QUESTION:
If the HST was pointed exactly in the direction of the sun or other bright
planets what exactly would the HST do?

ANSWER from Lynn Foster Bassford on April 26, 1996:
Actually, all of the science instruments in Hubble Space Telescope's payload
have a bright object detection.  This means that each instrument has its'
own limit for how bright the light entering can be.  If that limit is
exceeded, the instrument is commmanded to close its shutters and enter a
safe state.  The Hubble Space Telescope itself will close the aperature door
if too much light is detected.  If for some reason too much light enters
before the aperature door can close, the onboard optics risk being burnt out.