At 11:30, you can see that it was partly cloudy when they filmed the scenes of the astronauts disembarking their spacecraft. The reflection of the clouds and sun are clearly seen on Perry's helmet visor.
To accomplish the effect of an invisible forcefield being pressed against a man, the FX dept used a pane of glass. Unfortunately, you can see a reflection of the actor and a prop in his hands in it at 56:43 or so.
After attempting to shoot though the energy field with his pistol, the officer picks up some shell casings and looks at them with puzzlement - presumably they are meant to be the bullets (as he would expect to find shell casings on the ground after firing an automatic pistol).