USA Put A Nuclear Reactor In Space And Abandoned It - How Did It Work?

In the early days of the US Space program there was a parallel nuclear power program to develop the nuclear power technologies needed for spaceflight. The Space Nuclear Auxiliary Power (SNAP) program worked on both isotope decay generators and fully operational fission reactors. And while several spacecraft have been launched to other planets using radio isotope generators, the US only launched one fully operational test reactor - SNAP 10A which operated according to predictions from ground tests. Until the host spacecraft failed 40 days into the mission.
While the concept was proven, no mission could be matched to the capabilities and no other test reactors have been flown by the USA.
(The Soviet Union on the other hand flew several)
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[@TheStormpilgrim]

"So, what do you want to launch on this mission?" "A nuclear reactor with 93% enriched uranium." "Huh. That's pretty rich. How do you plan to cool that?" "Highly reactive alkali metals." "Hmm. Interesting choice. And your going to get it up there how?" "With a crap-ton of highly corrosive, hypergolic rocket fuel, of course!" "Solid choice. Hey...is that your car?" "Yeah! Just bought it. It's a Corvair!" "ARE YOU MAD?! THAT THING'S A DEATHTRAP!!!"

[@anncodec]

Let the open bidding begin.

[@mgancarzjr]

"Hi, I'm from Rocketdyne. Can I interest you in our tripropellant rocket engine? It burns a mixture of liquid lithium, gaseous hydrogen, and liquid fluorine. The exhaust corrodes glass - an added bonus."

[@marklarma4781]

@@mgancarzjryou forgot the most important part. It’s incredibly efficient.

[@johnfeistner467]

Bad part is the town i grew up in had a curve called Corvair Curve on the way out of town due to how many Corvairs wrecked there

[@yyyy-uv3po]

I swear sometimes 1960s tech still looks futuristic.

[@kylebeatty7643]

In my case, I would call it the Johnny quest effect. One exception here is the aluminum baking pan being used to cook fuel rods.

[@LuciFeric137]

The modern era was mostly invented by 1946. Mankind peaked in 1969. Everything since is derivative.

[@miguelmouta5372]

@@LuciFeric137Better say it started a bit earlier with Sir Isaac Newton.

[@markedis5902]

@LuciFeric137 I’m assuming you’re Gen Z and are just unaware of all the developments in the 70s, 80s and 90s.

[@LordFalconsword]

Because we abandoned all our dreams for 50 years.

[@blurr220]

TIL that there is a nuclear reactor that isn't powerful enough to power my pc. I don't know what which one it says more about, but it says something.

[@volvo09]

500W from 30kw is pretty darn bad!

[@eeengineer8851]

@@volvo09 Yes. I wonder how much better it could be with more modern stuff? Thermocouples don't generate a lot of voltage for the heat differential either.

[@skunkjobb]

A normal PC draws far less than 500 W. Do you have some extra powerful gaming computer?

[@db1481]

@@eeengineer8851 I'd imagine it's an experimental design thing. Spacecraft engineers are allergic to moving parts as their reliability is inherently poorer than fixed structures. The experiment in this case was to demonstrate reliable reactor control in the space environment so I'd imagine they were averse to the risk of not completing that demonstration by including a heat engine of any sort and particularly not a fast-spinning Rankine cycle turbine like Scott discusses. Such a heat engine would've been responsible for cooling the reactor in addition to generating electricity so it's not something you can just tack on as an afterthought. That said, current developments such as NASA's Kilopower experiment focus on integrated solutions for heat generation, electricity conversion, and cooling. The Stirling generator used with the KRUSTY reactor is vastly more efficient than the thermoelectric generator used on SNAP (and also in the radiothermal generators commonly in use). The demonstrated reliability is getting there and it's possible we'll see radiothermal Stirling generators on the next generation of space probes in advance of a reactor application.

[@skunkjobb]

@@eeengineer8851 0,5/30 kW is 1,7 % el. efficiency. The RTG on the Perseverance rover (launched in 2020) is at 5,5 % but that's not better than the old Voyager probes from the 70s so not much has happened in that field in 40 years.

[@sirjohniv]

Excuse me, sir! Can you direct me to the naval base in Alameda? It's where they keep the nuclear wessels

[@vincei4252]

Nuclear Weasels.

[@kotori87gaming89]

I think it's in Alameda!

[@lordneeko]

Classic!

[@wolfecanada6726]

"Everybody remember where we parked!"

[@pseudotasuki]

Double dumbass on you!

[@doncogswell9596]

My father worked for Atomics International and worked on the SNAP 10A as a design engineer. He said it was an engineering marvel.

[@daszieher]

It still looks like one when seen from 2024!

