How Will SpaceX Starship Overcome This Crucial Problem?

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SpaceX’s Starship is an engineering marvel knocking off one challenge at a time before we can see them design solutions to the future challenges. Here is the question. With the LOX and CH4 storage and temperature challenges, how can they store them together for long periods of time. Indeed, How Will SpaceX Starship Overcome This Problem? Secondly, how with they solve Zero Boiloff (or near zero boiloff). For the past few months now we’ve been working on this deep dive which started off as one thing, and then morphed into another. Mainly due to it sending us down a few rabbit holes. Because we are on a short break, we’ve worked twice as hard to make sure this one was finally ready to go, and I think you are going to find this one really interesting.
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[@brandyballoon]

<a href="#" class="seekto" data-time="454">7:34</a> I'm trying to wrap my brain cells around 5 tons per second fuel flow 🤯

[@JeromyBranch]

Lol exactly my thoughts! I used to haul fuel. A large pony motor will pump at around 800 gallons per minute. Some of ours were 400. But then, we didn't have 5+ Gs helping out!

[@professor-viewsalot]

Imagine going into a petrol station with Starship and saying 'fill it up' the bank of England can't print money that fast, THANKFULLY, the corrupt uk governments don't often spend it that fast either.

[@tactileslut]

It's hard enough dealing with quoted flows over and through dams after storms, and that's when we can see it going.

[@iamaduckquack]

@@professor-viewsalot Way to shoehorn politics into a completely unrelated topic and country.

[@oldschoolman1444]

​@@iamaduckquackI think the professor has a good view of his backside.

[@holographicman]

4 minutes in the video and it blows my mind imagining all the steps, the years of years and people working on problems and patents and.. It just goes on. Thanks for the video Marcus

[@rogerforsman5064]

And yet they learn nothing at SpaceX!

[@holographicman]

​@@rogerforsman5064Hi :) and that means? I can't read your mind

[@ToIsleOfView]

@@holographicman The pipe inside the tank is amazingly complex. All of it must be precisely welded. There is no room for error, and live testing is the best way to check for the correct design. It blows my mind when I think of all the failed attempts to land and how each one led to new improvements. Software and hardware must be upgraded every flight to get it more reliable. SpaceX rocket engineers are the best in the world.

[@GntlTch]

@@rogerforsman5064 And this is the poster child of the pot TRYING to call the kettle black!

[@rogerforsman5064]

@@ToIsleOfView And still they did not count for momentum of the liquid fuel that ruptured the tank!

[@MikesTropicalTech]

Thanks for this deep dive. I didn't understand how those sub-chillers work, but it makes so much sense now.

[@yumazster]

They are routing propellants through liquid nitrogen using small ppipes submerged in the liquid nitrogen tank, which is colder and so the propellants temperature drops as it exits and is then loaded into the vehicle. Heat absorbed from the propellants causes a portion of liquid nitrogen to turn back into gas form which is then vented, carrying the heat away from the subchiller. I hope this helps.

[@ShssaelPerez]

@@yumazsterI had the same question. Thank you for the succinct explanation.

[@MarcusHouse]

@@MikesTropicalTech Glad it helped. Thanks to @yumazster for the added context.

[@yumazster]

@@MarcusHouse You are welcome 😁

[@r0cketplumber]

In 2005 I built a liquefier for natural gas using LN2 and the municipal natural gas in our hangar, but it was a terrible idea- there were so many contaminants in the city gas that the heat exchanger would clog up quickly with water, CO2, mercaptans, and god knows what else. We also had to keep the LN2 pressure about 80 psi with a relief valve so that it couldn't freeze the GNG, and that added more hassle to running the system without automated controls. When we scaled up we just pulled a dewar on a trailer to an LNG fueling stating in Lancaster and swiped a credit card to fill up, MUCH easier, we quickly re-learned that processing chemicals instead of buying them was a bad idea.

[@JohnMuz1]

🎉 HEY HEY 🎉

[@holographicman]

💕

[@andrewpyrah]

A bit of hey hey, then some hullo . A good Saturday

[@cramalotinn354]

🎉❤👌

[@markholmes5695]

@@andrewpyrahnot as much as Scott 😅 HULLLLOOOOOOO

[@MarcusHouse]

@@JohnMuz1 👋

[@wolfgang617]

Ah, Saturday afternoon sat down with a cup of tea and a biscuit, and the latest video from Marcus. Pure joy. Life is good.

