Is There a Tripropellant Rocket Engine? How Are Orbits Planned? - Deep Space Questions 21

[@TechMasterRus]

20:50 The side boosters of Energia rocket had RD-170 engines which were designed reusable and were tested more than 10 times in series without even maintennance. Those side boosters were meant to have wings and return to the runways like planes. Energia rocket could be used independently of Buran, unlike Shuttle. Only the USSR collapse stopped this program, unfortunately.

[@disketa25]

Also add that Energia series was also designed as a "golden trio" one replacing ALL the rockets with three engines and two tankage diameters: Zenit for Soyuz phaseout, Energia-M as Proton replacement and Energia itself as a (mostly) testbed for future heavy-lift reusable design, as well as launching something extremely heavy...

[@nowhereman1046]

Look up Shuttle derived vehicles sometime and in particular, Shuttle-C which would replace the orbiter with a large cargo module. The Shuttle had the potential for that, but Congress didn't want to pony up the dollars for something that would've saved billions on Space Station Freedom or eventually ISS and allowed super-heavy lift missions.

[@Boeing-I-hs2gj]

It should be known that the side booster of the orginal Energia Rocket were actually designed to have parachutes with soft landing engines and shock absorbers to land sideways in the wilderness, the Soviets would recover the boosters with two massive Mi-26 Helicopters and bring them back to Baikonur for reuse. The reason for why the first 8 boosters of the rocket were not recovered appears to be because the Soviets had yet to install the monitoring equipment required to recover them so they expended them instead.

[@michaeldunne338]

I don't believe the strap on booster were ever tested for recovery in an actual launch. I thought there was a proposal to try that after the Buran launch, but didn't come to pass. The program had issues before the USSR collapsed, having encountered significant delays and serious questions about utility; and the testing program after Buran appeared to have been placed on a very conservative cadence. For reference: "at the end of 1989 Glavkosmos chief Dunayev said that 14 billion rubles had been spent during thirteen years of development and testing." Now at that time, the space budget was 6.9 billion rubles, which at official rates at the time, equated to about $10 billion dollars. Source for those points is: Page 373 of "Energiya-Buran: The Soviet Space Shuttle" by Bart Hendrickx and Bert Vis

[@Boeing-I-hs2gj]

@@michaeldunne338 I did mention in my the comment that the Boosters on the 2 Energia flights were not recovered. I will mention that their is an old poor quality video on the Internet showing a computer simulation of how they were supposed to be recovered, although I haven't see it in a while I think it's on a Russian Space website. Thanks for the information anyway of the tragically dire financial situation the Buran-Energia program was facing by the 1990s, the Soviet Shuttle was effectively dead by 1992 although it was never officially cancelled. In my opinion the Soviet Space Program would have been much better off state if they had continued investing with the ill-fated N1 Moon Rocket beyond 1974 instead of cancelling it and wasting Billions of Rubles building a completely new Rocket from scratch with the added cost of building 5 expensive Space Shuttles, yes the Soviets were really building 5 Buran Shuttles by the time of the collapse, its no suprise that the program had cost 14 Billion Rubles by then, the development of the engines for the boosters and Energia alone were completely unaffordable for the Soviet economy.

[@rocketsocks]

The Energia/Buran architecture made it more obvious that the Shuttle is a heavy lift launcher. Every Shuttle launch delivered about 100 tonnes to LEO, it's just that 80 of them were the "dead weight" of the Orbiter itself.

[@Tracomaster]

I mean the rs-25s of the shuttle were a big part of that as opposed to the standalone system that energia was but still, lots of other mass in the shuttle

[@Zacho5]

That was always the cool part of the Energia, it could launch with a larger paload strapped to the side instead of Buran.

[@vonschlesien]

@@Zacho5 there were also plans for a cargo-only shuttle variant, but Congress never ponied up for development

[@nowhereman1046]

@@Zacho5 Look up Shuttle-C or any number of Shuttle derived vehicles where the orbiter was replaced with a side-mounted cargo module. Shuttle-C advanced to the point where the MPTA-098 was used to build a high-fidelity engineering mockup for studies on how this would work. Some of the photos of it are really impressive and show what was possible, such as a 90 ft instead of 60 ft payload bay filled to the brim with fully outfitted space station modules and other hardware to build Space Station Freedom.

[@BogeyTheBear]

Think of it as carrying your core cluster along in your cargo manipulation/return module for reuse rather than expended with the core stage.

[@BimmerDreamer325i]

11:44 Fun fact, this hotel was a filming location for the James Bond movie Quantum of Solace.

[@Transmatrix]

I thought for SURE Scott was going to mention that in his video. Was very surprised when he didn't.

[@ASpaceOstrich]

I knew I recognised it from somewhere.

[@TimPerfetto]

How dare you tell people such secrets... You need serious help and please stop ruining everyones life stupid

[@alartor]

Yep. This, along with another pretty good opportunity to reference another Bond movie with a direct connection with the topic at hand in a previous question (Diamonds are Forever)... but yep. No Sean Connery impersonation this time... 😭

[@Shmuel420]

I realized that as soon as I saw it

[@TheTonyMcD]

Lol, I love that NASA didn't feel the need to change the round holes into square holes because they now have a procedure to jerry-rig a square peg to fit it into a round hole. I mean, I understand that logistically it just didn't make sense to change one of the systems, but it is still hilarious to me.

[@axelord4ever]

There was probably logistical downstream from both the 'square peg' and the 'round hole' in this case. Changing either would have required to change much else. Cost effectiveness reared its head and they went with the economical choice.

[@benjaminhanke79]

It was a different time then. NASA accepted higher risks those days. I think that changed at least after the challenger disaster. I heard somewhere they had stored spare LHO canisters on the LEM lower stage. They would have been accessible on the EVA.

[@lyfandeth]

Timber frame buildings DO use square pegs in round holes. The pegs jam themselves in and the four sharp edges cut through the surrounding wood, locking them into place. FWIW.

[@petlahk4119]

@@axelord4ever - The other thing is that I think they made the right call in deciding that building in more redundancy to make sure they would never *have to* cram the square peg into the round hole was a better use of time, energy, money, etc. It's far, far better to never have to come that close again. And, probably the cheapest option would be to simply make a purpose-built adapter without changing out the systems built into the spacecraft, too.

[@georgejones3526]

How difficult would it have been to design an emergency adapter? It couldn’t add that much more weight.

[@JaquesBobe]

"Appretnly, there's a lot of ways you guys can send me messages!" - says flustered Scott, as owls keep circling his house, and envelopes start bursting out of the fireplace.

[@Anymal104]

Yer an astronaut Scotty! I'm a whaaat??

[@PianoMan_2112]

What house would he get sorted into?

