Deep Space Questions Episode 6 - Radiation Hardened Computers, Propellent Depots, Scary Rocket Fuels

[@666Tomato666]

"launch profiles, that's a boring subject" Scott, we're watching video about rocket science, no part of it is boring. Especially the parts that may lead to "you won't go to space today" scenarios.

[@catmate8358]

Agreed. I find it kinda fascinating that you can't go where you want in a rocket, depending on the latitude of the launch site.

[@flippert0]

I have to agree with Scott here, launch profiles are boring. Lunch profiles OTOH, now we are talking.

[@jab9934]

I would really like a Video about them!

[@HarryNicNicholas]

you get lunch at the restaurant at the end of the galaxy.

[@fluffly3606]

I like to daydream about scientifically accurate action (loose usage) scenes in my free time so launch profiles are definitely not boring for me

[@OCnStiggs]

The fuel topic made me laugh. When I was a kid in the late 70's, my Titan II ran on Aerozine 50 and unsymmetrical-dimethyl-hydrazine. Standing under the engines of fully loaded Titan II knowing there were thousands of gallons of liquid over your head that would melt you in seconds was uber sobering. Also, the knowledge that it was hypergolic and only separated by thin aluminum was another thought to ponder. Never mind the 9MT warhead on the upper part. It was a fun job while it lasted and I was only 25 when I left after three years.

[@oldfrend]

the thermonuclear warhead was probably the safest part of the stack for you!

[@makeracistsafraidagain]

The first time I was in the presence of a nuclear weapon I walked up and put my hand on it. After a few moments the guide said "everyone does that".

[@gsmontag]

Sobering to think about it, especially considering the incident in Damascus, Arkansas with a Titan II. It literally blew the lid off the launch silo.

[@unitedfools3493]

@@gsmontag Lunatics calling nuclear weapons "sobering" and "fun jobs" while voting to have them.

[@OCnStiggs]

@@unitedfools3493 When I was 25, I was the Combat Crew Commander of a nuclear missile crew stationed in a site, monitoring a missile located just down the hallway. I underwent a "little" psychological testing before being allowed to start training and endured constant monitoring under SAC by my Commanders and co-workers under the Personnel Reliability Program (PRP). I assure you I was the farthest thing from a "lunatic." What were you doing when you were 25?

[@sporkeh90]

"Chemistry can do neat stuff" - Scott Manley 2021

[@Jamesdavey358]

Yes, yes it can

[@catfish552]

[@SuperMonkei]

"For science" Scott Manley 2014

[@beanieteamie7435]

Jessie, we need to cook.

[@PercivalBlakeney]

@@beanieteamie7435 Y'beat me to it. Yeah Science! 😁

[@danielculver2209]

3:27 The Martian atmosphere is primarily carbon dioxide (freezes -80°C at standard pressure). Vacuum insulation works great until it gets punctured, then the latent heat released by solidifying carbon dioxide could quickly boil off your tank. The relief valve is necessarily uninsulated, so it may be covered in a thick layer of dry ice already. I would suggest installing two rupture disks in series with low-pressure helium between them, and of course a pressure indicator to verify that the helium is still there and hasn't gone off to explore the Martian surface.

[@mxg75]

I see FOOF in the thumbnail and know this is going to be an energetic video. It’d be a very good rocket oxidizer if it didn’t threaten to oxidize the entire rocket.

[@cezarcatalin1406]

Are we even going to talk about methyl mercury ? That thing is so bad that no chemist wishes to work with it... and methyl cadmium is even worse somehow.

[@Dragrath1]

@@cezarcatalin1406 While no sane human would work with it anaerobic microbes convert other forms of mercury into methyl mercury so technically with the right engineering you might be able to cut the human aspect (though ideally you would never use that shit on or near Earth or any other planet we ever planed to colonize/terraform lol.

[@dborne]

@@kukuc96 That quote was for Chlorine trifluoride - yet another wonderful molecule jam packed with fluorine atoms for your entertainment.

[@antonystringfellow5152]

I think the greatest oxidiser of all is chlorine trifluoride. I know this much... is sets fire to such materials as glass and concrete, on contact.

[@Shaun_Jones]

@@antonystringfellow5152 it will also light up asbestos and ash.

[@ericpaul4575]

Also on Titan you could have a camping stove with a O2 bottle as your “fuel” source.

[@AllonKirtchik]

What does a flame like that look like? (In an environment with reversed fuel/oxygen presence)

[@davidanalyst671]

@@AllonKirtchik it looks like fire

[@Justsomeoneyoucouldhaveknown]

8:15 Sound like a perfect idea for a time capsule. Take some things, put it in a can, seal it and send it on a long, elliptical orbit through deep space/outer planets. Presumably on a safe orbit that would leave it linking up with Earth in like 500 years time. If we really wanted to, we could give our descendants quite a shock by making it look like some kind of space ship from a lost civilization. Of course keeping it simple will probably work just as well.

[@kasuha]

Regarding Lagrangian points, you're forgetting that they orbit along with the smaller body. L1 is NOT where Sun's and Earth's gravity balances out. It's point where Earth's gravity reduces Sun's gravity just enough so you can orbit Sun at orbital speed with angular velocity equal to Earth's. Similar thing with L2.

[@Keithustus]

Yes, not the greatest explanation from Scott in this one. Definitely would be a good video topic on its own. Sadly we won’t see them in KSP2....they said it would be too intensive for CPUs to have to deal with n-body positions while also controlling rockets and things.

[@NavidIsANoob]

Yes, Principia allows for n-body physics, but it also proves their point about performance. Having too many active spacecraft in Principia will tank your performance.

[@DrWhom]

OK, but that means you can hold steady relative to Earth, right?

[@neiljopling4693]

It is easier to spot the difference at higher eccentricities.

[@AldorEricsson]

Lagrange points ARE the points where gravity balances out if you look at them in the frame of reference co-rotating with the orbiting bodies. In that frame of reference, both Sun, Earth and a satellite placed at any Langarge point will be at rest.

[@ashemgold]

This guy says more interesting & sensible stuff about rockets / space than I've cumulatively thought in my (over 50 year) lifetime. Thanks Scott. Keep it up.