[@crbielert]

I'd be inclined to agree. In that assembly footage, you can even see how the reflector modules hinge so they could be flipped away from the core in the event you need to perform emergency shutdown. Amazing to miniaturize something like a reactor that much, back then and today.

[@scottmedwid1818]

My father worked it, NASA Lewis in Cleveland and the Plumbrook nuclear test center in Sandusky Ohio. He was working on the SNAP-8DR heat exchanger and turbo alternator power system. we went out to California a couple of times in the late 60s when he was testing at Atomic International.

[@willamcombs1106]

My Dad worked at Aerojet General in Azusa, Ca. in the late 50's through the 60's. He worked on the Snap 8 project and I remember him talking about it using liquid NAK and highly pure hydrogen peroxide. I remember him talking about the danger using some of the chemicals used in the construction. I know He also worked on NERVA and the Mark 14 torpedo while at Aerojet General. Seeing your video brought back some fond memories of my late Father. Thank You.

[@BackYardScience2000]

I wonder how the NaK and H2O2 worked in the Snap 8? The NaK is extremely reactive and will explode if any moisture contacts it, especially if H2O2 contacts it. They'd have to be in totally different systems within the item and far away from one another to keep any potential accidents from completely destroying everything. I have videos on my channel showing what NaK does in water if you're curious.

[@davyaldy76]

Scott I recently flew from Perth to Sydney, stayed a week and came back yesterday. On a couple of occasions I saw a group of pilots, all men, talking and as I walked past them I said, "Fly safe gentlemen." That is your influence on me.

[@Neverwinterx]

7:35 Plasma wind tunnels? That brought me to interesting web pages.

[@redshot9616]

uhhh what pages?

[@anteshell]

You're not supposed to Gawkle every new word you see on Internet.

[@patreekotime4578]

We need an episode on this topic.

[@redshot9616]

@@anteshell uhhh what Is he talking about

[@jonathanchester5916]

Is that like a giant dragon coughing ?

[@kylebeatty7643]

"plasma wind tunnel" just casually thrown out there

[@nigeldepledge3790]

No home should be without one . . .

[@kylebeatty7643]

"A household disintegrator beam!" -Fobidden Planet

[@LordDustinDeWynd]

6:36 Yep, and lighthouses used mercury to provide frictionless "bearings" for the lenses, back when.

[@ekij133]

Some of those older lighthouses still do. It's 'safer' to leave the mercury where it is, in the lighthouse than to try and remove it. A bit like if you have mercury fillings, you're going to ingest more mercury in the process of replacing the filling than you are just leaving it alone.

[@Josh_728]

@@ekij133 M-m-mercury fillings? 😶

[@LordDustinDeWynd]

@@Josh_728 old school

[@ekij133]

@@Josh_728 Mercury Silver amalgam fillings. Very common 20+ years ago. A good balance of hard, stable and not brittle. They also used to put lead in gasoline to improve combustion and lead in paint to stop if fading.

[@alexandermathar7780]

This is the true Basis of all the creepy stories of lighthouse keepers going crazy. Oh that delicious methyl mercury !

[@rnedisc]

When you say "the (1960s) scientists weren't even done yet" I was honestly expeting you to tell us they were planning on using liquid fluoride as a coolent or some shit like that, lol.

[@BillyNoMates1974]

not dilithium crystals like in Startrek ?

[@KatanamasterV]

Alexander the ok fan?

[@dannypipewrench533]

If only they did. I am sure breeder reactors will follow, but it would be nice just to get any nuclear reactor up right now.

[@absalomdraconis]

Please no fluorine coolant, that sounds at least as dangerous as the nuclear fuel.

[@daszieher]

​@@absalomdraconisnuclear fuel isn't dangerous. It only has a few properties that in proximity are harmful to organisms. In my view, the word "dangerous" is over-used and usually intended to incite fear.

[@unvergebeneid]

1:54 I can relate. What I find critical about myself is also less the mass and more the geometry!

[@Kelnx]

Great job on the explanations here. As a nuclear guy, I'm always surprised at how many science content creators get just basic reactor stuff wrong. Yes, absolutely, nuclear geometry is VERY important in reactor design. Not only to achieve criticality, but also for safety and control. I find it interesting that they had hafnium in the fuel cladding. Hafnium is a big (BIG) neutron absorber and is often used in control rods to reduce neutron flux and "slow a reactor's roll" so to speak. Or shut it down by inserting all or a certain group of control rods into a core (aka SCRAM). Normally hafnium and zirconium are found together in nature, and to use zirconium in fuel cladding (Zircalloy, the most common type) the hafnium has to be processed out so it doesn't inhibit fission. Maybe they allowed some small amount of hafnium to act as a neutron poison? I'm not sure. It seems like with such a small mass of U-235, they wouldn't really want a poison. Then again, maybe just removing the reflectors wouldn't be enough to quickly shutdown this little core without a preexisting poison in the fuel cladding. I'd like to know more about this. All I remember from all of the materials stuff I had to study in school is that hafnium = bad in fuel cladding.

