequency, because they always travel at c the frequency is inversely proportional to it's wavelength. Think , Radio photon = tiny energy = abysmal momentum Infrared photon = small energy = small momentum Visible photon = decent energy = decent momentum Xray photon = crazy energy = crazy momentum Gamma ray photon = off the charts
I have always wondered how you create your animations and drawings with the blue background. It looks so professional. Do you use some specific program or a program like photoshop?
Ok so if a photon can push a satellite or destabilize a satellites orbit by hitting the object. And a reflective surface can amplify this effect. Does this mean an all glass satellite could be mostly unaffected or minimize the effect of the solar winds? Or would the photons still interact with it?
Isaac Arthur suggested that we might establish an electromagnet and focusing lens in Mars' L1 in his Terraforming Mars episode and I've been wondering if we could do something similar in Earth's L1 to mitigate the damage of solar flares. Or am I miss understanding something fundamental?
Would it be viable to push the light-sails from Earth (or Earth's orbit), with lasers ofthe most energetic wavelengths, therefore preventing the loss of energy with the distance? This system also allows for evolution of the propulsion system as we discover more effective energy sources (e.g. fusion).
From MIT: a highly acclaimed educational institute produced a roll to roll graphene on copper substrate process!!! There's your graphene and energy production that you smart intelligent scholars can cut and paste together your solar sails!! A roll to roll to solar sails from MIT!
10:11 Who's not excited for the upcoming Kepler Space Program!
Wooooopsies
More like Kerbal space program
Refracting telescopes and math!
@@RealEngineering I ALMOST disliked the video _just because of that_ . . .
-> At least leave a link in the description to the Steam´s Store page of Kerbal Space Program:
store.steampowered.com/app/220200/Kerbal_Space_Program/
I'm the king of my own land facing tempest if dust I'll fight until the end
It's pretty wild how old-school sailing is actually applicable in space.
Ha, true
It gets even wilder when you realize that role of water in that sailing analogy is played by space-time curvature, and your entire craft is the keel.
@@konstantinkh bruh. Maybe thousands of years in the future, we will see this as primitive. Like how we saw sailing ships of old now.
Space pirates !
I learned solar sailing from zula patrol.
5:44: This is so 2019: a light-sail ubered to space using a Tesla to zoom around using a mass-less particle as its "energy" source, it's genuinely incredible.
We need to talk about your crack problem, have a seat.
never forget that count doku had this before it was cool
Just aboutta say this haha
Dooku has nothing on Benjamin Sisko
@@xdproductions3087 omg I had forgot on that the bajorans have solar sailers
Is this an anime reference plz?
@@dannydetonator dooku, or sisko?
The first, dooku, is star wars;
the second, sisko, is star trek (whose episode in questions far preceeded the star wars movie in which dooku is from).
Regarding the bajorans, that's a civilization/a people, from bajor, in the same star trek series as sisko is from: deep space 9
A.C.Clarke wrote "Sunjammer," a short story about a race between solar sail spacecrafts, in 1964 :) (it was republished as "the wind from the sun" in 1972)
Read it in summer of 1964, in "Boy's Life" - I was 10. I made a model for the science fair at school. Hee-hee.
@@trishsoha 💪Why don't we see girls like you anymore among millenials?
@@dannydetonator probably because we pretend to be men on the internet to avoid unwanted attention.
As important as these topics are, what we really need is a video where you say Brilliant. Over and over. I swear each time I click on your vids, it’s crossed fingers, hoping they sponsored you on the video. Your accent is the best marketing they could’ve ever asked for.
But love the vid too, 10/10
In going to be doing aero/astronautics at uni with spacecraft engineering focus. Hopefully one day I'll be on the team for stuff like this.
Money Mule Me too! I start in a week :)
@@Devost01 same, well, the course starts October but freshers is next week lol
Money Mule have fun! My freshers is the same week as yours then :)
Is "aero/astronautics with spacecraft engeneering focus" the official name of your course?
@@jakobfeitzinger9587 MEng aeronautics/astronautics and you get to specialise into a branch on the 3rd year so (if all goes well) it will be spacecraft engineering.
10:11 Oops, I'm sure you meant Kerbal Space Program.
@Hernando Malinche no he meant I'm Gonna Fail This Launch With an Explosion Space program
Hernando Malinche r/woosh
@@MrMyTrololo r/woooosh
@@RandomPerson-jo7cw I think you mean Rapid Unscheduled Disasembally.
