See Mars moon Phobos drift in front of Saturn
On March 1, 2018, the European Space Agency (ESA) released this video from its Mars Express spacecraft, which has been orbiting Mars since December 2003. The video combines 30 images as individual frames and shows Phobos passing through the frame with the gas giant planet Saturn, some 600 million miles (roughly a billion km) further away. Be sure to expand the video to full size to see Saturn as a small ringed dot in the background.
Bottom line: Phobos drifts in front of Saturn, as seen by Mars Express.