[@MatthijsvanDuin]

15:40 The great book Ignition! includes a story of him getting a request from higher-up to try firing dimethylmercury in an engine (with RFNA), but when he called his supplier to ask if they could make him *a hundred pounds* of the stuff he heard a "horrified gasp" from the other end of the phone line and the supplier politely declined and hung up. Disturbingly, the idea of using mercury in an engine (to achieve high impulse density, for situations where physical space is more at a premium than weight) did not end there. To satisfy the request he wrote up a concept using liquid mercury injected into a liquid monopropellant engine, expecting to "see it bounce back in a week with a "Who do you think you're kidding?" letter attached". It didn't. They were directed to proceed with experimental verification and they now had to figure out how to test-fire this horrifying thing while collecting and scrubbing the exhaust to avoid giving everyone in the county mercury poisoning. In the end, before they got around to test-firing it the Naval Air Rocket Test Station (where this was taking place) was shut down and they were ordered to ship the setup to the Naval Ordnance Test Station (NOTS). "With a sigh of relief, we complied, and handed them the wet baby. Saved by the bell!" In the end NOTS did in fact fire it (in the middle of the desert, without bothering with exhaust scrubbing) with a bipropellent (UDMH+RFNA) rather than monopropellent engine, and it performed close to theoretical calculations. The project was declared a technical success, and never touched again with a ten foot pole.

[@Intelwinsbigly]

Dimethylmercury in a rocket, dear god.

[@HalNordmann]

Somebody thought of substituting it with ethylmercury - could that work, and would it be safer?

[@Artemis-zl5cs]

Good _god_ . The early days of rocketry were a truly wild time.

[@MatthijsvanDuin]

@@HalNordmann I mean, safer than dimethylmercury? Probably, that's a pretty low bar to set. Elemental mercury is definitely much safer to handle than either of those though. Of course this only pertains to the safety of handling the "fuel", the rocket exhaust will be equally toxic and environmentally catastrophic regardless of what form the mercury was in originally.

[@HalNordmann]

@@MatthijsvanDuin Yeah, it's not good either way. Not that I like any of these fuels anyway.

[@infinitelyexplosive4131]

Nitpick: The 14/10/7/5nm designation does _not_ refer to a specific feature size. It is used to express a ~2x increase in transistor density (sqrt(2) reduction in side length => 2 reduction in density), but there are different types of transistors and non-transistor features on a chip, so the terms end up being mostly marketing for the different companies.

[@mccellenlol4163]

Lol. I never thought I’d get poop jokes on this page. Gotta say. I’m not disappointed. 🤣

[@-danR]

I think Scottish püp is probably more manly püp.

[@MrGoesBoom]

it might be meant as a joke, but that tweet and it's responses sound like it COULD be spun into an interesting plot, if done right. Not Bestseller or Hollywood Blockbuster material, but still a bit interesting. Just for the historical spaceflight aspects you could shove in there.

[@bedlamite42]

Happens every time a probe heads toward Uranus

[@damientonkin]

You've clearly never read the Apollo 10 transcripts.

[@RandomName-do2gm]

There is a whole video on this topic called 'Space Poop Challenge'. Pretty funny

[@18robsmith]

For the "greatest" liquid propellants one should get hold of a copy of "Ignite!" by John D. Clark. Some of those mixtures would make even Scott's hair curl

[@jamesharmer9293]

It was reprinted a few years ago. I got a copy from Amazon. Interesting and also funny.

[@chriskerwin3904]

Pentaborane is the way

[@-danR]

@@jamesharmer9293 Ignition There's a PDF as well. I've got it downloaded somewhere.

[@-danR]

sciencemadness d0tt org sIash library sIashbooks sIash ignition d0tt pea dee eff (

[@bernarrcoletta7419]

Scott did an episode a while back where he talks about “Ignition”.

[@albertjackinson]

You can tell Scott is having so much fun recording these episodes and talking about this. I love it. Nerdiness rules!

[@grandpamao7271]

Scott Manley: I don’t see Jupiter as a place humans can colonize Issac Arthur: Hold my drink and snack

[@makeracistsafraidagain]

My favorite channel.

[@ImieNazwiskoOK]

What about vacuum balloons? And if they hat strong hydrogen balloon at some point "air" will be more dense.

[@ultimaIXultima]

And don't forget to turn on the subtitles. ;)

[@Skinflaps_Meatslapper]

@@ImieNazwiskoOK If vacuum balloons were within the scope of feasibility, we'd be using them here today, as running a vacuum pump is far cheaper than sourcing massive amounts of helium and also much safer than using hydrogen. Plus, you wouldn't need to bring additional lift gas with you in case of a leak or membrane diffusion, just some power to run the vacuum pump as needed. In theory, a vacuum balloon is far superior to a lift gas balloon, but practically speaking it's beyond our current abilities. Getting a large enough structure to hold a vacuum that's also light enough to make use of that buoyancy displacement would require some pretty exotic materials. A vacuum balloon would require this material to withstand a constant state of compressive force, rather than the tensile force of a traditional balloon, and most materials that are light enough for this type of task are far stronger in tensile than compressive. So you're essentially talking of a worst possible scenario across multiple points in engineering terms, but say you did manage to get one to work on Jupiter...what would that be like? For one, your craft is not going to be buoyant on the top of the hydrogen atmosphere, you won't be sitting above the clouds enjoying the view. You're going to be buried in the clouds, perhaps miles, because even though you're just barely more buoyant than hydrogen, you still need to be in it to be buoyant. The hydrogen is going to be super thin for that initial atmosphere, and you likely won't be buoyant enough to stay right on the edge, and the additional gravity is going to make the rest of your craft less buoyant than you'd like. An example of this is the max altitude of a lightly loaded weather balloon compared to a heavily loaded weather balloon, the more lift you need to sustain buoyancy, the deeper into the atmosphere you have to go in order to achieve buoyancy. Now that we've established our exotic vacuum balloon is already going to be miles deep in the atmosphere on a good day, one need only look at the tremendous weather patterns and winds on Jupiter to get a sense of why we don't want to be miles deep in an atmosphere containing hurricanes the size of earth and shearing wind patterns with speeds approaching 900mph, possibly containing corrosive ammonia thrown up from those violent winds. And then you have to contend with the fact that the gravity you will experience is 2.4x that of earth, which would make even the simplest of tasks difficult...you'd spend most of your time laying down because you wouldn't have the energy to stand or walk for more than a short duration. It just seems like a whole lot of work to me for very little payoff.

