I believe the developer announced the possibility for an iPhone version a while back, not sure of the status now, or chances of an iPad version. http://www.mineshaft.org/site2.0/index.php?option=com_content&view=article&id=107:iphone-ho&catid=1:latest-news&Itemid=115
Matter of fact, the iPad version is out now. http://itunes.apple.com/us/app/spaceward-ho!/id510527152?mt=8