Thermal Protection System - Starship vs. Space Shuttle

SpaceX is working on improvement and development of many aspects of Starship, but one question to be yet answered is their solution to thermal protection.
In this video, we deep dive into the types of thermal protection, and whether can SpaceX avoid problems that haunted the NASA's Space Shuttle program.
0:00​ - Intro
0:58​ - What is the problem?
3:48​ - Blunt body solution
6:04​ - Ablative heat shield
7:56​ - Heat sink
9:08 - Starship vs. Space Shuttle
13:40​ - Space Shuttle tiles

[@rays2506]

The physics behind those HRSI tiles and the Starship tiles is called Mie scattering. The tiles are made from ultrapure silica fibers (silicon dioxide, or quartz) that are about 1.5 microns in diameter. A human hair is about 70 microns diameter. The fiber diameter is selected to match the wavelength of the thermal radiation at the maximum use temperature (2400F, 1316C). The fibers scatter this radiation far more efficiently than they absorb the thermal radiation. Two parameters characterize this scattering process: the backscattering coefficient and the absorption coefficient. For Lockheed's LI1500 tiles, the backscattering coefficient is 223 while the absorption coefficient is 0.3 at 2400F. So that tile scatters thermal radiation about 743 times more efficiently than it absorbs that radiation. That's the secret behind the tiles. Side note: My lab at McDonnell Douglas developed the equipment for measuring those two coefficients way back in 1969 during the early conceptual design phase of NASA's Space Shuttle program. Those coefficients are measured in units of inverse surface density (ft^2/lb).

[@spaceflightexplained360]

Thank you for the wonderful comment. I need to pin it up. I wish I had somebody with your knowledge to consult with, and I hope that the video wasn't too unpleasant to watch for you.

[@juanixinauj]

It's always fantastic when you have access to the insight from someone who actually worked with it. Thank you very much for sharing this!!

[@rays2506]

@@spaceflightexplained360 Your video is very good. Keep it up.

[@SmogandBlack]

I know nothing about this matter (I am a Physician...) so please forgive me if my questions (as I suspect) will sound laughably dumb:1) is this technology somehow similar to Aerogel? 2) how much will this tiles be consumed / worn by heat? Nice to see you back Vojtech Holub 😊

[@spaceflightexplained360]

​@@SmogandBlack That is a great question! The way I understand it, it is actually pretty close to aerogel, slightly lower air ratio, and with additional coating, and as the above commenter explained in detail, made specifically to radiate away heat. But the basic silica composition is very similar.

[@juanixinauj]

Hey! What a surprise! I'm glad you are still doing videos: well explained ones, with maths that are reasonable to follow and always so informative. I didn't imagine the radiative power of the TPS tiles!! I can happily say: I learned something today! Thank you!!!

[@spaceflightexplained360]

Thank you for the compliments! I am still doing the videos and I am not planning to stop, especially when there is a good topic. My time is precious and I am really inefficient when making the videos...

[@juanixinauj]

@@spaceflightexplained360 I'm glad to read you'll keep on making them! And hopefully you'll gain in efficiency with passing time! Cheers!

[@sandeepkapare]

Stumbled upon this video and immediately subscribed to your channel. Was amazed to see the science you explained that too without making it too boring and still maintain it's entertainment factor. Keep up the good work. Can't wait to see all your previous videos.

[@spaceflightexplained360]

Thank you Sundeep! I think that my previous videos are pretty good too :)

[@TheFelmaster]

Much more in depth than I was expecting. Great job!

[@spaceflightexplained360]

Thank you sir! That is what I do :D

[@per619]

Terrific job. I didn't try to follow all your math because I understood the principles and results with your excellent descriptions.

[@jackforman6385]

you are defiantly on my favorites list. I am being challenged to learn how space flight works and seeing there is more to a space ship than being a boom stick. Keep up the wonderful effort

[@spaceflightexplained360]

Boom stick going up in the right way without exploding is definitely a good start! But the nature of space is deadly, nothing personal, but it wants to kill you in every possible way :) So it is important to understand all its ways to be able to prevent it.

[@jonathansidi3149]

A brilliant and very informative video, as usual. Hope you get the thousands of views you deserve

[@spaceflightexplained360]

Thank you Jonathan! If it is good enough and you guys like it, I am sure I will!

[@inapond13]

Great video. I had wanted to know more about the thermal protection. Thank you.

[@spaceflightexplained360]

I wish I could go deeper here, but the field is based on simulations, experience, and testing. My back-of-a-napkin approach really fails here...

[@mortallychallenged]

Very informative and really dives deep, I really appreciate the effort put in and it gives a lot of unique insight that you just can't find anywhere else. Thank you!

