In a list of epic space missions to ever fly Cassini would be in good company near the top. In particular I like the star to the right of Enceladus. I am a little surprised to even see it. Generally exposure times would preclude any background stars at all, but the image was probably enhanced only enough to enhance the plumes of Enceladus the star was bright enough to show up. The question is what star was it? I like these types of mysteries, I may never solve it, however it won’t be for a lack of trying.
Original caption: Saturn’s moon Enceladus drifts before the rings, which glow brightly in the sunlight. Beneath its icy exterior shell, Enceladus hides a global ocean of liquid water. Just visible at the moon’s south pole (at bottom here) is the plume of water ice particles and other material that constantly spews from that ocean via fractures in the ice. The bright speck to the right of Enceladus is a distant star.
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 6, 2011, at a distance of approximately 90,000 miles (145,000 kilometers) from Enceladus.
The Cassini spacecraft ended its mission on Sept. 15, 2017.
Image: NASA/JPL-Caltech/Space Science Institute