_"If you want to get into the details, get a Physics degree"_ is something that more people on youtube should have the courage to say. Not everything can be explained properly in a 15min video to someone who doesn't have the prerequisite knowledge. And completely ignoring my own advice, I'll add that photovoltaic cells are LEDs in reverse operation. That description works on far more levels than it has any right to.
Call be jaded but a physics degree doesn't teach you anything. They just provide the tests, it's up to you to teach yourself. I would have been better off giving my 30 grand to scott's patreon tbh
I worked in a micro technology lab for a year and when I first arrived they got me to make a simple solar panel to get me familiar with the machines and methodology. At some point someone mentioned that photovoltaic cells and LEDs were the same thing and then proved it to me by reversing the battery my panel was charging and showing it through a camera that could pick up the light. It was absolutely mind blowing and really got my mind thinking of just how simple yet versatile circuits on silicon really were.
The really cool thing about solar panels since they are reverse LEDs is that they also can act as normal LEDs when forward biased. Not much out of them clearly, but enough to be able to detect micro fragments in the solar cells. Cool when I saw it.
@@impguardwarhamer yes, if you just sit there and expect to passively learn stuff your not gonna get much out of university. A university is a place that will provide a structured learning environment (take class A, then class B, then class C), but that's not going to work for everyone. No matter how you want to learn (via school, or self taught) you need to be an active participate in your own education.
I find it fantastic that AMSAT failed itself to a functional status. It is the kind of event that a fiction writer would likely not have imagined before it happened.
""Failed into a functional state""?? ... Or repaired thanks to a _sentient being,_ which then took the necessary steps to rectify its fault?? 😲😁 I'd like to think it was a tardigrade that managed to develop electrical engineering skills! 🤣 If anything *could* pull it off, it'd be one of those little badasses... I mean, or an Octopus, given they already ARE intelligent as hell! But that's an _even more_ absurd notion than a tardigrade... lmao **now starts imagining an octopus in a tiny, bespoke spacesuit........ 🤔**
I didn't expect this series to come back, but glad that it did. I always wondered how Solar panels worked, especially on smaller things like probes, thank you
I previously worked on multi-junction cells. I'm quite impressed about the job you did outside your formal training! My only minor nitpick would be that the battery didn't short circuit with AMSAT. It finally went open circuit so the failed battery was no longer pulling the voltage down.
It's kind of amazing though. 1974: launch 1981: battery failed, pulling down power, rendering satellite inoperable 2002: battery failed further, no longer hindering power of the satellite, rendering satellite semi-operable again
@@timboatfield AMSAT-OSCAR 7 flew with NiCad batteries. These have a finite lifetime of charge/discharge cycles. The usual failure mode after many charge cycles is the growth of "whiskers" between the plates of the batteries. Eventually, these short the positive/negative electrodes and the battery can no longer take or hold a charge. The theory is that as the solar panels continued to dump energy into the batteries, eventually the current through those whiskers caused them to melt? or at least go open. At that point the battery was no longer drawing the power bus down and adequate voltage was available to power the spacecraft systems. I've experienced this failure mode myself with more mundane terrestrial radios. Back in the day, hams would buy old commerical 2-way VHF/UHF radios and re-tune them to the amateur bands. I had a really great Motorola HT-220 handheld radio, and it came along with a bunch of mostly dead battery packs. The thing is, replacement batteries for these things cost a lot of money (and were not simply a bunch of AA NiCad batteries in a compartment.) And I was a poor college student. What you could do was run a heavy current through the battery, and if you got it right, you'd burn away those internal whiskers and not melt and/or blow up the battery pack. This didn't give you a as good-as-new battery, or even a so-so battery. It got you a crummy battery for "free." I think in the AMSAT-OSCAR 7 case, we got to see the "melt/blow-up" case where the battery went open due to the over-charging current over the span of a decade or two.
@@lmamakos Thanks that was interesting and a nice anecdote and finishing with a mind panting of the silent fate of the battery. Top comment. I'd suggest you make that in to a video. This comment and your last few video have already earned you a sub.
What's interesting is when you look at designs for space stations and such from the 1940s and 50s, they are depicted as having solar thermal turbine generators for power, basically a parabolic reflector focused on a boiler unit filled with liquid sodium or some other working fluid, that then heats water to turn a turbine and generator. Photoelectrics were not yet ready for prime time so designers and futurists were working with technology of the day. BTW, I have an old Minolta twin lens camera from the 50s that uses a selenium light-powered meter, no batteries required, and it still functions just fine.
There are still proposals by futurists for solar thermal power in space, but scaled up to beam down to Earth or for stations and bases with high power demands. A surface base on something like the moon or even an asteroid could use the heat directly to bake volatiles out of the ground.
Seeing this stuff about how solar cells can be extremely weak LEDs if power is put into them makes me think of how crazy it would be for someone in a fictional setting to secretly send morse via solar cells knowing an enemy is monitoring all normal RF frequencies. but only a still manned friendly science station would be monitoring near visible IR. Since I am guessing what tiny light they do give off is similar in spectrum location to a TV remote. Which digital imaging systems can see.
Solar panels are able to detect a laser pointed at it and this has been demonstrated to be capable of high bandwidth signalling. With a laser to return data, this could be both covert and almost undetectable. Starlink V3 maybe?
@@RCAvhstape or a laser for extra sneakiness. There was an experiment a while ago where some people successfully signaled the ISS with a pretty low power laser on the ground. And by signal, I mean they could see it out of the cupola window. I want to say Scott has a video on it
Arthur C Clarke's _Earthlight_ from 1955 has an astronomer spy on the moon sending messages back (to Mars) by replacing the eyepiece of a vast lunar telescope with a light source, allowing him to send very tightly focused beams of light to waiting spacecraft. This is completely not the thing being described here, but is still pretty cool.
