OrbitalHub

NASA dixit:

“February 14, 2017. Daphnis, one of Saturn’s ring-embedded moons, is featured in this view, kicking up waves as it orbits within the Keeler gap. The mosaic combines several images to show more waves in the gap edges. Daphnis is a small moon at 5 miles (8 kilometers) across, but its gravity is powerful enough to disrupt the tiny particles of the A ring that form the Keeler gap’s edge. As the moon moves through the Keeler gap, wave-like features are created in both the horizontal and vertical plane.

Images like this provide scientists with a close-up view of the complicated interactions between a moon and the rings, as well as the interactions between the ring particles themselves, in the wake of the moon’s passage. Three wave crests of diminishing sizes trail Daphnis here. In each subsequent crest, the shape of the wave evolves, as the ring particles within the crests collide with one another.

Close examination of Daphnis’ immediate vicinity also reveals a faint, thin strand of ring material that almost appears to have been directly ripped out of the A ring by Daphnis. The images in this mosaic were taken in visible light, using the Cassini spacecraft narrow-angle camera at a distance of approximately 17,000 miles (28,000 kilometers) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 71 degrees. Image scale is 551 feet (168 meters) per pixel.”

Image credit: NASA/JPL-Caltech/Space Science Institute

NASA dixit:

“January 30, 2017. In its season of “lasts,” NASA’s Cassini spacecraft made its final close approach to Saturn’s moon Mimas. At closest approach, Cassini passed 25,620 miles (41,230 kilometers) from Mimas. This mosaic is one of the highest resolution views ever captured of the icy moon. Close approaches to Mimas have been somewhat rare during Cassini’s mission, with only seven flybys at distances of less than 31,000 miles (50,000 kilometers).

Mimas’ surface is pockmarked with countless craters, the largest of which gives the icy moon its distinctive appearance. The left side, which is lit by reflected light from Saturn, has been enhanced in brightness in order to show the full surface. Imaging scientists combined ten narrow-angle camera images to create this mosaic view. The scene is an orthographic projection centered on terrain at 17.5 degrees south latitude, 325.4 degrees west longitude on Mimas. An orthographic view is most like the view seen by a distant observer looking through a telescope.

This mosaic was acquired at a distance of approximately 28,000 miles (45,000 kilometers) from Mimas. Image scale is approximately 820 feet (250 meters) per pixel. The images were taken in visible light with the Cassini spacecraft narrow-angle camera.”

Image credit: NASA/JPL-Caltech/Space Science Institute

NASA dixit:

“January 16, 2017. The wavemaker moon, Daphnis, is featured in this view, taken as NASA’s Cassini spacecraft made one of its ring-grazing passes over the outer edges of Saturn’s rings. This is the closest view of the small moon obtained yet. Daphnis (5 miles or 8 kilometers across) orbits within the 42-kilometer (26-mile) wide Keeler Gap. Cassini’s viewing angle causes the gap to appear narrower than it actually is, due to foreshorteneing.

The little moon’s gravity raises waves in the edges of the gap in both the horizontal and vertical directions. Cassini was able to observe the vertical structures in 2009, around the time of Saturn’s equinox. Like a couple of Saturn’s other small ring moons, Atlas and Pan, Daphnis appears to have a narrow ridge around its equator and a fairly smooth mantle of material on its surface — likely an accumulation of fine particles from the rings. A few craters are obvious at this resolution. An additional ridge can be seen further north that runs parallel to the equatorial band.

Fine details in the rings are also on display in this image. In particular, a grainy texture is seen in several wide lanes which hints at structures where particles are clumping together. In comparison to the otherwise sharp edges of the Keeler Gap, the wave peak in the gap edge at left has a softened appearance. This is possibly due to the movement of fine ring particles being spread out into the gap following Daphnis’ last close approach to that edge on a previous orbit. A faint, narrow tendril of ring material follows just behind Daphnis (to its left). This may have resulted from a moment when Daphnis drew a packet of material out of the ring, and now that packet is spreading itself out.

The image was taken in visible (green) light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 17,000 miles (28,000 kilometers) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 71 degrees. Image scale is 551 feet (168 meters) per pixel.”

Image credit: NASA/JPL-Caltech/Space Science Institute

NASA dixit:

“December 18, 2016. This image from NASA’s Cassini spacecraft is one of the highest-resolution views ever taken of Saturn’s moon Pandora. Pandora (52 miles, 84 kilometers) across orbits Saturn just outside the narrow F ring. The spacecraft captured the image during its closest-ever flyby of Pandora, during the third of its grazing passes by the outer edges of Saturn’s main rings.

The image was taken in green light with the Cassini spacecraft narrow-angle camera at a distance of approximately 25,200 miles (40,500 kilometers) from Pandora. Image scale is 787 feet (240 meters) per pixel.”

Image credit: NASA/JPL-Caltech/Space Science Institute

NASA dixit:

“November 27, 2016. Seen from outside, Enceladus appears to be like most of its sibling moons: cold, icy and inhospitable. But under that forbidding exterior may exist the very conditions needed for life. Over the course of the Cassini mission, observations have shown that Enceladus (313 miles or 504 kilometers across) not only has watery jets sending icy grains into space; under its icy crust it also has a global ocean, and may have hydrothermal activity as well. Since scientists believe liquid water is a key ingredient for life, the implications for future missions searching for life elsewhere in our solar system could be significant.

This view looks toward the Saturn-facing hemisphere of Enceladus. North on Enceladus is up and rotated 6 degrees to the right. The image was taken in green light with the Cassini spacecraft narrow-angle camera. The view was obtained at a distance of approximately 81,000 miles (130,000 kilometers) from Enceladus. Image scale is 2,566 feet (782 meters) per pixel.”

Image credit: NASA/JPL-Caltech/Space Science Institute

NASA dixit:

“In October 2017, The Lunar Reconnaissance Orbiter celebrates 100 lunar days of being at the Moon. Part 1 of this video series helps explain what a “lunar day” is, and what it means for the spacecraft’s mission to have been at the Moon for this period of time.”

Music provided by Killer Tracks: “Time is Running” – Dirk Ehlert, Guillermo De La Barreda; “Buckaroo Instrumental” – Alan Gold & Fiona Hamilton.

Video credit: NASA Goddard