[@ImieNazwiskoOK]

@@Skinflaps_Meatslapper For humans it wouldn't be great, but maybe for atmospheric reaserch. For Earth this idea sucks, not sure about Jupiter, but it could be good for planets like Mars. (and being possibly good for Mars is something that even NASA says)

[@LorneChrones]

Additional radiation hardnening techniques: Triple module redundancy with voting circuits between the three redundant systems. Additional memory technologies that are radiation tolerant/hardnened: FeRAM and MRAM. Both of which aren't reliant upon electric charge to store information and thus inherently immune/resistant to ionizing radiation. Also adding shielding to electronics or even using so called "guard-bands" that go around the individual transistors that contain induced charges from ionizing radiation (e.g. the induced charge doesn't leak from one transistor to another with the insulative guard bands).

[@EricMKE]

Accelerando by Charles Stross is one of my favorite books. I'm glad to hear him name dropped.

[@randombloke82]

My favourite non-traditional oxidiser is high purity hydrogen peroxide. Not only is it a good oxidiser, it can be used as a monopropellant for both RCS and turbopumps. Even better, the catalytic breakdown products from the turbopumps can be injected directly into the combustion chamber because they still contain high temperature oxygen. Oh, and it can be stored at room temperature.

[@HalNordmann]

It is also much less toxic/corrosive than hydrazine, and also hypergolic with hydrocarbons when ran over a catalyst. This is the reason why it is used as storable chemical monoprop/oxidizer in my stories.

[@Paul_Ch52]

You do this Q&A stuff well. Various topics with lots of info. Thank you.

[@apalrd8588]

A surprisingly large amount of military/aerospace equipment still relies on old-fashioned 54 series (military version of 74 series) individual logic gates and analog components in their control circuitry, without using microprocessors at all. Part of this is carryover designs from decades ago, but also because a lot of those components are available 'easily' in rad-hard versions. It's a fun topic to dive into, and it's interesting how far they will go to avoid microprocessors when dealing with high radiation environments.

[@BrianJacobson]

I would love a deep dive on JWST orbit mechanics. I learned this week that it is actually orbiting the Lagrange point rather than resting in it and I would love to understand how that works.

[@aatsiii]

I'm not a rocket scientist, but maybe you misunderstood or someone misrepresented to you how things are. All of the points are still orbiting the Sun, they are just stable and stationary related to Earth.

[@BrianJacobson]

@@aatsiii go watch the NASA videos about it. They are very explicit

[@jmr5125]

Some of the Lagrange points have a "virtual" gravity well at / near the actual point. If you adopt a frame of reference is the Lagrange point, the motion of the spacecraft in the area *acts* in all respects (including mathematical) as if it were near a gravity well. Tl;dr: have you had a debate about centripedial vs centrifugal forces? Same thing, just about gravity instead of inertia.

[@Keithustus]

@@aatsiii probably a lot of misrepresentation. I’ve read some stories (about James Webb maybe?) indicating that the instruments at and planned to be at the stable L points would be orbiting them and not precisely at them. I interpret that to mean that if a device is incredibly close to a point, it can have its velocity set to match such that it circles it like a pendulum. Otherwise it would only be possible to have one satellite at each point.

[@BrianJacobson]

@@jmr5125 thanks for the explanation. I'll see if I can find some more in depth explanations on it so I can better wrap my mind around it.

[@Cannabian]

One of the things to keep in mind with new CPU is when they say its a 2nm, 5nm, or 7nm process etc that actually isn't describing the size of anything on the chip. We've gone 3D in chips and stack transistors now, so when it goes from 5nm to 2nm it's describing the performance increase IF you shrunk the transistor. But we don't shrink anymore, we just add more layers or make layers better designed.

[@DrWhom]

I did not know this

[@MichaelCoombes776]

Yep, it's got to the size where shrinking transistors further would lead to quantum tunneling becomes more and more problematic and electrons just "ignore" the gates, leading to errors. IIRC quantum tunneling happens at all node sizes, it's just rare enough that error correction systems can work around it. Much more shrinking and that won't work.

[@canadianragin]

Wow, I was going to suggest “A Tall Tail” to you - thanks for covering it!

[@HalNordmann]

I think it might've been me who suggested it. The scientist who has proposed those weird combinations and laments over not using them, while ignoring the obvious risks reminds me of some Project Orion fans.

[@Lucius_Chiaraviglio]