[@KevinBalch-dt8ot]

Light Water Reactors use high neutron cross section materials such as boron or gadolinium as burnable poisons fabricated as discrete rods or mixed with the fuel to compensate for the high reactivity of a brand new core. Being highly absorbent of neutrons, they deplete somewhat quickly as fission products build up to add negative reactivity. The designer might have selected hafnium because the core was quite compact, high initial enrichment as well as materials concerns such as melting point and compatibility with the NaK coolant. My “Chart of the Nuclides” (no REAL Nuclear Nerd should ever be without it) is boxed in the garage. Maybe I’ll dig it out and see if which isotopes of hafnium they might have used.

[@gizmophoto3577]

A poison could also be used for power shaping, though it might be easier to vary enrichment of the fuel elements in a design like this.

[@marshja56]

Actually there was NO hafnium in the cladding. Scott got the composition of Hastelloy-N wrong. He said he believed it was hafnium and tungsten but actually it is a nickel based superalloy that does not have any hafnium at all. As you noted hafnium is a neutron poison and using it in the clad would have meant this reactor would be have been able to go critical.

[@i-love-space390]

I love all of those cool retro space animations. They were much cooler than the latest computer animation we have today.

[@KevinBalch-dt8ot]

And many of the projects actually got built!

[@RCAvhstape]

All of those old government training films had good artwork and explained things very well, stuff like how an engine works, etc.

[@liam3284]

That's because artists were paid and given time to make that stuff. Today is far more rushed.

[@syn3rax]

I gotta say the AI upscaling on this archival footage looks *real* bad.

[@r3dn0w]

Yeah, it doesn't look very "I" - if it is supposed to be AI.

[@randbarrett8706]

I dont notice anything, is the video footage from 60 years ago supposed to look better?

[@tico5602]

@@randbarrett8706if you look at the details, they all get distorted in someway, structures are wobbling.

[@mjfan653]

Well, film originally is cinema quality. But, for TV and now digital media that film was scanned. And often with archival footage, it was scanned in 1995 with 1984 tech. And then compressed when wandering the internet. That's why we often get 360p quality videos from things that were originally crisp enough for HD or more.

[@syn3rax]

@@mjfan653 okay sure, but then it was upscaled using AI and it looks *worse*. You look at that satellite dish at 11:32 and tell me that looks better than a 360p video

[@senorelroboto2]

Hastelloy is one of the nickel based superalloys like inconel

[@christophermarin9125]

Thank you, you beat me to it!

[@billpotmesil]

Did Scott call it Hastium? I have heard of Unobtainium, but never Hastium.

[@jannikheidemann3805]

I have heard of it in the GregTech Minecraft mod. It apparently takes a long time to make.

[@rkstealth7699]

AI upscaling can be spooky sometimes

[@joepeck2942]

AI tends to create things as if it were on LSD

[@csdn4483]

A lot of people don't realize how pervasive the SNAPs were. Most people don't realize this, but when Neil Armstrong left the Lunar Module for the first time, he was actually going out to grab the plutonium rod for their SNAP and move it from one leg of the lander over into the SNAP to begin powering the Lunar Module.

[@TheEvilmooseofdoom]

You are in error. The LEM was not powered by the SNAP, it was the ALSEP package that was started on Apollo 12.

[@csdn4483]

@@TheEvilmooseofdoom which created its electricity by way of a SNAP/RTG. Dig a little deeper, you'll see that it was a SNAP effectively providing the power.

[@zolikoff]

@@csdn4483 Yes, that one and most of the SNAPs were RTGs, not reactors like the one in the video.

[@csdn4483]

@@zolikoff SNAP stands for Space Nuclear Auxiliary Power. There were a large number of SNAP designs, a fair number of them RTGs. However, they're all revered to as being a SNAP. Having received my degree in Nuclear Engineering, several of my professors talked about various ways of producing power from nuclear means. One of my professors actually worked on Kiwi/NERVA. This also lend to the various SNAP designs, but the thing to realize is this: NASA called anything, even an RTG, a SNAP.

[@nzoomed]

@@TheEvilmooseofdoom Correct, it was an RTG, not an actual reactor.

[@douginorlando6260]

For any space applications past Mars or in cold temperatures on Mars and the Moon, heat from the reactor is as valuable as the electricity.

[@npexception]

please don't use those weird AI upscalers. The footage looks super weird, especially with people in it. I think original footage should be preferred even if the quality isn't that great. I wouldn't be surprised if the fake details that are sometimes inserted by upscalers would trigger some conspiracy theorists...

