i've edited the
Scan page on the wiki to compile all the info related to Scanning for New Planets, including:
3 Scanning for New Planets
3.1 Chances to Scan a New Planet: Converted to Percentages (moved from the Max Planets Per Scan page)
3.2 Random Drops When Discovering a New Planet
3.3 Random Effects When Discovering a New Planet
3.4 Missions That Require Scanning for New Planets
it is very likely that i missed a few, so enlighten me and i will update.