A problem with things like FOOF and dimethylmercury, even if you got past the toxicity worries, is that they are heavy. You get more energy per molecule than with hydrogen-oxygen, but less energy per gram. Just to keep things simple, think of hydrogen-fluorine (H[2] + F[2] --> 2HF) compared to hydrogen-oxygen (2H[2] + O[2] --> 2H[2]O). (Looking this up on the Wikipedia chemical bond data page, but it looks almost the same as my college organic chemistry book's table from 1980.) The hydrogen-fluorine bond has an energy of 568 kJ/mole (you make 2 of these), and the hydrogen-hydrogen bond has an energy of 435 kJ/mole (you break one of these), while the fluorine-fluorine bond has an energy of 158 kJ/mole (you break one of these). Net energy release is 543 kJ/mole of fluorine (or mole of hydrogen). The hydrogen-oxygen bond has an energy of 467 kJ/mole (you make 4 of these); the oxygen-oxygen bond in an oxygen molecule (which is very different from an oxygen-oxygen bond in a peroxide) has an energy of 495 kJ/mole (you break 1 of these) (and you break 2 hydrogen-hydrogen bonds at 435 kJ/mole as noted before). Net energy release is 503 kJ/mole of oxygen. So using 1 mole of fluorine to burn hydrogen does make more energy, but weighs 40.01 g (2 moles of hydrogen fluoride), whereas using 1 mole of oxygen to burn hydrogen weighs 36.03 g (2 moles of water). Energy to mass ratio for hydrogen-fluorine is 543 kJ/mole / 40.01 g/mole = 13.57 kJ/g. Energy to mass ratio for hydrogen-oxygen is 503 kJ/mole / 36.03 g/mole = 13.96 kJ/g. So hydrogen-oxygen is actually the better rocket fuel than hydrogen-fluorine. Unfortunately, while the above-mentioned data table gives a strength for an oxygen-oxygen peroxide bond (146 kJ/mole), it doesn't have the strength for an oxygen-fluorine bond (and I don't think my 1980 organic chemistry textbook does either), but it is reasonably probably somewhere in between the oxygen-oxygen peroxide bond and the fluorine-fluorine bond -- split the difference and call it 152 kJ/mole (and remember that this leaves plenty of energy to drive FOOF to decompose back into oxygen and fluorine even at -100 `C, because when that happens you get back the much stronger oxygen-oxygen bond of the oxygen molecule). So if you use 1 mole of FOOF to burn hydrogen to make a mixture of hydrogen fluoride and water (3H[2] + FOOF --> 2HF + 2H[2]O), you break 2 oxygen-fluorine bonds (estimated 152 kJ/mole), 1 oxygen-oxygen peroxide bond (146 kJ/mole), and 3 hydrogen-hydrogen bonds (435 kJ/mole), and you make 2 hydrogen-fluorine bonds (568 kJ/mole) and 4 hydrogen-oxygen bonds (495 kJ/mole). Net energy for hydrogen-FOOF release is 1361 kJ/mole; total molecular weight (2 hydrogen fluoride + 2 water) is 76.04 g/mole. Energy release by weight for hydrogen-FOOF is 17.9 kJ/g, which is noticeably better than hydrogen-oxygen, but it's not clear if it is enough better to be worth all the trouble. And then we get to mercury. I don't have bond energies for anything including mercury, but I can look up the fact that the average atomic weight of mercury is 200.592 g/mole, and you can only get 2 mercury-fluorine bonds with release of energy, and the mercury-fluorine bonds aren't going to be THAT much stronger than hydrogen-fluorine bonds (and mercury-oxygen bonds are positively _wimpy_ -- mercuric oxide decomposes at only a few hundred degrees centigrade). (Somebody figured out a way to cram 4 atoms of fluorine onto each mercury atom, but this _requires_ energy, and the resulting compound is only metastable in frozen argon.) So DITCH IT. Nothing including mercury in any stoichiometric quantity is going to be any good as a rocket fuel, even if you had absolutely no worries about the toxicity. Using a mercury compound for a rocket fuel would be like trying to build an electric rocket powered by lead-acid batteries -- it just isn't going to work.

[@tomstiff9384]

"The Clouds of Titan". Sounds like a Niven or Heinlein story.

[@macblastoff7700]

I thought exactly the same the first time I heard that phrase.

[@DrWhom]

there is The Sirens of Titan by Vonnegut.

[@erbenton07]

No smoking!

[@rogerstone3068]

@@DrWhom Scott is sitting in a chrono-synclastic infundibulum; that's how he knows all the answers.

[@MatthijsvanDuin]

19:00 Correction: *thick* not thin. High density along with low gravity is what makes flying easy. If only it weren't so obnoxiously cold (but then again that's a big part of the reason the atmosphere is so dense anyway).

[@jackyboi8832]

Hi Scott I am always really excited for when you upload

[@gustavderkits8433]

Rad hardened processors cost a lot more. A NASA expert, told me, “ there’s a reason the boards we use cost two hundred thousand dollars”, and that’s for less processing power. Radiation is the most difficult problem for space travel in the long run.

[@Grimsace]

Fyi the 5nm size is a bit of a misnomer, most modern architectures are based on a 14nm process that is stacked into multiple layers to give what is effectively a 5nm transistor size when all of the transistors are placed directly next to one another on the silicon die. The actual smallest features are thus still 14 nm. I'm not an expert on this but Dr. Ian Cutress (TechTechPotato on KZbin) does a great job explaining this.

[@dcchillin4687]

I'd love an episode with more in depth info on computer hardware in space!

[@seionne85]

More likes than seconds since release. That's good to see!

[@lucas29476]

Ah it's now 8 minutes but only 6 minutes of likes :(

[@seionne85]

@@lucas29476 darn we're slacking lol

[@Rorr59]

I don't know why but I really like the way you explain everything, even if I don't have enough science background to understand it all, it's interesting and I think I get a little more from each video.

[@d4rk0v3]

Insulating against the cold on Titan with such a dense atmosphere would be a nightmare. The thermal conductivity of the atmosphere on Titan is higher than on Earth. You would need an incredibly beefy suit to protect against that kind of cold. Your structures would have to be vacuum insulated. We're talking about a planet that averages -182.5c (-296F). You're going to have to build habitats, vehicles, suits and materials that will survive a cryogenic atmosphere. It is way harder than a lot of people seem to think. Insulating against a vacuum is easy. Vacuums have the worst thermal conductivity. An atmosphere with a surface density 1.5 times that of our own? Much, *MUCH* harder.

[@TraditionalAnglican]

So, you practice on places like the moon, Mars, Near Earth Asteroids, the Asteroid Belt & the moons of Jupiter. I don’t see humans trying to land or live on Titan until we’ve successfully lived on the moon/Mars, 2 or 3 asteroids & at least 1 of the moons of Jupiter.

[@d4rk0v3]

​@@TraditionalAnglican It's easier to insulate against the cold on the moon, Mars and anything with little to no atmosphere. I can't stress enough just how difficult it will be to build stuff that can tolerate 24/7 cryogenic freezing. We would have to have substantial nuclear power infrastructure on Titan to generate the heat needed to protect habitats. Then there's the problem with the compromising of structural integrity of materials that cryogenic cooling causes. You are right in that it would be one of the last places we put down. We would have to have the interplanetary spacecraft support capable of extremely rapid development of the heating power infrastructure needed to support habitats on Titan. It just drives me nuts every time I hear someone underestimate the cold factor especially when they design the protective suits people would be wearing. They would need to be more substantial than space EVA suits. Be made of a material that can remain flexible at cryogenic temperatures etc etc.

[@michaelmoorrees3585]

Back in the mid 80s, Harris made rad hardened 80C86 processors. They increased the noise margin by operating the processors at 10V, as opposed to 5V. So the components had to be modified to work at 10V, as 7V was usually the absolute maximum value. Probes launched as late as the late 90s, still used those.

[@rppvt]

I'd love to see you speculate on the interior of the new Chinese Space Station and get your opinion on their equipment/design.

[@DrWhom]

I think they have tiles everywhere so it is extra loud. (The Chinese like their public places as noisy as possible, which is related to the idea that the clamour of human conviviality scares off evil spirits.)

