After traveling through the inner solar system for seven years, NASA's MESSENGER spacecraft reached Mercury in March 2011 and became the first ever mission to orbit this mysterious planet. Since then MESSENGER has been making measurements with its suite of scientific instruments including gamma-ray, neutron and x-ray spectrometers, magnetometer, laser altimeter, cameras and other instruments. Join Morgan Burks, a physicist at Lawrence Livermore National Laboratory, to explore the mysteries surrounding Mercury's formation and composition and the instruments that need to work at cryogenic temperatures in one of the hottest places in the solar system. Series: "Lawrence Livermore National Lab Science on Saturday" [Science] [Show ID: 24905]