[@MarcusHouse]

@@wolfgang617 Happy Saturday!

[@gundolarry]

You're an awesome human for that. Good on ya!

[@doncogswell9596]

Marcus...well done. You always make the difficult easier to understand. I think in the not too distant future, all propulsion will be replaced by something we haven't even thought of yet.

[@totally_lost1602]

Hi Marcus ... KISS engineering based on 1st principles yields very simple solutions to these problems. First keep both propellants at different pressures so the boilding points are identical, and solve the freezing point problem by design (IE they both ARE NOT 6 bar). Second in large tanks convection induced natural pumping between the hot side and cold sides of the tank in space will provide a passive version of active cooling by design (E convection circulation inside the liquids). Lastly either a solar electric, or thermal "steam" engine, can provide an active compression pump to recondense propellants back to liquid form from boil off, simply using "free energy" from the environments temperature differentials. Tumble/roll/spin the craft in space to balance average temps on surfaces, while choosing the best side to the sun when landing on the surface of the moon and mars.

[@eyesuckle]

@@totally_lost1602 Nice summary of solutions!

[@gregedmand9939]

Never forget that the best insulation is a vacuum. I would not be at all surprised to discover it is used at certain points in Starship and booster construction.

[@Vinlaell]

If I didn't have such mechanical forces on the tanks

[@AdrianBoyko]

@@VinlaellYeah, these things are basically Pepsi cans

[@r0cketplumber]

The downcomer and major fuel lines can be vacuum jacketed to isolate them, it's standard practice in lots of cryogenic systems.

[@imconsequetau5275]

Vacuum is also great for sun - shades !

[@PDLM1221]

Wow! That piping is a piece of art! What an engineering nightmare the people that figured this out are definitively amazing.

[@andrewrozario5127]

I love the periodic Marcus House deep dive videos! Some of my favorites.

[@lawrencerubanka7087]

I think this is one of your best videos. Your explanations and discussions of the challenges and possible solutions were very interesting. Thanks for your excellent content!

[@johnpagan9315]

Thanks for all the engineering details. I was able to follow the explanations and appreciate the challenges. Great job!

[@SabbaticusRex]

To solve pressure needed and the sloshing problem I always imagined either a large bag or plunger system to maintain needed pressure and keep slosh to zero . But that would weigh a bunch I suppose , and a bag would be eaten unless made of fancy stuff . I'm sure there is a clever yet simple way to fix these issues -- looking forward to hearing about them soon .

[@PS3PS3PS3PS3]

As a commercial refrigeration technician, the laws of thermodynamics topics are strong in this video! Interesting stuff!!

[@MarcusHouse]

Thank you!

[@totally_lost1602]

Hi Marcus ... KISS engineering based on 1st principles yields very simple solutions to these problems. Keep both propellants at different pressures so the boiling points are identical, and solve the freezing point problem by design (IE they both ARE NOT 6 bar). In large tanks convection induced natural pumping between the hot side and cold sides of the tank in space will provide a passive version of active cooling by design (E convection circulation inside the liquids). Either a solar electric, or thermal "steam" engine, can provide an active compression pump to recondense propellants back to liquid form from boil off, simply using "free energy" from the environments temperature differentials. Clearly the best part is no part, if other solutions are enough. Tumble/roll/spin the craft in space to balance average temps on surfaces, while choosing the best side to the sun when landing on the surface of the moon and mars. Pointing the aft engine bay into the sun, exposes different and CRITICAL engine parts to extreme temp differences and thermal gradients - Much better to choose pointing the nose into the sun when the solar energy is spread across a MUCH larger area, where thermal differences and thermal gradients have very little impact on the craft. The nose end is already designed for these gradients due to reentry plasma, the engine end less so with smaller tubes/wires that lack thermal mass to absorb high temps.

[@professor-viewsalot]

Well woww! As we all know, Tim set the benchmark (and Dam-high it was too!) for presenting 'Team space' information to us. As the years passed and Tim matured his channel (Everyday astronaut), he delighted us by starting to take deeper dives, Marcus & Space excentric slotted very equally into 2nd place with the very best of the rest all way back in the 'wannabee' section. I have said it several times in the last year, but every month Marcus expands the rapidly emerging gap behind him and he is now exclusively in second place to our forever hero Tim. As Marcus joyfully gets better & better, sadly Space excentric falls further and further behind. As Elon often reminds us, Space is difficult. As Space excentric and dozens of others all show us, Space reporting is also difficult! Well done Marcus. This level of quality is going to be hard to maintain, but I bet theres millions of folk wishing you well. Thanks Marcus,

[@MarcusHouse]

Glad you enjoy what we do. Thank you!