[@PianoMan_2112]

(my guess is Ravenclaw)

[@goshisanniichi]

I saw a Buran at the Technick Museum in Speyer, Germany back in August. It was really cool. I highly recommend going. There amount of cool stuff--not just spacecraft, but also planes, trains, and automobiles, and also boats (lol)--they have there is unbelievable. If you go, make sure you get the two-day ticket and have enough time to fully use both days. It's entirely possible two days is insufficient.

[@ianchristie3995]

I saw it back in 2016 it was really cool! I also loved seeing both the concord and TU-144 in the same place and comparing their interiors.

[@realulli]

@@ianchristie3995 Concorde and TU-144 are in Sinsheim, the sister museum to Speyer.

[@realulli]

Seconded. You might want to make it 4 days and spend the other two at the sister museum in Sinsheim, about 50 km east of Speyer. Speyer has the Buran and a 747, Sinsheim has both Concorde and Tu-144. Obviously, both have quite a bit more stuff to look at. You might want to look up "Brazzeltage" (I'd translate that as "rumble days"), the next ones are May 13th and 14th, 2023. These days are basically a big party where they just show off the stuff they have. A lot of the exhibits are not just dismembered show pieces, quite a few of them (especially the cars) do work and are drivable.

[@ianchristie3995]

@@realulli yup your right went on the same day so in my memory they are in the same museum.

[@owensmith7530]

I saw the Buran in Speyer in August too! I was on a river cruise so didn't get to Sinsheim.

[@alexlandherr]

At 12:00, noteworthy for being used as a filming location in “Quantum of Solace”.

[@Joe4evr]

Was about to say "I think I saw this place in a Bond movie".

[@thesteaksaignant]

@@Joe4evr and I was about to say that ^^

[@iQKyyR3K]

My dad works with pacemakers. The plutonium ones were actually pretty good according to him and lasted for AGES. Biggest problem was you'd need to remove the pacemaker prior to the burial.

[@vikkimcdonough6153]

IIRC, a few of those are still operating _today._

[@spacecadet35]

The specific Impulse for the Liquid Lithium, Liquid Fluorine and Gaseous Hydrogen engine that was tested was 542 seconds. This compares to the highest specific impulse chemical engines ever flown, which were the Space Shuttle SSMEs with an Isp of 454 seconds. For a space craft with an alpha ratio of 0.9, this means replacing the SSMEs, it would increase the payload by 45%.

[@OpticalMan]

The US may be a scientific and engineering powerhouse but those of us in the rest of the world can only marvel at how they have ended up being unable to decide what units to use. Fahrenheit on one graph, centigrade on another, inches of mercury and millibar together on another!

[@daszieher]

"freedom units" 😂

[@TJAkin]

Maybe not a Tri-propellant, but David Woods’ fine book on Apollo describes an addition of Helium to the outer four F1 engines for pogo suppression. Those guys were pretty smart.

[@professor-josh]

Excellent book!

[@josephalexander3884]

You make complex ideas available to someone who is slow like me. Excellent video. Thank you for keeping space understandable.

[@xani666]

I remember there was a KSP mod graphing those graphs... kinda hoping KSP2 would include that in the base game

[@alexsiemers7898]

They added a stock alarm clock tool that even gives transfer window dates, and it usually matches the best times given by mods which offer a visual plot. So internally the game’s already doing it, meaning it could easily be a thing in KSP2

[@iveharzing]

I believe the mod was called MechJeb

[@johnk190]

Mech Jeb didn't show these "pork chop" graphs

[@awilliams1701]

@@johnk190 I don't know about always, but When I used it, it had them. It was under like advanced transfer or something like that. You could even tell it to include the arrival DV. Sometimes the most efficient departure wasn't a perfect match for an efficient arrival. But yeah I used it all the time.

[@Archgeek0]

@@awilliams1701 I think it was literally just called "Transfer Window Planner", and if memory serves at some point MechJeb added a hook that would launch Transfer Window Planner from one of its menus.

[@flare2000x]

There are also tri-propellant hybrids called Tribrids - some are commercially available from Rattworks - basically they are a nitrous+alcohol liquid with a polypropylene solid core - it starts as just a hybrid, then the alcohol gets added after the burn starts, and once the solid burns out it continues until the fuel runs out as a liquid biprop.

[@satoshimanabe2493]

IRL, the upper stage of the Proton may be similar to simple asparagus staging, as the Briz-M uses an auxiliary propellant tank (APT). The propellants in the APT are used first by the Briz. Once expended, the APT is jettisoned, and the Briz continues using internal tanks. (See Proton Mission Planner's Guide)

[@MikesTropicalTech]

I built my own jet shoe prototype when I was 6, using copper pipe elbows and taps that my Dad had in a box on the workbench. Never got to the point of a static fire. :^)

[@Mark_Bridges]

It's never too late, right?

[@longlakeshore]

That's probably for the best. 😎

[@mtnbikeman85]

Former nuke plant worker here. One of the other to big reasons not to use rockets to dispose of high level waste is risk. Current rockets have a failure rate of ~ 5/100 launches. Nuclear risk engineers want risks of massive releases (e.g. rocket exploding in atmosphere with high level waste) to be somewhere in the order of 1/1,000,000 to 1/10,000,000 or lower. So rockets need to get many many times more reliable before that risk is acceptable to launch spent high level waste in large quantities. Note for risk nerds, I'm ignoring conversions between occurrences per year and occurrences per event as well as a few other factors but because rockets launch so infrequently it seems negligible.

[@eckligt]

Plus it would be (and excuse the pun) a _waste_ to throw away such a Uranium- and Plutonium-rich resource as used nuclear fuel.

[@kkloikok]

More on the first question, there is a JPL tool called "SPICE" that is used to do the number crunching. its a FORTRAN program. There's also a MATLAB version (MICE), a C version (CSPICE), and an unofficial Python binding (SpacePy i think). Yes, it is free software. No, it is not easy to learn.

[@SkunkPresant]

Energia was designed to have the strap-on engines parachute back. Only the tank/booster was lost. Also it was a heavy lift vehicle all on its own. It’s first flight was with a test ‘satellite’. A remarkable vehicle but so often bundled as a shuttle launcher.

[@AlexandervanGessel]

The version I heard was that the designer knew the whole idea was stupid, so he made sure the booster could be used separately from the orbiter. Unfortunately the Soviet Union lacked the money to make use of that and collapsed before the situation changed.

[@syriuszb8611]

After Apollo 13, they have not changed the Apollo hardware, but I *think* NASA created requirement for new space ships to have all parts that can be exchangeable, be exchangeable to avoid similar issues.

[@ianchristie3995]

Your absolutely correct, I specifically remember the late 2000's NASA Constellation program mission specs require the Altair moon lander to be able to function as a lifeboat just like Apollo 13's LEM in case of a failure in the command/service module.

