Can you attempt more than one field goal in the same down?
No...not really. You can line up for a FG on 3rd down. If you get a bad snap, you can fall on the ball and then line up again on 4th down. But once a "kick" is attempted, you have given possesion of the ball to the other team. ----
The only way that could happen is if the kick was missed and there was a penalty that the kicking team accepted that would allow them to keep possession of the ball but would not give them a first down. *If the ball was kicked for goal, then charged down and recovered by the kicking team without having passed the line of scrimmage, the players might be able to reset and kick again. This has an extremely low probability of happening as the recovering player is likely to be downed or score a touchdown, and will never even consider attempting another kick.