More of an ignorant assumption. I asked ChatGPT now, and got this:
> In terms of shapes, the tiles were not uniform. In fact, there were over 17,000 different shapes used to fit specific areas of the shuttle's body. Each tile had to be individually manufactured and shaped to fit a precise location due to the complex curvature of the shuttle's surface. The unique shapes were necessary to ensure that every part of the shuttle received the proper protection against the extreme temperatures during re-entry.
Please don't cite LLMs for factual questions. They are prone to confabulation. Why not type the question "How many heat shield tiles did the Space Shuttle use?" into Google?
Since I mentioned I got the info from ChatGPT, people can decide for themselves how much they trust it.
Note that the question here is how many uniquely shaped tiles there was, not the total number.
This is interesting because if you have to manufacture and keep in stock 17,000 separate tile shapes, that will be vastly more expensive than SpaceX who, from what I hear, only uses a singe hex shaped tile everywhere.