QUESTION:
Has any space junk hit the Hubble?

ANSWER from Al Vernacchio on March 27, 1996:
During the First Servicing Mission, astronauts noticed a hole in the high gain
antenna dish which was about the size of a quarter.  Also analysis from this
mission showed  over 260 small impacts to the HST aft shroud.  The sizes of 
the impact spots were from 0.07 cm to 3.43 centimeters with an average of 
0.6 centimeters. Also significant impacts were noticed on the returned solar 
arrays. So the HST environment is filled with many small pieces of space 
junk with no really large impacts observed.