Starship heat shield

[john smith 19]

For „field repairs“ on mars they could easily use dissimilar materials (for example ablative materials). AFAIK Elon also said mars ships might have a heatshield that‘s different from what your average daily-use starship will have. Most Starships flying to mars might only use their heatshield once.

That opens up the field considerably

What people may not realize is that NASA developed conformable variants of both PICA and SIRCA ablators.

This stuff is like stiff foam sheet that can be cut. This can radically simplify TPS as normal materials are hard and rigid. So if you've got a surface with significant curvature to wrap round you either
a) Mfg a thick billet and machine it to shape
b) Thin smallish tiles that conform to the shape but need gap fillers.
IRL most objects will need gap fillers (IIRC Stardust was able to do the heat shield with a single piece, but that was right on the limit of the size they could mfg)
Putting an opening in these materials (for a door) needs serious pre-planning.

OTOH with the flexible version it's more like laying a carpet and cutting a flap to access floor mounted power or data sockets.

I'll also note that ablator panels were looked at for STS. They decided it could be viable provided you didn't have to gun the stuff into a honeycomb one cell at a time, although it would need stiffener walls, with the ablative making continuous channels between them.

[Vemaster]

The actual thickness of the tiles is ~9mm and they are placed on the sides/spikes with a height of ~37 mm:

[spacexfanatic]

Any data about the weight of the heatshield materials per square meter on SS. thanks.

[rsdavis9]

Any data about the weight of the heatshield materials per square meter on SS. thanks.

there is a thread for that. Rafael did a great job.

https://forum.nasaspaceflight.com/index.php?topic=50049.0

Is there a thread somewhere that gives the raptor specs. I know there is a post somewhere in the raptor thread that has it but it is very hard to find? I think livingjw did a very good post in there?

[Crispy]

Hi, i'm new in this forum

i have notice this article from "the nextbig future" :
'Magnet Enhanced Aerocapture Would Enable 39 Day Mars Crewed Flights' (my enhanced)
I think it will be useful for Starship, someone could explain how it works

Welcome to NSF! There's a good thread on magnetoshells here:
https://forum.nasaspaceflight.com/index.php?topic=29912.0

[spacexfanatic]

Any data about the weight of the heatshield materials per square meter on SS. thanks.

there is a thread for that. Rafael did a great job.

https://forum.nasaspaceflight.com/index.php?topic=50049.0

Is there a thread somewhere that gives the raptor specs. I know there is a post somewhere in the raptor thread that has it but it is very hard to find? I think livingjw did a very good post in there?

10 tons of heatshielding tiles for SS, a lot of work ahead for weight saving.

[rsdavis9]

Any data about the weight of the heatshield materials per square meter on SS. thanks.

there is a thread for that. Rafael did a great job.

https://forum.nasaspaceflight.com/index.php?topic=50049.0

Is there a thread somewhere that gives the raptor specs. I know there is a post somewhere in the raptor thread that has it but it is very hard to find? I think livingjw did a very good post in there?

Here is the best I can come up to answer my own question:

https://forum.nasaspaceflight.com/index.php?topic=47506.600

[livingjw]

Any data about the weight of the heatshield materials per square meter on SS. thanks.

there is a thread for that. Rafael did a great job.

https://forum.nasaspaceflight.com/index.php?topic=50049.0

Is there a thread somewhere that gives the raptor specs. I know there is a post somewhere in the raptor thread that has it but it is very hard to find? I think livingjw did a very good post in there?

Here is the best I can come up to answer my own question:

https://forum.nasaspaceflight.com/index.php?topic=47506.600

I don't know what chamber pressure they have demonstrated now. It wouldn't surprise me if they have increased chamber pressure somewhat. 270 bar chamber pressure would give them 1.83 MN SL, 1.96 MN vac.

John

[livingjw]

The actual thickness of the tiles is ~9mm and they are placed on the sides/spikes with a height of ~37 mm:

- The ~9 mm you are measuring might just be the depth to the lip. I speculated that the lip is there to hold gap filler. The outer coating, if similar to AETB shuttle tile, is very thin, ~.25 mm.

- If what we are seeing is an ablative outer cover it would be thicker. Might be 9 mm.

- Many mysteries yet to sorted out. Thanks for the estimates.

John

[livingjw]

Having just done some TPS mass estimation work, my latest estimations are leaning to an average areal density of ~13 kg/m^2

John

[northstar]

Having just done some TPS mass estimation work, my latest estimations are leaning to an average areal density of ~13 kg/m^2

John

So a total mass of about 8700 kg for one half the Starship

[oiorionsbelt]

Having just done some TPS mass estimation work, my latest estimations are leaning to an average areal density of ~13 kg/m^2

John

Does this include the studs or sheet metal surround mounting system?