@@MrMyTrololo r/woooosh
99%: Kepler space program?
1%: random stuff
0%: very educational, love it, keep making more!
Come on guys what is this? He spent a 11 minute video educating us and all you care is one second of the video where he accidentally says the wrong word....
He said the word wrong though
Yes.
at least it shows commentors waited til almost the end of the video before commenting
Most people are joking man
White knight detected.
Need to understand orbital mechanics? I play KSP, I’ll be fine.
You also play Kepler Space Program? Awsome!
Try not to mess up your staging irl
Tubi movies
Or solar movies. Please.
Fantasy Island.
The gravity exerted by the earth and sun are not the same at Lagrange point 1. If it were, the spacecraft would continue in a straight line instead of orbiting the sun. The earths gravity effectively cancels out just enough of the suns gravity so that the spacecraft orbits the sun slower than in normally would at that distance and instead keeps the same orbital period and relative position with the earth.
Easy slip up in a great video. I love all your stuff!
Cringey as. Thanks for the clarification
That's an interesting subtlety. It's sort of a moot point, though, since it's an unstable equilibrium, anyway.
That is a very often overlooked detail indeed.
' slip up ' come on man, take your inane pedantic information elsewhere.
@@benejeneb You do understand people make mistakes, and its allways nice when someone points them out in a nice way like this. You are just arrogant.
Finally bit the bullet and got year on Brilliant thanks to real engineering. Enjoying it immensely so thanks for 20% off
It’s great to see some serious work on solar sailing. And kudos on another brilliant video!
Did my bachelor thesis exactly on the topic of using a solar sail to move the L1 point closer to the sun. Turns out if you use a spacecraft with a reasonable amount of instruments to monitor the sun, the mass quickly becomes too large for a solar sail. To improve the warning time significantly you need to move L1 a lot closer to the sun (the fastest CMEs are traveling at 3000 km/s so you can do the math). You would need a solar sail with side lengths of 100+ meters, which obviously causes a lot of problems.
just a heads up L1 isn't where the earth and sun's gravity cancels out, it's where earth's gravity on the object cancels out enough of the sun's gravity such that the effective remaining gravity of the sun is the same as it is at earth's height. (giving your orbit the same periodicity).
I was surprised at how interesting this video is, it surpassed my expectations! It is very informative about solar sailing, and amazingly well made! Thank you!!
thats why you make it bigger, and unfold/unfurl the sail only at the point that it can get enough push to put it in a higher orbit or a hohmann orbit, then to be assisted by a radio or other array at the higher altitude on the dark side of the planet so the perigee gets raised..
middle material can be made out of a very rigid lightweight structure, possibly only when charged or when exposed to a particular type of light. outer material can be a film that can be under tension or expansion under a certain condition like how bimetal thermometers work. another layer outside that can be added to provide rigidity so the sail can be large and slightly curved to act as a reflector for astronomy, or to keep a large many km^2 sail from folding up like a broken umbrella. film relflectance tuning can make the sail so that forces and reflectance are evenly distributed with a central micro satellite weighing down the center.
if you want to make some kilometer long arms to pull out the sail, supported by some guide wires to a mast on each side to get you started, go ahead. if its based off of photo-reactive expansion then it will crinkle up, reducing surface area and drag when not exposed to light.
hardest part about this is the vapor deposition needed to make the thin film and the materials science for the film choice and structural elements.
I saw you in fat Tony's a month or so ago. You were telling the barber about your channel and I was in the waiting area and remembered I was subbed to you. You got a pretty fresh trim to be fair
Kepler space program?
Sacrilegious
Is he trolling? He means ksp right? Kerbal?
@@Killadog1980 probably fumbled his words
@@Killadog1980 pretty sure he just miss spoke.
yeah, the game where you control a scientist from the 17th century
I'm hyped for Keplar Space Program!!!
I love tour chanel. In my school we dont care that much about space but ur chanel always stretches my mind and makes me want to pursue being an engineer
4:45 The angle of the force experienced by the sail is at right angles to the sail. The image shows the angle of the sail changing without the angle of the force following it.
Yeah, I noticed that too. This should get edited or be mentioned in the description, because it might confuse some people.
That's what I thought, to my knowledge solar sails can thrust in any direction that's not towards the sun.
Thank you! I was about to leave a comment expressing my confusion over that.
@@jeffvader811 Another trick it has is that it can thrust against the orbit, which slows the spacecraft down. This means it will fall closer to the Sun. So it can achieve any orbit, even those close to the Sun.
