Elon Musk’s historic SpaceX debut caused a trading frenzy Friday, shooting the company to a $2.15 trillion valuation – but its sheer size is threatening to suck oxygen out of the rest of the market. The rocket-launch firm debuted on the Nasdaq just after 11:47 a.m. at $150 a share, making it the largest-ever IPO – and making Musk the world’s first trillionaire. The stock closed up 19% at $160.95. But other space stocks plummeted, suffering such big losses that they erased strong gains from the