[@AsbestosMuffins]

I remember reading an article at my last job when we got these aerospace journals, there was a company claiming they could avoid the bit flip problem by using just many more error correcting elements by using newer, but not radiation hardened equipment since they'd get a big processing, speed, and power boost while being able to package like 5x the hardware in the same space. Basically trying to correct the errors faster than they occur

[@unitedfools3493]

I don't know what you are reading but we are talking about errors that happen rarely and they are easily corrected by error routines.

[@tenns]

if it's 200 vs 5 nm feature size and it does work like you said, then it's 40x not 400x, and you do get 1600x Scott basically did two math mistakes that cancelled out LIVE, now that's the kind of things i like

[@Pongant]

Great Scott, I wanted to quickly thank you for your work on YT. You reignited my interest in space when KSP was gaining traction. You also inspired me to push my research career (what a dead end that is!) to a more programming-oriented professions. Thank you.

[@jimmypalavi]

Fantastic episode Scott! Love this occasional format. Is flammability of the environment on Titan a concern? Lakes of liquid ethane or methane and their vapors seem like risky objects to fuel and ignite propulsion systems near, but then again between the cold temps and lack of oxygen perhaps it's not a concern? Thanks so much!

[@the-programing]

Love these videos. Just an addition, on earth oxygen is kept liquid by having high pressure, which makes the the boiling point higher. Since oxygen boils in air on normal earth temps, the pressure of a cryogenic oxygen tank is kept high as oxygen boils on top of added pressure.

[@Necro3Monk]

Jupiter Balloons: You could use balloons on Jupiter, since the atmosphere has a good fraction of helium in it, pure hydrogen would float. Though it would be a gigantic balloon. Having read Ignition like most people here, FOOF/acetylene seems a good backup for a crazy combination. High performance, easy ignition, destroys your rocket from normal use so no one can steal it...

[@666Tomato666]

Sounds like something you'd use in a Footfall scenario.

[@jimirving3235]

In the 80's I worked for the DoD's Reliability Analysis Center, which did groundbreaking forensics on failed aerospace microchips leading to critical static suppression/mitigation design improvements. Radiation hardening for space sounds sort of similar - but, of course, it would be tough to get back failed chips for analysis.

[@WiztotheIzzard]

Dioxygen difluoride - One of the few chemical composition onomatopoeias.

[@Richardincancale]

One of the very first microprocessors - the RCA COSMAC CPD1802 was produced in a radiation hardened version (silicon on sapphire) and is still being produced today by Renesas. First shipped in 1976 so 45 years in production!

[@bretzel30000]

can you do a computer programming in space video sometimes? with the coding guidelines etc. necessary for code that runs on space hardware? i know that video is going to be very niche, but interessting nontheless!

[@EVEeeq]

mars ingenuity's software is opensource on github, and i believe its mostly c++

[@SoloRenegade]

Some software on the ISS has been Linux based.

[@jc6558]

How coding for space (mission critical stuff) is? 1 line of code per day per engineer… let that sink in.

[@owensmith7530]

@@jc6558 Hmm, even in commercial programming if averaged over my entire working hours (meetings, writing documents etc as well as coding) I'm not convinced I'm above 10 lines of code per day.

[@dale116dot7]

@@owensmith7530 Automotive programmer here (engine controls). I would say probably 4 to 5 lines per day, adding ISO 26262 to the software mix adds a level of review and testing.

[@mikerichards6065]

The fictional story about making an adversary try to tame FOOF in order to slow them down sounds like it might have been inspired by Concorde versus the Tu-144. The story goes that French intelligence learned that the KGB was sniffing around Michelin. Concorde was not only much heavier than other supersonic planes, but had to make much faster takeoffs and landings than other airliners - and do it on a regular basis. Michelin had come up with a synthetic rubber capable of the job and the Soviets wanted something similar for the Tu-144. Rather than roll-up the espionage ring, French intelligence got Michelin to cook up another rubber formula which had a consistency more like bubblegum - and leaked that to the Soviets. History doesn't say if the Soviet Union's supersonic airliner was ever firmly stuck to the runway...

[@headcrab4090]

You misspoke when you said the atmosphere on Titan is so thin. 1.45 atm. Gravity 0.138 G. So flapping muscle powered wings would work :)

[@rdizzy1]

It would prolly be similar to swimming in the ocean with flippers on.

[@fromagefrizzbizz9377]

@@rdizzy1 It’d be a little thicker than air but nowhere near as “fly able” as water. This is equivalent to a hyperbaric chamber set for pressure balance with water pressure at only 16 foot depth. I’ve been in a hyperbaric chamber at 160 foot depth (5 atm above sea level pressure) and flapping your arms just make you giggle from the Martini law. It’s apparently barely possible for man to fly at 1atm pressure with 1/6th earth gravity- but would require extreme effort. Might be a bit easier on Titan. Using “wings” of course

[@rdizzy1]

@@fromagefrizzbizz9377 Ah, I see, still seems to make flying in general far easier. I figured with such low gravity combined with this that the air would have higher buoyancy like a helium balloon on earth.

[@MarsJenkar]

@@rdizzy1 Yeah, Randall Munroe (of xkcd fame) pegged Titan as the one world in this solar system that might be easier to fly a Cessna in than Earth itself, at least for a while.

[@fromagefrizzbizz9377]

@@rdizzy1 Still nowhere near as buoyant as a helium balloon. My posting was intending to say that you wouldn't even notice a 50% increase in air pressure (air is mostly nitrogen, so an increase in pressure of pure nitrogen is only marginally different from air) except insofar as your "glide range" (say a hang glider or a wingsuit) would be a *bit* further, but you'd essentially be no further ahead with strap on wings at generating lift. In fact, the lift of a helium balloon would be approximately the same at 1atm and 1.5atm, whether the environment is air or pure nitrogen. The key to "flight" is the reduced gravity - on the moon 1/6th of earth, and on Titan about 1/7th. As I said, it is believed that very fit people on the moon *could* actually rise using some sort of human powered wings on their arms, but only for short times (a few minutes at most). On Titan it would be a trifle easier because the gravity is even less. Glider wings are likely to become a popular sport on the moon if we ever build structures large enough for them. On Titan, you could do it "outdoors". But flying like a bird? A couple minutes at most. it's all about the human body overcoming gravity, the density (short of stupidly high pressures, or a liquid) matters little.

