Starship V2 Versus Space Shuttle Tile damage

[Lee Jay]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

[ellindsey]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

They did deliberately remove multiple tiles on this flight just to see how well it would hold up. The Shuttle didn't do too well with missing tiles either.

[SpaceLizard]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

They did deliberately remove multiple tiles on this flight just to see how well it would hold up. The Shuttle didn't do too well with missing tiles either.

Pretty sure the shuttle was also never deliberately re-entered in the most stressful orientations and trajectories it could attempt just to see if it would blow up or not, y'know cause there were always people on board. Starship has the luxury of being forced to endure things in its test flights that the shuttle would never have even imagined.

[xvel]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

lol, you don't remember because when it was damaged to the extent starship starts with (there was like 80 tiles removed before launch on purpose) it disintegrated on reentry, starship in the other hand can reenter and land quite precisely with extensive damage (which is in large part induced deliberately), and it did that multiple times already so it's definitely not a fluke

[catdlr]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

lol, you don't remember because when it was damaged to the extent starship starts with (there was like 80 tiles removed before launch on purpose) it disintegrated on reentry, starship in the other hand can reenter and land quite precisely with extensive damage (which is in large part induced deliberately), and it did that multiple times already so it's definitely not a fluke

Lee Jay,

I feel so bad that your and other members don't search and find out that even the space shuttle had its moments where numerous tiles came off and we almost lost a ship.  You need to read up on STS-027 on the form.

When Atlantis touched down at Edwards Air Force Base on December 6, 1988, inspection revealed the craft had sustained slightly more than 700 individual tile impacts. The damage was concentrated on the lower surface tiles of the right-hand side. One complete tile was found missing from the damaged area below the crew compartment, and an insulation panel was missing from the right Orbital Maneuvering System (OMS) pod. The extent of damage made it necessary to ascertain the precise cause of the damage before the next flight of the shuttle.

https://forum.nasaspaceflight.com/index.php?topic=29360.msg926865#msg926865

[1]

Respectfully request that we avoid sidetracking the thread. The shuttle and starship are drastically different vehicles.

Of note to me for this flight is the fact that some tiles were omitted in groups of four rather than one or two, and explicit mentioning that some of the removed tiles also had the ablative layer below removed as well exposing bare metal on the leeward side of the ship. Obviously both of these things have occured on previous flights from damage incurred during reentry, but this appears to be a successful test of what happens when both features are out in the breeze from the get-go.

I wouldn't worry about continuing to see damage on the test flights when it seems clear that they're probing to see how much damage this thing can actually take. Hell, if they weren't eager to start getting these things back, it wouldn't have surprised me if they continued to chip away even more at the shield just to see how far they can go before one does end up disintigrating on reentry. So far, all we know that a skeletonized flap is only enough to nudge it off target some 10s of km.

Here's my ridiculous and wasteful request for any spacex-ers that might be reading: pair up all of the reentry cameras so I get a binocular livestream that I can watch on my VR set. Pretty please?

[Herb Schaltegger]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

lol, you don't remember because when it was damaged to the extent starship starts with (there was like 80 tiles removed before launch on purpose) it disintegrated on reentry, starship in the other hand can reenter and land quite precisely with extensive damage (which is in large part induced deliberately), and it did that multiple times already so it's definitely not a fluke

With respect (and noting we're getting far off-topic), the damage to Columbia on STS-107 was far greater and much more intensively localized than anything SpaceX has attempted with any Starship entry experiment. Punch a square-foot hole in the leading edge of one of Starship's flaps and let it enter from an apogee of 280km and see how it does before you make ill-informed and inaposite comparisons.

[catdlr]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

lol, you don't remember because when it was damaged to the extent starship starts with (there was like 80 tiles removed before launch on purpose) it disintegrated on reentry, starship in the other hand can reenter and land quite precisely with extensive damage (which is in large part induced deliberately), and it did that multiple times already so it's definitely not a fluke

With respect (and noting we're getting far off-topic), the damage to Columbia on STS-107 was far greater and much more intensively localized than anything SpaceX has attempted with any Starship entry experiment. Punch a square-foot hole in the leading edge of one of Starship's flaps and let it enter from an apogee of 280km and see how it does before you make ill-informed and inaposite comparisons.