[@dunnwell7780]

They had actually considered this problem during the design phase, but decided that the possibility of the CM/SM being disabled, and needing the LM as lifeboat to return home was so remote, that they dismissed it out of hand. The even scarier thing is that the problem could have happened on any of the Apollo missions before Apollo 13. Apollo 8 didn't even have a LM to retreat to, or it could have happened on the return leg of 10, 11 or 12 when they had used the LM and had the same problem as 8.

[@SynchronizorVideos]

@@dunnwell7780 It wasn’t because they thought the “lifeboat” concept was too unlikely to be needed. That emergency procedure was something they prepared for. The round lunar module cartridges were also used in the PLSS life support backpacks on the lunar spacesuits. The big CM cartridges never would have worked for that. So even if they changed the lunar module to use them (taking up precious space and adding weight), they still would have had to pack along a bunch of round cartridges anyway.

[@YaofuZhou]

About the training for living on Mars thing - my physics PhD mentor decided to leave physics and become an ESA astronaut. When that did not work out, he became an climate scientist stationed in Antarctica. He has just survived another winter there, although he would not be back in civilization till early spring of 2023. So I guess Antarctica may be the next best thing if you cannot got to the Mars yet…

[@michiganengineer8621]

Or a facility like Earthship in Arizona but heavily shaded so what comes into the biosphere is roughly the same as what would be present on Mars. Heavy duty vacuum pumps to give the correct air pressure and monster air conditioning units to give the right temperatures.

[@joyl7842]

12:16 Mars does however have poor light condition for large chunks of time, when the rovers shut down until more sunlight can get to them.

[@Lew114]

The ESO hotel was in a recent Bond movie! I didn't know it was a real place. Very cool!

[@UncleManuel]

James Bond: Quantum Of Solace 😉✌️

[@mikestringfellow7999]

The idea of cargo on a cycler made me thing of an interplanetary mail hook and catcher pouch :-D

[@TechMasterRus]

8:00 It's worth processing nuclear waste and building fast neutron reactors (which Rosatom is currently doing).

[@WWeronko]

A point of interest concerning Mars Analogies, the Antarctica Concordia station comes to mind. The European Space Agency uses Concordia for fundamental research for human missions to the Moon and Mars investigating things such a coping with stress, changes in the immune system and circadian rhythms.

[@tonycosta3302]

The hotel you mention was featured in the James Bond movie Quantum of Solace.

[@Transmatrix]

I thought for SURE Scott was going to mention that in his video. Was very surprised when he didn't.

[@SynchronizorVideos]

I feel like people think the CO2 scrubber was a bigger deal than it actually was, due to the emphasis the Apollo 13 film places on it. In reality the CO2 issue wasn’t a surprise, and wasn’t really a huge concern. They knew the LM scrubbers wouldn’t keep up, and they had the adapter procedure (which had been thought of before Apollo 13 even launched) ready to go when it was needed. It wasn’t a last-minute, down-to-the-wire race against time like in the film. Compared to things like maintaining course and the unknown state of the heat shield, getting the CM cartridge to work in the LM was a pretty minor thing with no real unknowns to worry about. Also, the lunar lander’s round cartridges needed to be that size and shape because the same cartridges were also used by the PLSS backpacks on the lunar spacesuits. So even if they wanted to redesign the LM to take the oversized CM cartridges, they still would have had to pack the round ones anyway.

[@frankgulla2335]

Great Q&A and an excellent answer to the "most worthly" space project.

[@Erik_Swiger]

Since many radioactive materials stay radioactive for a long time, it makes sense to sequester them somewhere in the hope that we will develop a technology for dealing with them, perhaps even creating energy or something else, with them.

[@absalomdraconis]

Most radioactive materials that we generate are merely contaminated, and can reasonably be shoved in vaults that we could build (and have built) even today. The high-grade waste is, itself, _unnecessarily_ dangerous, as there are various things (reprocessing, and isotope breeding) that we can do to concentrate the radioactivity into "burnable" reactor fuels.

[@mikerichards6065]

The 1970s documentary series Space 1999 showed the risks of sending nuclear waste to the Moon - not least massive sideburns and a nasty outbreak of flared trousers. Awesome spaceships though.

[@professor-josh]

September 13, 1999 never forget...

[@Paulkjoss]

The two main reasons we don’t shoot nuclear waste into space: 1) Rockets have a habit of blowing up occasionally. Imagine the drama of radioactive waste exploding everywhere. 2) The pull of gravity will eventually bring that nuclear waste you flung into space right back to you like a boomerang. Kurstzgast did a great video on this.

[@eckligt]

Plus it would be (and excuse the pun) a waste to throw away such a Uranium- and Plutonium-rich resource as used nuclear fuel.

[@particle_wave7614]

Why was SLS's TWR so high compared to Saturn V? Is that just because future iterations will be heavier with the larger 2nd stage? Or is it more efficient overall? Or perhaps adding more fuel would make the TWR too low after it ditches the SRBs?

[@ryanhamstra49]

I do heating and cooling for work, we measure a few things like duct pressure and vacuum pressure in In of HG

[@HandFromCoffin]

Regarding the CO2 scrubber square peg, round hole.. I understand re-fitting and redesign was not really an option but I would have thought they'd send them up with a "pre made" bag device. It could have been folded up in an envelope and saved a ton of time making one in the middle of a disaster. That way they could sign off they "fixed" the problem. I was surprised they decided to go with the do it yourself in space approach.

[@StevePemberton2]

Would save a little time but would have also added weight and volume. Certainly only a small amount, but both weight and volume were pretty tight on Apollo so every little thing was scrutinized whether it was necessary. My guess is they preferred to just have a procedure in place for making it with existing materials already on board. And the problem doesn't need instant solving, they had many hours before it would be needed, and likely enough spare time to do it.

[@diogoduarte369]

500 seconds of specific impulse?! When do I get that on KSP?

[@MrHichammohsen1]

You are just dropping videos today! Thank you Scott, fly safe.

[@firefly4f4]

I saw the question in the title card, and I'm thinking: "Didn't Tim/Everyday Astronaut answer that question in his Soviet Engines video? Never flown, but starts off as kerosene/hydrogen/oxygen, then switches to just hydrogen/oxygen once the extra thrust isn't needed.

[@_mikolaj_]

I believe Lockheed martin wants to use NTP tug "cycling" between earth and moon in their Sustained Lunar Development program entry

[@ericlotze7724]

14:05 Previously (I don’t remember when) you mentioned some sort of *Liquid Mercury Injection System* similar to that of the Hydrogen in that Li-F-H rocket. Could you look into/cover that more in a future video?

