It's been a few years since I last saw The Philadelphia Experiment but if memory serves this was an electrical insulation suit for surviving the temporal vortex thingy at the end of the movie. I quite like it and am somewhat surprised it didn't pop up after as a actual spacesuit. Maybe you all know different.
I think the helmet is familiar and looks to be one of the ones seen in Escape from the Planet of the Apes, Star Wars New Hope and Gets Smart. I believe it started life in Way..Way Out (1966) If it is the same then this would be the most recent appearance.