The advantage with ur vids is that i'm working my english and my science at the same time, keep it UP !
If only it ran on toxic pedantry from YT comments, we'd be colonizing Saturn's moons.
Ahhhhhhhhhhhhh!!!! This dude! He's insane!
"...Or you can dispense with the useless analogies and think of it as a photon bouncing off a mirror..."
Thanks so much I hate obfuscatory analogies
Im pretty certain only a small portion of that light wavelength is being captured by the sail. Imagine being able to get the stronger shorter wavelengths. That is probably where the viability of this sail will be used. So just from the top of my head, I would try a lead lined sheet and see if that can stop even more of these smaller wavelengths. So just think of it as a net with smaller holes.
A denser sail material would also increase the mass of the probe, decreasing the sail's (already quite low) thrust-to-weight ratio. I'm not sure of the exact math, but I suspect it'd be difficult to break even with that tactic, considering most discussion I've seen about solar sails seems more focused on reducing weight.
@@solarshado I would take we quite a bit of math to find the energy to weight trade off with denser sails. And it there is a beneficial energy increase.
But you have to deal with the photons you have, and when the sun is the source, those are primarily in the visual range. Sure, UV and X-ray photons would transfer more momentum, but there are not many coming from the sun.
My first real engineering after starting engineering!!!
Another really cool application of solar sails is fast travel to the outer solar system, if you could make a sail thin enough so that the force of gravity from the sun equals the force of solar pressure, then any solar sail on an escape trajectory from the Earth would travel in a straight line (as gravity and light pressure both decrease by the inverse square law). This would allow you to reach somewhere like Saturn in just 1-2 years, as gravity wouldn't slow you down.
One thing I've never understood about the solar sail issue, and this could be because of ignorant enthusiasts overhyping the technology's capabilities.
One substantial design requirement for anything to last in space long term is the ability to withstand high velocity impacts of very small objects. Even when you're not sitting in Low Earth Orbit, there's a fair bit of dust floating around out there - not a lot, but when a dust particle the side of the head of a pin can impact with several times the amount of energy delivered by most firearms, it doesn't take a lot to do some major damage. (As I recall the immediate assumption with the Apollo 13 explosion was such an impact and they ruled it out because there wasn't enough damage for it to be a fragment of dust, so it had to be an oxygen tank exploding...took me a bit to parse that oxygen tank explosions rate lower than dust impacts in space)
Conversely, solar sails need to be quite large in surface area (increasing the odds of an impact with dust as well as the amount of collisions with photons), and quite light...which suggests that it probably lacks the required strength to withstand the impact of one of these dust particles.
It strikes me that if you're using solar sails for anything ambitious enough for them to be a significant technology, like the examples given in this video, the odds of destruction by dust particle would be unacceptably high, rendering the phenomenon more an interesting curiosity that can occasionally be used for smaller scale solutions like the probe we sent to Venus and Mercury rather than the primary driving force of the vehicle.
I'm probably missing something here, because minds much more knowledgeable about space exploration are putting time into developing this technology. Anyone know what I'm missing?
You are missing this: any such micrometeorite or dust particle hit would only punch through the tiny section of the sail, leaving an equivalent size small hole. That would not impact the whole sail performance or destroy the whole sail, or several of them in case of some designs. Then, with substantial increase in size of sails you remove the necessity to have that surface be completely homogenic, so it could be a web instead, not a full sail. In cases when sails would get many, many such tiny holes over a longer period of time. - we have some technology with self healing materials already, but that's not strictly necessary since you can patch or replace whole sails when the "ship" gets to its destination, just like any vehicle can get replacement parts. And then there are magnetic sails which were not even mentioned here.
@@surfacereflection8298 Ahh, right, of course. I'm used to thinking of space ships in terms of being either pressure vessels (for living quarters or storing useful gasses) or being packed with quite delicate mechanisms (satellite electronics, the service module of an Apollo craft, etc, and I'm used to thinking of sails in the literal sense, where a relatively small hole in the canvas causes a relatively large loss of efficiency because air driven sails catch the air like a parachute does. Both of which are incorrect assumptions for a solar sail.
@@rashkavar Correct.
Zubrin in the book "Exploring Space" shows a solar sail in a very close approach to the Sun could achieve a hyperbolic excess velocity approaching 1% light speed and experience 20 g acceleration. If I remember correctly beryllium was suggested as a possible material to handle the heating.
I was waiting for this video from June!! Glad it's finally here!. Great job once again
8:00 Mariner showed that sunlight can be used for orientation. Lightsail showed it can be used as thrust.