[@VikOlliver]

The original 90's Artemis Project was based on hydrolox. We proposed a centrifugal gas separator to avoid ejecting liquified cryogenics during zero g boil-off to reduce losses.

[@testpilotmafia862]

How does this work ?

[@VikOlliver]

@@testpilotmafia862 The liquefied propellants are mixed with the gaseous propellants because bubbles don't float in zero g. So the tank vent exits via a vortex chamber. The denser liquid is thrown to the outside of the vortex by centripetal force, where it is skimmed off and pumped back into the tank.

[@testpilotmafia862]

@@VikOlliver whoa! Is there a formal design I could look for online ?

[@VikOlliver]

@@testpilotmafia862 Sadly the Artemis Data Book was taken offline a couple of decades back, but there's a more recent paper by a different bunch. Web search for FEDSM2016-7793

[@AluminumOxide]

<a href="#" class="seekto" data-time="392">6:32</a> luv that steel mill scene

[@Kelnx]

About gave me flashbacks. I ain't working in one of those again. 🥺

[@ukbgoldi]

Love the snippet of green exhaust as the copper in the combustion chamber burns off <a href="#" class="seekto" data-time="424">7:04</a>

[@avanap8096]

Liked the last few frames at the end with starship going to warp. Live long and prosper!

[@MarcusHouse]

@@avanap8096 Was wondering how many would comment on that. ❤️

[@StromGarage]

Very nice physics "deep" dive. I really enjoyed it. It's the difference between "just" space news and technical background that makes me like your channel so much ❤

[@totallylegityoutubeperson4170]

Fantastic explanation of the tank farm process. My hat is off to you.

[@MarcusHouse]

Glad you enjoyed it

[@mcontreras90]

Wonderful presentation no irony comments or double standards suggestions. No reusable videos that made you tired to see them again and again. Really like this channel 😊

[@MarcusHouse]

Thank you very much!

[@martinkolar6527]

Love the new format! Learning about fundamental rocket science with so many actual examples and great footage is much better than learning about the latest girder or truck that was moved in Boca Chica

[@richardzeitz54]

Very interesting! I'd wondered about the boiling of oxygen and freezing of methane - that common dome sure looked sketchy. It's good to know that a)I wasn't crazy to wonder about that and b)there's a reason it works out. Starship development is one of the most important things going on in the world today as it will open space to us, so I always tune in every Saturday morning for your updates and deep dives. When I was a kid in the 1980s, Saturday mornings were for cartoons, now they're for Marcus House videos.

[@SpontaneousIntrospections]

Really love your deep dive format/approach on these focus videos, this one especially seemed to take us right along the pathway of problem solving and the pressure differential gave me a lightbulb moment too! Hope you're enjoying your well earned break, thanks for keeping us "fed" while you're away!!

[@ariel.maciel]

Thanks Marcus, this video was really helpful to understand some of the next steps and the new challenges that SpaceX will have to face when embarking on its journey to the moon, Mars or beyond. You gave me a lot of information that I didn't have in mind.

[@michaels.3709]

<a href="#" class="seekto" data-time="570">9:30</a> - Space is cold. Stuff in space is _not_ cold (if there's any heat source near/in them). Easy, simple heat transfer is something we take for granted here in Earth, inside a fairly dense atmosphere. You start removing the stuff that can carry away heat and you find out quickly that heat management becomes a problem that requires an engineered solution.

[@colonbina1]

Mind-blowing! Thanks for this deep dive

[@Cookie-cn2jc]

Great explanations. Incredible complexity.

[@jollygoodman7049]

This was a sophisticated discussion involving thermal dynamics and other sciences. Generally, people do not get exposed to the complex engineering challenges in producing technology like this - rockets, propellant storage, material science, space travel, etc. Nice job Marcus and team in making it understandable.

[@MarcusHouse]

Thank you.

