Author Topic: Starship heat shield  (Read 1033770 times)

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 6715
  • California
  • Liked: 8141
  • Likes Given: 5184
Re: Starship heat shield
« Reply #1060 on: 03/19/2021 10:27 pm »
Hi everyone,

I have a question regarding the heat shield. How will windward thrusters integrate into the tile mesh? Will they cut holes on some of the tiles where they can poke out a thruster? I assume those thrusters would be made out of some very temp tolerant material.

Like on Shuttle, all thrusters will likely be on the leeward(?) side (or edge of it), but angled/canted so they can produce thrust in the desired direction.
« Last Edit: 03/19/2021 10:32 pm by Lars-J »

Offline HVM

  • Full Member
  • ****
  • Posts: 646
  • Finland
  • Liked: 1020
  • Likes Given: 480
Re: Starship heat shield
« Reply #1061 on: 03/19/2021 10:38 pm »
Lars is a Ninja...

Like with the Space Shuttle Orbiter, there will be no thrusters directly pointing or in windward side, instead there will be thrusters with ~45 dec of windward vector in both side and they are used simultaneously, or so I guess. Also you have already seen tiles with pentagon configuration, so there will be more in each special case...
« Last Edit: 03/19/2021 10:40 pm by HVM »

Offline OTV Booster

  • Senior Member
  • *****
  • Posts: 4402
  • Terra is my nation; currently Kansas
  • Liked: 3017
  • Likes Given: 4934
Re: Starship heat shield
« Reply #1062 on: 03/19/2021 11:31 pm »
Hi everyone,

I have a question regarding the heat shield. How will windward thrusters integrate into the tile mesh? Will they cut holes on some of the tiles where they can poke out a thruster? I assume those thrusters would be made out of some very temp tolerant material.
And welcome to the forum.
We are on the cusp of revolutionary access to space. One hallmark of a revolution is that there is a disjuncture through which projections do not work. The thread must be picked up anew and the tapestry of history woven with a fresh pattern.

Offline joek

  • Senior Member
  • *****
  • Posts: 4412
  • Liked: 2269
  • Likes Given: 950
Re: Starship heat shield
« Reply #1063 on: 03/20/2021 03:08 am »
They still need to do the weld between barrel sections. So I would guess one row of custom fit tiles. You got to cover the weld! Not too bad. It also allows tiling to occur on many barrels at the same time.

Based on photos, there is a fibrous mat below the tiles which appears to be semi-continuous (not per-tile).  May complicate matters as it is not simply attaching a tile to points on the SS skin.

Offline HVM

  • Full Member
  • ****
  • Posts: 646
  • Finland
  • Liked: 1020
  • Likes Given: 480
Re: Starship heat shield
« Reply #1064 on: 03/20/2021 09:28 pm »
Tiles on the flap(s), is this discussed here? I didn't find it. Two sizes and same pattern as in SN10 body.
« Last Edit: 03/20/2021 09:32 pm by HVM »

Offline enbandi

  • Full Member
  • ****
  • Posts: 652
  • Hungary
  • Liked: 786
  • Likes Given: 385
Re: Starship heat shield
« Reply #1065 on: 03/20/2021 09:42 pm »
Tiles on the flap(s), is this discussed here? I didn't find it. Two sizes and same pattern as in SN10 body.

And they are on the wrong side (leeward nor windward). Was similar arrangement on SN10. Guess they want to test the tiles, but dont want to mess with aerodinamics of the flaps (yet).
« Last Edit: 03/20/2021 09:44 pm by enbandi »

Offline Keldor

  • Full Member
  • ****
  • Posts: 694
  • Colorado
  • Liked: 836
  • Likes Given: 117
Re: Starship heat shield
« Reply #1066 on: 03/20/2021 11:30 pm »
Tiles on the flap(s), is this discussed here? I didn't find it. Two sizes and same pattern as in SN10 body.

And they are on the wrong side (leeward nor windward). Was similar arrangement on SN10. Guess they want to test the tiles, but dont want to mess with aerodinamics of the flaps (yet).