[john smith 19]

Any data about the weight of the heatshield materials per square meter on SS. thanks.

there is a thread for that. Rafael did a great job.

https://forum.nasaspaceflight.com/index.php?topic=50049.0

Is there a thread somewhere that gives the raptor specs. I know there is a post somewhere in the raptor thread that has it but it is very hard to find? I think livingjw did a very good post in there?

10 tons of heatshielding tiles for SS, a lot of work ahead for weight saving.

Not necessarily.

It depends if that's within the allocated mass for this subsystem.

If it is then that's good enough to be going on with.

Get something flying then measure it, then see what (if) level of optimization is needed.

[livingjw]

Having just done some TPS mass estimation work, my latest estimations are leaning to an average areal density of ~13 kg/m^2

John

Does this include the studs or sheet metal surround mounting system?

It would include the weight of short attachment studs. I have not done an analysis of a sheet metal edge support system. I think it would be a little heavier.

John

[aceshigh]

Couldn´t they just use some material painted... like Starlite? It seems a chemist guy rediscovered the formula and posted it on Youtube... that, or something else.

Even if they are all the same hexagonal tiles, won´t they have to check them all after each landing? Won´t that and replacing any damaged tile still be expensive and labor intensive?

[rsdavis9]

Couldn´t they just use some material painted... like Starlite? It seems a chemist guy rediscovered the formula and posted it on Youtube... that, or something else.

Even if they are all the same hexagonal tiles, won´t they have to check them all after each landing? Won´t that and replacing any damaged tile still be expensive and labor intensive?

I would think a visual check with camera would be enough.

Now the real question is what would a missing tile(fell off early in reentry) look like for damage.
1. heat would burn through the 4mm steel.
2. heat would permanently weaken steel but no hole.

So if just weakened it could be cut out and patched.

So for a hole and the fact that they have header tanks would this doom the landing? Maybe the depressurized tank would not be able to handle the aero forces?

[envy887]

Couldn´t they just use some material painted... like Starlite? It seems a chemist guy rediscovered the formula and posted it on Youtube... that, or something else.

Even if they are all the same hexagonal tiles, won´t they have to check them all after each landing? Won´t that and replacing any damaged tile still be expensive and labor intensive?

I would think a visual check with camera would be enough.

Now the real question is what would a missing tile(fell off early in reentry) look like for damage.
1. heat would burn through the 4mm steel.
2. heat would permanently weaken steel but no hole.

So if just weakened it could be cut out and patched.

So for a hole and the fact that they have header tanks would this doom the landing? Maybe the depressurized tank would not be able to handle the aero forces?

I doubt they would cut into the tank wall, that just unnecessarily weakens it further.. They could weld a doubler sheet over that spot, and then put a (slightly thinner) tile over the whole mess.

[SteveU]

Couldn´t they just use some material painted... like Starlite? It seems a chemist guy rediscovered the formula and posted it on Youtube... that, or something else.

Even if they are all the same hexagonal tiles, won´t they have to check them all after each landing? Won´t that and replacing any damaged tile still be expensive and labor intensive?

I would think a visual check with camera would be enough.

Now the real question is what would a missing tile(fell off early in reentry) look like for damage.
1. heat would burn through the 4mm steel.
2. heat would permanently weaken steel but no hole.

So if just weakened it could be cut out and patched.

So for a hole and the fact that they have header tanks would this doom the landing? Maybe the depressurized tank would not be able to handle the aero forces?

I doubt they would cut into the tank wall, that just unnecessarily weakens it further.. They could weld a doubler sheet over that spot, and then put a (slightly thinner) tile over the whole mess.

Why not cut out the bad section - no different than the square access holes they are using now.

[envy887]

Couldn´t they just use some material painted... like Starlite? It seems a chemist guy rediscovered the formula and posted it on Youtube... that, or something else.

Even if they are all the same hexagonal tiles, won´t they have to check them all after each landing? Won´t that and replacing any damaged tile still be expensive and labor intensive?

I would think a visual check with camera would be enough.

Now the real question is what would a missing tile(fell off early in reentry) look like for damage.
1. heat would burn through the 4mm steel.
2. heat would permanently weaken steel but no hole.

So if just weakened it could be cut out and patched.

So for a hole and the fact that they have header tanks would this doom the landing? Maybe the depressurized tank would not be able to handle the aero forces?

I doubt they would cut into the tank wall, that just unnecessarily weakens it further.. They could weld a doubler sheet over that spot, and then put a (slightly thinner) tile over the whole mess.

Why not cut out the bad section - no different than the square access holes they are using now.

Still need the doubler around the cutout, so what does it gain?

[Slarty1080]

Looking at the possibilities for tiling the flippers it seems the more curves the more tiles required. If they can keep the edges relatively straight it will help minimise the number of tiles required. That said in the battle between aerodynamics and tile count I think aerodynamics wins.

One other thing, with the standard tiles which is the best configuration for the main tile type? Hexagon flat sides aligned upwards or hexagon vertices pointing upwards? Currently the test patch is installed flat side aligned upwards, but I would have thought the other orientation would provide less vertical tile gaps.