A spacecraft at rest has moment of inertia of 100 kg-m^2 about an axis of interest. If a 1 newton thruster with a 1 meter moment arm is fired orthogonal to the axis of interest for 1 minute, how far has the vehicle rotated when the firing is complete?

The vehicle will rotate 18 rads after 1 minute of firing



What details of a real system does the previous question neglect?

The torque produced from the thruster is not a coupled moment, that is, it will produce some amount of translation along with the rotation. The question is also only regarding one axis of rotation, where a real system must consider an entire 3x3 inertia matrix and 1x3 torque.


What simple changes would you make to a basic PID controller if you expected the sensors to be very noisy and the target to change by large steps?

Increasing the gain on the integral term will help reduce large, steady-state noise; however, the system may be slower to react. The derivative gain can damp the response of the plant, help smooth out input, and reduce overshoot for large steps.