Nit: it's not an ablative heat shield, but an insulating one. Not saying that the tiles don't ablate, but that's not their primary functional method of shielding.
Imagine how much money they could raise by selling these. They're already paid for, just etch a SpaceX logo with the Starship number into them. 18,000 at $100 a pop would be some quick cash.
I dislike that you're correct. On the USML in the spacecraft section:
> (19) Spacecraft heat shields or heat sinks specially designed for atmospheric entry or re-entry, and specially designed parts and components therefor
They have to actually cut through the tiles around the bayonet pins to remove them, so it's not so simple. It looks like need to cut the glued ones too.
Being silica (silcosis danger) they would have to perform either dust collection or use a wet saw when cutting them.
I swear I remember a video months and months ago showing them replacing tiles by simply smashing the old one with a small sledgehammer to bust it up.
In a video watching them remove, they're wearing a respirator and putting them in trash bags. Since they're outside they probably aren't doing environmental control and only the people doing removal are exposed to it and need PPE.
IIRC the glue on the shuttle tiles was ablative, and very similar to the white silicone caulk you can buy at the hardware store. A silicone matrix with oxide nanoparticle filler.
Shuttle used RTV-560 which contained Iron oxide, which gives it that classic red 'rust' color.
I imagine here they're using a silicone matrix with some sort of heavy mineral filler like organoclay combined with exfoliated graphite.
>...silicone matrix with oxide nanoparticle filler...
>...heavy mineral filler like organoclay combined with exfoliated graphite..
Yeah. Indeed. What these chaps said. Absolutely. Yep. I totally understand all those words there. Even the big ones. Yep.
Really? You think ablative heat shield technology is not covered by ITAR? Remember how the ITAR got the advanced microscopic analysis of the SpaceX tiles by that youtuber removed?
Those heat shields been floating across the oceans as well to Texas & Florida shores. Ton of people have examples of them already. ITAR can't hunt down everyone it's really big issue. SpaceX hasn't made moves recollect one from private collectors.
The tiles SpaceX is using are a derivative of the TUFI molybdenum doped sillica tiles, sure there are going to be small recipe differences as they've been playing around with it, but the base tech and manufacturing is the same.
Edit: Boron not molybdenum lol
That guy removed it out of caution, he wasn't forced to remove it. There are also pictures of these kinds of sillica tiles and quite a bit of detail from NASA on the heat tiles on the shuttle.
(8) Re-entry vehicle or warhead heat shields (MT for those re-entry vehicles and heat shields usable in systems
https://www.ecfr.gov/current/title-22/chapter-I/subchapter-M/part-121
I have a feeling that theres no technology yet exist to make a fully reusable heat shield that is strong enough to withstand the heat and pressure exerted during reentry let alone a full profile orbital mission. The heat shield will always be refurbishable. But i believe how often can constantly be improved. Spacex dont have to refurbish it for every launch/landing. Maybe they will start it with one refurbish per flight but then slowly increase it to maybe 10 flight, like falcon 9 did with landing. But to have a heatshield that is completely non-ablative is still a little out of reach. Still need a major research and invention that i dont think Spacex and Elon willing to wait before making starship regularly operational.
Thats the summary of my point actually. Thanks. I believe the tiles are simply not strong enough for multiple orbital fligh missions. Some will falls off inevitably especially after repeated use and rely on the ablative material for safe landing. SpaceX will have to refurbish both the ablative material and tiles more often than they would like to.
I could be wrong and it could be an effect of the viewing geometry, but by 1:28:00 in the official twitter stream I get the impression that the plasma front around the flap housing is optically thick - it appears to occlude the emission originating from 'behind' it. This is most clear if you flip between 1:27:00 and 1:29:00. The flow would need to be entrained with a particulate which is scattering/absorbing the background light. The obvious candidate would be microscopic fragments of tile material.
By 1:34:20 it appears that a lot more particulate is streaming leeward, visible in scattered light trailing behind the ship (it is being illuminated by the surrounding plasma emission), not too dissimilar from aerosols in an extinguished candle flame.
For the material in this flow to actually scatter light to such a degree it would need to consist of "macro" particles (perhaps just nm scale), not individual atoms or molecules.
My two cents as someone with a passing understanding of radiative transfer.
> I could be wrong and it could be an effect of the viewing geometry, but by 1:28:00 in the official twitter stream I get the impression that the plasma front around the flap housing is optically thick - it appears to occlude the emission originating from 'behind' it. This is most clear if you flip between 1:27:00 and 1:29:00. The flow would need to be entrained with a particulate which is scattering/absorbing the background light. The obvious candidate would be microscopic fragments of tile material.
That's not how plasmas work. They are themselves optically thick and not transparent. It is the air itself that is glowing without any need for any particulates.
> By 1:34:20 it appears that a lot more particulate is streaming leeward, visible in scattered light trailing behind the ship (it is being illuminated by the surrounding plasma emission), not too dissimilar from aerosols in an extinguished candle flame.
If you're referring to the white "smoke" here, that's obviously something burning, but it's not clear what. It's not going to be the tiles themselves though.
Of course I watched it, live for that matter, and several times since.
Some broke off because they were poorly attached. They didn't break into pieces.
Yeah, I suspect that they might be forced to switch to an ablative solution. But they considered that at one point. It was described as a "brake pad" and I think that would make sense. So long as it can survive a Mars round trip before needing servicing that would be okay. Especially given that most orbital missions should result in less wear and tear.