I grew up in the 1950s and was intrigued by solar energy. They sold little hobby solar cells so you could get your hands on the process. In the 1980s I built a remote weekend house that Progressively became solar powered. I believe the U.S. Gov. Used me and the remote house in a ten years long alien exchange program. My first generator in 1985 had one experimental solar panel sold off by Motorola Government Electrics Group to employees. I ran 12 volt current into the house and I love this arrangement being so simple and fool proof and absolutely dependable. Next went to AC with a small inverter. Then jumped to 3,000 watts with a huge battery pack and three solar panels. I sold the remote house and that generator ran 12 years with no maintenance and was trouble free. Today being retired I live in a van with two inverters two battery packs and one 100 watt China manufactured solar panel. I run two 250 watt Electric heaters for winter heating, lighting, an entertainment center and a small refrigerator.
Your electric setup sounds interesting. Aliens do not care about the American government though, and don't participate in exchange programmes with native fauna 👍
@@johnn1199 Yes alien's run their own show. I was an official involved with military research and at my remote cabin I read the best research findings published at that time. It was under stood that the alien's would gather exchange information from me. I was taken to an ice planet or moon where I must have received extensive modifications. It to appeared that I was taken to earth based alien sites possibly to contribute work on projects. I developed an understanding of ancient Native American mapping and of sites globally related to my cabin site. I also can explain the structure of gravity and the nature of deep space relationships. From secure sources I was informed that I am an descendent of Christ and that I am extraordinary.
its cool when a project I worked on for my degree becomes its own youtube video. I had to write a 5 page essay on solar panel technology and you covered almost all of it in 15 minutes!
Nice explanation. Simple and tight, but PRACTICAL. I am a RF/wireless engineer and I found that what gave me the best design instincts was UNDERSTANDING THE PHYSICS.
Please Scott, could you make a video explaining and comparing the G forces suffered during launch in differents rockets across the history? Not only for humans, but also equipments. Your videos are simply the bests!! Thanks!
Thanks for this explanation! I did a physics degree but don't remember any of the bit we had on semiconductors! At least we didn't learn about how solar panels work. I only remember the name 'photo-electric effect' and not the details...! My Dad used to talk about solar cells because he was into electronics and thought he had an idea for making them more efficient, but who knows if any of his ideas were valid or might have been useful! He spent so many years frustrated and unemployed when he could have been doing some useful job somewhere if only there had been something nearby that suited his skills and knowledge. As it is he spent a lot of time reading science and computer magazines and wishing he could contribute a new idea somewhere - so eventuallty he began writing letters to 'important' people telling them how we should 'save the world'!
I used OSCAR 7 as soon as it became operational in 1974. I'm in the UK and my first contact via the satellite was on orbit 21. That was nearly 50 years ago and memories fade but I seem to recall that OSCAR 7 used early COS/MOS (later known as CMOS) logic ICs donated by RCA, the company that invented CMOS technology. The company wanted to find out how well this type of logic survived in the radiation environment of low Earth orbit. As it happens, the ICs survived much longer than RCA, which was bought by GE in 1986 and parts of the company were then sold or liquidated. RCA now exists only as a brand name but the ICs in OSCAR 7 continue to operate.
@@pegasus7607 Thank you for the back story. At a Hamfest before the virus I met the man responsible for the programing of the AO-85, AO-90, and AO-91. He was showing my daughter and I how the antennas were wrapped up with a small bit of fishing line. He told us how his program triggered a resistor to heat up and melt the line to deploy the antenna. It's a great hobby with skilled and passionate people. 73 thanks again
Hi Scott and greetings from Marburg Germany, where my father was involved in building Oscar 7 and other satellites for AMSAT - back in the days. Oscar was conceived and raised in the ZEL, Zentrales Entwicklungslabor fuer Elektronik (Central Electronics Developement Lab) a branch of Marburg's famous University. That place was Skunkworks and JPL at Christmas for me as a teenager - and maybe it actually was in deed. Thank you soo much Scott for digging this Oscar story up - I wish i could dive into that memory together with my him now. Best Regards from Marburg, near EDFN, right underneath the MARUN transition of EDDF's SID, fly save!
I'm glad you corrected the Pu-235 blooper! I worked in the facility at DOE's Savannah River Site where we processed Pu-238 and got to travel to Florida to watch Galileo launch. The cost issue with the material is we just don't have any reactors still operating where you can make much Pu-238 since the reactors at Savannah River shut down. You can make limited amounts in the HFIR at Oak Ridge or at the ATR at Idaho National Labs. But to make reasonable amounts for deep space missions, you'd need to build a new reactor, which isn't cheap, thus the 'high cost' to make Pu-238.
it always amazes me seeing these spacecrafts with people around them working with them so you can get the scale of the size of them, the size of them makes them all that more impressive...against the seemingly infinite background of space they seem tiny but some of them are huge!
LOL! "If you throw enough of these together into one place, you get a computer" had me laughing, but adding, "you managed to make rocks think" killed me! Good one, Scott! XD I'm sitting here thinking of my plans for Eve missions. ;) They'll be fine, of course, but I wonder if Realism Overhaul changes solar panels... Eh! I'm not really planning on trying it. :) AMSAT-1 amazes me! :D
Great series Scott! I heard about Boeing having problems with solar concentrators. The very thin panels had adhesives that got too hot, loosening a little, and the panels warped. Also, the relatively cold reflective film immediately condensed the outgassing material, becoming dark and not reflective. Double whammy.
Yes, it was quite a boondoggle with many of those satellites needing to be replaced ahead of schedule due to unexpectedly fast power degradation. XM Satellite Radio's first two satellites were among the victims.
Wow: well done. When you started describing the history of solar cells I was mentally lamenting the fact I can't post my photos of Fritz's New York rooftop panels in the comments - and there you are, you've got them. Well researched, sir.
amazing Juno and other probe building footage. Cool to see something on the ground in all it's impressive size, that you only know from 3d animations now.