[@spaceflightexplained360]

Thank you sir!

[@koenkegel]

Nice video again Vojtech Holub! Hope you are doing well! Keep it up!

[@spaceflightexplained360]

Hi Koen, good seeing you again! I am swamped between my full time R&D job and starting the ThinkOrbital...

[@chemicheto]

Man, I just found your channel, I love the depth you went into to explain everything

[@spaceflightexplained360]

People like you are the reason why I do videos from time to time! Thank you, I really appreciate the positive feedback

[@aksh_x_]

Amazing explanation! Honestly you're underrated

[@spaceflightexplained360]

Thank you Aksh! I am actually really happy about the passionate viewers I was able to reach with only 7 videos. I just wish that more people would be as interested in other space endeavors and physics than those related to Starship

[@josephparker3033]

Wonderfully done, thank you!

[@steveford4055]

Numbers!! So much of the space(x) streaming bonanza that's following their insanely paced prototyping phase, seems to forget the explanation with the digits! Beautiful video man! Love it! Definite subscribe!!

[@spaceflightexplained360]

Numbers!!! If only there was a way to quantify things :)

[@richardcarlson2644]

You sir are a treasure of knowledge!!! I remember your first video it was very good but you've progress in presentation is great! I believe your the most knowledgeable person online! Look forward to your Next Thank You

[@spaceflightexplained360]

Thank you for the compliments, but I have to politely disagree. I just like to learn and sometimes make a video about something new I learned with a slightly different angle and depth than others. For example Scott Manley can discuss extremely technical topics from top of his head for hours. My brain is not even close to the capabilities of his.

[@nelsonwierzbinski9559]

Future Aerospace Engineering student here, Your videos are really informative, clear and concise! A little advice I can give is to articulate more and have more variation in your tone. Goodluck with the growth of your channel!

[@spaceflightexplained360]

Thank you Nelson! I'm a secret robot, that is why :) Really appreciate the advice!

[@theonlynugster]

Thanks for the excellent video’s! Really nice and informative without going too much over my head.

[@spaceflightexplained360]

Thank you Michiel! It is a bit of a balance, but my overall goal is to bring the physics and problems of Spaceflight little more understandable, so that I, and others with decent physics intuition can see why certain decisions are made.

[@canonbow5357]

your humour got you a subscription today. thanks for the laugh & technical details

[@spaceflightexplained360]

Haha, thank you fellow appreciator of dry badly acted humor!

[@mattkerle81]

Just found this now, great video!

[@spaceflightexplained360]

Thank you Matthew! I haven't been very active lately...

[@progkarma944]

I really like the "Back of the Napkin" calculations! :)

[@spaceflightexplained360]

Thank you! They can't tell you how to engineer things, but they will tell you whether an idea might work or not :)

[@masonjohn4433]

I never considered that the shock wave would be heating the hull through radiation. For some reason I always thought of it as a convective heating problem. Thanks for making such insightful videos! And thanks for the math!

[@spaceflightexplained360]

Thank you for the compliments! As the plot in the video shows, for LEO speeds, convection is still the main driver!

[@Alex.Adametz]

As always, very informative and well presented!

[@spaceflightexplained360]

Thank you Alex!

[@agamemnongames886]

Thank you for the vidoe. It is really informative.

[@spaceflightexplained360]

Thank you!

[@KhurramJhumra]

Excellent video. Well explained concepts based on facts and numbers. Great job!

[@spaceflightexplained360]

Thank you for the compliments Khurram!

[@cwulfe1]

You're back! Yay!!!

[@spaceflightexplained360]

I am! The frequency will be very irregular due to my time limitations, but I'm not planning to stop :)

[@danthemanzizle]

Another really interesting video. thanks! Back of the napkin math is probably my favorite part. Its cool to play around with the variables and see what happens.

[@spaceflightexplained360]

Exactly. Gives a real understanding without having to get an exact answer!

[@quantumspinup7418]

Excellent video. Thank you.

[@spaceflightexplained360]

Thank you sir!

[@edwardzieba7887]

We already know the current (no guarantee they won't change) that the Starship tiles are not just similar to the STS tiles, they are near identical: sintered purified silica fibre, glazed with Borosilicate reaction-cured glass, and then waterproofed with a Silane mixed with Acetic acid (minor difference here: Starship uses methyl-trimethoxy silane, STS used dimethylethoxy silane). The original HRSI tiles, not TUFI, not HETC, and absolute 100% not TUFROC. This information if from the Florida Department of Environmental Protection facility inspection report of the tile manufacture facility on Astronaut Blvd.

[@spaceflightexplained360]

Thank you for the additional info! That was my assumption as well, and we should expect some iterations on improving the mechanical properties. But I would not expect groundbreaking improvements in the near future.

