Jason Perry works with the Cassini Imaging Team at the University of Arizona in Tucson, designing observations of Saturn's moon Titan and processing the returned images. Prior to joining Cassini in 2004, Jason worked with the Galileo Imaging Team, processing images of Jupiter's moon Io.
A fresh report was published online yesterday in Science Express on the discovery of a magma ocean beneath the surface of Io. Big news! This is a paper I've been looking forward to seeing for more than year and half.
This view of the anti-Jovian hemisphere of Io was captured by Galileo on February 20, 1997, on its "E6" orbit. The volcano named Prometheus, which has been erupting continuously since Voyager flew past, is in the center of the disk, with a curl of black lava exiting to its right.
The solar system contains dozens of objects that are large enough for self-gravity to make them round, and yet are not considered planets. They include the major moons of the planets, one asteroid, and many worlds in the Kuiper belt. The ones that we have visited with spacecraft are shown here to scale with each other. A couple of items on here are not quite round, illustrating the transition to smaller, lumpier objects.
This 12-frame mosaic from the Galileo Solid-State Imaging Experiment (SSI) covers much of the anti-Jovian hemisphere of Io at 1.45 km/pixel, with Jupiter in the background. Unlike the other mosaics from the I24 flyby, these images were acquired in full-frame mode. Images acquired in that mode did not suffer from the scrambling inflicted on the summation mode images during I24. This mosaic was designed as part of a stereo pair along with a similar mosaic acquired during C21 in July 1999; however, the relative blandness of much of the terrain outside Io's mountains and volcanoes, plus the unusual phase functions of many of its surface materials complicate the development of digital elevation models from these two data sets. The scrambled raw data for this image was unscrambled by a program developed at JPL using the LabVIEW software from National Instruments of Austin, TX.