[@Br3ttM]

I think that was where he talked about the book *Ignition!* I don't think the book said that much about it, due to it being some military program, and most of what was said was just how bad of an idea it was.

[@cyberenby3015]

On the topic of Asparagus staging the best way to do it that I know of was on the proposed UR-700. Its boosters would have a sort of 'integral drop tank', which was a second set of propellant tanks mounted on top of the first, and they would feed into the core propellant tanks - but crucially NOT into the core propulsion system. The idea being that by topping the core off mid flight, they would avoid the issues previous attempts at cross feeding experienced.

[@jonslg240]

Brad Allen is honestly a genius amongst your question-askers. His question is the best I've seen you air in at least 26 weeks.

[@thomashiggins9320]

Hopefully, the Mars homesteading project would turn out much better than the Biosphere 2 test, did.... 😖

[@ericlotze7724]

TFW You forget concrete cures, focus on fancy plants rather than life support, and don’t screen+prepare your crew emotionally

[@absalomdraconis]

@@ericlotze7724 : Also a lot of desert simulation, which adds nothing to life support at all.

[@josephalexander3884]

As an aviation aficionado. You are a nerd for me to understand everything. Thank you.

[@yes_head]

I love Scott's channel. Who knew "pork chop plots" and "asparagus staging" were things? 😄

[@Krzysztof_z_Bagien]

pretty much everyone who plays KSP :D

[@asparagusstaging430]

I did.

[@ioresult]

I can spend litterally hours in Kerbal plotting gravity assists. I'm always wondering if there are better ways. KSP's Transfer Window Planner mod is barely a starting step. Try next orbit, adjust time, next orbit, adjust time, too far, go back 3 orbits, no was going in the right direction, go forward 5 orbits, oh no forgot a detail, start over, rince repeat.

[@CessnaPilot99]

For some people that sounds like torture but I can totally understand getting into a game regardless of what it is and trying to perfect it. You sir are a true gamer

[@lewismassie]

Fun fact about the Buran, they calculated the launch rate the Shuttle would need to be worthwhile, saw that NASA couldn't do that, and then concluded that it must be a military platform. Energiya-Buran was taking about half of the entire budget when it was cancelled

[@professor-josh]

Yes, I've heard that too, possibly in a Scott Manley video. Big spaceplanes ate the budgets of at least three or four space programs: US, USSR, France/ESA (Hermes) and UK (HOTOL).

[@Infinite_Maelstrom]

Also Sänger (DLR)

[@deusexaethera]

6:46 - "Also, Falcon Heavy has a pretty small fairing, so even if you could put huge amounts of mass on top if it, it would have to be very compact and hard to do." Thanks, Scott, for destroying my dream of launching a 10-foot tungsten cube into low Earth orbit.

[@laurentch.3831]

The asparagus-staging question might have been referring to the UR-700/UR-900 soviet designs? Those certainly look very Kerbal-y, like an actual bundle of asparaguses in fact. :D

[@u1zha]

Yes, the moniker isn't new. See Scott's earlier videos about OTRAG

[@laurentch.3831]

​@@u1zha Right, thanks for reminding me about that one! A bit different than what Scott defines here as asparagus staging though, since each "asparagus" is independent, and the stages are lighting and separating in sequence.

[@u1zha]

@@laurentch.3831 True, that's an important point.

[@vikkimcdonough6153]

6:10 - IIRC, there were also studies done at some point about using fuel crossfeeding (onion/asparagus staging) with the Delta IV Heavy (mostly in relation to 4-and-6-booster expansions thereof).

[@jlp1528]

Good information as always, keep doing these! Also, Kurzgesagt recently released a very good video explaining why shooting nuclear waste into space is a really, REALLY bad idea. Elina Charatsidou promptly made a reaction video in which she corrected a few minor things but mostly just confirmed and elaborated with a couple laughs thrown in. Great stuff!

[@zoperxplex]

What torpedoed the Buran space shuttle was not it's questionable practicality as a space launch system but, rather, the demise of the Soviet Union and the fact that Russia as the successor to the U.S.S.R. space program lacked the financial resources to continue with the project.

[@MrGrace]

The jet shoes sound like a hilariously bad idea 😂

[@jpdemer5]

After Apollo 13: "Let's put an extra roll of duct tape in the toolkit."

[@jessepollard7132]

Of course - the closest simulation of Mars is the Atacama desert. no water, perchlorates in the soil, low pressure (not as low as Mars of course). The problem is building the habitat there. From what I've read, there is a small village at the south end where there is a bit more water.

[@MCsCreations]

You know, Scott, the Buran history gave me an idea... I always wanted to build a model rocket, but at the same time I've always found the idea pointless... Because I would launch it once and never again. BUT... If I build a small rc glider to be launched on top of it... Made of foam, it would only need a few servo motors and FPV gear, so the battery could be small... It could be a lot of fun! 😃 Specially if I launch it from somewhere with lots of termas, like from where people go paragliding! Anyway, stay safe there with your family! 🖖😊

[@yahccs1]

Great questions and answers! Thanks for mentioning mercury inches. My Mum's had a barometer in the hall that is probably at least 70 years old if not 80 or more and still works fine, so I got used to seeing the pressure between 28 and 30. I think the lowest I ever saw it was just above or below 28 and the highest just over 30.1 It's usually between 28.5 and 29.5 (I don't know what altitude it was calibrated for - it might have that written on it). I don't think we learnt about pressure in mercury inches at school or uni - only millibars or Pascal, which are easier to do maths with! It would have been nice to know the connection with mercury inches (or cm) and Pascal, and how the old barometers worked.

[@CharlesStearman]

Mercury barometers essentially use the weight of a column of mercury (with a vacuum above it) to balance the weight of the atmosphere - the height of the column varies with air pressure and it is this height that gives the 'inches of mercury' reading. It does not have to be calibrated for altitude, though obviously the reading will be lower at higher altitude. An altimeter, on the other hand, converts air pressure into height, and therefore does require adjustment in order to read zero when the aircraft is on the ground (it can also be set to show height above sea level, which is what pilots generally mean by 'altitude'). For commercial flights it is usually set to read zero at the 'standard' sea-level pressure of 1013.2 millibars or 29.92 inches of mercury (which is the theoretical sea-level pressure of the atmosphere when undisturbed by weather patterns) - this ensures that two aircraft whose altimeter read the same will actually be at the same level irrespective of what the actual sea-level air pressure might be. The term 'flight' level' used by air traffic control refers to the height in 100s of feet indicated by an altimeter set in this way (so if it reads 33,000 feet the aircraft's flight level is 'three-three-zero').

[@yahccs1]

@@CharlesStearman Fascinating, thanks.

