After watching From the Earth to the Moon (see previous entry), I decided to do some digging into Lee Silver, the Caltech geologist who spent several years teaching geology to the Apollo crews. Played by David Clennon in the series, he appears in two episodes: Galileo Was Right and Le voyage dans la lune.
Now in his mid-eighties, Leon T. Silver retired from Caltech in 1996, where he remains W. M. Keck Foundation Professor for Resource Geology, Emeritus. This older page summarizes his research. He remains quite well known for his work on the Apollo program; when the HBO series came out, Silver talked about the differences between the series and real life (see also here). This contemporary article (1.5 MB PDF), which I presume is from a Caltech publication, profiles his work with the Apollo 15 crew, though in fact his work with the astronauts began with the Apollo 13 crew. Finally, Silver sat for a series of interviews about his life and career between 1994 and 2000; go to session 3 for his work on Apollo (he’s quite candid).