So far the only way to get any information about the interior of rocky planets was from the moment of inertia which is related to a planets mass distribution. This only allowed to estimate if a planet has a mantle and what the estimated thicknesses of the core and mantle are. Of course, other (remote sensing) methods like potential (gravity and magnetic) fields can also give more information about a planets interior. However, the only solid way to determine the layer interface and their depth and thicknesses is seismic imaging, a popular technique used to image Earth’s subsurface and interior.
For more information: Cassini at Saturn
More on the Grand Finale (2nd dive: May 2, 2017; End of mission: Sept 15, 2017)
Origins Spectral Interpretation Resource Identification Security Regolith Explorer, or OSIRIS-REx mission, the first mission to sample an asteroid, was launched from Cape Canaveral on September 8. The launching rocket, an Atlas V 411, reached supersonic speed (video @ 01:10).
On October 28, 2015, Charles Elachi, the director of the Jet Propulsion Laboratory (JPL) of Lebanese origins, announced his intent to retire by June 2016 to become a professor emeritus at the California Institute of Technology (Caltech).
The following video includes Elachi’s announcement as well as an amazing summary of 15 years worth ofachievements at JPL & NASA
Full story @ JPL NASA
During Elachi’s visit to Lebanon in May 2006.