This X-ray image shows the interior of a palm-size 3D-printed heat exchanger inside Perseverance's Mars Oxygen In-situ Resource Utilization Experiment (MOXIE) instrument. Martian air will be carried into the tiny channels visible in the center of this part, where they'll be preheated. MOXIE will convert Martian air, which is mostly composed of carbon dioxide, into oxygen, which will be needed in industrial quantities as rocket propellant for launching astronauts back to Earth.
X-ray images like these are used to check for defects inside of parts; in this case, engineers checked to make sure the channels were free of the powder that the 3D printer melts in successive layers in order to produce the part.
NASA's Jet Propulsion Laboratory in Southern California built and will manage operations of the Mars 2020 Perseverance rover for NASA.
For more information about the mission, go to https://mars.nasa.gov/mars2020/.