[@jonesrichardmr]

The main reasons something like the ISS has radiators is a lack of convection in space. There is no other way to bleed heat, as there is no air to carry it away, so radiation is the only cooling option.

[@r0cketplumber]

Another way to prevent fuel freezing is counterintuitively to add some ethane or propane. These can make a eutectic mixture with methane with a freezing point as low as 72K and only very slightly reduce Isp while increasing density.

[@ErikSanders]

Somehow.. I always feel smarter after watching these types of videos.... Great video.

[@michaelross8734]

Unbelievably complicated, fantastiicslly skillful rocket engineers,wish i was half as clever as those guys 👍

[@TheSirjull891]

A great video as always Marcus. Your positive energy on my Saturday morning is always appreciated.

[@teyton90]

the best, most interesting video I have seen from you. and I think I'm close to having seen them all!

[@MarcusHouse]

Wow, thanks!

[@gilbhedy1]

Love your humility Marcus... This one was eye opener for me. Your explanation is very appreciated.

[@richiehart7858]

There is no reason for liquid methane and liquid oxygen in their tanks sitting on the launch pad to be at 1 bar of pressure. They have to be at a much higher pressure for the vehicle to have structural integrity, especially when loaded and that pressure in the booster has to support the entire weight of the loaded ship.

[@jip5889]

Yeah! The tanks are referred to as pressure vessels and operate at a pressure above one bar.

[@EveryoneWhoUsesThisTV]

You can imagine how much more of a problem this will be for the orbital tanker. Going from hot to cold every 45 mins or so..... Storing both propellants for days... weeks? Cryogenic propellants are great for reaching orbit, but once you're up there and using refueling methods, you want to switch back to storable room temperature propellants... Like Kero/HTP or Alcohol/HTP (for reusable engines) - both combinations are hypergolic, but aren't expensive or too toxic. They can be stored in bladders for easy propellant transfer. Plus HTP is multipurpose, it can serve as oxidizer, radiation shielding, RCS monopropellant and for life support to create heat, oxygen, water and electrical energy - which is useful for long space missions. :)

[@michaelmicek]

I would find discussion of cryogenics easier if the temperatures were reported in kelvins.

[@marcwilkins8787]

Thank you Marcus for calling covering this topic. Very informative and allows me to understand the design challenges that SpaceX is facing!

[@jasonscaf3840]

As an Australian, the way you said 'Aluminium' at around the <a href="#" class="seekto" data-time="400">6:40</a> mark just broke my heart.

[@testtest648]

Al-you-mini-um.😅

[@ewetoob1924]

At least he did not use American units, like BTU per yard farenheit :-)

[@DavJumps]

@@ewetoob1924 We call 'em "Freedom Units" 'round he-ah.

[@jasonscaf3840]

@@DavJumps 🤣🤣🤣🤣🤣

[@shauncurtis4398]

It’s almost enough for me to instantly unsubscribe. He is from Tassie though, they’re not proper Australians anyway.

[@Muny]

Excellent video today Marcus. I think you struck a nice balance between technical depth and approachability.

[@dog-loverjohn1379]

Super deep dive into a fascinating topic, Marcus, thanks ever so much! I hope you and your family are having a great well-deserved vacation!

[@gregedmand9939]

Never forget that vacuum is the best form of insulation. I would not be surprised if it is used in several areas of Starship and booster design.

[@charleslivingston2256]

No convection or conduction through a vacuum (although conduction through the walls), but it doesn't block thermal radiation at all

[@vicroc4]

​​@@charleslivingston2256 Thermal radiation is the least efficient method of heat transport, and not by a small margin. It's why ISS has such huge radiators, because it's incredibly inefficient to dissipate heat by radiation. Edit: As discussed in the video, I should point out.

[@charleslivingston2256]

@@vicroc4 when surrounded by the vacuum of space, that is all there is. The difficult thing is dealing with all the incoming thermal radiation from the Sun and to a lesser degree, the Earth. For JWST, the heat shield blocks those two plus the Moon, but JWST needs to be at a cooler temperature than the fuel depot. The real challenge for the fuel depot is the relatively high freezing temperature of methane. That means just using a sun shield could get too cold. A large array of solar cells could shield the depot from external thermal radiation and provide power for active cooling and heating. Transferring heat from the colder LOX to the liquid methane may be necessary and would have to be active, not passive

[@vicroc4]

@@charleslivingston2256 True, but that's not what OP was talking about.

