Most common misconception about astral projection and obe is that you actually get out from your body. You never leave your body in conventional sense of means. You just dig deeper into your subconscious and your brain goes super fast. As a result of superfast processing (gamma waves) you wake up refreshed and energetic. Feeling of floating.
When you "reach" astral plane, you get into the collective consciousness of planet. And you cant die there, you never left anything and most certainly not your body.
You can get scared, of course. Which is not a nice experience.