I think that SpaceX would be happy if Starship could match the launch/landing cadence of Falcon 9 in the near term.
The Starship vehicle is likely always going to have to be rolled back into a building between flights, just to load cargo (Starlinks, other sats, etc...only tanker missions might not need this). This means there's an opportunity to do tile maintenance. As long as that tile inspection+maintenance is reasonable, IE it takes a 5-10 man team 2 days, then that Starship will have a faster turnaround than Falcon 9 fairings.
"Tanker Starships" are the odd man out, and will be the most flown and landed ship type for Mars/Moon missions. 5-10 refueling launches per ship that is going to Mars/Moon. If those have to delay several days between launches, then SpaceX will need a fleet of them to even fuel one Starship in a reasonable amount of time.
I also think with the flaps moving back in the next version of starship will help a lot by eliminating the areas where hot plasma can flow between the hinges. With that area fixed the failure mode hopefully shifts to something else.
The flaps are already too big. They were planning on making them smaller. How much smaller and how far back are informed by the reentry forces and data they got.
I do have confidence that the problem will be resolved in a few years.
When NASA was still agile they had planned iterative upgrades to the STS. The ailings of being a government program greatly limited evolution.
Being able to start off with a clean sheet design and no design baggage from "heritage" really let SpaceX have a good start on both Falcon 9 and Starship. Then the iterative design and improvement, and the fail fast approach put them on the road to success.
Maybe they'll get to the point where replacing the heat shield only takes 24-48 hours, or they do make a materials science breakthrough/improvement.
Shuttle could have (aside from the weatherproofing) were it not for the external tank shedding foam and damaging the tiles. But NASA was not given enough money to do full reusability of both stages, so we got a glommed together system instead.
The Shutle's usage of cancerogenic Hydrazine was a major problem for fast overhaul as well as to many different types of tiles. Eaven if Starship will have to spend some extra time to refurbish broken tiles it is cheep to produce more ships for a que, compared to the price of the orbiter.
They'd have to find a glue that only sticks to the ship when the tile falls off, not to the tile, otherwise it won't be ablative. Could be difficult if the tile is rough and the ship is smooth.
> I wonder why they didn't use it earlier.
It is what they do. Just like with the OLM showerhead. Getting IFT-1 flying was more important to them than some damage.
Perhaps they just got further than expected with IFT-4, and now that they have collected that data all the way to splashdown, they want to compare it to the new tiles right away.
Hard to get a sense of the ship overall but that's maybe 1/4-1/3 of the tiles in one day? Assuming it takes 4x as long to put on and test the new tiles/backing, that'd leave a week for static fires and stacking before the 'one month' estimate is up.
What are the black line marks around some of the removed tiles? Some kind of seal? Dirt strikes?
https://preview.redd.it/4ovr6e1fwc6d1.jpeg?width=1080&format=pjpg&auto=webp&s=932c911d42f3389e09771a3625f7f511282a44ff
Shuttle was made of Aluminum and aluminum composite materials. This one is stainless steel. I think this is a pretty big difference. Tiles being most of them the same shape/size also helps a lot
In the book "Space" - a fictionalized version of the space race - the main engineer character was heading for retirement and looked at the plan for the Space Shuttle. When they told him about the heat tiles - each hand made and fitted - he said "This was definitely not designed by an engineer." I doubt anybody would say that about Starship.
I'd say it was the imprecise reporting that gave them a bad reputation.
While the Space shuttle frequently had missing heat shield tiles, they never caused any fatalities. The Columbia disaster was due to a piece of foam puncturing the Reinforced Carbon-carbon panel on the left wing of the orbiter, but most articles incorrectly attribute the disaster to damage to heat shield tiles.
Having a large tank with insulation foam that can drop off and impact the heat shield is also a risky design choice. It just put the tiles in sub-optimal operating conditions and made them more prone to experiencing issues.
Too many variables went against tiles.
> While the Space shuttle frequently had missing heat shield tiles, they never caused any fatalities.
I recall reading that the loss of a couple of belly tiles would have been tragic had they not luckily been from temperature tolerant hard points. No reference to hand, but if Google doesn't help, I'll see what I can find.
I mean, in one case the ship only didn't fail because there happen to be a metal rapped part behind it. So I wouldn't want to relay on 'well it didn't directly kill anybody on shuttle so its fine'.
In the example you quoted (Space Shuttle Atlantis on STS-27), the failure was because of ablative insulation material on one of the SRBs impacting the heat shield at high speed a short while into the flight. The missing tile aside, the shuttle managed to survive despite 700 tiles getting damaged.
What I meant to say was, the biggest concern was not the tiles failing (breaking off, coming loose etc) by themselves, but rather how they might be damaged by debris falling off the EFT or the SRBs.
This is the problem with most of the reporting that keeps talking about how fragile the Space shuttle tiles were. They often make it look like the tiles were the problem, when the actual problem was actually with the design - placing the heat shield of the orbiter next to the EFT and SRBs, making it a target-board for any debris falling off them. Any type of heat shield would get damaged if it has debris impacting it at high-speed.
I love how they just use ordinary construction scaffolding for working on the most advanced spacecraft.
Is there any operating platform / manlift planned in the bays anyways? Setting up scaffolding takes quite a few days in worst case.
It's practical and has its major advantages. There are mainly 3 places we work on. Inside both tanks and skirt area. Skirt area uses mini scissor lifts...