[@StevePemberton2]

@@CharlesStearman 29.92 is only used above 18,000 feet, which is the first flight level. Actual reported barometric pressure is used below 18,000 ft. At high altitude you want to know your vertical separation with other aircraft. At lower altitudes you want to know your height above terrain and height above the airport.

[@Arachnos27]

CodysLab has a pretty nifty mars habitat simulation series, it’s not as extreme as the conditions you were saying would be ideal but still awesome to watch. He’s doing it all solo and has some cool ideas. It’s called the chicken hole base

[@GaiusCaligula234]

It's really boring and goofy

[@Arachnos27]

@@GaiusCaligula234 to each their own, he’s doing it all solo and I find it interesting

[@HL65536]

For asparagus staging, instead of feeding the engine from 2 different sources, they could instead put batteries in the booster nosecone and drive electric pumps that feed directly tank to tank. Then just use the same plumbing you use on the pad to fuel up. The center core then has to have 2 such inputs (1 on each side), while the boosters have 1 input and 1 output. The pad would then fuel the boosters which then use their pumps to fuel up the center core. In flight, these pumps continue to run (they just switch to batteries) and cross-feed until separation. And it wouldn't have to run the outer tanks 100% dry, there should be enough performance gain if the pumps would run until 10% fuel left, so they can be placed just anywhere on the bottom of the tank. And for everybody that thinks electric fuel pumps are not possible for larger rockets: it's a lot less problematic than replacing turbopumps with electric, as the pressure requirement (and therefore the power needed) is much lower for tank to tank transfer.

[@somerandomnification]

Doesn't it take longer to fuel a rocket then to empty one in flight? It seems like electric pumps would have to be huge (and heavy) to match the fuel burn rate.

[@HL65536]

@@somerandomnification 1: yes, but nothing speaks against just having some headroom in what the pumps can handle and running them slower on the pad. 2: The Rutherford engine has electric fuel pumps and still has a TWR of 72, which is not that bad. And there the pump has to generate a lot higher pressure, which is not the case in my idea. And weight does matter a lot less in the outer boosters compared to later stages, and even more so if they are non-reusable (where my idea would work best).

[@SynchronizorVideos]

The turbopumps on large rocket engines are monsters. Hundreds of pounds per second. Having plumbing, pumps, and power supplies that could transfer fuel & oxidizer fast enough to keep up would add a lot of weight. A more efficient approach would be to have valves and plumbing so that the turbopump itself can pull from & switch between multiple sources, but even that has some major challenges.

[@maurobagnoli3415]

seems easier to feed the central engines from the side boosters and when they are depleted start using the central core fuel than switching fuel from one booster to the other

[@SeanBZA]

Easier to just shove engines on, and drop them and the pumps when empty. They only have to be carried for 3 minutes then, otherwise you still have to carry probably 2 tons of plumbing and valving to orbit. Soviets ISTR did make drop off tanks, but gave up and slapped on simpler cheaper solid cores instead, easier to design and control. Extra tanks add weight that you have to take to MECO. Easier to dump parts after empty, and only take 100kg of attachments and stiffener ring you already mostly need instead.

[@Erik_Swiger]

Around 13:55 Damn. A chemical reaction that can interfere with radio signals. Damn.

[@SeanBZA]

Well Apollo showed that with the lightning strike that dropped the CM offline, while the instrument ring on the third stage was supremely unconcerned. Switch SCE to Aux, to reset the power supply that tripped out from the transient. Hot enough from LOX kerosene to ionise air, just this is a whole magnitude worse, as you now have metal ions in the exhaust as well, not just carbon ions.

[@absalomdraconis]

Makes me wonder if you could use the exhaust as part of the antenna.

[@D_Rogers]

The advantage of a Cycler is extra room and enough mass to incorporate GCR protection... But I wonder if the longer journey time, resulting in greater GCR exposure, is worth it? Which is better? A shorter journey with less radiation protection, or a longer journey with more GCR protection?? :)

[@absalomdraconis]

The real secret with a cycler is that there's no real reason to _stop_ building one. Combine that with in-space construction and recycling, and they eventually iterate all the way up to fully shielded O'Neill colonies.

[@CyFr]

Pork chop plots certainly sounds better than stomach plots

[@un2mensch]

It should be pointed out that most nuclear waste is actually not waste at all, but unspent fuel "contaminated" with radionuclides that don't play well with legacy reactor designs. However, there are many other kinds of reactor (eg, fast & thermal breeder reactors) that have much better fuel economy, some of which will happily consume nuclear "waste" after a bit of processing. So no matter how you look at it, launching nuclear waste into space is a totally counterproductive idea.

[@TheEvilmooseofdoom]

And I was taught most nuclear waste is low level stuff, byproducts etc.

[@eckligt]

@@TheEvilmooseofdoom I think he means the larger part of what is inside "high-level waste" is not actual waste, but a wonderful resource.

[@matthewcox7985]

Re: Homesteading Mars - How's Cody's Lab doing with the Chicken Hole Base project?

[@mc-zy7ju]

? No, I don't remember nuclear pacemakers. Im definitely going to look now. Btw jet shoes sound amazing, just needs a flight controller.

[@TheZoltan-42]

They had one. It was called an astronaut :D

[@Michaelonyoutub]

15:30 In Legend of the Galactic Heroes they have space fortresses the size of planets/moons that have surfaces of mercury, which is truly an ingenious concept. If you fire a laser at the surface, the reflectiveness of the mercury would reflect it away. If you bombarded the surface, it would only temporarily displace the mercury before it settles back to a smooth even surface. The fortress even had turrets which could sink, float, and move about the surface, allowing them to hide away and secretly rearrange themselves or potentially be repaired safely internally. The hangar entrance for ships also is retractable to bellow the surface, protecting it and preventing entry. It is the best sci-fi concept for a planet sized fortress I have ever seen.

[@testchannelpleaseignore2452]

7:40 there are Boeing documents that discuss a Delta IV Heavy with propellant crossfeed, 6 SRB's, and densified propellant that can apparently do 50+ Mt to LEO or 20 Mt to c3

[@filonin2]

"Mt" = megaton. I don't think it can lift 10^9 kilograms.

[@SynchronizorVideos]

@@filonin2 I think they meant metric tons.

[@testchannelpleaseignore2452]

@@SynchronizorVideos yes. That's how it was written on the Boeing slide deck I was reading from. Sorry for any confusion.

[@Retired-Don]

Opinion:. The confusion started when the metric guys took the English/American ton (2000 pounds) and decided to make up the metric ton (tonne?) and instantly cause confusion with the "other" ton. Why not simply use mega gram? 20 metric tonnes is 20 Mg. I mean, meter isn't called a yarde, even though they're "close," is it? Don't get me wrong. Metric is good. But "metric ton" isn't. :-) but I suppose "metric ton" is here to stay.

