Some of Elon Musk's luck may have rubbed off on Social Capital founder Chamath Palihapitaya, whose stake in Virgin Galactic Holding Inc. has more than tripled to top $1 billion this year. Palihapitaya holds the stake after the Palo Alto-based blank-check company he created helped Richard Branson take his New Mexico-based space tourism company public last fall. Palihapitaya, a former Facebook executive who is now CEO of startup investor Social Capital and an owner of the Golden State Warriors, last…