Jan 28 (Reuters) - Elon Musk's SpaceX is weighing a mid-June initial public offering, aiming to raise as much as $50 billion at a valuation ​of roughly$1.5 trillion, the Financial Times said on Wednesday, citing people ‌familiar with the matter. Reuters could not immediately verify the report. SpaceX did not respond to a Reuters ‌request for comment. SpaceX was most recently valued at about $800 billion in a secondary share sale last month, positioning the rocket and satellite company's listing among ...