Building a linear actuator – a motorized mechanism that extends and retracts – that can be inexpensively replaced when shot, was challenge enough.
But you add another dimension of difficulty when you try to operate such a mechanism in the rain. When water travels down the shaft and into the actuation mechanism, hydroplaning can result that will cause lack of friction. Loss of friction = no extension and retraction.
It took some thinking and experimentation, but we now have a rain proof target extension and retraction capability operating at 100% reliability. The picture is of the "rain tire," treaded friction wheel that we developed as part of the solution.
Here is a video of me standing in the rain like an idiot watching a robot.
Targabot Swing'n in the Rain Video: https://youtu.be/hkXubi1tvbY