[@invasivecoyote1361]

Nooooo. The ai look good!!!!!!

[@sadierobotics]

I agree wholeheartedly. Show us what it really looked like, warts and all.

[@chadportenga7858]

13:00 Love the hand drawn "animations" they used to use.

[@MrHeuvaladao]

Humans are despising a safe and reliable source of energy. Nuclear.

[@nightshift5201]

There's nothing like 1960s animation that brings back sweet memories of my childhood.

[@jeremyglass4283]

one more important thing about NaK, if it comes in contact with water, its EXTREMELY explosive, so please know what you are doing with it!

[@liam3284]

It donates electrons, rather violently, given half a chance.

[@tachyonmkg55414]

good video as always but the AI upscaling on the old footage looks absolutely awful

[@michaelwilliams2593]

6:28 Love the architecture of the Vandenberg entry gate

[@BusstterNutt]

Thank you for all the hard work in making these excellent videos.

[@briananderson4032]

Excellent as usual. Really liked this one in particular. Thank you.

[@kristensorensen2219]

This tiny reactor is quite something! Thanks for sharing this with us!💛

[@johncashwell1024]

You do know, there is a fusion reactor in space already. It's been there for years...

[@CptJistuce]

It is awkwardly located for a large swath of missions, though.

[@KevinT3141]

​@@CptJistuceAlthough hundreds of missions are already using it successfully.

[@LuciFeric137]

Shhhhh. Practical fusion is just a few years away...

[@MeteorMark]

Only one? 🤔

[@CptJistuce]

@@KevinT3141 I did not say it was useless, just that it is not suitable for a lot of missions. It doesn't work on the dark side of the moon, or out past the asteroid belt most of the time(Juno manages to use it, but there's some comically large power capture equipment needed to make the reactor usable)

[@apostolakisl]

Love your history of space/rocketry videos. Well done!

[@samedwards6683]

Thanks so much for creating and sharing this informative video. Great job. Keep it up.

[@Mrcometo]

1:30 Ah, the good old times, when you worked with beryllium with no face mask and putting the fuel rods using simple gloves...

[@Muonium1]

The fuel rod assembly is done with simple gloves today. Natural and even highly enriched uranium isn't radioactive enough before its undergone fission and criticality to bother with shielding.

[@jeromethiel4323]

​@@Muonium1 Uranium is an alpha emitter, perfectly safe to handle with gloves, as you stated. Now, the toxicity of the metals themselves, different story. Plutonium, for example, is toxic as hell, so the danger isn't the radiation, it's the simple fact it's poisonous.

[@Muonium1]

@jeromethiel4323 most of the danger from plutonium is the radiotoxicity though. Ingested high activity alpha emitters are HIGHLY dangerous.

[@TankR]

Smoking was good for you too, back then. It wasnt until colors came along that everything started becoming dangerous.....Things were much simpler when the world was black and white.....Why does everyone look mad? What did I say? Im just trying to say that when colors were introduced everything became crappier all around!!! STOP YELLING AT ME, IM RIGHT!!!! hrm? Hold on I cant hear my friend, Tyrone. What Tyrone? ...... Thats not what I was sayin at all! Did you think...umhm...Exactly, no rational person....what...........Yeah, no kidding. The scary part is these people are allowed to have drivers licenses too.....Fuck it, lets leave these kneejerk bigots to their little mind games. Wanna invite Sally over for dinner, Carol hasnt seen your wife in a while I think shed love catching up.......[walks away with Tyrone ....whos white. Because white people can be named Tyrone too. Our token black guy is named Steve, hes the guy in the back laughing his ass off....and our designated driver. If we're gonna drink, he doesnt want us to drive.... Good guy, that Steve.]

[@JPMadden]

This was back when the U.S. was still conducting nuclear tests as part of "Project Plowshare," one of the worst ideas in modern human history. The idea was to use nuclear explosions to excavate civilian construction projects. One proposed use was to expand an underground aquifer so that the then-irradiated water could be accessed for irrigating crops for human consumption. Others included using many bombs to dig second canals in Panama and Suez. Genius! Thankfully, they never did anything besides testing. I'm always mystified why it took humanity at least 20 years after 1945 to comprehend that nuclear fallout was unhealthy.

[@tomsteuverkb8dxn132]

I worked at the facility that probably refined the uranium and made the fuel rods. It was a DOE site near Cincinnati called FMPC (Feed Materials Production Center).

[@danieldare2640]

I think that was one of the best videos you have ever done thanks so much super informative and full of detail thank you again.

[@nickprince7971]

I love these stories, Scott. Please never stop.

[@nokbeen3654]

This isnt AI upscale, this is evidently AI downscale. My god, At First I thought I had done acid.