Then could a lightsail be capable of decelerating an interstellar starship into orbit around another solar system?
What about the debris in the space. Don't they damage the sails? Like piercing it and making tine holes which would reduce the total available area for the momentum transferring?
In the March 1964 issue of ‘Boys Life’ magazine, Arthur C.Clarke’s story ‘The Sunjammer’ was the tale of futuristic spaceship pilot John Merton, his trusty ship Diana, and an epic space race of ten ‘sunjammers’; racing pods propelled by gigantic solar sails (the pods, big enough for one man, were tethered to the huge sails by gossamer thin lines, like gigantic parachutes). Deployed to catch the sun’s rays, the race was won by the first sunjammer to drift past the moon.
Thoughtful presentation. Well done.
If some of the photon's energy is transferred to the sail, does the reflected photon have a slightly longer wavelength?
Hmmm i assume yes but i dont know maybe some thing else
It does actually. For a stationary observer this follows from the redshift due to the change in velocity caused by the reflection. It's miniscule but it's there.
Thanks for using my song “Forgotten Years”! I watch your videos all the time :)
Really, cool. Do you make (any) living out of composing?
@@dannydetonator Full-time! Always glad when new people follow along
If you have a sail that can hangout in one altitude above the sun it could do so in any other since gravity and intensity of sunlight both drop with the square of the distance.
"To control it's roll and stabilize its position. A huge moment that proved the viability of solar sails." -- I'm not sure if that was meant to be an engineering joke or not, but I found it hilarious
Congrats on 2 million subs
The solar sail technology was SUCCESSFULLY used for the mars orbiter mission conducted by the Indian space research organisation (ISRO) IN 2014
Since photons only carry mass when hit off a reflective surface... could we theoretically have a spacecraft that shoots a internal laser at a 85ish degree mirror attached ahead the nose of the craft to create slight momentum? Obviously this would be a tiny amount of energy and you would need a at least 4 mirrors shot at to create equal force forward but it should also be able to bring us to light speed as momentum isn’t lost in space? And it would be an engine that doesn’t need traditional fuel, only energy?
No need, you can just point your light source straight back and it will push your ship froward without any mirrors. Yes, in space, a flashlight is an engine. But boy, is it a crappy one... en.wikipedia.org/wiki/Photon_rocket
Nice video!!! RESPECT!!!
Real engineering please do a video about f-104.
MiG-21 is better😜
PFFT, GOLDFINCH!
MiG 21 gang
@@martijn9568 doubt it
F-100
I built the F-104 in KSP, very jumpy plane
If they can make the sail also absorb energy(via solar energy) they can make shuttles that rellies on solar powered thrust then nuclear powered thurst once it reach a certain distance.... the possibilities are limitless... keep up making good and interesting content
solar powered thrust seems not viable for heavy spacecraft like shuttle
@@ssd21345 well then lets wait and hope that in the near future... it can happen like time and time again the impossible is possible
Seriously.... Kepler Space Program? Great video, I demand more!
I'd be very interested in a video on how we could prepare or mitigate the effects of a large solar event! 2 hours doesn't seem like much time
Can you make a video about Silicon Carbide power devices and its uses in EVs and Industrial applications? It is one of the trending fields in power electronics right now. Would love to see you describe what SiC is capable of!
@realengineering Congrats on the 2M subscribers!
You may have made an error at 4:24-4:59. If the reaction impulse is to counter the impulse imparted to the photons, then the thrust must be perpendicular to the sail, not parallel to the light. This is fundamentally how solar sails are controlled, otherwise they would only be able to accelerate away from the sun.
Cool, could a sail be large enough to be used on a crew sized craft? To help with acceleration to Mars or further, possibly used with ion thrusters, also, does PV panels work as a sail enough to contribute at all? Great video!!
Excellent work 👍
Just going to say there were some very good animations in this video
I know how hard and time consuming they are and this video had textbook examples of a good animation
Maybe this might be useful in terraforming Venus as an array of sunblockers. These would also be useful as signal boosters for communicating between Earth and Mars when they are on opposite sides of the Sun.
Thanks you brilliant for making this show possible
i herd "ksp" and searched to find if they are making another ksp, and they are. WOOOOOOOOOOOOOO!
