SpaceX stock fell back down below its IPO price of $135 a share on Tuesday. Earlier this week, Elon Musk’s SpaceX (SPCX) surpassed its IPO price for the first time since mid-July. The stock is down 5.6% to 130.95 on Tuesday afternoon, according to MarketSurge. Tuesday’s retreat snaps a three-day winning streak in which SpaceX gained just under 30%. All…