Here is a solution for the space-gravity problem: rotating ball inside a ball, air bearing, magnetic rotation with active counterweight(could be pockets of water pumped around for example).,(reply>), ᴛʜᴀɴᴋs ғᴏʀ ᴡᴀᴛᴄʜɪɴɢ . ɢᴏᴛ sᴏᴍᴇᴛʜɪɴɢ ʙɪɢ ᴛᴏ sʜᴀʀᴇ ,ʟᴇᴀᴠᴇ ᴀ ᴍsɢ ʀɪɢʜᴛ ᴀᴡᴀʏ…