There is no mass in a “photon” because it is just another term for the energy expelled by an electron dropping to a lower shell orbit. Hence this explains why micro waves have more energy than infrared & Xrays have greater energy than UV AND Gamma rays fate greater than Xrays. Planks h/wave length (m)
Humanunnaki - neutrons are a proton and electron held closely together by the mutual electromagnetic properties - the are both spinning toroidal opposite attracting charges and kept apart by balancing opposing magnetic fields created by the spinning charges.
Humanunnaki any effects discovered when these particles are blasted apart are just different electrodynamic consequences of the event
Thank you so much for another stunning video. I only understand half of it but I absolutely love it. MORE MORE MORE
I appreciate that there is an equation that describes the quantity of momentum that light transfers to an object on reflection. However, I have not been able to locate a detailed description of the interaction between photons and atoms that explains the specific mechanism of that transfer. For example, does the photon interact with the electron shells, which then interact with the nucleus? Any guidance on this would be appreciated.
I remember reading a science fiction story many years ago about solar sailing. Photons for the win!
Solar sails are an option for interplanetary, or even beyond, exploration. _IF_ you can be patient enough for your instrument package to get to it's destination!
So light is a solid!
10:09 Smoothest fucking Ad read/transition in human history.
Good day,Everybody
i just want to say that i really enjoy watching these videos
Can't wait for KSP2!!!
Let's say you wanted to build a small ship thar could use both ion propulsion using xenon thrusters and mylar sails. Wouldn't you be able to do the opposite of the inverse square law by bringing the craft closer to the sun by slingshotting round Venus, deploying the sails as you do so, allowing more photons to bombard the sails providing more thrust for longer which would also be affected by the gravity of Venus? From there you could build up momentum till the point where the rate of photons isn't worth the bother and use the xenon thrusters to keep increasing the momentum?
Aw, he brought that up lol
I remember the movie AVATAR where the ship ISV venture star uses a solar sail to travel from Earth to Pandora. It was cool
We can't really say the program was a waste, because we still learned that it's impractical to have a solar sail at that height.
They already knew that it wouldn't last in that orbit because of the drag, it's just that they couldn't get a ride share to a higher orbit, so they settled for this.
No, not really. We could've figured that out through simple calculations.
I don't think we've learned anything science-wise but that doesn't mean the same is true for the engineering part; they did prove that the ideas we have about how to make a functional solar sail actually work, without any unforeseen "gotchas". In theory, every rocket built in the last seventy years or so would work perfectly adequately - we all know how that works out in practice...
2:42 nit picking here but use sN instead of kgm/s. As you said a photon is massless therefore using that scalar doesn't make sense.
Third year orbital mechanics class I took 3 years ago is actually helping me understand a youtube video Ha!
Regarding 1:23, how does tilting the spacecraft so that its panels are impacted directly by solar radiation stabilize it? Since both panels are at the same angle, the force on each panel is the same regardless of the craft's angle or angular velocity.
EDIT: Never mind. I just watched the rest of the video. My guess is that the angle of the panels isn't fixed.
EDIT 2: Mind even less. I hadn't noticed the animation at 1:27 on my first viewing.
Maybe you should consider ALWAYS watching all the way thru before firing up the comment mill.
@@jeric_synergy8581 -- The way he transitioned into the next topic suggested that he thought he adequately explained the subject, so I didn't expect him to give more information that would help me understand it.
How would the solar fair warning system work? How would the warning arrive before the effects of the flair?
How would an early warning system for solar flares work? Wouldn't they travel at light speed right along with any warning about them?
Probably a bit behind since there would be a slight delay from the sensor to the computer to process that data and send the warning signal out. I'm surprised no one has mentioned this.
@@ironmike3084 Looked into it briefly. I think he must have meant an early warning system for coronal mass ejections which apparently can accompany solar flares, but by no means always do.
Hey i have a question that is confusing me-Why don't companies like Tesla don't use small windmills in their car's back seat? This can be helpful if we add a little bit of power with a battery and when the car starts moving Then it can use fast windmill(which has an airfoil shape) to gain power???
Drag. Requiring more power to move that car the faster the car goes. More so than can be regained by a small windmill.
It just wastes a ton of energy.
One interesting thing about lightsail2, shadow of the earth have a con shape, so before reaching perige can catch some solar light and rise a little high of the orbit.
Why are the solar sails all folded and not rolled? Seems a sail could maintain a more perfect “mirror” surface by being a smooth roll, rather than having all the creases induced by folding. As I’m writing this, I’m thinking it has to do with an increased difficulty in deployment. The rotational mass at the beginning of the roll would be very high. If it were just unfolding, the mass of each fold is (conceivably) the same.
