dons anorak ....
Ballistic means something related to the science of ballistics.
"Ballistics is the science that deals with the motion, behavior, and effects of projectiles, especially bullets, bombs, rockets, or the like; the science or art of designing and hurling projectiles so as to achieve a desired performance."
The quote above comes from this wiki page, and contains enough detail for even the most pointy headed to be satiated.
It is also found in the term "to go ballistic". This usually occurs when the Badge sees a squaddie bimbling across his parade square with his hands in his pockets or a squaddie drops his rifle; moves at the wrong time or in the wrong direction; picks his nose; scratches his a*se or does anything else not in a "smart and soldier-like manner" whilst on parade.