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.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.