It might not be feasible to test the tiles on the windward side without making a full heatshield for at least the fin.  The problem is that without the proper pieces on the edges, the tiles are not very aerodynamic, and so subjecting them to the airflow could easily rip them all off like shingles in a tornado.

The tiles on the centerline don't face this problem, since they are, to some extent inside a cushion of relatively still air.  But the flaps will probably have the highest sideways airflow at the surface of anywhere on the vehicle.

Offline Pete

  • Full Member
  • ****
  • Posts: 767
  • Cubicle
  • Liked: 1026
  • Likes Given: 395
Re: Starship heat shield
« Reply #1067 on: 03/21/2021 07:55 am »
Tiles on the flap(s), is this discussed here? I didn't find it. Two sizes and same pattern as in SN10 body.

And they are on the wrong side (leeward nor windward). Was similar arrangement on SN10. Guess they want to test the tiles, but dont want to mess with aerodinamics of the flaps (yet).

Maybe testing the vibration aspects of flap mounting, without the problems of airflow added to the picture?

The tiles on the flaps will be an interesting problem in any case, as there are all sorts of sharp edges, lateral airflow, different/higher mechanical stresses, completely different thermal environment (no backing cryo tank), etc.
I would actually be a bit surprised if the exact same solution can be used for tankbody and flap shielding.

Offline enbandi

  • Full Member
  • ****
  • Posts: 652
  • Hungary
  • Liked: 786
  • Likes Given: 385
Re: Starship heat shield
« Reply #1068 on: 03/21/2021 10:01 am »
...
It might not be feasible to test the tiles on the windward side without making a full heatshield for at least the fin.  The problem is that without the proper pieces on the edges, the tiles are not very aerodynamic, and so subjecting them to the airflow could easily rip them all off like shingles in a tornado.
.....

If you are right, that defines a cascading error behaviour. If one tile fail, neighbours will be peeled off easily by airflow an so...
I think this is something, what they want to avoid by engineering out of the system (tolerant tiles or so). And if such behaviour exists they migh also want to test it against.
But its my opinion only, you can be as well as right.

Offline Broccoli32

  • Member
  • Posts: 64
  • Liked: 215
  • Likes Given: 361
Re: Starship heat shield
« Reply #1069 on: 03/23/2021 01:16 am »
Large chunks out of two tiles broke off during the static fire, the larger patch also had small chips in several tiles.

Photo credit: Nomadd

Offline Vultur

  • Full Member
  • ****
  • Posts: 1800
  • Liked: 653
  • Likes Given: 151
Re: Starship heat shield
« Reply #1070 on: 03/23/2021 04:38 am »
That seems troubling, as I'd think the static fire would be less stress than actually flying. (Or am I wrong about that?)

The heat shield is my big concern for Starship meeting its goals (with Raptor reliability/maintenance being second). It will need to do vastly better than Shuttle level of maintenance "finicky-ness", and much better than the demonstrated safety/reliability (1 reentry-related fatal accident out of 135 flights) as well, to meet its goals.

Do we know why the transpiration cooling was abandoned?

Online ThatOldJanxSpirit

  • Full Member
  • ****
  • Posts: 786
  • Liked: 1123
  • Likes Given: 2504
Re: Starship heat shield
« Reply #1071 on: 03/23/2021 05:29 am »
That seems troubling, as I'd think the static fire would be less stress than actually flying. (Or am I wrong about that?)

The heat shield is my big concern for Starship meeting its goals (with Raptor reliability/maintenance being second). It will need to do vastly better than Shuttle level of maintenance "finicky-ness", and much better than the demonstrated safety/reliability (1 reentry-related fatal accident out of 135 flights) as well, to meet its goals.

Do we know why the transpiration cooling was abandoned?

The static fire acoustic environment, with three engines at high thrust operating close to the ground for a few seconds, should be worse than Starship will see in orbital operations. At staging engines will be starting in near vacuum. For landing it should only have two engines operating at minimal thrust.