[@aljazmesec6797]

glad i found this channel

[@spaceflightexplained360]

Thank you! I wish I had more time now to continue making more

[@adrian.banninksy]

Great video, that was worth waiting for! I really like this approach of the "math" behind spaceflight. I once wanted to study aerospace engineering at the university of Delft, in the Netherlands. But it went different and I got a masters degree in mechanical engineering and industrial management. For 30 years I work in the system development- and production industry (so engineering and production of complex modules and parts out of exotic materials). I work for semi-con, medical and aerospace. These video's are very educational for me to understand the demand site. But beside all of that, they are just great to watch, because they are so very clear! Hope you keep continue with it!

[@spaceflightexplained360]

Thank you for the compliment Aad! The wait was due to me being busy with a new company I started (ThinkOrbital Inc.), to pursue my extremely ambitious passion project. Please take a look at "thinkorbital.com" and if this is something you would be interested in helping, please contact us, I would be grateful to talk to somebody with your experience.

[@adrian.banninksy]

@@spaceflightexplained360 Thank you for your quick respond. I certainly will check out the web site. It sounds interesting. We keep in touch!

[@GuardsmanBass]

I remember a good comment once that the Space Shuttle should have been impossible, but they managed to make it work. The resulting spacecraft, though, was so complex that if you tried to make any kind of major change to it, it quickly got out of control and you pretty much had to design a whole new spacecraft.

[@spaceflightexplained360]

It was in a way too capable thanks to the air force spy sat deployment requirements. At the cost of margins and, well, cost.

[@affinix887]

Such a good video. Im surprised, your channel will blow up soon

[@spaceflightexplained360]

Thank you sir! It will be hard with the glacial speed I make them :)

[@adrianmoisa2281]

Awesome new video! Glad to see you are still going strong!

[@spaceflightexplained360]

Hi Adrian, good seeing you here! I kept myself really busy and there was unfortunately no time for following up sooner...

[@adrianmoisa2281]

@@spaceflightexplained360 I'm also working on the new web platform. It will rock. I'll show it to you once I get closer to complete design specs.

[@skyhiker9669]

Excellent information! Thank you.

[@spaceflightexplained360]

Thank you sir!

[@alaskajdw]

Bravo. Well done

[@spaceflightexplained360]

Thank you Joel!

[@17cuzzo]

Great video !!! Keep up the good work

[@spaceflightexplained360]

Thank you Federico!

[@makespace8483]

Very informative. Thanks!

[@spaceflightexplained360]

You are very welcome!

[@clarencehopkins7832]

Excellent stuff bro

[@spaceflightexplained360]

Thank you Clarence!

[@bennybooboobear3940]

Love these vids! Please make more 😊

[@spaceflightexplained360]

Thank you Benny! I wish I had more time, but I started an aerospace company and it is eating most of it :-)

[@hanreswanepoel1166]

Great video!

[@spaceflightexplained360]

Thank you very much for the compliment!

[@rayratorres9361]

Great video

[@spaceflightexplained360]

Thank you!

[@cbeas4662]

Really good content. Thank you.

[@spaceflightexplained360]

Thank you!!!

[@KRGruner]

Well done!

[@spaceflightexplained360]

Thank you Karl!

[@KRGruner]

@@spaceflightexplained360 No problem. You are very good at this. Trying to catch up with your older videos now. You deserve a larger audience.

[@cabanford]

Your videos are fantastic ⭐⭐⭐

[@spaceflightexplained360]

Thank you sir, I really appreciate the compliments :)

[@stevenhorne5089]

I'm really glad to see people outside of the US becoming interested in exploring space. I'm hopeful that more countries, but more importantly, more companies will start to become involved the space industry. A truly global effort will bring down the cost of space exploration as a whole. The more people involved will increase the amount of ingenuity that mankind is know for. Sub''ed

[@spaceflightexplained360]

It is exciting time, and space by it's definition doesn't have borders :) I have to disappoint you on my part, I have been living in the US for the last 10 years :)

[@stevenhorne5089]

@@spaceflightexplained360 I'm not disappointed. I'm certain there are people in your family that you'll influence, and it'll grow from there. But it is important that people in other countries start to realize that you don't have to build your own ride to space. The age of renting a spacecraft to do space stuff has started.

[@thyandyr7369]

Good stuff

[@spaceflightexplained360]

Thanks a lot!

[@roger_is_red]

This video is great !!!! very very interesting.

[@spaceflightexplained360]

Thank you Roger!

[@elephantwalkersmith1533]

Great explanation!

[@spaceflightexplained360]

Thank you sir!