Thanks, Herb. I was trying to remember the other flight.

[Lee Jay]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

lol, you don't remember because when it was damaged to the extent starship starts with (there was like 80 tiles removed before launch on purpose) it disintegrated on reentry, starship in the other hand can reenter and land quite precisely with extensive damage (which is in large part induced deliberately), and it did that multiple times already so it's definitely not a fluke

Lee Jay,

I feel so bad that your and other members don't search and find out that even the space shuttle had its moments where numerous tiles came off and we almost lost a ship.

I lived through that. I don't need to read up on it.  I'm talking about the color change, burn through in areas where tiles weren't missing and all the rest of the obvious damage that wasn't from missing tiles.  I would have expected this vehicle to do better, not worse, because of it's larger size and thus (I'm assuming) lower ballistic coefficient.

[catdlr]

I don't remember the heat shield on Shuttle ever looking anywhere near this bad after reentry.  Why is this vehicle smoking the heat shield so badly?  Trajectory?  Heat shield material or thickness?  Something else?

lol, you don't remember because when it was damaged to the extent starship starts with (there was like 80 tiles removed before launch on purpose) it disintegrated on reentry, starship in the other hand can reenter and land quite precisely with extensive damage (which is in large part induced deliberately), and it did that multiple times already so it's definitely not a fluke

Lee Jay,

I feel so bad that your and other members don't search and find out that even the space shuttle had its moments where numerous tiles came off and we almost lost a ship.

I lived through that. I don't need to read up on it.  I'm talking about the color change, burn through in areas where tiles weren't missing and all the rest of the obvious damage that wasn't from missing tiles.  I would have expected this vehicle to do better, not worse, because of it's larger size and thus (I'm assuming) lower ballistic coefficient.

The comparison involves various metals, specifically aluminum and stainless steel. Oxidation results in colorful appearances. The tiles on the shuttle were tightly packed, whereas the tiles on the ship exhibit significant gaps that require filling with alternative materials currently under study. My point is that these should not be directly compared, as they are fundamentally different in nature. 

[CJ]

I'm curious about the Shuttle aft body flap, and also its ailerons; those had to stand up to reentry at near peak heating, as evidenced by their black tile coverings. So, they had (I assume, I do not know!) hinge joints that had to be protected.  I've tried looking for info on the design of it, though no luck so far.

Starship has had repeated issues with reentry plasma burnthrough damage at its flap joins.   

So, my question is, couldn't Starship have used a similar design to Shuttle for the hinge cover areas? I'm assuming there must be a reason, otherwise they would have done so.

[Twark_Main]

Try searching "elevons"

https://forum.nasaspaceflight.com/index.php?topic=50748.msg2599340#msg2599340

TL;DR the plasma hit the Shuttle hinge at an angle that's easier to shield against.

[Lee Jay]

This is what I'm saying.  Compare these two:
https://x.com/JennyHPhoto/status/1978208312660529282
https://en.wikipedia.org/wiki/Space_Shuttle_orbiter#/media/File:Space_Shuttle_Atlantis_landing_at_KSC_following_STS-122_(crop).jpg


Remember, most of the side of the Shuttle isn't even covered with tiles, but rather MLI blankets.


Why is SS so charred and discolored compared with Atlantis?

[Vultur]

I'm not sure it's apples to apples, for three reasons;

-  These Starship reentries are intentional stress tests. I don't think we've seen a "nominal, operational" Starship reentry.

- Also, the heat shield they're using seems to be a mix of experiments, not just the tile removal itself - I don't think it can really be compared to Shuttle's, which had to be fully operational from the first flight since all flights were piloted.

- Starship is made of stainless steel, Shuttle wasn't. The Ship structure can accept much higher temperatures than the Shuttle airframe could.

[envy887]

Why is SS so charred and discolored compared with Atlantis?

