New York — SpaceX says it plans to raise up to $75 billion when it goes public this month, setting the stage for the largest-ever stock market debut and putting Elon Musk — the world's richest person — on course to becoming the first trillionaire. The company, formally known as Space Exploration Technologies Corp., said Wednesday it will offer exactly 555,555,555 shares at $135 apiece in an initial public offering, French news agency AFP reports. The estimated proceeds would easily top the $26