Great to see amateur radio satellites being given a mention! They are a great way to get into orbital mechanics, space electronics and mechanics. The satellite company SSTL started out life at Surrey Uni, making amateur radio sats.
Has there been any progress in reducing the cost of multi junction solar panels for something like home PV systems? It would be nice to be able to capture more energy so that heavy usage days still leave enough power to charge your batteries.
Traditional multi junction cells use III-V compounds like GaAs, which makes them prohibitively expensive for the consumer market. However, recently there have been commercial developements to build tandem cells out of standard silicon and a new class of solar cells called perovskites, which can be produced cheaply. While this doesn't increase efficiency as much as traditional multi junction cells, it does so much more affordably.
I don't think there's much more point, since efficiency kinda is a strange thing in solar panels. With most other power sources, increasing efficiency means reducing upkeep costs as you need less fuel to do the same thing. Thing with solar panels is, efficiency is just another way of writing the power per square unit of length. So increasing efficiency at high costs just makes less sense than putting more of the things. Commercial solar panels are efficient enough to supply the house they're laid upon without exceeding the size of the roof, and for massive photovoltaic farms the real metric still is watts per dollar spent, not efficiency, because there's no point spending twice as much per solar panel for a marginal gain if you could instead just put down twice as many of the things. In a sense, multi junction solar panels can also be less efficient in a watts per kwh sense, since they take for more effort to make. Really, "efficiency" in solar panels is the conversion factor of incident light to electrical energy, which may not be the actual metric of what we would consider efficient in practise.
The cost per square cm for a GaAs triple junction cell is so much higher than si, that it will never be a real alternative for normal rooftop applications. However there are concentrator pv Moduls availible that need tracking units but can be more cost effective than si. The most advanced cells use up to 5 junctions on top of each other with an efficiency up to 46%. For example by "Azur Space Solar Power".
In the case of the Ham satellite, what mostly likely happened is this. When a battery fails, its voltage drops close to zero, but its internal resistance remains low. Time passed, and the electrolyte of the batteries evaporated completely. Therefore, the internal resistance of the batteries shoot up, to a value that is equivalent to a total disconnection. This allowed the onboard electronics to be powered directly from the solar cells.
Take a look at non-imaging photo concentrators. They have an advantage where they can accept a much broader range of incident angles. I've used similar concepts to help make uniform spots from LEDs in making basically the opposite.
Hey Scott First of all thank you for all the high quality content you have made in the last 5 years. Since you introuduced me into ksp my fascination for Space in generall, has only increased. from Spy Satalites, Cold War experiments , unintuitive Orbital Mechanics to Astroid composition, i gladly suck iit all in. One Topic which i couldnt find on your channel was the Buran Space Shuttle. I would be highly interested in your disection of this topic, since you are by far the best AstroSciencePublicComunicators out there (if that word even exsits). And Again Scott, thank you for all the effort you have put in your Videos, truly Legendary Sir!
The angular alignment for concentrating PV isn't as critical as for imaging optics, because they don't need to create a sharply focused image of the sun - they just need to smush the photon flux hitting a given area down into a given smaller area. For example, if you want a concentration factor of 10, you can using reflecting optics get an accepance angle of about 18 degrees.
Excellent video. It recalls my interest in solar energy for home use. I have looked at it continuously over the years but have not yet done anything about it. One thing that always concerned me was the technology. I would read about the newest technology then go to talk with the actual providers and the technology available was always years behind the new technology being reported. All these advances while good down the road would be better if they were available right now or interchangeable so you could take advantage of new developments right away. I am no longer in an area best suited for solar and I'm getting older. I doubt I'll ever use it myself.
Another reason PV works great in space is that PV cells are more efficient as they get colder, below 25C. So much more so that people who design PV systems have to take into account the extra voltage generated for solar installations in places where you can get very cold, very sunny days!
@@scottmanley Yeah, "cold" kind of loses its meaning in vacuum... no convection to transfer heat in and out of the system. It's all about radiative cooling... whether you can emit more heat than you're generating and receiving.
Pioneer 5 was the first solar-powered spacecraft to be launched into interplanetary space, two years before Mariner 2 did. Nevertheless, what a great video as always!
It’s only the photons with energy E = fh > band gap that supply electricity... it doesn’t matter how many photons arrived. This was the discovery of Einstein 1905 photoelectric effect.
Interesting, you implied that most solar cells in space are silicon, or perhaps multijunction. My understanding was that they were CIGS, because of the higher efficiency and because they were thin film, so could be rolled up without being damaged. I just did some poking around and couldn't find anything that confirms that. Plus your point about using small, rigid but curved silicon pieces on a flexible backer makes a lot of sense.
when i first saw the RTG in KSP, and it's.. abysmal power output, iwas like "hell nah, never going to use that" Guess who reconsidered his Gigantor Panel Design when reaching Jool 🙄
If anyone really wants to know more on how solar cells work, don't bother. Like Scott said, any more info and you may as well do a Physics degree. As someone on a Physics masters, I agree. The physics involved is complex, but a very interesting kind of complex. The kind that makes you think "who the hell even thought of this stuff". Nice vid Scott! You summed it up well!
Want to know something Cool thing about Solar cells? They're so close to being LEDs and vice versa. If you take a solar cell out of a cheap calculator and hook a power source to the cells power leads in a dark room, it'll glow ever so slightly. Same thing with LEDs, you take a simple LED, hook a voltmeter to it and expose it to the sun, you'll see a increase in electric flow.
This phenomenon is used in an electronic device called a "photodiode", also in "phototransistors" which are just photodiodes with an amplifying transistor added. They're available in packages similar to those you find LEDs in, yet they generate a voltage when exposed to light. IR LEDs and photodiodes are why most remote controls function as well as they do (granted that they modulate the signal on a roughly 40khz carrier wave, but the data is sent nonetheless.
