Likey likey.....

http://uk.reuters.com/video/2016/01/27/crash-proof-gimball-drone-explores-ice-c?videoId=367189207&videoChannel=4000&channelName=Technology

Neaty neaty!

Aha, must let our drone man know about this.

Mind you, it might bump off the walls of an ice cave without doing any harm,but just think what it could do in a highly decorated cave with lots of straws...

OK - I know you wouldn't use it in a place like that!  Great for up unexplored avens and down bottomless chasms to see what's at the top/bottom, though.