Are the tiles on Starship going to need replacing after flight like the Shuttle? There isn’t a permanent material that can handle all the heat yet? Serious question, my space expertise is only from KSP.

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dotnet00 2 days ago | parent | next [-]

The intention is to need minimal to no replacement between flights. Part of the purpose of these tests is to figure out how to do that.

The tiles themselves work fine, but how to best mount them? where do you need them? Can you make them thinner? do you need anything underneath? what kind of gap do you need between tiles? Those are the things they're hoping to understand in these tests.

The Shuttle tiles were technically reusable AFAIK. The issue was that they were very fragile and the Shuttle for the most part could not tolerate any heat getting through the tiles (being aluminum), so every flight needed to have a perfect heat shield. Starship is a bit better on that end, as stainless steel is a lot more capable of tolerating heat and I think the tiles are a bit less fragile. Still, would be ideal to figure out how to not drop any tiles.

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JumpCrisscross 2 days ago | parent | next [-]

> Shuttle tiles were technically reusable

Would note that Shuttle tiles were never mass manufactured. The Shuttle’s shape meant lots of unique tiles. And its lack of mass production meant each tile was basically an artisanal object.

SpaceX aims to reüse tiles over many flights. But even if some tiles need replacing after each launch, that doesn’t tank Starship per se.

	▲	ralfd a day ago \| parent [-]
		Maybe even throwing a used ship away as scrap metal away would work as a business case. The expensive part are the rocket engines, if they can be reused much would be won.

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themafia 2 days ago | parent | prev [-]

> every flight needed to have a perfect heat shield.

Which is a little easier to do when your craft is shaped like a plane and not a simple cylinder. The loading and positioning were easier to model and then achieve in flight.

The shuttle also flew with repair kits and glue that could be used in a vacuum. The astronauts could perform an EVA and work to replace damaged tiles and there were published plans on how to do so. NASA unfortunately figured out very late that using the Canadarm to image the bottom of the shuttle immediately on achieving orbit was extremely necessary given the icing problems of the external tank.

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dotnet00 2 days ago | parent [-]

I thought that while the spare tiles did exist, there was never an actual safe procedure for replacing tiles (that didn't require being docked to the ISS) they were only carried to be available when the choice was between losing the entire crew on reentry or risking a crew member?

I don't quite understand how the airplane shape made it easier to model the loading and positioning? (Not saying you're wrong, just doesn't fit my intuition and I'm curious).

My understanding is that Shuttle didn't have to answer the questions about tile gaps etc because it used glue rather than mechanical attachments, if that's what you mean by positioning.

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mayama 2 days ago | parent | next [-]

> I don't quite understand how the airplane shape made it easier to model the loading and positioning? (Not saying you're wrong, just doesn't fit my intuition and I'm curious).

You can approximate space shuttle reentry to roughly a 2d surface entering atmosphere. Because of airplane shape, the tile side faces atmosphere and the plasma goes around plane edges. Where as starship being cylinder doesn't have any separation boundary and plasma roughly goes more than 180% of the cylinder.

	▲	nick49488171 a day ago \| parent \| next [-]
		IR reflectivity of stainless must help a good deal for the unshielded parts. I wonder if the internal surface is painted or finished in a way to help radiate the heat away internally. Is there any active cooling of any of the skin that we know of?
	▲	dotnet00 2 days ago \| parent \| prev [-]
		Ah, that makes sense!

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chrisbrandow 2 days ago | parent | prev [-]

Having seen the shuttle in person in LA museum, I was struck by how much it looked like a plane sitting on a flat heat shield surface

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floating-io 2 days ago | parent | prev [-]

Remains to be seen. That's what they want, but it's never been done before. (edit: clarity: they do NOT want to replace them after each flight.)

They're currently experimenting with things such as actively cooled tiles (which I presume were installed on this ship, since they were on the last two).

I personally think the likely best case is that they'll have to go over the ship and replace some here and there before launching again.

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ericcumbee 2 days ago | parent [-]

Even if they don't get to a no replacement....they still already have a massive improvement over Space Shuttle. The Space Shuttle basically every tile was unique, and and the pattern was different between the different orbiters. A good bit of the months of refurbishment of the Orbiter between flights was heat shield repairs. SpaceX has already shown from when they completely retiled one of the ships. they have cut down the time to replace a single tile down to minutes instead of the hours it took with the shuttle. The Tiles are also alot more standardized so they can be more mass produced than shuttle tiles.

	▲	floating-io 2 days ago \| parent [-]
		Absolutely! I think there are still a few unique tiles on Starship around joints and such IIRC, but either way, the number of tile types is much smaller for Starship. To my thinking, the sane sequence will be launch; catch; survey and maintain (heat shield and other items); and then launch again 24 hours later if everything checks out. And that will be an absolutely massive improvement over what we have today, let alone what we had with the Shuttle. I'm keeping my fingers crossed...