Please note:

The data in these directories are public data whose release is authorized by NASA.
Nothing here is sensitive or confidential.

Security Researchers: 
   We turn directory listings on for these directories only, to make it easier for users to navigate to the data, images, or animations that they are searching for.
   This setting is intentional, limited, controlled, and monitored.
   As the data that they reveal are all public and non-sensitive in nature, we believe that this setting does not pose a security risk or constitute a security vulnerability.
   But by all means, if you find an inadvertant disclosure of other data, or if you find some other configuration setting of our webserver that you feel poses a risk, then do please let us know.