[@philippeferreiradesousa8673]

Thank you!

[@spaceflightexplained360]

Thank you sir for watching!

[@jedswift]

The silica tiles also have a propensity to absorb water. The water proofing had to be reapplied every flight, as it blew away during entry, adding significant labor during flight prep.

[@spaceflightexplained360]

Thank you for pointing this out! I am aware of the water issue on the Space Shuttle, but I didn't realize that Starship has to solve that as well!

[@austinmeyer]

Wow, amazing numbers! I kept converting things to horsepower to see how fast energy was being absorbed or radiated. TOTAL POWER DISSIPATED if spread out over 30 minutes of 1.7GW is 2.3 million horsepower...

[@spaceflightexplained360]

Yep! And I would assume that Starship's EDL will take less than 30 minutes...

[@ThinBlueLaneRVLife]

Amazing explanation, my friend.

[@spaceflightexplained360]

Thank you!

[@jeremyc1034]

Amazing

[@spaceflightexplained360]

Thanks Jeremy!!!

[@richardrigling4906]

Well done. good humor

[@spaceflightexplained360]

Thank you Richard!

[@aleksanderwierzejski1346]

Panie Wojciechu, dziękuję za profesjonalne materiały!

[@spaceflightexplained360]

Nemate za co!

[@Dave--FkTheDeepstate]

Great video, thanks! Is there anyway to recover / capture some of the re-entry heat/energy ?

[@spaceflightexplained360]

I think the main goal is to recapture as little as possible - it is such a crazy amount of energy that there is really no practical way to store it

[@brabanthallen]

Excellent and informative video. If we could somehow collect the heat that is being transferred away from the tiles during re-entry, and direct that energy directly into the flux capacitor (granted we could find and afford a Delorean), we could go back and save Starships SN8-11.

[@spaceflightexplained360]

Maybe that is what happened and they went back in time, but in parallel reality to avoid time travel paradoxes?

[@oldfrog17]

Your math was spot on, but there is a great difference between the tiles on the Space Shuttle and the Starship. The Starship tiles have a different ceramic composition, and are much stronger. Reusing Shuttle tiles would be a recipe for disaster. Elon did indicate that they do ablate and will have to be replaced after every 10 flights. Shuttle tiles do not ablate. Hull thickness is 3mm not 1.8mm. Some sections will be 4mm thick.

[@spaceflightexplained360]

I think there was some misunderstanding... 1) Tiles don't have infinite life span, they all need to be replaced eventually, whether it is Space Shuttle or Starship. 2) We really don't know what the exact performance of Starship tiles is, so in this video, I assume that it is the same as Space shuttles, but with different shapes and other advantages. 3) The 1.8 mm is not supposed the be the wall thickness, but and additional layer of the same weight as the titles would be. It is for comparison to highlight the power of the tiles compared to steel

[@oldfrog17]

@@spaceflightexplained360 Thank you for your response. The Shuttle tiles could be handled within seconds (Yeah from the corners only) because they were highly conductive and quickly moving the heat across all the tiles. Those tiles were extremely fragile, but from what I've read about them, where they were placed, they did not wear, but they did crumble away. Starship tiles are not conductive, and ceramic. They will keep the heat away from the backing, and hull - to a point since the Stainless Steel can take a lot of heat. These tiles will reach melting temperature and will wear. This ceramic was picked because of its strength, insulation, and melting temperature. Ceramics like all others have a binder which I have no idea what the binder is, but the binder has to have similar, but not so high qualities like insulation, and melting temperature, but increases the overall strength of the ceramic, and lower the fragility. I would assume that the ceramic tiles will be denser than the shuttle silicon tiles mainly for the reason to increase the strength of the tiles. I know this since I am a machinist and have worked with ceramics, and carbides which are a type of ceramic.

[@willyamcarkey717]

Vřelý pozdrav z Čech :) Super video!

[@spaceflightexplained360]

No nazdar :) Diky!!!

[@uranus9954]

Thats a very good and informative video man! Youve earned a subscriber!

[@spaceflightexplained360]

Thank you Uranus! :)

[@svenzockt6491]

General Kenobi. You are a bold one.

[@spaceflightexplained360]

Hello there!

[@hagerty1952]

The TPS developed for Dyna-Soar was also a passive/radiative design using non-load-bearing columbium panels coated with silicide (a dark black substance) to increase its black-body coefficient. There was a layer of matted quartz fiber insulation behind that and then load-bearing panels of Rene 41 super alloy attached to the vehicle's space frame (also of Rene 41). It was estimated that it could go 4 EDL cycles before replacement. The panels were relatively large with only a couple dozen over the whole vehicle thus not that time consuming to replace.