[@onedeadsaint]

9:19 as a long time viewer, that felt like a great payoff! lol made me smile at least cheers!

[@MD.ImNoScientician]

Can you give us a deep dive into the SpaceX Starlink satelite deployment and propulsion systems? Is this information common knowledge? I'm wondering how much material is turned into space Junk too.

[@sylvialiu7907]

3 weeks ago????????????????????????

[@VikingCuda]

@@sylvialiu7907 You probably don't support Scott Manley on Patreon.

[@kyleduvenage5863]

How is this three weeks ago?

[@filegrabber1]

Pretty sure every starlink sat will de-orbit, like every other low orbit satellite.

[@VikingCuda]

@@kyleduvenage5863 You probably don't support Scott Manley on Patreon.

[@joshua20199]

Wow, I guess your explanation and a few very interesting top comments prompted Veritasium's latest vid about how cosmic radiation affects computers. Great topic!

[@edgeeffect]

I would like to recover the Apollo 10 LEM so we could do some genetic tests on the mystery floating poop.... and finally determine who did it.

[@bcikablam3578]

he basically said that exact thing in his video on it

[@edgeeffect]

@@bcikablam3578 that's because this is a vitally important question that NEEDS answers.

[@bcikablam3578]

@@edgeeffect I agree

[@jeffingram8279]

It’s always nice when you looking at KZbin videos going they all look ugh! Then you see Scott Manley has dropped a video and then its Oh hell yeah!!

[@Cliffdog01]

Do the L points get messed up by the other Planets, or are they balanced to take them into account like does Venus mess up L1 every now and then?

[@nicosmind3]

Id imagine there would be the odd tug, and thats why they go up their with fuel. Saying that Jupiter and Saturn have Trojen asteroids sitting at 2 of their points that have been there since the solar systems formation. But even saying that, Earth, Venus, and Mars dont seem to be able to keep hold of our asteroids, they only seem to be temporary So yeah probably :P

[@sphaera2520]

Afaik spacecraft at lagrange points don’t literally sit at the exact location, perfectly motionless. They slowly orbit around it much like how you would orbit around a very small asteroid with weak gravity. If done correctly, minor perturbations won’t really be a problem as it might change characteristics of the orbit but generally you’ll still be going around the point. If and when significant deviations arise, I’d imagine that is when fuel is spent to return it to the appropriate margins.

[@trimeta]

The theoretical math behind the Lagrange points assumes no other bodies, just the two large bodies and the small one you're trying to place in a stable point relative to those two. In practice, L1, L2, and L3 are unstable, in that slight perturbations in certain directions (which could be caused by another body, like Venus in your example) will compound and throw the spacecraft out of the Lagrange point. To solve this, the spacecraft have thrusters they use for station-keeping.

[@DrWhom]

@@trimeta I imagine Jupiter is always going to be the main one, even with it being much further away than Venus.

[@michac.8283]

I'm really enjoying these videos, educational and entertaining. Keep it up!

[@fatallotion878]

Nice mug Scott!

[@kamikazejs950]

I once worked for an engineering firm in Salt Lake City a long time ago. Back in the late '90's they had a bunch of very expensive SGI (Silicon Graphics) workstations that kept getting huge numbers of bit flips in their DRAM which would cause problems for the long-running simulations we ran there. SGI would replace the RAM and test it back in Mountain View, CA (near San Jose @ sea level) and the DRAM sticks would be perfectly fine, then ship good ones to us in SLC and the bit flips would start right up again. This went on for quite a while until SGI figured out that the much greater (or more energetic?) atmospheric radiation flux at 4600' was _just_ enough to cause problems for the DRAM modules. They did a bunch of testing and switched to ones that were more radiation-hardened and the problems went away. I got a lot mileage over the years out of telling that story to people when cautioning them to keep an open mind about sources of error and failures in complex systems!

[@bigjohn697791]

I know surrey satellite's use of the shelf stuff from chatting to a friend at the Guildford university that works for them

[@jtjames79]

Huge advantage for Starlink is the ability to use off the shelf. They are relatively low, and redundancy is vastly cheaper than resiliency in every relevant metric. Planned obsolescence isn't a bug it's a feature.

[@Zadster]

Surrey (SSTL) started out by making amateur radio satellites, tiny tiny budgets and relying on goodwill from engineers. Which is easy once they find out you are doing really cool engineering projects. This is a great way to find how to optimise budgets and work out what commercial gear works in nasty environments!

[@TomaszDurlej]

Fun fact, down on earth we also using radiation hardened processors. We using it mainly in medical industry (or other critical systems). Not so protected as in space but still. It’s mainly only steeplock (every operation is computed two times by two cores with small different time and compared). It is used to prevent errors happening because of different external distortions, space radiation among others.

[@undefined40]

Regarding the question which Moon to put people on next: Remember to stay away from Europa.

[@alexlandherr]

I really like these viewer questions videos Scott, more please!

[@jedimastersterling1]

"I don't think gas giants will ever be candidates for habitation" Clearly you've not seen Issac Arthur.

[@dsdy1205]

Even barring Isaac Arthur megastructures, Saturn could probably be inhabited by the same types of blimps you'd use to colonise Venus in the early stages.

[@Dragrath1]

