Data centers in space, moon hotels, human life on Mars. Those were just some of the ambitious opportunities Elon Musk laid out to JPMorgan Chase (JPM) CEO Jamie Dimon when asked why his rocket company SpaceX (SPAX.PVT) needed to go public now. The remarks came Thursday evening during a SpaceX pitch JPMorgan hosted at its Manhattan headquarters. It's part of a broader push by Wall Street to drum up demand for what's anticipated to be the world's largest IPO.