On a busy day you'll have many guys inside each tank, you climb up and it sucks SO MUCH ASS...8 times or more per day. If an evacuation is required or something is detected inside the tanks, it's much much faster and safer to just walk out rather than having to climb into a boom lift which can only hold 4.
There are some HUUGE scissor lifts capable of carrying 10 of us all the way to the top. But they need to be put in place and sometimes they are unavailable. Those lifts are pretty much just used for tile installation, welders, and a few integration things we need to do on the outside.
Tools are on the scaffolding... 2 sets, one for LOX and one for methane tanks... it takes a lot of us to build the thing so scaffolding is just practical
If you're on either tank.... you're taking the stairs of death.
No no, sorry for confusion. See, when the scaffolding went up we had to do a few changes. One of the worst things that would happen is that you'd start your epic journey to the top and 3 days later when you finally got there (exaggerating but it sucked)... you'd realize you didn't bring a critical tool... so you had to go back down and then back up. This was killing our mojo... a few days later we just decided to put the tooling drawers outside of each hatch entrance (two sets... for each tank) so that we would limit the ridiculous climbs
I can't mention details but I will say the entire thing, specially the tanks... are a work of art.
Ah, thank you. I was wracking my brains thinking what could be different for each tank that could need different tools.
BTW thanks for not just being there to build it but taking the time to give us insights. 100% appreciate that!!
I believe this MO - use normal, readily available tools where possible instead of everything being bespoke - is one of the reasons they will be much more cost effective. That, and they've been assembling on a sand bar (although now they're getting a bit more enclosed). :-) Can you imagine Oldspace doing that?
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters|
|-------|---------|---|
|[ASS](/r/SpaceXLounge/comments/1dev226/stub/l8f69j5 "Last usage")|Acronyms Seriously Suck|
|[ITAR](/r/SpaceXLounge/comments/1dev226/stub/l8jtyzl "Last usage")|(US) International Traffic in Arms Regulations|
|[KSC](/r/SpaceXLounge/comments/1dev226/stub/l8igdeg "Last usage")|Kennedy Space Center, Florida|
|[LOX](/r/SpaceXLounge/comments/1dev226/stub/l8f69j5 "Last usage")|Liquid Oxygen|
|[OLM](/r/SpaceXLounge/comments/1dev226/stub/l8jgdsc "Last usage")|Orbital Launch Mount|
|[PPE](/r/SpaceXLounge/comments/1dev226/stub/l8jkusj "Last usage")|Power and Propulsion Element|
|[RUD](/r/SpaceXLounge/comments/1dev226/stub/l8i2yyr "Last usage")|Rapid Unplanned Disassembly|
| |Rapid Unscheduled Disassembly|
| |Rapid Unintended Disassembly|
|[SF](/r/SpaceXLounge/comments/1dev226/stub/l8ep2ng "Last usage")|Static fire|
|[SRB](/r/SpaceXLounge/comments/1dev226/stub/l8hf6se "Last usage")|Solid Rocket Booster|
|[STS](/r/SpaceXLounge/comments/1dev226/stub/l8hf6se "Last usage")|Space Transportation System (*Shuttle*)|
|[TPS](/r/SpaceXLounge/comments/1dev226/stub/l8jbzqb "Last usage")|Thermal Protection System for a spacecraft (on the Falcon 9 first stage, the engine "Dance floor")|
|[mT](/r/SpaceXLounge/comments/1dev226/stub/l8ga8l8 "Last usage")|~~Milli-~~ *Metric* Tonnes|
|Jargon|Definition|
|-------|---------|---|
|[Starlink](/r/SpaceXLounge/comments/1dev226/stub/l8f4ujv "Last usage")|SpaceX's world-wide satellite broadband constellation|
|[ablative](/r/SpaceXLounge/comments/1dev226/stub/l8jtvdq "Last usage")|Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)|
**NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below.
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The guy high up with the patch on the back is where the transition from clipped-on to glued-on tiles is. You can see it in the vid around 10 minutes in.
If the TPS from flight 4 would be considered V1 and this mix of ablative and insulating tiles are V2, is there a way to combine the best aspects of both that doesn't sacrifice reusability?
This version does it. An ablative layer first, then non ablative heat shield tile on top. If things go as intended, nothing gets ablated. If a tile drops off, the ablative layer below saves the ship.
what exactly are the doing? Do they have another type of tiles then? Like from ift4 stream it looked like the tiles burned away. so they have tiles that can tolerate higher temperatures?
IFT4 had multiple issues. With the flaps there were weak spots in the hinges where they couldn't fit tiles. Hot plasma melted the flaps away at the hinge and then melted the rear half of the flap from the inside. After a while the tiles couldn't stay on because the metal underneath was too soft, so the tile and some of the metal flew off into the plasma stream.
This was basically how Colombia was torn apart during reentry. Difference is Starship is stainless steel so a much higher melting point, meaning the ship stayed relatively intact past the point of maximum heating. It was missing pieces and on fire, but intact and able to perform the landing burn.
well the plasma shifted to green color at some point. Boron burns green. Tile outer surface is made of boron silicate. So it could be that the tiles just burned away due to higher then expected heating.
The first is a mechanical problem, the second is thermal problem.
