At Tesla, Musk has overseen product development and design from the beginning, including the all-electric Tesla Roadster, Model S and Model X. Transitioning to a sustainable energy economy, in which electric vehicles play a pivotal role, has been one of his central interests for almost two decades. At SpaceX, Musk is the chief designer, overseeing development of rockets and spacecraft for missions to Earth orbit and ultimately to other planets. In 2012, SpaceX became the first commercial company to dock with the International Space Station and return cargo to Earth with the Dragon. In addition, Musk is the non-executive chairman and principal shareholder of SolarCity. SolarCity is now the leading provider of solar power systems in the United States. Prior to SpaceX, Musk co-founded PayPal, the world's leading Internet payment system, and served as the company's Chairman and CEO. Before PayPal, Mr. Musk co-founded Zip2, a provider of Internet software to the media industry.