The key to getting three star rating for this stage is to destroy everything with just two shots. With your first shot, you will have to wait for the right time so that when you slash your sword, you can kill all the satellites flying around.
Without killing the satellites, no additional enemies would appear.
Power Activation Point
Activate the power to destroy the floating piggy satellites.
With your second shot, similar to the first one you will have to wait for the right timing.
Second Power Activation Point
Blast them into each other to destroy the remaining piggies.
Second Shot Result
Once all of them are dead you will earn enough scores to qualify for three star mastery.