Scientist John Bonnell and mechanical engineer Bill Donakowski help with a test of how the electric field sensors will be deployed in space. This test takes place in a clean room. There are people outside the clean room helping with the test. These particular electric field sensors are balls on long wires called booms. The sensors are released, e.g. deployed, with the centrifugal force away from the spinning satellite since the booms are located in the spin plane of the satellite. As the satellite spins, the electric field sensors fly away from the satellite but are attached with the wire booms, much like spinning a ball on a string around your head. They are called “spin plane booms.”