This movie was late 70's- early 80's. The one part I can vividly remember is people putting on goofy jumpsuits, climbing into a huge "astrodome" in front of thousands of people and floating into the air until they were vaporized. The gist was that the crowds and the participants all thought that being vaporized was some sort of "crossing over" event, if I remember correctly it was a bad bad thing.
Any help is really appreciated!