vacuum specific impulse

例句：

1. 1.The vacuum specific impulse of the engine is crucial for its performance.
   发动机的真空特定冲量对其性能至关重要。
2. 2. The rocket's vacuum specific impulse was measured to be 300 seconds.
   火箭的真空特定冲量被测量为300秒。
3. 3.The research team used a vacuum specific impulse of 450 seconds to launch their spacecraft.
   研究团队使用真空特定冲量为450秒的冲量来发射他们的宇宙飞船。