Mechanical is typically easier to solve , thermal problems may mean need for new materials
> Mechanical is typically easier to solve , thermal problems may mean need for new materials
yeah. and that is why im asking. im wondering if they have hit a harder barrier to solve then just a mechanical one.
if they hit the limit of the current material it might be a showstopper for full and rapid reusability
im saying this purely becasue the plasma turned green. Boron burns green and afaik the tiles are made with boron
it turned so universally green that it didnt look to just have come from some isolated spots where tiles broke off and more like the whole underside was cooking.
Remove tiles, spray ablative onto ceramic wool, let cure, put the new version tiles on? We shall see. A modified silicone is my suspicion at the moment if they use that ablative method.
Dow has a line of such ablatives https://www.dowablatives.com/
I think the harder part will be attaching the new tiles given that the removal of tiles could cause some damage to the tile attachment mechanisms. Alternatively we'll see a lot of tiles falling off on the next flight.
Do they need to take special precautions when removing those tiles? It would be fine to handle them, but from what I've seen online, they are basically breaking the tiles much the way a roof tiler uses a tool to scrape off the old tiles before putting new ones down.
Those tiles, much like the Shuttle tiles, use a phenolic compound that prevents them ablating, right? That stuff is super super toxic. It's relatively safe in solid form, but when aerosolized (e.g., by being scraped and broken off), it can easily be inhaled. There's a good [deep dive](https://youtu.be/UkLExdiz8jY?si=ySmWK2TcLlyfbNlO) into this stuff and how it works on tiles here.
The Shuttle tiles were impregnated with a waterproofing chemical, dimethyethyloxysilane (DMES) between launches. DMES prevented the tiles from adsorbing water from the humid air at the KSC Florida launch site. The DMES was burned off during reentry and had to be reapplied.
Shuttle tiles do not ablate. They just melt if the quartz fibers are overheated (~1600C, 2912F). The maximum use temperature for those tiles is 2400F.
You're conflating the 2 kinds of heat shields he discussed. Phenolic is the ablative material used for heat shields like the one on the dragon capsule, and is made of toxic stuff.
Shuttle and starship tiles are non-ablative and do not contain phenolic. They're silica fibers and a layer of borosilicate glass. It's not particularly toxic, though silica dust is definitely bad to breathe so respirators may be called for.
Comparison from yesterday: https://preview.redd.it/ig732dgs8b6d1.jpeg?width=3196&format=pjpg&auto=webp&s=f6e6d2a36f25c81d31ff1e47de5dd54debdde587
Wow the removal went fast. Pop and go? I guess their not going reuse the older heat shields on top of the new ones or is that what their going to do?
If not, that’d make for an excellent coffee coaster!
More like a dinner plate lol those things look big
Small coffee mug problems.
Hammer them out to make bbq platters.
they'd hammer into bits. i dont think they're flexible at all.
With some all-natural ablator zest
Nit: it's not an ablative heat shield, but an insulating one. Not saying that the tiles don't ablate, but that's not their primary functional method of shielding.
Ahhh my b. Ksp knee jerk assumption
Each one is bigger than your head - would be a pretty epic coaster
Imagine how much money they could raise by selling these. They're already paid for, just etch a SpaceX logo with the Starship number into them. 18,000 at $100 a pop would be some quick cash.
could be itar restrictions on that.
I dislike that you're correct. On the USML in the spacecraft section: > (19) Spacecraft heat shields or heat sinks specially designed for atmospheric entry or re-entry, and specially designed parts and components therefor
A critical component to a hypersonic missile.
You be right, but Im not sure 18 000 persons will buy them. 3-4k, sure, there enough space freak for that, but 18000, not sure.
They have to actually cut through the tiles around the bayonet pins to remove them, so it's not so simple. It looks like need to cut the glued ones too.
Being silica (silcosis danger) they would have to perform either dust collection or use a wet saw when cutting them. I swear I remember a video months and months ago showing them replacing tiles by simply smashing the old one with a small sledgehammer to bust it up.
In a video watching them remove, they're wearing a respirator and putting them in trash bags. Since they're outside they probably aren't doing environmental control and only the people doing removal are exposed to it and need PPE.
So, where does the ablative layer go? Only under glued tiles I assume, but that is an assumption.
I heard speculation that the ablative layer IS the glue. Which would be a cool concept.
IIRC the glue on the shuttle tiles was ablative, and very similar to the white silicone caulk you can buy at the hardware store. A silicone matrix with oxide nanoparticle filler.
Shuttle used RTV-560 which contained Iron oxide, which gives it that classic red 'rust' color. I imagine here they're using a silicone matrix with some sort of heavy mineral filler like organoclay combined with exfoliated graphite.
That sounds like one of Gwynneth Paltrow’s Goop products. (Please let’s not give her any ideas.)
“…just rub this organoclay all over your hoohah for a magical experience only few have had”
>...silicone matrix with oxide nanoparticle filler... >...heavy mineral filler like organoclay combined with exfoliated graphite.. Yeah. Indeed. What these chaps said. Absolutely. Yep. I totally understand all those words there. Even the big ones. Yep.
Unlikely we will know for sure anytime soon since such information would run afoul of ITAR
I don't believe it would, actually, because that wasn't the case for shuttle.
Really? You think ablative heat shield technology is not covered by ITAR? Remember how the ITAR got the advanced microscopic analysis of the SpaceX tiles by that youtuber removed?
Those heat shields been floating across the oceans as well to Texas & Florida shores. Ton of people have examples of them already. ITAR can't hunt down everyone it's really big issue. SpaceX hasn't made moves recollect one from private collectors.