That clip about dividing by zero. Siri answering, "Imagine you have zero cookies and you split them among zero friends." Why she gotta call me out like that?
@2:39 "...managed to make rocks think" I had an IT company in 1998 and I named it SmartStone. So glad that somebody sees that silicone in the chips is nothing else but rocks... by the way domain is still for sale. $2mln :)
polycrystalline cells can handle lower light flux than monocrystalline panels. Their maximum efficiency is lower but they are effective in dimmer conditions, one of the reasons you find them on calculators for use indoors.
You should have mentioned mercury boilers which is how they thought space stations would be powered before more efficient solar cells were developed. Reflectors focused sunlight on a tube carrying mercury that would drive a thermal engine to power the station.
Wonderful video Scott! One small thing though. You corrected yourself saying Plutonium 238. That's actually the stuff used in reactors and nuclear weapons. Pu-239 is the stuff used in RTG's. Cheers!
Very informative video✨. Also like to know more about how this solar panels helps the spacecraft to sail through space and what r other possible energy sources for spacecraft beyond solar system 🚀
Nice intro to solar cells. Just wait until you try and figure out where to point them! Most people think it’s at the sun but power, thruster plume loading, thruster plume contamination, visiting vehicle plume loading, shadowing, thermals, comm restrictions, drag reduction, risk of failure of motor drive assemblies and latching mechanisms all say otherwise.
Multijunction III-V vs silicon is actually not as simple as the efficiency number suggests. Multijunction cells use Germanium substrates that are much heavier than Si substrates. Therefore, the power-to-weight ratio of early multijunction panels are not superior to silicon panels. Multijunction cells are mostly valued for their higher radiation resistance for deep space applications. Using concentrators however changes the math since the cell mass are now a much lower part of total panel weight and multijunction panels have much smaller area and thus lighter structural support. For future spacecraft, less efficient thin film panels with much higher power-to-weight ratio are desirable. But TF cells have their own set of problems too.
I understand your alma mater is a key centre for research on momentum exchange tethers. I would very appreciate your input on the subject. I am especially interested in the interaction between momentum exchange tethers and propulsion systems that do not use reaction mass (e.g. e-sail) and variable moment of inertia tethers.
I like your videos, is there a video about the technology used by the Maxar satellites that provided the photos during this war on Ukraine: the imaging, orbit, launching vehicles, etc ... ? Thanks
_"If you want to get into the details, get a Physics degree"_ is something that more people on youtube should have the courage to say. Not everything can be explained properly in a 15min video to someone who doesn't have the prerequisite knowledge.
And completely ignoring my own advice, I'll add that photovoltaic cells are LEDs in reverse operation. That description works on far more levels than it has any right to.
Call be jaded but a physics degree doesn't teach you anything. They just provide the tests, it's up to you to teach yourself.
I would have been better off giving my 30 grand to scott's patreon tbh
@@impguardwarhamer I mean, yes, it's implied that what is really meant is _"Study Physics at a university or equivalent up to at least degree level"_
I worked in a micro technology lab for a year and when I first arrived they got me to make a simple solar panel to get me familiar with the machines and methodology. At some point someone mentioned that photovoltaic cells and LEDs were the same thing and then proved it to me by reversing the battery my panel was charging and showing it through a camera that could pick up the light. It was absolutely mind blowing and really got my mind thinking of just how simple yet versatile circuits on silicon really were.
The really cool thing about solar panels since they are reverse LEDs is that they also can act as normal LEDs when forward biased. Not much out of them clearly, but enough to be able to detect micro fragments in the solar cells. Cool when I saw it.
@@impguardwarhamer yes, if you just sit there and expect to passively learn stuff your not gonna get much out of university. A university is a place that will provide a structured learning environment (take class A, then class B, then class C), but that's not going to work for everyone. No matter how you want to learn (via school, or self taught) you need to be an active participate in your own education.
I find it fantastic that AMSAT failed itself to a functional status. It is the kind of event that a fiction writer would likely not have imagined before it happened.
It's one of those rare mutations that has a benefit. ;)
I beg to differ, it sounds like something out of an Asimov story!
""Failed into a functional state""?? ... Or repaired thanks to a _sentient being,_ which then took the necessary steps to rectify its fault?? 😲😁
I'd like to think it was a tardigrade that managed to develop electrical engineering skills! 🤣
If anything *could* pull it off, it'd be one of those little badasses... I mean, or an Octopus, given they already ARE intelligent as hell! But that's an _even more_ absurd notion than a tardigrade... lmao
**now starts imagining an octopus in a tiny, bespoke spacesuit........ 🤔**
mission failed successfully .
If someone wrote that you would then call it lazy writing!
"You have managed to make rocks think"
I don't know why, this should be obvious but when it is stated like that it is so mind blowing...
trees are made of sugar
Moon is motly made out of silocon dioxide, lets make it think :D
It's not really thinking, though. It's just cleverly switching currents as designed. Moderately impressive, but hardly mind-blowing.
Humans are just carbon and water
Humans are just carbon and water
The all loved format has returned!!!
How this comment has nearly 300 likes and no comments is beyond me.
@@jojo_da_poe I guess because it's because it was one of the first and most people focus on getting the first comment themselves
I didn't expect this series to come back, but glad that it did.
I always wondered how Solar panels worked, especially on smaller things like probes, thank you
I had no idea that solar panels... on top of _roofs_ ... were a 19th century innovation.
@@-danR Tesla wasn't the only electrical Engineer of that era, looks like a lot of bright lights bloomed alongside him.
@@linyenchin6773 lol
I previously worked on multi-junction cells. I'm quite impressed about the job you did outside your formal training!
My only minor nitpick would be that the battery didn't short circuit with AMSAT. It finally went open circuit so the failed battery was no longer pulling the voltage down.
