translation.en: I use RockSim to simulate flights before they go to see if they'll break supersonic, then fly them with onboard computers to verify performance.
translation.zh: 我用Rocksim（火箭弹设计软件）模拟飞行即将发射的火箭， 看看它们会不会突破音速， 然后用火箭搭载计算机控制飞行，验证火箭的性能。