[@benjaminhanke79]

08:29 "Nuclear diamond batteries" Dave Jones from eevblog took a look at this about a year ago and was not convinced.

[@SeanBZA]

Well yes, the currents involved are minuscule, and the price really puts them in the "we got a budget that is not a worry, and we do not want a battery that will leak ever" camp, and the main use is as memory back up, as it really can only supply 100nA of current, so most uses are as standby power source for memory back up, where you need to first make sure your memory uses less power. Consider these batteries in the forms normally seen, DIP24 ceramic package, can be shorted out merely by a fingerprint on the board allowing enough current to flow, and you typically also use ultra low leakage capacitors (PTFE dielectric, none of that rubbish ceramic, electrolytic or tantalum capacitor will do) to store charge to allow them to deliver a current pulse for other applications. Yes you can make a clock that will run forever off them, though you will find it hard to find a foundry to make the large dimension IC to get low leakage, and a display will similarly have to be specially made, probably both will be a SOS (silicon on sapphire) structure, with the LCD laser sealed after filling with the fluid, to keep it from degrading. Might be done for a $500k watch, because for sure the mech will cost more than making the case out of platinum iridium alloy.

[@iancooper8777]

A quick calculation based on the beta decay of Carbon 14 to Nitrogen suggests that 1 gram would give a current of ~8nA and although the electrons would have an average energy of ~50KeV there's no super-efficient DC to DC converter which could exploit that potential to make an efficient "nuclear battery". Even if it could be made efficient that would still only be 0.4 milliwatts of power (50000x0.000000008), about enough to illuminate a very small LED!

[@ericlotze7724]

@@SeanBZA Damn, you seem to know your Semiconductor Stuff! Do you know much about VFDs? Also just making videos may be a good idea if you have the time

[@SeanBZA]

@@iancooper8777 Yes they dump most of the electron energy by using a high bandgap semiconductor to capture those electrons. Think large area Silicon carbide LED's used as electron capture devices, dumping the rest as heat. You stack the thin film detectors on either side of the source, to capture the most energy, and pump the assembly down to a pretty good vacuum as well.

[@SeanBZA]

@@ericlotze7724 Not much about VFD's other than they all die eventually. The SOS construction because you have to grow a film on an insulator for electrodes, and sapphire in pure form is transparent, and making the whole clock in the display area is possible, as the electronics can all be coated with silicon nitride to provide isolation afterwards, except for some bumps at the edge of the device that are built up with aluminium to make the top layer connections. You probably will want to use an electrochromic display instead of LCD though, as that saves a lot of power, though you will still need to have a capacitor to store the energy needed to refresh the display, which likely will only update once a minute. But same construction physically as LCD, just needs a very low current high voltage (around12V) power source to do the update. Going to be fun to do the crystal drive though, with nanowatts of power available, and typical watch crystals being in the microwatt range for drive. Battery array likely to be a lot bigger and thicker than the display. your wristwatch is going to be Rolex Oyster size, and only rated to 10m depth.

[@GNP3WP3W]

Fun fact about nuclear waste, the EU actually recycles their nuclear waste (some of which can contain a large amount of reusable fuel), whereas the US has a law forbidding the recycling of nuclear waste which requires it to be stored. Lobbying at it best….

[@owensmith7530]

Do the Viking engines on Ariane 1 to 4 count as tri propellant? As well as dinitrogen tetroxide and UDMH (or UDMH/hydrazine mix) they had water injection. It was for cooling but there are three different tanks having their contents injected into the engine.

[@alexlandherr]

So that Lithium-Fluorine-Hydrogen concept could be used for an “un-jammable” missile?

[@TlalocTemporal]

I think it would be self-jamming, and you would need to make it work regardless of interference just to fly by itself!

[@alexlandherr]

@@TlalocTemporalGood point! Still fun though.

[@MaryAnnNytowl]

I really love these, Scott! Thanks for all you do! ❤️❤️

[@hermannabt8361]

You’re right, Buran made no sense. Energia however is still missed.

[@NoNameAtAll2]

name for asparagous staging comes from some random video from early ksp (2011-2012) that compared several fuel line schemes asparagous gave most dV, but less trust (you lose outer engines faster) sadly I think that video is gone now

[@nicewhenearnedrudemostlyel489]

"some random video" This means something different to you than me. Lol. Cupcake ksp is random. You know?

[@NoNameAtAll2]

@@nicewhenearnedrudemostlyel489 a) I don't remember him b) the channel with that name has first video from 2013 at ksp 0.18 - which is too late do you have a link to what you remember?

[@1kreature]

"of you answer questions there I will eventually get around to answering it..." Nice :)

[@Life_42]

I love your room/office!

[@rodsprague369]

I think a good plot device for use in stories would be one or more cyclers that grow to be space colonies in their own right.

[@IanGarris]

I always thought about the potential for using liquid CO2 as reaction mass to lower the throat temperature, basically trading temperature for kinetic energy. Liquid CO2 is nice and dense and easily able to self-pressurize, minimizing the mass penalty for a third propellant tank and resulting turbopumps.

[@jimmymcgoochie5363]

You might get more thrust, but ISP would tank since much of a kerolox rocket’s exhaust is steam (H2O) rather than CO2. Lighter molecular mass = higher exhaust velocity = higher ISP.

[@andreask.2675]

I don't remember where but I could have sworn somebody saying/writing that the Falcon Heavy uses that kind of fuel transfer to the center stage...

[@JohnR31415]

Early plans - too complicated in real life.

[@AlexandervanGessel]

Modifying the core for attachment of the side boosters was way more work than they expected, and engine improvements basically ate up both the need for the extra performance, and the market for the Falcon Heavy (by expanding what the Falcon 9 could do). It might still have been worth the development cost if they were expecting to fly dozens of them, but at that point, the expectation was "maybe we'll fly 10 of them before it gets obsoleted by starship".

[@adsilcott]

Great answers to great questions!

[@benjaminshropshire2900]

Another "tri-propellant" concept is basically doping the fuels for different reasons. IIRC there are solid rockets that asymmetrically inject stuff into a fixed nozzle to generate asymmetric thrust for guidance. Another case is where the simple reaction isn't usable for some reason; the V-2 used a LOX-ethanol-water system to keep the temperatures down (that said, the ethanol and water were pre-mixed). One of the crazy things dried (on a test stand) was to inject a third component to increase the density of the exhaust (giving higher volumetric specific impulse); the case I'm remembering involved a manager not getting that a comment was a joke and resulted in a rocket who's exhaust had significant amounts of *mercury* in it being test fired.

[@jeffhurckes190]

IRL asparagus staging just has too many unknowns and points of failure that could result in LOV/ LOCV. The diverter valves needed to switch from one fuel/oxidizer source to another could fail in transition, and at tank separation, that is now a massive leak path. You also run into the possibility of being a restriction during the switch, which could cause the fuel or oxidizer to cavitate in the turbopump, which would be catastrophic.