Beat me to it.
I was thinking the same thing! Lol
I spotted that too, and I know very little about this except I paused the video and read the AMSAT posting shown.
It's kind of amazing though.
1974: launch
1981: battery failed, pulling down power, rendering satellite inoperable
2002: battery failed further, no longer hindering power of the satellite, rendering satellite semi-operable again
There is something beautiful about amsat's battery failing so completely that it started working again.
Totally! A deeper dive into what and how is suspected to happen would be fun and interesting. *@ Mr Manley ?*
@@timboatfield AMSAT-OSCAR 7 flew with NiCad batteries. These have a finite lifetime of charge/discharge cycles. The usual failure mode after many charge cycles is the growth of "whiskers" between the plates of the batteries. Eventually, these short the positive/negative electrodes and the battery can no longer take or hold a charge.
The theory is that as the solar panels continued to dump energy into the batteries, eventually the current through those whiskers caused them to melt? or at least go open. At that point the battery was no longer drawing the power bus down and adequate voltage was available to power the spacecraft systems.
I've experienced this failure mode myself with more mundane terrestrial radios. Back in the day, hams would buy old commerical 2-way VHF/UHF radios and re-tune them to the amateur bands. I had a really great Motorola HT-220 handheld radio, and it came along with a bunch of mostly dead battery packs. The thing is, replacement batteries for these things cost a lot of money (and were not simply a bunch of AA NiCad batteries in a compartment.) And I was a poor college student. What you could do was run a heavy current through the battery, and if you got it right, you'd burn away those internal whiskers and not melt and/or blow up the battery pack. This didn't give you a as good-as-new battery, or even a so-so battery. It got you a crummy battery for "free."
I think in the AMSAT-OSCAR 7 case, we got to see the "melt/blow-up" case where the battery went open due to the over-charging current over the span of a decade or two.
@@lmamakos Thanks that was interesting and a nice anecdote and finishing with a mind panting of the silent fate of the battery. Top comment. I'd suggest you make that in to a video. This comment and your last few video have already earned you a sub.
I like to believe that Scott came across that little tit bit, and then scripted the whole video just to get to that point at the end.
The mission failed successfully.
What's interesting is when you look at designs for space stations and such from the 1940s and 50s, they are depicted as having solar thermal turbine generators for power, basically a parabolic reflector focused on a boiler unit filled with liquid sodium or some other working fluid, that then heats water to turn a turbine and generator. Photoelectrics were not yet ready for prime time so designers and futurists were working with technology of the day.
BTW, I have an old Minolta twin lens camera from the 50s that uses a selenium light-powered meter, no batteries required, and it still functions just fine.
I miss old school futurism.
Steampunk space stations. :)
There are still proposals by futurists for solar thermal power in space, but scaled up to beam down to Earth or for stations and bases with high power demands. A surface base on something like the moon or even an asteroid could use the heat directly to bake volatiles out of the ground.
Photovoltaics weren't invented until 1954
@@lektwik Yes? And?
As a physics geek once said - "solar cells drink visible light, extract work, and pee infra-red."
When a photon, an electron and a PN junction love each other very much...
@@seanm2511 They aren't old enough for this yet, tell them about the protons and the neutrons.
"Forbidden energy bands" definitely sound like the part of the tech tree I'd put points into.
It's actually criminal how spoiled we are that so much work and research is put into each of these videos.
We can't thank you enough Scott!
Selenium solar cells are semiconductor too. Early rectifiers were made with selenium plate diodes (and gave off a nasty stench if burnt)
Seeing this stuff about how solar cells can be extremely weak LEDs if power is put into them makes me think of how crazy it would be for someone in a fictional setting to secretly send morse via solar cells knowing an enemy is monitoring all normal RF frequencies. but only a still manned friendly science station would be monitoring near visible IR. Since I am guessing what tiny light they do give off is similar in spectrum location to a TV remote. Which digital imaging systems can see.
Solar panels are able to detect a laser pointed at it and this has been demonstrated to be capable of high bandwidth signalling. With a laser to return data, this could be both covert and almost undetectable. Starlink V3 maybe?
Or they could just use a flashlight from a window.
@@RCAvhstape or a laser for extra sneakiness. There was an experiment a while ago where some people successfully signaled the ISS with a pretty low power laser on the ground. And by signal, I mean they could see it out of the cupola window. I want to say Scott has a video on it
I've read a book where (very low bandwidth) covert bidirectional communication is done using LED room lighting.
Arthur C Clarke's _Earthlight_ from 1955 has an astronomer spy on the moon sending messages back (to Mars) by replacing the eyepiece of a vast lunar telescope with a light source, allowing him to send very tightly focused beams of light to waiting spacecraft. This is completely not the thing being described here, but is still pretty cool.
The animation at 3:04 is brilliant! It's exactly what was missing for me in all the other videos explaining how solar panels work.
I grew up in the 1950s and was intrigued by solar energy. They sold little hobby solar cells so you could get your hands on the process. In the 1980s I built a remote weekend house that Progressively became solar powered. I believe the U.S. Gov. Used me and the remote house in a ten years long alien exchange program. My first generator in 1985 had one experimental solar panel sold off by Motorola Government Electrics Group to employees. I ran 12 volt current into the house and I love this arrangement being so simple and fool proof and absolutely dependable. Next went to AC with a small inverter. Then jumped to 3,000 watts with a huge battery pack and three solar panels. I sold the remote house and that generator ran 12 years with no maintenance and was trouble free. Today being retired I live in a van with two inverters two battery packs and one 100 watt China manufactured solar panel. I run two 250 watt Electric heaters for winter heating, lighting, an entertainment center and a small refrigerator.
