As long as you protect your vulnerable physical body while you are out, yes. And not just magickally but actually be sure to lock your doors because you're not going to realize if someone walks in and if they touch you they could pull you out too fast. It doesn't feel very good and could damage your energy a bit.
Unless you are a shaman who has undergone a near death experience to put yourself inbetween the worlds (yes that's what many native american shamans do) you can't die from astral travel. The most you'll get is a few aches if you lose a fight. But that's highly unlikely.