Starship heat shield

[rsdavis9]

Thunderf00t videos are not worth engaging with.

Well I did say it was a "very negative". I was only interested in the waterproofing part. Oxygen atoms on the outside of SiO2 bonds with water which makes it hydrophilic. So bonding a methyl group to the oxygen makes it hydrophobic. bonding here meaning weak hydrogen bonding. So I was just trying to understand if there was a chemical that doesn't "boil off" under heat.

It looks like SiC is water loving. Sort of like CaC that we as kids used to make are canons go boom.
So what is dream chaser using to protect their SiC heat tiles?

from google ai:

The Dream Chaser heat shield uses a new thermal protection system (TPS) of approximately 2,000 larger, composite tiles made of a proprietary mix of silicon carbide and carbon fiber to withstand extreme re-entry temperatures.

[SpaceManJoe]

It rains all the time in Florida, and it will randomly rain, this was a huge problem for the space shuttle tiles, it would just randomly rain in Florida and those tiles would soak up water.

There was a thread about this on X I read a while back, the guy said the space shuttle would land, and at this point the tiles were no longer waterproof, and so the space shuttle would land and it could just randomly rain before they had a chance to roll the space shuttle back inside, which means the tiles would soak up all the water and then they would have to go through and manually suck the water out of the tiles, and then go through the process of re-waterproofing the tiles before the next launch, so the space shuttle was absolutely not rapidly reusable at all.

I keep sounding the alarm over this, but I don't understand why the SpaceX community isn't talking about this more often!!!?

I bet you SpaceX has not solved this problem. They couldn't solve this back in the '70s and they probably still can't. Which means Starship will never ever be rapidly reusable.

So they need some kind of novel solution, I don't know, maybe Stoke Space has the solution for a rapidly reusable heat shield? I've had my eye on them.

"There was a thread about this on X I read a while back,"

Yeah this thread right here https://x.com/DrPhiltill/status/1801435436478304472?t=SGKDgMKuQf6VNvqWCZ3XPg&s=19

Dr. Phil Metzger sure is a wealth of knowledge.

[steveleach]

Somebody really should let SpaceX know that sometimes it rains outside.

[aporigine]

Thunderf00t videos are not worth engaging with.

Well I did say it was a "very negative". I was only interested in the waterproofing part. Oxygen atoms on the outside of SiO2 bonds with water which makes it hydrophilic. So bonding a methyl group to the oxygen makes it hydrophobic. bonding here meaning weak hydrogen bonding. So I was just trying to understand if there was a chemical that doesn't "boil off" under heat.

It looks like SiC is water loving. Sort of like CaC that we as kids used to make are canons go boom.
So what is dream chaser using to protect their SiC heat tiles?

from google ai:

The Dream Chaser heat shield uses a new thermal protection system (TPS) of approximately 2,000 larger, composite tiles made of a proprietary mix of silicon carbide and carbon fiber to withstand extreme re-entry temperatures.

Silicon carbide is not hydrophilic and is an excellent refractory, even in an oxidizing atmosphere, thanks to passivation by silica It is a good conductor of heat, so must be coformulated with insulating refractories. It has excellent emissivity.

Unlike the Shuttle’s “silica gel” (very thirsty if not silanized) tiles, Spacex’s Ship tiles adsorb little water and do not need the toxic, laborious and expensive procedure needed to make Shuttle’s heat shield flyable again.

Finally, calcium “carbide” is really calcium acetylide with an empirical formula of CaC2. It reacts with water to form acetylene, which easily detonates in air.

[SpaceManJoe]

Thunderfoot made a video and talked about heat tiles and waterproofing? Link please?

[woods170]

Thunderfoot made a video and talked about heat tiles and waterproofing? Link please?

Do yourself a favour and don't go there. Thunderfoot videos are usually 99% crap. Providing a link to it would actually serve to degrade the quality of this forum.

[rsdavis9]

Silicon carbide is not hydrophilic and is an excellent refractory, even in an oxidizing atmosphere, thanks to passivation by silica It is a good conductor of heat, so must be coformulated with insulating refractories. It has excellent emissivity.