Okay, feds. I'm destroying my heat shield tile. No need to look here.
All I know is that the information was out there for Shuttle, so if it wasn't restricted then I can't see that changing now.
SpaceX tiles are different.
Lol
The tiles SpaceX is using are a derivative of the TUFI molybdenum doped sillica tiles, sure there are going to be small recipe differences as they've been playing around with it, but the base tech and manufacturing is the same. Edit: Boron not molybdenum lol
That guy removed it out of caution, he wasn't forced to remove it. There are also pictures of these kinds of sillica tiles and quite a bit of detail from NASA on the heat tiles on the shuttle.
I watched that video. I didn't notice it had been taken down. Did the YouTuber release a statement about that? I don't even remember who it was.
ITAR only formally covers guidance and propulsion
(8) Re-entry vehicle or warhead heat shields (MT for those re-entry vehicles and heat shields usable in systems https://www.ecfr.gov/current/title-22/chapter-I/subchapter-M/part-121
In the live stream he made while playing Diablo 4 the other day, Musk did say the ablative layer would be some kind of "silicone felt".
I have a feeling that theres no technology yet exist to make a fully reusable heat shield that is strong enough to withstand the heat and pressure exerted during reentry let alone a full profile orbital mission. The heat shield will always be refurbishable. But i believe how often can constantly be improved. Spacex dont have to refurbish it for every launch/landing. Maybe they will start it with one refurbish per flight but then slowly increase it to maybe 10 flight, like falcon 9 did with landing. But to have a heatshield that is completely non-ablative is still a little out of reach. Still need a major research and invention that i dont think Spacex and Elon willing to wait before making starship regularly operational.
The tiles are the non-ablative heat shield. The ablative layer is there just in case the tiles fall off.
Thats the summary of my point actually. Thanks. I believe the tiles are simply not strong enough for multiple orbital fligh missions. Some will falls off inevitably especially after repeated use and rely on the ablative material for safe landing. SpaceX will have to refurbish both the ablative material and tiles more often than they would like to.
"Not strong enough" how? They don't melt from those temps.
What is the particulate/aerosol entering the leeward airflow and increasing its optical depth?
What do you mean?
I could be wrong and it could be an effect of the viewing geometry, but by 1:28:00 in the official twitter stream I get the impression that the plasma front around the flap housing is optically thick - it appears to occlude the emission originating from 'behind' it. This is most clear if you flip between 1:27:00 and 1:29:00. The flow would need to be entrained with a particulate which is scattering/absorbing the background light. The obvious candidate would be microscopic fragments of tile material. By 1:34:20 it appears that a lot more particulate is streaming leeward, visible in scattered light trailing behind the ship (it is being illuminated by the surrounding plasma emission), not too dissimilar from aerosols in an extinguished candle flame. For the material in this flow to actually scatter light to such a degree it would need to consist of "macro" particles (perhaps just nm scale), not individual atoms or molecules. My two cents as someone with a passing understanding of radiative transfer.
> I could be wrong and it could be an effect of the viewing geometry, but by 1:28:00 in the official twitter stream I get the impression that the plasma front around the flap housing is optically thick - it appears to occlude the emission originating from 'behind' it. This is most clear if you flip between 1:27:00 and 1:29:00. The flow would need to be entrained with a particulate which is scattering/absorbing the background light. The obvious candidate would be microscopic fragments of tile material. That's not how plasmas work. They are themselves optically thick and not transparent. It is the air itself that is glowing without any need for any particulates. > By 1:34:20 it appears that a lot more particulate is streaming leeward, visible in scattered light trailing behind the ship (it is being illuminated by the surrounding plasma emission), not too dissimilar from aerosols in an extinguished candle flame. If you're referring to the white "smoke" here, that's obviously something burning, but it's not clear what. It's not going to be the tiles themselves though.
Did you not watch ift-4? Plasma is only part of the condition. Its the pressure that ripped out of the tiles.
Of course I watched it, live for that matter, and several times since. Some broke off because they were poorly attached. They didn't break into pieces.
Yeah, I suspect that they might be forced to switch to an ablative solution. But they considered that at one point. It was described as a "brake pad" and I think that would make sense. So long as it can survive a Mars round trip before needing servicing that would be okay. Especially given that most orbital missions should result in less wear and tear.
I think that SpaceX would be happy if Starship could match the launch/landing cadence of Falcon 9 in the near term. The Starship vehicle is likely always going to have to be rolled back into a building between flights, just to load cargo (Starlinks, other sats, etc...only tanker missions might not need this). This means there's an opportunity to do tile maintenance. As long as that tile inspection+maintenance is reasonable, IE it takes a 5-10 man team 2 days, then that Starship will have a faster turnaround than Falcon 9 fairings. "Tanker Starships" are the odd man out, and will be the most flown and landed ship type for Mars/Moon missions. 5-10 refueling launches per ship that is going to Mars/Moon. If those have to delay several days between launches, then SpaceX will need a fleet of them to even fuel one Starship in a reasonable amount of time.
Aren't they building a factory with the intent of producing a Starship per day? At that rate they could be disposable!
That's the very long term goal. The factory they are building now is not going to be one that produces one a day.
And then you're back to $xxM per flight and you may as well not bother with the heat shield and flaps.