[@imconsequetau5275]

​@@charleslivingston2256 For the orbital propellant depot, it is likely necessary to insulate both the common dome bulkhead and methane downcomer tubes. A vacuum insulated double-wall technique is likely needed for the methane downcomer pipe, plus methane circulation or heating inside. As for the sun shade, it will need to totally shade the oxygen tank and partially shade the methane tank. There will likely also need to be a Mylar radiation barrier for blocking Earth glow.

[@AM-hf9kk]

Regarding the issues of long-term storage: that's another beautiful thing about SpaceX' approach compared to the legacy approach. SpaceX is addressing ONE issue at a time in physical hardware, and finding ways to make that one solution profitable. Legacy launch and space system providers spend decades simulating DOZENS of issues at the same time, knowing that they will NEVER be profitable but it doesn't matter because those government contracts will just keep pouring in.

[@RaySqw785]

spaceX received $25 billions last 15 years from US Gov , it took 10 years to land a booster on the worst rocket in history regarding Co2 pollution Falcon 9, and Sapcex annouced they'll be on Mars in 2022, 2 years later they can't even reach the LEO at 400kms orbit without burning the vehicul, Appolo 4 reach and came back to the moon at the first attenpt! Spacex is the worst ever space company regarding tech and announced acheivment of the space history , then still getting billions from US taxes payers!

[@Ulrich.Bierwisch]

One issue at a time is the most stupid way to develop a complete system like a spacecraft.

[@davidhuber6251]

I think the point is not biting off too much at once. If they focus around the core sets of problems without worrying about esoteric aspects that will happen down the line, they can more easily find the limits of the core set of parameters. They obviously need to work on hundreds of engineering challenges just to get off the ground without exploding. The hundreds of challenges that will arise on the long trip to Mars can wait until they know what it takes to get to the start of the journey.

[@Ulrich.Bierwisch]

@@davidhuber6251 You can do journeys like the Franklin Expedition or Andrée's Arctic balloon expedition. Just start and find out what doesn't work on the way but space is a lot more dangerous than the Arctic or Mt. Everest.

[@jamskinner]

@Ulrich.Bierwisch It’s not really one issue at a time. It’s solving different problems with iterative testing.

[@davemason6501]

I've been thinking about the fuel depot. With a shade like the one on the JWST, that covers say 270 degrees of the depot, should help a lot. Half of so of the orbit is in the dark which has to help. Getting the problems solved with keeping propellants liquid and reducing boil off, should help a lot on the trip to the moon and beyond. Really enjoyed this episode.

[@meinking_sensei3807]

A shade like JWST would be to overall to complex. Pointing you're Nose to the Sun so the actual Tank parts don't recieve direct sunlight + insulation like on the Shuttle main tank + Cryo coolers should get the job done

[@executivesteps]

@@meinking_sensei3807Don’t forget the the Earth radiates at 300K, dayside AND nightside. It also takes up a huge solid angle while in low Earth orbit.

[@r0cketplumber]

In Low Earth Orbit the radiant heat from the Earth is almost as bad as that from the sun and fills half the sky, making it difficult to avoid.

[@meinking_sensei3807]

@@r0cketplumber nuh the sun is much much worse

[@slevinshafel9395]

Can work but must have polar orbit. Because i dont know thow much heat radiate Earth. and having GasStation in polar orbit can be god and bad. because you have to make a plan mision acording to refueling time wich make it hard when you come from the Westo to the East and the gaspump come from North to the South, and the speed there are 27.000km/h and are diferent trayectory. We keep working on it and betwen 9.000.000.000 humans in this planets we can figure it out...xD

[@simonowen1956]

Thankyou again for such a well researched video. Always delivered in such a great way. Never disappointed.🎉

[@billsimpson604]

You had better hope that guy welding inside that tank is really good at his job. A weld defect would be bad. Good luck making all that methane on Mars. You are going to need a lot of big machines and a huge power source to do that. All that will need to be built while wearing bulky space suits.

[@bernieschiff5919]

Setting up the fueling station(s) on Mars will probably be totally automated, with robot machines and systems doing the work. Over time, an adequate supply of fuel will be available for when the first ships arrive. Overview and direction will be time delayed so construction will stop at intervals for review and updates. A reliable power source like nuclear is probably the way to go on Mars but no mention of it officially yet. Same holds true for active cooling and life support for longer trips to Mars and back, nuclear power is probably the answer. Good video raising the questions of temperature and pressure.

