In the decade that the Cassini spacecraft has been orbiting Saturn, it has returned some pretty incredible images. Highlights include a clear view of Saturn’s hexagonal storm at the north pole, Saturn and a crescent Titan, and sunlight reflecting off of Titan’s seas. The latest addition to Cassini’s impressive portfolio is a collection of the most detailed colored maps of six of Saturn’s largest icy moons, excluding Titan. The images were taken throughout Cassini’s mission and were processed by Paul Schenk at the Lunar and Planetary Institute in Texas.
“Getting feature locations in planetary images is a complex business,” Schenk wrote on his blog, StereoMoons. In the blog post, he discusses the challenges of sifting through all of the images to make a cohesive mosaic map.
Some of the images obtained by Cassini used colors that exist outside of normal human vision. Utilizing the near-infrared and ultraviolet wavelengths revealed structures that could not be seen otherwise. Differences in color that can be seen within our visual spectrum depict charged particles, gas, and dust that are being vented from the planet. The differences in color is predicted to be due to differences in thickness of those features.
Though these maps are quite exceptional, they aren’t completely finished. The area surrounding the north pole of Enceladus and a couple of regions on Iapetus require more imaging, which Cassini is expected to complete in 2015.
Having detailed maps of the moons’ topography will be important for future research. Knowing where landmarks exist on these satellites will give scientists a frame of reference when studying key features, in addition to allowing them to track any geological changes that occur on the surface of the moons. Future missions that may require the use of a lander are more likely to be successful if possible landing sites can be identified ahead of time and the terrain is well-understood. This has the potential to save a considerable amount of time and money.
Cassini’s primary mission ended on July 30, 2008, but had been extended twice. The orbiter is expected to remain operational until it runs out of fuel in 2017. Cassini will be directed to enter Saturn’s atmosphere at the end of its mission. Because the moons Titan and Enceladus are two of the top candidates for possible extraterrestrial life, Cassini’s operators do not want to risk the spacecraft accidentally contaminating those locations.
Mimas
NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute
Enceladus
NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute
Tethys
NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute
Dione
NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute
Rhea
NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute
Iapetus
NASA / JPL-Caltech / Space Science Institute / Lunar and Planetary Institute
If you’d like to see these maps with a side-by-side comparison of maps generated from Voyager data from the early 1980s, check it out on JPL’s website.
Credit: Global maps of Saturnian moons Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus were produced by Dr. Paul Schenk (Lunar and Planetary Institute, Houston, TX) Image data are from the Imaging Science Subsystem (ISS) camera on the Cassini orbiter (NASA, JPL).
[Hat tip: Space.com]