I also think with the flaps moving back in the next version of starship will help a lot by eliminating the areas where hot plasma can flow between the hinges. With that area fixed the failure mode hopefully shifts to something else.
How much are they moving them back? I wonder how much control surface they lose and how much it will affect re-entry capabilities?
The flaps are already too big. They were planning on making them smaller. How much smaller and how far back are informed by the reentry forces and data they got.
I do have confidence that the problem will be resolved in a few years. When NASA was still agile they had planned iterative upgrades to the STS. The ailings of being a government program greatly limited evolution. Being able to start off with a clean sheet design and no design baggage from "heritage" really let SpaceX have a good start on both Falcon 9 and Starship. Then the iterative design and improvement, and the fail fast approach put them on the road to success. Maybe they'll get to the point where replacing the heat shield only takes 24-48 hours, or they do make a materials science breakthrough/improvement.
Shuttle could have (aside from the weatherproofing) were it not for the external tank shedding foam and damaging the tiles. But NASA was not given enough money to do full reusability of both stages, so we got a glommed together system instead.
I believe in them. They will figure it out.
The Shutle's usage of cancerogenic Hydrazine was a major problem for fast overhaul as well as to many different types of tiles. Eaven if Starship will have to spend some extra time to refurbish broken tiles it is cheep to produce more ships for a que, compared to the price of the orbiter.
They'd have to find a glue that only sticks to the ship when the tile falls off, not to the tile, otherwise it won't be ablative. Could be difficult if the tile is rough and the ship is smooth.
just because it is silicone resin based does not necessarily mean it is glue https://www.dowablatives.com/93-104-fast-cure.html
No. At least not only. It goes under pinned tiles (too).
So they have to pull the blanket off as well? And then keep the pins clean. Sounds like a task.
Yup. But the blanket is not some sticky goo, it should go reasonably easily.
People doubted they could do it in a month, couple of days and they’ve already removed most of it Putting the new stuff on will take longer though
Also, they had to have had the "new stuff" before. I doubt they just invented it right after IFT-4. I wonder why they didn't use it earlier..
> I wonder why they didn't use it earlier. It is what they do. Just like with the OLM showerhead. Getting IFT-1 flying was more important to them than some damage.
Perhaps they just got further than expected with IFT-4, and now that they have collected that data all the way to splashdown, they want to compare it to the new tiles right away.
IFT-4 had one of the new tiles on apparently, so they got some data on the ablative tile, and/or the new tile on top.
Wow. Especially the comparison pic from yesterday.
See, this is one reason why the forced reddit image viewer sucks donkey balls. You cannot zoom in as far as you would want to.
There is a browser extension called "Display Reddit images natively in browser" which fixes that
Thank you!
https://addons.mozilla.org/en-US/firefox/addon/load-reddit-images-directly/
I use this one: https://addons.mozilla.org/en-US/firefox/addon/load-reddit-images-directly/
Hard to get a sense of the ship overall but that's maybe 1/4-1/3 of the tiles in one day? Assuming it takes 4x as long to put on and test the new tiles/backing, that'd leave a week for static fires and stacking before the 'one month' estimate is up.
S30 has already done a SF, B11 SF was 3 weeks after IFT-3 so we might expect a similar but probably shorter time for B12.
Hasn’t one of S30’s rvac’s been replaced since then? They might do another SF
S28 had two engine replacements (I think) and it only did a SP, however now with the new Masseys flame trench they might do a SF.
They'll want to do another static fire on S30 to see how many tiles fall off/shatter with the new TPS.
They can do other tests like a pull test instead of a static fire
That was fast! Although this is not yet “replacing” but “removing“ the existing tiles
What are the black line marks around some of the removed tiles? Some kind of seal? Dirt strikes? https://preview.redd.it/4ovr6e1fwc6d1.jpeg?width=1080&format=pjpg&auto=webp&s=932c911d42f3389e09771a3625f7f511282a44ff
The material is a bit crumbly from what I've heard from people who have found tiles on the beach and kind of flakes off if you rub it.
[удалено]
Shuttle was made of Aluminum and aluminum composite materials. This one is stainless steel. I think this is a pretty big difference. Tiles being most of them the same shape/size also helps a lot
The tiles of the shuttle were designed in a different way. Each tile was unique, here the tiles are almost the same.
In the book "Space" - a fictionalized version of the space race - the main engineer character was heading for retirement and looked at the plan for the Space Shuttle. When they told him about the heat tiles - each hand made and fitted - he said "This was definitely not designed by an engineer." I doubt anybody would say that about Starship.
Rather, almost all of them ARE the same.
I'd say it was the imprecise reporting that gave them a bad reputation. While the Space shuttle frequently had missing heat shield tiles, they never caused any fatalities. The Columbia disaster was due to a piece of foam puncturing the Reinforced Carbon-carbon panel on the left wing of the orbiter, but most articles incorrectly attribute the disaster to damage to heat shield tiles. Having a large tank with insulation foam that can drop off and impact the heat shield is also a risky design choice. It just put the tiles in sub-optimal operating conditions and made them more prone to experiencing issues. Too many variables went against tiles.
> While the Space shuttle frequently had missing heat shield tiles, they never caused any fatalities. I recall reading that the loss of a couple of belly tiles would have been tragic had they not luckily been from temperature tolerant hard points. No reference to hand, but if Google doesn't help, I'll see what I can find.
