The Cassini spacecraft snapped this image during the spacecraft’s closest flyby of Saturn’s moon Helene, on March 3, 2010.
Helene—just 33 kilometres, or 21 miles, wide—leads the much larger Dione by 60 degrees in the two moons’ shared orbit around Saturn. This makes Helene a “Trojan” moon of Dione, named for the Trojan asteroids that orbit 60 degrees ahead of and behind Jupiter as the giant planet circles the Sun.
The lit terrain seen here is on the side of Helene that faces away from Saturn. The southern pole of the moon is in the lower right of the image.
The image was taken in visible light with the Cassini spacecraft’s wide-angle camera. The view was obtained at a distance of approximately 1,900 kilometres (1,200 miles). The scale in the original image was 235 metres (771 feet) per pixel, but the image has been magnified by a factor of two and contrast-enhanced to aid visibility.
Adapted from information issued by NASA / JPL / Space Science Institute.