NASA How low is Space Shuttle thermal protection's heat conductivity?

[Timothy S.]

How low is Space Shuttle thermal protection's heat conductivity?

Thank you

 

[berkeman]

Did you try searching online for more info about the Space Shuttle tiles? I'm guessing there's either a NASA article about them, or maybe a Wikipedia article about them. Please try that search and let us know what you find.

 

[.Scott]

The Space shuttle thermal protection is described in this wiki article.
There are several different methods used. And you would need to look at each one.
For example, this article goes into the different layers where carbon-carbon is used.
But the reinforced carbon-carbon RCC is not that good an insulator as documented in this NASA publication.
So other materials are used to back it up.
Also note that sometimes more than one value is used to describe the thermal conductivity. You would be interested in the "through-the-thickness" (t-t-t) value.

 

[Tom.G]

Many years ago I attended a talk by a NASA representative. He had a piece of the thermal tile used as the thermal shield on the Space Shuttle. The piece was a cube about 2 to 3 inches on a side. Based on its White color, and other public statements at the time, it was probably a ceramic aerogel.

He heated a spot on one surface with a propane blowtorch until it glowed Red. Then picked it up with his thumb and first finger on diagonal corners, thus showing its very low thermal conductivity. I don't recall that he gave any numbers though.

 

[.Scott]

Many years ago I attended a talk by a NASA representative. He had a piece if the thermal tile used as the thermal shield on the Space Shuttle. ...

A similar demonstration was presented on a TV talk show in the US around 1980. This NASA engineer had a somewhat curve piece that fit over his forearm. As with what @Tom.G saw, a blow torch was applied to the outer surface for about 12 seconds while the engineer was wearing it. Studio lighting was too bright to see any glow. The material he was using was light, apparently multilayered, and no more than a couple of centimeters thick.

It's thermal protection ability was described simply as "amazing" - with no specific numbers. The material he used did not seem to be reinforced carbon-carbon, so it would have been protecting less challenged areas of the shuttle envelope.

 

[Dullard]

Many years ago I attended a talk by a NASA representative. He had a piece if the thermal tile used as the thermal shield on the Space Shuttle. The piece was a cube about 2 to 3 inches on a side. Based on its White color, and other public statements at the time, it was probably a ceramic aerogel.

He heated a spot on one surface with a propane blowtorch until it glowed Red. Then picked it up with his thumb and first finger on diagonal corners, thus showing its very low thermal conductivity. I don't recall that he gave any numbers though.

Over a number of years, I built/serviced/re-built a lot of the equipment used in the TPS (thermal protection system) fabrication facility at KSC. The guy who ran the facility loved to do that demo - he'd even do it for people who were lost and just asking for directions.

 

[Klystron]

My duties as a software engineer at NASA Ames Research Center in 1980s included visiting different facilities to maintain and upgrade computers and standardized software.

The rather strange high-temperature blow-down wind tunnels that reproduce reentry conditions used to test thermal tile materials for space shuttle protection, usually had leftover tile pieces and fragments from successful, unsuccessful and deliberately over-stressed experiments.

Most materials appeared to be exotic lightweight ceramics, some carbon compounds and a few foams. Being pre-Internet, I am not certain what thermal data was digitized and now available online but NASA publications on retired shuttles can certainly be ordered at reasonable fees.

 

[Astronuc]

How low is Space Shuttle thermal protection's heat conductivity?

Name: LI-900 Rigid Tile
Database: NASA Ames Thermal Protection Materials
Category: Silicon-Based Reusable Composites: Rigid Ceramic Tiles
Composition: 100% SiO2
Manufacturer: United Space Alliance (USA)
Technical Readiness Level: 9

https://tpsx.arc.nasa.gov/Material?id=1

Thermal conductivity in plane 0.0675 W/m-K, uncertainty 0.012 W/m-K
144.2 kg/m³ (9 lb/ft³)

Shuttle Tile (LI-900) 0.048-0.126 W/m-K (varies with temperature)
http://mae-nas.eng.usu.edu/MAE_5420_Web/section3/appendix3.pdf

https://ntrs.nasa.gov/api/citations/19830003890/downloads/19830003890.pdf