[@danapeck5382]

Thanks, really great to have this more technical content from you and your team. Know it's hard to assemble, hope to see more. All the best

[@BMrider75]

I've just rewatched this video 5 weeks later, as it was referenced in the 24th July '24 vid. Seeing the separate downcomer pipes on their jig makes sense too.

[@Jamie_Elizabeth192]

Hey hey. Another great saturday morning video. I always look forward to seeing these. Thank you for making it so I don't get the shakes until your return.😮

[@raedwulf61]

Thanks for explaining this. I don't think I have ever heard this before.

[@JeromyBranch]

Ok so stupid question here...would it be possible to run a pump off of a Stirling engine? I mean, you have a gargantuan temperature difference available at pretty much all times in open space, and a Stirling engine requires zero fuel. I do realize a Stirling engine is not powerful. But it would not take much to produce a little more pressure, right? No? See, I told you it was a stupid question.

[@sadstrangelittleman0]

Stirling engines are inefficient and have too many moving parts. They would add more weight to the system than other solutions with little benefit

[@HALLish-jl5mo]

Do you have a giant temperature difference? Sure, sunlight is very hot, shadow is very cold… but vacuum is a very good insulator. If you don’t have anywhere to shed the heat too, it’s useless.

[@JeromyBranch]

@@HALLish-jl5mo just going by what was shared in the video. That one side of the space station is very hot, the other side is very cold. The only difference is direct solar radiation on one side and not the other.

[@johnpendred6926]

Enjoyed that. My brain feels nourished! Cheers

[@davidfriedline7525]

Great job explaining all that Marcus ! Peace and love !

[@benspeicher9218]

Great video. I think this is my favorite Marcus House video yet.

[@emorymeek]

Awesome deep dive! Thank you!

[@imconsequetau5275]

For the orbital propellant depot, it is likely necessary to insulate both the common dome bulkhead and methane transfer pipes. I would prefer to empty the large downcomer except during launch and landing. Otherwise, a vacuum insulated double-wall technique is likely needed for the methane downcomer pipe, plus methane circulation or heating inside. As for the sun shade, it will need to totally shade the oxygen tank and partially shade the methane tank. There will likely also need to be a Mylar radiation barrier just for blocking Earth glow.

[@neilm9400]

When starship was presented to NASA as a solution for moon landing, I would have imagined the fuel issue would have been at the front of everyone's mind. Designs, numbers would have been presented... Let's hope so 👍

[@MarcusHouse]

@@neilm9400 all I know is that I haven't seen any such detail.

[@Lynx-vi3bi]

@@MarcusHouse As a SpaceX employee, I can say that the public gets to see a small fraction of all the information we have and are working on.

[@garyc1384]

@@Lynx-vi3bi We see Elon's genius speeches to SpaceX staff, which numbed you all into silence with its brilliance......

[@garyc1384]

@@MarcusHouse They're called blinkers, Marcus.

[@MarcusHouse]

@@Lynx-vi3bi Yes, I'm certain that is true.

[@bs_serpents]

Another great video! Loved the Tank Farm breakdown. Thank you!

[@kstaxman2]

Your work is as always amazing. Best breakdown of the temperature storage issue for the layman I've ever seen. This shows one of the many problems SpaceX has to work with.

[@MatthewElvey]

Awesome, awesome long video. On rewatching a second time, I noticed the animation and "Extreme Temperatures" label around <a href="#" class="seekto" data-time="1058">17:38</a> is all wrong. Should refer to the +120/-160 range, but don't. Off to look for videos about why the ISS is warm/needs those coolers.

[@igorl46]

Well done, as always!

[@3gunslingers]

Until <a href="#" class="seekto" data-time="848">14:08</a> I thought you had lost your mind. Pressure is the first thing that comes to mind when dealing with boil-off. Very satisfying end to this video, tho :)

[@MarcusHouse]

Yes, we need to first explain the problem and the challenges before talking about the solutions with pressure to widen the gap between the boiling points.

[@Vodhin]

You know, I think you are the first to point out this problem of one liquid freezing the other liquid inside Starship. Goodonyer for that, mate!

[@oliverknight26]

Love your videos man keeps me happy

[@malcolmstreet1]

Fascinating piece on yet another factor in rocket design I hadn't come across.

