How Does The Sun Power Spacecraft? Things Kerbal Space Program Doesn't Teach You

The most popular power source for spacecraft is Solar panels, dating back to the oldest satellite still in orbit, Vanguard-1. Since then solar panels have seen huge gains in performance and have allowed spacecraft to go deeper into the solar system than ever before without resorting to expensive nuclear power sources.
Solar cells are semiconductor devices which exploit quantum mechanics to drive electrons around a circuit and generate power. They actually date back over a century, but modern technology makes them 30 times more powerful than the first panels ever used.
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[@QuantumHistorian]

_"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.

[@impguardwarhamer]

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

[@QuantumHistorian]

@@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"_

[@Michaelonyoutub]

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.

[@azpcox]

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.

[@bobshowrocks]

@@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.

[@MonkeyJedi99]

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.

[@Robbedem]

It's one of those rare mutations that has a benefit. ;)

[@krissp8712]

I beg to differ, it sounds like something out of an Asimov story!

[@DUKE_of_RAMBLE]

""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........ 🤔**

[@tobiwonkanogy2975]

mission failed successfully .

[@YorBraakman]

If someone wrote that you would then call it lazy writing!

[@renew1572]

The all loved format has returned!!!

[@jojo_da_poe]

How this comment has nearly 300 likes and no comments is beyond me.

[@renew1572]

@@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

[@TeeBar420]

There is something beautiful about amsat's battery failing so completely that it started working again.

[@timboatfield]

Totally! A deeper dive into what and how is suspected to happen would be fun and interesting. *@ Mr Manley ?*

[@lmamakos]

@@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.

[@timboatfield]

@@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.

[@Thermalions]

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.

[@leogama3422]

The mission failed successfully.

[@ItsHaldun]

"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...

[@MrCrackbear]

trees are made of sugar

[@2ebarman]

Moon is motly made out of silocon dioxide, lets make it think :D

[@Anvilshock]

It's not really thinking, though. It's just cleverly switching currents as designed. Moderately impressive, but hardly mind-blowing.

[@GewelReal]

Humans are just carbon and water

[@GewelReal]

Humans are just carbon and water

[@xenowreborn]

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

[@-danR]

I had no idea that solar panels... on top of _roofs_ ... were a 19th century innovation.

[@linyenchin6773]

@@-danR Tesla wasn't the only electrical Engineer of that era, looks like a lot of bright lights bloomed alongside him.

[@azgarogly]

@@linyenchin6773 lol

[@HalSchirmer]

As a physics geek once said - "solar cells drink visible light, extract work, and pee infra-red."

[@seanm2511]

When a photon, an electron and a PN junction love each other very much...

[@jojo_da_poe]

@@seanm2511 They aren't old enough for this yet, tell them about the protons and the neutrons.

[@matthewbeasley7765]

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.

[@finnsk3]

Beat me to it.

[@ke6gwf]

I was thinking the same thing! Lol

[@owensmith7530]

I spotted that too, and I know very little about this except I paused the video and read the AMSAT posting shown.

[@daanwilmer]

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

[@Nainara32]

"Forbidden energy bands" definitely sound like the part of the tech tree I'd put points into.

[@RCAvhstape]

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.

[@BravoCheesecake]

I miss old school futurism.

[@TheOneWhoMightBe]

Steampunk space stations. :)

[@Br3ttM]

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.

[@lektwik]

Photovoltaics weren't invented until 1954

[@RCAvhstape]

@@lektwik Yes? And?

[@camolog]

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!

[@sashimanu]

Selenium solar cells are semiconductor too. Early rectifiers were made with selenium plate diodes (and gave off a nasty stench if burnt)

[@filanfyretracker]

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.

[@timboatfield]

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 they could just use a flashlight from a window.

[@moonasha]

@@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

[@AlexandervanGessel]

I've read a book where (very low bandwidth) covert bidirectional communication is done using LED room lighting.

[@hjalfi]

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.

[@35571113]

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.

[@alexbillingham9593]

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!

[@josephpiskac2781]

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.

[@johnn1199]

Your electric setup sounds interesting. Aliens do not care about the American government though, and don't participate in exchange programmes with native fauna 👍

[@josephpiskac2781]

@@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.

[@myronalcock4716]

Great video, I'm constantly amazed at your scientific storytelling skills. Thanks Scott!

[@richb313]

Thanks Scott for the update and info especially the last bit.

[@fdavidmiller2]

Always in need of these videos. Thanks Scott!

[@TobiasDettinger]

A follow up video of the whole power management system would be great! Thanks for another great video!

[@BodeBoi-dt3hg]

Love this series thanks for doing it again

[@diraziz396]

Lovely Ending. Tonn's of reference points. needed that. Thanks Scott

[@baomao7243]

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.

[@MrTomcatt310]

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!

[@TonyGouge]

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.

[@Galactis1]

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!

[@mastershooter64]

finally!! this series is back!!

[@joyl7842]

That information about AMSAT is so cool! I love space science so much.

[@haxi52]

Very cool episode. Thanks for all your research and knowledge sharing. Would love to see a similar vid on reaction wheels!

[@GalileoAV]

Been a long time since we've had one of these, glad to see it's back! :)

[@addisonp.6373]

Perfect timing on this video! Just began making a solar cell today.

[@non-human3072]

Awesome video bro 9:30 air bearings in action. . . Nice

[@5Andysalive]

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.