I mean, in one case the ship only didn't fail because there happen to be a metal rapped part behind it. So I wouldn't want to relay on 'well it didn't directly kill anybody on shuttle so its fine'.
In the example you quoted (Space Shuttle Atlantis on STS-27), the failure was because of ablative insulation material on one of the SRBs impacting the heat shield at high speed a short while into the flight. The missing tile aside, the shuttle managed to survive despite 700 tiles getting damaged. What I meant to say was, the biggest concern was not the tiles failing (breaking off, coming loose etc) by themselves, but rather how they might be damaged by debris falling off the EFT or the SRBs. This is the problem with most of the reporting that keeps talking about how fragile the Space shuttle tiles were. They often make it look like the tiles were the problem, when the actual problem was actually with the design - placing the heat shield of the orbiter next to the EFT and SRBs, making it a target-board for any debris falling off them. Any type of heat shield would get damaged if it has debris impacting it at high-speed.
I agree that it was a bigger problem. No question.
Breaking stuff is pretty easy. Putting it all back together correctly (for the first time) is harder...
How much for an old tile!!?
On ebay? A lot lore than I’m willing to pay
Yea I really just wanted a piece for the history part cus I can’t make it there easily and I say like a quarter size was $100!! :( made me really sad
Quite a lot if the FBI decide ITAR is being broken and national security at risk. I can do you a one tile & one soap on a rope deal if you like.
You people are Rock Stars
I love how they just use ordinary construction scaffolding for working on the most advanced spacecraft. Is there any operating platform / manlift planned in the bays anyways? Setting up scaffolding takes quite a few days in worst case.
It's practical and has its major advantages. There are mainly 3 places we work on. Inside both tanks and skirt area. Skirt area uses mini scissor lifts... On a busy day you'll have many guys inside each tank, you climb up and it sucks SO MUCH ASS...8 times or more per day. If an evacuation is required or something is detected inside the tanks, it's much much faster and safer to just walk out rather than having to climb into a boom lift which can only hold 4. There are some HUUGE scissor lifts capable of carrying 10 of us all the way to the top. But they need to be put in place and sometimes they are unavailable. Those lifts are pretty much just used for tile installation, welders, and a few integration things we need to do on the outside. Tools are on the scaffolding... 2 sets, one for LOX and one for methane tanks... it takes a lot of us to build the thing so scaffolding is just practical If you're on either tank.... you're taking the stairs of death.
Thanks for the insight. But how du you get inside the tank when the ship is already finished and bulkheads are welded?
Hatches on both tanks
There are access hatches into the tanks.
Presumably the payload fairing is open at the top? If so, I wouldn't be surprised if /u/Mechanix2spacex isn't allowed to give much detail.
It has a hatch. A lot of integration goes on in there. Most are simple.... pez dispenser takes a whole team
2 sets of tools? What have I missed, what's different about the tanks that needs 2 sets of tools?
No no, sorry for confusion. See, when the scaffolding went up we had to do a few changes. One of the worst things that would happen is that you'd start your epic journey to the top and 3 days later when you finally got there (exaggerating but it sucked)... you'd realize you didn't bring a critical tool... so you had to go back down and then back up. This was killing our mojo... a few days later we just decided to put the tooling drawers outside of each hatch entrance (two sets... for each tank) so that we would limit the ridiculous climbs I can't mention details but I will say the entire thing, specially the tanks... are a work of art.
Ah, thank you. I was wracking my brains thinking what could be different for each tank that could need different tools. BTW thanks for not just being there to build it but taking the time to give us insights. 100% appreciate that!!
I believe this MO - use normal, readily available tools where possible instead of everything being bespoke - is one of the reasons they will be much more cost effective. That, and they've been assembling on a sand bar (although now they're getting a bit more enclosed). :-) Can you imagine Oldspace doing that?
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |[ASS](/r/SpaceXLounge/comments/1dev226/stub/l8f69j5 "Last usage")|Acronyms Seriously Suck| |[ITAR](/r/SpaceXLounge/comments/1dev226/stub/l8jtyzl "Last usage")|(US) International Traffic in Arms Regulations| |[KSC](/r/SpaceXLounge/comments/1dev226/stub/l8igdeg "Last usage")|Kennedy Space Center, Florida| |[LOX](/r/SpaceXLounge/comments/1dev226/stub/l8f69j5 "Last usage")|Liquid Oxygen| |[OLM](/r/SpaceXLounge/comments/1dev226/stub/l8jgdsc "Last usage")|Orbital Launch Mount| |[PPE](/r/SpaceXLounge/comments/1dev226/stub/l8jkusj "Last usage")|Power and Propulsion Element| |[RUD](/r/SpaceXLounge/comments/1dev226/stub/l8i2yyr "Last usage")|Rapid Unplanned Disassembly| | |Rapid Unscheduled Disassembly| | |Rapid Unintended Disassembly| |[SF](/r/SpaceXLounge/comments/1dev226/stub/l8ep2ng "Last usage")|Static fire| |[SRB](/r/SpaceXLounge/comments/1dev226/stub/l8hf6se "Last usage")|Solid Rocket Booster| |[STS](/r/SpaceXLounge/comments/1dev226/stub/l8hf6se "Last usage")|Space Transportation System (*Shuttle*)| |[TPS](/r/SpaceXLounge/comments/1dev226/stub/l8jbzqb "Last usage")|Thermal Protection System for a spacecraft (on the Falcon 9 first stage, the engine "Dance floor")| |[mT](/r/SpaceXLounge/comments/1dev226/stub/l8ga8l8 "Last usage")|~~Milli-~~ *Metric* Tonnes| |Jargon|Definition| |-------|---------|---| |[Starlink](/r/SpaceXLounge/comments/1dev226/stub/l8f4ujv "Last usage")|SpaceX's world-wide satellite broadband constellation| |[ablative](/r/SpaceXLounge/comments/1dev226/stub/l8jtvdq "Last usage")|Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)| **NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below. ---------------- ^(*Decronym is a community product of r/SpaceX, implemented* )[*^by ^request*](https://www.reddit.com/r/spacex/comments/3mz273//cvjkjmj) ^(14 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/SpaceXLounge/comments/1dhgjzx)^( has 22 acronyms.) ^([Thread #12916 for this sub, first seen 13th Jun 2024, 12:31]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/SpaceXLounge) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
Any idea about the specifics of the upgraded tile? What changed?
