From planetary.org, check out this image of the International Space Station taken in the X-band (not to be confused with X-ray) area of the electromagnetic spectrum as it passed in front of a German Earth observation satellite named TerraSAR-X. From the article “In contrast to optical cameras, radar does not “see” surfaces. Instead, it is much more sensitive to the edges and corners which bounce back the microwave signal it transmits” which is why we see a ghostly outline. Truly an amazing image.