While marching on a bivouac maneuver in (?) September 1954, I caught a glimpse overhead of a disc-shaped, metallic in color object that just came from nowhere straight down and stopped. The bottom was concave and very distinct in detail. I was called upon to "eyes front" while I marched, but I couldn't help but look back up and when I did, it just shot straight up from a large disc to nothing. What I mean is, it shot up at such speed that it kept getting smaller and smaller and then disappeared. I know what I saw and can draw a very vivid picture of it if needs be. It was definitely not a weather balloon ! ! I've never spoken of it. You just didn't do that. Until now. Thanks for listening.