@@dsdy1205I don't think gas giant blimps can be compared to Venus even if the physical principals are the same the conditions are so divergent that the comparison is too divergent. As to make a buoyant blimp in a gas giant like Saturn so far from the Sun you would have to have the nuclear reactors to keep that hydrogen sufficiently hot to compensate for the weight of the habitable compartment and or research equipment. And lets not forget that Hydrogen gas is notoriously hard to contain as its "small" size allows it to slip through most materials as if they weren't even there with the few things that do contain it still liable to leakage because hydrogen has the tendency to quantum tunnel its way through barriers. And need we mention Saturnian weather? With the planets strong seasons and the actively increasing axial tilt over the last billion years ongoing as the denser inner ring particles constantly rain down in a relentless shower of material and lighter outer ring accreted moons rapidly recede from Saturn. Did I mention that Saturn's system has the highest rate of impacts in the solar system? Evidence indicates that the inner Moons of Saturn from the small actively accreting "shepherd moons, to "Mimas, Enceladus, Tethys (and its trojan sibling moons doomed to collide eventually) Dione, Rhea & Titan not to mention probably Hyperion and Iapetus given that these moons orbits are all either dynamically unstable and visibly receding from Saturn via tidal interactions. The system or rings and moons is now thought to only be a billion years old at most with the process of moon formation from ring particles being an ongoing process analogous to the giant impact to heavy bombardment period in the solar system's evolution in other words all the impacts that made Mimas death star model happened in the that interval of time. It also seems likely that major impacts may be the main heat source for Enceladus's active geological activity. Needless to say it seems Saturn's system is a shockingly dynamic place more than we ever thought was possible which in terms of long lasting bases isn't a good thing. These conditions are noticeably quite unlike the conditions for blimps in the upper Venusian atmosphere where the lifting gas is an Earthlike nitrogen argon and oxygen atmosphere at or near thermal equilibrium with the environment that can double as crew quarters meaning you don't need to have a separate habitable cabin from the blimp. And better yet there isn't a constant stream of orbital debris raining down all the time. Sure there isn't a magnetosphere but you still have a protective atmosphere around you meaning the radiation environment is safer than the Moon or Mars where underground is the only option. Of course the atmosphere there is also fast and chaotic but much more manageably so compared to a gas giant with their huge internal heat sources.

[@dsdy1205]

@@Dragrath1 Ah yes, I forgot that Saturn had a hydrogen atmosphere. Uranus / Neptune maybe?

[@Dragrath1]

@@dsdy1205 Possibly the two Ice giant planets do still have a Hydrogen Helium envelope but its "only" a few Earth masses worth of gas. Beneath that its thought water methane ammonia and hydrogen sulfide should be the main constituents of the bulk of the planets material but at what pressure and chase those layers will be is a more open question. That said below the lower atmosphere there should be a global ocean which at depth transitions to much more exotic states of matter like superionic water before even deeper you get crazy stuff like decomposition of chemicals into their atomic constituents under extreme pressures. So worst comes to worst you should be able to make something able to float on the planets vast global oceans just it will be a question of whether you can handle the pressures involved that deep. In principal though under the right conditions you could hypothetically have habitable conditions for microbes down there given that life especially unicellular life does well in high pressures so long as liquid water can still exist. So its a stretch but perhaps the weird disequilibrium observed in Neptune's atmosphere could be biological in origin? Also I would worry about the weather on a global ocean devoid of any land of seafloor to slow down its currents and therefore its storms.

[@stanburton6224]

Nice thing about Enceladus and Europa both is that yes, it is a high radiation environment ON THE SURFACE, but if you drill through the ice and place a subsea habitat below the ice, the radiation is pretty much nil.

[@Keldor314]

Actually, flight trajectories involving the Lagrange points really is interesting. Orbital mechanics start doing interesting things when you're near them.

[@davidanalyst671]

yes. maybe look up a different explanation of them tho!! lolz

[@HalNordmann]

Since I wrote about the short story some time ago in the comments of one of Scott's videos, I'm glad he noticed it! Its Leonard Hansen reminds me a lot of the people mourning the "obvious loss to humanity" in not pursuing the Orion nuclear pulse drive. And yes, Syntin is a very good fuel, and can be used as a part of a mixture.

[@dustinmorrison6315]

The fuel they should use for the mission to get mankind's gut bacteria back should be Phosphorus Oxygen Oxygen Phosphorus.

[@craigduncan4826]

The phosphorus might give off a smell or something though

[@Paksusuoli95]

That molecule wouldn't be stable and therefore can't be used as fuel. Not funny.

[@bcikablam3578]

honestly this comment is genius even if it isn't possible

[@Dragrath1]

While the joke pun is all fun and games *phosphorus* is too precious to be wasted on this type of foul humor. This would be a waste of perfectly usable phosphorus the core element to life remember this is the element that scarcity (since the only environment which it is made in any appreciable amounts is oxygen core/shell burning which only occurs in the final year of a very massive stars life prior to core collapse supernovae). Then to get any real amount of this phosphorus based on what I have read you need a star that is massive enough to undergo a violent Wolf Rayet (WRO specifically) shell expulsion phase else the phosphorus produced ends up within the collapsing core rather than getting out into the surrounding universe. For this process based on the papers I read on the subject you want more angular momentum remaining at core collapse else the expelled phosphorus ends up being poorly mixed i.e. quite localized distributed only to the nearby stars in the stellar birth cluster. Notably the latter high angular momentum collapse of a Wolf Rayet class star is thought to be the conditions that produce a long duration gamma ray burst progenitor. Alternatively this is the core burning stage at which pair instability supernovae are thought to occur due to photodisintegration which notably could allow some phosphorus to escape assuming it can avoid getting photodisintegrated. Phosphorus is the most valuable element in the galaxy for phosphorus based life like us as it is the only rare element needed in more than trace amounts. ATP DNA and RNA all depend on this element which is why it is the most ecologically limiting nutrient for most life on Earth.

[@glasstuna]

Sulphur Hydrogen Iodine Tellurium. SHITe.

[@madmaxfzz]

This was a particularly good one, Scott! Love your work.

[@Hopelek]

I disagree, my lunch profiles are all about maximising deliciousness 😀

[@TomiLoveless]

Scott I am so a fan! You collaborated with my favorite author!!! Ann McCafferty is one of the best, Ann got all my attention with Dragon Riders of Pern. I even had a crush on her even though she was much older than me. I have been circling watching your vids. Scott Manley I am more than a fan now. I worked on the tooling team for the Space Shuttle, and many more at General Dynamics, San Diego. Your informed and imaginative videos are a breath of fresh air. Lots of likes and shares a comin your way Bro.

[@mckrunchytoast2469]

Time to challenge Elon to find and bring back the LM from Apollo 10 for the Smithsonian.

[@MustangBobGT]

One thing I regret at my young years was not finishing school but sir thank you in my old years it amazing to have some one like you to make me still wanna learn I know it sounds stupid but thanks

[@vmonkey1987]

Hi Scott, mam wants to know where you got those lovely shelves.

[@Zadster]

Interesting that the rad hard processors etc are made by BAE Systems (British Aerospace) in the US, and the ARM processors are of course also British in origin.