[@spaceflightexplained360]

Were these panels realistic? There must have been some reason why the Space Shuttle that came later had smaller and different tiles... And also unfortunately aluminum structure

[@hagerty1952]

@@spaceflightexplained360 - The panels had been quite extensively tested, or at least the materials had. The advantage was that the Dyna-Soar was a "hot-body" vehicle during reentry, i.e. only the cockpit and cargo space was cooled. The rest of the structure and systems were designed to operate at elevated temperatures. While the columbium panels would have seen the 2-3,000°C surface temperatures during entry, the structure behind it (the Rene 41 panels and space frame) were designed for temperatures of nearly 1,000°C. The cockpit and payload shells had a "water wall" attached that absorbed heat by phase change, and dumped it into a heat-sink that used the liquid hydrogen fuel to cool things down. This is all detailed in the book "Dyna-Soar" by Air Force historian Roy Houchin: www.arapress.com/dyna-soar-book/ The Shuttle, OTOH, was a "cold body" vehicle, meaning that the entire structure had to be kept at low temperatures so the TPS bore the entire brunt of the heat.

[@bradmcslow2091]

nice calculations

[@spaceflightexplained360]

Thank you Delfin!

[@njm3211]

Very informative. Another relatively cheap option is to use Inconel in lieu of stainless steel for greater heat resistance in selected areas. Don't know if it maintains adequate strength at cryo temps. Thanks

[@spaceflightexplained360]

I think there might be some issues with just using heat resistant metals 1) They are very heavy 2) Is thermal conductivity is very high - inconel can take the temperature, but the regular structure underneath will melt

[@tipimaker]

Excellent video. So why is the radiation only emitted outwards away from the vessel. Shouldn't it be emitted in all directions from the tile, including into the ship?

[@spaceflightexplained360]

They do, but the radiation in does not get far due to how the tiles are made. For way more detail from an expert viewer, please look at the pinned comment :)

[@TiberiusMaximus]

nice job, I'm currently working on an animated SpaceX and space in general comedy shorts. I think its needed for us nerds to have a laugh now and then about our passion for space

[@spaceflightexplained360]

I think often the best comedy is straight out of Elon's twitter. Elon: "We are going to catch the booster with the tower" Me: "Haha, that is funny!!!"... "Wait, for are serious?"

[@TiberiusMaximus]

@@spaceflightexplained360 I know right, hopefully it will be that easy but Boeing makes it easy too that why they are in the 1st video

[@andytroo]

you should have circled back to the original number; if the tiles have a radiate:transfer ratio of 1:180, you could work out what fraction of the TJ of energy can be safely absorbed (and more than that, the back half of starship could be used as a radiator at a couple of hundred 'c safely to further vent the transmitted energy; 64,000 / 180 is only 355; the steel structure could just tank that without any further cooling...

[@thirteenthandy]

Is the tile 90 percent air, or 90 percent empty space? If air (or the gasses that make up air) is a critical part of it, how would it still work after being in space? Wouldn't it outgas and have only solid material by the time of re-entry?

[@spaceflightexplained360]

That is a great question, all the resources day that it is really trapped air and outgassing is not mentioned. That is an interesting detail that I should have doesn't spent more time on

[@ifyoubuildit6077]

This was great explanation. One thing that I felt was missing: If this welded stud type mechanical connection is that much better, why didn't the shuttle use it? Also, it would be nice to know why SpaceX used pica-X on the Dragon, but not on the Starship.

[@spaceflightexplained360]

Thank you for watching the video! As mentioned here, PICA(X) is ablative, so you have to rebuild it often or every time. Not good for rapid reusability. Why they didn't use a different method for attaching the Space shuttle tiles? Frankly, I don't know. Possibly the fact that they would have to be attached to the aluminum frame, which would be very tricky (disimilar metal corrosion and other stuff) and maybe weight constraints?

[@wim0104]

aren't the "expansion" gaps in between the tiles, to accommodate for the shrinking of the steel during orbit?

[@spaceflightexplained360]

Possibly! Or contractions when fueled? I'm not sure which thermal event is it aimed towards.

[@wim0104]

@@spaceflightexplained360 yes, very good, the cryo-fueling is probably the critical design parameter for those gaps.

[@JustRandomPerson]

In the last calculation Isn’t heat radiated in both direction?

[@spaceflightexplained360]

It is, but wouldn't it be reabsorbed right away by the tile? Only one side is the of the tile is hot and coated

[@JustRandomPerson]

@@spaceflightexplained360 I’ve just read pinned comment, I guess it explains it, internal part effectively reflects heat back to the coated layer.

[@jase4647]

Hey, where did you get your rockets? They're so cool! I'd like to get some.