[@SimonAmazingClarke]

Asparagus fuelling. The biggest problem is temperature of liquified gasses. If the LH2 or LO2 is a few degrees different to the tank it is going into, it can end up burning off more than it is adding.

[@filonin2]

How would a temperature difference lead to anything burning off? If they both remain a liquid it won't matter.

[@absalomdraconis]

The secret to solving thermal differences, as always, is to keep the propellants mixing between different tanks. Though I would suggest using one of those "banana skin" wrappers to provide extra pre-launch insulation...

[@TSBoncompte]

you know who would be able to do asparagus? those guys with the electric pumps.

[@jamesmnguyen]

Having Lithium and Fluorine in a potentially exploding rocket seems pretty dangerous to me. Maybe more dangerous than Hydrazine, but I'm not sure.

[@richb313]

Thanks Scott

[@anthonykevinkerr3594]

Tri-propellant rockets. The most recent one of these was Blue Origin's BE3 with an engine rich exhaust. Wasn't planned and didn't run well so it aborted.

[@realulli]

The full size Buran never flew in Space (AFAIK). Unlike the Americans, the Russians didn't launch Buran from the An-225 for the flight tests. They put a set of normal jet engines on it and just launched from the ground. There was a scaled down test article they did fly and use for reentry testing. Both the Buran with the jet engines as well as the scale model are now in the Technik Museum in Speyer, Germany. You can look at the test model really closely (I don't remember if you could touch it, it's been a few years) and you can climb into the real Buran. REALLY worth a visit.

[@TheEvilmooseofdoom]

Yes, Buran completed 1 test flight.

[@enisra_bowman]

Kurzgesagt made a Video and analysis about the whole radioactive Spacedumb and well, sufficient to say: you might need the Eagles from Space 1999 to make this near practical P.S. i wonder if they would still use the exploding Dumb the Gimmik that kicks of the Series if they would make a Remake of that show

[@michiganengineer8621]

Please DON'T give them any ideas! With very few exceptions, anything Hollywierd remakes is much WORSE than the original. As bad as Space:1999 was (cheesy FX/storyline/science, well it WAS a Gerry Anderson production after all), the thought of how horribly it would be remade should be enough to give anyone who enjoyed the original nightmares 😄😂

[@enisra_bowman]

@@michiganengineer8621 BSG? Thunderbirds are GO?

[@michiganengineer8621]

@@enisra_bowman I said it was cheesy, not that I don't enjoy watching them 😄 I _LOVE_ the old Gerry Anderson shows with their "Super Marionnation" TBH, the only show I can think of (that I've seen at least) that is cheesier than Star Trek:TOS is Dr. Who

[@filonin2]

I've read your comment 5x and I can't makes heads or tails of it. Total gibberish.

[@robertarmstrong3478]

The rationale for a cargo cycler would not be to save delta V but to utilise existing capacity to transfer to and from the cycler. Of course, as 'cargo doesn't care how tightly its packed' it can travel in a can on the outside of the cycler. Presumably, once you rendezvous with the cycler, the mass to be cycled is almost* irrelevant, as long as your transfer ships can handle it at each end. You then don't need to send a separate set of engines, control equipment etc along just with cargo when you already have all that on the cycler. *The cycler might need somewhat beefed up systems to handle an on cycle correction if that was envisaged.

[@impasta6315]

A interesting video idea would be the failed Hotol program

[@44R0Ndin]

I wonder if you might consider doing a video on the various ways of getting to orbit from the surface of an Earth-like planet (or the Moon, or Mars) that specifically DON'T need rocket engines to get off the ground. Spin Launch is the most recent serious study into the matter, but I'm not talking about JUST that, and that's also already been adequately covered by your existing videos. I'm talking about things like Lunar mass drivers for sending ISRU produced water, rocket propellants, and maybe even metals to orbit, Lofstrom Loops to get on a low eccentricity suborbital trajectory from the surface of the Earth, Space Elevators (as impractical and nearly impossible as they are for Earth, they'd probably make a lot of sense on Mars and Mars already has 2 very handily placed "counterweights" already in orbit that just need a little bit of orbit modification, in the form of Phobos and Deimos), and even things like Scram cannons, ram accelerators, and Rotovators. Scram cannons (and their lower-tech bretheren, Ram Accelerators) especially are an incredibly interesting thing to look at. They're basically the bastard child of a Scramjet (or ramjet) and a Combustion Light Gas Gun, if you look at it from the right angle and squint a bit. Like a combustion light gas gun, they burn a gaseous fuel oxidizer mixture to propel a projectile at incredibly high velocities. However, like a scramjet or ramjet, they do not combust all the propellant all at once. I'll be describing the scram cannon preferentially, but a ram accelerator can use mostly the same configuration of elements as long as the flow thru the ramjet drops below the speed of sound at some point. To my knowledge, that is the only major difference between a Scram Cannon and a Ram Accelerator. A scram cannon's projectile seats against the barrel in a way that there is a radially symmetrical, very specifically shaped passage created between the inner wall of the barrel and the outer wall of the projectile. This passage is shaped to create the correct geometry for a scramjet (or in the case of a ram accelerator, a ramjet). Before firing, the entire length of the barrel ahead of the projectile is filled with a fuel-oxidizer mixture suitable for use by the scramjet, there may be easily perforated barriers placed along the length of the barrel in order to allow the fuel mixture to be varied along the length to better optimize the fuel mixture for the increasing speed of the projectile and therefore higher mach numbers that the scramjet projectile must operate at. At the breech end of the scram cannon, there will likely be a taper similar to the forcing cone that transitions from the chamber of a more traditional rifle to the profile of the rifled barrel, however in this case it is only needed because the projectile must be introduced to the barrel at significant velocity and it eliminates the need for overly tight tolerances between the projectile feed mechanism and the barrel itself. In any case, to fire a scam cannon, the barrel is filled with the appropriate fuel-air mixture (as noted, with a sufficiently long scram cannon the barrel may need to be separated into sections with differing fuel oxidizer ratios to account for different operating conditions), and the projectile is forced into the breech end of the scram cannon at a speed that allows the projectile's scramjet to start creating useful amounts of thrust (so it would likely be a combustion light gas gun if only because that's the tech that's best known and easiest to implement). Even with a short scram cannon that doesn't need to adjust the mixture of fuel along the length, the breech and muzzle of the scram cannon must be sealed to prevent the fuel oxidizer mixture from escaping. When the projectile is introduced into the breech end of the scram cannon, the scamjet is ignited by some means (easiest would likely be either a TEATEB injection into the combustion chamber of the scram cannon projectile, a pyrotechnic ignition system, or an electrical spark supplied by an arrangement of electrodes in the barrel of the scram cannon near the breech). When ignited, the scramjet projectile is then free to accelerate the full length of the scram cannon's barrel, burning the fuel mixture along the way to accelerate smoothly up to an incredibly high speed (mach 10 should not be too difficult to achieve with a sufficiently long barrel and well optimized fuel oxidizer mixture selection). If the barrel is segmented, there is also the option of changing not just the fuel mixture ratio, but also the fuel and/or oxidizer themselves. So you could for instance start off with the scramjet burning a methane-oxygen mixture at lower velocities, and transition to a hydrogen-oxygen mixture as the velocity increases to the point that the chemistry of the methane-oxygen mixture becomes a limiting factor to the continued acceleration of the scramjet projectile. Additionally, because the barrel is sealed, you don't have to use atmospheric air, or even atmospheric pressure. You can use higher pressure, or lower pressure, and mixtures with a higher amount of oxygen in them. With appropriate design of the scramjet projectile, this should allow for the length of the scram cannon to be significantly reduced (if using atmospheric air, it might take 100km of cannon barrel to reach mach 10, but with higher pressure mixtures that are composed of only fuel and air (and maybe some helium or hydrogen as buffer gas if the reaction would otherwise be too hot for the scramjet projectile to handle), that length should be able to be reduced to maybe 10km or less (likely less, my thinking is that 5km would be plenty long enough if it was tuned just right). When you start talking about reaching mach 10 within 5-10km of a standing start, you start thinking that you can get to orbit without much extra effort, if you can just avoid slowing down in the thick lower atmosphere. The main reason that scram cannons and ram accelerators have not been developed is that they take up a lot of room, serve pretty much only one purpose (space access), are virtually impossible to weaponize (because you'd have to STEER something going that fast), and the need for lots of payload launched to low earth orbit when that payload is comprised mostly of commodities like water or metal ingots or other cargos that are entirely insensitive to high g forces basically doesn't exist right now. Same kind of problem the Lofstrom Loop has, despite that being one of the CHEAPEST ways to get things into space (all it takes is a couple gigawatts of power from something like a nuclear power plant and it will fling something like 10k tons to orbit over the course of a year's work, even if it only launches something maybe 2-4 times a day and spends the rest of the time speeding the loop back up for the next launch).

