> Is it going to be readily open to the public?

The scientific data will be available to the public, sometimes after a "proprietary" period (typically in the range 6–18 months) where the data is only accessible to the team who successfully proposed to obtain that data.

Not really my department! I do work at STScI, which operates the MAST archive that will eventually hold all this data, so I'm sure someone in my building knows.