[@spaceflightexplained360]

I wish I had them, but the whole background is a render that I made...

[@pmj_studio4065]

I'm curious how much of that heat would be transferred to the propellant. During reentry it's mostly gaseous methane/oxygen for pressurization, so it doesn't have as much heat capacity as the liquid form, but it is already gaseous, so there's no problem with boiling off. It could heat up, taking energy away form the steel, and be vented away if the pressure is too high. I wonder how much of an impact would it have.

[@spaceflightexplained360]

That is a really good question - In one way or another, they will be releasing the gas to keep the pressure at the intended levels, and it might take some heat with it. How much would it be? I think the question that will drive this is "How hot can the steel body get before things go bad". Because the fuel will not get hotter than that.

[@pmj_studio4065]

@@spaceflightexplained360 I don't think propellant will get hotter than the steel... unless it heats up due to increasing pressure? It's initially much colder, so heat is transferred from outside to the propellant.

[@spaceflightexplained360]

@@pmj_studio4065 Of course, my apologies, I somehow skipped the "not" there

[@pmj_studio4065]

@@spaceflightexplained360 ah, ok 😆

[@peeftribos]

So how many flights they can achieve without changing the tiles?

[@spaceflightexplained360]

That is the billion dollar question what they will try to answer. It is the mechanical wear and tear that will reduce the reuse...

[@ckdigitaltheqof6th210]

Most never understood the safety issues both the Space Shuttle had, or what "Starship" SN will deal with heat shield issues, BOTH needed full body coating of the HS tiles, any imbalance position re-entry , will be devistating. This will only need adjustnents of painting the area not entended to burn, if windows, will need a moon roof" style. For the Falcon 9, it used atmosphere, from its own rocket flares, SpaceX doesn't want to waste fuel for this safety, even for that misosphere, other alternatives would be a gel, to be subsitatude burn, or a seperate shield board.

[@ricardoabh3242]

About the blunt shape, wondering if there is an optimal curve? Circular, hyperbolic, square lol ?

[@spaceflightexplained360]

Don't quote me on that, but purely from pushing the shockwave away, I would say flat bottom. But, that is also aerodynamically unstable so not usable.

[@cabanford]

Elon has said that they made the "rocket more pointy" than optimal, as a nod to the movie The Dictator. Fits well with his Joe Rogan weed cloud piccy on your wall 😜

[@martianmanhunter3978]

Great vid, great channel. But I thought Elon Musk has said the tiles for Starship are made of ceramic material.

[@spaceflightexplained360]

It is! So is the Shuttle

[@slimessiful]

Nice intro

[@spaceflightexplained360]

:)

[@montfrypan5904]

i think, because i have the experience in my work in thermal furnaces processes , the combination of steel and liquid cooling are super efective. in long term this can be the best solution, for sure. flow his liquid metane in the skin, and vent the pressure, cooling the methane in a fast closed circuit, obviously talk is cheap, i pressume the reentry is only 3-5 minutes of hot pick, if the quantity of metane can ficht this period, i don't know why don't take this line.

[@spaceflightexplained360]

They seem to try it first without it for some reason. I'm sure that adding tiny channels into the mass produced steel is not trivial or cheap

[@trentconley4374]

Great video! Perhaps a conclusion at the end of your videos would be helpful to the average viewer like me who is interest in spaceflight but it is not the occupation (I'm a junior in high school). A conclusion, at least for me, would serve to explain how all of the concepts we just learned could be implemented. For example, you could give your thoughts on how SpaceX could use the Space Shuttle tiles, if ablative or heat sink tiles would work given projected decent times, and if either solution would allow Starship to be rapidly reusable. Keep up the great content though, I just subscribed and am excited to see more of your content! On an unrelated note, if you are a Brave verified content creator, I can tip you a cryptocurrency called BAT which would result in around a dollar per month from my end. It's not much from one user, but it can definitely add up fast as more people start using Brave as a browser.

[@spaceflightexplained360]

Hi Trent! Thank you for the support and suggestions! I generally do conclusions in my other videos, but here I kind of messed up be putting the math at the end...

[@alisioardiona727]

Very interesting video ! I thought starship would go for an ablative heatshield

[@steveaustin2686]

Then you would have to reapply a new ablative heatshield after every flight. Elon would like to get the Starship turnaround down to hours, but just getting down to days would be a big deal. IIRC, some recent Falcon 9 B5 boosters have been turned around in less than 4 weeks.

[@alisioardiona727]

@@steveaustin2686 you could have an ablative heat sheild that support multiple flight, then an automated way to replace it.

