Basically Astral Projection is a different type of dreaming than lucid dreaming, or seems so. Think of it like having two bodies, the dreaming/astral Body and the normal waking one. The dreaming body can walk around in what looks like the real world. Scientists think it's based off of memory, so basically it's like you think you're awake but it's based off of memory or the dream re-creates reality so that it's similar to being awake, but you're not.

So if you can astral project, you can walk around in the memory re-created dream world, find the card and flip it over to see if it matches reality or if you know ahead of time, so basically that it is not actually based off memory.

Here are some links to help explain: http://www.skepdic.com/obe.html
http://www.astralinfo.org/index.htm
http://www.monroeinstitute.org/

I hope that better explains Astral Projection/OBE experiences.