[@TheBackyardChemist]

Period correct for the 1960's

[@randomnickify]

AIcid 😅

[@jamesogden7756]

​@@randomnickifyThat sounds scary AF. 😂😂

[@root42]

Yeah, great video, terrible upscaling. Just give us the original footage! :)

[@pavuk357]

​@@TheBackyardChemistno it isn't. It is just old and very crappy film digitalisation. There is likely original film somewhere in the archives, just nobody bothers to scan it. It is 80s that look bad because most of the stuff was captured on magnetic tape at 480i top and degraded through the years.

[@dossantos9389]

Thank you for ripping this story out of the darkness of history 😊

[@TankR]

Its not a secret. There is an entire group of wiki pages outlining the entire SNAP program. Not having heard of something before does not mean its a deep dark secret. And may of the 'facts' implied in this video are quite wrong. I highly encourage you read the SNAP 10 wiki for yourself. Its quite interesting, and a great example of a reactor designed to fail safely and it did. Then got hit by russian space junk....😒

[@Allan_aka_RocKITEman]

Great video, Scott...👍

[@gcm4312]

exceptional video. this was super interesting!

[@kelseyduerksen6404]

Thanks Scott, for pronouncing "niche" correctly.

[@bwjclego]

"Launched into a high stable orbit for safety" vs "Soviets used reactors in low orbit for drag reasons" is a hilarious juxtaposition.

[@liam3284]

The USSR had a terrible environmental record.

[@Niightblade]

I like how stable this old launch footage is compared to the shaky-wobble-fest we have have these days.

[@MCsCreations]

Fascinating history indeed! Thanks, Scott! 😊 Stay safe there with your family! 🖖😊

[@renanmonteirobarbosa8129]

The research was not abandoned, just slowed waiting for a brighter future to emerge

[@mvg2993]

What is going on with the faces and fingers in the clips after 2:00? Is there AI coloring going on here? It looks very odd.

[@thetoasterisonfire2080]

It is an ai filter that is upscaleing and increasing the framerate of the original video. Although doing a poor job.

[@mvg2993]

@@thetoasterisonfire2080 oh that's a shame. I'd 100x rather look at low-frame rate low resolution originals than whatever this AI is making :(

[@lordneeko]

​@@mvg2993no you wouldn't... You wouldn't be able to see any of the details on your high resolution device

[@georgeau2523]

I wasn't sure if I was under the effect of drugs or if it was some AI editing

[@thetoasterisonfire2080]

@mvg2993 If you get the settings right and let it cook long enough it can produce good results. But this is especially crusty.

[@BuzzSargent]

Great report.

[@brettwoodard167]

That was pretty interesting, thanks Scott.

[@elkippy]

some of the attempts at ai upscaling in this video look absolutely terrifying idk what's going on with that

[@TheEvilmooseofdoom]

Terrifying?

[@Muonium1]

At a power level of only 30 kW and an operating time in space of barely a month, the burnup fraction of such a reactor was very, VERY low, barely half a percent of the burnup of normal reactor fuel in a PWR; and so while definitely still dangerously radioactive, the core of this reactor would have been *nowhere near* as intensely, fatally radioactive as normal spent fuel rods glowing in their cooling pool at the average nuclear power plant. Well over half a century now since it was operational, the radiation level will be far lower still than when it was shut down and while I wouldn't want it landing on my house or burning up in the sky over my city, the radiation doses to people on the ground if it did so today would be almost immeasurably minuscule.

[@elmofeneken4364]

Great video Scott. I don't know of anybody else who would enlighten us with topics of space interest like this that don't quite have the entertainment value some space fans look to see.

[@michaelsershen5702]

Hastelloy is a nickel based superalloy. It was one of the first superalloys developed, primarily for use in jet turbine blades.

[@briansilver9652]

Thermocouples or Thermopiles? From my memory Thermocouples are used for millivolt temp measurement while Thermopiles can be used to generate a usable power for low power devices. I guess with enough in series/parallel you could power anything?

[@scottmanley]

Thermopiles are made up of lots of thermocouples

[@quantumblur_3145]

It's a pile of couples, otherwise known as a rhermopolycule

[@DrVort]

It is also kind of terribly inefficient

[@volvo09]

​@@DrVort I wonder if they are similar to the "power pile generators" in gas furnaces used to keep the gas valve open. They make a few milliamps.

[@DrVort]

@@volvo09 I have no idea about a particular appliance you are talking about, but yeah, they are weak, inefficient, convert to electric potential any thermal potential directly ^^ It's just two metals with particular chemistry that make this effect. I guess many of modern portable coolers use similar process, but in reverse.