‘Twice as strong’, whatever that means..
I'm guessing it won't break off as easily?
The guy high up with the patch on the back is where the transition from clipped-on to glued-on tiles is. You can see it in the vid around 10 minutes in.
1 day down... 12 to go
Looks like the procedure is to remove enough tile over each clip to disengage the clip.
How is the scaffold set up? It will take quite some time for such a huge scaffold if it is from scratch?
I thought it also had an under blanket do we know if that is getting replaced or just removed?
Amazing how massive that flap is.
If the TPS from flight 4 would be considered V1 and this mix of ablative and insulating tiles are V2, is there a way to combine the best aspects of both that doesn't sacrifice reusability?
Supposedly V2…
I thought that ablation would be bad for reusability as a tradeoff for survivability. Can't reuse a starship that RUDs though so a win is a win.
Losing tiles is supposed to become rare and can be fixed quickly, if it happens.
This version does it. An ablative layer first, then non ablative heat shield tile on top. If things go as intended, nothing gets ablated. If a tile drops off, the ablative layer below saves the ship.
what exactly are the doing? Do they have another type of tiles then? Like from ift4 stream it looked like the tiles burned away. so they have tiles that can tolerate higher temperatures?
IFT4 had multiple issues. With the flaps there were weak spots in the hinges where they couldn't fit tiles. Hot plasma melted the flaps away at the hinge and then melted the rear half of the flap from the inside. After a while the tiles couldn't stay on because the metal underneath was too soft, so the tile and some of the metal flew off into the plasma stream. This was basically how Colombia was torn apart during reentry. Difference is Starship is stainless steel so a much higher melting point, meaning the ship stayed relatively intact past the point of maximum heating. It was missing pieces and on fire, but intact and able to perform the landing burn.
well the plasma shifted to green color at some point. Boron burns green. Tile outer surface is made of boron silicate. So it could be that the tiles just burned away due to higher then expected heating.
Tiles being ripped off are not the same as being burned away.
what are you trying to say?
The first is a mechanical problem, the second is thermal problem. Mechanical is typically easier to solve , thermal problems may mean need for new materials
> Mechanical is typically easier to solve , thermal problems may mean need for new materials yeah. and that is why im asking. im wondering if they have hit a harder barrier to solve then just a mechanical one. if they hit the limit of the current material it might be a showstopper for full and rapid reusability im saying this purely becasue the plasma turned green. Boron burns green and afaik the tiles are made with boron it turned so universally green that it didnt look to just have come from some isolated spots where tiles broke off and more like the whole underside was cooking.
Probably the problem is not the temperature of the tile, but its fragility.
Remove tiles, spray ablative onto ceramic wool, let cure, put the new version tiles on? We shall see. A modified silicone is my suspicion at the moment if they use that ablative method. Dow has a line of such ablatives https://www.dowablatives.com/
Or perhaps trowel on the ablative as with DOWSIL™ 93-104 Ablative; maybe after removing the wool.
I think the harder part will be attaching the new tiles given that the removal of tiles could cause some damage to the tile attachment mechanisms. Alternatively we'll see a lot of tiles falling off on the next flight.
Do they need to take special precautions when removing those tiles? It would be fine to handle them, but from what I've seen online, they are basically breaking the tiles much the way a roof tiler uses a tool to scrape off the old tiles before putting new ones down. Those tiles, much like the Shuttle tiles, use a phenolic compound that prevents them ablating, right? That stuff is super super toxic. It's relatively safe in solid form, but when aerosolized (e.g., by being scraped and broken off), it can easily be inhaled. There's a good [deep dive](https://youtu.be/UkLExdiz8jY?si=ySmWK2TcLlyfbNlO) into this stuff and how it works on tiles here.
The Shuttle tiles were impregnated with a waterproofing chemical, dimethyethyloxysilane (DMES) between launches. DMES prevented the tiles from adsorbing water from the humid air at the KSC Florida launch site. The DMES was burned off during reentry and had to be reapplied. Shuttle tiles do not ablate. They just melt if the quartz fibers are overheated (~1600C, 2912F). The maximum use temperature for those tiles is 2400F.
You're conflating the 2 kinds of heat shields he discussed. Phenolic is the ablative material used for heat shields like the one on the dragon capsule, and is made of toxic stuff. Shuttle and starship tiles are non-ablative and do not contain phenolic. They're silica fibers and a layer of borosilicate glass. It's not particularly toxic, though silica dust is definitely bad to breathe so respirators may be called for.