Unlike the Shuttle’s “silica gel” (very thirsty if not silanized) tiles, Spacex’s Ship tiles adsorb little water and do not need the toxic, laborious and expensive procedure needed to make Shuttle’s heat shield flyable again.

Finally, calcium “carbide” is really calcium acetylide with an empirical formula of CaC2. It reacts with water to form acetylene, which easily detonates in air.

So do you have any links for this? From what I know glass (SiO2) is hydrophyllic. I thought the shuttle tiles were mostly glass and so were the spacex tiles. There are a lot of glasses.
SiO2 with Ca
SiO2 with K
SiO2 with Na
SiO2 with B

This link from Dr Phil Metzger seems reliable and informative.
https://x.com/DrPhiltill/status/1530776472675405824?s=20

BTW thanks for the corrections...

[aporigine]

~snip~
So do you have any links for this? From what I know glass (SiO2) is hydrophyllic. I thought the shuttle tiles were mostly glass and so were the spacex tiles. There are a lot of glasses.
SiO2 with Ca
SiO2 with K
SiO2 with Na
SiO2 with B

This link from Dr Phil Metzger seems reliable and informative.
https://x.com/DrPhiltill/status/1530776472675405824?s=20

BTW thanks for the corrections...

https://en.wikipedia.org/wiki/LI-900

I know; it’s Wiki — but contains the key info. Most of Shuttle is covered in HRSI (hi-temp reusable surface insulation) whose bulk is made up of pure silica fiber, branded LI-900. This is quite hydrophilic and necessitates that laborious silanization (spellcheck was gonna substitute islamization, something quite different … ) of each tile between flights.

N. b. unlike the typical glasses we encounter, e.g. Pyrex and soda lime, it does not contain the common glass adjuncts you listed. Silica fiber is glassy (amorphous) in nature.

Afaict Spacex tiles are alumina-heavy. Less thirsty and do not need treatment between flights.

[SpaceManJoe]

So someone on X asked Phil Metzger
"Phil Metzger, so has SpaceX solved this problem? Will you please talk about this and raise awareness about this problem? Because honestly, I don't think SpaceX has, I don't think they have solved it. Or have they?"

Phil Metzger replied
"I haven’t heard any inside information from SpaceX about it, so I don’t know how they are handling it. I wish I knew, though." https://x.com/DrPhiltill/status/1989850423386411409?t=87AA3QVobbd0gTHKQ7r42Q&s=19

Then Phil was asked
"Is it even possible to solve it? Do you think SpaceX has actually solved it using modern tech?"

To which he replied
"On the Shuttle, the tile technicians sprayed waterproofing spray into each tile one-by-one before every launch. It would burn out during the heat of re-entry so it had to be reapplied each time. If there is a new type of tile that is inherently hydrophobic then the spray wouldn’t be needed, but I don’t know if there is a material that would be suitable. The tiles are made of silica fiber, and silica is strongly hydrophilic (loves water and pulls it into its pore spaces). I worked on tile tech briefly about 20 years ago and haven’t since then so I haven’t heard news about any new inventions. I suspect we don’t have a new material like that. I’m sorry I really don’t know more than that." https://x.com/DrPhiltill/status/1990166047786164513?t=uT6EbcZoVosd5egV-VgPKg&s=19

So that is the question, has SpaceX actually solved this problem using modern tech? Will someone please just ask Elon Musk already? I can't believe no one has actually asked Elon Musk about this yet. Because this is a big deal, they can't have a rapidly reusable Starship if they have to waterproof the heat tiles after every single launch.

On the space shuttle, each individual heat tile had a hole on the top, and that hole was there so they could squirt a chemical into it to waterproof it, and they had to do this after every single launch because this chemical would burn off during re-entry.

Now I don't believe the heat tiles on Starship have holes in them, so maybe SpaceX has solved it?

Will someone please just outright ask Elon about this?

[rsdavis9]

Now I don't believe the heat tiles on Starship have holes in them, so maybe SpaceX has solved it?

Will someone please just outright ask Elon about this?

Or just bring out the ship to be stacked just before launch. They do have a shelter 3.2km away.

[Nonexistence]

What is the approximate weight of water entrapped within the two layers beneath the tiles?
The tiles float so they must not hold much.