[@andrewfidel2220]

I think the risk of unintentional contamination from leaking mercury coolant would easily be offset by higher efficiency in coal fired power plants since coal contains lead, mercury, uranium, etc. which were all released as part of the normal operation of the plants. My favorite rebuttal for anti-nuclear crazies is that they did nothing about coal plants, each or which put more radioactive contamination into the environment each year than all Western accidents did total over more than half a century of operations.

[@05Matz]

Yeah, coal is just... so awful it's hard to express how much better basically anything else is. Even other fossil fuels, and those are still terrible! Bits of random heavy metals (including the radioactive ones) scattered everywhere over a wide area, acid rain, not to mention the global warming. But it's so cheap you're not allowed to criticize it unless you have a replacement that's _perfect in every way_ ...

[@bewilderbeestie]

IIRC, coal plants world-wide put about one Chernobyl-worth of nuclear material into the atmosphere each year.

[@kimchristensen2175]

I'm sure the "eco-nuts" don't like coal plants either! 🤦‍♂

[@davesextraneousinformation9807]

Hey Scott, thanks for this history episode. I really enjoy them. This gives me a chance to relate a story my Dad told me. He worked for the company that built the first ion engine that was flown into space. I don't remember that it went up with the Snap reactor. The company was Electro Optical Systems, EOS, in Pasadena California. The ion engine was built under a contract from MIT, or some university like that. Like you said, when the engine was in space and turned on for testing, the high voltage power supply arced and shorted out. The power supply was in some kind of sealed container that kept some of the air inside. Ground testing showed no problems because air is a good insulator at atmospheric pressure. In flight, the container leaked sir down to a pressure where the air ionized when the power supply was turned on Lesson learned; next engine had ports to bleed out the air. Twenty or so years ago I went online to search for any information on the engine. I think the Smithsonian had a copy of it. Plus, they had an experimental ion engine made by Dr. Robert Goddard. It seems that the concept for an ion engine has been around for a long time!

[@josephpiskac2781]

That is really great stuff THANKS.

[@MatthewHill]

Boiling mercury with a nuclear reactor. In space. Lovely.

[@evanfinch4987]

whats the problem

[@benoithudson7235]

Intended to burn up on re-entry. Just to make sure.

[@okman9684]

OH SNAP!

[@emlinder]

Very interesting as usual! Have you considered doing some videos looking at the development and use of RTGs in spaceflight?

[@stevenswapp4768]

Thank you, Scottward

[@tbjtbj7930]

Scott Manley: Notice how big the radiators have to be in space. Stanley Kubrick: Nope.

[@KevinBalch-dt8ot]

Just before the first view of the space station in 2001, there is a view of a satellite with large panels that appear to be radiators.

[@user-ob7cx6bb7r]

Yes, major shift from book to movie in regards to this.On another note, how about the spartan PPE for the technicians.

[@GregBadabinski]

The 1960's (and, to a lesser degree, the pre-sixties) really was the craziest decade. I'm assuming that in the clip you first showed when talking about NaK, the guy is just casually shaking chunks of Sodium or Potassium metal out of that HUGE can. No gloves, no forced ventilation or fume hood, and who knows if he was wearing eyepro.

[@ligmasack9038]

Who needs "Eye-Pro" when you have Saftey Squints?

[@BillyNoMates1974]

I think it's safe to say that guy is no longer walking around any more

[@JarrodFrates]

What about the guy reaching into the spinning machinery with zero protection?

[@GregBadabinski]

@@JarrodFrates that's also very bad! I own a manual Sheldon metal lathe from the late 50s (previously owned by the USAF, funnily enough), so I think my brain's pattern recognition system saw that and said, "oh, we've seen stuff like this before, but lookit the crazy nuclear reactor!" Turning something on a manual lathe with no PPE is also dangerous. Bonus danger points for turning metals that make sparks/dust that might be harmful to inhale (hastelloy is nickel/chromium/molybdenum, which are not elements you really want in your lungs). But hey, at least nobody is wearing a tie! Those pictures of dudes in ties (and not clip-ons!) leaning over lathes turning boat prop shafts make me sweat. People were so damn crazy back then. Any time I consider doing something in an unsafe manner because it's convenient, I remember the phrase, "safety regulations are written in blood."

[@longboardfella5306]

As Beyond The Press channel says “safety is our third priority” lol

[@jeffcox4538]

What great history! Thank you Scotty! Amazing science.

[@chuckaddison5134]

Interesting video, I lived through most all of this and don't recall much of it ever getting into the news. But then when NASA publically announced that they were going to launch a reactor, there were demonstrations.

[@maigretus1]

"Critical geometry" Yes! Scott gets it! I studied nuclear power both in college and the Navy, and hearing someone say, "Critical mass," makes me cringe almost as much as hearing someone say, "Knots per hour."

