I am currently trying out the "Experiments" extra. I have a probe in orbit which is basically a command pod, reaction wheels, solar panels, a battery, an antenna and three science experiment parts: Radiation Scanner, Barometer and Thermometer. Whenever I try to run one of those experiments, I just get a yellow text "no operator", but it did work on an earlier craft with a crew, which unfortunately was only suborbital. Do I need a crew to run those simple experiments? Is there a way to disable th