Mars fever is hitting U.S. theaters with Matt Damon?s ?The Martian? heading for an opening weekend of about $50 million at 3,286 locations, according to early estimates Friday. 20th Century Fox?s release, which carries the fortuitous coincidence of NASA?s recent discovery of water on Mars, is dominating moviegoing. Ridley Scott?s action-adventure, starring Damon as an astronaut stranded on the Red Planet, is launching amid strong reviews following last month?s premiere at the Toronto Film Festival.