Elon Musk unveils Tesla Semi electric big-rig truck

Tesla Inc unveiled a prototype electric big-rig truck Thursday night, throwing itself into a new market even as it struggles to roll out an affordable sedan on which the company's future depends. Chief Executive Elon Musk unveiled the big rig, dubbed the Tesla Semi, by riding the truck into an airport hangar near Los Angeles in front of an invited crowd of what Tesla said were potential truck buyers and Tesla car owners. Musk has described electric trucks as Tesla's next effort to move the economy away from fossil fuels through projects including electric cars, solar roofs and power storage. Some analysts fear the truck will be an expensive distraction for Tesla, which is burning cash, has never posted an annual profit, and is in self-described'manufacturing hell' starting up production of the $35,000 Model 3 sedan. Tesla shares were roughly flat on Thursday.