[@steveaustin2686]

@@alisioardiona727 I'm not sure that would work that well. If you have enough ablative material to survive multiple landings, then the first few landings are carrying extra weigh they don't need. As I understand it, the steel that Starship uses has over twice the heat capacity of the aluminum the Shuttle used. The heat capacity of the steel covers most of the range of heat values Starship should see. Adding tiles on top of that, and that should take care of it all. Not to mention, since Starship is on top of the booster, instead of side mounted like the Shuttle, you don't have to worry as much about tile damage from falling ice and insulation. Starship is not as complicated an airfoil as the Shuttle, so there are fewer unique tiles. I understand that almost all the Shuttle tiles were unique, greatly increasing the cost. Looks like the majority of Starship can be covered with the same hexagonal tiles, greatly increasing the turn around time if a tile is damaged.

[@spaceflightexplained360]

What the above commenters said. Not even Space Shuttle had ablative, and it was never supposed to fly as often as Starship.

[@sivakrishnat5471]

Seems SpaceX learned a lot from NASA's mistakes.

[@RahulKumar-ve4jm]

Life is to short to learn from mistake , so learn from other mistakes -Chanakya ( probably lol)

[@tgw230]

I thought the black color absorbs more heat than the white color, why are the tiles black? The tiles are all about minimizing heat absorption…

[@john8451]

Excellent presentation spoiled by so many ads! 😡

[@spaceflightexplained360]

Oh shoot, thank you for posting this! I didn't realize that the mid-video ads are on. It should be only in the beginning now

[@pvito8570]

So the Soyuz re-entry capsule, with spherical shape, from the 60s, was a better choice than the Apollo's conical shape.

[@spaceflightexplained360]

I am not sure about that. The sphere is simpler, more predictable, and requires less advanced control systems. But I think the blunt body cone has better performance. There is a reason why the commercial Spacecraft, especially reusable ones, have this shape.

[@darrengillesdarrengilles8336]

Considering such a large portion of starships surface is symmetrical why not fabricate the heat shielding in massive precast panels where the shape allows for it? Saves time and money and reduces the chances of shielding failure exponentially.

[@spaceflightexplained360]

I think the thermal expansion of underlying steel would fracture larger pieces in unpredictable way

[@brandoYT]

You show K and then say C. ??? and then add F - color me confused. You? info on heat shields - very interesting - well done.

[@spaceflightexplained360]

Yeah, temperatures are hard :-( I tried to be US friendly, and than it is sometimes better to use Kelvins (math) or Celsius for common things....

[@f.w.1318]

You would think the space shuttle interior frame structure would of been built on a titanium, or at least with of at titanium alloy with A-286 steel, such as the x-15, unfortunately I wasn't born yet but my father worked for a supplier that worked with these materials back in the 50s and 60s their biggest customer at the time was the US govt. any how A-286 maintains its corrosion resistance in temperatures up to 815 C when applied as an alloy with inconel metals, you can get a variety of combinations that each with distinct features and performance that will out preform aluminum, in strength and weight, and are welded using gas tungsten arc welding or electron-beam welding. The orbiter cost was astronomical, not only was the there the protective tile issue, but anytime the orbiter lost a tile the underneath aluminum structure had to be ultra sound tested, for any deficiencies in the material in regards to heat transfer, this process literally required a strip down on the orbiter. Space X saw the space shuttle program as what not to do, for reentry and how it could minimize cost and reusability, however most space x renders shows starship reentry as almost upright, where you show it more at an angle. I wonder with its cylinder shape would the stress on starship be equally displaced depending of the attack angle, or due to high velocity that would cancel out and place most of the stress on the fins, by the way great content, thank you

[@spaceflightexplained360]

Thank you for the great comment! Do you have a guess why they decided for aluminum at the end for the Orbiter? It is now an old information (2019), but Elon did mention that the angle of attack to be 60 degrees during the reentry.

[@njm3211]

@@spaceflightexplained360 My guess is weight.

[@cameronh3260]

I understood some of those words

[@spaceflightexplained360]

That is why I spend time making subtitles as well :)

[@angadsingh9314]

Hey do you have a Twitter account I have follow?

[@spaceflightexplained360]

No, I'm not really active that way. What information would you look for if I had one?

[@kenkremer2581]

There weren't tiles on the nose or leading edge. It was RCC!

[@spaceflightexplained360]

Ken, I believe that when I say it I am talking about RCC?

[@MichaNiki-xw2mq]

Well done video, I liked and subscribed. But big YouTub subtitle goes in some of Your video sequences bad over Your content. Starting at minute 16:00

[@spaceflightexplained360]

Thank you, I'll look at it!

