Mission variable
From Elite Wiki
Mission variables are states that can be set and queried by a script in scripts.plist
They should have a unique name that is always prefixed by mission_. A good naming scheme is to use mission_ followed by a unique identifier for your script (for example, fredJamesMission1 followed by an underscore then the use to which the variable is being put (for example, _counter1 or _EnemyName.
Mission variables are saved in the player's saved game file.
Good Examples of Mission Variable Names
mission_fredJamesMission_counter1 // might be set to a number that's incremented or decremented every so often mission_trumbles_decisionKey // could be the result of a missionChoice mission_moonShot_stage // could be a phrase describing the current scripted action eg. BEGINNING_MISSION or KILLING_ALIENS or MISSION_COMPLETE
Poor Examples of Mission Variable Names
mission_counter mission_variable // no mission identifier mission_mymissionisaverycomplexaffairthatImightmisspell_andthisisanequallycomplexvariable // could be easily misspelt or misunderstood