Enlarge / A Falcon 9 rocket launches in March, 2023. (credit: SpaceX) Nearly seven years ago, on a steamy morning in Florida, a small team of SpaceX engineers was fueling a Falcon 9 rocket for a pre-launch firing test of its nine Merlin engines. It had been a difficult but successful year for the California rocket company, which finally was starting to deliver on a long-promised increase in cadence of launches.