# How many heat shield tiles are installed on Starship and what is their total volume roughly?

If paired with tile density information, this total volume information would be useful for estimating how much more mass Starship could lift in a non-reusable configuration. If also paired with heat capacity and reflectivity information, it could also help people to determine whether the current heat shield has enough thermal mass to aerobrake when returning from GEO, landing on Mars, or returning to Earth from Mars.

At 1:24:00 in SpaceX's IFT3 broadcast, Kate says that there are 18,000 heat shield tiles on Starship.

Each hexagonal tile is 9.5" (0.2413m) across the short diagonal.

The area of the hexagonal tiles is 0.0504 $$m^2$$.

The thickness of the tile is 1 5/16th (0.033 m).

The volume of the tile is a bit trickier to work out since the back side is partially hollowed out.

On the backside, about 67% of the area of the tile is removed down to some unknown depth.

But if we assume that the depth is half the thickness, the volume works out to 0.00112 $$m^3$$.

So the total volume of all 18,000 tiles (if they were all the same size which they are not) would be roughly 20.11 $$m^3$$.

• According to a NASA document the Shuttle HRSI tiles had a density between 9-22 lbs/ft3. Using 15 pounds (250kg/m3) as an average that would give a total weight of about 5 metric tons for Starship's 20 m3 of tiles if my calcs are correct. If the Starship tiles are similar to the TUFROC used on the X-37 with a density of 25 lbs (400kg/m3) that would be around 8 tons. Extrapolating from Elon's past comments it would have been even more than that if they had stayed with carbon fiber instead of stainless steel, supposedly offsetting much of the weight advantage of carbon fiber. Mar 21 at 13:49
• Thanks! It would be super helpful if someone out there who has found a tile could weight it and measure its volume. Mar 21 at 18:03