Virgin Galactic's shares have turned sharply lower after the spaceflight company said it’s made arrangements to sell up to $500 million in stock. The disclosure comes a day after founder Richard Branson briefly rocketed into space aboard Virgin’s winged space plane for the first time in what was the company’s highest-profile flight yet as it looks to begin taking up customers next year. Trading in the stock was briefly halted shortly after the stock market opened. It ended the day down more than 17%. But it is still up 71.5% so far this year.