[@realfoggy]

We are still USING AO-7, not just hearing it's beacon. It is still functional in sunlight. Which makes it even more amazing.

[@Anvilshock]

> hearing it is beacon

[@realfoggy]

@@Anvilshock Are you a HAM too?

[@pegasus7607]

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.

[@realfoggy]

@@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

[@johnannan2506]

Love it! Thanks Scott. Really well explained. Fascinating.

[@alexstergaard3551]

Missed this series so much 💪💪

[@yahccs1]

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'!

[@BravoCheesecake]

Hey at least he cared, couldn't say the same about most people today

[@Flightcoach]

The end almost made me emotional. 😉 awesome explainer Scott. Keep em coming I love these deepdives

[@leonlerdo]

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!

[@Enderhuhn]

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!

[@jameslemon5073]

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.

[@RobertHancock1]

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.

[@F1fan4eva]

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.

[@ponyote]

Thanks for another excellent video, Scott.

[@iitzfizz]

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!

[@eekee6034]

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

[@Madsstuff]

I love your content... Every video you make is gold.. Thanks, Scott

[@erichaynes7502]

Thanks Scott, I love the fantastic graphics in this video!

[@Allan_aka_RocKITEman]

Great vid, Scott...👍👍

[@babysnaykes]

Super cool to see the SQ limit pop up in one of your vids!

[@stefanomorandi7150]

the Juno panel unfolding clip really blew my mind! i knew it was "kinda big" but didnt knew it was so HUGE!

[@ropshubop]

MY FAVORITE SERIES RETURNS

[@rogerstone3068]

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.

[@Adelhight]

Great Lab footage of tests on actual spacecraft!

[@ronjon7942]

Nice flight sim control yoke…getting some practice in before the real thing, Scott’s new hobby. :)

[@rocroc]

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.

[@Zadster]

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.

[@neiljopling4693]

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.

[@tejasbirute4838]

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 🚀

[@k7iq]

REALLY good explanation, Scott.

[@steveshoemaker6347]

Very good...Thanks Scott...👍👀

[@zeg2651]

OMG, I missed this series 😍😍

[@Thrawnio]

Man i remember watching u play ksp like 7 years ago. Was good times!

[@RustyorBroken]

It takes a bright individual to talk about a very technical topic with this kind of enlightenment.

[@TianarTruegard]

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?

[@dgsindelar]

thanks for another fascinating video Scott Manley. I've got some advice for your flying lessons.... Fly Safe :)

[@opj4you]

Another great video!

[@happysalesguy]

Thanks, Scott! I learned a lot!

[@rishiparitala88]

amazing series

[@crackedemerald4930]

what impacted me most about this video is how freaking huge sattelites can be

[@luigiking89]

Man reading my mind.. yesterday just had this question on mind .

[@derrekvanee4567]

Da! Scott Manley! Tbe manliest Manley of all the man!

[@stormycatmink]

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.

[@MrShakespeere]

Hope you're feeling well Scott!!

[@InfoPoint_the_best_gamer]

What a beautiful note to close on.

[@misterphmpg8106]

any specific information on the panels of the webb telescope? thanx for your excellent videos!

[@TheEvilmooseofdoom]

I think it's a 2Kw system.

[@Najolve]

It would be totally dope if he did a follow-up video on how to dope for all of use dopes.

[@DeltaV2TLI]

It's like triple expansion steam engine....but for visible light energy! Amazing video

[@sandycarter3731]

Hardly understood a word but I could listen to you all day!

[@a176]

hi scott it would interesting to hear an explanation on satellite electronics ... specifically how do satellites deal with grounding/static build up, since obviously they can't ground to the earth?

[@darrengladstone3159]

Scott your channel is so good, I would subscribe twice if I could.

[@Ava31415]

Dusting off Physics degree, brush, brush, excellent, very enjoyable!

[@oldschoolman1444]

My dad was a ham radio operator who built all his own gear and had stack of QST magazines. =)

[@-pickle-4726]

You gonna do a hopefully special ksp2 update? Maybe some special not before seen info..?

[@RobinHagg]

Cool finish

[@MarkReedman]

Hi Scott I thought stirling heat engines were also used in space such as the resonant variant with its higher efficiency.

[@travcollier]

The bit at the end about AMSAT-Oscar-2 still running makes me think of the end of the game SOMA.

[@alexwalker9803]

In this video you explained it better than the power systems engineer did in an hour earlier today. Really need to do a collaboration with you on our mission for ESA

[@dig1035]

Fascinating!

[@w-dad4040]

great stuff

[@samryan3299]

That was a cool fun fact at the end

[@acevtura4244]

Hey Scott, i think we are probable the last 2 people who still have G15 gaming keyboards. Great keyboard btw!

[@Andrew_Fernie]

Good one that, Scott 👍

[@blue_3675]

I even forgot this game existed, I love it.

[@Bramon83]

Dude the outro music was so crisp. You change anything up there space DJ?

[@sfsfilms2626]

Yay another one

[@Relkond]

I foresee future high-spec solar panels using prisms or diffraction gratings to minimize losses around the band-gap.

[@jakethesnake630]

You da man Scott!!!

[@zuthalsoraniz6764]

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.

[@blitzkreg335]

This was really cool.

[@TheDesktopOrbinaut]

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!