WASHINGTON — SpaceX Chief Executive Elon Musk said that NASA should deorbit the International Space Station “as soon as possible,” preferably in the next two years, to focus on missions to Mars. The sudden call by Musk to end the ISS years earlier than NASA currently plans, made on social media Feb. 20, threatens to further complicate the relationship between Musk, a close adviser to President Donald Trump, and the space agency and much of the space industry. “It is time to begin preparations for deorbiting the @Space_Station,” Musk posted on X, the social media site he owns. “It has…