CHICAGO (AP) — A newly announced project by billionaire innovator Elon Musk for a tunnel transit system that would carry travelers to and from Chicago O'Hare International Airport at up to 150 mph (241 kph) is just another project on a growing list of Musk dream projects. A look at some of the SpaceX and Tesla CEO's most ambitious projects, where they stand now and some hurdles to their completion: MARS MISSIONS Arguably Musk's boldest or most far-fetched project, depending on who you ask, is one to send manned missions to Mars.Read more on NewsOK.com