Your electric setup sounds interesting. Aliens do not care about the American government though, and don't participate in exchange programmes with native fauna 👍
@@johnn1199 Yes alien's run their own show. I was an official involved with military research and at my remote cabin I read the best research findings published at that time. It was under stood that the alien's would gather exchange information from me. I was taken to an ice planet or moon where I must have received extensive modifications. It to appeared that I was taken to earth based alien sites possibly to contribute work on projects. I developed an understanding of ancient Native American mapping and of sites globally related to my cabin site. I also can explain the structure of gravity and the nature of deep space relationships. From secure sources I was informed that I am an descendent of Christ and that I am extraordinary.
its cool when a project I worked on for my degree becomes its own youtube video. I had to write a 5 page essay on solar panel technology and you covered almost all of it in 15 minutes!
Great video, I'm constantly amazed at your scientific storytelling skills. Thanks Scott!
Nice explanation. Simple and tight, but PRACTICAL. I am a RF/wireless engineer and I found that what gave me the best design instincts was UNDERSTANDING THE PHYSICS.
Please Scott, could you make a video explaining and comparing the G forces suffered during launch in differents rockets across the history? Not only for humans, but also equipments. Your videos are simply the bests!! Thanks!
Thanks for this explanation!
I did a physics degree but don't remember any of the bit we had on semiconductors! At least we didn't learn about how solar panels work. I only remember the name 'photo-electric effect' and not the details...! My Dad used to talk about solar cells because he was into electronics and thought he had an idea for making them more efficient, but who knows if any of his ideas were valid or might have been useful! He spent so many years frustrated and unemployed when he could have been doing some useful job somewhere if only there had been something nearby that suited his skills and knowledge. As it is he spent a lot of time reading science and computer magazines and wishing he could contribute a new idea somewhere - so eventuallty he began writing letters to 'important' people telling them how we should 'save the world'!
Hey at least he cared, couldn't say the same about most people today
I just got confirmation today from ESA, that Artemis 1 rollout scheduled for March 17th. Wet dress rehearsal schedule for April 1st-3rd. I'm pumped!
We are still USING AO-7, not just hearing it's beacon. It is still functional in sunlight. Which makes it even more amazing.
> hearing it is beacon
@@Anvilshock Are you a HAM too?
I used OSCAR 7 as soon as it became operational in 1974. I'm in the UK and my first contact via the satellite was on orbit 21.
That was nearly 50 years ago and memories fade but I seem to recall that OSCAR 7 used early COS/MOS (later known as CMOS) logic ICs donated by RCA, the company that invented CMOS technology. The company wanted to find out how well this type of logic survived in the radiation environment of low Earth orbit. As it happens, the ICs survived much longer than RCA, which was bought by GE in 1986 and parts of the company were then sold or liquidated. RCA now exists only as a brand name but the ICs in OSCAR 7 continue to operate.
@@pegasus7607 Thank you for the back story. At a Hamfest before the virus I met the man responsible for the programing of the AO-85, AO-90, and AO-91. He was showing my daughter and I how the antennas were wrapped up with a small bit of fishing line. He told us how his program triggered a resistor to heat up and melt the line to deploy the antenna. It's a great hobby with skilled and passionate people. 73 thanks again
Hi Scott and greetings from Marburg Germany, where my father was involved in building Oscar 7 and other satellites for AMSAT - back in the days. Oscar was conceived and raised in the ZEL, Zentrales Entwicklungslabor fuer Elektronik (Central Electronics Developement Lab) a branch of Marburg's famous University. That place was Skunkworks and JPL at Christmas for me as a teenager - and maybe it actually was in deed.
Thank you soo much Scott for digging this Oscar story up - I wish i could dive into that memory together with my him now.
Best Regards from Marburg, near EDFN, right underneath the MARUN transition of EDDF's SID, fly save!
Perfect timing on this video! Just began making a solar cell today.
I'm glad you corrected the Pu-235 blooper! I worked in the facility at DOE's Savannah River Site where we processed Pu-238 and got to travel to Florida to watch Galileo launch. The cost issue with the material is we just don't have any reactors still operating where you can make much Pu-238 since the reactors at Savannah River shut down. You can make limited amounts in the HFIR at Oak Ridge or at the ATR at Idaho National Labs. But to make reasonable amounts for deep space missions, you'd need to build a new reactor, which isn't cheap, thus the 'high cost' to make Pu-238.
Love this series thanks for doing it again
A follow up video of the whole power management system would be great!
Thanks for another great video!
it always amazes me seeing these spacecrafts with people around them working with them so you can get the scale of the size of them, the size of them makes them all that more impressive...against the seemingly infinite background of space they seem tiny but some of them are huge!
LOL! "If you throw enough of these together into one place, you get a computer" had me laughing, but adding, "you managed to make rocks think" killed me! Good one, Scott! XD
I'm sitting here thinking of my plans for Eve missions. ;) They'll be fine, of course, but I wonder if Realism Overhaul changes solar panels... Eh! I'm not really planning on trying it. :)
AMSAT-1 amazes me! :D
My dad was a ham radio operator who built all his own gear and had stack of QST magazines. =)
finally!! this series is back!!
Lovely Ending. Tonn's of reference points. needed that. Thanks Scott
what impacted me most about this video is how freaking huge sattelites can be
Great series Scott! I heard about Boeing having problems with solar concentrators. The very thin panels had adhesives that got too hot, loosening a little, and the panels warped. Also, the relatively cold reflective film immediately condensed the outgassing material, becoming dark and not reflective. Double whammy.
Yes, it was quite a boondoggle with many of those satellites needing to be replaced ahead of schedule due to unexpectedly fast power degradation. XM Satellite Radio's first two satellites were among the victims.
Thanks Scott for the update and info especially the last bit.
That information about AMSAT is so cool!
I love space science so much.
Always in need of these videos. Thanks Scott!