Seems like a substantial amount of water could be held there……

[OTV Booster]

Now I don't believe the heat tiles on Starship have holes in them, so maybe SpaceX has solved it?

Will someone please just outright ask Elon about this?

Or just bring out the ship to be stacked just before launch. They do have a shelter 3.2km away.

Shelter is expensive. How many ships, how long for turnaround, what launch rate? AIUI the gigabay has 24 work cells.


Figure on one gigabay sized shelter but of less height, to shelter 24 ships. Would still need one or more cranes. Other equipment that might stay is a hard one.


Reality may force the shelter to double as a tile referb shop. Maybe painstakingly through, maybe only calling for touchup, maybe 'we don't need no steenking refurb'.


If a lot of referb isn't necessary maybe store them outside and have a ship sized oven to bake the tiles out before launch. Maybe build a bakery next door and use waste heat to bake the ship.


I have every expectation that SX can establish a high launch tempo with Starship and low expectation of a shallow pipeline. It'll get better over time but a 120 day pipeline isn't unreasonable for the first year or two following first reuse.

[Vultur]

Are we sure that waterproofing is strictly needed?

[xvel]

Since the inception of the starship, there has been no official statement on the matter at all, so I think it is safe to assume at this point that this is a deliberate action.

[Stan-1967]

Has anyone considered that the recent utilization of metals in tiles could potentially contain a mechanism to be made hydrophobic by the re-entry plasma by making native oxides on the tiles?   Basically the metal containing tiles would "self assemble" oxide surfaces that are hydrophobic during the re-entry. 

[SpaceManJoe]

Has anyone considered that the recent utilization of metals in tiles could potentially contain a mechanism to be made hydrophobic by the re-entry plasma by making native oxides on the tiles?   Basically the metal containing tiles would "self assemble" oxide surfaces that are hydrophobic during the re-entry.

Maybe SpaceX has come up with some super clever ingenious workaround like that. I wish someone would just outright ask Elon Musk about it?

[meekGee]

Has anyone considered that the recent utilization of metals in tiles could potentially contain a mechanism to be made hydrophobic by the re-entry plasma by making native oxides on the tiles?   Basically the metal containing tiles would "self assemble" oxide surfaces that are hydrophobic during the re-entry.

Maybe SpaceX has come up with some super clever ingenious workaround like that. I wish someone would just outright ask Elon Musk about it?

If recycle time really drops, maybe extra ships don't come down until needed, so basically spend most of their time in orbit...

[Vettedrmr]

Maybe SpaceX has come up with some super clever ingenious workaround like that. I wish someone would just outright ask Elon Musk about it?

EM has said multiple times that the heat shield is among the hardest nuts to crack in full reusability.  If they've made progress on that tech, it's going to be among the most proprietary data they have, and they won't be sharing it publicly.

[DanClemmensen]

Has anyone considered that the recent utilization of metals in tiles could potentially contain a mechanism to be made hydrophobic by the re-entry plasma by making native oxides on the tiles?   Basically the metal containing tiles would "self assemble" oxide surfaces that are hydrophobic during the re-entry.

Maybe SpaceX has come up with some super clever ingenious workaround like that. I wish someone would just outright ask Elon Musk about it?

If recycle time really drops, maybe extra ships don't come down until needed, so basically spend most of their time in orbit...

This would likely require sophisticated boiloff prevention for all ships. I think we have been assuming that most ships do not have that.

[JamesH65]

Has anyone considered that the recent utilization of metals in tiles could potentially contain a mechanism to be made hydrophobic by the re-entry plasma by making native oxides on the tiles?   Basically the metal containing tiles would "self assemble" oxide surfaces that are hydrophobic during the re-entry.

Maybe SpaceX has come up with some super clever ingenious workaround like that. I wish someone would just outright ask Elon Musk about it?

Most on here have exactly the same access to Musk as you do, so why don't you ask him yourself? I hear he has something to do with something called X which appears to be a way of getting in touch.

That said, I agree with the above; if they have solved the problem, it is probably one of their most important commercial secrets. I would not be saying anything about it at all. Which appears to be what they are doing.

Although not saying anything is also what they would do if they haven't solved the problem.

Maybe they are just going to have an enormous umbrella to keep it dry.