Spoilers below.
I have destroyed the appropriate building in the Media Blitz campaign to unlock the secret mission. I got the notification that it has been unlocked, etc. I really didn't want to bother with finishing Media Blitz again, so I aborted.I looked for the mission once I was back on the ship, but am unable to find the mission. I was hoping that the secret mission unlock would work just like achievements, in that you can do what you need to do for the achievement, and abort the mission and still get it. Do I need to finish Media Blitz to be able to access the secret mission?
summary: Once I have unlocked the secret mission, do I need to finish Media Blitz to be able to access it, or can I abort the mission?
Best Answer
Your own experience confirms that yes, you do need to finish 'Media Blitz'.
The secret mission will appear on the star map, same as other "normal" missions.
Edit: note that you will have to play the secret mission before going to Char as once you start that, you won't be able to go back to do it.