Awesome video bro
9:30 air bearings in action. . . Nice
Wow: well done. When you started describing the history of solar cells I was mentally lamenting the fact I can't post my photos of Fritz's New York rooftop panels in the comments - and there you are, you've got them. Well researched, sir.
amazing Juno and other probe building footage. Cool to see something on the ground in all it's impressive size, that you only know from 3d animations now.
It takes a bright individual to talk about a very technical topic with this kind of enlightenment.
Super cool to see the SQ limit pop up in one of your vids!
Man reading my mind.. yesterday just had this question on mind .
the Juno panel unfolding clip really blew my mind! i knew it was "kinda big" but didnt knew it was so HUGE!
Been a long time since we've had one of these, glad to see it's back! :)
Great to see amateur radio satellites being given a mention! They are a great way to get into orbital mechanics, space electronics and mechanics. The satellite company SSTL started out life at Surrey Uni, making amateur radio sats.
What a pleasant surprise revisiting Kerbal. My heart aches every time you upload a video and there's no Kerbal involved.
Thank you for this.
Thanks for another excellent video, Scott.
Love it! Thanks Scott. Really well explained. Fascinating.
I am 2 miles from the old Bell Labs building here in NJ (Which is still the inventor of the internet)
Has there been any progress in reducing the cost of multi junction solar panels for something like home PV systems? It would be nice to be able to capture more energy so that heavy usage days still leave enough power to charge your batteries.
probably not if they are still only used on spacecrafts
There may be progress in the future using quantum dots instead of rarer metals for multi junction solar cells.
Traditional multi junction cells use III-V compounds like GaAs, which makes them prohibitively expensive for the consumer market. However, recently there have been commercial developements to build tandem cells out of standard silicon and a new class of solar cells called perovskites, which can be produced cheaply. While this doesn't increase efficiency as much as traditional multi junction cells, it does so much more affordably.
I don't think there's much more point, since efficiency kinda is a strange thing in solar panels. With most other power sources, increasing efficiency means reducing upkeep costs as you need less fuel to do the same thing. Thing with solar panels is, efficiency is just another way of writing the power per square unit of length. So increasing efficiency at high costs just makes less sense than putting more of the things. Commercial solar panels are efficient enough to supply the house they're laid upon without exceeding the size of the roof, and for massive photovoltaic farms the real metric still is watts per dollar spent, not efficiency, because there's no point spending twice as much per solar panel for a marginal gain if you could instead just put down twice as many of the things. In a sense, multi junction solar panels can also be less efficient in a watts per kwh sense, since they take for more effort to make. Really, "efficiency" in solar panels is the conversion factor of incident light to electrical energy, which may not be the actual metric of what we would consider efficient in practise.
The cost per square cm for a GaAs triple junction cell is so much higher than si, that it will never be a real alternative for normal rooftop applications. However there are concentrator pv Moduls availible that need tracking units but can be more cost effective than si. The most advanced cells use up to 5 junctions on top of each other with an efficiency up to 46%. For example by "Azur Space Solar Power".
In the case of the Ham satellite, what mostly likely happened is this.
When a battery fails, its voltage drops close to zero, but its internal resistance remains low.
Time passed, and the electrolyte of the batteries evaporated completely.
Therefore, the internal resistance of the batteries shoot up, to a value that is equivalent to a total disconnection. This allowed the onboard electronics to be powered directly from the solar cells.
Missed this series so much 💪💪
Man i remember watching u play ksp like 7 years ago. Was good times!
Hey Scott, i think we are probable the last 2 people who still have G15 gaming keyboards. Great keyboard btw!
Da! Scott Manley! Tbe manliest Manley of all the man!
I love your content...
Every video you make is gold..
Thanks, Scott
Nice flight sim control yoke…getting some practice in before the real thing, Scott’s new hobby. :)
Take a look at non-imaging photo concentrators. They have an advantage where they can accept a much broader range of incident angles. I've used similar concepts to help make uniform spots from LEDs in making basically the opposite.
Hey Scott
First of all thank you for all the high quality content you have made in the last 5 years. Since you introuduced me into ksp my fascination for Space in generall, has only increased. from Spy Satalites, Cold War experiments , unintuitive Orbital Mechanics to Astroid composition, i gladly suck iit all in.
One Topic which i couldnt find on your channel was the Buran Space Shuttle. I would be highly interested in your disection of this topic, since you are by far the best AstroSciencePublicComunicators out there (if that word even exsits).
And Again Scott, thank you for all the effort you have put in your Videos, truly Legendary Sir!
The angular alignment for concentrating PV isn't as critical as for imaging optics, because they don't need to create a sharply focused image of the sun - they just need to smush the photon flux hitting a given area down into a given smaller area. For example, if you want a concentration factor of 10, you can using reflecting optics get an accepance angle of about 18 degrees.
It's like triple expansion steam engine....but for visible light energy! Amazing video
Excellent video. It recalls my interest in solar energy for home use. I have looked at it continuously over the years but have not yet done anything about it. One thing that always concerned me was the technology. I would read about the newest technology then go to talk with the actual providers and the technology available was always years behind the new technology being reported. All these advances while good down the road would be better if they were available right now or interchangeable so you could take advantage of new developments right away. I am no longer in an area best suited for solar and I'm getting older. I doubt I'll ever use it myself.
The end almost made me emotional. 😉 awesome explainer Scott. Keep em coming I love these deepdives
Interestingly almost all the Solar Panels discussed on famous spacecraft are built by Solar Aero, a company recently acquired by Rocket Lab
Another reason PV works great in space is that PV cells are more efficient as they get colder, below 25C.
So much more so that people who design PV systems have to take into account the extra voltage generated for solar installations in places where you can get very cold, very sunny days!
Actually solar cells get hotter in space because they can’t be cooled easily
The lack of atmosphere does help increase the ammount of photons though. I don't know if the cooling problem ofsets it completely.