[@Muonium1]

uh, critical mass is also an actual thing that is very important and in no way comparable to a redundancy like knots per hour

[@chrismofer]

​@@Muonium1but a critical mass in the shape of a sphere is different to the critical mass is the shapes actually used in reactors such as spaced out rods. It could very well be a critical mass but not a critical geometry.

[@Muonium1]

@chrismofer yes, obviously. But the latter doesn't negate the importance of the former. In other words the inverse cannot be true, you cannot have a critical geometry in the absence of a critical mass.

[@liam3284]

knots per hour, sounds like a rate of acceleration.

[@maigretus1]

@@liam3284 Technically, it is.

[@markedis5902]

I wouldn’t have wanted to be the bloke turning fuel rods on a lathe!

[@It_got_darK]

Great video as always scott. I'd like to add that hastelloy is an alloy of nickel and chromium (allong with some other stuff like iron and molybdenum). Fly safe

[@henrycarlson7514]

Interesting , Thank You

[@thomasdarcio7143]

IA image treatment is highly disturbing. Honestly, would have been FAR better to just put out a clean slideshow in there ....

[@chrismofer]

Would take the original frame rate and resolution of the scan every single time over AI hallucinations.

[@wattsmichaele]

Yeah…if it was real

[@somerandomnification]

I completely agree.

[@Ergzay]

The AI upscaling used in this made some of the people look like real horror monsters. Especially at around 6:10.

[@drupiROM]

The AI "enhanced" oldschoold footage looks way worse than it did originally. Great clip anyway !

[@RCAvhstape]

Scott, since you mentioned the Soviet spacecraft, maybe you can do a video on the one that crashed in Canada in the 70s and basically scattered its reactor core over the northern wilderness.

[@mfshill]

The upscaling/ai? on the old videos is really really bad. would have been better off leaving them as is.

[@johndododoe1411]

Needs a hard limiter keeping the output pixels within the absolute min/max range of the input pixels closest to each output pixel, with the limit triggering fed back to the NN as a strong error condition .

[@tmuiuocrndqs]

Please no more AI. Like, what's going on with that guy's finger at 12:10 ? What happened to the truss structures of the dishes at 11:30 and 11:34 ? Why is there a red section of the rocket at 10:02 ? It's also making all the text more illegible than it already was, and giving the faces and hands an unnatural "smoothness".

[@dwhite1940]

Hey thanks for the info, more than I ever knew. I worked at SLC4 for Lockheed at the time and spent many months preparing for the launch. Mostly I worked the ground telemetry systems and the SNAP was different than any other program, the telemetry as I recall was PAM instead of the usual at that time which was FM/FM with commutators. Lots of overtime. Lots of different sensors on the pad to make sure nothing was leaking and we all wore radiation badges. I was just a kid so fun for me. Thanks.

[@happysalesguy]

Wow, that was interesting!

[@bogdanivchenko3723]

this is probably the most advanced spacecraft ever built. I hope this footage wasn't fully AI Generated.

[@chrismofer]

No but AI upscaling never actually works well.

[@johannesgutsmiedl366]

welll the soviets launched 31 reactors that were 6x as powerful and used to power actual military missions instead of just serving as tech development platforms...

[@WWeronko]

They did have some real gonades back in the day. Today, not so much.

[@Jedward108]

Scott, here's a story idea. Tell us about telemetry and sensors used in spacecraft from the '50s to the present. I imagine the technology way back when was so much more limiting, but it would be fascinating to see what they measured and how they were able to send signals back to Earth.

[@ztyy8185]

Superb video Scott. I wish they select you for space mission

[@nwallace]

All the old footage looks like it has been up-scaled. Not a fan. I think I would rather watch the old low res stuff. Is it just me?

[@tomamberg5361]

If I remember correctly, a critical engineering goal for safe space-based reactors is robust encapsulation of the radioactive elements so that an accident on launch doesn't contaminate the launch area and beyond. Did this system have such "robust encapsulation", or did they just trust their launch system wouldn't blow up on the pad?

[@patreekotime4578]

I think the idea was that they wouldnt turn it on until it was in orbit. The base materials were safe enough for them to handle by hand apparently. And the size of the stack is too small to go into runaway by itself. It isnt until its up and running that it becomes a toxic radioactive waste machine.

[@Muonium1]

watch the video. the strategy was the antithesis of encapsulation, it was deliberately designed to totally burn up and spread contamination as diffusely as possible. Just like SNAP 9a did when its pound of plutonium reentered over the Indian Ocean in 1964.

[@placeholdername0000]

That is mainly a problem with RTGs, reactors generally don't have that problem.

[@davidponseigo8811]

My father was US Air Force Air Police attached to the Defense Atomic Support Agency and the Special Weapons Project and worked on the mission along with many others.

[@piranha031091]

3:00 : Hastelloy is a standard nickel-based superalloy, with chromium and molybdenum being the main alloying elements. It does not contain hafnium nor tungsten, as far as I'm aware.

