A plasma instrument (called PIMS) sensor assembly loaded into the 3D3 thermal vacuum chamber in the Space Simulation Laboratory (SSL) at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. The large number of wires that are visible demonstrate the intricate monitoring setup in place for the test. Thick copper-wrapped cables carry signals from the instrument to a spacecraft simulator outside the chamber to the right (some cables are not yet connected in this picture). Thinner wires carry temperature sensor data and power to test heaters toward the left and below the instrument. The instrument has several thermal zones that are independently monitored, and the resulting data feeds decision-making processes about how to operate the flight hardware.