Mercury, 16 Psyche, Mars, and Titan: Exploring the Solar System with Gamma Rays
Lawrence Livermore National Laboratory, in collaboration with Johns Hopkins Applied Physics Laboratory, built the gamma-ray spectrometer that flew on NASA's MESSENGER spacecraft to the planet Mercury. We are presently building two new gamma-ray instruments: one that will visit an exotic metal asteroid called 16-Psyche, and another to visit the moons of Mars (Phobos and Deimos). In addition, we have Phase-A funding to explore flying a gamma-ray spectrometer to Saturn's largest moon, Titan. Gamma rays reveal the elemental composition of these planetary bodies, which in turn helps us understand their formation and evolution. Each of these spectrometers is based on a high-purity germanium detector which gives the highest resolution for measuring the energy of gamma rays. However, they only do so when cryogenically-cooled to about -200°C. This talk will focus on gamma-ray spectroscopy, the interesting science that can be revealed with gamma-rays, and the hardware challenges of deploying a cryogenically-cooled spectrometer in deep space.