Drift backwards when firing a weapon

Im trying to make a 0G game that when i shoot a weppon i drift backwords and when i change gravidy i dont get eny diference how could i fix this

This is how u do it ,if I understand u correctly

     GameObject instance = Instantiate(thePrefab,transform.position,Quaternion.identity)as GameObject;

     Destroy (instance.gameObject,0.5f);

U can play with transform.right and the number 50 that is the shooting force

Decrease the number for less force and increase to shoot faster.please vote me if u can