[@viccie211]

That hotel from 11:49, is that where the end of 007 Quantum of Solace was filmed?

[@lewismassie]

The issues with asparagus staging are made worse by the extra complexity you'd add. Adding the fuel lines in KSP adds pretty much nothing to the overall craft. Also add in the fact that often the booster sections aren't where most of the orbital velocity even comes from

[@Archgeek0]

Also the *pumps* . KSP-style asparagus would often have _chains_ of 3+ side boosters feeding into the core, which means that while the fuel flow for inner pumps would be some fraction of the core's consumption, the next pump out would need to move that much fuel plus the consumption of its own engine(s), and the next pump all of that fuel, as the outer tanks are feeding literally every engine down the chain to the core. The numbers work out to frightening fluid velocities (assuming the wee fuel lines seen in game), which would definitely cause a rotational moment in a lot of setups, not to mention a frightful amount of sloshing.

[@joshuacheung6518]

Well, you don't need to feed enough to keep the innermost tanks 100% full at 100% burn to see a benefit. Whether or not the benefit is worth it is up in the air (or not) but i think there could be a significant benefit if it could be done reliably and without too much additional weight

[@kbahrt]

Thinking on space occupation, do you think it would be possible/viable to use the fuel tanks themselves as habitable space? IE: you send up three rockets, one acts as a center point/docking station (similar to what you had Stowaway), then have the other two attached to it by cables, fire the last of the fuel, and then use the empty tanks as habitable space?

[@TheEvilmooseofdoom]

It would depend on what was in the tank. LOX tanks, no issue. RP1 tanks would take some.. cleaning.

[@ericlotze7724]

I think “wet lab” was the term for using tanks as habitats, although i know *nothing* about the prep work needed for that / rocket plumbing!

[@absalomdraconis]

@@ericlotze7724 :Wet hab, so literally only 1 letter off, though if you put a lab in one it would obviously be a wet lab as well. The defining prep work is to do something to get rid of any undesired remaining propellant, and removing any components that are needed for the tanks but in the way for a habitat. All other prep work would be standard space station setup work, albeit perhaps involving more equipment installation than normal (since you might not want any equipment to be exposed to your propellants...).

[@Michaelonyoutub]

You would have to completely tear parts off the tank for holes to allow access since tanks generally aren't built with holes big enough for people to fit through. Then you also need to reseal those holes with doors/hatches or even potentially walls. The interior also doesn't have electrical/data hookups so you will have to wire that, and there isn't any ventilation/life support functions which likely is necessary. While it is all feasible, it requires a lot materials and techniques like welding and metal work, potentially to high levels of precision, which we just have not fully develop/tested yet in a 0g environment. For the mean time, sending stuff up fully assembled from the beginning is a lot more preferable than a whole bunch of materials which will weigh nearly as much and which will be reliant on manufacturing technics which are likely poor, untested, and unreliable. In the future though, especially when materials for spacecraft start getting sourced from places in space like asteroids, manufacturing technics will advance and recycling tanks like that will likely become common.

[@ericlotze7724]

@@Michaelonyoutub But Skylab was so R o o m y

[@porscheguy5848]

Please do a video on underground nuclear testing!!

[@ericlotze7724]

I always wondered if planning (to be the right depth + rock etc) + standard “fugitive dust emissions” control practices (wet down, “rhino snot” sprays that make the dirt into a geopolymer, etc) or even a Containment Building OVER the Borehole could allow for Fallout Free Nuclear Testing.

[@ericlotze7724]

Also Pure Fusion (Maybe even particle accelerator Driven (due to mass/bulkiness being a non-issue) ) Nuclear Explosives for Project Plowshare type Peaceful Nuclear Explosions, and how much fallout those would cause/similar ways to abate that as I mentioned above.

[@dantreadwell7421]

Ooh, a 'Fly Safe, or else' ending. Nice

[@FortyBot]

most solid rocket motors are tri-(or more)-propellants: fuel+oxidizer+binding agent

[@sirjohniv]

I cant wait until we as a society figure out Avocado staging

[@senioravocado1864]

Avocado staging? Am I missing something?

[@sebdapleb1523]

add lime and salt. Guacamole staging.

[@LazySpaceRaptor]

How do you mean? Like a fairing that's also part of the booster stage separates to reveal a smaller stage within, and carries another stage inside and so-on?

[@alfonsopayra]

?

[@gochanny]

would Neutron count ? 😂