[@cfromafar]

Been following your channel for a long time, Marcus. Your content is just getting better and better. Thank you for your hard work with your team.

[@MarcusHouse]

Thank you!

[@bgdx.5049]

Excellent thermodynamics lesson. You rock!

[@kozakis726]

this complexity problem will be benefits space exploration for sure, the fact they're working solutions to this and not run away from the problem

[@INiallAnderson]

This is an insane amount of detail! Ty Marcus!

[@francoisdunoyer4341]

A very good way to cool down the ship in orbit would be to put the reflective side toward the sun and the heat shield in shade. It will work exactly the same as an emergency blanket (or the Multi Layer Insulation used in satellite): one side is super reflective, and the other side super emissive (capable of big radiative exchange). So if you put the reflective side toward the sun, no radiative exchange will occurs, and the other side will exchange by radiative means with the cold space. Being the hot source, the ship will cool down naturally. The best way they can do that is like in the video having the reflective side on the bottom with the engine bay, and radiate the heat on the hole body

[@zarl5238]

I tried following your explanations Marcus, but this was one of the reasons I never took any chemistry classes while in college. But thx-at least I now know how difficult powering rockets can be for engineers.

[@NOM-X]

Thanks Marc for getting the message about Fahrenheit. Love it! Better understanding. Keep the great episodes coming. - NOM

[@serratededge4154]

i'm wondering how convection works in micro-gravity, with a hot and a cold side. maybe temperature control of the fuel is as simple as keeping it stirred, pumps, convection, rotation. and controlling the angle towards the sun to regulate the amount of heat collected

[@hesse6249]

Thank you Marcus, excellent explanation 😊

[@LindaMadlala]

Thank u Marcus for this deep dive into this existential challenge for Starship long duration missions. Am sure folks at SpaceX have a solution but either way it is a great commercial viability challenge.

[@cbaesemanai]

I am going to go out on a limb here but I have full confidence in the smart people at spacex to solve any issues they may run into .

[@MarcusHouse]

@@cbaesemanai Oh likewise. I'm not for a minute suggesting they don't have a solution to this challenge. They've just never shared it publicly.

[@beakytwitch7905]

Nice that you traversed what to us is a new topic. Thank you! ❤

[@Wandering_John]

Another great Deep Dive! Keep up the good work!

[@gccchc2449]

Love the deep dive videos. So much to be sorted along the path to multi planet people. My 2cents. Inflatable shields from vented gas. Plus. A steady roll to create an even 'all over tan'. An engine rear end inflatable solar shield would be used in the last stages of Luna landing.

[@crazyj0ranch1]

Excellent research, need more of this!

[@michaels.3709]

Perhaps an "autogenous cooling" approach could be used for short-term missions, where some fuel is sacrificed as coolant, cycled through some system that selects for higher-temperature molecules, (like a semi-permeable membrane of sorts)? I know this is going full Maxwell's Demon here, but that would be really neat to see a passive cooling system that works like this. I'm also wondering if the autogenous pressure mechanism could also be used to overpressure the fuels for long-term storage, over the 6 bar they're normally kept at. You'd need a dedicated high-pressure version of the starship, but for long-haul missions (eg. to Mars) you'd already be bringing extra fuel with you.

[@prome3us550]

Hey Marcus, hope you get to see this. On the topic of passive temp control, how much of a benefit would be gained from simple rotation? Like a bullet being spun by the rifling of a gun, if the starship were to simply roll (not even at a significantly fast rate taking the thermal inertia of the ship's outer skin into consideration) it would continually expose any spot on the outside to alternating chilling and heating from radiation, getting the whole thing to average out nicely like a rotisserie chicken... It would obviously average out at different values depending on distance from the sun and thus need active systems to lock down the final desired specific temp, but it would help take away a large part of not only the difference in temps between sides but also the mechanical stresses that come from such a wide temp variation around the ship's outer surface Would love to hear your thoughts on the idea

[@michaelpetty8867]

Well, if they only need the header tanks for landing. Then they only need to focus on keeping those liquid. Passive would be easier since the surface is drastically reduced. I imagine even a higher pressure would help. And possibly an active cooling loop of some kind that kicks in when boiloff psi builds. So no loss. Obviously you would need some kind of emergency psi release, but it wouldn't be venting out unless it going to pop. Maybe even a cooling loop back into the main tanks that could also accept some boil off for possible reclaiming. That's less likely on reclaiming though.