@@scottmanley Yeah, "cold" kind of loses its meaning in vacuum... no convection to transfer heat in and out of the system. It's all about radiative cooling... whether you can emit more heat than you're generating and receiving.
It would be totally dope if he did a follow-up video on how to dope for all of use dopes.
Pioneer 5 was the first solar-powered spacecraft to be launched into interplanetary space, two years before Mariner 2 did. Nevertheless, what a great video as always!
It’s only the photons with energy E = fh > band gap that supply electricity... it doesn’t matter how many photons arrived. This was the discovery of Einstein 1905 photoelectric effect.
As an amateur radio operator I loved the Amsat mention. Can you please do a video on some of the other amateur radio satellites sometime?
Dusting off Physics degree, brush, brush, excellent, very enjoyable!
Interesting, you implied that most solar cells in space are silicon, or perhaps multijunction. My understanding was that they were CIGS, because of the higher efficiency and because they were thin film, so could be rolled up without being damaged. I just did some poking around and couldn't find anything that confirms that. Plus your point about using small, rigid but curved silicon pieces on a flexible backer makes a lot of sense.
OMG, I missed this series 😍😍
MY FAVORITE SERIES RETURNS
Very cool episode. Thanks for all your research and knowledge sharing. Would love to see a similar vid on reaction wheels!
when i first saw the RTG in KSP, and it's.. abysmal power output, iwas like "hell nah, never going to use that"
Guess who reconsidered his Gigantor Panel Design when reaching Jool 🙄
REALLY good explanation, Scott.
If anyone really wants to know more on how solar cells work, don't bother. Like Scott said, any more info and you may as well do a Physics degree. As someone on a Physics masters, I agree. The physics involved is complex, but a very interesting kind of complex. The kind that makes you think "who the hell even thought of this stuff". Nice vid Scott! You summed it up well!
I always like the theme music at the end. Hat's off the the composer.
You gonna do a hopefully special ksp2 update? Maybe some special not before seen info..?
Solar power, Nuclear Fusion at a safe distance
Want to know something Cool thing about Solar cells? They're so close to being LEDs and vice versa. If you take a solar cell out of a cheap calculator and hook a power source to the cells power leads in a dark room, it'll glow ever so slightly.
Same thing with LEDs, you take a simple LED, hook a voltmeter to it and expose it to the sun, you'll see a increase in electric flow.
Solar Cells are Light-Absorbing Diodes instead of Light-Emitting Diodes
Diodes are crazy man, probably one of the greatest inventions of our time.
This phenomenon is used in an electronic device called a "photodiode", also in "phototransistors" which are just photodiodes with an amplifying transistor added.
They're available in packages similar to those you find LEDs in, yet they generate a voltage when exposed to light.
IR LEDs and photodiodes are why most remote controls function as well as they do (granted that they modulate the signal on a roughly 40khz carrier wave, but the data is sent nonetheless.
That clip about dividing by zero. Siri answering, "Imagine you have zero cookies and you split them among zero friends." Why she gotta call me out like that?
Yay another one
Great Lab footage of tests on actual spacecraft!
@2:39 "...managed to make rocks think" I had an IT company in 1998 and I named it SmartStone. So glad that somebody sees that silicone in the chips is nothing else but rocks... by the way domain is still for sale. $2mln :)
polycrystalline cells can handle lower light flux than monocrystalline panels. Their maximum efficiency is lower but they are effective in dimmer conditions, one of the reasons you find them on calculators for use indoors.
You should have mentioned mercury boilers which is how they thought space stations would be powered before more efficient solar cells were developed. Reflectors focused sunlight on a tube carrying mercury that would drive a thermal engine to power the station.
"Managed to make Rocks think" Thank You I needed a good belly laugh today.
I even forgot this game existed, I love it.
Wonderful video Scott! One small thing though. You corrected yourself saying Plutonium 238. That's actually the stuff used in reactors and nuclear weapons. Pu-239 is the stuff used in RTG's. Cheers!
Plutonium 239 is the fissile material used in bombs, 238 is used in RTGs
@@scottmanley Urgh! I really shouldn't write comments while have asleep! Sorry about that and thank you for putting me straight again.
Very informative video✨. Also like to know more about how this solar panels helps the spacecraft to sail through space and what r other possible energy sources for spacecraft beyond solar system 🚀
Nice intro to solar cells. Just wait until you try and figure out where to point them! Most people think it’s at the sun but power, thruster plume loading, thruster plume contamination, visiting vehicle plume loading, shadowing, thermals, comm restrictions, drag reduction, risk of failure of motor drive assemblies and latching mechanisms all say otherwise.
Thanks Scott, I love the fantastic graphics in this video!
Multijunction III-V vs silicon is actually not as simple as the efficiency number suggests. Multijunction cells use Germanium substrates that are much heavier than Si substrates. Therefore, the power-to-weight ratio of early multijunction panels are not superior to silicon panels. Multijunction cells are mostly valued for their higher radiation resistance for deep space applications. Using concentrators however changes the math since the cell mass are now a much lower part of total panel weight and multijunction panels have much smaller area and thus lighter structural support.
For future spacecraft, less efficient thin film panels with much higher power-to-weight ratio are desirable. But TF cells have their own set of problems too.
I understand your alma mater is a key centre for research on momentum exchange tethers. I would very appreciate your input on the subject. I am especially interested in the interaction between momentum exchange tethers and propulsion systems that do not use reaction mass (e.g. e-sail) and variable moment of inertia tethers.
I like your videos, is there a video about the technology used by the Maxar satellites that provided the photos during this war on Ukraine: the imaging, orbit, launching vehicles, etc ... ? Thanks
In RTG Plutonium-238 is used, Plutonium-235 would make for a rather short-lived energy source.
The bit at the end about AMSAT-Oscar-2 still running makes me think of the end of the game SOMA.
any specific information on the panels of the webb telescope? thanx for your excellent videos!
I think it's a 2Kw system.