Using Gamma Rays and Neutrons to Measure the Elemental Composition of Planetary Bodies
Gamma rays and neutrons are used to measure the elemental compositions of planetary surfaces, which provide fundamental information to our understanding of how planetary bodies form and have changed over time. In this talk, I describe the technique of planetary gamma-ray/neutron spectroscopy, including what it is and how it is carried out. I will then tour the solar system, stopping off at locations where compositional measurements have made (or will make) important contributions to planetary science. Finally, gamma-ray and neutron detectors traveling around the solar system provide opportunities for scientific exploration beyond planetary science. Towards that end, I briefly review how planetary gamma-ray/neutron experiments contribute to areas of space and solar physics, astrophysics, and fundamental physics.
Technical Discussion: History and Lessons Learned from the Design, Building, and Operation of the MESSENGER Gamma-Ray and Neutron Spectrometer
This discussion will tell the history of the design and building of the MESSENGER Gamma-Ray and Neutron Spectrometer (GRNS). The MESSENGER mission to the planet Mercury was selected in 1999 and launched in 2004. During the time between selection and launch, the design of the GRNS was changed substantially due to new information learned after selection. I will trace the evolution of the GRNS design, including how and why it was changed, and the challenges associated with getting to final delivery on the MESSENGER spacecraft. By the end of the mission, data from the GRNS contributed to the top two (of 10) science discoveries of the mission.