[@slartibartfasttynsol420]

For both the fuel depot and the long term flight to mars, I was wondering about the inflatable habitats by Bigelow being tested on the ISS. If a ring of these were added, it would provide an insulating barrier to prevent the radiant energy from the sun and earth directly hitting the tanks. Gas is a poor conductor of heat, and the inflatable barriers could be reflective.

[@sd100-f4n]

, it's theoretically possible to use a magnetic field to protect a spacecraft from re-entry heat, but it's still largely experimental and requires significant engineering advancements. Here's the concept: 1. _Magnetic shield_: Generate a strong magnetic field around the spacecraft using electromagnets or superconducting magnets. 2. _Plasma deflection_: The magnetic field would interact with the plasma (ionized gas) generated during re-entry, deflecting it away from the spacecraft's surface. 3. _Heat reduction_: By deflecting the plasma, the magnetic field would reduce the heat flux on the spacecraft's surface, potentially eliminating the need for traditional heat shields. Challenges and limitations: 1. _Scalability_: Currently, generating a strong enough magnetic field to protect a large spacecraft is a significant technological challenge. 2. _Power consumption_: Creating and maintaining the magnetic field would require substantial power, which could be a concern for long-duration missions. 3. _Stability and control_: Maintaining a stable and controlled magnetic field during re-entry would be crucial to ensure effective protection. 4. _Materials and design_: The spacecraft's materials and design would need to be optimized to withstand the stresses and heat generated during re-entry, even with magnetic protection. Researchers are actively exploring this concept, and some promising results have been achieved in small-scale experiments. However, significant technical hurdles need to be overcome before magnetic shielding can be used for practical spacecraft re-entry protection.

[@GeorgeWMays]

Excellent show. Thanks;. Appreciated.

[@NeptunesLagoon]

As they are needed, each issue will be addressed and alieveated… love your vids, especially when you get with Manly and other people in the field… 😊

[@MarcusHouse]

Glad you like them!

[@CMEVR2]

Great video Marcus! Really well researched.

[@isaacmallinson2654]

Hey Marcus, the thing I'm most worried about is where is the infrastructure needed to sustain Moon and Mars bases? I haven't seen anything tested, it's all just mock ups and CAD drawings at this point... kinda cutting it close for SpaceXs goal of reaching Mars in just a few years!

[@vinceelliott4362]

Outstanding work once again Marcus :) Thank you sir.

[@oldfatman4639]

A brilliant segue. Well done.

[@yfarrell]

I love your videos Marcus. I was worried about this same problem so I started to look up the temps too, but I didn’t know what pressures they were using. You read my mind! I was trying to determine the cause of the icing problem in the last few missions because they kept having engine relight problems due to ice. In flight 4 they still lost 2 engines so I wonder if they are still working that through. I hadn’t even gotten to the relight in space issue so Thanks for your insight. Thank you Marcus!

[@MarcusHouse]

Thank you! I believe a lot of the ice issue currently reported is water ice but that is another problem entirely.

[@daviddenley3512]

Thanks for another very interesting video you've made for us, this is getting very exciting!

[@Kevin_Street]

Thank you for this video, Marcus. I love it when you guys do these deep dives. And you're totally right that fuel boil-off is one of the greatest challenges SpaceX faces on any long duration space mission. They must have some ideas on the drawing board, or they wouldn't have gotten the lander contract from NASA.

[@MarcusHouse]

Oh, SpaceX has this fully planned I'm sure. We just don't publicly know how they are solving these problems. I find it fascinating to research these topics.

[@rustyfox81]

6 bar is the pressure in the head space above the liquid. But the actual pressure of the liquid is much higher at the bottom of the tank due to the weight of the liquid

[@mikebrant192]

Marcus, thank you for finally explaining to others the intricacies of cryogenic fuels. I've been trying to get someone to do this for well over a year. I worked with cryo fluids, and knew of the problems, and it was frustrating. Now, please discuss hydrogen stress cracking one of these videos.

[@forestgiest1380]

<a href="#" class="seekto" data-time="682">11:22</a> That's only because it has open cycle engines that spew unburned propellent. It's not some inexorable characteristic of the fuel that makes it inferior. it's engine design.