Offline Slarty1080

  • Senior Member
  • *****
  • Posts: 2587
  • UK
  • Liked: 1711
  • Likes Given: 762
Re: Starship heat shield
« Reply #1072 on: 03/23/2021 08:21 am »
That seems troubling, as I'd think the static fire would be less stress than actually flying. (Or am I wrong about that?)

The heat shield is my big concern for Starship meeting its goals (with Raptor reliability/maintenance being second). It will need to do vastly better than Shuttle level of maintenance "finicky-ness", and much better than the demonstrated safety/reliability (1 reentry-related fatal accident out of 135 flights) as well, to meet its goals.

Do we know why the transpiration cooling was abandoned?
Remember that this is a prototype used for a variety of testing. The large central bank of tiles all appear to be attached via the push fit two prong system and I suspect will be used for most of the tiling. But the smaller patches seem to have a different attachment mechanism, perhaps something they were testing to see if it worked better (it doesn't) or might be suitable for certain areas (it isn't). So probably useful info for them.

Part of the problem is cost so they probably want to try the cheapest solutions first and only start experimenting with more costly or complex set ups if they have to. I would expect to see a range of different options being tested out as time goes on.

Transpiration cooling is still in the waiting in the wings if needed, but it is inherently inefficient as it will use consumables and its probably also involves more complexity and cost. I predict that either we won't see it or if we do it will be a lot later on the high energy areas after they have tried a lot of other options.
« Last Edit: 03/23/2021 08:27 am by Slarty1080 »
My optimistic hope is that it will become cool to really think about things... rather than just doing reactive bullsh*t based on no knowledge (Brian Cox)

Offline Alberto-Girardi

Re: Starship heat shield
« Reply #1073 on: 03/23/2021 08:26 am »
Large chunks out of two tiles broke off during the static fire, the larger patch also had small chips in several tiles.

Photo credit: Nomadd

Did we see similar things with other prototipes?

It is not a good sign IMO, because there will be tiles closer to the engines. Static fire environment is harsher than launch one, but this issue has to be solved.

Could they be testing another tile attachment system (that didn't work)?
I want to become an Aerospace Engineer!

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 7426
  • Germany
  • Liked: 2326
  • Likes Given: 2852
Re: Starship heat shield
« Reply #1074 on: 03/23/2021 08:28 am »
Do we know why the transpiration cooling was abandoned?

If I remember correctly, Elon Musk said they have come up with a low cost heat shield tile production method, that beats the metal transpiration cooling design.

To me he still gives the impression he likes the transpiration design.

Offline HVM

  • Full Member
  • ****
  • Posts: 646
  • Finland
  • Liked: 1020
  • Likes Given: 480
Re: Starship heat shield
« Reply #1075 on: 03/23/2021 08:47 am »
Both fractured tile(s) -batches are bond with red adhesive, and have felt pads. Interesting to see that Y-like structure inside the tile is not some space-age-spring-suspended-contraption but three metal fasteners from local hardware store...
« Last Edit: 03/23/2021 04:03 pm by HVM »

Offline _MECO

  • Full Member
  • ****
  • Posts: 722
  • Central KY, USA
  • Liked: 775
  • Likes Given: 447
Re: Starship heat shield
« Reply #1076 on: 03/23/2021 12:35 pm »
Both fractured tile(s) -batches are bond with red adhesive, and have felt pads. Interesting to see that Y-like structure inside the tile is not some space-time-spring-suspended-contraption but three metal fasteners from local hardware store...

Aha! I knew it! A little ago I made a post where I assumed that Starship TPS tiles had a triangular metal skeleton in them. This particular example may have been adhered with glue of some kind, yes, but if the overall structure remains the same for the mechanically attached tiles, then it bodes well for in-the-field serviceability. Replacing broken tiles on orbit, or on the surface of Mars or wherever can be as simple as digging over the mounting spots with a screwdriver until the mounting points on the skeleton are exposed, prying the studs open with said tool, removing the tile, and then snapping a new one in place.