[@jfelipe1987]

Have you read andy weir's new book? Would love your review and hot takes!

[@BnORailFan]

I finished listening to the audiobook and loved it.

[@MinneapolisRaven]

I just finished the audio book too, Scott would need to plaster it with spoiler alerts, you can't talk about any of it without spoilers.

[@jackryan6446]

It was effing fantastic. I was about to say what it reminded me of, but even that would give massive spoilers

[@ericpmoss]

Something I don't understand about the cooling you mentioned at 4:00 -- I get that if one side of the spacecraft were exposed to 3K liquid helium that there would be plenty of cold atoms to absorb the craft's heat, but if the spacecraft is exposed to nearly perfect vacuum... (a) how does the heat dissipation really take place with so few atoms to absorb the heat, and (b) how efficient is it?

[@jajssblue]

Nice shirt Scott!

[@MD.ImNoScientician]

This Is The Way...

[@fabrb26]

The cat is like " Noooow ... Nooowwww... Nooowwwww " Scott " shhhhh !!! I'm filming , or i sent you to orbit in my Lego space shuttle ! "

[@Rubrickety]

Highlight: hearing the word “poop” in a Scottish accent.

[@antonystringfellow5152]

Ever wonder if Shrek was modelled on Scott?

[@5thearth]

There was a computer game called "Hardwar" (sic) set in a colony on Titan. The main gameplay was flying around in vehicles called "Moths" that had really fun flight characteristics, sort of modern drone-like. Still the best "Elite" style game I've ever played.

[@johnvalerian8440]

Would building in caves protect computers from radiation on Mars?

[@catfish552]

It should. I seem to remember proposals for Moon bases buried under a few meters of regolith for protection. I'd be surprised if no one has made similar suggestions for Mars.

[@stargazer7644]

Any long term base will likely be buried on Mars to protect the humans from solar flares and CME events.

[@JohnDoe-eo8gi]

So grateful for the free content

[@kennethng8346]

Flapping with huge wings around Titan, sounds like Wild E Coyote. :-)

[@zefallafez]

Wile

[@PiDsPagePrototypes]

1:30 "DEC Alpha" perhaps? Which was one 'the' 64 bit CPU, back when there were no other 64 bit chips. Gas Giants, just fly a really big Glider. And besides, for extra habitat space , we could always just change he orbits of rocks to build something at the Earths L3 point.

[@Caroline_Tyler]

Flapping with huge wings around Titan, Gordon's Alive!!! ROAR

[@KirstyTube]

Nice video thanks Scott. Shout out to Charles Stross, Singularly or was it Accelerando? probably some of my favourite books.

[@DeneF]

I've had a low thrust since I turned 50. Lol.

[@MusicareMusic]

you have a cat ! 8:44 Meow! that sound of cuteness overload.

[@mowgleytb]

Wait, does this mean the drone has a more capable processor than the rover?!

[@SoloRenegade]

Possibly. Past, and ongoing research, is likely to change this going forward though. top of the line COTS super computer servers have been successfully tested in outer space without the use of physical hardening techniques. New methods of radiation protection being developed.

[@afriedrich1452]

Radiation will cause a brief short circuit along a path the particle takes. One of the important things is to design the circuitry in and around the processor, etc., to limit the power through the circuit when it short circuits, to prevent circuit destruction.

[@nanotyrannus5435]

I think an interesting fuel oxidizer combination is HyImpulse who plan to use Paraffin wax and LOX in a solid-liquid combination with a few interesting properties.

[@rauladdams5709]

I love these viewer question episodes. Great stuff 👍

[@dakotahrickard]

Laughing now at the idea of basically taking paramotors (powered paragliders) into space to explore titan. But you could get away with much lighter, lower-powered frames and smaller glider wings because of the atmospheric and gravitational differences. Just kind of funny, having astronauts etc flying the most basic of powered aircraft on a moon nearly a billion miles from Earth.

[@WilhelmDrake]

@3:06 No, that's the deafening hum of the fan on my T430 Thinkpad. It's so loud you can hear in on Mars.

[@robertmiller9735]

For a base in an upper atmosphere (this goes for Venus too), I'd go with a flying wing rather than a balloon. You could even land spaceplanes on it. Jupiter is clearly out, not just because of the gravity, but the radiation. The only reason it might not be possible for the other gas giants is if their atmospheres are just too stormy. Also, I do see a way to use solar power on Titan: build a powersat, that uses enormous reflectors to concentrate sunlight on relatively small panels. Though of course nobody's going to Saturn without fusion.

[@CV_CA]

18:58 How is that work if the atmosphere is thin would not be harder to fly since you are beating less molecules?

[@rimmertf]

if only i watched this video a week ago. the lag range point was one of the hardest questions on my final exam for physics

[@istvansipos9940]

07:02 How are L1 and L2 stable? I mean, the spacecraft at L2 seems to be pulled towards the left hand side by the Sun AND by Earth, with no counter-acting force I can think of. Thanks a lot

[@AnotherPointOfView944]

I can confirm: military and space grade components are 10 years behind commercial. For testing and testing and testing. Did I mention testing?

[@SoloRenegade]

I can confirm this too. Commercial solutions are outpacing government solutions in many areas. Gov is paranoid and tests everything beyond reason. SpaceX is following the superior method of "Fail fast, fail often", for an example.

[@DrWhom]

@@SoloRenegade I don't wanna be on board a fail often kinda vehicle. also, the shit storm every time a space shuttle blew up, like it wasn't a highly advanced prototype but a yellow bus, has made gov very sensitive about manned space travel mishaps

[@SoloRenegade]

@@DrWhom Fail Fast Fail Often is a problem solving technique. You don't hve to use it, but you'll never keep up with your competitors who do use and understand it. Once the problem is solved, then you continue to use it in working out the remaining issues, until you not only have a fast-developed solution, but also a reliable one. Equating failure during development with death during operations is not what Fail Fast Fail Often means.

[@pihi42]

5 times smaller feature size = 25 times more elements per area. Now they are going into 3rd dimension, but "feature size" is still computed as "area equivalent".

[@onedeadsaint]

18:07 I see Titan come up a lot with this topic. I would like ask: isn't Europa also a great place to explore and habitate?

[@MrSlowThought]

Thanks for the Charlie Ross reference. Now I know about aneutronic fusion!