[@douglaspeale9727]

That "resolution enhanced" old footage looks awful. Using unenhanced video would have been better. It is disturbing to see peoples faces distort like that.

[@tomarnd8724]

That AI upscale is horrible

[@Sonnell]

You think that because perhaps you did not see the original material.

[@tomarnd8724]

@@Sonnell I get that it would turn some people off, especially for a 100% voiceover video, but I still think it's bad that what is now surely the most seen and widely available version of this footage is tainted by an AI upscale

[@ivandemiguel8607]

I am confused, what is AI generated or modified?

[@RealBLAlley]

God forbid you pay attention to the information presented and actually learn something.

[@tomarnd8724]

@@ivandemiguel8607 the entire archive video of the reactor testing and assembly as well as the animations

[@tjairicciardi9747]

awesome video

[@calijoe1074]

I believe that the alloy "Hastelloy" is a trademark for one of the inconel alloys.

[@davidelliott5843]

Alvin Weinburg proved that molten salt as a nuclear fuel is not only self regulating it’s also extremely efficient and it burns 99% of the fissile components in the fuel. The waste has a 1/2 life of 30 years vs 30,000 years for traditional solid used fuel. It does not need a metal coolant so avoids the complexity and pollution hazards.

[@patreekotime4578]

Yeah but dont you need to get it up to a super high temperature and maintain it there? That seems difficult to maintain in something this small in the heat vacuum of space.

[@jeromethiel4323]

Molten salt thorium reactors are the future, and we already had that technology in the 60's. But we went with Uranium fueled reactors and fast breeders in order to make plutonium for atomic weapons. Funny how China and India are both researching this tech, and we sit here doing nothing with the tech we've already proven works. Not to mention the US has huge reserves of thorium... But hey, the politicians know best, right?

[@S1nwar]

2:13 I think the AI image enhancement you used gave the man GILLS behind his right ear or something^^

[@julieannepatterson3295]

this episode is gold. at 14:22 was one of the several times i had to 'stop 'rewind and hear that agai n!!!. serious mad ideas from science / inventors playing. strewth, cheers. great show. i do have a rocket engine topic you probably can explain real quick . Rocket engines Push, How is the push connected the structure? and then maintain vectoring?

[@Planetery_Dragon]

Amaziing video

[@arjunsairam5949]

nice video (Im still waiting for the skip ads button)

[@scottmanley]

I think KZbin wants you to pay for that

[@zebo-the-fat]

What ads? (using the Brave browser)

[@JPMadden]

This was back when the U.S. was still conducting nuclear tests as part of "Project Plowshare," one of the worst ideas in modern human history. The idea was to use nuclear explosions to excavate civilian construction projects. One proposed use was to expand an underground aquifer so that the then-irradiated water could be used to irrigate crops for human consumption. Others included using many bombs to dig second canals in Panama and Suez. Genius! Thankfully, they never did anything besides testing. I'm always mystified why it took humanity at least 20 years after 1945 to comprehend that nuclear fallout was unhealthy.

[@kenjohnson8751]

My father worked at this company, Atomics International, in Canoga Park, CA during this period. You can see the AI logo on some of the lab coats. It was a division of North American Aviation at the time and later merged with Rockwell to become North American Rockwell. I worked there as a summer intern for two summers in the late 70’s on my summer breaks from college, By coincidence occasionally getting to work with my dad in a professional capacity. It was a real highlight of my life.

[@gizmophoto3577]

I have a copy of an AEC brochure regarding the SNAP program from the mid-‘60s.

[@harlockmbb]

We would have weekends in Titan by now if America did not back away from this idea.

[@scifirealism5943]

There was an article on this. Called "trading existential opportunity for existential risk mitigation."

[@hadinossanosam4459]

Great video otherwise, but please please please don't use this AI upscaling again - the rocket at 7:58 or the people's faces at 6:05 made me _genuinely uncomfortable_ (in a body-horror kind of way)

[@TheEvilmooseofdoom]

So he has to adapt how he does things to accomodate your unique issues? That doesn't really seem reasonable.

[@TheAlchaemist]

9:14 Take that beautiful view of a huge diffusion vacuum pump on the left...

[@rablackauthor]

SNAP was developed at the Santa Susana Field Laboratory, at the eastern end of Simi Valley CA. The same place where they did static tests of the early rocket engines. It wasn't the only sodium-cooled reactor. There was also the "Sodium Reactor Experiment," a prototype for commercial nuclear power plants. That reactor did have an accident that released radioactive steam into the air (something people claim is still contaminating the area - who knew steam could stick around that long?).

[@liam3284]

Depends if there were heavy metals mixed with the steam. Tritium water will decay in not too long.