The Space Children (1958) - free on YouTube
Not a recommendation since it's a pretty silly movie, but several notable soon to be recognizable TV stars are in it. About the creation of a great satellite weapon that will beat the commies to the punch if they try to launch on U.S. However, a benevolent force from beyond the earth gets involved to try and stop such destruction.
It has Raymond Bailey (Milburn Drysdale of The Beverly Hillbillies), Russell Johnson (the Professor from Gilligan's Island) and Johnny Crawford (the kid from The Rifleman) in it. Mostly bad acting, but a bald and initially unrecognizable Raymond Bailey had an interesting character. I never realized that Mr. Drysdale wore a toupee.
Update to add: somehow I forgot the best one - Uncle Fester (Jackie Coogan)!