Depending on how you count it, SpaceX launched its 100th kerosene-fueled Merlin 1D rocket engine on a Falcon 9 rocket Feb. 11, underscoring what it says is an accelerated flight regime for the centerpiece of the company’s propulsion shop.
SpaceX will kick off a busy 2015 calendar playing catch-up, with liftoff of a Dragon supply ship for the International Space Station set for Tuesday after a delay from December.