Steering is one of the 5 secondary Ship attributes, and affects your weapons' chance to hit. It is the counter to Agility.
The 9 Primary Ship Attributes
Shield, Structure, Movement, Range, Storage, Build-time, Attack, Transit-time, Slots
The 5 Secondary Ship Attributes
Agility, Defense, Steering, Critical-hit, Stability
Note that attack and defense modules have additional modifiers