Offline Nomadd

  • Senior Member
  • *****
  • Posts: 8539
  • Highway Whatever
  • Liked: 58066
  • Likes Given: 1130
Re: Starship heat shield
« Reply #1077 on: 03/23/2021 01:20 pm »
Both fractured tile(s) -batches are bond with red adhesive, and have felt pads. Interesting to see that Y-like structure inside the tile is not some space-time-spring-suspended-contraption but three metal fasteners from local hardware store...
The mounting Y is just buried in that crumbly white part with holes to the attachment points. The white stuff is giving way when they break. It's almost chalk like, but much lighter.
 I don't know if the smaller tiles, or the ones with the red stuff which don't seem to be failing, are made the same way. But they're obviously testing variations and not just sticking the same thing up every time. Even if they get a batch with no failures, they'll probably keep trying new materials, construction and mountings, so assuming they can't figure it out is unwarranted.
 Finding new ways to break them is just more data.

 I can see where static fires with the ship being held down by those six mounting points might flex the hull more than flying.
« Last Edit: 03/23/2021 01:31 pm by Nomadd »
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline _MECO

  • Full Member
  • ****
  • Posts: 722
  • Central KY, USA
  • Liked: 775
  • Likes Given: 447
Re: Starship heat shield
« Reply #1078 on: 03/23/2021 01:45 pm »
Both fractured tile(s) -batches are bond with red adhesive, and have felt pads. Interesting to see that Y-like structure inside the tile is not some space-time-spring-suspended-contraption but three metal fasteners from local hardware store...
The mounting Y is just buried in that crumbly white part with holes to the attachment points. The white stuff is giving way when they break. It's almost chalk like, but much lighter.
 I don't know if the smaller tiles, or the ones with the red stuff which don't seem to be failing, are made the same way. But they're obviously testing variations and not just sticking the same thing up every time. Even if they get a batch with no failures, they'll probably keep trying new materials, construction and mountings, so assuming they can't figure it out is unwarranted.
 Finding new ways to break them is just more data.

 I can see where static fires with the ship being held down by those six mounting points might flex the hull more than flying.

Lighter than chalk? That's amazingly fragile.

Offline AnalogMan

  • Member
  • Senior Member
  • *****
  • Posts: 3349
  • Cambridge, UK
  • Liked: 1446
  • Likes Given: 44
Re: Starship heat shield
« Reply #1079 on: 03/23/2021 03:49 pm »
Both fractured tile(s) -batches are bond with red adhesive, and have felt pads. Interesting to see that Y-like structure inside the tile is not some space-time-spring-suspended-contraption but three metal fasteners from local hardware store...
The mounting Y is just buried in that crumbly white part with holes to the attachment points. The white stuff is giving way when they break. It's almost chalk like, but much lighter.
 I don't know if the smaller tiles, or the ones with the red stuff which don't seem to be failing, are made the same way. But they're obviously testing variations and not just sticking the same thing up every time. Even if they get a batch with no failures, they'll probably keep trying new materials, construction and mountings, so assuming they can't figure it out is unwarranted.
 Finding new ways to break them is just more data.

 I can see where static fires with the ship being held down by those six mounting points might flex the hull more than flying.

Lighter than chalk? That's amazingly fragile.

A Density comparison between chalk and Shuttle Orbiter tiles.

Chalk 156 lb/ft3 typically (varies from ~ 112 to 168 lb/ft3)

Shuttle Orbiter tiles:

LI-900 (black tiles on underside) 9 lb/ft3
LI-2200 (black higher strength around windows & landing gear doors) 22 lb/ft3

FRCI-12 (improved tiles to replace some LI tiles) 12 lb/ft3

LRSI-9  (white tiles on upper surfaces) 9 lb/ft3
LRSI-12 (white tiles on upper surfaces) 12 lb/ft3

BRI-18 (strongest & toughest tile produced, replacement for critical areas)  18 lb/ft3

Water 62.4 lb/ft3
Styrofoam packaging and insulation typically 1 to 2 lb/ft3

Conversion to metric:

1 lb/ft3 is equivalent to 0.016 g/cm3 or 16.0 kg/m3
« Last Edit: 03/24/2021 10:19 am by AnalogMan »

Tags:
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1