[@noahandrews628]

You should consider reaching out to Nebula. Your in-depth content would be a great fit, your channel's existence would be known by a high percentage of Nebula subscribers, and you get a lot more money per view than you get on KZbin. And of course I'd get to watch your videos without ads :)

[@spaceflightexplained360]

Interesting thought! I think that my channel is too small to attract decent attention to it on Nebula, and has a very specific niche - I just do it for space nerds like me and I don't know how many would go to Nebula.

[@noahandrews628]

That's the cool thing about Nebula though, there's a small enough number of channels that people can browse through literally all of them, particular if you're just looking for channels in certain categories.

[@philbarker7477]

Spacex is using a version of TUFROC as used in the x-37.Developed by nasa.

[@spaceflightexplained360]

Do you have a source on that? Because I heard both "opinions" (SS tile & Tufroc). That is why I sort of made the video "even if they used the SS tile chemistry"

[@theOrionsarms]

Imitate the space shuttle solution for heatshild is a bad idea, if you consider only the fact that starship have a cylindrical shape that means that surface covered in tiles most be more than 55% bigger than for a flat belly, that means 800 square meters covered with tiles if it weights is only 20 kg/square meters that is more than 16 tonnes, a round shield put on one of the end caps will be lighter and make the same job and the starship wouldn't glide like space shuttle so could re-enter in the vertical position and not on the side also a instabily issue for a barrel shape vehicle.

[@spaceflightexplained360]

I think you are in the right ballpark, but those are the tradeoffs. The flat belly is not an option because the whole thing is a pressurized tanks and the added strength needed to sustain flat shape would be immense. Reentering in the vertical position can potentially make it worse, because the drag would be low and that means that you would hit the dense layer of atmosphere too fast, and burn up there. Not mentioning the G forces on the crew when the vehicle would reach 10-30 km altitude. Going belly first allows you to slow down gradually, using a little bit of lift to stay up longer and to have much smaller velocity lower down.

[@theOrionsarms]

@@spaceflightexplained360 for the hottest part of aerobreacking maneuver 11th meter diameter heatshild is enough, after that you can flip in the horizontal position, or if you change the design use larger gridfins (I mean much larger than in the booster) it's a tradeoff lighter heatshild but bigger and heavier aerodynamic surface controls and more stable re-entering. (also much cheaper and simpler doe to smaller and simpler shape round heatshield ).

[@wim0104]

With their big re-useable engines, why can't SpaceX slow the rocket down in orbit, and then drop like a stone? Why do they need to hot-surf the atmosphere to bleed of orbit velocity?

[@spaceflightexplained360]

@@wim0104 That woulds require them to carry more fuel for landing to slow down first, which would be directly subtracted from the payload capacity. It is a lot of fuel. I think they will still need to slow down a bit propulsively, just not all the way. Only as little as they can get away with.

[@theOrionsarms]

@@wim0104 propulsive landing isn't a option, but you can use smaller heatshield like I explained.

[@Ramash440]

6:04 - Ah, yes, the Ablative Head Shield. It refers to when you use your facial skin as an ablation material, thus charring everything but your skull.

[@spaceflightexplained360]

😂

[@erepsekahs]

One day someone will build a spaceship modelled on the look of Starship Enterprise. It would have to be built in space, but would be recognized by at least half the human race as a wonderful thing to do. Now THAT would an achievement. Maybe the descendant's of Gene Rodenberry, William Shatner, Leonard Nimoy and crew could encourage it.

[@spaceflightexplained360]

One day... Assembly of pressure vessels in space is exactly what a company I started few months ago is doing :)

[@MichaelGreenLagos]

What if the space craft rolled round spreading the heat

[@spaceflightexplained360]

I guess then half of the protection would be needed on twice the area?

[@MichaelGreenLagos]

@@spaceflightexplained360 so are you saying it would work

[@MichaelGreenLagos]

@@spaceflightexplained360 and also the speed of the roll would make a difference

[@spaceflightexplained360]

:) Do a barrel roll! I'm not sure how will the angle of attack can be held if the vehicle is spinning

[@spaceflightexplained360]

And there are also other things, like the need to protect from shockwaves on multiple directions if the vehicle has wings or fins

[@theresjer]

Napkin math is the best.

[@spaceflightexplained360]

Quick and dirty :)

[@ReachOutToWilliam]

I thought the Musk solution was to bleed rocket fuel through the craft skin. What is this talk of tiles? These things are going to pop off both at liftoff and reentry due to pure physical force, as well as due to the expansion of the steel skin (which is considerable) which will weaken the bond of the tiles to the fuselage. Steel, with welded mounting "studs" is brittle. My prediction? The starship is not suitable for reentry without considerable (and possibly fatal) results.

[@spaceflightexplained360]

That "sweating" was dropped a long long time ago.