It was just yesterday evening that I was curious and started a research about means of space traveling along with warp engines, ion thrusters, Nasa's NEXT project.... and now this video drops!
Wait a second... I took your animation at 9:50 as being accurate. Now my homemade satellite is veering off course because venus isn't where its supposed to be! damn you!
When you showed a clip from the ksp2 trailer I half expected to hear, "This video is sponsored by Private Division"
Shouldn't the drag at perigee cause apogee to be lowered? That is sort of what I would expect from Kerbal Space Program
Random thought, if the photon is imparting energy to accelerate a craft then the photon must be losing energy right? So what changes about the photon after it reflects off a solar sail? Normally it would be the speed of a object will slow but the speed of light is not going to change so what then? Wavelength perhaps?
Nice video and keep it up!!
Technological a great project to determine technological transmission for phones etc . perhaps, thank you for explanation.
04:52, are you sure about that? I think if it is considered the angle of the sail with the photon, it is the same if the sail is rotated or if the photon hits with some angle, it is the same angle. I could think maybe the number of photons goes with the cos and then the energy is the square of this and the cos2 appears
Lagrange point 1(L1) is the point where the sum of the gravities of the Earth and the Sun is such that it is the centripetal acceleration needed for sth to orbit the Sun at the same angular velocity as the Earth. It is not the point where Earth`s gravity is equal to that of the Sun
Here's something neat: the sun's gravity and light are both inverse squares, so a large enough sail could stay static relative to the sun, regardless of distance.
I’m more of a fan of the Keebler Space Program. Little elves solar-sailing cookies
So did i miss something? If you get a photon reflecting off a mirror (imparting momentum), does the photon then travel the opposite direction at the speed of light? Or is it something with about the wave-particle duality, maybe the amplitude is reduced or something? Otherwise, you are kind of getting infinite momentum, if nothing vanishes. Eg, if you have 2 perfect parallel mirrors, you can bounce a photon between them and it would impart momentum many times as it bounces.
Nope didn't miss anything, all photons reflected have decreased wavelength then original, which also means less energy (energy conservation). If you still don't get something, consider photon have lot more energy/momentum then anything you know. To be precise that ratio would equal to speed of light. So.... Yaahh no physics laws are broken.
Baby steps, you gotta walk on sunshine before you can sail!
Shorter wavelengths have more momentum?
Longer wavelengths like sound/vibration have much more push, but slower velocity, but do they work in a vacuum?
Roger C think xrays and gamma rays which are shorter wavelengths have more momentum
Nothing travels faster than light, many hot things thrust.
Momentum of a photon is proportional to its energy, the energy is proportional to its frequency, because they always travel at c the frequency is inversely proportional to it's wavelength.
Think ,
Radio photon = tiny energy = abysmal momentum
Infrared photon = small energy = small momentum
Visible photon = decent energy = decent momentum
Xray photon = crazy energy = crazy momentum
Gamma ray photon = off the charts
I have always wondered how you create your animations and drawings with the blue background. It looks so professional. Do you use some specific program or a program like photoshop?
Ok so if a photon can push a satellite or destabilize a satellites orbit by hitting the object. And a reflective surface can amplify this effect. Does this mean an all glass satellite could be mostly unaffected or minimize the effect of the solar winds? Or would the photons still interact with it?
3:48 has anybody else also noticed the optical illusion? The squarses in the right most surface look smaller then the first one 🤔
KSP 2 animation at 10:11, can't wait for it to release.
Isaac Arthur suggested that we might establish an electromagnet and focusing lens in Mars' L1 in his Terraforming Mars episode and I've been wondering if we could do something similar in Earth's L1 to mitigate the damage of solar flares. Or am I miss understanding something fundamental?
Would it be viable to push the light-sails from Earth (or Earth's orbit), with lasers ofthe most energetic wavelengths, therefore preventing the loss of energy with the distance? This system also allows for evolution of the propulsion system as we discover more effective energy sources (e.g. fusion).
Excellent episode, thank you!
Great stuff! keep it coming.
From MIT: a highly acclaimed educational institute produced a roll to roll graphene on copper substrate process!!! There's your graphene and energy production that you smart intelligent scholars can cut and paste together your solar sails!! A roll to roll to solar sails from MIT!
No mention of the Japan Space Agency's Ikaros spacecraft which arguably accomplished more than Lightsail?
8:07 Takes place at Cal Poly San Luis Obispo (where I currently go)...Crazy!