NASA may be working toward an RCC repair solution.

The following is from the news report at:
"http://www.aviationnow.com/avnow/news/channel_aerospacedaily_story.jsp?id=news/tan01064.xml"

"The agency is considering three methods for RCC repair, which is
considered a more difficult problem (DAILY, Dec. 12, 2003). One
option for plugging small holes would be a fixture similar to a
molly bolt, Greenfield said, which would fit into the hole in the
hollow panel and open an umbrella-like fixture on the other side to
hold itself in place.

For larger holes or cracks, NASA is considering using a "glove" of
heat-resistant material that would be bonded on top as a covering.
The third repair method would involve filling the area behind the
crack with "a certain amount of mass to withstand the heat,"
Greenfield said."

- Ed Kyle