![](https://appel.nasa.gov/wp-content/uploads/2008/03/2a1-670x380.jpg)
By Charles Tucker Spinning the upper stage of a rocket in flight is one way to stabilize the vehicle, just as a bullet spins to stay on course. But liquid propellant sloshing around in a spacecraft’s fuel tanks produces a wobble, or nutation, that can cause instability and alter flight trajectory. The rate of wobble […]