In the spirit of classic sci-fi at the dollar store, here is a pack of six Christmas balls:
These are simply foam spheres with mirror pieces glued on them.
Pull gently, and the loop can be removed without damaging much of the ornament.
The mirror pieces work well around the middle of the ball, but there are gaps at the top and bottom.
I touched up the ornament with some Coat d'Arms acrylic silver. The paint also helped 'glue' down a loose mirror bit where the loop was pulled out. Alternately, a wash might do a better job of reaching every white spot.
A base can then be inserted into the soft styrofoam. Glue optional.
The Orions are blocked by a mysterious space buoy. It moves as they moves, and it will not let them pass.