The charring is likely because the tile loss is resulting in a lot of ablation, both of the materials that are intended to ablate, which Shuttle didn't have; and those materials that aren't intended to ablate, which didn't happen on Shuttle because the gaps were filled better and fewer tiles were lost.

Dragon looks like a roasted marshmallow after recovery, and Falcon also chars (in addition to sooting) during reentry. Neither are really affected in their ability to be reused.

The stainless steel rainbow discoloration is simply because Starship has a heat-tolerant structure that operates at higher temps during reentry. This isn't necessarily a problem - actually, it's an indication of unnecessary insulation mass being left off, resulting in a performance improvement.

[Lee Jay]

Why is SS so charred and discolored compared with Atlantis?

The charring is likely because the tile loss is resulting in a lot of ablation, both of the materials that are intended to ablate, which Shuttle didn't have; and those materials that aren't intended to ablate, which didn't happen on Shuttle because the gaps were filled better and fewer tiles were lost.

Dragon looks like a roasted marshmallow after recovery, and Falcon also chars (in addition to sooting) during reentry. Neither are really affected in their ability to be reused.

The stainless steel rainbow discoloration is simply because Starship has a heat-tolerant structure that operates at higher temps during reentry. This isn't necessarily a problem - actually, it's an indication of unnecessary insulation mass being left off, resulting in a performance improvement.

Ablation is the opposite of "fully and rapidly reusable".

[JamesH65]

Why do you expect perfect results from what is still an R&D program? The heat shield is probably the most difficult of a all the problems they have to face so I think it's only fair to give them time to figure it out.

[DanClemmensen]

Why is SS so charred and discolored compared with Atlantis?

The charring is likely because the tile loss is resulting in a lot of ablation, both of the materials that are intended to ablate, which Shuttle didn't have; and those materials that aren't intended to ablate, which didn't happen on Shuttle because the gaps were filled better and fewer tiles were lost.

Dragon looks like a roasted marshmallow after recovery, and Falcon also chars (in addition to sooting) during reentry. Neither are really affected in their ability to be reused.

The stainless steel rainbow discoloration is simply because Starship has a heat-tolerant structure that operates at higher temps during reentry. This isn't necessarily a problem - actually, it's an indication of unnecessary insulation mass being left off, resulting in a performance improvement.

Ablation is the opposite of "fully and rapidly reusable".

Exactly. On SS the ablative material is a backup. If it ever ablates, that means that the primary TPS failed. It does allow the SS to be recovered, inspected, and reburbished, but that is a (possibly minor) repair, not normal "fully and rapidly reusable" operation.

[Lee Jay]

Why do you expect perfect results from what is still an R&D program? The heat shield is probably the most difficult of a all the problems they have to face so I think it's only fair to give them time to figure it out.

The issue I have is two-fold:

The Shuttle TPS didn't ablate.  The waterproofing burned off and tiles got damaged because it was side-mounted and thus in the debris stream from the tank, but the tiles themselves didn't ablate, I don't believe.  That was 50 year old technology.

Second, I think SS should have a lower ballistic coefficient than Shuttle and thus, I presume, a lower heating stress on the TPS.  It's possible that this assumption is incorrect but my thinking is that the SS is bigger but not that different in mass than a Shuttle on-entry (Shuttle usually weighed on the order of 100 metric tons on landing, if I recall correctly).

[InterestedEngineer]

 Perhaps many forget, but one time the Shuttle lost a tile in a critical area it didn't burn up. (STS-27)

Because that area happened to have a steel component underneath it.

Aluminum fails at about 300-650K.  Stainless at 1100-1600K.  Ranges are depending on whether it is stress bearing or not.

Stefan Boltzmann is a *4th* power equation.  This means that the hotter starship is emitting 16 times more energy when running at double the temperature.

The SS is the thing that saves Starship, as adequately demonstrated in zero failures in all the first five despite major damage to the heat shield.   

That same amount of damage would have destroyed a shuttle.

I note some but not all damage was intentional testing.

Going SS from carbon fiber was one of the smartest moves Elon every made.