Question for those who know, 'cos I don't.
About ten years ago I found myself spending some time in Russia looking at Spacecraft systems, we covered re-entry technology.
The semi-spherical capsules built by the Russians (most notably Resurs and Soyuz) use a single piece moulded composite heat shield which ablates. and in the course of re-entry loses 10-20mm of thickness (for the unmanned Resurs capsules they actually re-use these once). Buran on the other hand, uses a form of thermal quilt, I believe using substances not chemically all that dissimilar to asbestos.
An obvious feature of both of these is that neither has or critical local attachments, which seem from most discussion to be the weak point on the Orbiter's system. So why did NASA go for this particular solution - is it because it's an obvious derivative of the system used on the Apollo capsules? NIH syndrome? Or were they genuinely convinced that it was the best solution available - in which case what are the faults in the Russian systems that I can't see?
G